JPH0689832B2 - Hydraulic continuously variable transmission - Google Patents

Description

Detailed Description of the Invention a. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic continuously variable transmission including a hydraulic pump and a hydraulic motor.

(Prior Art) Various types of hydraulic continuously variable transmissions in which at least one of them has a variable displacement and a hydraulic pump and a hydraulic motor are combined have been known and put into practical use. .

For example, as disclosed in JP-B-32-7159 and JP-A-62-224769, a hydraulic continuously variable transmission combining a fixed displacement swash plate axial pump and a variable displacement swash plate axial motor. There is. In this transmission, the pump swash plate and the motor cylinder are integrally connected, and when the motor swash plate is perpendicular to the shaft and the motor capacity becomes zero, the pump and the motor are directly connected and integrally rotated, That is, a transmission of the Hiddle Mechanical (HMT) type is configured.

Not only those using such axial pumps and motors, but also many using radial pumps and motors are known. For example, there is one disclosed in Japanese Examined Patent Publication (Kokoku) No. 45-39365, and the hydraulic unit disclosed in this publication uses a ball as a plunger, and this ball is radially moved in the cylinder by an eccentric cam member arranged on the outer peripheral side. It is configured to reciprocate to perform a pump or motor action.

(Problems to be Solved by the Invention) In such a hydraulic continuously variable transmission, its configuration is required to be as simple and compact as possible. However, when such a hydraulic continuously variable transmission is used in an automobile or the like, it is possible and easy to perform variable control of the pump and motor capacities, and it is possible to adequately meet various traveling demands. Is desirable.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a hydraulic continuously variable transmission that has a simple and compact structure and is capable of supporting various controls.

B. Structure of the Invention (Means for Solving the Problems) As means for achieving the above object, in the present invention,
A pump cylinder casing, a pump shaft rotatable with respect to this pump cylinder casing, a pump cam member that rotates integrally with this pump shaft, and slidably inserted into a plurality of cylinder holes formed in the pump cylinder casing. A hydraulic pump having a plurality of pump plungers, which is configured to reciprocate the pump plunger in a cylinder hole by a pump cam member that is integrally rotated with a pump shaft to suck and discharge oil.
Motor cylinder casing, motor shaft rotatable with respect to this motor cylinder casing, motor cam member rotating integrally with this motor shaft, and slidably inserted into a plurality of cylinder holes formed in the motor cylinder casing. And a plurality of motor plungers that are driven, the motor plunger reciprocates in the cylinder hole by the oil discharged from the hydraulic pump, and this reciprocating motion is transmitted to the motor shaft via the motor cam member and rotationally driven. And a transmission housing that fixedly supports the motor cylinder casing and rotatably supports the pump cylinder casing constitute a hydraulic continuously variable transmission, and the pump cylinder casing and the motor. It is connected to the shaft.

In this case, the hydraulic pump and the hydraulic motor may be a radial type unit in which the pump cylinder and the motor cylinder extend substantially in the radial direction, or the pump cylinder and the motor cylinder may move in the substantially axial direction. It may be an axial type unit that is extended.

(Operation) In the case of the hydraulic continuously variable transmission configured as described above, the pump cam member reciprocates the pump plunger in the cylinder hole to suck and discharge oil. The stroke of the reciprocating motion at this time To control the variable hydraulic pump. Similarly, in the hydraulic motor, the reciprocating stroke when the motor plunger reciprocates in the cylinder hole is variably controlled by the oil discharged from the hydraulic pump. It becomes a motor. Therefore, by providing at least one of the pump and the motor with variable displacement control, it is possible to obtain a hydraulic continuously variable transmission that can continuously control the speed ratio.

If the capacity of the hydraulic motor is variably controlled to zero, the hydraulic pressure is locked and the pump cylinder casing and the motor shaft are connected, so the pump shaft and motor shaft are directly connected and the gear ratio is 1.0. It becomes a state.

In the above case, an eccentric cam is used as a cam member in the case of a radial pump or a motor, and variable displacement control is possible by adjusting the eccentric amount of this eccentric cam.
In the case of an axial type pump or motor, a swash plate is used as a cam member, and variable displacement control is possible by adjusting the inclination angle of this swash plate.

(Examples) Hereinafter, preferred examples of the present invention will be described with reference to the drawings.

FIG. 1 shows a hydraulic continuously variable transmission CVT according to the present invention. This hydraulic continuously variable transmission CVT is composed of a radial hydraulic pump P and a radial hydraulic motor M arranged in the transmission housing 1. Both the hydraulic pump P and the hydraulic motor M are capable of variably controlling their displacements, and either or both of the displacements are variably controlled to continuously change the rotation of the pump main shaft (transmission input shaft) 12. It is transmitted to the motor main shaft (transmission output shaft) 51.

