JPH0689828B2 - Hydrostatic continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a static hydraulic system in which a hydraulic closed circuit is formed between a swash plate hydraulic pump and a variable displacement swash plate hydraulic motor. The present invention relates to improvement of a continuously variable transmission.

(2) Conventional technology Such a hydrostatic continuously variable transmission is disclosed in, for example, Japanese Patent Publication No. 59-38467.
It is already known as described in the publication.

(3) Problems to be Solved by the Invention In the conventional hydrostatic continuously variable transmission, the pump cylinder of the hydraulic pump is rotatably slidably pressed against the distribution board fixed to the motor cylinder of the hydraulic motor. The hydraulic oil of the hydraulic pump and the hydraulic motor is transmitted and received through an oil passage penetrating the rotary sliding surface. For this reason, the pressure oil easily leaks from between the rotary sliding surfaces of the distributor and the pump cylinder which face each other, and the leakage causes a reduction in the transmission efficiency.

Therefore, the present invention enhances the transmission efficiency by reliably transmitting and receiving hydraulic oil between the hydraulic pump and the hydraulic motor,
Another object of the present invention is to provide a simple and effective hydrostatic continuously variable transmission which can suppress relative rotation of the hydraulic pump and the hydraulic motor to further improve the transmission efficiency when the gear ratio is 1.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention integrally connects a pump cylinder of a hydraulic pump and a motor cylinder of a hydraulic motor to an output shaft, Between the pump cylinder and the motor cylinder, an annular high pressure oil passage connected to the discharge stroke side cylinder hole of the hydraulic pump and an annular low pressure oil passage connected to the suction stroke side cylinder hole of the hydraulic pump are concentrically formed, and the radius is A large number of distribution valves that can reciprocate between the outer position and the inner position in the direction to alternately communicate the many cylinder holes of the motor cylinder with the high pressure oil passage and the low pressure oil passage are arranged radially.
In the inclined state of the motor swash plate of the hydraulic motor, the distribution valve is reciprocated in accordance with the rotation of the pump cylinder to cause the expansion stroke side cylinder hole of the hydraulic motor to be the high pressure oil passage and the contraction stroke side cylinder hole of the hydraulic motor to be the low pressure oil. An eccentric wheel for communicating with each of the passages is engaged with the distribution valve, and when the motor swash plate is in an upright state, the reciprocating movement of the distribution valve is stopped to disconnect between the hydraulic motor and the low and high pressure oil passages. The eccentric wheel is linked to the motor swash plate. The interlocking between the eccentric wheel and the motor swash plate includes mechanical interlocking, electrical interlocking, hydraulic interlocking and the like.

(2) Operation When the continuously variable transmission is operated with the motor swash plate inclined, the high-pressure hydraulic fluid discharged from the hydraulic pump to the high-pressure oil passage is transferred to the hydraulic motor via the distribution valve controlled by the eccentric wheel. Of the low pressure hydraulic fluid discharged from the contraction side cylinder hole of the hydraulic motor is also sent to the low pressure oil passage through the distribution valve controlled by the eccentric wheel, and then the hydraulic pump. Inhaled into. In this way, the transfer of hydraulic oil is repeated between the hydraulic pump and the hydraulic motor, whereby power is transmitted from the hydraulic pump to the hydraulic motor at an arbitrary gear ratio.

If the motor swash plate is placed upright to control the gear ratio to 1, the eccentric wheel controls all the distribution valves to the closed position in conjunction with it, so both the high pressure oil passage and the low pressure oil passage are connected to the hydraulic motor. Is cut off from communication.

By the way, when the motor swash plate is in the upright state, theoretically the capacity of the hydraulic motor becomes zero, so that the hydraulic oil is not transferred between the hydraulic pump and the hydraulic motor, and the hydraulic pump is in the hydraulic lock state. The input member of the hydraulic pump and the output shaft of the hydraulic motor are mechanically and integrally connected. However, in reality, some bubbles are present in the hydraulic fluid in the hydraulic closed circuit between the hydraulic pump and the hydraulic motor, and the hydraulic fluid is slightly compressible, so that there is a slight compressibility between the input member and the output shaft. Causes a slight relative rotation, which contributes to a reduction in transmission efficiency.

However, in the present invention, since the high-pressure oil passage and the low-pressure oil passage are disconnected from the hydraulic motor as described above, the hydraulic circuit volume communicating with the hydraulic pump is reduced by the volume of the hydraulic motor, so that the hydraulic pump compresses the hydraulic oil. Greatly reduced the amount,
The relative rotation between the input member and the output shaft is reduced, and the transmission efficiency is improved.

(3) Embodiment One embodiment of the present invention will be described below with reference to the drawings.
First, in FIG. 1 and FIG. 2, the power of the engine E of the motorcycle is the crankshaft 1 from the chain type primary speed reducer 2, the hydrostatic continuously variable transmission T, and the chain type secondary speed reducer 3 in order. After that, it is transmitted to a rear wheel (not shown).

