JPH01210656A - Hydrostatic continuously variable transmission - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Field of Application The present invention provides a method for coaxially and integrally coupling a pump cylinder of a swash plate type hydraulic pump and a motor cylinder of a swash plate type hydraulic motor to each other. An annular high-pressure oil passage that communicates with the motor boat that exists in the expansion stroke area of the hydraulic motor and an annular low-pressure oil passage that communicates with the motor boat that exists in the contraction stroke area of the hydraulic motor are concentrically connected between the pump cylinder and the motor cylinder. A large number of distribution valves are arranged radially and can reciprocate between radially outer and inner positions to alternately communicate the large number of pump ports of the hydraulic pump with the high-pressure oil passage and the low-pressure oil passage. , an eccentric wheel circumscribing these distribution valves is connected to an input member of the hydraulic pump such that it can move between a clutch-off position and a clutch-on position, and in a first eccentric position of the eccentric wheel, the eccentric wheel is in the discharge stroke region of the hydraulic pump. The pump port located in the suction stroke area is connected to the high pressure oil passage, and the pump port located in the suction stroke area is connected to the low pressure oil passage, and the distribution valve is controlled to short-circuit the hydraulic pump at the second eccentric position. Regarding hydraulic continuously variable transmissions.

(2) Prior Art The present applicant has already proposed such a hydrostatic continuously variable transmission as disclosed in Japanese Patent Application Laid-Open No. 62-224769.

(3) In the hydrostatic continuously variable transmission proposed in response to the number of problems to be solved by the invention, an external operating member is connected to the eccentric wheel via a cam mechanism, and by manually operating this operating member, the eccentric Since the position of the wheels is controlled, the structure is complex and operation is troublesome.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a hydrostatic continuously variable transmission with a simple structure that can automatically control the position of the eccentric wheel according to the rotational speed of the input sleeve. do.

B1 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention connects a clutch spring that biases the eccentric wheel toward the clutch-off position, and also connects the clutch spring to the eccentric wheel. It is characterized by the attachment of a weight capable of exerting a centrifugal force that moves the eccentric wheel toward the clutch-on position against the spring force of the spring.

(2) Action When the input member rotates, the eccentric wheel also rotates, and a centrifugal force is generated in the weight of the eccentric wheel in a direction opposite to the direction of the spring force applied to the eccentric wheel by the clutch spring.

Therefore, when the rotational speed of the input member is relatively low, the centrifugal force cannot overcome the spring force of the clutch spring.
The eccentric is held in a clutch-off position by a clutch spring, which controls the distribution valve to short-circuit the hydraulic pump.

When the rotational speed of the input member increases to a predetermined value or higher, the centrifugal force overcomes the spring force of the clutch spring and shifts the eccentric wheel to the clutch-on position, thereby starting hydraulic power transmission from the hydraulic pump to the hydraulic motor. (Controls the distribution valve.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

First, in FIG. 1, a power unit U for a motorcycle consists of an engine E and a hydrostatic continuously variable transmission aT, and the crankshaft 1 of the engine E and the continuously variable transmission T are housed in a common casing 4. Supported. Continuously variable transmission T
The input cylinder shaft 5 and the output shaft 15 are arranged parallel to the crankshaft 1, and the crankshaft 1 drives the input cylinder shaft 5 via the primary reduction gear 2, and the output shaft 15 drives the secondary reduction gear 3. The rear wheel (not shown) of the motorcycle is driven through the motor.

In FIGS. 1 and 2, the continuously variable transmission T includes a constant displacement swash plate hydraulic pump P and a variable displacement swash plate hydraulic motor M.

