JPS62167970A - Continuously variable transmission of static oil pressure type - Google Patents

Abstract

PURPOSE:To simplify a construction and reduce a cost, by utilizing the thrust load of the plungers of a hydraulic motor to optionally adjust the angle of the swash plate of the motor. CONSTITUTION:An inner annular oil chamber 40 and an outer annular oil chamber 41, which are concentrically located around an output shaft 25, a first valve hole 42 and a second valve hole 43 are provided in a cylinder block B. A first distribution valve 45 and a second distribution valve 46 are slidably fitted in the first valve hole 42 and the second valve hole 43, respectively. A first eccentric wheel 47 and a second eccentric wheel 49 are engaged on the outer end of the first distribution valve 45 and that of the second distribution valve 46, respectively. The distribution of the thrust load of motor plungers 19 upon a motor swash plate 20 at the expansion stroke thereof can thus be controlled to optionally adjust the angle of the motor swash plate to obtain a desired ratio of speed change. This results in simplifying a construction and reducing a cost.

Description

Detailed Description of the Invention A8 Objective of the Invention (1) Industrial Application Field The present invention forms a hydraulic closed circuit between a swash plate type hydraulic pump and a swash plate type hydraulic motor, and this hydraulic closed circuit includes: A high-pressure oil passage of the circuit is communicated with a cylinder hole that accommodates a motor plunger on an expansion stroke of the hydraulic motor, and a low-pressure oil passage of the circuit is communicated with a cylinder hole that accommodates a motor plunger on a contraction stroke of the hydraulic motor. A communicating sliding distribution mechanism is provided,
The present invention relates to a hydrostatic continuously variable transmission capable of steplessly changing speed by controlling the capacity of a hydraulic motor by adjusting the angle of a motor swash plate of the hydraulic motor.

(2) Prior Art Conventionally, it has been known to connect a hydraulic servo to a motor swash plate so that the angle of the motor swash plate can be easily adjusted (
(See Special Publication No. 59-38467).

(3) Problems to be Solved by the Invention In the above-mentioned conventional technology, the hydraulic servo motor has a complex structure and is expensive, so it tends to be costly. ·Therefore,
The present invention makes it possible to freely adjust the angle of the motor swash plate by using the thrust load that the motor swash plate receives from a group of motor plungers of a hydraulic motor, thereby making it simple and effective without using an expensive hydraulic servo motor. An object of the present invention is to provide a speed change control device for a hydrostatic transmission.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention changes the thrust load distribution applied to the motor swash plate of the motor plunger group during the expansion stroke to the trunnion axis of the motor swash plate. The first to be equal on both sides
state, and a second state in which the same distribution is biased toward one example of the trunnion axis to apply a moment in the upright direction to the motor swash plate.
and a third state in which the same distribution is biased toward the other side of the trunnion axis to apply a moment in the tilting direction to the motor swash plate.
The first feature is that it is equipped with a speed change control device that controls the distribution mechanism so as to select the state of The first and second oil chambers, which are connected to a piston and are defined between the cylinder and the piston and are opposed to each other with the piston in between, are communicated with each other via a hydraulic conduit filled with oil, and the hydraulic conduit The second feature is that a valve device is interposed to shut off the conduit in conjunction with the first state.

(2) Effect In the first feature of the present invention, if the distribution mechanism is controlled to the first state by the operation of the speed change control device, the thrust load distribution exerted on the motor swash plate of the motor plunger group during the expansion stroke is changed to the motor swash plate. Equal on both sides of the plate trunnion axis, no tilting moment is generated on the motor swashplate, so the motor swashplate can remain in any angular position at that time. Furthermore, if the distribution mechanism is controlled to the second state, the thrust load distribution is biased toward one side of the trunnion axis of the motor swash plate, and a moment is applied to the motor swash plate in the upright direction, so that the motor swash plate cannot be erected. I can do it. Furthermore, if the distribution mechanism is controlled to the third state, the thrust load distribution is biased toward the other side of the trunnion axis of the motor swash plate, and a moment is applied to the motor swash plate in the tilting direction, so that the motor swash plate cannot be tilted. I can do it.

In the second feature of the present invention, in the second and third states, the hydraulic conduit is brought into conduction by the valve device, so that the hydraulic conduit is connected between the first and second oil chambers in conjunction with the tilting of the motor swash plate. As oil flows through the hydraulic conduit, tilting of the motor swashplate is permitted. In addition, in the first state, the hydraulic conduit is shut off by the valve device, so the flow of oil as described above is prevented, and thereby the tilting of the motor swash plate is suppressed, so that the motor swash plate receives no pulsating moment. The motor swash plate can be reliably held at any angular position even when the motor swash plate is bent.

