JPS6272955A - Hydraulic transmission for vehicles - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention provides a motor cylinder of a swash plate type hydraulic motor surrounding a swash plate type hydraulic pump, in which a distribution end wall is provided, and the distribution end wall is provided with a distribution end wall. Basically, a cylindrical support shaft is fixedly installed to define an oil chamber.
A fixed shaft having a distribution ring at its tip that slides on the distribution end wall and divides the oil chamber into a high pressure oil chamber and a low pressure oil chamber is inserted into the support shaft, and the distribution end wall is connected to the hydraulic pump and the distribution ring. Hydraulic oil is transferred between the hydraulic motor, the high-pressure oil chamber, and the low-pressure oil chamber. Regarding transmission.

(2) Conventional technology Conventionally, in such hydraulic transmissions, the seal of the low-pressure oil chamber is provided through a contact type seal member, such as a seal ring, between the support shaft that rotates together with the motor cylinder of the hydraulic motor and the fixed shaft. This is done by dressing.

(3) Problems to be solved by the invention By the way, in such a hydraulic transmission, the hydraulic motor produces a pumping action when the vehicle decelerates, and the discharge of the pump causes the hydraulic pump to rotate as a motor, so that engine braking is not achieved. However, if such a deceleration effect occurs during high-speed running, high rotational friction and high pressure will act on the seal member, which is unfavorable in terms of durability of the seal member.

Therefore, it is conceivable to interpose a non-contact type seal member having a predetermined gap between the supporting shaft and the fixed shaft at least one of them.

However, as the oil temperature rises, the viscosity of the hydraulic oil decreases, so the amount of oil leaking from the gap increases, thereby reducing the engine braking effect.

The present invention has been made in view of the above circumstances, and provides a vehicle in which a seal is formed between a support shaft and a fixed shaft to prevent the engine braking effect from decreasing due to an increase in oil temperature and to ensure durability. The purpose is to provide a hydraulic transmission for

U9 Structure of the Invention [IJ Means for Solving the Problems According to the present invention, one of the fixed shaft and the support shaft has a seal portion formed of a material with a higher thermal expansion coefficient than the other. A small annular gap is formed between the two.

(2) Effect Since the seal portion provided on one of the fixed shaft and the support shaft does not come into contact with the other of the fixed shaft and the support shaft, durability is improved. Moreover, the annular minute gap becomes smaller as the oil temperature rises, and a sufficient sealing function can be achieved regardless of a decrease in the viscosity of the hydraulic oil.

(3) Examples Examples of the present invention will be explained below with reference to the drawings.
First, in FIG. 1 showing a first embodiment of the present invention, a vehicle transmission device is constituted by a hydraulic continuously variable transmission T and a forward and reverse gear device G.

G is housed in the mission case 7.

The hydraulic continuously variable transmission T is composed of a constant displacement swash plate hydraulic pump P and a variable displacement hydraulic motor II.

The hydraulic pump P has a pump cylinder 4 with an input shaft 2 protruding from the left side and a support shaft 3 from the right end. They are connected to each other so as to be movable only in the axial direction, and their distal ends penetrate the left side wall of the mission case 1 and protrude to the outside, where they are connected to a flywheel 6 attached to the engine crankshaft E.

The pump cylinder 4 has a large number of through stepped cylinder holes 7, 7.
... are bored in an annular arrangement surrounding the center of rotation of the cylinder 4, and in the illustrated example, each stepped cylinder hole 7 has a large diameter hole γj on the left half and a small diameter hole γγ on the right half, and the stepped portion thereof is formed on the pressure receiving surface 8.

A pair of opposing large and small pump plungers 9# and 9r slide into each stepped cylinder hole γ to define a pump oil chamber IA therebetween. Both plungers 96.9r each have a cylindrical shape with a bottom facing toward the outer end, and a coil spring 11 is accommodated in the hollow portion of the large-diameter pump plunger 91 to urge both plungers 91.91- away from each other. ,
The hollow portion of the small diameter pump plunger 9r is provided with the spring 11.
The base of a spring guide rod 10 is fitted therein to prevent its buckling. The spring guide rod 10 is made of a material having a lighter specific gravity than the pump plunger 91,97-.

