JPH03253775A - Variable-displacement inclined shaft type hydraulic machine - Google Patents

Abstract

PURPOSE:To support the side force without providing a special supporting means by providing thrust static pressure bearings and radial static pressure bearings so that the moment around a rotary shaft and around the x-axis and y-axis regarding the point of application of force of the resultant force of the average hydraulic reaction force is balanced. CONSTITUTION:Pistons 10 swayably connected with spherical sections 10A formed at the tip section to a drive disk 6 are inserted into multiple cylinders 9 provided on a cylinder block 8, and the concave end face at one end of the cylinder block 8 is coupled and supported on the convex end face of a valve plate 11. The thrust load component in the average hydraulic reaction force applied to the drive disk 6 and the side force are received by multiple thrust static pressure bearings 20, the radial load component is received by multiple radial static pressure bearings 26 respectively, and these bearings 20, 26 are arranged at the positions where the moment around a rotary shaft and around the x-axis and y-axis regarding the point of application of force of the resultant force of the average hydraulic reaction force is balanced and the positions where the side force is negated.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a variable displacement inclined shaft hydraulic machine used as a variable displacement inclined shaft hydraulic pump or a hydraulic motor, and particularly relates to a variable displacement inclined shaft hydraulic machine that is used as a variable displacement inclined shaft hydraulic pump or a hydraulic motor. The present invention relates to a variable capacity oblique shaft type hydraulic machine in which a rotating shaft is supported by a rotary shaft.

[Prior Art] Firstly, in a diagonal shaft type hydraulic machine, a drive disk of a rotating shaft and a cylinder block are connected via a piston that is reciprocatably provided to the cylinder block. Therefore, when a diagonal shaft type hydraulic machine is used as a hydraulic pump, the hydraulic reaction force that acts on the high pressure side piston during the discharge stroke is received by the rotating shaft via the drive disk, and similarly it can be used as a hydraulic motor. Suction (supply) if applicable
The hydraulic reaction force that acts on the high-pressure side piston during stroke is received by the rotating shaft via the drive disk.

Therefore, in this type of oblique shaft type hydraulic machine, since radial loads and thrust loads due to hydraulic reaction force act on the rotating shaft, the rotating shaft must be supported in a suspended state to support these loads. There is.

For this reason, in the conventional technology, a mechanical support type that mechanically supports a rotary shaft rotatably through a rolling bearing such as a roller bearing or a ball bearing that can receive radial load and thrust load, There are partial hydrostatic bearing support types, in which one load is mechanically supported by a rolling bearing, and the other load is supported hydraulically in a hydrostatic bearing, and a fully hydrostatic bearing support type, in which the entire load is supported hydraulically by a hydrostatic bearing. Are known.

Among these types of bearing support, hydraulic machines with partial hydrostatic bearing support support a rotary shaft with a fixed bearing and a movable bearing, as shown in Japanese Patent Application Laid-open No. 60-224981, and a movable bearing with a fixed bearing. A spring is provided on the outer ring in a direction opposite to the thrust load acting on the rotating shaft, and a suppressing piston that generates a pressing force in the same direction as the spring is provided on the outer ring side of the movable bearing, and the pressing piston is provided with a cylinder. A thrust static pressure bearing is known in which the pressure oil on the high pressure side in the block is guided.

On the other hand, as a fully hydrostatic bearing supported hydraulic machine,
As shown in Japanese Patent Application No. 9-131776, a bearing sleeve that supports radial loads and a bearing plate that supports thrust loads are provided in the casing, and a drive flange that also serves as a drive disk is movable between the bearing sleeve and the bearing plate. A rotary shaft is fixedly attached to one end face of the drive flange, a piston is connected to the other end face, and a radial hydrostatic bearing is formed between the outer peripheral face of the drive flange and a bearing sleeve. In addition to forming multiple pressure chambers that
A plurality of drive shoes constituting a thrust static pressure bearing are provided on one end surface of the drive flange, and an oil passage is provided in the piston and the drive flange to independently guide high pressure oil in the corresponding cylinder to the radial and thrust static pressure bearings, respectively. and
The high-pressure oil supports the radial load and thrust load on the hydrostatic bearing.

[Problems to be Solved by the Invention] By the way, when a variable capacity oblique shaft type hydraulic machine is applied as a hydraulic pump, the hydraulic reaction force acting on the high pressure side piston during the discharge stroke is rotated via a drive disk. It is received by the shaft, and the point of application of the resultant force of the hydraulic reaction force is located at a position eccentric to the axis of the rotating shaft. Moreover, as the cylinder block rotates, the position of the piston on the high pressure side and the number of pistons change, so the point of application of the resultant force of the hydraulic reaction force generally follows a trajectory like the letter "(1)". The center of the locus of the hydraulic reaction force is called the point of application of the resultant force of the average hydraulic reaction force. Note that even when the oblique shaft type hydraulic machine is applied as a hydraulic motor, the point of application of the resultant force of the hydraulic reaction force is located at a position eccentric to the axis of the rotating shaft.

As a result of the fact that the point of application of the resultant force of the hydraulic reaction force is located eccentrically with respect to the axis of the rotating shaft, the drive disk is not only subjected to load components in the radial and thrust directions, but also in both directions. The moment component induced by the load component of will also act.

Furthermore, side force is generated in the sliding portion of the valve plate of the hydraulic machine due to the shape of the suction/discharge port on the high pressure side. This side force acts via the piston or center joint of the hydraulic machine to deflect the drive disk of the rotating shaft to the side toward the high pressure side.

However, the prior art described above, especially the Japanese Patent Application Laid-Open No. 59
The device disclosed in Japanese Patent No. 131776 has nine pistons between the drive flange and the bearing sleeve, corresponding to the total number of pistons.
A radial static pressure bearing is constructed by forming pressure chambers at positions offset by 0 degrees and guiding high pressure oil from the corresponding pistons, and a drive shoe having pressure chambers corresponding to the total number of pistons on the drive flange. A thrust static pressure bearing is constructed by introducing high pressure oil from a corresponding piston, and each of these static pressure bearings receives a radial load, a thrust load, and a moment load around the rotation axis. Therefore, in the conventional radial and thrust hydrostatic bearings, only those in which high-pressure oil in the cylinder is guided through the corresponding pistons, that is, only the hydrostatic bearings located on the side where the resultant force of the hydraulic reaction force is applied, support the load. However, a hydrostatic bearing to which high-pressure oil is not guided, that is, a hydrostatic bearing located on the side of the point of application of the resultant hydraulic reaction force, does not have a load-supporting capacity.

Despite this, in the conventional technology described above, when a radial load, a thrust load, or a moment load around the rotating shaft acts, not only the hydrostatic bearing located on the side where the resultant force of the hydraulic reaction force is applied, but also the There is a problem in that the static pressure bearing located on the side of the point where the resultant force is applied also has to support these loads.