The transmission housing 1 is divided into three parts, and the hydraulic pump P is disposed in the first space 8a surrounded by the first housing 1a and the second housing 1b, and the second housing 1b and the third housing 1c are provided. A hydraulic motor M is arranged in a second space 8b surrounded by.

First, the hydraulic pump P will be described with reference to FIG. 2 showing a cross section along the arrow II-II.

The hydraulic pump P has a pump casing 11 rotatably supported by the transmission housing 1 via ball bearings 31a and 31b. This casing 11 is configured by tightening a plurality of bolts 35 into left and right casings 11a and 11b divided into two parts.

The pump main shaft 12 projects outward to enable driving from the outside, and its inner end surface has a crankpin 14 having an axis C ₂ eccentric from the axis C ₁ of the main shaft 12 by a distance L _1. Is formed integrally with the main shaft 12. The tip of the crank pin 14 is fitted and coupled to the shaft support member 13. The pump main shaft 12, the crank pin 14, and the shaft support member 13 are integrally supported rotatably by the pump casing 11 via ball bearings 32a and 32b, and the rotation axis thereof is the axis C ₁ . Therefore, the shaft center C ₂ of the crankpin 14 revolves around the shaft center C ₁ . A needle bearing 34, which will be described later, is provided between the main shaft 12 and the bearing 32a.
And a rotating sleeve 16 is provided.

An eccentric collar 15 having an axis C ₃ which is eccentric from the crankpin axis C ₂ by a distance L ₂ is rotatably attached to the crankpin 14. An internal gear 15a is formed on the right side of the eccentric collar 15, and the internal gear 15a is a rotating sleeve.
It meshes with 16 external gears 16a.

The rotating sleeve 16 is rotatable with respect to the main shaft 12 by a needle bearing 34. However, a sliding sleeve 17 having an inner tooth spline 17b that meshes with the outer tooth spline 12a of the shaft 12 is attached to the main shaft 12 so as to be slidable in the axial direction. The outer tooth spline 17a meshes with the inner tooth spline 16b of the rotating sleeve 16. For this reason,
The main shaft 12, the sliding sleeve 17, the rotating sleeve 16 and the eccentric collar 15 rotate integrally. In this case, the axis C ₃ of the eccentric collar 15 makes an orbital motion about the axis C ₁ of the main shaft 12.

As can be seen from such a configuration, by the internal gear 15a of the eccentric collar 15, the rotating sleeve 16 and the sliding sleeve 17,
A restraint means for restraining the rotation of the eccentric collar 15 is configured, and the restraint means and the eccentric collar 15 constitute a pump cam member in the claims.

Here, the internal spline 17b of the sliding sleeve 17 and the external spline 12a of the main shaft 12 are straight splines, and the external spline 17a of the sliding sleeve 17 and the internal spline 16b of the rotating sleeve 16 are helical splines. is there. Therefore, when the sliding sleeve 17 is slid in the axial direction, the rotating sleeve 16 is rotated by the helical spline.
Are rotated relative to the main shaft 12. The rotation of the rotating sleeve 16 is performed by the eccentric collar 15 via the gears 16a and 15a.
And the eccentric collar 15 is rotated about the crank pin 14. As can be seen from this, the above-mentioned restraint means has a position adjusting function for adjusting the rotational position of the eccentric collar 15.

The movement of the shaft center C ₃ when the eccentric collar 15 is rotated is shown in FIG. In this figure, the eccentric collar 15 is rotated 90 ° clockwise with respect to the crank pin 14. Initially, the shaft center C ₁ of the main shaft 12, the shaft center C ₂ of the crank pin 14 and the shaft center C ₃ of the eccentric collar 15 are positioned on the same straight line. When it is rotated 90 degrees around 14, the axis of the eccentric collar 15 becomes
Move to the position indicated by C ₃ ′. Because of this, the main shaft
The distance between the axis C _{1 of} 12 and the axis C ₃ of the eccentric collar 15 (the radius of revolution of the axis C ₃ of the eccentric collar 15 with respect to the axis C ₁ of the main shaft 12) L ₃ is the distance L ₃ ′ (< L ₃ ).