The continuously variable transmission T is composed of a constant displacement type swash plate hydraulic pump P and a variable displacement type swash plate hydraulic motor M, and a crankcase 4 supporting the crankshaft 1 is used as a casing.
Accommodated in it.

The hydraulic pump P is an output sprocket 2a of the primary speed reducer 2.
A cup-shaped input member 5 integrally provided with a pump cylinder 7, a pump cylinder 7 that is rotatably fitted to an inner peripheral wall of the input member 5 via a needle bearing 6, and a center of rotation of the pump cylinder 7 is surrounded by the pump cylinder 7. , Which are slidably fitted in a plurality of odd-numbered cylinder holes 8, 8 ... of an annular array, respectively, and these pump plungers 9, 9
And a pump swash plate 10 that abuts the outer end of.

The pump swash plate 10 has a thrust roller bearing 11 on the inner end wall of the input member 5 in a posture inclined at a constant angle with respect to the axis of the pump cylinder 7 about a virtual trunnion axis O ₁ orthogonal to the axis of the pump cylinder 7. Is rotatably supported on the back side, and when the input member 5 rotates, the pump plungers 9,9
A reciprocating motion can be given to ... to repeat the suction and discharge strokes.

In order to improve the followability of the pump plunger 9 with respect to the pump swash plate 10, a spring for urging the pump plunger 9 in the extension direction may be contracted in the cylinder hole 8.

The rear surface of the input member 5 is a thrust roller bearing 12
Is supported by the support cylinder 13 via.

On the other hand, the hydraulic motor M includes a motor cylinder 17 coaxially arranged to the left of the pump cylinder 7, and a plurality of odd-numbered cylinder holes arranged in an annular array in the motor cylinder 17 so as to surround the rotation center. The motor plungers 19, 19 that are slidably fitted to the 18, 18 ..., the motor swash plate 20 that contacts the outer ends of the motor plungers 19, 19 ..., and the back surface of the motor swash plate 20 through the thrust roller bearing 21. And a cup-shaped swash plate anchor 23 that supports the swash plate holder 22.

The motor swash plate 20 can tilt between an upright position that is perpendicular to the axis of the motor cylinder 17 and a tilted position that tilts at a certain angle. At that tilted position, the motor cylinder 17 rotates. Accordingly, the motor plungers 19, 19 ... Can be reciprocally moved to repeat the expansion and contraction strokes.

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 contracted in the cylinder hole 18.

The pump cylinder 7 and the motor cylinder 17 form an integral cylinder block B, and the output shaft 25 is passed through the center of the cylinder block B. The motor cylinder 17 is attached to the flange 25a formed integrally with the outer periphery of the output shaft 25.
The outer end of the cylinder is struck, the pump cylinder 7 is spline-fitted to the output shaft 25, and the circlip 26 that abuts the outer end of the pump cylinder 7 is locked to the output shaft 25. Stuck to.

The output shaft 25 also penetrates the input member 5 and rotatably supports the member 5 via a needle bearing 27.

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

Further, the output shaft 25 penetrates through the central portions of the motor swash plate 20, the swash plate holder 22, and the swash plate anchor 23, and supports the back surface of the swash plate anchor 23 at its left end via a thrust roller bearing 32. The support cylinder 33 is spline-fitted and fixed with the nut 34 together with the input sprocket 3a of the secondary speed reducer 3. The left end of the output shaft 25 is freely rotatable with the crankcase 4 through the support cylinder 33 and the roller bearing 35. Supported by.

A hemispherical centering body 36 that slidably engages with the inner peripheral surface of the pump swash plate 10 in all directions is slidably fitted to the output shaft 25. The aligning body 36 includes a plurality of disc springs 38.
Force presses the pump swash plate 10 against the thrust roller bearing 11, whereby the pump swash plate 10 is always aligned.

Further, a hemispherical centering body 37 that slidably engages with the inner peripheral surface of the motor swash plate 20 in all directions is slidably fitted to the output shaft 25. The aligning body 37 moves the motor swash plate 20 to the thrust roller bearing 21 by the force of a plurality of disc springs 39.
The swash plate 20 is constantly pressed against the swash plate 20.

The swash plates 10 and 20 are strengthened in alignment, and the pump swash plate 10
And the pump plungers 9,9 ... Group, the motor swash plate 20 and the motor plungers 19,19 .. Spherical recesses 10a, 20a for engaging the spherical end portions 9a, 19a of the respective are formed. At that time, the spherical concave portions 10a, 20a are swash plates 10, 20
The radius of curvature of the spherical end portions is ensured to ensure proper engagement with the spherical end portions 9a, 19a at any rotational position of.
It is set larger than that of 9a and 19a.

