JPH0113878Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a thrust bearing for an automatic transmission, and more particularly, to a thrust bearing for an automatic transmission that can be applied to a clutch of an automatic transmission for a vehicle using a Ravignio planetary gear. be.

4 forward speeds and 1 reverse speed using Ravioni planetary gears
A conventional automatic transmission that creates gears is shown in FIG. In other words, the crankshaft 4 of the engine 2, which serves as a power source for the vehicle, is directly connected to the pump 8 of the torque converter 6. Torque converter 6
has a pump 8, a turbine 10, a stator 12, and a one-way clutch 14. The stator 12 is connected to a case 16 via the one-way clutch 14, and the one-way clutch connects the stator 12 to the case 16.
rotates in the same direction as the crankshaft 4, but is not allowed to rotate in the opposite direction. The torque transmitted to the turbine 10 is transmitted by an input shaft 20 to a gear transmission 22 disposed at the rear thereof that achieves four forward speeds and one reverse speed.
The transmission 22 includes three sets of clutches 24, 26,
28, two sets of brakes 30, 32, one set of one-way clutch 34, and one set of Ravignio type planetary gear mechanism 36. Planetary gear mechanism 3
6 is a ring gear 38, a long pinion gear 4
0. Carrier 4 as a power transmitted body that rotatably supports the short pinion gear 42, front sun gear 44, and rear sun gear 46 and is also rotatable.
The ring gear 38 is connected to the output shaft 50, the front sun gear 44 is connected to the input shaft 20 via the kickdown drum 52 and the front clutch 24, and the rear sun gear 46 is connected to the input shaft 20 via the rear clutch 26. connected to
The carrier 48 is connected to the case 16 via a low reverse brake 32 and a one-way clutch 34, which are arranged so as to be functionally parallel to each other, and a four-speed clutch 28 arranged at the rear end of the gear transmission 22. It is connected to the input shaft 20 via. The kickdown drum 52 can be fixedly connected to the case 16 by a kickdown brake 30. The torque passing through the planetary gear function 36 is transferred from an output gear 60 fixed to an output shaft 50 to an idle gear 62 to a driven gear 64.
A differential gear device 72 is connected to a drive shaft 70 via a transfer shaft 66 fixed to a driven gear 64 and a helical gear 68.
transmitted to.

Each of the above-mentioned clutches and brakes is composed of a friction engagement device equipped with an engagement piston device or a servo device, etc., and is connected to a pump 8 of a torque converter 6 to drive an oil pump (not shown) by the engine 2. It is operated by hydraulic pressure generated by The hydraulic pressure is selectively supplied to each clutch and brake by a hydraulic control device according to the operating state detected by various operating state detection devices, and the movement is controlled by a combination of the operation of each clutch and brake. Four reverse gears and one gear stage are achieved.

In the automatic transmission configured as described above, the clutch 28 is mounted at an end inside the case 16. In this clutch mechanism, the clutch plate is integrally attached to a retainer, and this retainer is configured to fit into a spline shaft formed on the input shaft 20 and to be able to slide in the axial direction.

Therefore, a means for restricting excessive movement of the retainer in the axial direction, such as a thrust bearing, is required. However, if a commercially available thrust bearing is used as this thrust bearing, it not only requires a relatively large occupied space, but also requires a bearing that can withstand high peripheral speeds in terms of bearing performance.
Due to various difficulties, it is desired to provide a suitable thrust bearing for an automatic transmission.

The present invention has been made in view of this problem, and an object of the present invention is to provide a thrust bearing for an automatic transmission that occupies a small space and has good durability.

The configuration of the present invention will be explained below based on one embodiment.

In FIG. 2, a four-speed clutch 28 is disposed at the right end of the input shaft 20. The clutch 28 is composed of a pair of a driving-side clutch plate 80 and a driven-side clutch plate 82, and power transmission is connected or disconnected depending on whether these members are pressed against or separated from each other.

More specifically, a dish-shaped retainer 84 is spline-fitted to the right end of the input shaft 20, and a clutch plate 80 is attached to the inner peripheral surface of the cylindrical outer diameter wall.
has been planted.

On the other hand, a clutch plate 82 disposed opposite to this clutch plate 80 has a plate-shaped clutch hub 86.
It is planted on the outer peripheral surface of the outer wall.

This clutch hub 86 is fitted into a spline formed on the outer periphery of a cylindrical hollow shaft 88 that is rotatably inserted and supported by the input shaft 20.
Further, the left end surface of the clutch hub 86 is connected to the inner race 94 of the ball bearing 92 via a thrust washer 90.
is in contact with Outer race 95 of ball bearing 92
is built into the automatic transmission body, so in the end,
Movement of the clutch hub 86 to the left in the axial direction of the input shaft when the clutch is operated is restricted by the inner race 95 via the thrust washer 90.

Next, the retainer 84 that is spline-fitted to the input shaft 20 has a boss 84a protruding from the right side of its center, and this part is attached to the inner peripheral wall of the circular recess 16a formed on the inner wall of the case 16 with a seal ring. 9
6, and are slidably fitted together.

The retainer 86 also has a boss 84 on its left side.
b is prominent. A disk-shaped piston 98 is slidably and rotatably mounted on the outer periphery of the boss 84b via a seal ring 98a. boss 8
A bell spring 100 is fixed on the left side of the piston 98 on the piston 4b, and the force of this spring constantly pushes the piston 98 to the right. When the clutch 28 is in the disengaged state, this spring 100
The piston 98 is pressed until it comes into contact with the retainer 84 due to the force.