It should be noted that this distance L ₃ is the maximum in the above-mentioned initial state (the state where C ₁ , C ₂ , and C ₃ are aligned on the same straight line), and the distance L ₃ is changed from this state in accordance with the rotation of the eccentric collar 15. Is gradually reduced to a minimum when it is rotated 180 °. In the case of this minimum, the eccentricity L ₁ axis C ₂ relative to the axis C _1, when the eccentricity L ₂ axes C ₃ relative to the axis C ₂ are equal, the distance (radius of revolution) L ₃ is zero and Become.

That is, the eccentric distance (revolution radius) L ₃ of the eccentric collar 15 with respect to the main shaft 12 can be changed by moving the sliding sleeve 17 in the axial direction. The movement of the sliding sleeve 17 is performed by engaging the tip end 18a with the groove 17c of the sliding sleeve 17 and rotating the lever 18 rotatable about the shaft 19.

On the other hand, a coupling ring 20 is attached to the eccentric collar 15 by a needle bearing 33 so as to be relatively rotatable. Therefore, the connecting ring 20 can rotate on the eccentric collar 15 about the axis C ₃ . Further, seven pump cylinders 25 are radially arranged around the connecting ring 20 in a radial direction. Each of these cylinders 25 is swingably attached to the pump casing 11 at a pair of trunnion portions 25b.

The cylinder hole 25a of each cylinder 25 is open to the inner diameter side, and six pump plungers 22 and one pump plunger 23 are slidably inserted from the inner diameter side into each cylinder hole 25a. 6 pump plungers 22
Each of the inner diameter side end portions 22a is rotatably connected to six arm portions 20a formed on the connecting ring 20 by pins 21. The remaining one pump plunger 23 is integrally connected to the connecting ring 20 at its inner diameter side end 23a.

The internal space of the cylinder hole 25a communicates with the oil inflow hole 3b and the oil outflow hole 3c formed in the pump casing 11 through the oil passage holes 25c and 25d formed in the left and right trunnion portions 25b. The oil inflow hole 3b is connected to the oil passage 3a through a check valve 28 that allows only an oil flow in the inflow direction, and the oil passage 3a is formed in the transmission housing 1 via an oil delivery ring 27. It communicates with the oil passages 2a and 2b. The first oil passage 2a communicates with the second space 8b via the strainer 7.

Further, the oil passage 3c is connected to the oil passage 3d through a check valve 29 that allows only the oil flow in the outflow direction, and further, the oil passage 3d
Communicates with the second oil passage 4 formed in the transmission housing via the oil transfer ring 30.

Next, the configuration of the hydraulic motor M will be described with reference to FIG. 1 and FIG. 4 showing a cross section taken along the arrow IV-IV in this figure.

The casing of the motor M is formed by the transmission housing 1, and the motor casing is fixedly held.

The motor main shaft 51 protrudes outward to allow power to be taken out to the outside, and a crankpin having an axis C ₅ eccentric from the axis C ₄ of the main shaft 51 by a distance L _{4 on} its inner end surface. 53 is formed integrally with the main shaft 51. The tip end of the crank pin 53 is fitted and coupled to the shaft support member 52. The motor main shaft 51, crank pin 53, and shaft support member 52 are integrally rotatably supported by the transmission housing (motor casing) 1 via ball bearings 71a and 71b, and the rotation axis thereof is the axis. It is C ₄ . Therefore, the axis C ₅ of the crank pin 53 makes an orbital motion centering on the axis C ₄ .
In addition, between the main shaft 51 and the bearing 71a,
A needle bearing 73 and a rotating sleeve 55 described later are arranged, and a needle bearing 74 and a rotating sleeve 86 described later are arranged between the shaft support member 52 and the bearing 71b.

The crank pin 53, eccentric collar 54 having a shaft center C ₆ which is eccentric from the crank pin axis C ₅ by a distance which L ₅ is mounted rotatably. An internal gear 54a is formed on the left side of the eccentric collar 54, and the internal gear 54a is a rotating sleeve.
It meshes with the external gear 55a of 55.

The rotating sleeve 55 is rotatable with respect to the main shaft 51 by a needle bearing 73. However, a sliding sleeve 56 having an inner tooth spline 56b that meshes with the outer tooth spline 51a of the shaft 51 is axially slidably attached to the main shaft 51. The outer tooth splines 56a mesh with the inner tooth splies 55b of the rotating sleeve 55. Therefore, the main shaft 51, the sliding sleeve 56, the rotating sleeve 55, and the eccentric collar 54 rotate integrally. In this case, the eccentric collar
The axis C _{6 of} 54 performs an orbital motion about the axis C ₄ of the main shaft 51.

