JPS63246544A - Bonding structure for friction element in automatic transmission with inner circumferential section of drum - Google Patents

Abstract

PURPOSE:To prevent axial increase of the length of transmission due to increase of fitting length of drum caused by boss section, by fitting the boss section formed on the inner circumference of drum in an input shaft then bonding through welding, thereafter fitting a thrust bearing on the outer circumference of the boss section. CONSTITUTION:A boss section 26a is formed through burring on the inner circumference of a drum 26 then it is fitted in a corresponding step section 14a on an input shaft 14, thereafter fitting face is welded through electron beam. The drum 26 is collided against a boss 22a on a pump cover 22 through a thrust bearing 31 fitted over the boss section 26a and positioned axially. In such bearing structure for the drum 32, a collar 33 is stretched into a useless space provided through existence of the thrust bearing 31 so as to bear the drum 32 on the boss 22a through a bush 35 which can slide and rotate on the outer circumferential face of the collar 33, and thereby the bush 35 can be lengthened through effective utilization of useless space. Consequently, the axial dimension of transmission can be reduced corresponding to shortening of the boss 22a.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a structure for connecting the inner peripheral portion of a drum of a friction element for an automatic transmission to a transmission input shaft.

(Prior art) An automatic transmission selects a predetermined gear by selectively hydraulically operating various frictional elements (clutches, brakes, etc.), and shifts to other gears by switching between activation and deactivation of the various frictional elements. It is something.

Therefore, there is a friction element with a drum attached to the input shaft of the transmission, and this drum is usually positioned in the axial direction by abutting against a fixed part via a thrust bearing.

By the way, when attaching the drum to the input shaft, conventionally, the high clutch in page 10 of "Automatic Transaxle RN 4 FO2A Type, RL 4 PO2A Type Maintenance Manual J (A261 C06)" published by Nissan Motor Co., Ltd. As can be seen, the configuration shown in Figure 2 was adopted.In this figure, 1 is the drum of the high clutch,
The inner periphery of the high clutch drum 1 is connected to an input shaft 3 of a transmission by a spline 2, and the drum 1 is brought into contact with the end surface of a hollow fixed shaft 5 via a thrust bearing 4 to be positioned in the axial direction.

However, with this binding structure on the inner circumference of the high clutch drum,
Since a spline is used, it is not possible to transfer the hydraulic pressure to the high clutch hydraulic oil chamber 6 from the input shaft 3.
It is necessary to partially fit the drum 1 onto the hollow fixed shaft 5, and to supply and discharge hydraulic pressure from the hollow fixed shaft 5 to the chamber 6.

On the other hand, an automatic transmission has a friction element having a drum rotating on the hollow fixed shaft, like the reverse clutch in the above-mentioned document, and as shown in FIG. 2, the drum 7 of the reverse clutch is hollow and fixed. It is rotatably fitted onto the shaft 5. Therefore, the reverse clutch also supplies and discharges hydraulic pressure to and from the hydraulic oil chamber 8 from the hollow fixed shaft 5.

For this reason, the operating hydraulic pressure transfer parts for the chambers 6 and 8 both exist on the hollow fixed shaft 5, and they have to be arranged in tandem from the pump cover 9, which increases the length of the hollow fixed shaft 5 and, by extension, the transmission. This resulted in an increase in the length of the axial direction.

Therefore, as in the A240 automatic transmission manufactured by Toyota Motor Corporation, the drum 1 is welded (indicated by 10) to the input shaft 3 as shown in FIG. It was suggested that something like this be done.

(Problem to be solved by the invention) However, in the case of a lever, if the diameter of the weld 10 is small, it is difficult to ensure the strength around the weld, and the base material of the drum 1 must be made of an expensive or thick material. In addition, the welding point is located at the collision point of the thrust bearing 4, and the welding point has to be surface-machined, which significantly reduces workability.
The actual situation was that the diameter of 0 had to be made quite large as shown in Figure 3.

However, if the diameter of the weld 10 is increased in this way, the diameters of parts existing on the outer periphery will become larger, and the radial dimension of the automatic transmission will inevitably increase.