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

In the cylinder block B, annular inner oil passages are arranged concentrically around the output shaft 25 between the cylinder holes 8, 8 ... Group of the pump cylinder 7 and the cylinder holes 18, 18 ... Group of the motor cylinder 17. 40 and the outer oil passage 41, the annular partition between both oil passages 40, 41 and the outer wall of the outer oil passage 41 radially penetrate through, and the same number of cylinder holes 8, 8 ... And 18, 18 ... Holes 42,4
2 and the second valve holes 43, 43, and the adjacent cylinder holes 8, 8 ... and the first valve holes 42, 42. Holes 18, 18 ... and second valve hole 4
There are provided a large number of motor ports b, b ... Which communicate the 3, 43 ... At that time, the inner oil passage 40 is formed between the opposing circumferential surfaces of the cylinder block B and the output shaft 25, and the outer oil passage 41 is fitted to the cylinder block B and welded to the outer circumference thereof. It is formed between the peripheral surfaces facing the sleeve 44. Here, the inner and outer oil passages 40, 41 correspond to the low pressure and high pressure oil passages of the present invention.

The first valve holes 42, 42 ... And the first distribution valves 45, 45 ... And the second valve holes 43, 43.

Each of the first distribution valves 45 is formed in a spool type as shown in FIG. 9, and when it occupies a position radially outward of the first valve hole 42, the corresponding pump port a communicates with the outer oil passage 41. And the corresponding oil passage 40 and the corresponding cylinder hole 8
When communicating with only the outer oil passage 41 and occupying the radially inner position of the first valve hole 42, the corresponding pump port a is communicated with the inner oil passage 40 and is not communicated with the outer oil passage 41. The cylinder hole 8 is connected only to the inner oil passage 40.

In order to give such an operation to each first distribution valve 45, the first
An eccentric wheel 47 surrounds the first distribution valves 45, 45 ... Engages with their outer ends, and a follower wheel 47 'concentric with the eccentric wheel 47.
Are disposed inside the first group of distribution valves 45, 45 ... And are engaged with the engagement grooves 45a, 45a ... Of their inner ends (see FIG. 3). The follower wheel 47 'is made of steel wire and has the first distribution valve 4
Are arranged so as to spring in the direction of engagement with the first eccentric wheel 47. It should be noted that the follower wheel 47 'may be provided with one cut in order to absorb a manufacturing error in its diameter.

The first eccentric ring 47 is rotatably supported by the input member 5 via a ball bearing 48, and as shown in FIG.
The pump swash plate 10 is arranged at a position eccentric from the center of the output shaft 25 along the virtual trunnion axis O ₁ by a constant distance ε ₁ . Therefore, when a relative rotation occurs between the input member 5 and the pump cylinder 7, each first distribution valve 45 has a stroke in the valve hole 42 that is a distance twice the eccentric amount ε ₁ of the first eccentric ring 47. Reciprocates between the outer position and the inner position.

Each of the second distribution valves 46 is formed in a spool type,
When occupying the radially outer position of the second valve hole 43, the corresponding motor port b communicates with the outer oil passage 41 and the inner oil passage 40.
When the corresponding cylinder hole 18 is communicated with the outer oil passage 41 only and the radially inner position of the second valve hole 43 is occupied, the corresponding motor port b is communicated with the inner oil passage 40. When the corresponding cylinder hole 18 is made to communicate only with the inner oil passage 40 and the central position between the above two positions is occupied by making the outer oil passage 41 incommunicable, the corresponding motor port 6 is connected to the inner and outer oil passages 40, 41. To be cut off.

The second distribution valve 46, as shown in FIGS. 5 and 10,
The valve 46 has a notch 46b that is notched on one side of the outer peripheral surface and a lateral hole 46c that constantly communicates with the motor port b in the notch 46b.
In order to connect and disconnect the motor port b with the inner and outer oil passages 40 and 41 by means of the above-mentioned notch 46a,
Or hidden in the partition wall between the oil passages 40 and 41.

In order to give such an operation to each second distribution valve 46, the second
An eccentric wheel 49 surrounds the second distribution valves 46, 46 ... Engages with their outer ends, and has a follower wheel 49 'concentric with the eccentric wheel 49.
Are disposed inside the second distribution valves 46, 46 ... Group and are engaged with the engagement grooves 46a, 46a ... Of their inner ends, and the engagement prevents rotation of each second distribution valve 46. (See FIG. 5). The follower wheel 49 'is made of steel wire and has a second distribution valve 46,4.
6 are arranged so as to repel in the engagement direction with the second eccentric wheel 49. Incidentally, the follower wheel 49 'may also be provided with one cut, like the follower wheel 47'.

As shown in FIG. 4, the second eccentric wheel 49 has a first eccentric position e which is eccentric from the center of the output shaft 25 along the tilt axis of the motor swash plate 20, that is, the trunnion axis O ₂ by a constant distance ε ₂ , A second eccentric position f slightly offset from the first position e to one side of the trunnion axis O ₂ , and a second eccentric position slightly offset from the first eccentric position e to the cut side of the trunnion axis O ₂ . Three
The eccentric position g and the concentric position h concentric with the output shaft 25 are controlled.