Here, the internal tooth spline 56b of the sliding sleeve 56 and the external tooth spline 51a of the main shaft 51 are straight splines, and the external tooth spline 56a of the sliding sleeve 56 and the internal tooth spline 55b of the rotating sleeve 55 are helical splines. is there. Therefore, when the sliding sleeve 56 is slid in the axial direction, the rotating sleeve 55 is relatively rotated with respect to the main shaft 51 by the helical spline. The rotation of the rotating sleeve 55 is transmitted to the eccentric collar 54 via the gears 55a and 54a, and the eccentric collar 54 is rotated about the crank pin 53.

FIG. 5 shows the movement of the shaft center C ₆ when the eccentric collar 54 is rotated. This figure shows a case where the eccentric collar 54 is rotated 90 ° clockwise with respect to the crank pin 53. Initially, the shaft center C ₄ of the main shaft 51, the shaft center C ₅ of the crank pin 53 and the shaft center C ₆ of the eccentric collar 54 are positioned on the same straight line. When it is rotated 90 degrees around 53, the axis of the eccentric collar 54 becomes
Move to the position indicated by C ₆ ′. Because of this, the main shaft
L ₆ (revolution radius for the axis C ₄ of the main shaft 51 of axis C ₆ of the eccentric collar 54) the axis C ₄ and the distance between the axis C ₆ of the eccentric collar 54 of the 51, the distance L ₆ '(< L ₆ ).

Note that this distance L ₆ is the maximum in the above-mentioned initial state (the state where C ₄ , C ₅ , and C ₆ are aligned on the same straight line), as in the case of the hydraulic pump P, and from this state, the eccentric collar 54 It becomes minimum when is rotated 180 °. In the case of this minimum, the eccentricity L ₄ axis C ₅ relative to the axis C _4, if is equal to the eccentricity L ₅ axes C ₆ relative to the axis C ₅ is the distance (radius of revolution) L ₆ is zero and Become.

In this way, by moving the sliding sleeve 56 in the axial direction, the eccentric distance (revolution radius) L ₆ of the eccentric collar 54 with respect to the main shaft 51 can be changed. The movement of the sliding sleeve 56 is performed by engaging the tip 58a with the groove 56c of the sliding sleeve 56 and rotating the lever 58 rotatable about the shaft 59.

On the other hand, an annular guide ring 60 is attached to the eccentric collar 54 by a needle bearing 72 so as to be relatively rotatable. Therefore, the guide ring 60 is rotatable on the eccentric collar 54 about the axis C ₆ . Further, five motor cylinders 62 are radially arranged around the guide ring 60. Each of the cylinders 62 is swingably attached to the transmission housing (motor casing) 1 at a pair of trunnion portions 62b.

The cylinder hole 62a of each cylinder 62 is open to the inner diameter side, and five motor plungers 61 are slidably inserted from the inner diameter side into each cylinder hole 62a. The inner diameter side end surface 61a of each of the five pump plungers 61 is
It is in contact with the outer peripheral surface 60a of the guide ring 60.

The internal space of the cylinder hole 62a communicates with the third oil passage 5 formed in the transmission housing 1 through the oil passage hole 62c formed in the trunnion portion 62b.

In the hydraulic pump P and the hydraulic motor M configured as described above, the internal spline 11c formed on the pump casing 11b and the external splice 52b formed on the shaft support member 52 integrally connected to the motor main shaft 51.
The pump casing 11 and the motor main shaft 51 are connected to each other to rotate integrally.

Further, in the above configuration, the oil flowing out from the hydraulic pump P to the second oil passage 4 is supplied into the cylinder hole 62a of the hydraulic motor M in the expansion stroke, and the oil is discharged into the cylinder hole 62a of the hydraulic motor M in the contraction stroke. A distribution mechanism 80 is provided on the side of the hydraulic motor M so that the oil therein flows out to the second oil passage 2a connected to the suction side of the hydraulic pump P.

The distribution mechanism 80 will be described with reference to FIG. 1 and FIG. 6 showing a cross section taken along arrows VI-VI.

The distribution mechanism 80 has a fixed body 81 fixed to the inner wall of the transmission housing 1, and a spool inserted in the fixed body 81 in a radial direction corresponding to each cylinder 62 of the hydraulic motor M. Holes 81d are formed at five places. A distribution spool 82 is slidably inserted in each spool insertion hole 81d, and the outer end of each spool 82 has an outer circumference holding ring 84.
, And the inner end is in contact with the outer peripheral surface 85a of the ball bearing 85 attached to the rotating sleeve 86.

