JPH0749826B2 - Shift control device for hydrostatic continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a hydrostatic continuously variable transmission in which a hydraulic closed circuit is formed between a swash plate hydraulic pump and a swash plate hydraulic motor. At
The present invention relates to an improvement of a shift control device that controls a displacement of a hydraulic motor by adjusting a tilt angle of a motor swash plate of the hydraulic motor in order to control a gear ratio.

(2) Conventional Technology Conventionally, it is known to connect a hydraulic servomotor to a motor swash plate so that the inclination angle of the motor swash plate can be adjusted easily (see Japanese Patent Publication No. 59-38467).

(3) Problems to be Solved by the Invention In the above conventional technique, the hydraulic servomotor has a complicated structure and is expensive, and thus there is a tendency that the cost becomes high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a low-cost gear shift control device by which the angle of a motor swash plate can be reliably adjusted with a relatively inexpensive small electric motor. To do.

B. Structure of the Invention (1) Means for Solving Problems In order to achieve the above object, the present invention forms a hydraulic closed circuit between a swash plate type hydraulic pump and a swash plate type hydraulic motor. In a hydrostatic stepless transmission in which a swash plate holder that supports the motor swash plate is pivotally supported in a casing so as to be tiltable around a predetermined tilt axis, the swash plate holder is mechanically connected to the swash plate holder while The operating lever fixed to the is linked to the piston slidably fitted to the fixed cylinder,
First and second oil chambers defined between the cylinder and the piston and opposed to each other with the piston interposed therebetween are communicated with each other via a hydraulic conduit, and the hydraulic conduit is provided with the conduit when the electric motor is at rest. Hold position for turning off the electric motor, a deceleration position for making the conduit conductive only in one direction from the first oil chamber to the second oil chamber when the electric motor rotates normally, and the conduit when the electric motor rotates reversely. Is provided with a control valve that can be selectively switched to a speed increasing position where the second oil chamber is connected to the first oil chamber only in one direction.

(2) Action When the electric motor is at rest, the control valve occupies the hold position and shuts off the hydraulic conduit, thus hydraulically locking the piston (and thus the swash plate holder via the actuating lever), and thus the electric motor. Despite the fact that the motor is mechanically connected to the swash plate holder, the motor swash plate can be securely held in the upright state or the inclined state without applying a reverse load to the electric motor.

During normal rotation of the electric motor, the control valve is switched to the speed increasing position and the hydraulic conduit is brought into conduction only in one direction from the first oil chamber to the second oil chamber, so that no reverse load is applied to the electric motor. This can be lightly rotated forward to raise the motor swash plate.

When the electric motor rotates in the reverse direction, the control valve switches to the deceleration position to bring the hydraulic conduit into conduction only in one direction from the second oil chamber to the first oil chamber. In this case as well, apply a reverse load to the electric motor. Without this, the motor swash plate can be tilted by simply reversing this.

(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 reduction gear 2, the hydrostatic continuously variable transmission T, and the chain type secondary reduction position 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 a large number of pump ports a, a ... Which mutually communicate the cylinder holes 8, 8 ... and the first valve holes 42, 42. Holes 18,18 ... and second valve holes 43,4
A large number of motor ports b, b ... Which communicate with each other are provided. 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. 5, and when it occupies the radially outer position 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 the pump is communicated with only the outer oil passage 41 and occupies 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. 4 and 6,
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, the notch 46a is formed into the inner oil passage 40 or the outer oil passage 41.
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. 4). 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'.

The second eccentric ring 49, as shown in FIG. 4, the eccentric position l eccentric along the tilt axis i.e. trunnion axis O ₂ of the motor swash plate 20 from the center of the output shaft 25 by a predetermined distance epsilon _2, the output shaft twenty five
Is controlled to a concentric position m which is concentric with.