Furthermore, in order to support the side force without difficulty and to minimize the reduction in efficiency of the hydraulic machine, a support means dedicated to the side force should be provided in addition to supporting the piston hydraulic reaction force. Is required. for example,
If a hydrostatic bearing having the same concept as the above-mentioned known example is assumed as a means for supporting this side force, this will result in an additional location for supporting the hydrostatic pressure bearing in addition to the support for the piston hydraulic reaction force. This cannot be said to be a preferable support method from the viewpoint of ensuring the volumetric efficiency of the hydraulic machine and pump efficiency.

As a result, when supporting the piston hydraulic reaction force and side force, there is a static pressure bearing located at the point of application of the resultant force and capable of supporting the load, and a static pressure bearing located at the point of application of the resultant force and not capable of supporting the load. The balance of force between the bearing and the bearing is lost, and when supporting the radial component of the piston hydraulic reaction force and the side force at the same time, the balance of the hydrostatic bearing capacity is lost.2. The thickness of the oil film formed on the moving surface becomes uneven. As a result, metal contact is induced on the sliding surfaces located on the side of the force point where the resultant force of the hydraulic reaction force spreads, and the metal contact promotes uneven wear on each sliding surface, leading to an increase in leakage flow rate. There is.

In particular, due to long-term use, the sliding surface of the radial hydrostatic bearing, that is, the outer peripheral surface of the drive flange, which is the drive disk,
When the inner circumferential surface of the bearing sleeve wears, the gap formed between them widens, promoting unstable radial vibration of the drive flange and increasing contact vibration between the piston and the cylinder block. As a result, there are problems such as an increase in fretting wear at the contact point and an increase in the contact stress of the piston.

The present invention was developed in view of the problems of the prior art, and efficiently supports the piston hydraulic reaction force and side force acting on the drive disk, and also supports the radial and thrust directions even for long-term use. It is an object of the present invention to provide a variable capacity oblique shaft type hydraulic machine entirely supported by static pressure bearings, which prevents the occurrence of wear, has a low leakage flow rate, and provides high stability and reliability.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cylindrical casing provided with a head casing having a suction and exhaust passage;
a rotating shaft that is rotatably provided in the casing and whose tip end on the side that is inserted into the casing is a drive disk;
A cylinder block is disposed within the casing and has a plurality of cylinders bored in the axial direction, and each cylinder of the cylinder block is provided to be reciprocally movable, and one end side is swingably supported by the drive disk. a valve plate having a plurality of pistons and a pair of suction/exhaust ports, one end surface slidingly contacting the cylinder block, and the other end surface slidingly contacting the tilting sliding surface of the head casing in a tiltable manner; a tilting mechanism that tilts the valve plate together with the cylinder block; a thrust hydrostatic bearing and a radial hydrostatic bearing that receive piston hydraulic reaction loads and side forces in the radial and thrust directions acting on the drive disk; In the variable capacity oblique shaft hydraulic machine, each of the static pressure bearings has an oil passage that guides pressure oil sucked and discharged through a high-pressure side port of the pair of suction and discharge ports, wherein the thrust static pressure bearing and The radial hydrostatic bearing is located at a position that balances moments about the rotational axis and about an axis perpendicular to the rotational axis with respect to the point of application of the resultant force of the thrust and radial average hydraulic reaction force acting on the drive disk, and the side force It is characterized by being provided at a position where it cancels out.

Further, the drive disk has an end surface opposite to the piston support surface formed as a spherical part, and is located at one end side in the casing in a space between the outer peripheral side of the rotation shaft and rotatably supports the rotation shaft. a support member is provided, the support member has a surface facing the drive disk formed as an inclined surface,
A plurality of the thrust hydrostatic bearings are provided between the spherical portion of the drive disk and the inclined surface of the support member, and the radial hydrostatic bearing is provided between the outer peripheral side of the drive disk and the casing. A plurality of them can be provided at different locations.

In addition, the axis orthogonal to the axis of the rotating shaft is the X axis, and the y axis is
X
A first radial static pressure bearing is disposed above the axis and outside the variation range of the point of application of the resultant force, and is on the side of the point of application of the resultant force of the average hydraulic reaction force with respect to the y-axis. A second radial static pressure bearing is disposed above the X-axis, and a third radial static pressure bearing is further disposed below the X-axis on or near the y-axis.

In this case, regarding the first radial static pressure bearing, let eR be the separation distance on the X-axis between the sliding center of the static pressure pad and the point of application of the resultant force of the average hydraulic reaction force, and the static pressure The load component in the y-axis direction acting on the pad is f'+ty, and the distance on the X-axis between the sliding center of the hydrostatic pad and the point of application of the resultant force of the hydraulic reaction force with respect to the second radial bearing. If the distance is 8L and the load component in the y-axis direction acting on the static pressure pad is fLY, then the first and second
(6) The radial static pressure bearing is preferably disposed at a position that satisfies the following relationship: fRy×eR=fLyXe.

On the other hand, the axis perpendicular to the axis of the rotating shaft is the X axis, and the y axis is
X
A first thrust static pressure bearing is disposed above the shaft and outside the range of variation of the point of application of the resultant force, and a second thrust static pressure bearing is disposed at a symmetrical position of the X-axis from the first thrust static pressure bearing. A static pressure bearing is disposed, and a third thrust static pressure bearing is disposed above the X-axis on the side where the resultant force of the average hydraulic reaction force is developed, and further the third thrust static pressure bearing is disposed above the X-axis. A fourth thrust static pressure bearing is disposed at a symmetrical position with respect to the X axis. and,
Regarding the first and second thrust hydrostatic bearings, the distance on the X axis between the sliding center of the hydrostatic pad and the point of application of the resultant force of the average hydraulic reaction force is eR, and the first and the load component in the axial direction of the rotating shaft acting on the hydrostatic pad group A consisting of the second thrust hydrostatic bearing is W A
V, the load component in the direction perpendicular to the axial direction is WAH, and with respect to the third and fourth thrust hydrostatic bearings, the separation distance on the X-axis between the sliding center of the hydrostatic pad and the point of application of the resultant force; is eL, the load component in the axial direction of the rotating shaft acting on the static pressure pad group B consisting of the third and fourth thrust hydrostatic bearings is W Bv, and the load component in the direction perpendicular to the axial direction is W Bv. When W B +1 and the side force are Fv, the first to fourth thrust hydrostatic bearings satisfy the relationship W av X e R = W av X e L and the relationship WAH - WBH = Fv It is preferable to arrange the arrangement at a position that satisfies the requirements.

Further, in the present invention, a support member is disposed on one end side of the casing and is located in a space between the outer peripheral side of the rotation shaft and rotatably supports the rotation shaft, and the support member is connected to the drive disk. The opposing surface of the drive disk is formed as a concave spherical surface, and the drive disk is provided with the same number of thrust hydrostatic bearings as the number of pistons so that the static pressure pads are in sliding contact with the concave spherical surface, and the radial static pressure bearing is It is characterized in that a plurality of discs are provided between the outer peripheral side of the disk and the casing.