(Means for Solving the Problems) In view of the above-mentioned circumstances, the present invention includes a friction element having a drum connected to an input shaft, and causes the drum to collide with a fixed part via a thrust bearing to cause the drum to move in the axial direction. In the positioned automatic transmission, a boss is formed on the inner periphery of the drum, this boss is fitted to the input shaft and then welded together, and the thrust bearing is fitted on the outer periphery of the boss. It is characterized by its arrangement.

(Function) An automatic transmission selects a predetermined gear position by selectively hydraulically operating various friction elements including the above-mentioned friction elements, and shifts to other gear positions by switching between activation and deactivation of the various friction elements. Can be done.

By the way, in binding the drum of the friction element to the input shaft, a boss part is formed on the inner periphery of the drum, and this boss part is fitted and welded to the input shaft. Even if the welding diameter is made smaller to achieve miniaturization, the mating length of the drum becomes longer, making it possible to ensure sufficient bonding accuracy and bonding strength, and the inner periphery of the drum can be machined by forming the boss. It is hardened and allows the base material of the drum to be made expensive or thick (but still maintain a certain strength of the base material).

In addition, because the thrust bearing is fitted to the outer periphery of the boss, the drum's thrust bearing contact surface is located radially outward from the welding area, so even if the welding diameter is reduced, the welding area cannot be removed. There is no need for surface finishing for thrust bearing collisions, and thrust bearings do not require large weld diameters.

Further, since the boss portion is arranged to overlap in the axial direction with the thrust bearing fitted on the outer periphery of the boss portion, the axial dimension of the transmission is not increased.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 11 indicates a case of an automatic transmission and reference numeral 12 indicates a converter housing. The automatic transmission receives engine power from an input shaft 14 via a torque converter 13 inside a converter housing 12, and uses this power to select various friction elements including a high clutch 15, a reverse clutch 16, and a band brake 17 inside a case 11. It is assumed that the power is transmitted to the countershaft 18 and the final drive pinion 19 through a gear transmission mechanism whose transmission path is determined by hydraulic operation.

An oil pump 20 is provided at the mating surface of the case 11 and the converter housing 12, and the oil is used to control gear shifts, lubricate various parts, and pump the torque converter 1.
3. This oil pump 20 is an internal gear pump housed in a space surrounded by a pump housing 21 and a pump cover 22, and the internal gear is driven by an engine via a pump impeller 13a of a torque converter 13.

The pump cover 22 is made of a light alloy such as aluminum to reduce weight, and a stator shaft 23 made of a steel pipe is fitted into the center of the pump cover 22. In this fitting, the inner periphery of the boss 22a protruding from the pump cover 22 is attached. Connect the stator shaft 23 to the spline (24
) to integrate the pump cover 22 and stator shaft 23. The stator 1 of the torque converter 13 is connected to the end of the stator shaft 23 via the one-way clutch 25.
3b, the input shaft 14 is rotatably inserted into the stator shaft 23, and the turbine runner 13c of the torque converter 13 is connected to the input shaft.

The high clutch 15 has a drum 26 to be connected to the input shaft 14.
In the present invention, this binding is carried out as follows. That is, a boss portion 26a is formed on the inner circumference of the drum 26 by burring, this boss portion is fitted into the corresponding stepped portion 14a of the input shaft 14, and the fitting surface is welded by electron beam welding or laser beam welding (at 27). show). Also high clutch 1
5 is operated by supplying hydraulic pressure to the chamber 28 and moving the piston 29 to the left in the figure.
The hydraulic pressure is transferred to the oil hole 30 formed in the input shaft 14.
We will do this by. Then, the drum 26 is positioned in the axial direction by abutting against the boss 22a of the pump cover 22 via the thrust bearing 31 fitted to the outer periphery of the boss portion 26a, and the thrust bearing contact surface 26b of the drum 26 is finished. good.

The reverse clutch 16 has its drum 32 rotatably fitted onto the boss 22a of the pump cover 22 at its inner peripheral portion. Therefore, the outer periphery of the tip of the boss 22a is made small in diameter, and the collar 33 is press-fitted there.
The length should be such that it protrudes from the free end surface of a.