Thus, when the second eccentric wheel 49 occupies the first eccentric position l,
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. When moving and occupying the concentric position m, the motor cylinder 17
.., all second distributing valves 49, 49 ... Are held 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 device 2 when the second eccentric shaft 49 occupies the eccentric position l, the pump swash plate 10 causes the pump plunger 9,
The intake stroke and the discharge stroke are alternately given to 9, and the one 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 '. The first distribution valve 45 adjacent to the pump plunger 9 entering the discharge stroke is operated to the outer 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 to a value of zero, 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.

2, FIG. 8, and FIG. 9, the trunnion shaft is shown.
A gear shift control device C for controlling the angle of the motor swash plate 20 is connected to 80. The shift control device C includes a sector gear 81 rotatably supported by a trunnion shaft 80,
A damper 82 that elastically connects the sector gear 81 to the trunnion shaft 80, and a worm gear 85 that is supported by a bracket plate 83 fixed to the crankcase 4 with bolts 150 via bearings 84 and 84 'and meshes with the sector gear 81. The worm gear 85 includes a direct-current / reverse-rotatable DC electric motor 86 that connects a drive shaft 86a to the worm gear 85, and a shift assist device Cs that assists the electric motor 86.
86b is fixed in place on the crankcase 4.

In the above, the sector gear 81 and the worm gear 85 can decelerate the rotation of the drive shaft 86a and transmit the rotation to the trunnion shaft 80. However, when a reverse load is applied from the trunnion shaft 80, the reduction gear R is configured.

The damper 82 has a fan-shaped buffer chamber 87 centered on the trunnion shaft 80 and a damper body 89 fixed to the trunnion shaft 80 with bolts 88, and a pair of rubber buffer members loaded in the buffer chamber 87. 90, 90 ', and a transmission piece 91 protruding from one side surface of the sector gear 81 is inserted between the cushioning members 90, 90'.

When the electric motor 86 is rotated normally or reversely, the rotation is decelerated and transmitted from the worm gear 85 to the sector gear 81, and further, via the transmission piece 91, the buffer member 90 or 90 ′, and the damper body 89. It can be transmitted to the trunnion shaft 80, and this can be rotated in the standing direction or the tilting direction of the motor swash plate 20. At that time, the electric motor 86 or the motor swash plate 20
The excessive torque acting on the buffer member is relaxed by the elastic deformation of the buffer members 90 and 90 '.

In order to restrict the standing position and tilting position of the motor swash plate 20 by the electric motor 86, the sector gear 81 is provided with an arcuate restriction groove 92 concentric therewith, and is slidably engaged with the restriction groove 92. A matching regulation collar 93 is fixed to the bracket 83 with a bolt 94.

As shown in FIGS. 10 and 11, the shift assist device Cs includes a cylinder 100 fixed to a proper position of the crankcase 4.
And a piston 101 slidably fitted on the cylinder 100. There is a window 102 on the side wall of the cylinder 100 and a piston 101.
A connecting hole 103 is formed in the central portion of the trunnion shaft 80 such that the connecting hole 103 penetrates it in the lateral direction and faces the window 102, and the operating lever 104 fixed to the trunnion shaft 80 is engaged with the connecting hole 103 through the window 102. The piston 101 is slid according to the rotation of the trunnion shaft 80.

Thus, in FIG. 10, the maximum tilt position and the upright position of the motor swash plate 20 are determined by the upper limit and the lower limit of the piston 101, and between the piston 101 and the lower end wall of the cylinder 100. A first oil chamber 105 ₁ is defined, and a second oil chamber 105 ₂ is defined between the piston 101 and the upper end wall of the cylinder 100.
A return spring 106 for urging the piston 101 toward the second oil chamber 105 ₂ side is contracted at 105 ₁ .

The first and second oil chambers 105 ₁ and 105 ₂ are communicated with each other via a hydraulic conduit 108 in which a control valve 107 is interposed, and the inside thereof is filled with hydraulic oil.

