JPH0218434B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic rotary machine used as a radial piston type hydraulic pump or hydraulic motor.

1 and 2 show a hydraulic pump as a radial piston type hydraulic rotary machine according to the prior art.

In the figure, reference numeral 1 denotes a main body casing of a hydraulic pump, and a ring-shaped sliding member 2 whose inner surface is a sliding surface 2A is fixedly provided on the inner peripheral portion of the casing 1. Further, a pintle valve 3 is provided in a protruding manner within the casing 1, and the pintle valve 3 is provided at a position eccentric to the sliding surface A. A rotor 4 is rotatably fitted into the pistol valve 3, and a rotating shaft 5, which is protruded into the casing 1 and faces the pistol valve 3, is connected to a bolt 6, 6, connected by... A plurality of stepped cylinders 7 are bored in the rotor 4 in the radial direction from the outer circumferential surface toward the center thereof, each consisting of a large-diameter cylinder 7A and a small-diameter cylinder 7B. Reference numeral 8 denotes a spherical receiving portion 8 inserted into the large diameter cylinder 7A, and the spherical receiving portion 8 is connected to the stepped portion of the large diameter cylinder 7A by a retainer ring 9 provided on the inner wall of the large diameter cylinder 7A. is held fixedly between. Reference numeral 10 denotes a spherical body which is swingably fitted into the spherical bearing part 8, and the spherical bearing part 8 and the spherical body 10 constitute a spherical bearing.

Further, 11 is bored in the spherical body 10, and the through hole 1
0A is shown, and the tip of the piston 11 is swingably connected to a shoe 11A, and the shoe 11A follows the rotation of the rotor 4 and moves on the sliding surface 2A. It is designed to be able to slide.

Further, reference numerals 12 and 13 indicate suction and discharge passages formed in the pintle valve 3, and each suction and discharge passage 12 and 13 opens into suction and discharge ports 14 and 15 formed in an arc shape on the circumferential surface of the piston valve 3, respectively. On the other hand, the rotor 4 is provided with a fluid passage 16 that allows the small diameter cylinder 7B to communicate with the suction and exhaust ports 14 and 15 intermittently. The small diameter cylinder 7B formed on the rotor 4 is closed on the large diameter cylinder 7A side by the spherical receiving part 8, the spherical body 10, and the piston 11. A cylinder chamber is formed in which the sucked hydraulic oil is pressurized and discharged to the other port.

The hydraulic pump according to the prior art has the above-mentioned configuration, and its operation will be described with the suction and discharge port 15 as a suction port and the suction and discharge port 14 as a discharge port.

Thus, when the rotating shaft 5 is driven to rotate,
The rotor 4 is rotated following this. Since the rotor 4 is provided eccentrically with respect to the sliding surface 2A, the piston 11 is caused to reciprocate within the cylinder 7 while the rotor 4 is rotating. While the small-diameter cylinder 7B forming the cylinder chamber communicates with the suction port 15 via the fluid passage 16, the piston 11 extends radially outward from the small-diameter cylinder 7B and performs a suction stroke in which hydraulic oil is sucked from the passage 13. Become. On the other hand, while the small-diameter cylinder 7B communicates with the discharge port 14, the piston 11 enters the small-diameter cylinder 7B, pressurizes the hydraulic oil in the small-diameter cylinder 7B, and discharges it into the passage 12 through the discharge port 14. It becomes a process. A pump action is performed by repeating this suction stroke and discharge stroke.

By the way, the radial piston pump has rotor 4.
Since the piston 11 is rotated eccentrically with respect to the sliding surface 2A, the piston 11 reciprocates within the cylinder 7 and is also rocked back and forth in the rotational direction. In the case of the prior art, a spherical receiving portion 8 is provided between the large diameter cylinder 7A and the piston 11 in order to allow the piston 11 to be swingably supported by the large diameter cylinder 7A.
A spherical bearing consisting of a spherical body 10 and a spherical body 10 is interposed, and the spherical body 10 slides on the spherical bearing portion 8, thereby making it possible for the piston 11 to swing. In addition, in order to prevent the piston 11 from colliding with the inner wall of the small diameter cylinder 7B even if it swings, the inner diameter of the small diameter cylinder 7B is
It is formed larger than the diameter of.

Therefore, the prior art hydraulic rotary machine having the above-mentioned configuration has the following drawbacks. First of all
In order to support the piston 11 in the large diameter cylinder 7A, a spherical receiving part 8 is interposed between the spherical body 10 fitted into the cylinder 7 and the large diameter cylinder 7A, and the spherical receiving part 8 is attached to a retainer ring. 9, which increases the number of parts, complicates the structure of the hydraulic rotating machine itself, and makes it troublesome to assemble. This has the drawback of increasing the size of the hydraulic rotating machine.