The rotating sleeve 86 is rotatably supported on the transmission housing 1 by a ball bearing 71b, and is rotatable about the axis C ₄ of the motor main shaft 51. However, the ball bearing 85 is eccentrically rotated so as to rotate about an axis C ₇ which is eccentric from the axis C ₄ , and the rotating sleeve.
It is attached to 86. Therefore, when the rotating sleeve 86 is rotated about the axis C ₄ , the axis C ₇ revolves around the axis C ₄ , and the ball bearing 85 is rotated by the axis C _7.
The spool 82 makes an eccentric movement in accordance with the revolution movement of the spool, and the spool 82 makes a reciprocating movement in the insertion hole 81d for a distance corresponding to the amount of eccentricity of the shaft center C ₇ .

Further, the inner tooth spline 86a of the rotating sleeve 86 meshes with the outer tooth spline 87a of the sliding sleeve 87, and the sliding sleeve 87a
The internal tooth splines 87b mesh with the external tooth splines 52a of the shaft support member 52, and the rotating sleeve 86 and the sliding sleeve 87 rotate integrally with the motor main shaft 51.

The sliding sleeve 87 is slidable in the axial direction, and the front end 88a is engaged with the groove 87c, and is slid to the left and right by rotating the lever 88 rotatable about the shaft 89. The internal spline 86a and the external spline 87a are helical splines, the internal spline 87b and the external spline 52a are straight splies, and if the sliding sleeve 87 is slid by the rotation of the lever 88, the helical spline By this action, the rotating sleeve 86 is rotated around the axis C ₄ .

The fixed body 81 has a first communication hole 81 communicating with the second oil passage 4.
a, a second communication hole 81b communicating with the third oil passage 5, and a first oil passage
A third communication hole 81c that communicates with the annular groove 6 that communicates with 2a is formed in communication with the spool insertion hole 81d. Further, the spool 82 is formed with a spool groove 82a as shown in the drawing, and according to the reciprocating movement of the spool 82 in the spool insertion hole 81d, the spool groove 82d allows the first communication hole 81a to be formed.
And the second communication hole 81b communicate with each other, or the second communication hole 81b and the third communication hole 81b
The communication holes 81c are communicated with each other. Specifically, when the distribution spool 82 is moved outward by the revolving motion of the ball bearing 85 described above, the second communication hole is formed.
81b and the 3rd communicating hole 81c are connected, and when the distribution spool 82 is moved inward, the 1st communicating hole 81a and the 2nd communicating hole 81b are connected.

The operation of the hydraulic continuously variable transmission CVT configured as above will be described.

The transmission CVT is driven by rotating the pump main shaft (transmission input shaft) 12. When the pump main shaft 12 is driven to rotate, this shaft 12
The eccentric collar 15 rotates integrally with the eccentric collar 15, and the coupling ring 20 rotatably attached to the eccentric collar 15 has the axial center of the eccentric collar 15 centered on the axial center C ₁ of the pump main shaft 12.
Performs the same orbital movement as that of C ₃ . Therefore, the pump plungers 22 and 23 connected to the connecting ring 20 reciprocate in the cylinder hole 25a of the pump cylinder 25.

Here, the pump plunger 23 is integrally connected to the connecting ring 20, but this is similar to the other plunger 22 in that the pin 21
When it is rotatably connected by means of, the connecting ring 20 freely rotates relative to the pump casing 11 as shown in FIG. Therefore, the connecting ring 20 also rotates in the A direction in response to the rotation of the main shaft 12 in the A direction,
As illustrated, there is a problem that the outer surface of the cylinder 25 comes into contact with the flange 11d for the bolt 35 of the casing 11b, and a problem that the plunger 22 comes out of the cylinder 25 when the flange 11d is sufficiently separated. The reliable reciprocating motion of the plunger 22 cannot be obtained. For this reason, in this example, one plunger 23 is integrally coupled to the coupling ring 20 to prevent relative rotation displacement of the coupling ring 20 with respect to the casing 11 beyond a predetermined value. As a result, the pump plungers 22 and 23 smoothly reciprocate within the cylinder hole 25a of the pump cylinder 25 as the connecting ring 20 revolves.

When the plungers 22 and 23 reciprocate in this way, the check valves 28 and 29 act so that the first oil passages 2a and 2b, the oil inflow holes 3a and 3b and Oil is sucked through the oil passage hole 25c, and the oil passage hole 25d and the oil outflow hole 3c come from the cylinder chamber in the contraction stroke.
The oil is discharged to the second oil passage 4 through. In this case, since each of the plungers 22 and 23 is connected to the connecting ring 20, transmission of force and motion in both directions of pushing and pulling the plungers 22 and 23 from the connecting ring 20 to the plungers 22 and 23. It is possible. Therefore, it is possible to cause the oil to be sucked into the cylinder chamber in the expansion stroke without a problem even if the charge pump does not pressurize the suction side.