10,000, the hydraulic motor M surrounds the pump cylinder 4,
It has a motor cylinder 12 concentric therewith, in which a number of through cylinder holes 13, 13... are bored in an annular arrangement surrounding the center of rotation of the cylinder 120,
Further, a distribution end wall 12a is integrally formed at the right end thereof.

A pair of opposing motor plungers 141, 14r of the same diameter slide into the six holes 13, and the motor oil chamber 1 is inserted between them.
Define 3A. Furthermore, a hollow output shaft 16 and a basically cylindrical support shaft 1 are provided on both left and right end surfaces of the motor cylinder 12.
7 are fixed by bolts 15, respectively, and the output shaft 1
6 is supported on the left end wall of the mission case 1 via a bearing 18 on its outer circumferential surface, and a bearing 19 is supported on its inner circumferential surface.
．． The input shaft 2 is supported via 20. Also, the support shaft 17
is the outer peripheral surface of the transmission case 1 via the bearing 21.
is supported on the right end wall of the The motor cylinder 12 supports the support shaft 3 of the pump cylinder 4 via a bearing 22 inside thereof, and brings the end surface of the support shaft 3 into close contact with the distribution end wall T2a. A seal ring 23 is fitted onto the outer periphery of the end of the support shaft 3 so as to be in contact with the inner peripheral surface of the motor cylinder 12 .

Further, inside the motor cylinder 12, there are a pair of left and right pump ramps arranged symmetrically and in contact with the outer ends of the left pump plunger group 91 group and the right pump plunger group 9r at a fixed angle with respect to their respective axes. Plate 241, 24r
is thrust and radial bearing 25g, 2611
; Supported via 25r and 26r. Thus, when each pump swash plate 241° 24r rotates relative to the motor cylinder 12, it cooperates with the coil spring 11 to give reciprocating motion to each pump plunger 91, 91 group to repeat the suction and discharge strokes. I can do it.

Moreover, in the hydraulic motor M, the left motor plunger 141! a pair of left and right motor swash plates 27# that abut each outer end of the group and the right motor plunger 14r group, respectively;
27r are arranged symmetrically.

These motor swash plates 276.2γr are connected to thrust and radial bearings 281, 291; 28r.

The swash plate frames 311 and 31r are respectively supported via 29r.
each integrally has a trunnion shaft (not shown) having an east exit line perpendicular to the rotational axis of the motor cylinder 12, and these shafts are rotatably supported by the mission case 1 and are connected to a motion device (not shown). are interlocked and connected to each other via Thus, both motor swash plates 271.27r can be tilted symmetrically from an upright position perpendicular to each motor plunger group 141.14r to the maximum tilted position shown, and in those tilted positions the motor cylinder 12 rotates. At this time, each group of motor plungers 1411.14r can be sequentially reciprocated to repeat the expansion and contraction strokes, and the sliding stroke of these plungers 141.14r is determined by the inclination angle of motor swash plate 27L27r.

A hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M as follows. That is, an oil chamber 38 facing the distribution end wall 12a is formed on the support shaft 17 of the motor cylinder 12, and in the oil chamber 38, a number of communication boats 39, 39, . . . Discharge boat 41
and the suction boat 42 are opened, and the open end of the discharge boat 41 is on the rotation center line of the motor cylinder 12, the open ends of the communication boats 39, 39, etc. are on the same circle surrounding the discharge boat 41, and the suction boat 42 are located outside of the 39 groups of communication boats. A fixed shaft 44 that is positioned and fixed to the mission case 1 via a positioning pin 43 is a support shaft 1.
The distribution ring 45 enters the oil chamber 38 from the outer ring of No. 7, and the distribution ring 45 is located at the end of the entry while the motor cylinder 12 is rotating! It is installed with a certain amount of deviation from the position.

