JP2782348B2 - Hydrostatic continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Objects of the Invention (1) Industrial Application Field The present invention relates to a hydrostatic stepless motor in which a pump cylinder of a hydraulic pump and a motor cylinder of a hydraulic motor are relatively rotatably abutted. Related to a transmission.

(2) Prior Art Such a continuously variable transmission is already known, for example, as disclosed in Japanese Patent Publication No. 61-23412.

(3) Problems to be Solved by the Invention Conventionally, in such a continuously variable transmission, a mechanism for switching a mode such as a clutch on, a clutch off, and a lock-up is configured in an axial sliding manner. Concentric arrangement to surround the pump cylinder
As a result, there is a problem that the diameter of the transmission cannot be avoided.

The present invention has been made in view of the above circumstances, and even if it is disposed on the same axis as a pump cylinder and a motor cylinder that are relatively rotatably abutted in order to reduce the diameter, clutch-on, clutch-off, lock-up It is an object of the present invention to provide a hydrostatic continuously variable transmission that can easily switch modes such as the above.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a hydrostatic type in which a pump cylinder of a hydraulic pump and a motor cylinder of a hydraulic motor are relatively rotatably arranged. In a continuously variable transmission, a pump cylinder and a motor cylinder are disposed adjacent to each other in the axial direction on a coaxial line, and opposing end surfaces of both cylinders are rotatably contacted with each other. A high-pressure groove and a low-pressure groove that respectively move with the discharge-side group and the suction-side group of the pump port, annular high-pressure oil passages and low-pressure oil passages that communicate with the high-pressure grooves and the low-pressure grooves, respectively, and are concentric with each other; The passages are arranged radially so as to reciprocate so as to communicate with the expansion side group of the pump port of the motor cylinder and the low-pressure oil passage with the contraction side group of the motor port. A number of distribution valves are provided, and an eccentric ring engaged with an outer end of the valve is arranged to surround the motor cylinder so as to drive the distribution valve. A clutch-on position for controlling the stroke of the distribution valve so as to communicate the expansion side group of the port and the low-pressure oil passage with the contraction side group of the motor port, respectively;
Move to a clutch-off position to control the stroke of the distribution valve to release the oil pressure in the high-pressure oil passage to the low-pressure side, and to a lock-up position to control the stroke of the distribution valve to cut off communication between the pump port and the motor port. And a mode switching device capable of causing the mode to be switched.

(2) Operation According to the above configuration, the diameter of the transmission can be reduced by the adjoining and abutting arrangement of the pump cylinder and the motor cylinder in the axial direction. Moreover, between the pump cylinder and the motor cylinder, hydraulic pressure is directly transferred from the pump port to the high-pressure groove and from the low-pressure groove to the pump port. Therefore, an increase in the axial length of the transmission due to the axially adjacent arrangement of the two cylinders can be minimized, and the number of parts can be reduced.

Further, if the eccentric wheel is moved to the clutch-on position, the clutch-off position and the lock-up position by the mode switching device, the transmission is controlled to the clutch-on state, the clutch-off state and the lock-up state by simply changing the stroke of the distribution valve. be able to.

(3) Example Hereinafter, an example of the present invention will be described with reference to the drawings. First, in FIG. 1, U denotes a power unit for a motorcycle, in which an engine E and a hydrostatic stepless converter T of the present invention are accommodated and supported in a casing C. The power of the engine E is transmitted from the crankshaft 1 of the continuously variable transmission T to the input shaft 5 of the continuously variable transmission T through the primary transmission gear train 2, the torque damper 3, and the hydraulic multi-plate clutch 4 in that order.
The power is transmitted to the rear wheels of the motorcycle via the next transmission gear train 7 and a propeller shaft (not shown), and is driven.

The continuously variable transmission T includes a hydraulic pump P and a hydraulic motor M.

The hydraulic pump P includes an input shaft 5, a pump cylinder 9 spline-connected to the input shaft 5, and a large number of annularly arranged cylinder holes 10, 10 provided in the pump cylinder 9 so as to surround the rotation center thereof. Are slidably fitted to each other, and a pump swash plate 12 abutting on the outer ends of the pump plungers 11, 11,.