The hydraulic pump P includes an input cylinder shaft 5 as an input member, a pump cylinder 7 fitted to the inner circumferential wall of the input cylinder shaft 5 via a ball bearing 6 so as to be relatively rotatable, and an axis line of the pump cylinder 7. Pump plungers 9.9... that slide inside a large number of odd number of cylinder holes 8.8... provided in an annular arrangement surrounding the pump plungers 9.9... The pump swash plate 10 is brought into contact with the front surface thereof, and the pump swash plate 10 is aligned with the virtual trunnion axis 0.0, which is orthogonal to the axis of the pump cylinder 7. and a pump swash plate holder 12 that supports the back surface of the swash plate 10 through an angular contact via a ring 11 in order to hold the swash plate 10 in a state inclined at a certain angle with respect to the axis of the pump cylinder 7. Plate holder l 2' is input cylinder shaft 5
is fitted to the inner wall of the Further, the outer end of the input cylinder shaft 5 has the above-mentioned
A driven gear 2b of the secondary reduction gear 2 is attached via a torque damper.

Thus, when the input cylinder shaft 5 rotates, the pump swash plate 10 can sequentially reciprocate the pump plungers 9, 9, . . . to repeat the suction and discharge strokes.

On the other hand, the hydraulic motor M includes a motor cylinder 17 disposed on the same axis as the pump cylinder 7 and to the left thereof, and an annular array of cylinder holes 8° 8 provided in the motor cylinder 17 so as to surround its axis. The same number of cylinders as...
8.18... Motor plunger sliding inside 19.1
9... and these motor plungers 19.19...
a motor swash plate 20 whose front surface abuts the outer end of the motor swash plate 20; a motor swash plate holder 22 which supports the back surface of the motor swash plate 20 via a tapered roller bearing 21; The motor swash plate anchor 23 is fixed to the casing 4 with bolts 27.

Each cylinder hole 18 is formed to have a larger diameter than the cylinder hole 8, thereby increasing the maximum capacity of the hydraulic motor M to the hydraulic pump P.
The capacity is set to be sufficiently larger than the capacity of the engine, so that a large reduction ratio can be obtained.

The motor swash plate holder 22 is integrally provided with a pair of semi-cylindrical trunnion shafts 22a and 22b at both ends, which are arranged on the trunnion axis 0□ orthogonal to the axis of the motor cylinder 17, and both trunnion shafts 22a.

22b is a bearing hole 23 formed in the motor swash plate anchor 23
a and the bearing recess 23b, respectively, so as to be rotatable. In addition, a motor swash plate holder 22 and a motor swash plate anchor 2
The opposing surfaces f1 and f2 of No. 3 that come into contact with each other are formed into spherical surfaces centered on the intersection of the axis of the motor cylinder 17 and the trunnion axis 0□. Therefore, the eta swash plate holder 2
2 can rotate around the trunnion axis 0□ while receiving an alignment action from the motor swash plate anchor 23.

A cylindrical cylinder holder 24 extending to the right is integrally connected to the motor swash plate anchor 23, and the outer peripheral surface of the motor cylinder 17 is rotatably supported by the cylinder holder 24 via a ball bearing 25. be done.

As shown in FIGS. 8 to 10, an operating lever 26 is fixed to one trunnion shaft 22a, and an electric motor 29 capable of forward and reverse rotation is connected to this operating lever 26 via a ball nut mechanism 28.

The ball nut mechanism 28 includes a screw shaft 30 and a screw shaft 30.
The output shaft of an electric motor 29 is connected to a screw shaft 30, and a pair of forks 33 and 33 protruding from the outer surface of the nut 32 are actuated. The tip of the lever 26 is connected via a pin 34.

The electric motor 29 is supported by a bracket 35 protruding from the outer surface of the cylinder holder 24, and the screw shaft 30 is supported by a pair of brackets 36 and 37 protruding from the motor swash plate anchor 23 and the outer surface of the cylinder holder 24. It is rotatably supported via ball bearings 38 and 39.

When the screw shaft 30 is rotated in the forward direction by the electric motor 29, the nut 32 moves to the left in FIG. , the motor swash plate 20 can be erected, and if the screw shaft 30 is reversed, the nut 32 will move to the right and the motor swash plate 20 can be tilted to about 1. When the motor cylinder 17 rotates in its tilted state, the plate 20 moves the motor plungers 19, 19, and 19.
...It is possible to sequentially give reciprocating motion to the group and repeat the expansion stroke and contraction stroke.