The control valve 107 is a valve box 109 that is installed at an appropriate position of a vehicle control device and intervenes in the middle of the hydraulic conduit 108, and this valve box 109.
First and second check valves 111 which are installed in series in the oil passage 110 in
Composed of _1, 111 _2. These first and second check valves 11
1 ₁ and 11 ₁₂ are arranged such that the forward directions are opposite to each other, and are always biased in the valve closing direction by valve springs 112 ₁ and 112 ₂ , respectively.

The first and second check valves 111 ₁ and 111 ₂ are provided with the first and second check valves 111 ₁ and 111 ₂ as the first and second actuators so that they can be forcibly opened at appropriate times.
And the operating rods 113 ₁ and 113 _{2 of} the second electromagnetic actuators S ₁ and S ₂ are connected to each other. The first and second electromagnetic actuators S ₁ and S ₂ are movable iron cores 114 ₁ and 114 ₂ integrally provided with the above-mentioned operating rods 113 ₁ and 113 _{2 at} their tips.
And a solenoid 115 surrounding these movable iron cores 114 ₁ and 114 _2.
1 and 115 ₂ and these solenoids 115 ₁ and 115 ₂ are held and the valve box 1
Actuator body 11 fixed to 09 with bolts 116 and nuts 117
8 ₁ , 118 ₂ , return springs 119 ₁ , 119 ₂ for biasing the movable iron cores 114 ₁ , 114 ₂ toward the upper inoperative position, and bolts for the valve box 109.
It is composed of a common stopper plate 121 which is fixed at 120 and regulates the inoperative positions of the movable iron cores 114 ₁ and 114 ₂ .

In the first and second electromagnetic actuators S ₁ and S ₂ , when the solenoids 115 ₁ and 115 ₂ are demagnetized, the movable iron cores 114 ₁ and 114 ₂ are held in the inoperative position by the force of the return springs 119 ₁ and 119 _2. Accordingly, the operating rods 113 ₁ and 113 ₂ are separated from the first and second check valves 111 ₁ and 111 ₂ , so that the first and second check valves 111 ₁ and 111 ₂ can be kept closed. it can. If exciting the solenoid 115 _1, 115 _2, so moves downward against the movable iron core 114 _1, 114 ₂ return spring 119 _1, 119 ₂ of the force by the action of the magnetic force, actuating rod 113 _1,
113 ₂ allows the first and second check valves 111 ₁ and 111 ₂ to be forcibly opened. And Thus, the solenoid 115 of the _first electromagnetic actuator S ₁ is excited during forward rotation of the electric motor 86, the solenoid 115 of the _second electromagnetic actuator S ₂ is adapted to be energized during the reverse rotation of the electric motor 86 ing.

By the way, since the number of motor plungers 19, 19 ... Is an odd number, the thrust load exerted on the motor swash plate 20 by the motor plungers 19, 19 ... Group during rotation of the motor cylinder 17 is the trunnion axis O of the motor swash plate 20. _The strength changes alternately between the one side and the other side at the boundary of _2, and a vibrational tilting torque acts on the motor swash plate 20. Then, this oscillating tilting torque acts as a pressing force alternately on the piston 101 in the vertical direction in FIG. 10 via the operating lever 104.

Therefore, if degauss both electromagnetic actuator S _1, the solenoid 115 ₁ S _2, 115 ₂ when the rest of the electric motor 86, Ryogyakutomeben 111 _1, 111 ₂ which is closed cooperate Since the oil is completely blocked in the valve box 109, the piston 101 is hydraulically locked, and the operating lever 104 is held at that position, and the motor swash plate 20 is held in the upright position or the inclined position. be able to. As a result, the reduction gear R from the motor swash plate 20
Also, it is possible to prevent the reverse load from being transmitted to the electric motor 86.

