JP2011208717A - Hydrostatic continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an output shaft reversely rotating means in a hydrostatic continuously variable transmission including: a hydraulic pump formed of a plurality of plungers provided in cylinders, and a hydraulic motor respectively provided between two swash plates; a hydraulic circuit provided between the plunger of the hydraulic pump and the plunger of the hydraulic motor and including a high-pressure oil passage feeding an operating fluid from the hydraulic pump to a hydraulic motor side, a low-pressure oil passage feeding the operating fluid from the hydraulic motor side to a hydraulic pump side, and a hydraulic selector valve, which switches the plunger to the high-pressure oil passage or the low-pressure oil passage by abutting on the inner peripheral surface of an eccentric cam ring and reciprocating in the radial direction of a valve body; and a lock-up mechanism, which changes a speed ratio by tilting at least one of the swash plates and which closes the hydraulic circuit by displacing the eccentric cam ring by the actuator.SOLUTION: The actuator further drives the eccentric cam ring to displace it in a direction reverse to the direction in the normal operation to rotate an output shaft in a direction reverse to the inputting rotating direction.

Description

  The present invention relates to a hydrostatic continuously variable transmission, and more particularly, to a means for reversely rotating an output shaft of a transmission for backward traveling of a vehicle.

  Patent Document 1 discloses a lockup control mechanism, but does not disclose output shaft reverse rotation means.

JP 2008-249099 A

  The present invention intends to provide an output shaft reverse rotation means in a hydrostatic continuously variable transmission.

The present invention solves the above problems, and the invention according to claim 1
Between the two swash plates 9 and 22, a hydraulic pump 2 composed of a plurality of plungers 12 provided in the cylinder 10 and a hydraulic motor 3 composed of a plurality of plungers 25 provided in another cylinder 23 are provided. A high pressure oil passage 61 for sending hydraulic oil from the hydraulic motor 3 side to the hydraulic motor 3 side, a low pressure oil passage 60 for sending hydraulic oil from the hydraulic motor 3 side to the hydraulic pump 2 side, and the inner peripheral surfaces of the eccentric cam rings 51 and 52 The hydraulic circuit including the hydraulic switching valves 47 and 48 that reciprocate in the radial direction of the valve body 33 and switch the correspondence between the plungers 12 and 25 and the high-pressure oil passage 61 or the low-pressure oil passage 60. A hydraulic circuit is provided between the plunger 12 and the plunger 25 of the hydraulic motor 3 and tilts at least one of the swash plates 9 and 22 to change the gear ratio, and the eccentric cam ring 52 is eccentric by an actuator 66. Close In hydrostatic continuously variable transmission 1 provided with a lock-up mechanism that,
The eccentric cam ring 52 is further driven by the actuator 66 and is eccentric in the direction opposite to that during normal operation, thereby rotating the output shaft 6 in the direction opposite to the input rotation direction. The present invention relates to a continuously variable transmission 1.

The invention according to claim 2 is the hydrostatic continuously variable transmission 1 according to claim 1,
The lock-up mechanism is provided with the eccentric cam ring 52 so as to be rotatable about a rotation center 56 provided outside the eccentric cam ring 52, and at the opposite side of the eccentric cam ring 52 to the rotation center 56. Is driven by the actuator 66.

The invention according to claim 3 is the hydrostatic continuously variable transmission 1 according to claim 1 or 2,
The actuator 66 is a hydraulic actuator 66 provided with an actuator control device capable of two-stage control.

According to a fourth aspect of the present invention, in the hydrostatic continuously variable transmission 1 according to any one of the first to third aspects,
The actuator control device is provided with means for prohibiting the operation of the actuator 66 for switching to the reverse rotation of the output shaft 6 when the cylinder 23 is rotating.

The invention according to claim 5 is the hydrostatic continuously variable transmission 1 according to any one of claims 1 to 4,
When the gear ratio is less than a predetermined value before the output shaft 6 is reversely rotated, the means for changing the inclination angle of the swash plates 9 and 22 to change the gear ratio to a predetermined value or more, or the reverse rotation of the output shaft 6 Means is provided for prohibiting the operation of the hydraulic actuator 66 for switching.

In the invention of claim 1,
A mechanism that reversely rotates the output shaft 6 can be configured with a simple configuration.

In the invention of claim 2,
The output shaft 6 reverse rotation mechanism can be configured with a simple configuration.

In the invention of claim 3,
With the hydraulic actuator 66, it is possible to easily realize the two-stage operation of lock-up and reverse rotation of the output shaft 6.

In the invention of claim 4,
Since it can prevent switching to the output shaft 6 reverse rotation at the time of forward rotation, it is safe.

In the invention of claim 5,
The engine stop at the time of reverse rotation of the output shaft 6 can be prevented.