Furthermore, the variable capacity oblique shaft type hydraulic machine according to the present invention can be applied as a main hydraulic power source pump or drive motor in a hydraulic system for construction machinery.

[Function] With this configuration, even if fluctuating hydraulic reaction force and side force act on the drive disk,
By providing a thrust static pressure bearing and a radial static pressure bearing so that the moments around the rotation axis and around the x and y axes regarding the point of application of the resultant force of the average hydraulic reaction force are balanced, The moment around the axis can always be balanced, and side forces can be supported without the need for special support means.
It becomes possible to make the oil film thickness uniform on the sliding surface. As a result, the leakage flow rate can be minimized, and abnormal wear on the sliding surfaces can be prevented.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail using a variable displacement hydraulic pump as an example, with reference to the accompanying drawings.

1 to 5 show a first embodiment of the invention.

In the drawings, 1 indicates a casing, and the casing 1
The casing main body 2 is composed of a cylindrical casing body 2 consisting of a small diameter cylindrical portion 2A and a large diameter slanted cylindrical portion 2B, and a head casing 3 that closes the opening side of the slanted cylindrical portion 2B of the casing body 2.

Reference numeral 4 denotes a bearing sleeve as a support member provided in the small diameter cylindrical portion 2A of the casing body 2, and the bearing sleeve 4 is connected to the shaft portion 5A of the rotating shaft 5, which will be described later, and the inner periphery of the small diameter cylindrical portion 2A of the casing body 2. The sleeve part 4A is located in the space between the small diameter cylindrical part 2 and the sleeve part 4A.
The sleeve portion 4 is supported in contact with the inner step portion 2C of A.
The other end surface of A is formed as an inclined end surface 4B that is inclined inwardly so as to face a spherical surface 6B of a drive disk 6, which will be described later.

Reference numeral 5 denotes a rotating shaft with a shaft portion 5A extending through the bearing sleeve 4, and the tip of the rotating shaft 5 inside the casing 1 is connected to the rotating shaft 5.
A drive disk 6 in the form of a large diameter disk is integrally molded with the drive disk 6. The end surface of the drive disk 6 on the cylinder block side, which will be described later, becomes a piston support surface part 6A that supports the piston 10, which will be described later, and the opposite end surface becomes a spherical part 6B having a convex spherical shape similar to the valve plate 11, which will be described later. There is.

The rotating shaft 5 is connected to the bearing sleeve 4 via the bearing 7.
The drive disk 6 receives piston hydraulic reaction force and side force via a thrust static pressure bearing 20 and a radial static pressure bearing 26, which will be described later.

8 is a cylinder block that is provided in the casing 1 and rotates together with the rotating shaft 5, and the cylinder block 8 has a plurality of cylinders 9, 9, . ... are provided in the circumferential direction, and each cylinder 9 has a piston 1, respectively.
0,10. ... is provided so as to be able to reciprocate. A spherical portion 10A is formed at the tip of each piston 10, and the winter portion 10A is swingably connected to the piston support flat portion 6A of the drive disk 6.

Reference numeral 11 indicates a square valve plate, one end surface of the valve plate 11 has a convex spherical shape that slides in contact with the concave spherical end surface of the cylinder block 8, and the other end surface has a concave circle formed in the head casing 3. It has a convex arc shape so as to be in sliding contact with the arc-shaped tilting sliding surface 12, and a through hole is provided in the center of the valve plate 11 into which the tips of a center shaft 13 and a swing pin 19, which will be described later, are inserted from both sides. 11A is drilled. and,
A pair of supply/discharge ports (not shown) are bored in the valve plate 11 and communicate intermittently with each cylinder 9 as the cylinder block 8 rotates. Regardless, it communicates with a pair of supply/discharge passages (not shown) provided in the head casing 3 so as to open onto the tilting sliding surface 12 .

Reference numeral 13 denotes a center shaft that rotatably supports the cylinder block 8 between the drive disk 6 and the valve plate 11. The center shaft 13 has a spherical portion 13A formed at one end thereof, and the spherical portion 13A is connected to the drive disk 13. It is swingably supported at the axial center position of the disk 6. On the other hand, the other end of the center shaft 13 that protrudes through the cylinder block 8 is rotatably inserted into a through hole 1.1A drilled at the center of the valve plate 11. centering.

14 is a compression spring for applying preload to the sliding surface between the cylinder block 8 and the valve plate 11.

Reference numeral 15 denotes a tilting mechanism provided in the head casing 3 in order to tilt the valve plate 11 along the tilting sliding surface 12. A stepped cylinder hole 16 having holes 16A and 16B;
a servo piston 18 that is slidably inserted into the cylinder hole 16 and defines oil chambers 17A and 17B on both sides in the axial direction;
The swing pin 19 is inserted into the servo piston 18 and has a spherical tip end swingably inserted into the through hole 1tA of the valve plate 11. Then, by supplying pressure oil from an auxiliary pump (none of which is shown) to the oil chamber 17A or 17B via the oil passage hole 16A or 16B via the tilt control valve, the servo piston 18
The valve plate 11 and the cylinder block 8 are driven to rotate.

Next, the configuration of the hydrostatic bearing according to this embodiment will be described.

First, 2OA, 20B, 20C, and 20D are the first and second sections that receive the thrust load component and side force of the average hydraulic reaction force acting on the drive disk 6. Third. A fourth thrust static pressure bearing is shown, each of the thrust bearings 20A to 2
0D is located between the inclined end surface 4B of the bearing sleeve 4 and the end surface of the spherical portion 6B of the drive disk 6, and is arranged in a specific positional relationship similar to the radial hydrostatic bearing 26 described later. Here, each of the thrust hydrostatic bearings 20A to 20D has a cylinder hole 21A bored perpendicularly to the inclined end surface 4B of the bearing sleeve 4.

21B, 21C, and 21D, small diameter rod portions are slidably inserted into each of the cylinder holes 21A to 2LD, and
A hydrostatic pad 22A whose large diameter pad portion is located outside the inclined end surface 4B and slides into contact with the spherical surface portion 6B (hydrostatic bearing guide surface) of the drive disk 6.

22B, 22C, 22D, and each of the static pressure pads 22A to 2
A pressure chamber 23A is formed in the shape of a concave groove on the drive disk sliding surface side of the pad portion of the '2D.

23B, 23C, 23D and each cylinder hole 21A~
A throttle passage 24A is formed in each of the static pressure pads 2.2A to 22D so as to communicate the chambers in 2LD with the respective pressure chambers 23A to 23D.

It is composed of 24B, 24C, and 24D.