This distribution ring 45 slides on the distribution end wall 12aK to divide the oil chamber 38 into an inner high pressure oil chamber 38h and an outer low pressure oil chamber 38A, and connects the discharge boat 41 and the expansion stroke motor via the high pressure oil chamber 3sht. The communication boat 39 is connected to the oil chamber i3A, and is connected to the suction boat 42 and the motor oil chamber 13, -1 in the contraction stroke via the low pressure oil chamber 38A.
communicate with. On the other hand, at the end of the support shaft 3 of the pump cylinder 4 that contacts the distribution end wall 12a, a large number of communication boats (47, 47, etc.) connected to each pump oil chamber 7A are opened, and among these boats, The pump oil chamber 7A is connected to the discharge port 41, and the pump oil chamber 7A in the suction stroke is connected to the discharge port 41.
The suction boats 42 are connected to the suction boats 42, respectively.

In the above configuration, when the pump cylinder 4 is rotated via the input shaft 2 due to the rotation of the engine crankshaft E, the high pressure oil generated in the pump oil chamber 7A due to the discharge stroke of the pump granger sg+sr will be transferred to the discharge port 41 at high pressure. The oil flows into the oil chamber 38h, via the communication boat 39 in communication with the oil chamber 38h, and into the motor oil chamber 13/1 in the expansion stroke to apply thrust to the opposed plungers 14g and 14r facing the oil chamber, while the motor plunger in the contraction stroke 141, 147-, the hydraulic oil discharged is returned to the pump oil chamber 7A in the suction stroke via the communication boat 39 and the suction boat 42, which communicate with the low pressure oil chamber 281. During this time, the pump plunger 91 in the discharge stroke! , 91- is the bo/pu swash plate 24A! , 24r to the motor cylinder 12, and the expansion stroke motor plungers 141, 14r act on the motor swash plate 2.
The motor cylinder 12 rotates due to the phase with the reaction torque received from 71 and 2γr, and the output is output from the output 16.

In this case, motor cylinder 1 relative to pump cylinder 4
The gear ratio of 2 is given by the following equation.

As is clear from the above equation, if the capacity of the hydraulic motor Af is changed from zero to the maximum value, the gear ratio can be changed to the required value consisting of 1, and the capacity of the hydraulic motor Al is changed by the opposing motor plungers 14g and 14r. Therefore, by tilting both motor swash plates 27g and 27r from the upright position to the maximum inclination angle as described above, the above-mentioned speed change action can be obtained steplessly.

The fixed shaft 44 is formed hollow, and a short circuit boat 5 is provided on the side wall of the fixed shaft 44 to communicate between the high and low pressure oil chambers 38h and 381.
1 is bored, and a cylindrical clutch valve 52 for opening and closing the boat 51 is rotatably fitted into the hollow part of the fixed shaft 44. The clutch valve 52 has a control groove 53 on the side wall of its distal end, and a rotating plate 5 connected to a clutch control device (not shown) at its base end.
4, and by rotating the rotating plate 54, the control groove 53 is aligned with the shorting port 51, and the shorting port 51 is connected to the shorting port 51.
When fully opened, the clutch is off; when the control groove 53 is moved from the position of the shorting boat 51 to fully close the shorting boat 51, the clutch is on (as shown); when the shorting boat 51 is half open, the clutch is half-clutched. The state is obtained. That is, in the clutch off state, the hydraulic oil discharged from the discharge boat 41 to the high pressure oil chamber 38h passes through the short-circuit port 51 to the low pressure oil chamber 38#, and therefore immediately short-circuits to the suction boat 42, disabling the hydraulic motor Af, and In the clutch-on state, the short circuit of the hydraulic oil as described above is prevented, the hydraulic oil is circulated from the hydraulic pump P to the motor Jf, and normal transmission is performed.

The clutch valve 52 has a built-in hydraulic servo motor 57 that is operated by a pilot box 55, and the tip of the servo piston 58 is formed into a valve rod 58a having a smaller diameter than the inner diameter of the clutch valve 52 and plunges into the high pressure oil chamber 38A. A closure valve 59 for the discharge boat 41 is swingably attached to its tip.