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

First, in FIGS. 1 and 2, the power of the engine E of the motorcycle is sequentially transmitted from the crankshaft 1 to the chain type primary reduction gear 2, the hydrostatic continuously variable transmission T, and the chain type secondary reduction gear I3. The signal is then transmitted to the rear wheels (not shown).

The continuously variable transmission T includes a constant displacement swash plate hydraulic pump P and a variable displacement swash plate hydraulic motor M, and has a crankcase 4 supporting a crankshaft l as a casing.
accommodated in it.

The hydraulic pump P includes a cup-shaped input member 5 integrally equipped with the output sprocket 2a of the primary reduction gear ff2, and a pump that is fitted to the inner peripheral wall of the input member 5 via a needle bearing 6 so as to be relatively rotatable. A cylinder 7, pump plungers 9, 9, . It is composed of a pump swash plate 10 that comes into contact with the outer ends of the pump plungers 9, 9, . . .

Since the pump swash plate IO is orthogonal to the axis of the pump cylinder 7, the pump cylinder 7 is centered around the virtual trunnion axis O1.
The input member 5 has its back side rotatably supported via a thrust roller bearing 1) on the inner end wall of the input member 5 in a posture tilted at a certain angle with respect to the axis of the pump plunger 9. Reciprocating motion can be applied to repeat the suction and discharge strokes.

Incidentally, in order to improve the followability of the pump plunger 9 with respect to the pump swash plate 10, a spring that biases the pump plunger 9 in the expansion direction may be compressed in the cylinder hole 8.

The input member 5 has a thrust roller bearing 1 on its back side.
It is supported by the support cylinder 13 via 2.

On the other hand, the hydraulic motor M includes a moke cylinder 17 disposed on the same axis as the pump cylinder 7 and to the left thereof, and a plurality of odd number cylinder holes arranged in an annular arrangement surrounding the rotation center of the motor cylinder 17. 18. Motor plungers 19, 19... are slid together with 18, 18..., respectively.
, a motor swash plate 20 that comes into contact with the outer ends of these motor plungers 19, 19..., a swash plate holder 22 that supports the back surface of this motor swash plate 20 via a thrust roller bearing 21, and further this swash plate. It is composed of a cup-shaped swash plate anchor 23 that supports the holder 22.

The motor swash plate 20 can be tilted between an upright position perpendicular to the axis of the motor cylinder 17 and an inclined position inclined at an angle. Accompanying motor plunger 19.
19... can be given reciprocating motion to repeat the expansion and contraction strokes.

Incidentally, in order to improve the followability of the motor plunger 19 with respect to the motor swash plate 20, a spring that biases the motor plunger 19 in the extension direction may be compressed in the cylinder hole 18.

The pump cylinder 7 and the motor cylinder 17 constitute an integrated cylinder block B, and the output shaft 25 is passed through the center of the cylinder block B.

Then, the outer end of the motor cylinder 17 is brought into contact with a flange 25a that is integrally formed on the outer periphery of the output shaft 25, and the pump cylinder 7 is spline-fitted to the output shaft 25. By locking the clip 26 to the output shaft 25, the cylinder block B is fixed to the output shaft 25.

The output shaft 25 also passes through the manpower member 5 and rotatably supports the member 5 via a needle bearing 27.

The support cylinder 13 has a key 28 on the outer periphery of the right end of the output shaft 25.
It is fitted through and fixed with a Nand 30. The right end portion of the output shaft is rotatably supported by the crankcase 4 via the support tube 13 and roller bearing 31.

Further, the output shaft 25 is connected to the motor swash plate 20 and the swash plate holder 22.
and a thrust roller bearing 3 that passes through the center of the swash plate anchor 23, and a thrust roller bearing 3 that connects the back surface of the swash plate anchor 23 to the left end thereof.
A support cylinder 33' supported through 1. The left end portion of the output shaft 25 is rotatably supported by the crankcase 4 via the support tube 33 and roller bearing 35.

A hemispherical centering body 36 that engages with the inner circumferential surface of the pump swash plate 10 so as to be tiltable in all directions is slidably fitted onto the output shaft 25 by a spline. This centering body 36 presses the pump slant Fi 10 against the thrust roller bearing 1) by the force of the plurality of disc springs 38, and thereby the pump swash plate l
It always gives an aligning effect to O.

Further, a hemispherical centering body 37 that engages with the inner circumferential surface of the motor swash plate 20 so as to be tiltable in all directions is slidably fitted onto the output shaft 25 by a spline. This centering body 37 presses the motor swash plate 20 against the thrust roller bearing 21 by the force of the plurality of disc springs 39, thereby constantly applying an alignment action to the motor swash plate 20.

The centering action of each swash plate 10.20 is strengthened, and the pump swash plate 10 and pump plungers 9.9... groups, the motor swash plate 20 and motor plungers 19.19...