1 is a longitudinal sectional view of a hydrostatic continuously variable transmission 1 according to an embodiment of the present invention. 2 is an enlarged longitudinal sectional view of the vicinity of a distribution valve 4 of the hydrostatic continuously variable transmission 1. FIG. FIG. FIG. 4 is a view of a retainer ring 39. 3 is a view of a C-shaped clip 40. FIG. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 3 is a cross-sectional view of a motor servo mechanism 28 that changes the angle of a motor swing member 21. FIG. 4 is a cross-sectional view showing a state where the motor swing member 21 is upright by the motor servo mechanism 28 (the rotation surface of the swash plate is orthogonal to the output shaft). FIG. FIG. 6 is a cross-sectional view of the vicinity of a motor eccentric annular member 55 and a motor side eccentric cam ring 52 when the amount of eccentricity becomes zero. FIG. 5 is a view showing a state where a motor eccentric annular member 55 is driven to rotate rightward in the drawing for backward drive. FIG. 2 is a longitudinal sectional view of the vicinity of a centrifugal governor clutch 5. 1 is a longitudinal sectional view of a main part of a hydrostatic continuously variable transmission 1 showing a supply path of hydraulic oil and lubricating oil.

  FIG. 1 is a longitudinal sectional view of a hydrostatic continuously variable transmission 1 according to an embodiment of the present invention. The transmission 1 is used by being connected to an internal combustion engine mounted on a vehicle. The output of the transmission 1 is used for driving wheels via a plurality of gears. The hydrostatic continuously variable transmission 1 includes a swash plate plunger hydraulic pump 2, a swash plate plunger hydraulic motor 3, a distribution valve 4, and a centrifugal governor clutch 5. The hydrostatic continuously variable transmission 1 An output shaft 6 serving as an output shaft is disposed through the center. The left end of the output shaft 6 is rotatably supported by the transmission housing 7 by ball bearings B1 and B2, and the right end is rotatably supported by the transmission housing 7 by ball bearings B3.

  On the left side from the center of the figure, the hydraulic pump 2 is disposed at a predetermined angle with respect to the output shaft 6 inside the pump casing 8 and the pump casing 8 disposed coaxially with the output shaft 6 so as to be relatively rotatable. A pump swash plate 9, a pump cylinder 10 disposed to face the pump swash plate 9, a plurality of pump plunger holes 11 arranged in an annular shape surrounding the output shaft 6 in the pump cylinder 10, The pump plunger hole 11 includes a plurality of pump plungers 12 slidably disposed. One end of the pump casing 8 is rotatably supported by the output shaft 6 by a bearing B2 and the other end of the pump casing 8 by a bearing B4. The pump casing 8 is rotatably supported by the transmission housing 7 by a bearing B1. ing. The pump swash plate 9 is disposed so as to be rotatable relative to the pump casing 8 at a predetermined angle by bearings B5 and B6.

  A transmission input gear 14 fastened by a bolt 13 is attached to the outer periphery of the pump casing 8. The outer end of the pump plunger 12 protrudes outward from the pump cylinder 10 and is in contact with and engaged with a recess in the swash plate surface 9a of the pump swash plate 9. An inner end portion of the pump plunger 12 forms a pump oil chamber 15 in the pump plunger hole 11. A pump opening passage 16 that functions as a discharge port and a suction port is formed at the end of the pump plunger hole 11. When the transmission input gear 14 is driven to rotate, the pump casing 8 rotates, and the pump swash plate 9 disposed therein swings three-dimensionally as the pump casing 8 rotates, and the pump plunger 12 tilts. The pump plunger hole 11 is reciprocated in accordance with the swing of the plate surface 9a, and the hydraulic oil in the pump oil chamber 15 is discharged or sucked.

  On the right side from the center of the figure, the casing 17 of the hydraulic motor 3 is coupled to the transmission housing 7 and fixedly held. The motor casing 17 includes a spherical member 18 and an extension member 19 and is connected by a bolt 20. A support spherical surface 18 a is formed on the inner surface of the spherical member 18. The hydraulic motor 3 includes a motor casing 17, a motor swing member 21 supported by sliding contact with the support spherical surface 18a, and a motor swash plate 22 rotatably supported by bearings B7 and B8 in the motor swing member 21. A motor cylinder 23 facing the motor swash plate 22, a plurality of motor plunger holes 24 arranged in an annular shape surrounding the rotation center line in the motor cylinder 23, and slidable in the motor plunger hole 24 A plurality of motor plungers 25 are provided. The motor cylinder 23 is rotatably supported by the extension member 19 of the motor casing 17 via a bearing B9 on the outer periphery thereof. The motor swinging member 21 is supported so as to swing about a rotation center O extending in a direction perpendicular to the center line of the output shaft 6 (a direction perpendicular to the paper surface).

  The outer end portion of the motor plunger 25 protrudes outward from the motor cylinder 23 and is brought into contact with and engaged with the concave portion of the swash plate surface 22a of the motor swash plate 22. An oil chamber 26 is formed. A motor opening passage 27 that functions as a discharge port and a suction port is formed at the end of the motor plunger hole 24. A tip end of an arm portion 21 a formed to protrude outward from the upper portion of the motor swing member 21 is connected to a ball nut 29 of a motor servo mechanism 28, and a ball screw shaft 30 is inserted into the ball nut 29. When the ball screw shaft 30 is rotationally driven by the motor servo mechanism 28, the ball nut 29 moves, the arm portion 21a moves to the left and right, and the motor swing member 21 rotates about the rotation center O in the figure. When the motor swinging member 21 rotates, the motor swash plate 22 rotatably supported therein also rotates about the rotation center O, and the swash plate angle changes.