The oil discharged to the second oil passage 4 is supplied by the distribution mechanism 80 into the motor cylinder hole 62a on the expansion stroke side, and moves the motor plunger 61 in this cylinder hole 62a in the expansion direction. In accordance with the movement of the motor plunger 61 in the expansion direction, the guide ring 60 with which the inner diameter side end surface 61a of the motor plunger 61 contacts is pressed, and the eccentric collar 54 is rotationally driven. Since the eccentric collar 54 rotates integrally with the motor main shaft 51 as described above, the motor main shaft 51 is also rotationally driven. In addition, as the eccentric collar 54 rotates, the motor plunger 61 on the contraction side contracts,
The oil in the cylinder hole 62a in which the plunger 61 is inserted is discharged to the groove 6 via the distribution mechanism 80 and supplied to the first oil passages 2a and 2b communicating with the groove 6.

When the pump main shaft 12 is driven in this way, the oil discharged from the hydraulic pump P is supplied to the hydraulic motor M, which drives the hydraulic motor M. The oil that has driven the hydraulic motor M is discharged to the groove 6 and is again sucked into the hydraulic pump P via the first oil passages 2a and 2b. The oil in the space 8b is sucked and supplemented.

In the above drive, the amount of oil discharged from the hydraulic pump P corresponds to the relative rotational speed between the pump main shaft 12 and the pump casing 11. The pump casing 11 is rotatably supported and connected to the motor main shaft 51. Therefore, if the displacement of the hydraulic pump P is constant, the pump main shaft 12 and the motor main shaft 51
Proportional to the difference in the number of revolutions with.

Here, the capacity of the hydraulic pump P (the amount of discharged oil per one rotation) is proportional to the reciprocating stroke of the pump plunger 22. This reciprocating stroke can be variably controlled by rotating the lever 18 and adjusting the eccentric distance L ₃ of the eccentric collar 15. In this case, as shown in FIG.
12 axes C ₁ , crankpin 14 axes C ₂ and eccentric collar
The eccentric distance L ₃ is the maximum when the shaft center C _{3 of} 15 is located on the same straight line. From this state, the distance L ₃ gradually decreases according to the rotation of the eccentric collar 15, and this is 180 ° Since it becomes the minimum when it moves, the pump capacity can be variably controlled from the maximum to the minimum by the rotation control of the lever 18.

Incidentally, the eccentricity L ₁ axis C ₂ relative to the axis C _1, when the eccentricity L ₂ axes C ₃ relative to the axis C ₂ are equal, the minimum distance value (radius of revolution) L ₃ becomes zero, The minimum value of the pump capacity is zero. That is, even if the pump main shaft 12 rotates, the amount of oil discharged from the pump becomes zero, whereby a neutral state of the transmission can be obtained.

Similarly, the displacement of the hydraulic motor M can be variably controlled from the maximum displacement to the minimum displacement according to the rotation of the lever 58. In this case, the eccentric distance L ₄ of the axis C ₅ of the crank pin 53 with respect to the axis C ₄ of the main shaft 51 and the eccentric distance L ₅ of the axis C ₆ of the eccentric collar 54 with respect to the axis C ₅ of the crank pin , The minimum value of the displacement of the hydraulic motor M becomes zero.

Therefore, by appropriately controlling the amount of rotation of both levers 18 and 58, the ratio of the output rotation speed (rotation of the motor main shaft 51) to the input rotation speed (rotation of the pump main shaft 12) (= input rotation speed / output) The number of revolutions, that is, the gear ratio can theoretically be controlled infinitely from infinity to 1.0. In this case, the gear ratio becomes infinite when the hydraulic motor M has a predetermined displacement and the displacement of the hydraulic pump P is very close to zero. Further, the hydraulic pump P has a predetermined capacity,
When the displacement of the hydraulic motor M is zero, the gear ratio is 1.0 (the pump shaft and the motor shaft are directly connected).

In the distribution mechanism 80, the cylinder hole 62 on the expansion stroke side
Oil from the hydraulic pump P that is sent to the second oil passage 4 is supplied into a, and oil in the cylinder hole 62a on the contraction stroke side is supplied from the groove 6 to the hydraulic pump P through the first oil passages 2a and 2b. In order to return to the suction side, the farthest point direction of the ball bearing 85 that is eccentrically mounted (the direction of arrow R in FIG. 6 and the direction that pushes the spool 82 outward) is the farthest point direction of the eccentric collar 54 ( This is the direction indicated by the arrow P and is a position perpendicular to the direction in which the motor plunger 61 is positioned at the top dead center).