Second, the small diameter cylinder 7 forming the cylinder chamber
Since B has to be made larger in diameter than the diameter of the piston 11, even at the top dead center position when the piston 11 has entered the small diameter cylinder 7B the most, a considerable amount of hydraulic fluid is not discharged from the discharge port 14 and is discharged from the small diameter cylinder 7B. In this state, the small diameter cylinder 7
B is communicated with the suction port 15 on the low pressure side. Therefore, the non-discharge volume of the hydraulic oil at the top dead center position of the piston 11 described above becomes the dead volume of the hydraulic rotating machine, and the volume that expands when the high pressure hydraulic oil remaining in this dead volume returns to the low pressure side is This has the disadvantage of reducing the volumetric efficiency of the hydraulic rotary machine due to the apparent amount of leakage. Furthermore, when the dead volume becomes large, high-pressure hydraulic oil flows into the low-pressure side, which causes pulsation and increases noise.

Thirdly, since the structure is such that the hydraulic pressure in the small diameter cylinder 7B is received not only by the end surface of the piston 11 but also by the end surface of the spherical body 10, when the hydraulic rotating machine is operated at high pressure, The spherical body 10 is pressed outward in the radial direction of the rotor 4 and is brought into pressure contact with the spherical receiving portion 8 . For this reason, the lubricating oil film runs out on the sliding portion between the spherical body 10 and the spherical receiving portion 8, resulting in metal-to-metal contact, resulting in seizure, galling, and the like.

The present invention was devised in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a radial piston type hydraulic rotating machine having a simple construction and having a cylinder chamber with a small dead volume.

In order to achieve the above-mentioned object, a radial piston type hydraulic machine according to the present invention includes a ring-shaped casing whose inner surface is a sliding surface centered on the axis, and a ring-shaped casing whose inner surface is a sliding surface centered on the axis, and a ring-shaped casing located eccentrically with respect to the axis of the casing. a rotor having an axis and provided in the casing so as to be eccentrically rotatable with respect to the sliding surface; and a plurality of cylindrical holes bored in the rotor so as to pass through the rotor in the axial direction. , a cylindrical cylinder forming member rotatably fitted in each of the cylindrical holes, a cylinder chamber formed in each cylinder forming member in a direction perpendicular to its axis, and corresponding to each cylinder chamber. an insertion hole formed in the radial direction of the rotor at a position where the rotor A shoe is provided at the tip of the piston so as to be in sliding contact with the sliding surface of the casing.

With this configuration, the piston can be reciprocated while sliding in the radial direction along the inner wall of the cylinder chamber formed in the cylinder forming member, and the swinging movement of the piston back and forth in the rotor rotation direction is controlled by the cylinder. This can be done by rotating the forming member along the cylindrical hole.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 5.

In this figure, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and the explanation thereof will be omitted. However, 21 indicates the rotor,
The rotor 21 is provided with cylindrical holes 22, 22, . Reference numeral 23 denotes a cylinder forming member formed in a cylindrical shape, and a cylinder chamber 24 is formed in the cylinder forming member 23 by making a through hole in a direction perpendicular to the axis thereof, that is, in a radial direction. The cylinder forming member 23 is connected to the hole 2 of the rotor 21.
2, and the flange portion 5A of the rotating shaft 5 and the step portion 3 of the pistol valve 3
It is positioned by being held between A and A. The piston 11 is inserted into the cylinder chamber 24 through an insertion hole 21A formed in the rotor 21, and the piston 11 can reciprocate by sliding along the inner wall of the cylinder chamber 24. There is.

The hydraulic rotating machine according to the present invention has the above-described configuration, with port 15 serving as a suction port and port 1
When used as a hydraulic pump with 4 serving as a discharge port, the operation of the pump itself is not particularly different from that of the prior art described above. That is, as the rotor 4 rotates, the piston 11 is caused to reciprocate within the cylinder chamber 24 by the shoe 11A in sliding contact with the sliding surface 2A, and in the suction stroke, hydraulic oil is sucked into the cylinder chamber 24 from the suction port 15. In the discharge stroke, this hydraulic oil is discharged to the discharge port 14 while being pressurized. By the way, while the hydraulic pump is in operation, the piston 11 swings, but the direction of the swing is in the front-rear direction in the rotational direction of the rotor 21, and not in the direction perpendicular to the rotational direction. Here, the piston 11 is fitted into a cylinder forming member 23, and the cylinder forming member 23 is rotatably fitted into a hole 22 bored in the axial direction of the rotor 21. By rotating the piston 23 along the inner wall of the hole 22, the piston 11 can be made to swing in the direction of rotation of the rotor 21.