In addition, thrust static pressure bearings 20A to 20D, cylinder hole 2
1A to 21D, static pressure pads 22A to 22D, pressure chamber 23
A to 23D and throttle passages 24A to 24D are collectively referred to as a thrust static pressure bearing 20, a cylinder hole 21, a static pressure pad 22, a pressure chamber 23, and a throttle passage 24, respectively. Then, high-pressure oil is constantly guided to the pressure chamber 23 of the cylinder hole 21 of the thrust static pressure bearing 20 through an oil passage 25 (described later), which is sucked and discharged from the high-pressure side of the pair of suction and discharge ports. ing. Although only one thrust static pressure bearing 20 is representatively shown in FIG. 1, four thrust static pressure bearings are shown in FIGS. 3 and 4 similarly to the radial static pressure bearing 26. Bearings 20A to 20D are y-axis, y-axis
It can be arranged at a specific position on the sleeve portion 4A of the bearing sleeve 4 so that moment loads around the shaft are balanced. Although FIG. 3 shows an example of four thrust static pressure bearings, the number of thrust static pressure bearings 20 is not limited to this.

Reference numeral 25 denotes an oil passage that constantly supplies bearing control pressure to the thrust static pressure bearing 20 and a thrust static pressure bearing 26 (described later), and the oil passage 25 is formed in the casing 1 and the bearing sleeve 4. One end of the oil passage 25 is connected to the high pressure side suction and discharge port of the head casing 3 so as to guide high pressure oil sucked and discharged through the high pressure side port of the pair of suction and discharge ports bored in the valve plate 11. It opens at either the high pressure side suction and exhaust passage or the high pressure side piping outside the casing 1,
The other end of the oil passage 25 opens into each cylinder hole 21 of the thrust bearing 20 and each cylinder hole 27 of the radial static pressure bearing 26, so that bearing control pressure is supplied to these. Incidentally, the oil passage 25 may be constituted by an external pipe passing outside the casing 1.

Furthermore, 26A, 26B, 26C are drive disks 6
FIG. , a cylinder hole 27A that is bored in the radial direction on the inner peripheral side of the casing body 2 in a specific relationship that will be described later.

27B, 27C, and the small diameter rod portions are connected to each cylinder hole 2.
7A to 27C, respectively, while being slidably inserted,
Static pressure pads 7A, 28B, 28C whose large diameter pads located outside the respective cylinder chambers 27A to 27C slide on the outer circumferential surface 6C (static pressure bearing guide surface) of the drive disk 6, and the respective static pressure Pad 28A
Pressure chambers 29A, 29B, and 29C each formed in a groove shape on the drive disk sliding surface side of the pad portion of ~28C.
and a throttle passage 30 provided in the axial direction of the static pressure pads 28A to 28C so as to communicate the chambers in the cylinder holes 27A to 27C with the pressure chambers 29A to 29G, respectively.
It is composed of A, 30B, and 30C.

In addition, radial static pressure bearings 26A to 26C, cylinder hole 2
7A~27C1 Static pressure pad 28A~28C1 Pressure chamber 29
A to 2901 throttle passages 30A to 30C are collectively referred to as a radial static pressure bearing 26, a cylinder hole 27, a static pressure pad 28, a pressure chamber 29, and a throttle passage 30, respectively.

Here, the special arrangement of the radial static pressure bearings 26A to 26C will be described.

First, in FIG. 5, if the axis of the rotating shaft 5 is Z, and the axis perpendicular to the Z axis on the piston support surface 6A of the drive disk 6 is the y-axis, then the average hydraulic pressure due to the piston 10 located on the high pressure side is The point of application of the resultant force of the reaction force is O', and from the intersection O of the y-axis and the y-axis
Axial distance e. are separated by only Here, the point O' is called the point of application of the resultant force of the average hydraulic reaction force because the hydraulic reaction force F changes in the shape of "(1)" depending on the number of pistons on the high pressure side. It is from.

And when the tilt angle of the cylinder block 8 is α,
The radial load FR and thrust load FA due to the hydraulic reaction force are given by: When the tilting angle α is the minimum, the radial load FR is the minimum and the thrust load FT is the maximum.

On the other hand, when the tilt angle α is the maximum, the radial load FR is the maximum and the thrust load FT is the minimum.

Now, to describe the relationship between the installation of the radial static pressure bearings 26A to 26C described above, the first radial static pressure bearing 26
A is on the side of the force application point O' of the resultant force of the average hydraulic reaction force, and is outside the variation range of the force application point O' of the resultant force (to the right of the force application point O' of the resultant force in Fig. 2), and is located on the X-axis placed above the
The second radial static pressure bearing 26B is located on the opposite force point side of the resultant force application point O' with respect to the y-axis (left side of the y-axis in FIG. 2), above the X-axis, and as described later. The third radial static pressure bearing 26C is located below the X-axis and on or near the y-axis.

Regarding the first radial static pressure bearing 26A, the axis of the static pressure pad 28A and the outer peripheral surface 6C of the drive disk 6 are
If the intersection with OR is the X-axis direction component of the radial load fR acting on the intersection OR, let fRx be the X-axis direction component, and the Y-axis direction component be fRY, and the point of application of the resultant force of the average hydraulic reaction force O' and the intersection OR Let eR be the separation distance in the X-axis direction between the two. On the other hand, regarding the second radial static pressure bearing 26B, if the intersection of the axis of the static pressure pad 28B and the outer peripheral surface 6C of the drive disk 6 is OL, then the X-axis direction component of the radial load fL acting on the intersection OL is Let fLx, the Y-axis direction component be fLY, and let eL be the separation distance between the force application point 0' of the resultant force and the intersection OL.

In the above relationship, the first and second radial static pressure bearings 26A and 26B have f RYX e
r ″ f LYX e L −(2).

This makes it possible to balance the moment load M2 around the X-axis as described later.

Although the present embodiment is constructed as described above, the operation when the oblique shaft type hydraulic machine is used as a hydraulic pump will be explained next.

First, the tilt mechanism 15 tilts the valve plate 11 together with the cylinder block 8 to the maximum tilt position shown in FIG. For this purpose, pressure oil from the auxiliary pump is supplied to the oil chamber 17A of the cylinder hole 16 to displace the servo piston 18. As a result, the swing pin 19 is displaced together with the servo piston 18, and the valve plate 1 is guided by the tilting sliding surface 12 and tilted. As a result, the cylinder block 8 is tilted integrally with the center shaft 13. , its center of rotation is tilted with respect to the axis of the rotating shaft 5, resulting in the state shown in the figure.

Next, when the rotating shaft 5 is rotated by a drive source such as an engine or an electric motor, the drive disk 6 of the rotating shaft 5 is connected to the piston 10 inserted into each cylinder 9 of the cylinder block 8, so that the rotating shaft 5 is rotated. The cylinder block 8 is rotated together. As a result, each piston 10 reciprocates within the cylinder 9 while the cylinder block 8 is rotating. While each piston 10 is retracting from the cylinder 9, there is a suction stroke in which hydraulic oil is sucked into the cylinder 9 from the supply/discharge passage through the suction/discharge port. This is a discharge stroke in which the hydraulic oil in 9 is pressurized and discharged through the supply and discharge ports and the suction and discharge passage.