In order to prevent rotational slippage between each group, each category 1)
0.20 has a corresponding plunger 9. Spherical recesses 10a, 20a that engage the spherical ends 9°a, 19a of 19
are formed respectively. At that time, the spherical recesses 10a, 20
a at any rotational position of the swash plate 10.20,
The radius of curvature is set larger than that of the spherical ends 9a, 19a so as to ensure proper engagement with the spherical ends 9a, 19a.

A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M as follows.

The cylinder block B includes cylinder holes 8, 8,... groups of the pump cylinder 7 and cylinder holes 1 of the motor cylinder 17.
8.18...An annular inner oil chamber 40 and outer oil chamber 41 arranged concentrically around the output shaft 25 between the groups
and the same number of first valve holes 42 as the cylinder holes 8.8, 18, 18, . .4
2... and the second valve holes 43, 43... and the adjacent cylinder holes 8, 8... and the first valve holes 42, 42..., a large number of pump boats a, a..., adjacent cylinder holes 18°18... and second valve holes 43, 43
A large number of motor boats b, b... which communicate with each other.
・And is provided.

At that time, the inner oil chamber 40 is formed between the opposing peripheral surfaces of the cylinder block B and the output shaft 25, and the outer oil chamber 41 is fitted and welded to the cylinder block B and its outer periphery. It is formed between the circumferential surfaces facing the sleeve 44. Here, the inner and outer oil chambers 40, 41 correspond to the low pressure and high pressure oil passages of the present invention.

A first distribution valve 45°4 is provided in the first valve holes 42, 42...
5, and second distribution valves 46, 46, . . . are slidably fitted into the second valve holes 43, 43, .

Each of the first distribution valves 45 is formed in a spool shape as shown in FIG. communicates with the inner oil chamber 40, communicates the corresponding cylinder hole 8 only with the outer oil chamber 41, and communicates with the first valve hole 4.
2, the corresponding pump bow 1-a is communicated with the inner oil chamber 40 and disconnected from the outer oil chamber 41, and the corresponding cylinder hole 8 is communicated only with the inner oil chamber 40.

In order to impart such a movement to each first distribution valve 45, a first eccentric 47 is engaged around the group of first distribution valves 45, 45... at their outer ends; A follow-up width 47' that is concentric with the first distribution valve 45.
... (see Fig. 3), the following width 47'
is molded from W4 wire, and the first distribution valve 45.45.
... in the direction of engagement with the first eccentric wheel 47. Note that this follow-up width 47' may be provided with one cut in order to absorb manufacturing errors in its diameter.

The first eccentric wheel 47 is rotatably supported by the input member 5 via a ball bearing 48, and as shown in FIG. It is placed at a position eccentric from the center by a certain distance ε1. Therefore, when relative rotation occurs between the input member 5 and the pump cylinder 7, each first distribution valve 45
It reciprocates between the outer position and the inner position within the valve hole 42 with a stroke of twice the eccentricity ε of the first eccentric 47.

Each of the second distribution valves 46 is formed in a spool shape, and when it occupies a position radially outward of the second valve hole 43, it communicates the corresponding motor boat b with the outer oil chamber 41 and the inner oil chamber 40. When the corresponding cylinder hole 18 is placed in a radially inward position of the second valve hole 43, the corresponding motor boat b is communicated with the inner oil chamber 40, and the corresponding cylinder hole 18 is communicated only with the outer oil chamber 41. By disconnecting the outer oil chamber 4I, communicating the corresponding cylinder hole 18 only with the inner oil chamber 40, and occupying the central position between the above two positions, the corresponding motor boat 6 is connected to the inner and outer oil chambers 40, 41. Make it impossible to communicate with any of the following.

As shown in FIGS. 5 and 10, the second distribution valve 46 has a notch 46b cut out on one side of the outer peripheral surface, and this notch 46b.
6b has a horizontal hole 46c that constantly communicates with the motor boat b, and the motor port b and the inner and outer oil chambers 4 are connected by the liquid valve 46.
0, 41, whether the notch 46a faces the inner oil chamber 40 or the outer oil chamber 41, or both oil chambers 40, 41.
Determined by whether it is hidden within the partition wall between.

In order to impart such a movement to each second distribution valve 46, a second eccentric 49 is engaged around the group of second distribution valves 46, 46, at their outer ends, and A follower shaft 49' concentric with the second distribution valves 46, 46... is disposed inside the group and engages the engagement grooves 46a, 46a, 46a, 46a, 46a, 46a, 46a, 46a, etc.
..., and this engagement prevents rotation of each second distribution valve 46 (see FIG. 5). The follower shaft 49' is formed from steel wire, and the second distribution valve 46, 46...
The second eccentric shaft 49 is disposed in such a way as to be ejected in the direction of engagement with the second eccentric shaft 49.