As mentioned above, since the cylinder forming member 23 is rotated within the hole 22 following the rocking motion of the piston 11, the cylinder chamber 24 is also caused to swing following the rocking motion of the piston 11. . For this reason, the inner diameter of the cylinder chamber 24 is made approximately the same as the diameter of the piston 11, and the piston 11 is
This means that it can be made to reciprocate while sliding along the inner wall of No. 4. Therefore, the volume of the cylinder chamber 24 at the top dead center position of the piston 11 can be made extremely small, and the dead volume can be reduced. As a result, the apparent leakage amount of the hydraulic rotating machine is significantly reduced, the volumetric efficiency is improved, and the flow of high-pressure hydraulic oil to the low-pressure side is reduced.
Pulsation is reduced and noise is reduced.

Further, during the discharge stroke of the hydraulic pump, the pressure inside the cylinder chamber 24 becomes high. Since the cylinder chamber 24 has a larger diameter than the fluid path 16, the pressure within the cylinder chamber 24 is received only by the piston 11, and the cylinder forming member 23 has no force pressing it outward in the radial direction. It never works. Therefore,
The lubricating oil film does not run out between the cylinder forming member 23 and the inner wall of the hole 22, and the cylinder forming member 23 can smoothly slide on the inner wall of the hole 22.

Further, the cylinder forming member 23 is fitted into the hole 22 of the rotor 21, and the cylinder forming member 23 is sandwiched between the stepped portion 3A of the pintle valve 3 and the flange portion 5A of the rotating shaft 5, and the piston 11 is moved into the cylinder chamber. Since it is configured so that it can be inserted into 24,
The structure is simple and assembly is easy. Moreover, since there is no need to form a large-diameter cylinder in the rotor as in the prior art, the axial dimension of the rotor 21 can be shortened, and the hydraulic rotating machine can be made compact.

In the above-mentioned embodiment, the radial piston type hydraulic rotating machine according to the present invention is used as a hydraulic pump, but it goes without saying that it may also be used as a hydraulic motor. Further, the hole 22 drilled in the rotor 21 is not a through hole, but is
It may also be a bottomed hole with one side closed. Furthermore, a configuration may be adopted in which a plate valve is used instead of the piston valve 3 to suck and discharge hydraulic oil into the cylinder chamber 24.

Since the radial piston type hydraulic rotating machine according to the present invention has been described in detail above, it achieves the following effects.

A cylinder forming member is fitted into a cylindrical hole bored in the axial direction of the rotor, a piston is inserted into a cylinder chamber formed in the radial direction of the cylinder forming member, and the piston is bored in the radial direction of the rotor. protrude outside through the provided insertion hole,
Since it is sufficient to simply provide a shoe at the tip of the piston, the structure is extremely simple.
Assembling becomes easier, and since there is no need to form a large-diameter cylinder in the rotor as in the prior art, the axial dimension and thickness of the rotor can be shortened, and the hydraulic rotating machine can be downsized.

Since the piston is configured to slide directly on the inner wall of the cylinder, the dead volume is minimized, improving volumetric efficiency, reducing pulsation, and reducing noise.

Since the hydraulic pressure in the cylinder chamber is received only by the piston, no pressing force in the radial direction within the cylindrical hole acts on the cylinder forming member, and the inner wall surface of the cylindrical hole between the cylinder forming member and the rotor. There is no risk of the lubricating oil film running out between the piston and the piston, and the piston can slide smoothly.

[Brief explanation of drawings]

Figures 1 and 2 show the prior art;
FIG. 1 is a longitudinal cross-sectional view of a hydraulic rotating machine, FIG. 2 is a cross-sectional view in the direction of the - arrow in FIG. 1, and FIGS. 3 to 5 show an embodiment of the present invention. is a longitudinal cross-sectional view of the hydraulic rotary machine, and FIGS. 4 and 5 are cross-sectional views taken in the direction indicated by the --, -- arrows in FIG. 3. 1... Casing, 2A... Sliding surface, 3... Pintle valve, 11... Piston, 11A... Shoe, 21
... rotor, 22 ... hole, 23 ... cylinder forming member,
24...Cylinder chamber.

Claims (1)

[Claims] 1. A ring-shaped casing whose inner surface is a sliding surface centered on an axis, and an axis located eccentrically with respect to the axis of the casing, and an eccentric rotation with respect to the sliding surface inside the casing. A rotor provided freely, a plurality of cylindrical holes bored in the rotor so as to pass through the rotor in the axial direction, and a cylindrical hole rotatably fitted in each of the cylindrical holes. a cylinder forming member, a cylinder chamber formed in each of the cylinder forming members in a direction orthogonal to the axis thereof, an insertion hole formed in the radial direction of the rotor at a position corresponding to each cylinder chamber; A piston is slidably inserted into each cylinder chamber through an insertion hole, and a piston is provided outside the rotor so as to be in sliding contact with the sliding surface of the casing at the tip of each piston. A radial piston type hydraulic rotating machine consisting of a