Here, in a diagonal shaft type hydraulic pump, the number of pressurizing pistons to generate discharge pressure (for example, if the total number of pistons is 7, the maximum number of pressurizing pistons is 4, and the minimum number of pressurizing pistons is 3). , the average number of pressurizing pistons is 3.5), a 2-ton screw hydraulic reaction load and a moment load act on the drive disk 6 in synchronization with the rotational speed of the rotating shaft 5. The load acting on the drive disk 6 is a radial load FR, which is a radial component force, and a thrust load F, which is an axial component force, on the support surface of the spherical portion 10A of the piston rod 10 of the drive disk 6. It is spread as. In this case, assuming that the axes orthogonal to the axis Z of the rotating shaft 5 are the X axis and the y axis, the piston hydraulic reaction force causes the X axis to move.

Moment loads M x , M around the y-axis and the X-axis
y.

M2 is induced. The load consisting of the piston hydraulic reaction force load and the moment load is supported by a thrust hydrostatic bearing 20 provided on the casing body 2 and a radial hydrostatic bearing 26 provided on the bearing sleeve 4, which is a supporting member. That is, the hydrostatic pad 2 of each of these hydrostatic bearings 20.26
The static pressure in the pressure chamber 23.29 provided in 2.28 acts hydrostatically and hydrodynamically, so that
the hydrostatic pad 22.28 acts as a plain bearing;
Supports both radial and thrust loads.

Here, of the loads acting on the drive disk 6, the support form for the radial load will be discussed in detail with reference to FIG.

First, the radial load F8 of the total piston hydraulic reaction force FK is:
As mentioned earlier, depending on the number of high-pressure side pistons located on the side of the force application point ○' of the resultant force of the average hydraulic reaction force, the resultant force changes in the shape of ωJ with the resultant force force application point O' as the center.

Moreover, the radial load F3 changes in synchronization with the number of pistons on the high pressure side, and becomes zero when the tilt angle α is Oo.
It is maximum when the tilt angle α is maximum.

Therefore, in this embodiment, the outer peripheral surface 6 of the drive disk 6
C side, as shown in FIG. 2, three radial static pressure bearings 26A to 26C are provided in a specific positional relationship with respect to the large diameter inclined cylinder portion 2B of the casing body 2,
These radial static pressure bearings 26A to 26G support the radial load FR acting on the drive disk 6, and also support the moment load M2 generated around the axis Z of the rotating shaft 5.

That is, the point O' of the resultant force of the average hydraulic reaction force is at a distance e from the axis Z of the rotating shaft 5. When the radial load FR acts on the point O' of the resultant force, the moment load M2 around the Z-axis is eccentric by the point O' of the resultant force.
Occurs as a moment related to.

However, in this embodiment, the force application point Oo of the resultant force of the average hydraulic reaction force
A first radial static pressure bearing 26A is provided on the side, and a second radial static pressure bearing 26B is provided on the side where the resultant force is applied.
6B is arranged in a special positional relationship that satisfies the above-mentioned formula (2). As a result, it is possible to support the moment load M2 around the two axes with respect to the force application point O' of the resultant force in a balanced state.

Now, a side force Fv is generated in the sliding portion of the valve plate 12 due to the shape of the suction/exhaust port on the high pressure side, etc. This side force FV acts on the drive disk 6 as Fv in the direction of the arrow in FIG. 4 via the piston 10 or the center joint 13.

However, in this embodiment, the drive disk 6 is provided with a spherical portion 6B having a convex spherical shape similar to the valve plate 11 on the end surface opposite to the piston support surface portion 6A, and further includes four thrust hydrostatic bearings 20A to 6B. 20D static pressure pads 22A-22
The thrust hydrostatic bearings 20A to 20D are arranged at special positions of the bearing sleeve 4 so that the thrust hydrostatic bearings 20A to 20D are in sliding contact with the spherical portion 6B serving as a hydrostatic bearing guide surface. Next, we will discuss special relationships.

That is, as shown in FIG. 3, the axes perpendicular to the axis of the rotating shaft 5 are defined as the y-axis and the y-axis is on the side of the force application point Oo of the resultant force of the average hydraulic reaction force, above the y-axis, and A first thrust static pressure bearing 2OA is disposed outside the variation range of the point of application of the resultant force, and the first thrust static pressure bearing 2OA is y
A second thrust static pressure bearing 20B is disposed at a symmetrical position across the axis, and a third thrust bearing 20B is disposed on the side of the force point where the resultant force of the average hydraulic reaction force is applied with respect to the y-axis, and above the y-axis. A thrust static pressure bearing 20C is disposed, and a fourth thrust static pressure bearing 20D is disposed at a position symmetrical to the third thrust static pressure bearing 20C with the y-axis in between. In this case, the separation distance on the X axis between the sliding center of the hydrostatic pad regarding the first and second thrust hydrostatic bearings 2OA and 20B and the point of application O' of the resultant force of the average hydraulic reaction force is defined as e++ and the first and second thrust hydrostatic bearings 2OA, 20B.
Let WAV be the load component in the axial direction of the rotating shaft 5 that acts on the group A of the static pressure pads 22A and 22B consisting of
Further, the load component in the direction perpendicular to the axial direction is assumed to be W A H. On the other hand, the third and fourth thrust static pressure bearings 20C,
20D, the distance on the X-axis between the sliding centers of the hydrostatic pads 22C and 22D and the point of application of the resultant force O' is eL, and the third and fourth thrust hydrostatic bearings 20
C.

The load component in the axial direction of the rotary shaft 5 acting on the static pressure pad group B consisting of 20D is defined as W' B v, and the load component in the direction perpendicular to the axial direction is defined as WBH. Under such conditions, the first to fourth thrust static pressure bearings 20A to
20D is arranged at a position that satisfies the relationship WAvX e R = WBVX e L -- (3), and WAH-W, , =
F V . . . The drive disk 6 is formed as a spherical portion 6B so as to satisfy the relationship (4).

As a result, as is clear from equation (4), the rotating shaft 5 is
Among the axes perpendicular to the axis Z, it is possible to generate a supporting force that has the same magnitude as the side force Fv and the opposite direction of action regarding the X-axis direction component.

In this way, the side force Fv can be supported by the thrust static pressure bearings 20A to 20D arranged in special positions of the bearing sleeve 4, and by adjusting the thrust force in the opposite direction, the side force Fv can be balanced. can be done.

Furthermore, the piston hydraulic reaction force F changes its resultant force as the number of pistons on the high pressure side changes, in the y-axis direction (upward and downward directions).
It fluctuates. However, as shown in FIG. 2, in this embodiment, the third
The configuration includes a radial static pressure bearing 26C.