The hydraulic motor M has a support shaft 14 coaxially fitted to the inner end of the input shaft 5 via a needle bearing 13 so as to be relatively rotatable, and a spline connection 15 to the support shaft 14 so as to be coaxial with the pump cylinder 9. Are slidably fitted to a motor cylinder 16 arranged axially adjacent to each other and a large number of cylinder holes 17, 17,... Of an annular arrangement provided around the rotation center of the motor cylinder 16. , And a motor swash plate 19 that comes into contact with the outer ends of the motor plungers 18, 18,. Motor cylinder
16 is supported at one end of a motor holder 20 for receiving the same via a ball bearing 21, and at the other end of the motor holder 20 is rotatable and axially immovable on a support shaft 14 via a tapered roller bearing 22. It is supported by The motor holder 20 has its outer peripheral surface supported by the casing C so as to be axially movable and non-rotatable.

In the motor holder 20, the motor swash plate 19 is provided with an angular contact ball bearing 25 and a radial needle bearing on a swash plate holder 24 having a trunnion shaft 23.
It is supported rotatably via 26, and the swash plate holder 24 is
The motor holder 20 is supported by a hemispherical inner surface 20a so as to be able to move around the axis 23a of the trunnion shaft 23. A transmission control device (not shown) capable of rotating the trunnion shaft 23 is connected to the trunnion shaft 23, and the operation thereof causes the swash plate holder 24 to be tilted together with the motor swash plate 19 between an upright position and a predetermined maximum tilt position. You.

A flange plate 27 is welded to the motor cylinder 16 at the end on the pump cylinder 9 side, and a hollow output shaft 6 is inserted into the flange plate 27 with a bolt 29 through a pump holder 28 surrounding the pump cylinder 9. Be bound. The pump cylinder 9 is rotatably supported by the inner surface of the pump holder 28 via the needle bearing 30, and the pump swash plate 12 is supported by the inner surface of the output shaft 6 by the angular contact ball bearing 31 and the radial needle bearing 32.
It is supported through.

The centering action of each swash plate 12, 19 is strengthened, and the pump swash plate 12
In order to prevent slippage in the rotational direction between each of the pump plungers 11, 11 ... group, the motor swash plate 19 and the motor plungers 18, 18 ... group, each swash plate 12, 19 has a corresponding plunger 11, 18
Spherical concave portions 12a, 19a are formed, which are joined to the spherical end portions 11a, 18a.

The end of the output shaft 6 is rotatably supported on a partition Ca of the casing C via a ball bearing 33, and the input shaft 5 is rotatable on the output shaft 6 via a ball needle bearing 34 concentric with the bearing 33. It is supported by

The pump cylinder 9 and the motor cylinder 16 abut the opposing end walls 9a, 16a with the resilient force of the spring 35 so as to be relatively rotatable. At the wall end 9a of the pump cylinder 9, pump ports a, a. On the other hand, the end wall 16a of the motor cylinder 16 has an arc-shaped high-pressure groove 3 that matches the discharge side group of the pump ports a, a,.
6h, an arc-shaped low-pressure groove 36l (both shown in FIG. 2) which matches with the suction side group of the pump ports a, a ..., an annular high-pressure oil passage 38h communicating with the high-pressure groove 36h through the through hole 37, The same number of valve holes 39, 39 ... as the cylinder holes 17, 17 ..., penetrating the motor cylinder 16 radially across the high-pressure oil passage 38h,
, And motor ports b, b ... connecting between the valve holes 39, 39 ... and the cylinder holes 17, 17 ... are provided. Further, between the motor cylinder 16 and the support shaft 14, the annular low-pressure oil passage 38l and the high-pressure oil passage 38h, which are open at the respective inner ends of the valve holes 39, 39, communicate with each other through the through hole 40. An annular oil passage 41 is provided. The low-pressure oil passage 38l communicates with the low-pressure groove 36l through the through hole 42.

The low-pressure oil passage 38l communicates with the supply oil passage 45 in the input shaft 5 via the first check valve 43, and the annular oil passage 41 communicates with the supply oil passage 45 via the second check valve 44. . Both the check valves 43 and 44 open when the low-pressure oil passage 38 or the annular oil passage 41 becomes lower in pressure than the supply oil passage 45.

As shown in FIGS. 1 and 3, the valve holes 39, 39 are provided with spool type distribution valves 46, 46, which alternately connect the motor port b to the high and low pressure oil passages 38h, 38l. Cylinder 1
The eccentric ring 47 surrounding the distribution valves 46, 46... Is engaged with the outer ends of the distribution valves 46, 46,. Distributing valve to force its engagement
The outer ends of 46, 46… are mutually concentric with the eccentric ring 47 and the forcing wheel 49
Are linked by

The eccentric 47 is provided on the motor holder 20 with a pivot 50 parallel to the support shaft 14.
And can swing between three positions of a clutch-on position n, a clutch-off position f, and a lock-up position l.