Further, when only the solenoid 115 ₁ of the first electromagnetic actuator S ₁ is excited during the forward rotation of the electric motor 86, the first check valve 111 ₁ is opened, so that the second check valve 111 ₂ is used. 1st oil chamber 105 ₁
The flow of oil from the second oil chamber 105 ₂ is allowed, but the flow in the opposite direction is blocked. As a result, only the downward movement of the piston 101 (FIG. 10), and therefore the standing motion of the motor swash plate 20, is allowed, so that the oscillatory tilting moment of the motor swash plate 20 acts in the standing direction of the motor swash plate 20. Only the moment assists the forward rotation torque of the electric motor 86, and the forward rotation of the electric motor 86 allows the motor swash plate 20 to be easily raised.

On the contrary, when the electric motor 86 rotates in the reverse direction, the second electromagnetic actuator
Since the second check valve 111 ₂ is an open state when energized only solenoid 115 ₂ S _2, the first check valve 111 ₁ from the second oil chamber 105 ₂ to the first oil chamber 105 ₁ Oil flow is allowed,
Flow in the opposite direction is blocked. As a result, the piston
Since only the upward movement of 101 (FIG. 10) and therefore the tilting motion of the motor swash plate 20 are allowed, only the moment acting in the tilting direction of the motor swash plate 20 out of the vibrational tilting moment of the motor swash plate 20 is electrically driven. Since the reverse rotation torque of the motor 86 is assisted, the reverse rotation of the electric motor 86 can tilt the motor swash plate 20 lightly.

In FIG. 11, a reserve tank 130 is installed above the cylinder 100, and the reserve tank 130 is used as a cylinder.
Relief port 131 and supply port communicating within 100
132 is drilled in the upper wall of the cylinder 100.

First and second cup seals 133 and 134 having a one-way sealing function that are in close contact with the inner peripheral surface of the cylinder 100 are mounted on the outer circumferences of both ends of the piston 101, and the inner circumference of the cylinder 100 includes the left and right sides of the window 102. On both sides, O-rings 135 and 136 are attached which are in close contact with the outer peripheral surface of the intermediate portion of the piston 101.

Thus, the relief port 131 opens to the first oil chamber 105 ₁ immediately before the first cup seal 133 when the piston 101 is located at the left limit (upper limit in FIG. 10) in FIG. The supply port 132 is always open on the inner surface of the cylinder 100 between the second cup seal 134 and the O-ring 136.

Therefore, when the piston 101 is located in the left limit, if a pressure rise occurs in the first oil chamber 105 ₁ due to a rise in oil temperature or the like, the pressure is released from the relief port 131 to the reserve tank 130. When the piston 101 moves to the right, the first oil chamber 105 ₁ is pressurized by the piston 101 from when the first cup seal 133 passes through the opening of the relief port 131, and the first oil chamber 105 ₁ moves to the second oil chamber 105 ₁ . Allows oil flow to 105 ₂ . At this time, if the second hydraulic chamber 105 ₂ is depressurized to a predetermined pressure or less, the oil in the reserve tank 130 will flow from the supply port 132 to the cylinder 100 and the cylinder 100 due to the pressure difference between the reserve tank 130 and the second oil chamber 105 _2. It passes through the sliding gap of the piston 101 and is replenished into the chamber 105 ₂ while the second cup seal 134 is deflected toward the second oil chamber 105 ₂ .

In FIGS. 2 and 4, the second eccentric ring 49 is rotatably supported by the operating ring 140 via a bearing 50. The actuating ring 140 has a pair of ears 141 and 141 'on both sides of the trunnion axis O ₂ direction, U-shaped guide groove 142 extending in the direction of the trunnion axis O ₂ is formed on one of the ears 141 , A guide pin 143 slidably inserted in the guide groove 142
Is fixed to the crankcase 4. The other ear 14
A guide shaft 144 is continuously provided at the tip of 1 ', and a guide hole 145 for sliding the guide shaft 144 along the trunnion axis O ₂ is formed in the crankcase 4. In this way, the operating ring 140 can be displaced in the direction of the trunnion axis O ₂ , and this displacement can control the second eccentric wheel 49 to the eccentric position 1 and the concentric position m.