As a result, even if the resultant force of the hydraulic reaction force changes due to a change in the number of high-pressure side pistons, this variation can be supported by the third radial static pressure bearing 26C.

As described above, according to this embodiment, the radial load FR acting on the force application point O' of the resultant force of the average hydraulic reaction force is
It can be well supported by the radial hydrostatic bearings 2.6A to 26C. At this time, the first and second radial static pressure bearings 26A.

By arranging 26B in a relationship that satisfies equation (2), it is possible to balance the moment load M2 around the Z-axis with respect to the point of application of the resultant force 0'. Moreover, the four thrust static pressure bearings 20A to 20D arranged at specific positions of the bearing sleeve 4 support the side force FV in the X-axis direction component perpendicular to the axis Z of the rotating shaft 5, and the third radial static pressure The bearing 26C can support the fluctuating portion of the resultant force of the hydraulic reaction force.

Therefore, the first to third radial static pressure bearings 26A to 26
C is such that the posture of the static pressure pads 28A to 28C is always maintained constant, and surface pressure can be applied to the sliding surface of each of the static pressure pads 28A to 28C in a normal posture, and extreme inclination support is possible. can be prevented. As a result, uneven wear of the static pressure pads 28A to 28C can be prevented, and the gap between the sliding surface of each of the static pressure pads 28A to 28C and the outer peripheral surface 6C (static pressure bearing guide surface) of the drive disk 6 The thickness of the oil film formed can be maintained uniformly. Therefore, the amount of leakage from the sliding surfaces of each of the static pressure pads 28A to 28C can be minimized, and the power loss associated with this leakage can be minimized.

Furthermore, four thrust static pressure bearings 20A to 20D are arranged at specific positions of the bearing sleeve 4, and a static pressure shaft pad 22A is provided.
The pad portion of ~22D is the spherical portion 6B of the drive disk 6
By slidingly contacting each thrust static pressure bearing 20A~
20D is piston oil 0 The thickness of the oil film formed on the spherical surface portion 6B is uniform with respect to the thrust load component FT of the pressure reaction force and the X-axis and the moment loads MX and M around the X-axis induced thereby. The side force Fv acting on the drive disk 6 is supported so that Side force FV can be efficiently supported.

Next, FIGS. 6 and 7 show a second embodiment of the present invention. Note that the same components as in the first embodiment described above are given the same reference numerals, and their explanations will be omitted.

However, the feature of this embodiment is that the drive disk is provided with the same number of thrust hydrostatic bearings as the number of pistons, and the supporting member is formed with a concave spherical hydrostatic bearing guide surface that receives the pad portion of the hydrostatic pad. By doing so, the thrust load FT of the piston hydraulic reaction force, the X-axis, and the moment load M around the X-axis.

, My and side force Fv are supported and hung. Note that the support form of the radial load Fll of the piston hydraulic reaction force F and the moment load M2 around the Z axis is the same as in the case of the first embodiment described above.

That is, in FIGS. 6 and 7, reference numeral 41 denotes a bearing sleeve of this embodiment as a support member provided in the small diameter cylindrical portion 2A of the casing body 2, and the bearing sleeve 41 is connected to the axis of a rotating shaft 42, which will be described later. The sleeve portion 4 is located in the space between the portion 42A and the inner peripheral side of the small diameter cylindrical portion 2A of the casing body 2.
1A, one end surface of the sleeve portion 41A is in contact with and supported by the inner step portion 2C of the small diameter cylindrical portion 2A, and the other end surface of the sleeve portion 4A is against which a pad portion of a hydrostatic pad 46 (described later) slides. It is a concave spherical surface portion 41B (static pressure bearing guide surface) having a concave spherical shape that is in contact with it.

Reference numeral 42 denotes a rotating shaft of this embodiment in which a shaft portion 42A is provided through the bearing sleeve 41, and the casing 1 of the rotating shaft 42 is
The inner tip is a large-diameter disk-shaped drive disk 43 that is integrally molded with the rotating shaft 42 . The end surface of the drive disk 43 on the cylinder block 8 side is connected to the piston 1.
0, but the opposite end is a flat surface part 43B unlike the first embodiment.
It becomes. The rotating shaft 42 is axially supported by a bearing sleeve 41 via a bearing 7, and the drive disk 43 is connected to a piston via a thrust hydrostatic bearing 49 (described later) and a radial hydrostatic bearing 26 used in the first embodiment. It is designed to receive hydraulic reaction force and side force.

Reference numeral 44 indicates a thrust static pressure bearing used in this embodiment, and the thrust static pressure bearing 44 has the number of pistons 10 (for example, seven) in the axial direction of the flat surface portion 43B of the drive disk 43.
Seven cylinder holes 45 are drilled corresponding to the cylinder holes 45, and the small-diameter rod portions are slidably inserted into the cylinder holes 45, and the large-diameter pad portion is inserted into the concave spherical portion of the bearing sleeve 41. 41B, a pressure chamber 47 formed in a groove shape on the sliding surface side of the static pressure pad 46, and a chamber in the cylinder hole 45 communicated with the pressure chamber 47, respectively. and a throttle passage 48 provided in the axial direction of the static pressure pad 523.

Each cylinder hole 45 according to this embodiment is connected to the spherical portion 10A of each piston 10, and connects to a liquid chamber 49 and an oil passage 50 provided in the drive disk 43, and an oil hole (not shown) in each piston 10. Self-discharged high-pressure oil is constantly introduced through the pump. Note that the thrust static pressure bearing 44 of this embodiment is representatively described in the case where it corresponds to one piston out of the number of pistons.

Although the present embodiment is constructed as described above, its operation as a hydraulic pump is not particularly different from that of the first embodiment.

Therefore, in this embodiment, the concave spherical surface portion 41 of the bearing sleeve 41
Since the concave spherical surface is used as the thrust hydrostatic bearing guide surface, the static pressure bearing capacity statically and dynamically generated on the concave spherical surface 41B is limited to the vertical pressure acting on the concave spherical surface 41B. W of acid component and rod thrust F of static pressure pad 46
A resultant force Wll synthesized by the parallelogram of the forces P and P acts in a direction perpendicular to the axial direction of the drive disk 43 and the rotating shaft 42. This resultant force WH acts in a direction opposite to the direction of side force Fv acting on the drive disk 43, that is, in a direction that cancels out side force FV.

As a result, in this embodiment, the side force Fv is balanced with the resultant force WH of the supporting force generated by the hydrostatic bearing corresponding to the number of pistons located in the high-pressure oil discharge area among the plurality of pistons. It can be supported by

In this way, in this embodiment as well, as in the first embodiment, surface pressure can be applied to the sliding surface of each static pressure pad 46 in a normal posture, and extreme tilt support can be prevented. can. As a result, uneven wear on the sliding surface of the hydrostatic pad 46 can be prevented, and the thickness of the oil film formed between the concave spherical surface portion 42B of the bearing sleeve 42 and the pad portion of the hydrostatic pad 46 can be made uniform. can be held. Therefore, the amount of leakage from the sliding surface of each static pressure pad 46 can be minimized, and the power loss associated with this leakage can be suppressed.