The eccentric 47 is in the clutch-on position n, occupies a position a predetermined distance epsilon ₁ eccentric from the center of the support shaft 14 along the axis 23a of the trunnion shaft 23 (see FIG. 3), also the clutch-off position f in supporting from the center of the shaft 14 occupies a position in which atmospheric consisting distance epsilon ₂ eccentric than the eccentricity epsilon ₁ (see FIG. 4).
Further, the lock-up position 1 occupies a concentric position with the support shaft 14 (see FIG. 5).

The eccentric ring 47 integrally has an ear piece 51 projecting outward on the peripheral wall opposite to the pivot 50, and the eccentric ring 47 is attached to the three positions.
A mode switching device 52 for shifting to n, f, l is connected.

Referring again to FIG. 1, the first and second transmission gear trains 2,
7 are arranged close to each other with the partition Ca interposed therebetween. Thereby, the bending moment applied to the output shafts 5 and 6 from the first and second transmission gear trains 2 and 7 can be minimized.

On the left end wall of the casing C facing the outer end of the input shaft 5, double inner and outer oil guide pipes 53 and 54 are attached via support plates 55 and 56, respectively. Axis 5
Are rotatably and oil-tightly fitted into the left end of the. The inner oil guide pipe 53 communicates with the supply oil passage 45 in the input shaft 5, and the outer oil guide pipe 54 communicates with the hydraulic chamber 4 a of the clutch 4.

The left end wall of the casing C is provided with first and second supply oil passages 58 and 59 for guiding the oil discharged from the supply pump 57 to the inner and outer oil guide pipes 53 and 54, respectively. The passage 59 is provided with a clutch valve 60. This clutch valve 60
When the valve is opened, the pressure oil from the supply pump 57 is supplied to the hydraulic chamber 4a of the clutch 4 to make the clutch 4 connected, and when the valve is closed, the hydraulic chamber 4a is opened to the oil reservoir 61 and the clutch 4 is closed. Can be

 Next, the operation of this embodiment will be described.

The pump cylinder 9 and the motor cylinder 16 are arranged adjacent to each other in the axial direction on a coaxial line, and the opposite end walls 9a, 1
6a are rotatably contacted with each other, so that the diameter of the transmission T can be greatly reduced. In addition, the pump cylinder 9 and the motor cylinder 16 are opposed to their opposed end walls 9a, 9a.
6a, from pump port a to high pressure groove 36h, low pressure groove 36l
Since hydraulic pressure is transferred from the pump port a to the pump port a, there is no need to interpose a dedicated distribution board for such hydraulic pressure transfer between the cylinders 9 and 16, and therefore, the two cylinders 9 and 16 are adjacent to each other in the axial direction. An increase in the axial length of the transmission T due to the arrangement can be minimized, the number of components can be reduced, and the size and structure of the transmission T can be further reduced.

In addition, when the hydraulic pressure is transferred between the two cylinders 9 and 16, the both end walls 9a and 16a are spontaneously formed by the internal hydraulic pressure of the pump cylinder 9 and the motor cylinder 16 due to the generation of the thrust of the pump plunger 11 and the motor plunger 18. As a result, the hydraulic pressure can be effectively prevented from leaking between the two end walls 9a and 16a, and the hydraulic pressure can be efficiently exchanged.

When the eccentric wheel 47 is set to the clutch-on position n as shown in FIG. 3 when the motor cylinder 16 is rotating, each distribution valve 46 causes the eccentric amount ε ₁ in the valve hole 39 according to the eccentric wheel 47.
The motor cylinder 16 reciprocates between a radially inner position and a radially outer position with a stroke twice as long as the stroke. And
In the expansion region Ex of the hydraulic motor M, the distribution valve 46 moves on the inward position side to connect the corresponding motor port b to the high-pressure oil passage 38.
h, and not communicated with the low-pressure oil passage 38l.
h to the cylinder hole 17 of the motor plunger 18 during the expansion stroke
In the contraction region Sh, the distribution valve 46 moves to the outer position side to connect the corresponding motor port b to the low-pressure oil passage 38l and to disconnect from the high-pressure oil passage 38h. , The cylinder hole 17 of the motor plunger 18 during the contraction stroke
Hydraulic fluid is discharged to the low-pressure oil passage 38l from the pump.