Incidentally, this follow-up shaft 49' may also be provided with one cut like the follow-up shaft 47'.

Here, the second distribution valve 46, 46... and the second eccentric wheel 4
9 constitutes the distribution mechanism of the present invention.

The second eccentric shaft 49 is connected to the motor swash plate 2 as shown in FIG.
0 tilting axis, i.e. trunnion axis &? A first eccentric position e that is eccentric by a certain distance ε2 from the center of the output shaft 25 along l o z, and a first eccentric position e that is eccentric from the center of the output shaft 25 along the
2, a third eccentric position g whose center is slightly shifted from the first eccentric position e to the other side of the tranio axis o2, and which is concentric with the output shaft 25. The concentricity value zh is controlled to be .

Thus, the second eccentric wheel 49 moves from the first eccentric position 71e to the third eccentric position 71e.
When the motor cylinder 17 rotates when occupying the eccentric position g, each second distribution valve 46 moves within its valve hole 43 by a distance stroke of twice the eccentricity ε2 of the second eccentric wheel 49. It reciprocates between the inner position and the inner position, and the concentric value H
h, all the second distribution valves 49, 49, . . . are kept at the center position due to the rotation of the motor cylinder 17.

As shown in FIG. 2, at both ends of the swash plate holder 22,
A pair of upper and lower trunnion shafts 80.80' aligned on the trunnion axis 02 of the motor swash plate 20 are integrally provided, and these trunnion shafts 80.80' are connected to the needle bearing 81.
and is rotatably supported by the swash plate anchor 23 via roller bearings 81', respectively. In other words, the trunnion axis 0□ is defined by these trunnion axes 80, 80'.

The swash plate anchor 23 is supported on the outer periphery of the motor cylinder 17 via a needle bearing 78, and is connected to the crankcase 4 via one or a pair of positioning pins 79 so as not to rotate around the output shaft 25. be done.

In the above configuration, when the second eccentric shaft 49 occupies the first eccentric position e, when the input member 5 of the hydraulic pump P is rotated from the one-region coupling r12, the pump swash plate 10 causes the pump plungers 9, 9, . . . The first distribution valve 45 adjacent to the pump plunger 9 which is alternately given suction and discharge strokes and which enters the suction stroke is connected to the first eccentric wheel 47 and the follower shaft 47'.
The first distribution valve 45 adjacent to the pump plunger 9 entering the discharge stroke is actuated to the outer position by the cooperation of the first eccentric 47 and the trailing width 47'. Therefore, each pump plunger 9 sucks hydraulic oil from the inner oil chamber 40 into the cylinder hole 8 during the suction stroke, and pumps the hydraulic oil from the cylinder hole 8 to the outer oil chamber 41 during the discharge stroke.

The high-pressure hydraulic oil sent to the outer oil chamber 41 enters the second cylinder hole 18 that accommodates the motor plunger 19 in the expansion stroke.
Hydraulic oil in the cylinder bore 18 accommodating the motor plunger 19 on the retraction stroke is fed through the second distribution valve 46 which is controlled to an outward position by the eccentric shaft 49 and the follower shaft 49'. The oil is discharged into the inner oil chamber 40 via the second distribution valve 46 which is controlled to the inner position by the eccentric wheel 49 and the follower shaft 49'.

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 9, and the rotational torque is transmitted from the output shaft 25 to the secondary reduction gear 3.

In this case, the gear ratio of the output shaft 25 to the input member 5 is given 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.

By the way, the capacity of the hydraulic motor M is the motor plunger 19.
Therefore, 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 such operation of the hydraulic pump P and the hydraulic motor M, the pump swash plate 10 moves from the pump plungers 9, 9...
Also, the motor swash plate 20 has motor plungers 19, 19...
・Each group receives a thrust load in the opposite direction,
The thrust load that the pump swash plate 10 receives is transferred to the output shaft 25 via the thrust roller bearing 1), the input member 5, the thrust roller bearing 12, the support tube 13, and the nut 30.
The thrust load received by the motor swash plate 20 is also applied to the output shaft 25 via the thrust roller bearing 21, swash plate holder 22, swash plate anchor 23, thrust roller bearing 32, support cylinder 33, sprocket 3a, and nut 34. supported by. Therefore, the thrust load merely causes tensile stress on the output shaft 25 and does not act on the crankcase 4 supporting the shaft 25 at all.