  FIG. 2 is an enlarged longitudinal sectional view of the vicinity of the distribution valve 4 of the hydrostatic continuously variable transmission 1. A distribution valve 4 is disposed between the pump cylinder 10 and the motor cylinder 23. The valve body 33 of the distribution valve 4 is sandwiched between the pump cylinder 10 and the motor cylinder 23, and is integrally coupled to these cylinders by brazing. The motor cylinder 23 is coupled to the output shaft 6 by a spline 34. Therefore, the pump cylinder 10, the distribution valve 4, and the motor cylinder 23 rotate integrally with the output shaft 6. The pump cylinder 10, the valve body 33, and the motor cylinder 23 that are integrally coupled are collectively referred to as an output rotating body R. An axial positioning structure when the output rotating body R is attached to the output shaft 6 will be described. A large-diameter portion 36 having a short axial length is formed on the outer peripheral side of the output shaft 6 corresponding to the left end position of the pump cylinder 10. The left end surface of the pump cylinder 10 comes into contact with the end surface of the large diameter portion 36, and positioning in the left direction is performed.

  3, 4, and 5 are diagrams of members used for positioning the right side of the output rotating body R. FIG. In each figure, the figure (a) is an axial front view, and the figure (b) is a BB cross-sectional view of the figure (a). Positioning of the output rotator R on the right side is performed by a locking member attached to the output shaft 6 in contact with the end surface of the motor cylinder 23. This locking member includes a cotter 38, a retainer ring 39, and a C-shaped clip 40. An annular first locking groove 41 and a second locking groove 42 are formed in the output shaft 6 across the outer spline 34 for mounting the locking member. A pair of cotters 38 divided and formed in a semicircular shape shown in FIG. A retainer ring 39 shown in FIG. 4 is mounted thereon. The retainer ring 39 covers the cotter 38, and a C-shaped clip 40 shown in FIG. 5 is attached to the second locking groove 42 to prevent the retainer ring 39 from coming off. As a result, the right end surface of the motor cylinder 23 comes into contact with the locking member and positioning in the right direction is performed.

  As described above, the output rotator R is positioned and integrated with respect to the output shaft 6 by the spline 34 in the circumferential direction, by the large diameter portion 36 in the left direction, and by the locking members 38, 39, and 40 in the right direction. , Rotate with the output shaft 6. The retainer ring 39 is provided with three lubricating oil injection nozzles 39a on the entire circumference (FIG. 4).

  In FIG. 2, a plurality of pump-side valve holes 45 and motor-side valve holes 46 that are arranged at equal intervals in the circumferential direction and extend in the radial direction are formed in two rows in the valve body 33 constituting the distribution valve 4. Has been. A pump-side switching valve 47 is slidably disposed in the pump-side valve hole 45, and a motor-side switching valve 48 is slidably disposed in the motor-side valve hole 46.

  The pump side valve hole 45 is formed at a position corresponding to the pump plunger hole 11. A plurality of pump side communication passages 49 are provided in the valve body 33. This communicates each pump side valve hole 45 and each pump opening passage 16 of the pump plunger hole 11 respectively. The motor side valve hole 46 is formed at a position corresponding to the motor plunger hole 24. A plurality of motor side communication paths 50 are provided in the valve body 33. This communicates each motor side valve hole 46 and each motor opening passage 27 of the motor plunger hole 24, respectively.

  In the distribution valve 4, a pump side eccentric cam ring 51 is disposed at a position surrounding the outer peripheral end of the pump side switching valve 47, and a motor side eccentric cam ring 52 is disposed at a position surrounding the outer peripheral end of the motor side switching valve 48. Yes. The pump side eccentric cam ring 51 is attached to the inner periphery of the pump eccentric annular member 53. The pump eccentric annular member 53 is connected to the end of the pump casing 8 by a bolt 54 (FIG. 1). The motor side eccentric cam ring 52 is attached to the inner periphery of the motor eccentric annular member 55. The motor eccentric annular member 55 is rotatably coupled to the extension member 19 of the motor casing 17 by a pin 56 (FIG. 1). The outer end of the pump-side switching valve 47 is slidably engaged with the inner peripheral surface of the pump-side eccentric cam ring 51 via a pump-side regulating ring 57, and the motor-side eccentric cam ring 52 has a motor on the inner peripheral surface. An outer end of the side switching valve 48 is slidably locked via a motor side regulating ring 58. On either the pump side or the motor side, the eccentric cam rings 51 and 52 and the regulating rings 57 and 58 are relatively rotatable.

  On the outer peripheral surface of the output shaft 6 facing the inner peripheral surface of the valve body 33, an annular recess that acts as the low-pressure oil passage 60 is cut. The output shaft side opening ends of all the pump side valve holes 45 and the output shaft side opening ends of the motor side valve holes 46 communicate with the low pressure oil passage 60.

  A high pressure oil passage 61 is formed near the outer periphery of the valve body 33. The high pressure oil passage 61 includes an axial through hole 61a that communicates the pump side valve hole 45 and the motor side valve hole 46, a pump side annular communication groove 61b that communicates all the pump side valve holes 45 in an annular shape, and all A motor-side annular communication groove 61c that communicates with the motor-side valve hole 46 in an annular shape. The plurality of holes 61a and the grooves 61b and 61c communicate with each other to form a high-pressure oil passage 61.