Further, the eccentric wheel 47 is moved to the clutch off position f as shown in FIG.
, Each distributing valve 46 has a valve hole according to the eccentric 47.
Twice the eccentric distance epsilon ₂ between the radially inner position and outer position of the motor cylinder 16 reciprocates as a stroke in 39, at its inner and outer positions, the dispensing valve 46 is a high pressure oil passage 38h Is released outside the motor cylinder 16.

Further, the eccentric wheel 47 is moved to the lock-up position l as shown in FIG.
, All the distribution valves 46, 46,... Simultaneously close the corresponding motor ports b, b,.

Thus, when the pump cylinder 16 is rotationally driven from the input shaft 5 while the eccentric wheel 47 is held at the clutch-on position n,
The discharge and suction strokes of the pump plungers 11, 11,... Each pump plunger 11 pumps hydraulic oil in the cylinder hole 17 from the pump port a to the high-pressure groove 36h during the discharge stroke, and transfers hydraulic oil from the low-pressure groove 36l through the pump port a during the suction stroke. Inhalation.

The high-pressure hydraulic oil sent to the high-pressure groove 36h moves to the high-pressure oil passage 38h through the through hole 37, and is supplied by the distribution valve 46 to the cylinder hole 17 of the motor plunger 18 during the expansion stroke through the motor port b. On the other hand, the motor plunger 18 during the contraction stroke
The oil discharged from the cylinder hole 17 is guided from the motor port b to the low-pressure oil passage 38l by the distribution valve 46, and
Through 2 flows into the low pressure groove 36l.

During this time, the output shaft 6 is connected to the pump plunger 11 in the discharge stroke.
The motor cylinder 16 or the output shaft 6 is rotated by the sum of the reaction torque received from the motor cylinder 16 via the pump swash plate 12 and the reaction torque received by the motor cylinder 16 via the motor swash plate 19 from the motor plunger 18 in the expansion stroke. The rotation torque is transmitted to the secondary transmission gear train 7.

The gear ratio of the output shaft 6 to the input shaft 5 is obtained by the following equation.

Therefore, if the capacity of the hydraulic motor M is changed from zero to a certain value, the gear ratio can be changed from one to a certain required value. Moreover, since the capacity of the hydraulic motor M is determined by the stroke of the motor plunger 18, the motor swash plate 19 is tilted from the upright position to a certain tilt position, so that the gear ratio can be steplessly changed from 1 to a certain value. Can be controlled.

During this operation, if the eccentric wheel 47 is shifted to the clutch off position f, the high pressure oil passage 38h is released outside the motor cylinder 16 by the distribution valve 46, so that the high pressure hydraulic oil is supplied to the hydraulic motor M. The power transmission from the hydraulic pump P to the hydraulic motor M is interrupted. That is, a clutch off state is obtained.

If the eccentric wheel 47 is shifted to the lock-up position 1 when the motor swash plate 19 stands upright, that is, when the motor swash plate 19 is in the top state, all the distributions 46, 46,.
Is closed, the hydraulic motor M is insulated from the high-pressure oil passage 38h and the low-pressure oil passage 38l, and leakage of hydraulic pressure from the hydraulic motor M is reduced. Further, the insulation of the high-pressure oil passage 38h from the hydraulic motor M causes a reduction in the volume of the high-pressure system including the high-pressure oil passage 38h. Is improved in incompressibility. As a result, the transmission efficiency in the top state is improved.

Also, during operation, if hydraulic oil leaks from the hydraulic closed circuit between the hydraulic pump P and the hydraulic motor M, the pressure of the low-pressure oil passage 38l drops below that of the supply oil passage 45, so that the first check valve 43 is opened. Then, the oil pumped from the supply pump 57 to the supply oil passage 45 is supplied to the low-pressure oil passage 38l. Also, at the time of reverse load operation, that is, at the time of engine braking, the hydraulic motor M performs a pump action,
Since the hydraulic pump P functions as a hydraulic motor, the high-pressure oil passage 38h changes to a low pressure, and the low-pressure oil passage 38l changes to a high pressure.
At this time, if hydraulic oil leaks from the hydraulic closed circuit,
Since the pressure of 38h is lower than that of the supply oil passage 45, the second check valve 44 is opened, and oil is supplied from the supply oil passage 45 to the high-pressure oil passage 38h.