The race 34 of the thrust bearing 31 is fitted and centered within the projecting end of the collar 33, and the bearing bushing 35 is located within the inner peripheral end of the drum 32 surrounding the outer peripheral surface of the collar 33.
and connect the drum 32 to the collar 33 through this bushing.
bearing on top.

In such a shaft bearing structure for the drum 32, the collar 33 is extended into the wasted space created by the presence of the thrust bearing 31, and the drum 32 is shaft supported on the boss 22a via a bush 35 that slides and rotates on the outer peripheral surface of the collar 33. Therefore, the bush 35 can be made longer by effectively utilizing the wasted space, and by shortening the boss 22a, the axial dimension of the automatic transmission can be reduced accordingly.

Furthermore, as mentioned above, it would be difficult to make the boss 22a from a light alloy such as aluminum, but the centering of the race 34 is done by the projecting end of the separate collar 33 fitted to the boss 22a. can be made durable. In addition, since the race 34 can be attached to the collar 33 by itself, it can also be used as a shim for adjusting the gap between the thrust bearing 31 and the end face of the boss 22a.

Furthermore, since the collar 33 is a small component, the bushing 35
The diameter of the lubrication hole 33a can be made small. In other words, when directly drilling the lubrication hole in a large component such as the pump cover 22, the hole diameter cannot be reduced beyond a certain level;
When forming the lubricating hole 33a in the lubricating hole 33a, it is possible to form the lubricating hole even with a smaller diameter, and it becomes possible to improve the ejection of the lubricating oil.

Further, the spline 24 tends to expand the diameter of the boss 22a when torque or twisting is input to the stator shaft 23, but the collar 33 can also serve as a reinforcing ring to suppress this tendency. As shown in FIG. 1, in the above-described embodiment, the boss portion 26a and the thrust bearing 31 and the thrust bearing 31 and the collar 33 are arranged so as to overlap each other in the radial direction, and the axial dimension of the automatic transmission is Although it is shortened, the boss part 2 is also shortened, although it is not particularly shown.
66a and the collar 33 can also be arranged so that they overlap, and the axial dimension of the -i automatic transmission can be shortened.

(Effects of the Invention) Thus, the drum inner circumferential binding structure of the present invention has the following features as described above:
A boss portion 26a is formed on the inner circumference of the drum, and this is connected to the input shaft 14.
Even if the diameter of the weld 27 is made smaller in order to make the automatic transmission smaller in the radial direction, the length of the weld 26 that is fitted to the drum 26 becomes longer, making it difficult to maintain sufficient bonding accuracy and bonding strength. In addition, the inner peripheral portion of the drum is work-hardened by forming the boss portion 26a, and a predetermined strength of the base material can be maintained without having to make the base material of the drum expensive or thick.

In addition, since the thrust bearing 31 is fitted and disposed on the outer periphery of the boss portion 26a, the thrust bearing contact surface 26b of the drum is located radially outward from the welding location 27, so even if the welding diameter is made small, , there is no need to surface finish the weld location for thrust bearing impact, and the thrust bearing does not cause a need to increase the weld diameter. Further, since the outer periphery of the boss portion 26a is fitted with the thrust bearing 31, the boss portion 26a is arranged to overlap within the axial dimension of the thrust bearing 31, so that the axial dimension of the boss portion 26a is the same as that of the automatic transmission. There is no increase in the axial dimension.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of an automatic transmission showing an embodiment of the present invention, and FIGS. 2 and 3 are sectional views showing a conventional drum inner circumferential binding structure. 13... Torque converter 14... Input shaft 15
...High clutch (friction element) 16...Reverse clutch 17...Band brake 20...Oil pump 21...Pump housing 22...Pump cover 23...Stator shaft 26...Drum 26a...
Boss portion 26b... Thrust bearing contact surface 27...
・Welding 31...Thrust bearing

Claims (1)

[Claims] 1. A friction element having a drum connected to an input shaft;
In an automatic transmission in which the drum is positioned in the axial direction by abutting the drum against a fixed part via a thrust bearing, a boss part is formed on the inner periphery of the drum, and this boss part is fitted to the input shaft and then welded. A structure for binding an inner circumferential portion of a drum of a friction element for an automatic transmission, characterized in that the thrust bearing is fitted onto the outer periphery of the boss portion.