  Here, the operation of the distribution valve 4 will be described. When the driving force of the internal combustion engine is transmitted to the transmission input gear 14 and the pump casing 8 rotates, the pump swash plate 9 swings three-dimensionally according to this rotation. The pump plunger 12 abutted and engaged with the swash plate surface 9 a of the pump swash plate 9 reciprocates in the pump plunger hole 11 in the axial direction by the three-dimensional swing of the pump swash plate 9. When the pump plunger 12 moves inward, hydraulic oil is discharged from the pump oil chamber 15 through the pump opening passage 16, and when the pump plunger 12 moves outward, the hydraulic oil passes through the pump opening passage 16 into the pump oil chamber 15. Inhaled.

In describing the moving direction and position of the pump plunger 12 and the motor plunger 25, the following definitions will be used.
With respect to the movement of the pump plunger 12 and the motor plunger 25, the movement toward the center with the distribution valve body 33 as the center is the inward movement, and the movement away from the center is the outward movement.
With respect to the positions of the pump plunger 12 and the motor plunger 25, with the distribution valve body 33 as the center, the position closest to the center is the inner end position, and the position farthest from the center is the outer end position.

  When the pump casing 8 rotates, the pump side eccentric cam ring 51 attached to the inner peripheral surface of the pump eccentric annular member 53 rotates together with the pump casing 8. The center of the pump side eccentric cam ring 51 is eccentric with respect to the rotation center of the pump casing 8. That is, since it is also eccentrically attached to the valve body 33, the pump side switching valve 47 reciprocates in the pump side valve hole 45 in the radial direction in accordance with the rotation of the pump side eccentric cam ring 51.

  Thus, when the pump side switching valve 47 reciprocates and moves radially inward in the valve body 33, the pump side communication passage 49 opens radially outward by the small diameter portion 47a of the pump side switching valve 47. The pump opening passage 16 and the high-pressure oil passage 61 communicate with each other. Conversely, when the pump side switching valve 47 moves radially outward in the valve body 33, the pump side communication passage 49 opens radially inward, and the pump opening passage 16 and the low pressure oil passage 60 communicate with each other.

  As the pump casing 8 rotates, the pump swash plate 9 swings, and the pump plunger 12 reciprocates between a position where the pump plunger 12 is pushed outward and a position where the pump plunger 12 is pushed most inward. Thus, the pump side eccentric cam ring 51 reciprocates the pump side switching valve 47 in the radial direction. As a result, when the pump plunger 12 moves inward as the pump casing 8 rotates, the hydraulic oil in the pump oil chamber 15 is discharged from the pump opening passage 16. At this time, since the eccentric mounting position of the pump side eccentric cam ring 51 is determined so that the pump opening passage 16 communicates with the high pressure oil passage 61, the hydraulic oil is sent to the high pressure oil passage 61. On the other hand, when the pump plunger 12 moves outward as the pump casing 8 rotates, the hydraulic oil in the low pressure oil passage 60 passes through the pump opening passage 16 and enters the pump oil chamber 15, contrary to the above. Inhaled. That is, when the pump casing 8 is driven to rotate, the hydraulic oil discharged from the pump oil chamber 15 on one side across the output shaft 6 is supplied to the high-pressure oil passage 61, and on the opposite side across the output shaft 6 The hydraulic oil is sucked into the pump oil chamber 15 from the low pressure oil passage 60.

  FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 1, and is a cross-sectional view of the vicinity of the motor eccentric annular member 55 and the motor side eccentric cam ring 52 during normal vehicle advancement. This figure is a view seen toward the motor cylinder 23, and shows the motor eccentric annular member 55 in the forward rotation state of the output shaft 6. The motor eccentric annular member 55 is rotatably coupled to the end of the extension member 19 of the motor casing 17 (FIG. 1) by a pin 56. The center B of the motor-side eccentric cam ring 52 attached to the inner peripheral surface of the motor eccentric annular member 55 is the transmission center plane C (ball screw shaft 30) when the motor eccentric annular member 55 is in the normal position (position shown in FIG. 6). And a plane passing through the center of the output shaft 6). That is, the center B of the motor side eccentric cam ring 52 is located on the left side of the rotation center A of the valve body 33. Since the motor-side switching valve 48 is always in contact with the inner periphery of the motor-side eccentric cam ring 52 by the motor-side regulating ring 58, when the motor cylinder 23 rotates, the motor-side switching valve 48 changes according to the rotation. Reciprocates radially inside 46.

  As shown on the right side of the center plane C in FIG. 6, when the motor side switching valve 48 moves radially inward in the valve body 33, the motor side communication path 50 is formed by the small diameter portion 48 a of the motor side switching valve 48. Since the motor opening passage 27 (FIG. 2) and the high pressure oil passage 61 communicate with each other, the hydraulic oil is opened from the high pressure oil passage 61 to the motor oil chamber 26 (FIG. 2). Sent. As shown on the left side of the center plane C in FIG. 6, when the motor side switching valve 48 moves radially outward in the valve body 33, the motor side communication passage 50 opens radially inward and the low pressure oil passage 60. Since the motor opening passage 27 (FIG. 2) and the low pressure oil passage 60 communicate with each other, the hydraulic oil is returned from the motor oil chamber 26 to the low pressure oil passage 60.