By the way, when the second eccentric wheel 49 occupies the first eccentric position e, as shown in FIG.
. . ., there are the same number on average on both sides of the trunnion axis 0□ that connect the high-pressure outer chamber 41 to the motor boat b, so the motor plunger 19.1 in the expansion stroke
The thrust load distribution exerted on the motor swash plate 20 of group 9 is on average equal on both sides of the trunnion axis 0□ (ie, α-β), as shown by Ae in FIG. 5A. Therefore, depending on such thrust load distribution, no tilting moment is generated in the motor swash plate 20 around the trunnion axis Ot, but when the second eccentric 46 occupies the second eccentric position f, as shown in FIG. Of the second distribution valves 46, 46...
Since the number of components that communicate the high-pressure outer chamber 41 with the motor port (b) is greater on the left side than on the right side of the trunnion axis 0□, the motor plunger 19 during the expansion stroke
．． The thrust load distribution exerted on the motor swash plate 20 of the 19... group is determined by the trunnion axis O as shown by Af in FIG. 6A.
The left side of x is wider than the right side (that is, α>β).

Therefore, an upright moment Mf (see Fig. 1) around the trunnion axis 0□ acts on the motor swash plate 20,
This moment M'' causes the motor swash plate 20 to rotate in the upright direction.

On the contrary, the second eccentric position 49 is at the third eccentric position g.
, as shown in FIG. 7, a large number of second distribution valves 46.
46..., the high pressure outer chamber 41 is connected to the motor boat b.
Since the number of parts connected to the right side of the trunnion axis 02 is greater than the number of parts connected to the left side of the trunnion axis 02, the expansion stroke motor plunger 19, the motor swash plate 20 of the group 19...
As shown by Ag in FIG. 7A, the distribution of the thrust load exerted on the trunnion axis 02 is wider on the right side than on the left side of the trunnion axis 02 (that is, α and β). Therefore, a tilting moment Mg (see FIG. 1) around the trunnion axis Ot acts on the motor swash plate 20, and the motor swash plate 20 is tilted by this moment Mg.

In this way, the second eccentric wheel 49 is moved to the first to third eccentric positions e.
-g, the second eccentric wheel 49 is connected to the following speed change control device C.

That is, in FIGS. 2 and 5, the second eccentric ring 49 is rotatably supported by an operating ring 52 via a ball bearing 50, and the operating ring 52 supports the second eccentric ring 49 in a manner that allows the second eccentric ring 49 to rotate freely. A pivot 53 disposed perpendicular to the trunnion axis 0□ so as to be able to swing from position f to third eccentric position tg.
The lower part is supported by a support member 54 via.

A connecting hole 55 is provided in the upper part of the operating ring 52, and a bell crank 5 is provided in the connecting hole 55 for swinging the second eccentric wheel 49 from the first eccentric position f to the third eccentric position g.
6 is engaged. As shown in FIG. 2, the bell crank 56 includes a rotating shaft 56c supported by the crankcase 4 via a bearing 51, and an inner lever 56a fixed to the rotating shaft 56C within the crankcase 4. The outer lever 5 is fixed to this Nichido shaft 56C outside the crankcase 4.
6b, and the tip of the inner lever 56a is inserted into the connecting hole 55.

At the tip of the outer lever 56b, as shown in FIG. 12, a pair of opposing first and second electromagnetic actuators 57. ．．
57°2 operating rods 5B, 5B□ are connected to sandwich the lever 56b. First and second electromagnetic actuators 57. ．．
57□ is the operating rod 58, . 58 □ Movable iron core 59. ．． 592 and this movable iron core 59. ．． Solenoid 60 surrounding 59□. ．． 60t and this solenoid 60, . a common actuator body 61 carrying 60□;
Return springs 62., which urge the movable cores 591.59g towards the outer levers 56b, ie towards the inoperative position, respectively. ．． 62□, and the actuator main body 61 is fixed in place in the crankcase 4.

Therefore, the solenoids 60 of both electromagnetic actuators 57□, 57□
．． ．． 602 are both demagnetized, both operating rods 58. ，
58□ is a double return spring 62. ．． 622 maintains the bell crank 56 in the neutral position, which causes the operating ring 52 to
The second eccentricity 49 can be controlled to the first eccentric position e via.

Furthermore, if only the solenoid 601 of the first electromagnetic actuator 57.0 or the solenoid 60□ of the second electromagnetic actuator 57.0 is excited, the corresponding operating rod 58. or outside lever 5 of 58□
6b, the bell crank 56 is swung from the neutral position counterclockwise or clockwise in FIG.
The eccentric position can be controlled to the eccentric position g or the second eccentric position Hr.

In this case, the second electromagnetic actuator 57□ or the first electromagnetic actuator 57. In this case, as the bell crank 56 swings as described above, a further backward shift is applied from the normal inoperative position.

A positioning notch 96 formed on the lower surface of the outer lever 56b to provide moderation to the neutral position of the bell crank 56.
The spring 9 is housed in the housing hole 99 of the actuator body 61.
A pawl 97 that is biased to protrude by 8 is resiliently engaged.