The clutch 28 becomes connected when the piston 98 presses against the clutch plate 82 by pushing the clutch plate 80.

The piston 98 is operated against a spring force by pressure oil supplied from a hydraulic pressure supply switching valve (not shown) communicating with a hydraulic chamber 102 provided between the piston 98 and the retainer 84 via an oil passage 104 . In addition, oil passage 10
4 and the hydraulic chamber 102 are connected to the hydraulic chamber 102.
It is located on the inside in the radial direction so that the oil entering the hydraulic chamber 102 receives centrifugal force and fills the hydraulic chamber 102. Furthermore, a discharge port 106 for discharging the oil in the hydraulic chamber 102 is provided on the outside of the piston 98 in the radial direction within the hydraulic chamber 102. A discharge valve 108 is provided which is closed and opened by centrifugal force when the oil pressure falls below a specified value.

Therefore, when pressure oil is supplied from the hydraulic pressure supply switching valve, the pressure causes the discharge valve 108 to close to the discharge port 1.
06 and push the piston 98. Then, when the hydraulic pressure supply switching valve switches to stop the supply of pressure oil, the pressure in the hydraulic chamber 102 decreases, and the discharge valve 108 moves by centrifugal force, opening the discharge force 106. In this way, the hydraulic chamber 10
The position of the piston 98 is controlled in accordance with the hydraulic pressure of the oil sent to the clutch 28, and eventually the engagement/disengagement state of the clutch 28 is controlled. When the clutch 28 is in the connected state, power from the input shaft 20 is transmitted to the clutch hub 86 via the clutch 28, and further via the hollow shaft 88 to the carrier 110 which is spline-fitted with the hollow shaft 88. transmitted to.

As described above, the automatic transmission shown in FIG. 2 includes the clutch 28 that operates to connect and disconnect the input shaft 20 and the hollow shaft 88 as a power receiving body. In such an automatic transmission, the retainer 8
4 from moving excessively to the right in the axial direction, in the present invention, a stepped portion consisting of a circular recess is formed at the right end of the hollow portion of the boss 84a existing in the center of the retainer 84, and the stepped portion is formed in the stepped portion. A disc-shaped bearing plate 112 is press-fitted and fixed. Furthermore, the inner wall of the case 16 facing the bearing plate 112, that is, the bottom wall of the circular recess 16a, is connected to the bearing plate 112.
A steel ball 120 that can come into contact with the center of rotation (shown as point a in FIG. 2) is supported. That is, a convex portion 114 is formed on the inner wall of the case 16, and a steel ball 12 is inserted into a hole 121 formed at the center of the convex portion.
Embed 0. The steel ball 120 contacts the bottom of the hole 121 and partially protrudes from the hole 121.
In order to prevent the steel ball from coming off the hole, the peripheral edge of the hole 121 is caulked with a punch. For this reason,
Although the steel ball 120 does not move even if it receives a thrust force to the right in the axial direction, the steel ball itself may rotate or may not rotate. Depending on the case, insert steel ball 1 into hole 121.
20 may be press-fitted.

According to such a thrust bearing of an automatic transmission, when the retainer 84 moves to the right in the axial direction,
The center of rotation a of the bearing plate 112 is attached to the steel ball 120.
contact, and excessive movement of the retainer 84 can be restricted.

Here, since the steel balls 120 contact the center of rotation a on the retainer 84 side in a state close to point contact, the relative speed becomes the smallest and can approach zero. Moreover, since the steel balls 120 are present in the middle of the oil passage 104, a thrust bearing with good lubricity and less bearing negative can be formed. Here, the results of a durability characteristic test of a thrust bearing to which the present invention is applied, conducted by the present inventor, are shown in FIG.

This durability characteristic test was conducted at a relative rotation speed of 2500 rpm.
This was done with the lubricant removed.
The solid line in the figure represents the durability characteristics of the thrust bearing according to the present invention using steel balls 120. The broken line in Fig. 3 shows the convex portion 114 without steel balls and the bearing plate 1.
The durability characteristics of the thrust bearing due to direct contact with No. 12 are shown as comparative values.

As described above, since the thrust bearing for an automatic transmission according to the present invention can be constructed by attaching a thin bearing plate and relatively small diameter steel balls 120 to the case 16, it does not require a special occupied space. Furthermore, the sliding contact portion is a spherical contact, which has the advantage of suppressing the occurrence of problems such as wear and seizure, and ensuring sufficient durability.

[Brief explanation of the drawing]

Fig. 1 is a gear train diagram showing a schematic structure of an automatic transmission suitable for carrying out the present invention, Fig. 2 is a cross-sectional view of the thrust bearing section according to the invention shown together with a specific example of the structure shown in the above figure, and Fig. 3 is a gear train diagram showing the schematic structure of an automatic transmission suitable for implementing the present invention. 3 shows durability characteristic diagrams of thrust bearings for automatic transmissions according to the present invention. 20...Input shaft, 80...Clutch plate, 84...
...retainer, 88 ... hollow shaft, 112 ... bearing plate, 114 ... convex portion, 120 ... steel ball.

Claims (1)

[Scope of utility model registration request] A clutch is disposed at the inner end of the case that operates to connect and disconnect between the input shaft incorporated in the case of the automatic transmission and the power transmitted body when the automatic transmission achieves a predetermined gear position. In the automatic transmission, a bearing plate is provided at the center of a retainer that includes a clutch plate of the clutch and is spline-fitted to the input shaft so as to be slidable in the axial direction, and a bearing plate of the case that faces the bearing plate. A thrust bearing for an automatic transmission, comprising a sphere supported on an inner wall so as to be able to come into contact with the bearing plate.