In the guide hole 145, the operating ring 140 is attached to the eccentric position l of the second eccentric ring 49.
The return spring 146 is contracted so as to spring toward.

Further, a cam hole 147 is provided in the ear portion 141 ', and a control lever 148 fixed to the trunnion shaft 80' is inserted into the cam hole 147. An inner surface of the cam hole 147 on the guide shaft 144 side is a slope 147a that engages with the control lever 148, and is pressed by the control lever 148 in conjunction with the standing motion of the motor swash plate 20. According to the pressing, the operating ring 14
0 displaces against the force of the return spring 146 to displace the second eccentric wheel 49 from the eccentric position 1 toward the concentric position m, and when the motor swash plate 20 is upright, the second eccentric wheel 49 is displaced. control to m.

When the second eccentric wheel 49 reaches the concentric position m, all the second distribution valves 46, 46 ... Are closed as shown in FIG. 4A, 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, and therefore the gear ratio 1
The transmission efficiency in the state of can be improved.

In this case, in the illustrated example, the displacement of the second eccentric wheel 49 to the concentric position m is performed steplessly by the action of the sloping surface 147a of the cam hole 147 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 it is possible to prevent the shift shock from occurring when the valve is closed. 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.

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. This 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 mounted on the side wall, a replenishment 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 oil supply pipe 64 is interposed 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 uses a pump action and the hydraulic pump P performs a motor action, so that the outer oil passage 41 changes to a low pressure and the inner oil passage 40 changes 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, since the drive shaft of the electric motor capable of forward and reverse rotation is mechanically connected to the swash plate holder, the swash plate holder is mechanically driven by the drive torque of the electric motor. Therefore, compared with the case where the tilt angle of the motor swash plate is adjusted by the hydraulic servo mechanism, the structure of the entire drive control system from the electric motor to the swash plate holder is simplified and the cost is reduced. In addition, it is possible to accurately adjust the tilt angle of the motor swash plate with excellent responsiveness,
In particular, a shift control device suitable for vehicles can be obtained.

In addition, an operating lever fixed to the swash plate holder is interlocked with a piston slidably fitted in a fixed cylinder, and the first and the first cylinders defined between the cylinder and the piston are opposed to each other with the piston interposed therebetween. The second oil chamber is communicated with each other via a hydraulic conduit, and the hydraulic conduit is connected to a hold position for shutting off the conduit when the electric motor is at rest, and the conduit from the first oil chamber when the electric motor is rotating forward. (2) Selective in the deceleration position where it is conductive only in one direction to the oil chamber, and in the speed increasing position where the conduit is made conductive only in one direction from the second oil chamber to the first oil chamber when the electric motor reverses. Since a control valve that can switch to
When the electric motor is at rest, the control valve in the hold position can hydraulically lock the piston (and thus the swash plate holder via the actuating lever), so that the electric motor is in mechanical connection with the swash plate holder. Nevertheless, the swash plate of the motor can be securely held in the upright state or the inclined state without applying any reverse load to the electric motor, and the electric motor can be downsized. Further, when the electric motor is rotating in the normal direction or in the reverse direction, the control valve in the deceleration position or the speed increasing position can easily rotate the electric motor in the normal direction or the reverse direction without applying a reverse load to the electric motor by the one-way communication action. There is no fear that the above-mentioned effects due to the mechanical connection of the motor to the swash plate holder will be impaired. Moreover, the cylinder is
It is merely used for hydraulically locking the swash plate holder when the electric motor is at rest, and it is not necessary to connect a hydraulic pressure source to the swash plate holder, so that the cylinder and the control valve are included. Even if the hydraulic circuit is specially installed, the cost increase can be suppressed as much as possible and its control is easy.