Thus, when the second eccentric wheel 49 occupies the first eccentric position e to the third eccentric position g, when the motor cylinder 17 rotates,
Each second distribution valve 46 reciprocates between the outer position and the inner position with a stroke that is twice the eccentric amount ε ₂ of the second eccentric wheel 49 within the valve hole 43, and also the concentric position h Occupies all the second distribution valves 49, 4 due to the rotation of the motor cylinder 17.
9 ... stays in the central position.

As shown in FIG. 2, a pair of upper and lower trunnion shafts 80, 80 ′ aligned on the trunnion axis O ₂ of the motor swash plate 20 are integrally projectingly provided at both ends of the swash plate holder 22. , 80 'are rotatably supported by the swash plate anchor 23 via a needle bearing 81 and a roller bearing 81', respectively. In other words, these trunnion shafts 80,8
The trunnion axis O ₂ is defined by 0 '.

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

In the above configuration, when the input member 5 of the hydraulic pump P is rotated from the primary reduction gear 2 when the second eccentric wheel 49 occupies the first eccentric position e, the pump swash plate 10 causes the pump plungers 9, 9 ,. Suction and discharge strokes are given alternately, and the first distribution valve 45 adjacent to the pump plunger 9 entering the suction stroke is operated to the inward position by the cooperation of the first eccentric wheel 47 and the follower wheel 47 ', and the discharge stroke is The first distribution valve 45 adjacent to the incoming pump plunger 9 is actuated to the outward position by the cooperation of the first eccentric wheel 47 and the follower wheel 47 '. Therefore, each pump plunger 9 sucks the working oil from the inner oil passage 40 into the cylinder hole 8 in the suction stroke, and pumps the working oil from the cylinder hole 8 to the outer oil passage 41 in the discharge stroke.

The high-pressure hydraulic oil sent to the outer oil passage 41 enters the second eccentric ring in the cylinder hole 18 that houses the motor plunger 19 in the expansion stroke.
While being fed through the second distribution valve 46 which is controlled to the outer position by the 49 and the follower wheel 49 ', the hydraulic oil in the cylinder hole 18 accommodating the motor plunger 19 in the contraction stroke is the second eccentric wheel. It is discharged to the inner oil passage 40 through the second distribution valve 46 which is controlled to the inner position by 49 and the follower wheel 49 '.

During this time, the reaction torque that the pump cylinder 7 receives from the pump swash plate 10 via the pump plunger 9 in the discharge stroke,
The cylinder block B is rotated by the sum of the reaction torque that the motor cylinder 17 receives from the motor swash plate 20 via the motor plunger 19 in the expansion stroke, and the rotation torque is transmitted from the output shaft 25 to the secondary reduction gear 3. It

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

Therefore, if the capacity of the hydraulic motor M is changed from zero to a certain value, the gear ratio can be changed from 1 to a certain required value.

By the way, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 19, the gear ratio is continuously controlled from 1 to a certain value by tilting the motor swash plate 20 from the upright position to a certain tilt position. be able to.

During such operation of the hydraulic pump P and the hydraulic motor M, the pump swash plate 10 receives thrust loads from the pump plungers 9, 9 ... Group, and the motor swash plate 20 receives thrust loads in the opposite directions from the motor plungers 19, 19 ... Group. However, the thrust load received by the pump swash plate 10 is supported by the output shaft 25 via the thrust roller bearing 11, the input member 5, the thrust roller bearing 12, the support cylinder 13 and the nut 30, and the thrust load received by the motor swash plate 20. Is thrust roller bearing 21, swash plate holder 22, swash plate anchor 23, thrust roller bearing
It is also supported by the output shaft 25 via the support tube 33, the support tube 33, the sprocket 3a and the nut 34. Therefore, the thrust load causes only a tensile stress on the output shaft 25, and
It has no effect on the crankcase 4 supporting the 25.

By the way, when the second eccentric wheel 49 occupies the first eccentric position e, as shown in FIG. 5, among the many second distribution valves 46, 46, the high pressure outer oil passage 41 communicates with the motor port b. Since the same number exists on both sides of the trunnion axis O ₂ on average, the thrust load distribution exerted on the motor swash plate 20 of the motor plungers 19, 19 ... Group of the expansion stroke is as shown by Ae in FIG. 5A. Equally equal on both sides of the trunnion axis O ₂ (ie α = β). Therefore, although such a thrust load distribution does not cause a tilting moment about the trunnion axis O ₂ in the motor swash plate 20, the second eccentric wheel 46 causes the second eccentric ring f to move.
As shown in FIG. 6, a large number of second distribution valves 46, 46 ...
Of these, the number of those that connect the high-pressure outer oil passage 41 to the motor port is greater on the left side than on the right side of the trunnion axis O ₂ , so the motor plungers of the expansion stroke motor groups 19, 19 ... The distribution of the thrust load exerted on the plate 20 is wider on the left side than on the right side of the trunnion axis O ₂ as shown by Af in FIG. 6A (ie α> β). Therefore,
A standing moment Mf (see FIG. 1) about the trunnion axis O ₂ acts on the motor swash plate 20, and the moment Mf causes the motor swash plate 20 to rotate in the standing direction.