In this case, the lever 58 for changing the discharge amount of the hydraulic motor M is rotated to move the eccentric collar 54 to the crank pin.
When rotated around 53, the direction of the farthest point of the eccentric collar 54 also changes. For example, as described in Figure 5, when the eccentric collar 54 around the 90 ° rotation of the crank pin 53, the center of the eccentric collar 54 is moved from C ₆ to C ₆ ', the farthest point the direction arrow P Move 45 ° from direction Q. Therefore, in this case, in the distribution mechanism 80, it is necessary to move the ball bearing 85 eccentrically attached to the rotating sleeve 86 in the farthest point direction (the direction in which the spool 82 is pushed to the outermost side) by 45 °. The movement is performed by turning the lever 88.

Further, when the position of the eccentric shaft center C ₇ of the ball bearing 85 is set to a position opposite to the above case (position rotated by 180 °), the inflow of the hydraulic oil from the pump P and the outflow route of the hydraulic oil from the motor M are made. The motor M can be rotated in reverse.

In the above example, for rotating the rotating sleeve 16 for variable displacement control of the hydraulic pump P, rotating the rotating sleeve 55 for variable displacement control of the hydraulic motor M, and controlling the operation of the distribution mechanism 80. The rotation of the rotating sleeve 86 is performed by connecting the inner tooth splines 16b, 55b, 86a of the rotating sleeves 16, 55, 86 and the outer tooth splines 17a, 56a, 87a of the sliding sleeves 17, 56, 87 to the helical splines. This is done by engaging them. However, the present invention is not limited to such an example, the internal tooth splines 16b, 55b, 86a and the external tooth splines 17a, 56a, 87a is a straight spline engagement, instead, a sliding sleeve 17, 56,87 internal tooth splines
17b, 56b, 57b and shaft 12, 51 and shaft support member 52
The external tooth splines 12a, 51a, 52a may be configured to mesh with a helical spline.

Further, both spline meshes may be helical spline meshes. However, in the case of helical spline meshing, there is a problem that a thrust reaction force acts on the meshing member, and it is necessary to have a configuration capable of holding this thrust reaction force. On the other hand, if one side is engaged with the straight spline, there is an advantage that no thrust reaction force is generated at this meshing portion.

In the hydraulic continuously variable transmission described above, the hydraulic pump and the hydraulic motor have different structures. In the hydraulic pump, the coupling ring attached to the cam member is directly coupled to the plunger. The inner end of the plunger contacts the guide ring attached to the member. However, the hydraulic continuously variable transmission according to the present invention is not limited to such a configuration, and a hydraulic motor having the same configuration as the hydraulic pump may be used, or conversely, a hydraulic pump having the same configuration as the hydraulic motor. May be used. However, in the case of the configuration of the hydraulic motor of this example, since the guide ring and the plunger come into contact with each other, the force and the movement in the pulling direction of the plunger cannot be transmitted from the guide ring, and the hydraulic pump of this configuration is When using, a charge pump or the like for pressurizing the suction side is required.

In the above, as a hydraulic pump and a hydraulic motor,
An example using a radial type unit has been shown, but the continuously variable transmission according to the present invention is not limited to this, and an axial type unit may be used.

For example, as shown schematically in FIG. 8, a continuously variable transmission CVT 'may be composed of an axial hydraulic pump P'and an axial hydraulic motor M'.

The hydraulic pump P'is a pump shaft 101, a pump swash plate 102 mounted on the shaft 101 so as to be tiltable and integrally rotatable, and a pump rotatably supported by a transmission housing (not shown). A cylinder 103, a plurality of pump plungers 104 slidably inserted in a plurality of cylinder holes 103a formed in the cylinder 103 so as to extend in the axial direction, and a pump swash plate 102 that rotates integrally with the pump shaft 101. It is composed of a pump actuator 105 that performs tilting control.

The hydraulic motor M ′ has a motor shaft 121 integrally connected to the pump cylinder 103, and a motor swash plate 122 attached to the shaft 121 so as to be tiltable and integrally rotate.
A motor cylinder 123 fixedly supported by a transmission housing (not shown), and a plurality of motor plungers slidably inserted in a plurality of cylinder holes 123a formed in the cylinder 123 extending in the axial direction. 124 and the motor shaft 121
And a pump actuator 125 that integrally rotates to control tilting of the motor swash plate 122.