Furthermore, the side force Fv can be supported by canceling it with the resultant force WH generated on the hydrostatic bearing guide surface of each of the hydrostatic pads 46 in the direction perpendicular to the axial direction of the rotating shaft 55, so there is no special need for supporting the side force Fv. It is not necessary to provide proper support means.

On the other hand, the effects unique to the radial static pressure bearing 26 of this embodiment are the same as those of the first embodiment.

Furthermore, FIG. 8 shows a hydraulic circuit configuration diagram of a hydraulic system when the variable capacity oblique shaft type hydraulic machine according to each of the embodiments described above is applied to a construction machine such as a hydraulic excavator.

In the figure, 101 is an engine as a driving source;
2, 103 is a fully hydrostatic bearing type hydraulic pump according to an embodiment of the present invention; 104 is a control valve group for controlling the destination of fluid power supplied from the pump 102 and 103; 105
106 is a turning motor, 106 is a center joint indicating a relay point for fluid power from control valve details 104, and 107
．． 108 is a traveling hydraulic motor provided in the lower traveling body; 10
9 is a hydraulic cylinder for a packet, 110 is a hydraulic cylinder for an arm, 111 is a hydraulic cylinder for a boom, 112 to 12
0 is a pipe line connecting the hydraulic equipment elements.

In the hydraulic system for construction machinery configured as described above, when the hydraulic pumps 102 and 103 are driven by the engine 101 to discharge high-pressure fluid, this high-pressure fluid is passed through the control valve 104 to the swing hydraulic motor 105 which drives the swing system. Alternatively, the excavation work is carried out by supplying the oil to the traveling hydraulic motors 107 and 108 that drive the traveling system, and further to the boom, arm, and bucket 1 hydraulic cylinders 109, 110° 111, respectively.

However, when the hydraulic machine of the present invention is used as the hydraulic pumps 102 and 103 of the construction machine having the above configuration, the hydraulic pump 1 is used to increase running force and digging force and improve performance.
Even if the tilting angles of 02 and 103 are increased and the circuit pressure is increased, the amount of leakage flow is small, and a hydraulic pump with high stability and high reliability can be obtained. Note that similar effects can be obtained when applied as the swing motor 105 and the traveling hydraulic motors 107 and 108.

In addition, when applying the hydraulic machine of the present invention to a hydraulic motor capable of forward and reverse rotation, a pair of intake and exhaust ports formed on the valve plate,
Since both of the pair of suction and discharge passages formed in the head casing serve as high pressure ports, a shuttle valve is provided between the pair of suction and discharge ports or between the suction and discharge passages, and the high pressure side pressure is led out through the shuttle valve. The high pressure side pressure may be configured to be supplied to each static pressure bearing as a bearing control pressure.

Further, in the embodiment, the tilting mechanism 15 is provided in the head casing 3, but the tilting mechanism is provided on the side surface of the casing body 2, and one end is attached to the inside of the casing via the ear shaft. A structure may be adopted in which the yoke is tilted and the cylinder block and the valve plate are tilted by the yoke.

Furthermore, the hydraulic machine of the present invention is not limited to the above-mentioned application examples.
It can also be widely applied to hydraulic systems such as hydraulic reduction devices of rolling mills, powder molding machines, injection molding machines, high-speed forging machines in high-speed environments, and tunnel boring machines.

〔Effect of the invention〕

The present invention has been described in detail above, and even if a piston hydraulic reaction force that changes depending on the number of pistons on the high pressure side acts on the drive disk, the rotation axis and the Multiple thrust and radial static pressure bearings are installed so that the moments around the axis perpendicular to the rotational axis are always balanced, and the sides that occur on the sliding part of the valve plate due to the shape of the valve plate, etc. As an example of a form of force support, the drive disk or the bearing sleeve as a support member is formed into a spherical shape, and a plurality of thrust hydrostatic bearings are arranged at specific positions so as to be in sliding contact with the spherical surface. The following effects are achieved.

■ Since the thickness of the oil film formed between the sliding surfaces of the drive disk and the static pressure bearings in the thrust and radial directions can be made uniform, the thickness of the oil film formed between the sliding surfaces of the hydrostatic pads of the hydrostatic bearings and the drive disk Further, abnormal wear of the hydrostatic bearing guide surface of the support member can be prevented, and sufficient durability can be ensured even for long-term operation.

■Related to item (■) above, since the thickness of the oil film formed between the sliding surfaces can be made uniform, the leakage flow rate of pressure oil from the sliding surfaces can be minimized, reducing power loss. be able to.

■ The surface of the drive disk opposite to the piston support is made into a convex spherical shape, or the surface of the support member facing the drive disk is made into a concave spherical shape, and multiple thrust hydrostatic bearings are arranged at specific positions to make sliding contact with these spherical surfaces. With this configuration, it is possible to stably support the side force acting on the drive disk without requiring a special radial static pressure bearing for supporting the side force.

■ Of the multiple radial static pressure bearings, by arranging - radial static pressure bearings below the y-axis and on or near the y-axis axis, the radial load of hydraulic reaction force fluctuates. can also stably support the fluctuations.

[Brief explanation of drawings]

1 to 5 relate to a first embodiment of the present invention, FIG. 1 is a longitudinal cross-sectional view showing a variable capacity oblique shaft type hydraulic machine according to the first embodiment, and FIG. A cross-sectional view seen from the direction of the arrow II-II in the figure, and Figure 3 is a cross-sectional view of III-I in Figure 1.
ll A cross-sectional view seen from the direction of the arrow, Figure 4 is I in Figure 1.
V-TV An enlarged vertical cross-sectional view of the main part viewed from the direction of the arrow, FIG. 5 is an explanatory diagram showing the relationship between hydraulic reaction force, moment, and side force acting on the drive disk, and FIGS. 6 and 7 are views of the present invention. Regarding the second embodiment, FIG. 6 is a longitudinal sectional view showing a variable capacity oblique shaft type hydraulic machine according to the second embodiment, and FIG. 7 is a view taken from the direction of the arrow ■-■ in FIG. FIG. 8, which is an enlarged vertical cross-sectional view of the main parts, is a hydraulic circuit diagram when the hydraulic machine of the present invention is applied to a hydraulic system of a construction machine. 1...Casing, 2...Casing body, 3...
・Head casing, 4, 41...Bearing sleeve (supporting member), 41B...Concave spherical part, 5.42...1 rotation shaft, 6, 43...Drive disk, 6B...Spherical part , 7...Bearing, 8...Cylinder block, 9...
・Cylinder, 10...Piston, 11...Valve plate, 1
2...Tilt sliding surface, 13...Center shaft, 15
...Tilt mechanism, 20.44...Thrust static pressure bearing,
21.2745...Cylinder hole, 22,28.46.
・・Static pressure pad, 23, 29.47 ・・Pressure chamber, 24
, 30° 48... Throttle passage, 25... Oil passage, 2G
...Radial static pressure bearing. 2