On the contrary, when the second eccentric wheel 49 occupies the third eccentric position g, as shown in FIG. 7, a large number of second distribution valves 46, 46 ...
Of these, the number of those that communicate the high-pressure outer oil passage 41 with the motor port b is greater on the right side than on the left side of the trunnion axis O ₂ , so the motors of the motor plungers 19, 19 ... The distribution of the thrust load exerted on the swash plate 20 is wider on the right side than on the left side of the trunnion axis O ₂ (that is, α> β), as indicated by Ag in FIG. 7A. Therefore, the tilting moment Mg (see FIG. 1) about the trunnion axis O ₂ 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 ring 49 is moved to the first to third eccentric positions e ...
In order to control to g, the following shift control device C is connected to the second eccentric wheel 49.

That is, in FIG. 2 and FIG. 5, the second eccentric ring 49 is rotatably supported by the operating ring 52 via the ball bearing 50, and the operating ring 52 connects the second eccentric ring 49 to the second eccentric ring. The lower part is supported by a support member 54 via a pivot 53 arranged orthogonal to the trunnion axis O ₂ so as to be able to swing from the position f to the third eccentric position g.

A connecting hole 55 is provided in an upper portion of the operating ring 52, and a second eccentric ring 49 is provided in the connecting hole 55 at a first eccentric position f to a third eccentric position.
A bell crank 56 for swinging to the eccentric position g is engaged. As shown in FIG. 2, the bell crank 56 has a rotating shaft 56 that is supported by the crank case 4 via bearings 51.
c, the inner lever 56a fixed to the rotating shaft 56c inside the crankcase 4, and the rotating shaft 56c outside the crankcase 4.
The outer lever 56b is fixed to the inner lever 56a.
The tip of is inserted into the connecting hole 55.

At the tip of the outer lever 56b, as shown in FIG.
Actuating rods 58 ₁ and 58 _{2 of} a pair of first and second electromagnetic actuators 57 ₁ and 57 ₂ facing each other are connected so as to sandwich the lever 56b. Solenoid _{60 1} first and second electromagnetic actuator 57, 57 _2, surrounds the said operation rod 58 _1, 58 ₂ movable iron core 59 ₁ which is fixed to, 59 _2, the movable iron core 59 _1, 59 _{2 1} and 60 ₂ and this solenoid 60 ₁ and 60 ₂
And a return spring 62 ₁ and 62 ₂ for urging the movable iron cores 59 ₁ and 59 ₂ toward the outer lever 56b, that is, toward the inactive position, respectively. The container body 61 is fixed to a proper position of the crankcase 4.

Thus, when the solenoids 60 ₁ and 60 ₂ of both electromagnetic actuators 57 ₁ and 57 ₂ are both demagnetized, both operating rods 58 ₁ and 58 ₂ are
The bell crank 56 can be held in the neutral position by the cooperation of 2 ₁ and 62 ₂ , so that the second eccentric wheel 49 can be controlled to the first eccentric position e via the operating ring 52. Also the first electromagnetic actuator
If the excitation only 57 ₁ of the solenoid 60 _{and second} solenoid 60 _first or second electromagnetic actuator 57 _2, corresponding actuating rod 58 ₁ or 58
_The bell crank is driven by the forward movement of the _second outer lever 56b.
The 56 is swung counterclockwise or clockwise in the above-mentioned neutral position in FIG. 5, whereby the second eccentric wheel 49 is moved through the operating ring 52.
Can be controlled to the third eccentric position g or the second eccentric position f. In this case, the demagnetized second electromagnetic actuator 57 ₂
Or further summer as retraction is applied from a normal inoperative position with the the swing of the first electromagnetic actuator 57 _1, the bell crank 56.

The positioning notch 96 formed on the lower surface of the outer lever 56b is provided with
The ball 97 housed in the housing hole 99 of the actuator body 61 and biased to project by the spring 98 is elastically engaged.

On the other hand, a swash plate stabilizer S is connected to the upper trunnion shaft 80. The swash plate stabilizing device S includes a cylinder 84 fixed to a proper position of the crankcase 4 and a piston 85 slidably fitted on the cylinder 84. Window 86 on the side wall of cylinder 84
However, a connecting hole 87 that penetrates the piston 85 in the lateral direction and faces the window 86 is formed in the center of the piston 85, and the first control lever 82 fixed to the trunnion shaft 80 is connected through the window 86. The piston 85 is engaged with the hole 87 and slides in response to the rotation of the trunnion shaft 80.