Meanwhile, a swash plate stabilizing device S is connected to the upper trunnion shaft 80. This swash plate stabilizing device S includes a cylinder 84 fixed in place on the crankcase 4 and a piston 85 slidably engaged with the cylinder 84. A window 86 is formed in the side wall of the cylinder 84, and a connection hole 87 is formed in the center of the piston 85, passing through it laterally and facing the window 86. A control lever 82 is engaged with the connecting hole 87 through the window 86 and is adapted to slide the piston 85 in response to rotation of the trunnion shaft 80.

As shown in FIG. 12, the maximum tilt position and upright position of the motor swash plate 20 are determined by the upper and lower movement ratios of the piston 85, and there is a gap between the piston 85 and the lower end wall of the cylinder 84. The first oil chamber 88 is connected to the piston 85 and the cylinder 8.
A second oil chamber 89 is defined between the upper end wall of 4, and
A return spring 90 is compressed in the first oil chamber 88 and urges the piston 85 toward the second oil chamber 89 .

The first and second oil chambers 88 and 89 communicate with each other via a hydraulic conduit 92 filled with oil.
First and second check valves 931.93□ are interposed in series in the middle. These check valves 93+ and 93t constitute the valve device of the present invention.

First check valve 93. The second check valve 93□ allows oil to flow from the first oil chamber 88 to the second oil chamber 89 through the hydraulic conduit 92 and prevents the reverse flow. On the contrary, the oil is allowed to flow from the second oil chamber 89 toward the first oil chamber 88, and its reverse flow is prevented. Moreover, the first check valve 931 is connected to the second electromagnetic actuator 6
The second check valve 93□ is opened by further retraction of the operating rod 61g of the 02 from the normal inoperative position, and the second check valve 93□ is connected to the first degree electromagnetic actuator 60. The valves are disposed at both ends of the actuator body 64, respectively, so that the valves are forcibly opened by further retraction of the actuating rods 61) from the normal inoperative position.

Therefore, in order to tilt the motor swash plate 20, the first electromagnetic actuator 60. If only one check valve is energized, the first check valve 93° is forcibly opened due to the backward movement of the other operating rod 582 as the operating rod 581 moves forward. The piston 85 moves upward,
The oil in the second oil chamber 89 is transferred to the first oil chamber 88 via the hydraulic conduit 92 (see FIG. 12), and the tilting operation of the motor swash plate 20 is permitted. On the contrary, if only the second electromagnetic actuator 60□ is excited as described above in order to raise the motor swash plate 20, the second check valve 93□ will be forcibly opened, and the motor swash plate 20 will be erected. 20, the piston 85 moves downward, and the oil in the first oil chamber 88 flows through the hydraulic conduit 92 to the second oil chamber 89.
Moving on, the rising operation of the motor swash plate 20 is permitted.

During such a tilting or rising operation of the motor swash plate 20, pulsations are generated in the moment (moment) Mg and Mf acting on the motor swash plate 20 from the motor plungers 19, 19, etc., and the motor swash plate 2
0 is about to vibrate, the second check valve 93□ in the closed state
Alternatively, the oil flow in the hydraulic conduit 92 is regulated in one direction by the first check valve 93°, thereby suppressing vibration of the motor swash plate 20, and stabilizing the rising or tilting operation.

In addition, in order to hold the motor swash plate 20 at an arbitrary angular position,
As mentioned above, if both electromagnetic actuators 6 (li, 602) are demagnetized, both check valves 931, 93□ are closed and the hydraulic conduit 92 is cut off. No oil flow is prevented and movement of the piston 85 is prevented so that the first control lever 82 of the trunnion shaft 80
is fixed. In this way, the motor swash plate 20 is stably held at any angular position, and the motor plunger 19
...It does not vibrate even if it receives a pulsating moment from the group.

In FIG. 13, a reserve tank 100 is installed at the top of the cylinder 84, and a relief boat 101 and a supply boat 102 are bored in the earthen wall of the cylinder 84 to communicate the reserve tank 100 into the cylinder 84.

First and second cup seals 103 and 104 having a one-way sealing function that closely contact the inner peripheral surface of the cylinder 84 are attached to the outer periphery of both ends of the piston 85.
A piston 8 is disposed on the inner periphery of the window 86 on both left and right sides of the window 86.
O-rings 105 and 106 are attached to the outer circumferential surface of the intermediate portion of 5 in close contact with each other.

Thus, in the relief boat 101, the piston 85 is in the first position.
When located at the left limit of movement in Figure 3 (upper limit of movement in Figure 12),
The supply boat 102 opens into the first hydraulic chamber 88 immediately before the first cuff seal 103, and the supply boat 102 is always connected to the second cuff seal 103.
4 and the ○ ring 106 opens to the inner surface of the cylinder 84.