Again in FIGS. 1 and 2, the pump cylinder 7 and the motor cylinder 17 are integrally connected to each other to constitute a cylinder block B, and this cylinder block B and the output shaft 15 passing through its center are connected by a spline. join 40
be done.

This output shaft 15 has a driven gear 2b of the primary reduction gear 2.
A driving gear 3a of the secondary reduction gear 3 is integrally formed adjacent to the . The meshing portion between the driving gear 2a and the driven gear 2b in the primary reduction gear 2 and the meshing portion between the driving gear 3a and the driven gear 3b in the secondary reduction gear 3 are arranged on opposite sides of the axis of the output shaft 15. Ru.

The left end of the output shaft 15 is supported by the motor swash plate anchor 23 via a tapered roller bearing 41, and a bearing holder 4 supports the inner race of this bearing 41.
2 is fixed to the output shaft 15 by a bolt 43.

Further, the right end of the output shaft 15 includes a ball bearing 44 and a taber roller bearing 45 arranged on both sides of the drive gear 3a.
It is supported by the casing 4 and also supports the input cylinder shaft 5 via.

In order to rotate the pump swash plate 10 synchronously with the pump cylinder 7, the pump swash plate 10 is formed with a spherical recess 10a in which the spherical end 9a of the corresponding pump plunger 9 engages.

Further, in order to rotate the motor swash plate 20 synchronously with the motor cylinder 17, the motor swash plate 20 is formed with a spherical recess 20a into which the spherical end 19a of the corresponding motor plunger 19 engages.

Each of the spherical recesses 10a, 20a is formed with a radius larger than the radius of the corresponding spherical end 9a, 19a, so that the spherical end 9a,
19a is ensured.

Furthermore, as shown in FIG. 11, on the outer peripheral surfaces of the pump cylinder 7 and the motor cylinder 17, there are holes recessed between the respective cylinder holes 8, 8...; 18, 1B... for weight reduction. A number of grooves 46,47 are formed.

In FIG. 1, FIG. 2, and FIG. , annular inner oil passage 52 and outer oil passage 53 theory arranged concentrically around the output shaft 15, both oil passages 52, 5
Cylinder holes 8.8... and 18.18... radially pass through the annular partition wall between the holes 8.8 and 18.18 and the outer peripheral wall of the outer oil passage 53.
and the same number of first valve holes 54, 54... and second valve holes 55, 55... and adjacent cylinder holes 8, 8...
and the pump ports a, a... which communicate with each other the first valve holes 54, 54..., and the adjacent cylinder holes 18, 18...
. . . and the second valve holes 55, 55, . . . and a large number of motor ports b that communicate with each other.

b... are provided. Inner oil passage 52 and outer oil passage 5
3 corresponds to the low pressure oil passage and the high pressure oil passage of the present invention, respectively.

The inner oil passage 52 is formed as an annular groove on the inner peripheral surface of the cylinder block B, and its open surface is closed by the outer peripheral surface of the output shaft 15.

The first valve holes 54, 54... are provided with spool-type first distribution valves 56, 56..., and the second valve holes 55, 55...
... also has a spool-type second distribution valve 57°57.
... are rubbed together. and a first distribution valve 56.
At the outer ends of the second distribution valves 57, 57, there is a first eccentric ring 58 surrounding them, and at the outer ends of the second distribution valves 57, 57, there are second eccentric wheels 59 surrounding the pole bearings 60, 61, respectively.
The outer ends of the first distribution valves 56, 56... are mutually engaged by a first forcing ring 62 in concentric relation with the first eccentric ring 56, in order to force their engagement. The outer ends of the second distribution valves 57, 57... are connected to the second eccentric wheel 59.
They are interconnected by a second forcing ring 63 that is concentric with the two.