The discharge boat 41 can be closed by moving the servo piston 58 to the left to bring the closing valve 59 into close contact with the distribution end wall 12aK. This blockage is performed when the motor swash plate 271.degree. 27r is placed in an upright position and the gear ratio is controlled to 1:1. , 9r are hydraulically locked to remove the pump plunger 97 from the pump cylinder 4.
．． The motor cylinder 12 can be mechanically driven via the 9r group and the pump swash plates 241 and 24r, and as a result, the thrust of the motor plungers 14/14 and 14γ to the motor swash plates 271 and 27r disappears. The load on each bearing due to thrust is removed.

Referring also to FIG. 2, a seal portion 60 is provided on the outer peripheral surface of the fixed shaft 44 in order to seal the low pressure oil chamber 38g. This seal part 60 is formed by fixing a ring-shaped part to the outer circumferential surface of the fixed shaft 44, and the fixing structure may be any of fitting, adhesion, and pressure bonding, or it may be plated. Alternatively, the knoll portion 60 may be formed by thermal spraying. Moreover, the outer surface of this seal portion 60 and the support shaft 17
An i-annular minute gap 61 is formed between the inner surface of the i-ring and the inner surface.

Incidentally, the amount of fluid leakage Q between two concentrically arranged members is generally given by the following equation.

Here, the code d is the diameter of the inner member, the code is the distance between the inner and outer members, the code ΔP is the pressure difference between the parts to be sealed, the code l is the length of the part with the sealing structure, and the code μ is Fluid viscosity.

As is clear from the above equation, when the temperature of the hydraulic oil increases and the viscosity μ decreases, the leakage amount Q increases, and in order to reduce this leakage amount Q, it is desirable to reduce the interval. It will be done.

Therefore, according to the present invention, the seal portion 60 is formed of a material having a higher coefficient of thermal expansion than the support shaft 17. Then, when the oil temperature rises, the seal portion 60 expands in the radial direction at a larger rate than the support shaft 17, and the minute gap 61 becomes smaller. This makes it possible to reduce the amount of leakage Q. In addition,
The minute gap 61 is set depending on the required engine braking effect.

Referring again to FIG. 1, the forward and reverse gear device G includes a pair of drive gears 79. fixed to the output shaft 16. .

19□, one drive gear 79. A driven gear 80. that meshes with the driven gear 80. and the other driven gear 802 meshing with the driving gear γ9□ via the intermediate gear 81 are rotatably provided on the subshaft 7, which is rotatably supported on the mission case 1 parallel to the output shaft 16. It will be done. Both driven gears 81. ,81
．． has driving clutch gears 82, 1822 integrally in each opposing part, and a driven clutch gear 83 fixed to the subshaft γ8 is disposed between them, and this latch gear 83 is always engaged with the driven clutch gear 83. Via an annular clutch member 84, drive clutch gear 82. Alternatively, it can be selectively linked to 82□.

Further, the subshaft 78 is provided with a gear (not shown) connected to a differential device (not shown), and the actuating device switches between the forward and reverse directions of the vehicle in response to the operation of the clutch member 84 to drive the vehicle. be done.

Next, the operation of this embodiment will be explained.
0 does not contact the support shaft 17, so even if a deceleration effect occurs when the vehicle is running at high speed, high rotational friction and high pressure will not be applied to the seal portion 60 (this will improve durability). Furthermore, the minute gap 61 between the seal portion 60 and the support shaft 17 is set so as to obtain a sufficient engine braking effect, so that even with a non-contact type, sufficient engine braking can be obtained.

Furthermore, assuming that the temperature of the hydraulic oil increases, the minute gap 61 becomes smaller, so that a sufficient sealing function can be obtained despite the decrease in the viscosity of the hydraulic oil, thus preventing a decrease in the engine braking effect. Ru.

FIG. 3 shows a second embodiment of the present invention, in which, contrary to the above-mentioned embodiments, a seal portion 62 formed of a material having a higher coefficient of thermal expansion than the fixed shaft 44 is attached to the fixed shaft 44. It is provided on the inner surface of the support shaft 17 with a minute gap 63 formed between it and the outer peripheral surface.