Therefore, when the piston 85 is located at the left movement limit, if pressure increases in the first oil chamber 88 due to an increase in oil temperature or the like, the pressure is released from the relief boat 101 to the reserve tank 100. Furthermore, when the piston 85 moves to the left, the first oil chamber 88 is pressurized by the piston 85 from the moment the first cup seal 103 passes through the opening of the relief boat 101, and the flow from the first oil chamber 88 to the second oil chamber 89 is increased. Allow oil to flow. At that time, if the pressure in the second hydraulic chamber 89 is reduced to a predetermined pressure or less, the oil in the reserve tank 100 is transferred from the supply boat 102 to the cylinder 84 and the piston 85 due to the pressure difference between the reserve tank 100 and the second oil chamber 89. the second cup seal 104 through the sliding gap of the second cup seal 104.
The acid is supplied to the acid chamber 89 while being bent toward the oil chamber 89 side.

Referring again to FIG. 4, the support member 54 that supports the operating ring 52 of the second eccentric wheel 49 via the pivot shaft 53 is connected to the trunnion axis O in the support hole 1) O provided in the crankcase 4.
The actuating ring 5 is slidably fitted in parallel with f.
2 to follow the sliding movement of the support member 54, the actuating ring 52
The connecting hole 55 and the inner lever 56a of the bell crank 56 are slidable in the direction of the trunnion axis 0□.

The support member 54 is provided with a cam hole 1) 1 and a second control lever 83 fixed to the lower trunnion shaft 80'.
is inserted into this cam hole 1)1.

The inner surface of the cam hole 1) 1 on the side of the support hole 1) 0 is a slope 1) 1a that engages with the second control lever 83. It is now under pressure. According to the push-up, the support member 54 slides through the support hole 1) 0 and displaces the second eccentric wheel 49 in the direction of the concentric position 1h via the operating ring 52, thereby moving the motor swash plate 20. In the upright position, the second eccentric 49 reaches a concentric position.

When the second eccentric wheel 49 reaches the concentric position, all the second distribution valves 46, 46... are closed as shown in Fig. 8, cutting off communication between the hydraulic pump and motors P and M. do. As a result, the pump plungers 9, 9, . . . and the motor plungers 19, 19, . transmission efficiency can be increased.

The support member 54 is attached to the second eccentric wheel 49 in the support hole 1)0.
A return spring 1) 2 is contracted and springs in the direction of the first eccentric position e. Therefore, in the inclined state of the motor swash plate 20, the second eccentric shaft 49 is held at the first eccentric position e by the elastic force of the return spring l12, and the distribution valves 46, 46, . . . are given normal reciprocating motion. I can do it.

Again, in FIGS. 1 and 2, the output shaft 25 has an oil passage 63 with a dead end in the center thereof, and the open end of the oil passage 63 is connected to the side wall of the crankcase 4. A fuel supply pipe 64 supported by the fuel pipe 64 is inserted. This oil supply pipe 64 is
It communicates with the inside of the oil pan 69 at the bottom of the crankcase 4 through an oil passage 65 formed in the side wall of the crankcase 4, a filter 66 attached to the side wall, a replenishment pump 67, and a strainer 68. It is driven from the input member 5 via gears 70, 71. Therefore, oil in the oil pan 69 is constantly supplied to the oil passage 63 by the replenishment pump 67 while the input member 5 is rotating.

The oil passage 63 communicates with the inner oil chamber 40 via a radial replenishment hole 72 formed in the output shaft 25. Further, a check valve 73 is installed in the core oil passage 63 to prevent oil from flowing back into the oil supply pipe 64 .

Therefore, if hydraulic oil leaks from the hydraulic closed circuit between the hydraulic pump P and the hydraulic motor M during normal load operation, the hydraulic oil is replenished from the oil passage 63 to the inner oil chamber 40 through the replenishment hole 72.

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, so that the outer oil chamber 41 is at low pressure and the inner oil chamber 4 is at low pressure.
0 changes to high pressure, and the hydraulic oil attempts to flow back from the inner oil chamber 40 to the oil passage 63, but the back flow is blocked by the check valve 73.

Therefore, the reverse load can be reliably transmitted from the hydraulic motor M to the hydraulic pump P, and a good engine braking effect can be obtained.

In addition, 74.75 in FIG. 1 indicates the connection from the oil passage 63 to the plunger 9,
This is an orifice hole drilled in the output shaft 25 in order to supply lubricating oil to each contact portion between the output shaft 19 and the swash plate 10, 20.