  The hydraulic oil discharged from the hydraulic pump 2 is sent to the high-pressure oil passage 61, and this hydraulic oil is supplied into the motor oil chamber 26 through the motor side communication passage 50 and the motor opening passage 27, and the motor plunger 25 is axially moved. Driven outward. Due to the axial driving force of the outer end of the motor plunger 25 outward in the axial direction, the motor plunger 25 moves outward and along the inclined surface formed by the motor swing member 21 and the bearings B7 and B8. It moves with the motor swash plate 22. As a result, the motor cylinder 23 rotates as the motor plunger 25 moves. As the motor cylinder 23 rotates, the valve body 33 integrated therewith also rotates, and the motor side eccentric cam ring 52 reciprocates the motor side switching valve 48 in the radial direction of the valve body 33.

  Since the motor cylinder 23 rotates with the rotation of the motor swash plate 22 around the output shaft 6, the motor plunger 25 on the opposite side of the motor plunger 25 moving outward with respect to the transmission center plane C is The hydraulic oil in the motor oil chamber 26 moves inward with the rotation of the plate 22 and is pushed out from the motor opening passage 27 to the low-pressure oil passage 60 and passes through the pump side communication passage 49 and the pump opening passage 16 (FIG. 2). Absorbed in the pump oil chamber 15.

  As described above, the hydraulic closed circuit that connects the hydraulic pump 2 and the hydraulic motor 3 is configured by the distribution valve 4, and hydraulic oil discharged according to the rotation of the hydraulic pump 2 is supplied to one side of the hydraulic closed circuit (the high pressure oil path). 61), the hydraulic oil 3 is sent to the hydraulic motor 3 through the rotation of the hydraulic motor 3, and the hydraulic oil discharged from the hydraulic motor 3 as the hydraulic motor 3 rotates passes through the other side of the hydraulic closed circuit (low pressure oil passage 60). To the hydraulic pump 2.

  In the above-described hydrostatic continuously variable transmission 1, the hydraulic pump 2 is driven by the input from the internal combustion engine, and the rotational driving force of the hydraulic motor 3 is shifted via the distribution valve 4 and the hydraulic motor 3. Taken out and transmitted to the wheel. When the vehicle is traveling normally, the high pressure oil passage 61 becomes high pressure and the low pressure oil passage 60 becomes low pressure. However, when traveling downhill or the like, when the driving force from the wheels is transmitted from the output shaft 6 to the hydraulic motor 3 and the rotational driving force of the hydraulic pump 2 is transmitted to the internal combustion engine and the engine braking action occurs, the low pressure oil The passage 60 becomes high pressure, and the high pressure oil passage 61 becomes low pressure.

  FIG. 7 is a cross-sectional view of the motor servo mechanism 28 that changes the angle of the motor swing member 21. The motor servo mechanism 28 includes a ball screw shaft 30 that is positioned near the arm portion 21 a of the motor swing member 21 and is parallel to the output shaft 6, and a ball nut 29 that is screwed to the ball screw shaft 30. The ball nut 29 is connected to the arm portion 21a of the motor swing member 21, and when the ball screw shaft 30 is driven to rotate, the ball nut 29 moves on the ball screw shaft 30 and the motor swing member 21 rotates. .

  In order to rotationally drive the ball screw shaft 30, a swash plate control motor 62 is attached to the outer surface of the transmission housing 7. The driving force of the pinion 63a provided on the rotating shaft 63 of the swash plate control motor 62 is transmitted to the gear 65 at the end of the ball screw shaft 30 via the intermediate gears 64a and 46b of the intermediate shaft 64, and rotates the ball screw shaft 30. It is possible to drive and rotate the motor swing member 21 to change the inclination angle of the motor swash plate 22.

  FIG. 8 is a cross-sectional view showing a state in which the motor swinging member 21 is upright by the motor servo mechanism 28 (the rotation surface of the swash plate is orthogonal to the output shaft 6). The gear ratio of the hydrostatic continuously variable transmission 1 can be changed steplessly by changing the inclination angle of the motor swing member 21. When the inclination angle of the motor swinging member 21 is changed and the motor swash plate 22 is orthogonal to the output shaft 6, the top gear ratio is obtained.

  FIG. 9 is a cross-sectional view of the vicinity of the motor eccentric annular member 55 and the motor side eccentric cam ring 52 when the amount of eccentricity becomes zero. When the inclination of the motor swash plate 22 reaches 90 degrees, that is, the top gear ratio, hydraulic oil is injected into the actuator 66, the piston rod 67 is pushed out, the motor eccentric annular member 55 is driven to rotate, and the motor side eccentric cam ring Control is performed so that the amount of eccentricity of 52 becomes zero. At this time, the center B of the motor side eccentric cam ring 52 coincides with the center A of the valve body 33. FIG. 9 shows a state where the center A and the center B coincide with each other in this way. At this time, the hydraulic closed circuit including the hydraulic pump 2, the high pressure oil passage 61, the hydraulic motor 3, and the low pressure oil passage 60 is closed, and the pump cylinder 10, the valve body 33, the motor cylinder 23, and the output shaft 6 are connected to the transmission. The input gear 14 and the pump casing 8 are integrally rotated (so-called direct connection), and the input rotation and the output rotation are the same. This state is called lockup. An appropriate amount of hydraulic oil adjusted in advance by the actuator control mechanism is injected into the actuator 66 for lockup.