As shown in FIG. 3, the first eccentric wheel 58 is configured to swing between a clutch-on position n and a clutch-off position f.
It is connected to the inner end of the input cylinder shaft 5 via a pivot shaft 64 parallel to the output shaft 15 . At the clutch-on position n, this first eccentric wheel 58 occupies a position eccentric by a predetermined distance ε1 from the center of the output shaft 15 along the trunnion axis 0□, and at the clutch-off position if, from the center of the output shaft 15. It occupies a position eccentric by a distance ε2 larger than the eccentricity ε1, and the clutch-off position f is such that the inner peripheral edge of the first eccentric ring 58 is connected to the first stopper 65 protruding from the inner end surface of the input cylinder shaft 5.
The clutch-on position n is determined by the contact with the second stopper 6, in which the inward protrusion 67 of the first eccentric wheel 58 protrudes from the inner end surface of the human-powered cylinder shaft 5 on the opposite side to the first stopper 65.
6, respectively.

In addition, spring receiving pieces 68 and 69 are projectingly provided on the first eccentric wheel 58 and the input cylinder shaft 5 and are opposed to each other in the circumferential direction on the opposite side to the pivot shaft 64, and a clutch spring 70 is compressed between these pieces.
The spring force moves the first eccentric wheel 58 to the clutch off position f
is biased in the direction of .

Further, the first eccentric wheel 58 is integrally formed with a weight 71 that exerts a centrifugal force in the direction of the clutch-on position n when the first eccentric wheel 58 rotates.

Furthermore, in order to prevent the clutch spring 70 from coming off, an eaves 72 is formed on the first eccentric wheel 58 so as to cover the spring 70 and to be connected to the spring receiving piece 68 .

Furthermore, the first eccentric wheel 58 and the input cylinder shaft 5 have a first
The guide groove 73 and the guide protrusion 74 that slidably engage with each other in order to restrict the swing path of the eccentric ring 58 around the pivot shaft 64
, are provided on the opposite side of the IIX axis 64 (see FIGS. 3 and 4).

As shown in FIG. 5, when the first eccentric wheel 58 occupies the clutch-on position n and relative rotation occurs between the input cylinder shaft 5 and the pump cylinder 7, each first distribution valve 56 The first eccentric wheel 58 reciprocates between the radially inner position and the outer position of the pump cylinder 7 in the first valve hole 54 with a stroke of twice the eccentricity ε1. and,
In the discharge region of the hydraulic pump P, the first distribution valve 56 moves to the inner position side to communicate the corresponding pump port a with the outer oil passage 53 and disconnect it from the inner oil passage 52.

In addition, in the suction region S, the first distribution valve 56 moves to the outer position side to bring the corresponding pump port (a) into communication with the inner oil passage 52 and to disconnect it from the outer oil passage 53.

Moreover, when the first eccentric wheel 58 occupies the clutch-off position f (see FIG. 6), when relative rotation occurs between the input cylinder shaft 5 and the pump cylinder 7, each first distribution valve 56 58, the pump cylinder 7 is reciprocated between the radially inner position and the outer position with a stroke of twice the eccentricity amount ε2 in the first valve hole 54, and the first distribution is performed at the inner and outer positions. Valve 56 provides direct communication between inner and outer oil passages 52 and 53.

On the other hand, as shown in FIG.
3. Said cylinder holder 24 so as to occupy an eccentric position.
are combined into one.

When the motor cylinder 17 rotates, each of the second distribution valves 57 moves in the radial direction of the motor cylinder 17 at the second valve hole 55 by a distance twice the eccentricity ε3. It is reciprocated between the outer position and the outer position. Then, in the expansion request area Ex of the hydraulic motor M, the second distribution valve 57 moves to the inner position side to communicate the corresponding motor motor boat b with the outer oil passage 53 and disconnect it from the inner oil passage 52. do. In addition, in the contraction region sh, the second
The distribution valve 57 moves to the outer position to communicate the corresponding motor boat b with the inner oil passage 52 and the outer oil passage 5.
3 and disconnect.

In the above configuration, the input cylinder shaft 5 of the hydraulic pump P is driven from the engine E via the primary reduction gear 2, and the pump swash plate 10 alternately applies discharge and suction strokes to the pump plungers 9° 9... Each pump plunger 9 pumps hydraulic oil from the cylinder hole 8 to the outer oil passage 53 while passing through the discharge area, and while passing through the suction area S,
Hydraulic oil is sucked into the cylinder hole 8 from the inner oil passage 52.