[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. 3 and 4 are cross-sectional views taken along the lines III-III and IV-IV of FIG. 2, FIG. 4A is an operation explanatory view of FIG. 4, and FIG. 5 is a perspective view of the first distribution valve.
FIG. 6 is a perspective view of the second distributing valve, and FIG. 7 is VII-V of FIG.
II sectional view, FIGS. 8 and 9 are sectional views taken along the line VIII-VIII and IX-IX in FIG. 2, FIG. 10 is a longitudinal sectional front view of the shift assist device, and FIG. 11 is XI of FIG. It is a XI line sectional view. C ... shift control device, Cs ... shift assist device, P ... hydraulic pump, T ... continuously variable transmission, M ... hydraulic motor, 4 ...
Crankcase as casing, 7 ... Pump cylinder, 9 ... Pump plunger, 10 ... Pump swash plate, 17
...... Motor cylinder, 19 ...... Motor plunger, 20 ......
Motor swash plate, 22 ... swash plate holder, 80, 80 '... trunnion shaft, 86 ... electric motor, 100 ... cylinder, 101 ... piston, 104 ... actuating lever, 105 ₁ , 105 ₂ ... 1, second oil chamber, 107 ... control valve, 108 ... hydraulic conduit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Kobayashi 1-4-1 Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. No. 1 Inside Honda R & D Co., Ltd. (72) Inventor Kazuhiko Nakamura 1-4-1, Chuo, Wako-shi, Saitama Inside R & D Laboratories Co., Ltd. (72) In-house Yoshihiro Nakajima 1-4-4 Wako, Saitama No. 1 inside Honda R & D Co., Ltd. (72) Inventor Yoshihiro Yoshida 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (56) Reference JP-A-61-55375 (JP, A)

Claims (2)

[Claims] 1. A swash plate holder for supporting a motor swash plate (20) of a hydraulic motor (M) by forming a closed hydraulic circuit between the swash plate hydraulic pump (P) and the swash plate hydraulic motor (M). twenty two)
In a hydrostatic stepless transmission in which a casing (4) is pivotally supported so as to be tiltable around a predetermined tilt axis (O ₂ ), the swash plate holder (22) is equipped with an electric motor (8
The drive shaft (86a) of 6) is mechanically connected, while the operating lever (104) fixed to the swash plate boulder (22) is slidably fitted in a fixed cylinder (100) (a piston (100)). 101)
These cylinder (100) and piston (10
1) The first and second oil chambers (105 ₁ , 105 ₂ ) defined between the first and second oil chambers (105, 105 ₂ ) opposed to each other with the piston (101) interposed therebetween are communicated with each other through a hydraulic conduit (108), (108) includes a hold position for shutting off the conduit (108) when the electric motor (86) is at rest, and a conduit for holding the conduit (108) when the electric motor (86) is in the normal rotation (the first oil chamber ( 105 ₁ ) to the second oil chamber (10
5 ₂ ) The deceleration position in which the electric connection is established only in one direction, and when the electric motor (86) rotates in the reverse direction, the conduit (108) is set to the second position.
A control valve (10) that can be selectively switched to a speed increasing position in which the oil chamber (105 ₂ ) is electrically connected only in one direction from the oil chamber (105 ₂ ) to the first oil chamber (105 ₁ ).
7) A transmission control device for a hydrostatic continuously variable transmission, characterized in that 2. The control valve (107) is connected to the hydraulic conduit (10).
8) is installed in the first oil chamber (105 ₁ ) to the second oil chamber (10
5 ₂ ) and a first check valve (111 ₁ ) for blocking the flow of oil to the hydraulic check pipe (10 ₁ ) in series with the first check valve (111 ₁ ).
8) is installed in the second oil chamber (105 ₂ ) to the first oil chamber (10
The second check valve (111 ₂ ) that blocks the flow of oil to 5 ₁ ) and the first check valve (111 ₁ ) when the electric motor (86) rotates forward.
The provided first actuator to force open the (115 _1), second actuator to force open the second check valve (111 ₂₎ during reverse rotation of the electric motor (86) and (115 ₂₎ A shift control device for a hydrostatic continuously variable transmission according to claim 7.