4, 5, and 6 show the third, fourth, and fifth embodiments of the present invention, respectively. In the third embodiment, the outer surface of the seal portion 64 provided on the fixed shaft 44 is A plurality of annular grooves 65 are provided, and in the fourth embodiment, a plurality of annular grooves 66 are provided on the inner surface of the support shaft 1γ at a portion facing the seal portion 60 provided on the fixed shaft 44, and in the fifth embodiment, a plurality of annular grooves 66 are provided on the inner surface of the support shaft 1γ. A plurality of annular protrusions 68 are provided on the seal portion 67 provided on the support shaft 17, and a plurality of annular grooves 69 are provided on the inner surface of the support shaft 17 corresponding to the annular protrusions 68.

In such third to fifth embodiments, the flow resistance of the hydraulic oil becomes large, and the leakage of the hydraulic oil is further reduced.

FIG. 7 shows the sixth cusp embodiment of the present invention.
11144 is formed of a material having a higher coefficient of thermal expansion than the support shaft 17, and this fixed shaft 44 has an annular minute gap 70 formed between it and the inner surface of the support shaft 17. A sealed seal portion 71 is integrally provided.

FIG. 8 shows a seventh embodiment of the present invention. In addition to the seal portion 60 similar to the first embodiment, a bearing 72 is interposed between the support shaft 17 and the fixed shaft 44. 72 prevents the support shaft 17 from deflecting.

FIG. 9 shows an eighth embodiment of the present invention, in which a seal portion 73 having a two-layer structure is provided on the outer surface of the fixed shaft 44. That is, the seal portion 73 includes an inner ring portion 74 having a larger coefficient of thermal expansion than the support shaft 17, and a portion between the support shaft 17 and the inner ring portion 74.
The outer ring part 5 has a larger coefficient of thermal expansion than the outer ring part 5, and by adjusting the thickness of the outer ring part 76, the amount of change in the minute gap 76 between the support shaft 17 and the seal part 73 can be adjusted. Adjustable.

C"0 Effects of the Invention As described above, according to the present invention, one of the fixed shaft and the support shaft is provided with a seal portion formed of a material having a higher coefficient of thermal expansion than the other. Since it is provided by forming a small annular gap, by reducing the small gap as the oil temperature increases, it is possible to prevent leakage of hydraulic oil as much as possible, prevent a decrease in engine braking effect, and improve durability. can also be improved.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a longitudinal sectional side view of a vehicle transmission, FIG. 2 is an enlarged sectional view of the main part of FIG. 1, and FIG. figure. 4, 5, 6, 7, 8, and 9 are the second embodiments of the present invention. Third. 4th. Fifth. 6. It is a sectional view corresponding to FIG. 2 of the seventh and eighth embodiments. 12...Motor cylinder, 12a...Distribution end wall, 1
7... Support shaft, 38... Oil chamber, 38A... High pressure oil chamber, 381... Low pressure oil chamber, 44... Fixed shaft, 45...
・Distribution ring, 60°62.64, 67.71.73...
Seal part, 61°63.70.76...Minor gap, M
... Swash plate type hydraulic motor, P... Swash plate type hydraulic pump Patent applicant Honda Motor Co., Ltd. 1S3 Figure A Figure 5 Figure 2 Figure 4 ii1 Figure 9 Figure 6 Figure 8

Claims (1)

[Claims] A motor cylinder of a swash plate type hydraulic motor surrounding a swash plate type hydraulic pump is provided with a distribution end wall, and a basically cylindrical support shaft defining an oil chamber is fixed to the distribution end wall. A fixed shaft having a distribution ring at its tip that slides against a wall and divides the oil chamber into a high-pressure oil chamber and a low-pressure oil chamber is inserted into the support shaft, and the distribution end wall is connected to the hydraulic pump and the hydraulic pressure chamber. In a vehicle hydraulic transmission configured to transfer hydraulic oil between a motor, the high-pressure oil chamber, and the low-pressure oil chamber, and in which the hydraulic pump and the hydraulic motor are connected to form a hydraulic closed circuit. , characterized in that one of the fixed shaft and the support shaft is provided with a seal portion formed of a material having a higher coefficient of thermal expansion than the other, with a small annular gap formed between the seal portion and the other. Hydraulic transmission for vehicles.