Claims (7)

[Claims] (1) A cylindrical casing provided with a head casing having a suction/exhaust passage, a rotary shaft rotatably provided in the casing and having a drive disk at its tip end on the insertion side into the casing; a cylinder block disposed in the cylinder block and having a plurality of cylinders bored in the axial direction; and a plurality of pistons provided in each cylinder of the cylinder block so as to be reciprocally movable, one end of which is swingably supported by the drive disk. and a valve plate having a pair of suction/exhaust ports, one end surface of which is in sliding contact with the cylinder block, and the other end surface of which is in sliding contact with the tiltable sliding surface of the head casing in a tiltable manner, together with the cylinder block. a tilting mechanism for tilting the valve plate; a thrust static pressure bearing and a radial static pressure bearing for receiving the piston hydraulic reaction force loads and side forces in the radial and thrust directions acting on the drive disk; In a variable capacity oblique shaft type hydraulic machine comprising a pressure bearing and an oil passage guiding pressure oil sucked and discharged through a high pressure side port of the pair of suction and discharge ports,
The thrust static pressure bearing and the radial static pressure bearing are located at positions that balance moments around the rotation axis and around an axis perpendicular to the rotation axis with respect to the point of application of the resultant force of the average hydraulic reaction force in the thrust and radial directions acting on the drive disk. A variable capacity oblique shaft type hydraulic machine, characterized in that the machine is provided at a position where the side force is canceled out. (2) The end surface of the drive disk opposite to the piston support surface is formed as a spherical surface, and the drive disk is located on one end side in the casing in a space between the outer peripheral side of the rotating shaft and allows the rotating shaft to rotate freely. A support member is provided to support the drive disk, and the support member has an inclined surface facing the drive disk;
A plurality of the thrust hydrostatic bearings are located between the spherical portion of the drive disk and the inclined surface of the support member, and the radial hydrostatic bearing is located between the outer peripheral side of the drive disk and the casing. A variable capacity oblique shaft type hydraulic machine according to claim (1), wherein a plurality of variable capacity oblique shaft hydraulic machines are provided. (3) The axes orthogonal to the axis of the rotational axis are the x-axis and the y-axis.
x
A first radial static pressure bearing is disposed above the axis and outside the variation range of the point of application of the resultant force, and is on the side of the point of reaction of the resultant force of the average hydraulic reaction force with respect to the y-axis. A second radial hydrostatic bearing is disposed above the x-axis, and a third radial hydrostatic bearing is further disposed below the x-axis on or near the y-axis. 1) or (2)
Variable capacity oblique shaft hydraulic machine as described in 2. (4) Regarding the first radial static pressure bearing, the distance on the x-axis between the sliding center of the hydrostatic pad and the point of application of the resultant force of the average hydraulic reaction force is e_R, and the static pressure The load component in the y-axis direction acting on the pad is f_R_Y,
Regarding the second radial bearing, let e_L be the separation distance on the x-axis between the sliding center of the hydrostatic pad and the point of application of the resultant force of the hydraulic reaction force, and the y-axis that acts on the hydrostatic pad. If the load component in the direction is f_L_Y, the first,
The second radial static pressure bearing is arranged at a position that satisfies the relationship f_R_Y×e_R=f_L_Y×e_L.
Variable capacity oblique shaft hydraulic machine described in ). (5) The axes perpendicular to the axis of the rotating shaft are the x-axis and the y-axis.
x
A first thrust static pressure bearing is disposed above the shaft and outside the range of variation of the point of application of the resultant force, and a second thrust static pressure bearing is disposed at a position symmetrical to the x-axis with respect to the first thrust static pressure bearing. A pressure bearing is disposed, and a third thrust static pressure bearing is disposed above the x-axis on the side of the reaction force point of the resultant force of the average hydraulic reaction force, and further, a third thrust static pressure bearing is disposed above the x-axis. A fourth thrust static pressure bearing is arranged at a symmetrical position with respect to the x-axis, and with respect to the first and second thrust static pressure bearings, the sliding center of the static pressure pad and the point of application of the resultant force of the average hydraulic reaction force are Let e_R be the separation distance on the x-axis between The load component in the direction perpendicular to the axial direction is W_A_H, and for the third and fourth thrust hydrostatic bearings, the separation distance on the x-axis between the sliding center of the hydrostatic pad and the point of application of the resultant force is e_L. At the same time, a load component in the axial direction of the rotating shaft acting on the hydrostatic pad group B consisting of the third and fourth thrust hydrostatic bearings is W_B_V, a load component in a direction perpendicular to the axial direction is W_B_H, and Side force F_V
Then, the first to fourth thrust static pressure bearings satisfy the relationship W_A_V×e_R=W_B_V×e_L and are disposed at positions satisfying the relationship W_A_H−W_B_H=F_V. 1
), (2) or (3) variable capacity oblique shaft hydraulic machine. (6) A cylindrical casing provided with a head casing having a suction/exhaust passage, a rotating shaft rotatably provided in the casing and having a drive disk at its tip end on the side inserted into the casing, and a rotary shaft provided inside the casing. a cylinder block disposed in the cylinder block and having a plurality of cylinders bored in the axial direction; and a plurality of pistons provided in each cylinder of the cylinder block so as to be reciprocally movable, one end of which is swingably supported by the drive disk. and a valve plate having a pair of suction/exhaust ports, one end surface of which is in sliding contact with the cylinder block, and the other end surface of which is in sliding contact with the tiltable sliding surface of the head casing in a tiltable manner, together with the cylinder block. a tilting mechanism for tilting the valve plate; a thrust static pressure bearing and a radial static pressure bearing for receiving piston hydraulic reaction loads and side forces in the radial and thrust directions acting on the drive disk; In a variable capacity oblique shaft type hydraulic machine comprising a pressure bearing means and an oil passage for guiding pressure oil to be sucked and discharged through the high pressure side port of the pair of suction and discharge ports, one end side in the casing is provided. A support member is disposed in a space between the outer peripheral side of the rotation shaft and rotatably supports the rotation shaft, and the support member has a surface facing the drive disk as a concave spherical surface, and the support member has a concave spherical surface facing the drive disk. A number of thrust static pressure bearings equal to the number of pistons are provided so that the static pressure pads are in sliding contact with the concave spherical surface portion, and a plurality of radial static pressure bearings are located between the outer peripheral side of the drive disk and the casing. A variable capacity oblique shaft type hydraulic machine characterized by the following: (7) A variable capacity oblique shaft hydraulic machine according to claim (1) or (6), which is applied as a main hydraulic power source pump or drive motor for use in a hydraulic system of construction machinery.