  FIG. 10 is a view showing a state in which hydraulic oil is further injected into the actuator 66, the piston rod 67 is further pushed out, and the motor eccentric annular member 55 is driven to rotate rightward in the drawing for backward drive of the vehicle. It is. At this time, the center B of the motor-side eccentric cam ring 52 is located on the right side of the transmission center plane C toward the motor cylinder 23 and on the right side of the center A of the valve body 33. This is a state operated when moving from the stop state of the vehicle to the reverse direction, and the angle of the swash plate is the same as the angle at the time of normal forward movement. When the internal combustion engine is started, the high pressure oil supply position in the valve body 33 is directed toward the motor cylinder, and the left side of the transmission center plane C, that is, the transmission center plane, is opposite to that during forward travel. The output rotator R rotates in the opposite direction to the forward direction, the output shaft 6 reverses, and the vehicle can be moved backward.

  By injecting the maximum amount of hydraulic oil into the actuator 66, the eccentric cam ring 52 is further eccentric, and in the opposite direction to that during normal operation, the rotation of the output shaft 6 is reversed to the input rotation direction. Therefore, a mechanism for rotating the output shaft 6 in the reverse direction can be configured with a simple configuration.

  The output shaft reverse rotation mechanism is provided with the eccentric cam ring 52 so as to be rotatable about a pin 56 provided above the eccentric cam ring 52, and with respect to the center B of the eccentric cam ring 52 of the eccentric cam ring 52. Since the opposite side of the pin 56 is driven by the actuator 66, the output shaft reverse rotation mechanism can be configured with a simple configuration. In addition, since the actuator 66 includes an actuator control device capable of two-stage control, a hydraulic actuator can easily realize two-stage operations of lockup and output shaft reverse rotation.

  If the internal combustion engine is already in operation when the vehicle is to be moved backward, the motor eccentric ring is set with the clutch (not shown) provided between the internal combustion engine and the continuously variable transmission 1 turned off. The member 55 is rotated, and after the rotation of the motor eccentric annular member 55 is completed, the clutch is turned on, and the driving force of the internal combustion engine is connected to the continuously variable transmission input gear 14.

  The actuator control device is provided with means for prohibiting the operation of the actuator for switching to the reverse rotation of the output shaft when the cylinder is rotating, so there is no sudden reverse rotation during normal rotation, It is safe. Further, when the speed ratio is less than a predetermined value before the output shaft 6 is reversely rotated, the means for changing the inclination angle of the swash plate 22 to change the speed ratio to a predetermined value or more, or the reverse rotation of the output shaft 6 Since the means for prohibiting the operation of the hydraulic actuator 66 for switching is provided, it is possible to prevent engine stop at the time of reverse rotation of the output shaft. Since the hydrostatic continuously variable transmission 1 includes the centrifugal governor clutch 5, the hydrostatic continuously variable transmission 1 starts operating smoothly after the driving force of the internal combustion engine is input.

  FIG. 11 is a longitudinal sectional view of the vicinity of the centrifugal governor clutch 5. In the hydrostatic continuously variable transmission 1, when the low pressure oil passage 60 and the high pressure oil passage 61 are connected, high oil pressure is not generated, and power transmission between the hydraulic pump 2 and the hydraulic motor 3 is not performed. . That is, clutch control is performed by controlling the communication opening degree between the low pressure oil passage 60 and the high pressure oil passage 61.

  The centrifugal governor clutch 5 includes a cam plate 70 and a spring seat 71 coupled to the end of the pump casing 8 by bolts 69, and a plurality of cam plate grooves formed on the inner surface of the cam plate 70 so as to extend obliquely in the radial direction. A roller 72 respectively received in 70a, a pressure receiving plate 73 having an arm portion 73a facing the cam plate groove 70a, a coil spring 74 supported at one end by a spring seat 71 and energizing the pressure receiving plate 73 at the other end A sliding shaft 75 that is integrally connected to the central portion of the pressure receiving plate 73 and that is inserted into the central through hole 70b of the cam plate 70 and slides in the axial direction, and a clutch valve mechanism of the sliding shaft 75. It is composed of a rod-like clutch valve 76 locked to the stop portion 75a. The clutch valve 76 is inserted into a clutch valve hole 77 provided in the output shaft 6. The pressure receiving plate 73 and the sliding shaft 75 are integrally coupled by welding.

  When the pump casing 8 is stationary, that is, when neither the cam plate 70 nor the spring seat 71 is rotating, the arm portion 73a presses the roller 72 against the cam plate groove 70a by the biasing force applied by the coil spring 74 to the pressure receiving plate 73. Since the cam plate groove 70a is inclined, the roller 72 is pushed inward in the radial direction of the cam plate 70, and is locked to the pressure receiving plate 73, the sliding shaft 75 integral therewith, and the sliding shaft 75. The clutch valve 76 is moved to the left.