Thus, in FIG. 12, the maximum tilt position and the upright position of the motor swash plate 20 are determined by the upper and lower motion limits of the piston 85, and between the piston 85 and the lower end wall of the cylinder 84. First
An oil chamber 88 is defined, and a second oil chamber 89 is defined between the piston 85 and the upper end wall of the cylinder 84. The first oil chamber 88 is returned to urge the piston 85 toward the second oil chamber 89. The spring 90 is retracted.

The first and second oil chambers 88, 89 are communicated with each other via a hydraulic conduit 92 filled with oil, and the first and second check valves 93 ₁ , 93 ₂ are provided in the middle of the hydraulic conduit 92. It is inserted in series.

The first check valve 93 _1, to allow the hydraulic conduit 92 from the first oil chamber 88 of the oil flow in the direction of the second oil chamber 89 is adapted to prevent the reverse flow, the second check the valve 93 ₂ is adapted to permit the flow of oil from the second oil chamber 89 in the direction of the first oil chamber 88 on the opposite, arresting its reflux with it. Moreover,
The first check valve 93 ₁ is forcibly opened by the further backward movement of the operating rod 61 ₂ of the second electromagnetic actuator 60 ₂ from the normal non-operating position, and the second check valve 931 is also provided. 93 ₂ is the first electromagnetic actuator 6
0 ₁ As is forcibly opened by further retraction from the normal inoperative position of the actuating rod 61 _1, are respectively disposed at both ends of the actuator body 64.

Therefore, in order to tilt the motor swash plate 20, if only the first electromagnetic actuator 60 ₁ is excited as described above, its operating rod 5
The retraction of the other operating rod 58 ₂ caused by the forward operation of 8 ₁ from the first check valve 93 ₁ is forced open, moves upward piston 85 with the tilting operation of the motor swash plate 20, the 2 The oil in the oil chamber 89 moves 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 allowed. In contrast, in order to raise the motor swash plate 20, if the second excitation only electromagnetic actuator 60 _2, as described above, this time with the standing operation of from the second check valve 93 ₂ is forced open, the motor swash plate 20 piston
When 85 moves downward, the oil in the first oil chamber 88 passes through the hydraulic conduit 92 to the second oil chamber.
Moving to the oil chamber 89, the standing motion of the motor swash plate 20 is allowed.

During such tilting or standing up of the motor swash plate 20, if the motor swash plate 20 tries to vibrate due to pulsation of the moments Mg, Mf acting on the motor swash plate 20 from the motor plungers 19, 19 ,. The second check valve 93 ₂ or the first check valve 93 ₁ restricts the flow of oil in the hydraulic conduit 92 in one direction, so that the vibration of the motor swash plate 20 is suppressed, and its standing motion or tilting motion is suppressed. Can be stabilized.

If both electromagnetic actuators 60 ₁ and 60 ₂ are demagnetized as described above in order to hold the motor swash plate 20 at an arbitrary angular position, both check valves 93 ₁ and 93 ₂ are closed. Becomes the hydraulic conduit 92
Is blocked, the flow of oil in the hydraulic conduit 92 is completely blocked, the movement of the piston 85 is blocked, and as a result, the first control lever 82 of the trunnion shaft 80 is fixed. In this way, the motor swash plate 20 is stably held at an arbitrary angular position, and does not vibrate even when it receives a pulsating moment from the group of motor plungers 19, 19.

In FIG. 13, a reserve tank 100 is installed above the cylinder 84, and the reserve tank 100 is installed in the cylinder 84.
Relief port 101 and supply port 102 communicating with inside
Are drilled in the upper wall of the cylinder 84.

First and second cup seals 103 and 104 having a one-way sealing function that are in close contact with the inner peripheral surface of the cylinder 84 are mounted on the outer periphery of both ends of the piston 85, and on the inner periphery of the cylinder 84,
On both left and right sides of the window 86, O-rings 105 and 106 which are in close contact with the outer peripheral surface of the intermediate portion of the piston 85 are mounted.

Thus, the relief port 101 opens into the first hydraulic chamber 88 immediately before the first cup seal 103 when the piston 85 is located at the left limit (upper limit in FIG. 12) in FIG. The supply port 102 is always open on the inner surface of the cylinder 84 between the second cup seal 104 and the O-ring 106.

Therefore, when the piston 85 is located in the left limit,
If a pressure rise occurs in the first oil chamber 88 due to a rise in oil temperature,
The pressure is released from the relief port 101 to the reserve tank 100. Further, when the piston 85 moves to the right, the first oil chamber 88 is pressurized by the piston 85 from the time when the first cup seal 103 passes through the opening of the relief port 101, and the first oil chamber 88 is pressurized.
Allows the flow of oil from 88 to the second oil chamber 89. that time,
When the second hydraulic chamber 89 is depressurized to a predetermined pressure or less, the oil in the reserve tank 100 slides from the supply port 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. Pass through the gap and the second cup seal 104
Is deflected to the second oil chamber 89 side and is supplied to the chamber 89.