By the way, when the engine E is idling, the rotational speed of the input cylinder shaft 5 is low, and the centrifugal force exerted by the weight 71 of the first eccentric wheel 58 that rotates together with the input cylinder shaft 5 is weak. is held at the clutch off position f by the clutch spring 70.

Therefore, since the first distribution valve 56 directly communicates between the inner and outer oil passages 52 and 53 as described above, the cylinder hole 8 accommodates the pump plunger 9 for the suction stroke and the pump plunger 9 for the discharge stroke. The cylinder hole 8 is short-circuited via the inner and outer oil passages 52 and 53, and no hydraulic pressure is transmitted to the hydraulic motor M.

The centrifugal force of the weight 71 increases with the increase in rotation of the engine E and therefore the rotation of the input cylinder shaft 5, and when the centrifugal force exceeds the set load of the clutch spring 70, the first eccentric wheel 58 moves to the clutch-on position n. It then moves around the axis 64.

When the first eccentric wheel 58 reaches the clutch-on position n, as described above, the first distribution valve 56 connects the pump port a in the suction region S to the inner oil passage 52 and disconnects it from the outer oil passage 53. Since the pump port a is communicated with the outer oil passage 53 in the discharge area and disconnected from the inner oil passage 52, the hydraulic oil forced into the outer oil passage 53 by the pump plunger 9 during the discharge stroke is transferred to the swelling area of the hydraulic motor M. Hydraulic oil is supplied to the cylinder hole 18 of the motor plunger 19 located at Ex, while the hydraulic oil is discharged from the cylinder hole 18 to the inner oil passage 52 by the motor plunger 19 located at the contraction region sh.

During this period, the pump cylinder 7 receives reaction torque from the pump swash plate 10 via the pump plunger 9 in the discharge stroke, and the motor cylinder 17 receives the reaction torque from the pump plunger 1 in the expansion stroke.
The cylinder block B is rotated by the sum of the reaction torque received from the motor swash plate 20 via the motor swash plate 9 , and the rotational torque is transmitted from the output shaft 15 to the secondary reduction gear 3 .

While the first eccentric wheel 5B passes between the clutch-off position f and the clutch-on position n, a part of the hydraulic oil discharged from the hydraulic pump P is short-circuited to the suction side, and the remainder is supplied to the hydraulic motor M. Therefore, from the hydraulic pump P to the hydraulic motor M
The clutch is in a half-clutch state with moderately suppressed hydraulic power transmission to the clutch. Thus, as the rotation of the engine E increases, hydraulic power transmission from the hydraulic pump P to the hydraulic motor M is automatically started, and the vehicle starts smoothly.

The gear ratio of the output shaft 31 to the input cylinder shaft 5 can be determined by the following equation.

Capacity of Hydraulic Pump P Therefore, if the capacity of hydraulic motor M is changed to a value consisting of zero, the transmission ratio can be changed to a required value consisting of one. Moreover, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 19, 1. By tilting the motor swash plate 20 from an upright position to an inclined position, the gear ratio can be controlled steplessly up to a value of 1.

During operation of the transmission T, the pump swash plate 10 receives thrust loads in opposite directions from the pump plungers 9, 9... groups, and the motor swash plate 20 receives thrust loads in opposite directions from the motor plungers 19, 19... groups. The thrust load that the swash plate 10 receives is the angular contact bearing 11, the pump swash plate holder 12, the input cylinder shaft 5, and the tapered roller bearing 4.
The thrust load that the motor swash plate 20 receives is supported by the output shaft 15 via the drive gear 3a and the drive gear 3a. and is supported by the output shaft 15 via the contactor 43. Therefore, the thrust load merely causes a tensile stress on the output shaft 15 and does not act on the casing 4 supporting the shaft 15 at all.