  When the pump casing 8 is rotationally driven via the transmission input gear 14 (FIG. 1) and the cam plate 70 and the spring seat 71 are rotated, the roller 72 is radially outward along the inclined surface of the cam plate 70 by centrifugal force. The arm portion 73a is pushed rightward, and the pressure receiving plate 73 moves rightward against the urging force of the coil spring 74. Since the arm portion 73a is engaged with an engagement plate 71a provided on the spring seat 71, the pressure receiving plate 73 rotates integrally with the spring seat 71. The amount of movement of the pressure receiving plate 73 and the sliding shaft 75 integral therewith in the right direction is determined according to the centrifugal force acting on the roller 72, that is, the rotational speed of the pump casing 8. When the rotational speed of the pump casing 8 increases, the clutch valve 76 locked to the sliding shaft 75 moves to the inner part of the clutch valve hole 77 in the output shaft 6. In this way, the centrifugal governor mechanism is configured using the centrifugal force acting on the roller 72 by the rotation of the pump casing 8.

  As shown in FIG. 11, the output shaft 6 is formed with a low pressure oil passage communication passage 79 that connects the low pressure oil passage 60 and the clutch valve hole 77, and the output shaft 6 and the pump cylinder 10 have a high pressure oil passage 61. The slanted oil passage 80, the annular groove 81, and the high-pressure oil passage communication passage 82 that connect the clutch valve hole 77 to each other are formed. When the pump casing 8 is stationary, the low pressure oil passage communication passage 79 and the high pressure oil passage communication passage 82 communicate with each other via the small diameter portion 76a of the clutch valve 76. As a result, the low pressure oil passage 60 and the high pressure oil passage 61 are communicated. Is in communication, the clutch is OFF.

  When the rotation of the pump casing 8 exceeds a predetermined speed and the clutch valve 76 moves to the innermost part of the clutch valve hole 77 by the centrifugal force action of the governor mechanism, the opening of the high-pressure oil passage connecting passage 82 is larger than the clutch valve 76. It is blocked by the radial side surface 76b (see the position of the clutch valve 76 in FIG. 2). As a result, the communication between the low-pressure oil passage 60 and the high-pressure oil passage 61 is cut off, and a closed circuit of the oil circulation composed of the hydraulic pump 2, the high-pressure oil passage 61, the hydraulic motor 3, and the low-pressure oil passage 60 is formed. The continuously variable transmission 1 functions. Since the transition from the clutch OFF state to the clutch ON state is due to the movement of the roller 72, the clutch is gradually connected accordingly.

  FIG. 12 is a longitudinal sectional view of a main part of the hydrostatic continuously variable transmission 1 showing a supply path for hydraulic oil and lubricating oil. The hydraulic oil is supplied from a high-pressure oil pump (not shown) provided in the internal combustion engine to an output shaft central oil passage 85 formed in the axial direction at the center of the output shaft 6 from the right end of the figure. The output shaft center oil passage 85 is connected to an oil passage 86 extending in the radial direction and reaching the outer periphery at the innermost portion. The oil passage 86 is further formed in an output rotating body oil passage 87 formed in parallel with the output shaft 6 in the output rotating body R (motor cylinder 23, valve body 33, pump cylinder 10) that rotates integrally with the output shaft 6. Connect with. The output rotating body oil passage 87 is an oil passage comprising an oil passage 87 a in the motor cylinder 23, an oil passage 87 b in the valve body 33, and an oil passage 87 c in the pump cylinder 10.

  A check valve 88 for supplying supplementary oil into the high-pressure oil passage 61 is provided in the pump cylinder 10. The output rotating body oil passage 87 is connected to a check valve 88 via an oil passage 89 that extends radially outward at the innermost portion thereof, and according to leakage of hydraulic oil (pressure drop) from the high-pressure oil passage 61, The hydraulic oil is supplied to the high pressure oil passage 61 of the valve body 33. Another part of the pump cylinder 10 is provided with an oil passage for replenishing hydraulic oil to the low-pressure oil passage 60 and a check valve in the same manner as described above, and according to leakage of hydraulic oil from the low-pressure oil passage 60 (pressure drop). The hydraulic oil is supplied to the low pressure oil passage 60 (not shown).

  An outer peripheral annular groove 90 is provided on the outer periphery of the output shaft 6 corresponding to the innermost part of the output rotating body oil passage 87 and communicates with the innermost part of the output rotating body oil passage 87. An inner peripheral annular groove 91 is provided on the inner periphery of the clutch valve hole 77 of the output shaft 6, and communicates with the outer peripheral annular groove 90 through one communicating oil passage 92. Lubricating oil injection nozzles 93 that communicate with the clutch valve hole inner peripheral annular groove 91 toward the outer periphery of the output shaft 6 are formed in the output shaft 6 around the output shaft. Part of the oil supplied into the output rotating body oil passage 87 is injected through the outer peripheral annular groove 90, the communication oil passage 92, the inner peripheral annular groove 91, and the lubricating oil injection nozzle 93, and the pump swash plate 9 and the like are injected. Lubricated.

  The output shaft 6 is provided with one radial oil passage 94 from the output shaft central oil passage 85 toward the retainer ring 39 of the right end positioning portion of the output rotating body R. The outer end of the radial oil passage 94 communicates with an annular groove 39b formed on the inner periphery of the retainer ring 39. A part of the oil supplied into the output shaft center oil passage 85 is supplied to the lubricating oil injection nozzle 39a (FIG. 4) which is formed in the retainer ring 39 in communication with the inner peripheral annular groove 39b. Sprayed from the lubricant spray nozzle 39a, the motor swash plate 22 and the like are lubricated.