Referring again to FIG. 4, the working ring 52 of the second eccentric ring 49 is connected to the pivot 53
The support member 54 supported through the crankcase 4
Is slidably fitted in the support hole 110 provided in the parallel to the trunnion axis O _2, and the operating ring 52 is attached to the support member 54.
In order to follow the sliding of the trunnion axis O of the operating ring 52 and the inner lever 56a of the bell crank 56,
_It can slide in ₂ directions.

The support member 54 is provided with a cam hole 111, and the second control lever 83 fixed to the lower trunnion shaft 80 'is inserted into the cam hole 111. The inner surface of the cam hole 111 on the side of the support hole 110 is an inclined surface 111a that engages with the second control lever 83, and the second control lever is interlocked with the standing motion of the motor swash plate 20.
It is designed to be pressed by 83. According to that press,
The support member 54 slides through the support hole 110 and displaces the second eccentric wheel 49 to the method of the concentric position h via the actuation ring 52, so that the second eccentric wheel 49 is moved upright when the motor swash plate 20 is upright. Reach concentric position h.

When the second eccentric wheel 49 reaches the concentric position h, all the second distribution valves 46, 46 ... Are closed as shown in FIG. 8, and both the high pressure oil passage 41 and the low pressure oil passage 40 are hydraulic motors. It is cut off from M. As a result, the volume of the low-pressure circuit communicating with the hydraulic pump P is reduced by the volume of the hydraulic motor M, so that even if the operating oil contains some air bubbles, the amount of compression of the operating oil by the hydraulic pump P is extremely small and the input The relative rotation between the member 5 and the output shaft 25 can be suppressed to a minimum, that is, the transmission efficiency in the state of the gear ratio 1 can be improved.

In this case, in the illustrated example, the displacement of the second eccentric wheel 49 to the concentric position h is performed steplessly by the action of the inclined surface 111a of the cam hole 111 in conjunction with the standing motion of the motor swash plate 20, Two
The distribution valves 46, 46 ... also endlessly close and reach a closed state. Therefore, the improvement of the transmission efficiency starts slowly before reaching the closed state, so that the shift shock can be prevented from being generated in the closed valve. However, when the shift shock is acceptable, the second distribution valves 46, 46 ... May be closed rapidly when the motor swash plate 20 is upright.

In the support hole 110, the support member 54 is provided on the first eccentric ring 49.
The return spring 112 that elastically springs in the direction of the eccentric position e is contracted.
Therefore, when the motor swash plate 20 is tilted, the second eccentric wheel 49
Is held at the first eccentric position e by the elastic force of the return spring 112, and the distribution valves 46, 46 ... Can be reciprocated normally.

Referring again to FIGS. 1 and 2, the output shaft 25 is provided with an oil passage 63 having a deep stop at the center thereof, and the open end of the oil passage 63 has a side wall of the crankcase 4. The oil supply pipe 64 supported by is inserted. The oil supply pipe 64 communicates with the inside of an oil pan 69 at the bottom of the crankcase 4 via an oil passage 65 formed in the side wall of the crankcase 4, a filter 66 attached to the side wall, a reinforcing pump 67 and a strainer 68. The supply pump 67 is driven from the input member 5 via gears 70 and 71. Therefore, the 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 is a radial replenishment hole formed in the output shaft 25.
It communicates with the inner oil passage 40 via 72. Also the oil passage 63
A check valve 73 for preventing the reverse flow of oil to the supply pipe 64 is installed in the valve.

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

During reverse load operation, that is, during engine braking, the hydraulic motor M acts as a pump and the hydraulic pump P acts as a motor, so that the outer oil passage 41 is changed to a low pressure and the inner oil passage 40 is changed to a high pressure. The hydraulic oil tries to flow back from the passage 40 to the oil passage 63, but the backflow is blocked by the check valve 73. Therefore, the reverse load from the hydraulic motor M to the hydraulic pump P can be reliably transmitted, and a good engine braking effect can be obtained.

Incidentally, 74 and 75 in FIG. 1 are from the oil passage 63 to the plungers 9 and 19 and the swash plate 1.
In order to supply the lubricating oil to each contact part with 0, 20, the output shaft 25
It is an orifice hole formed in the.