C9 Effects of the Invention As described above, according to the first feature of the present invention, the thrust load distribution applied to the motor swash plate of the motor plunger group during the expansion stroke is equalized on both sides of the trunnion axis of the motor swash plate. A second state in which the same distribution is biased more toward one side of the trunnion axis to provide a moment in the upright direction to the motor swash plate, and a second state in which the same distribution is biased more toward the other side of the trunnion axis to provide a moment in the motor swash plate. The present invention is equipped with a speed change control device that controls the distribution mechanism so as to select the third state that applies a moment in the tilting direction to the plate, thereby controlling the thrust load distribution exerted on the motor swash plate of the motor plunger group during the expansion stroke. As a result, the angle of the motor swash plate can be freely adjusted to obtain a desired gear ratio, and the structure is extremely simple and inexpensive compared to those using conventional hydraulic servo motors.

According to a second feature of the present invention, in addition to the first feature, an actuating lever that is linked to the tilting of the motor swash plate is connected to a piston that slides into a fixed cylinder, and a space is defined between the cylinder and the piston. The first and second oil chambers, which are formed and face each other with the piston in between, are communicated with each other via a hydraulic conduit filled with oil, and the hydraulic conduit is filled with acid in conjunction with the first state. Since a valve device is installed to shut off the hydraulic conduit, the motor swash plate can be hydraulically fixed by shutting off the hydraulic conduit using the valve device. The plate can be reliably held at any angular position.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional plan view of a hydrostatic continuously variable transmission installed in the power transmission system of a motorcycle, and FIG. 2 is a longitudinal sectional rear view of the same transmission. , Figure 3 is the second
The ■-■ line sectional view in the figure, Figures 4 and 5 are IV of Figure 2.
- IV line and VV line sectional views, Figures 6 to 8 are explanatory diagrams of the operation of Figure 5, and Figures 5A to 7A are the motor plunger group in the states of Figures 5 to 7. Thrust load distribution diagram, Figure 9 is a perspective view of the first distribution valve, Figure 10 is a perspective view of the second distribution valve, Figure 1) is a sectional view taken along the line XI-XI in Figure 4, and Figure 12 is a gear shift diagram. A vertical sectional view of the control device, FIG. 13 is a sectional view taken along the line xm-xm in FIG. 12. C...speed change control device, P...hydraulic pump, S...
Swash plate stabilizer, T...Continuously variable transmission, M...Hydraulic motor, Mf...Rising moment, 'Mg...Tilt moment, 0□...Motor swash plate trunnion axis, ■...
... Crankshaft, 5... Input member, 9... Pump plunger, lO... Pump swash plate, 18... Cylinder hole, 19... Motor plunger, 20... Motor swash plate, 25 ...Output shaft, 46.49...Second distribution valve and second eccentric valve forming the distribution mechanism, 92...Hydraulic conduit, 93,...First check valve forming the valve device, 932・
...Second check valve constituting the valve device Patent application Person Honda Motor Co., Ltd. Figure 3 Figure a Figure 7 Figure 6

Claims (2)

[Claims] (1) A hydraulic closed circuit is formed between the swash plate type hydraulic pump and the swash plate type hydraulic motor, and this hydraulic closed circuit accommodates the high pressure oil passage of the circuit and the motor plunger in the expansion stroke of the hydraulic motor. In a hydrostatic continuously variable transmission provided with a distribution mechanism that communicates with a cylinder hole and communicates a low-pressure oil passage of the circuit with a cylinder hole that accommodates a motor plunger that is on a contraction stroke of a hydraulic motor, A first state in which the thrust load distribution exerted on the motor swash plate of the plunger group is equalized on both sides of the trunnion axis of the motor swash plate; The distribution mechanism is controlled so as to be able to select a second state in which a moment is applied and a third state in which the same distribution is biased more toward the other side of the trunnion axis and a moment in a tilting direction is applied to the motor swash plate. A hydrostatic continuously variable transmission characterized by being equipped with a speed change control device. (2) A hydraulic closed circuit is formed between the swash plate type hydraulic pump and the swash plate type hydraulic motor, and this hydraulic closed circuit accommodates the high pressure oil passage of the circuit and the motor plunger in the expansion stroke of the hydraulic motor. In a hydrostatic continuously variable transmission provided with a distribution mechanism that communicates with a cylinder hole and communicates a low-pressure oil passage of the circuit with a cylinder hole that accommodates a motor plunger that is on a contraction stroke of a hydraulic motor, A first state in which the thrust load distribution exerted on the motor swash plate of the plunger group is equalized on both sides of the trunnion axis of the motor swash plate; The distribution mechanism is controlled so as to be able to select a second state in which a moment is applied and a third state in which the same distribution is biased more toward the other side of the trunnion axis and a moment in a tilting direction is applied to the motor swash plate. A control lever that is equipped with a speed change control device and that is linked to the tilting of the motor swash plate is connected to a piston that slides into a fixed cylinder, and a first The second oil chambers are communicated with each other via a hydraulic conduit filled with oil, and the hydraulic conduit is equipped with a valve device that shuts off the conduit in conjunction with the first state. Hydrostatic continuously variable transmission.