As described in detail above, the following effects are brought about in the above embodiment.
(1) The motor-side eccentric cam ring 52 is further decentered by the actuator 66, and the transmission center plane C is decentered in the direction opposite to that during normal operation, thereby rotating the output shaft 6 in the reverse direction of the input rotation direction. Since it is made to rotate in the direction, a mechanism for reversely rotating the output shaft 6 can be configured with a simple configuration.
(2) In the output shaft reverse rotation mechanism, the motor side eccentric cam ring 52 is provided so as to be rotatable about a rotation center 56 provided outside the eccentric cam ring, and each of the eccentric cam rings Since the opposite side of the rotation center 56 with respect to the center B of the ring is driven by the actuator 66, the output shaft reverse rotation mechanism can be configured with a simple configuration.
(3) Since the actuator includes an actuator control device capable of two-stage control, the hydraulic actuator 66 can easily realize the two-stage operation of lockup and output shaft reverse rotation.
(4) The actuator control device is provided with means for prohibiting the operation of the actuator 66 for switching to the reverse rotation of the output shaft when the cylinders 10 and 23 are rotating. Since it can prevent switching to a shaft reverse rotation, it is safe.
(5) Means for changing the inclination ratio of the swash plate 22 to change the transmission gear ratio to a predetermined value or more when the transmission gear ratio is less than a predetermined value before the output shaft 6 is reversely rotated, or the output shaft 6 reversely rotated Since the means for prohibiting the operation of the hydraulic actuator 66 for switching to is provided, it is possible to prevent the engine from being stopped when the output shaft rotates reversely.

  DESCRIPTION OF SYMBOLS 1 ... Hydrostatic continuously variable transmission, 2 ... Swash plate plunger type hydraulic pump, 3 ... Swash plate plunger type hydraulic motor, 9 ... Pump swash plate, 10 ... Pump cylinder, 12 ... Pump plunger, 22 ... Motor swash plate, 23 ... Motor cylinder, 25 ... Motor plunger, 33 ... Valve body, 47 ... Pump side switching valve, 48 ... Motor side switching valve, 51 ... Pump side eccentric cam ring, 52 ... Motor side eccentric cam ring, 56 ... Pin, 60 ... Low pressure 61, high pressure oil path, 66, actuator, A, rotation center of the valve body 33, B, center of the motor-side eccentric cam ring 52, C, transmission center plane, O, rotation center of the motor swing member, R ... Output rotating body

Claims (5)

Between two swash plates (9, 22), a hydraulic pump (2) comprising a plurality of plungers (12) provided on a cylinder (10) and a plurality of plungers (25) provided on another cylinder (23) A hydraulic motor (3), a high-pressure oil passage (61) for sending hydraulic oil from the hydraulic pump (2) to the hydraulic motor (3) side, and the hydraulic pump (2) from the hydraulic motor (3) side Low pressure oil passage (60) for feeding hydraulic oil to the side, and a reciprocating motion in the radial direction of the valve body (33) in contact with the inner peripheral surface of the eccentric cam ring (51, 52), and the plunger (12, 25) A hydraulic circuit including a hydraulic switching valve (47, 48) for switching the correspondence relationship between the high pressure oil passage (61) or the low pressure oil passage (60), a plunger (12) of the hydraulic pump (2), and the hydraulic motor (3) provided between the plunger (25) and tilting at least one (22) of the swash plate (9, 22) to change the gear ratio, and the eccentric cam ring (52) to the actuator ( 66) In a hydrostatic continuously variable transmission (1) equipped with a lock-up mechanism that is eccentrically closed according to 66)
By further driving the eccentric cam ring (52) by the actuator (66) and decentering it in the direction opposite to that during normal operation, the rotation of the output shaft (6) is rotated in the direction opposite to the input rotation direction. A hydrostatic continuously variable transmission (1).   The output shaft reverse rotation mechanism is provided with the eccentric cam ring (52) rotatably about a rotation center (56) provided outside the eccentric cam ring (52), and the eccentric cam ring (52 2), the opposite side of the center of rotation (56) with respect to the center (B) of the eccentric cam ring is driven by the actuator (66). transmission.   The hydrostatic continuously variable transmission according to claim 1 or 2, wherein the actuator (66) is a hydraulic actuator (66) provided with an actuator controller capable of two-stage control.   The actuator control device is provided with means for inhibiting the operation of the actuator (66) for switching to the reverse rotation of the output shaft (6) when the cylinder (10, 23) is rotating. The hydrostatic continuously variable transmission according to any one of claims 1 to 3.   Means for changing the inclination ratio of the swash plate (9, 22) to change the transmission ratio to a predetermined value or more by changing the inclination angle of the swash plate (9, 22) when the transmission ratio is less than a predetermined value before the output shaft (6) is rotated in reverse (6) The hydrostatic continuously variable transmission according to any one of claims 1 to 4, further comprising means for prohibiting the operation of the hydraulic actuator (66) for switching to reverse rotation. Machine.

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