Between the pump cylinder 103 and the motor cylinder 123, the oil discharged from the pump cylinder chamber is supplied to the motor cylinder chamber on the expansion stroke side, and the oil discharged from the motor cylinder chamber on the contraction side is returned to the suction side of the pump. A distribution mechanism 110 is provided for this purpose.

Here, if the tilt angles of the pump swash plate 102 and the motor swash plate 122 are controlled by the actuators 105 and 125, the capacities of the pump and the motor can be controlled, and continuously variable transmission control can be performed. The operating principle in this case is as shown in FIGS.
The description is omitted because it is the same as the case of the transmission using the radial type unit shown in the figure.

In this example, the actuators 105 and 125 are configured to rotate together with the shafts 101 and 121.However, a sliding slider is provided on each shaft, and tilting control of the swash plates 102 and 122 is performed by the slider slid by the actuator. You can In this way, the actuator can be fixed.

C. As described above, according to the present invention, the hydraulic motor is driven by the discharge oil from the hydraulic pump, the motor cylinder casing is fixedly supported, and the pump cylinder casing is rotatably supported. Moreover, since the hydraulic continuously variable transmission that connects the pump cylinder casing and the motor shaft is configured, not only a hydraulic continuously variable transmission having a compact structure can be obtained, but also the pump and the motor By controlling at least one of the variable displacements, it is possible to obtain a middle-type continuously variable transmission that can control the speed ratio steplessly.

[Brief description of drawings]

FIG. 1 is a sectional view showing a hydraulic continuously variable transmission according to the present invention, and FIG. 2 is an arrow II of a hydraulic pump constituting the continuously variable transmission.
-II is a sectional view taken along line II, FIG. 3 is a schematic view showing the positional relationship of the axial center of each member of the hydraulic pump, and FIG. 4 is an arrow IV of the hydraulic motor constituting the continuously variable transmission.
-IV is a cross-sectional view, FIG. 5 is a schematic view showing the positional relationship of the axial center of each member of the hydraulic motor, and FIG. 6 is a cross-section taken along the arrow VI-VI of the distribution mechanism of the continuously variable transmission. FIG. 7 is a sectional view showing a part of the hydraulic pump taken out, and FIG. 8 is a schematic view showing a different example of the hydraulic continuously variable transmission according to the present invention. 1 …… Transmission housing, 11 …… Pump casing 12 …… Pump main shaft 14 …… Crank pin, 15 …… Eccentric collar 20 …… Coupling ring 22,23 …… Pump plunger 25 …… Pump cylinder 51 …… Motor Main shaft 53 …… Crank pin, 54 …… Eccentric collar 60 …… Guide ring, 61 …… Motor plunger 62 …… Motor cylinder, 82 …… Distribution spool CVT …… Hydraulic continuously variable transmission P …… Hydraulic pump, M ...... Hydraulic motor

Claims (4)

[Claims] 1. A pump cylinder casing, a pump shaft rotatable with respect to the pump cylinder casing, a pump cam member which rotates integrally with the pump shaft, and a plurality of cylinder holes formed in the pump cylinder casing. Each pump plunger is reciprocally moved in the cylinder hole by the pump cam member that is integrally rotated with the pump shaft by a plurality of pump plungers that are slidably inserted. A hydraulic pump that sucks and discharges oil, a motor cylinder casing, a motor shaft that is rotatable with respect to the motor cylinder casing, a motor cam member that rotates integrally with the motor shaft, and the motor cylinder casing. Syrin formed in the And a plurality of motor plungers slidably inserted in the respective hole, and the motor plunger is reciprocated in the cylinder hole by the oil discharged from the hydraulic pump. From a hydraulic motor that transmits to the motor shaft via a member to drive the motor shaft to rotate, and a transmission housing that fixedly supports the motor cylinder casing and rotatably supports the pump cylinder casing. A hydraulic continuously variable transmission, characterized in that the pump cylinder casing and the motor shaft are connected to each other. 2. The hydraulic pump and the hydraulic motor,
2. The hydraulic non-hydraulic unit according to claim 1, wherein the pump cylinder and the motor cylinder are radial type units arranged so as to extend substantially in a radial direction with respect to the pump shaft and the motor shaft, respectively. Gearbox. 3. The hydraulic pump and the hydraulic motor,
2. The hydraulic non-hydraulic unit according to claim 1, wherein the pump cylinder and the motor cylinder are axial type units that are arranged so as to extend substantially axially with respect to the pump shaft and the motor shaft, respectively. Gearbox. 4. The pump shaft, the pump cylinder casing, and the rotation shaft of the motor shaft are arranged on the same axis, as claimed in any one of claims 1 to 3. Hydraulic continuously variable transmission.