C. Effects of the Invention As described above, according to the present invention, the pump cylinder and the motor cylinder are arranged adjacent to each other in the axial direction on the coaxial line, and the opposite end faces of both cylinders are rotatably contacted with each other. A high-pressure groove and a low-pressure groove communicating with the discharge-side group and the suction-side group of the pump port of the pump cylinder on the end face thereof, and an annular high-pressure oil concentrically arranged with the high-pressure groove and the low-pressure groove, respectively. A plurality of radially arranged reciprocating fluid passages communicate with the low pressure oil passage, the high pressure oil passage to the expansion side group of the pump port of the motor cylinder, and the low pressure oil passage to the contraction side group of the motor port. And the eccentric ring which engages with the outer end of the valve to drive the distribution valve is disposed around the motor cylinder, so that the transmission can be reduced in diameter. Moreover, between the opposite end faces of the two cylinders, hydraulic pressure is directly transferred from the pump port to the high-pressure groove and from the low-pressure groove to the pump port, so there is no need to interpose a dedicated distribution plate between the two cylinders. An increase in the axial length of the transmission due to the axially adjacent arrangement of the cylinders can be minimized, and the number of parts can be reduced, which can contribute to further miniaturization and simplification of the structure of the transmission.

A clutch-on position for controlling the stroke of the distribution valve to connect the eccentric wheel to the expansion side group of the pump port of the motor cylinder and the low pressure oil path to the contraction side group of the motor port. The clutch is moved to a clutch-off position for controlling the stroke of the distribution valve to release the oil pressure of the oil passage to the low pressure side, and to a lock-up position for controlling the stroke of the distribution valve so as to cut off communication between the pump port and the motor port. With a mode switching device to obtain
Controlling the transmission in the clutch on, clutch off, and lock up states with a very simple operation of moving a single eccentric wheel to the clutch on position, clutch off position, and lock up position by the mode switching device Therefore, the mode switching device can be easily configured.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a power unit for a motorcycle having a hydrostatic continuously variable transmission of the present invention, and FIGS. 2 and 3 are FIG. 4 and FIG. 5 are sectional views similar to FIG. 3 in different operation modes. M: hydraulic motor, P: hydraulic pump, T: continuously variable transmission, a: pump port, b: motor port, f ...
Clutch off position, l ... Lock-up position, n ... Clutch on position 5 ... Input shaft, 6 ... Output shaft, 9 ... Pump cylinder,
9a: End wall, 10: Cylinder hole, 11: Pump plunger, 12: Pump swash plate, 16: Motor cylinder, 16a
... wall plate, 17 ... cylinder hole, 18 ... motor plunger,
19 ... Motor swash plate, 23 ... Trunnion shaft, 24 ... Swash plate holder, 36h ... High pressure groove, 36l ... Low pressure groove, 38h ... High pressure oil passage, 38l ... Low pressure oil passage, 46 ... Distribution Valve, 47 ... eccentric ring, 2
5 …… Mode switching device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 61/40 F16H 39/14

Claims (1)

(57) [Claims] 1. A hydrostatic continuously variable transmission in which a pump cylinder of a hydraulic pump and a motor cylinder of a hydraulic motor are relatively rotatably disposed, wherein the pump cylinder and the motor cylinder are disposed adjacent to each other in the axial direction on a coaxial line. A high-pressure groove and a low-pressure groove on the motor cylinder, the end surfaces of which communicate with the discharge-side group and the suction-side group of the pump port of the pump cylinder, respectively. Annular high-pressure oil passages and low-pressure oil passages which communicate with the high-pressure grooves and the low-pressure grooves, respectively, and are concentric with each other; the high-pressure oil passages on the expansion side group of the pump ports of the motor cylinder; and the low-pressure oil passages on the motor port. A plurality of distributing valves arranged radially so as to be reciprocally movable to communicate with the contraction side groups, respectively, and engaged with the outer ends of the valves to drive these distributing valves; An eccentric ring is arranged surrounding the motor cylinder, and this eccentric ring is connected to the expansion side group of the pump port of the motor cylinder and the low pressure oil path to the contraction side group of the motor port. A clutch-on position for controlling the stroke of the distribution valve, a clutch-off position for controlling the stroke of the distribution valve to release the hydraulic pressure of the high-pressure oil passage to the low-pressure side, and the same distribution for cutting off the communication between the pump port and the motor port. A hydrostatic continuously variable transmission, comprising: a motor switching device that can be moved to a lockup position for controlling a stroke of a valve.