In this case, the motor swash plate holder 22 supports the motor swash plate 20 on the front side via the tapered roller bearing 21, and is supported on the back side by the motor swash plate anchor 23.
Motor plunger 19. Motor swash plate 2 from group 19.
Even if a thrust load is applied through 0, no deflection occurs. In addition, since the motor swash plate holder 22 and the motor swash plate anchor 23 face spherical surfaces f, , f centered at the intersection of the axis of the motor cylinder 17 and the trunnion axis 0□, the interaction between these spherical surfaces As a result, the motor swash plate holder 22 exhibits an alignment function. As a result, the motor swash plate holder 22 can smoothly rotate around the trunnion axis Ot, and the inclination angle of the motor swash plate 20 can be easily controlled. At this time, due to the engagement between the trunnion shafts 22al and 22b of the motor swash plate holders 2, 2 and the bearing hole 23a and bearing recess 23b of the motor swash plate anchor 23, the axis around the trunnion axis Ot of the motor swash plate holder 22 is Rotation is prevented.

Further, the motor swash plate anchor 23 having a concave spherical surface f becomes thicker from the center toward the periphery and has high rigidity.
It can withstand a large load from 1.

Further, the driven gear 2b and the driving gear 3a provided on the input cylinder shaft 5 and the output shaft 15, respectively, which are concentrically arranged, are arranged adjacent to each other in the axial direction, and the driving gear 2a and the driving gear 3a mesh with the driven gear 2b. Since the driven gear 3b that meshes with the driven gear 3b and the driven gear 3b are arranged on opposite sides of the axis of the output shaft 15, large radial loads are applied to the driven gear 2b and the driving gear 3a from the mating gears 2a and 3b, respectively, during transmission. However, since the directions of both loads are opposite to each other and the distance between the points of application of both loads is extremely small, the bending moment and swinging moment applied to the output shaft 15 due to both loads are extremely small. As a result, it is possible to reduce the load on the bearings 41 and 44 that support both ends of the output shaft 15 and extend their life.

Again in FIGS. 1, 2, and 5, a central oil passage 80 with one end closed is bored in the center of the output shaft 15, and this oil passage 80 is connected to a supply pump 81 for primary and secondary oil. Hydraulic oil is supplied through oil filters 82 and 83. The replenishment pump 81 is driven from the crankshaft 1 via a transmission device (not shown), and sucks oil from an oil reservoir 84 provided at the bottom of the casing 4 . The primary oil filter 82 is attached to the right side wall of the casing 4 facing the entrance of the central oil passage 80, and the secondary oil filter 83 is attached to the central oil passage 80 from the entrance to the center thereof.

A valve cylinder 85 adjacent to the inner end of the secondary oil filter 83 is fitted into the center of the output shaft 15 so as to cross the central oil passage 80 and have both ends facing the inner oil passage 52 . This valve cylinder 8
5, a cross-shaped horizontal hole 86 opening into the central oil passage 80, and a pair of lateral holes 86 facing each other across the horizontal hole 86 and communicating the horizontal hole 86 with the inner oil passage 52. valve chamber 8
7.87, and each valve chamber 87 accommodates a first check valve 88 that prevents backflow of oil from the inner oil passage 52 to the central oil passage 80.

The inner peripheral surface of the cylinder block B is opposed to both end surfaces of the valve cylinder 85 with a small gap (see FIG. 1), thereby preventing the valve cylinder 85 from being pulled out from the output shaft 15.

In addition, a valve cylinder 8 is provided on the output shaft 15 and the cylinder block B.
A series of replenishment oil passages 9o are provided that connect the central oil passage 80 upstream from the outer oil passage 53 and the outer oil passage 53. A second check valve 91 is interposed to prevent backflow of.

During normal load operation in which the hydraulic motor M is hydraulically driven from the hydraulic pump P, the pressure in the inner oil passage 52 on the low pressure side increases to the pressure in the central oil passage 80 due to oil leakage from the hydraulic closed circuit between the two. When the oil pressure decreases below this level, the first check valves 8B, 8B open and the inner oil passage 52 is replenished with hydraulic oil from the central oil passage 8o. On the other hand, at this time, the hydraulic oil in the outer oil passage 53 on the high pressure side is prevented from flowing into the central oil passage 80 by the second check valve 91 .