C. Effects of the Invention As described above, according to the present invention, the pump cylinder of the hydraulic pump and the motor cylinder of the hydraulic motor are integrally coupled to the output shaft, and the discharge stroke of the hydraulic pump is provided between the pump cylinder and the motor cylinder. The annular high-pressure oil passage connected to the side cylinder hole and the annular low-pressure oil passage connected to the suction stroke side cylinder hole of the hydraulic pump are concentrically formed, and reciprocate between the radially outer position and the inner position. A large number of distribution valves that can alternately connect the many cylinder holes of the motor cylinder to the high-pressure oil passage and the low-pressure oil passage are arranged radially, and when the motor swash plate of the hydraulic motor is tilted, the pump cylinder rotates. An eccentric wheel is provided to reciprocate the distribution valve so that the expansion stroke side cylinder hole of the hydraulic motor communicates with the high pressure oil passage and the contraction stroke side cylinder hole of the hydraulic motor communicates with the low pressure oil passage. Since it is engaged with the valve, hydraulic oil can be transferred between the hydraulic pump and hydraulic motor without rotating the pump cylinder and motor cylinder relative to each other, and the reciprocating distribution valve has very little leakage of hydraulic oil. Therefore, the transfer of the hydraulic oil is reliable, and it can contribute to the improvement of the transmission efficiency.

Further, when the motor swash plate is in the upright state, the eccentric wheel is interlocked with the motor swash plate so that the reciprocating motion of the distribution valve is stopped to disconnect between the hydraulic motor and the low and high pressure oil passages. The hydraulic pump and the hydraulic motor can be mechanically connected to each other by giving the function of a valve, the transmission efficiency in the state of the gear ratio 1 can be further enhanced, and the dedicated lock-up valve is unnecessary. Therefore, the configuration is simple,
It can also contribute to cost reduction.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a vertical plan view of a hydrostatic continuously variable transmission interposed in a power transmission system of a motorcycle, and FIG. 2 is a vertical rear view of the transmission. , Fig. 3 is the second
III-III sectional drawing of the figure, FIG.4 and FIG.5 is IV of FIG.
-IV line and V-V line sectional view, FIGS.
5A to 7A are diagrams showing the thrust load distribution of the motor plunger group in the states of FIGS. 5 to 7, FIG. 9 is a perspective view of the first distributing valve, and FIG. FIG. 11 is a perspective view of the second distributing valve, FIG. 11 is a sectional view taken along line XI-XI of FIG. 4, FIG. 12 is a longitudinal sectional view of the shift control device, and FIG. 13 is XIII-XIII of FIG.
It is a line sectional view. e ... 1st eccentric position, h ... concentric position, P ... hydraulic pump, T ... continuously variable transmission, M ... hydraulic motor, 1 ... crankshaft, 5 ... input member, 7 ... pump Cylinder, 8 ... Its cylinder hole, 9 ... Pump plunger, 10 ... Pump swash plate, 17 ... Motor cylinder, 18 ...
The cylinder hole, 19 ... Motor plunger, 20 ... Motor swash plate, 25 ... Output shaft, 40 ... Inner oil passage as low pressure oil passage, 41 ... Outer oil passage as high pressure oil passage, 46 ... Second distribution valve as distribution valve, 49 ... Second eccentric wheel as eccentric wheel,
52 ... operating ring, 54 ... support member, 80 '... trunnion shaft, 83 ... second control lever, 110 ... support hole, 111 ... cam hole, 111a ... slope, 112 ... return spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Nakamura 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Keihiro Yoshida 1-4-1 Wako-shi, Saitama Incorporated company Honda R & D Co., Ltd. (72) Inventor Yoshihiro Nakajima 1-4-1 Chuo, Wako, Saitama Prefecture Incorporated Honda R & D Co., Ltd. (72) Inventor Mitsuru Saito 1-4-1 Wako, Saitama Prefecture (56) References JP 54-134252 (JP, A) British patent 745543 (GB, A)

Claims (1)

[Claims] 1. A hydrostatic continuously variable transmission in which a hydraulic closed circuit is formed between a swash plate hydraulic pump and a variable displacement swash plate hydraulic motor, wherein a pump cylinder of the hydraulic pump and a motor cylinder of the hydraulic motor are provided. An annular high-pressure oil passage that is integrally connected to the output shaft and that connects to the discharge stroke side cylinder hole of the hydraulic pump between the pump cylinder and the motor cylinder,
An annular low-pressure oil passage connected to the suction stroke side cylinder hole of the hydraulic pump is concentrically formed, and reciprocates between an outer position and an inner position in the radial direction to cause a large number of cylinder holes of the motor cylinder to form a high-pressure oil passage. And a plurality of distribution valves that can be alternately communicated with the low-pressure oil passage are arranged radially, and when the motor swash plate of the hydraulic motor is tilted, the distribution valve is reciprocated as the pump cylinder rotates, and An eccentric wheel for communicating the expansion stroke side cylinder hole with the high pressure oil passage and the contraction stroke side cylinder hole of the hydraulic motor with the low pressure oil passage is engaged with the distribution valve, and when the motor swash plate is upright, the distribution valve is connected. A hydrostatic continuously variable transmission characterized in that an eccentric wheel is interlocked with a motor swash plate so as to stop the reciprocating motion of the valve and disconnect between the hydraulic motor and the low and high pressure oil passages.