Furthermore, during reverse load operation, that is, during engine braking, the hydraulic motor M performs a pumping action, and the hydraulic pump P performs a motor action, thus changing the outer oil passage 53 to low pressure and the inner oil passage 52 to high pressure. Therefore, if the pressure in the outer oil passage 53 decreases due to oil leakage due to the pressure in the central oil passage 80, the second check valve 91 opens and hydraulic oil is replenished from the central oil passage 80 to the outer oil passage 53, and the inner From oil passage 52 to center oil passage 8
The first check valves 8B and 88 prevent the hydraulic oil from flowing out to the valve 0.

C1 Effects of the Invention As described above, according to the present invention, a clutch spring that biases the eccentric wheel toward the clutch-off position is connected to the eccentric wheel, and the eccentric wheel is clutched against the spring force of the clutch spring. Since a weight is attached that can exert centrifugal force to move it toward the on position, the position of the eccentric wheel can be controlled automatically according to the rotational speed of the input member by the centrifugal action of the weight, and the hydraulic pump The shut-off state and hydraulic transmission state between the hydraulic motor and the hydraulic motor can be accurately obtained regardless of whether the operator is skilled or not. Moreover, since the weight is attached to the eccentric wheel, there is no need for a special interlocking mechanism for transmitting the centrifugal force of the weight to the eccentric wheel, and the structure is extremely simple.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional plan view of a power unit for a motorcycle equipped with the hydrostatic continuously variable transmission of the present invention, which is installed in the power transmission system of a motorcycle, and FIG. Figures 3 and 3 are cross-sectional views taken along lines
6 is a sectional view similar to FIG. 5, showing the eccentric wheel in the clutch-off position, and FIG. ■ Line cross section, No. 8
The figure is a view taken in the direction of the ■ arrow in Figure 2, Figure 9 is a sectional view taken along the line IX--■ in Figure 8, Figure 10 is an exploded perspective view of the surrounding area of the motor swash plate holder, and Figure 11 is a perspective view of the cylinder block It is. a...Pump port, b...Motor port, [...
・Clutch off position, n...Clutch on position, M
...Hydraulic motor, P...Hydraulic pump, T...Continuously variable transmission, 5...Input sleeve as human power member, 7...
Pump cylinder, 8... Cylinder hole, 9... Pump plunger, 10... Pump swash plate, 15... Output shaft, 17... Motor cylinder, 1... Cylinder hole,
19...Motor plunger, 20 Motor swash plate, 52...
... Inner oil passage as a low pressure oil passage, 53... Outer oil passage as a high pressure oil passage, 56... Distribution valve, 58... Eccentric wheel, 70... Clutch spring, 71... Heavy Weight pole 9komi 2b Fig. 8

Claims (1)

[Claims] A pump cylinder of a swash plate type hydraulic pump and a motor cylinder of a swash plate type hydraulic motor are coaxially and integrally connected to each other,
A circular high-pressure oil passage that communicates with the motor port that exists in the expansion stroke area of the hydraulic motor and an annular low-pressure oil passage that communicates with the motor port that exists in the contraction stroke area of the hydraulic motor are concentrically connected between the pump cylinder and the motor cylinder. and a plurality of distributing valves are arranged radially and reciprocating between radially outer and inner positions to alternately communicate the plurality of pump ports of the hydraulic pump with the high-pressure oil passage and the low-pressure oil passage. and an eccentric wheel circumscribing these distribution valves is connected to an input member of the hydraulic pump so as to be movable between a clutch-off position and a clutch-on position, and in a first eccentric position of the eccentric wheel, the discharge of the hydraulic pump is controlled. The distribution valve is controlled to communicate the pump port existing in the stroke region to the high pressure oil passage, the pump port existing in the suction stroke area to the low pressure oil passage, and to short-circuit the hydraulic pump at the second eccentric position. In a hydrostatic continuously variable transmission, a clutch spring that biases the eccentric wheel toward the clutch-off position is connected to the eccentric wheel, and a clutch spring that biases the eccentric wheel toward the clutch-on position is connected against the spring force of the clutch spring. A hydrostatic continuously variable transmission characterized by being equipped with a weight that can exert centrifugal force to move the object.