JP2654060B2 - Hydraulically operated multi-disc brake for automatic transmission - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a hydraulically actuated multiple disc brake for an automatic transmission, and more particularly to an efficient arrangement of the brake.

(Prior Art) An automatic transmission is configured by housing a gear transmission mechanism in which a gear position is determined by a selection operation of various friction elements such as a hydraulic clutch, a hydraulic brake and a one-way clutch in a transmission case. Conventionally, as an automatic transmission, of a variety of friction elements, a one-way clutch and a hydraulically actuated multi-plate brake are disposed adjacent to each other in the axial direction and fitted around the inner periphery of a transmission case. Among them, there is a type in which a hydraulically actuated multiple disc clutch is disposed on the inner periphery of the above-mentioned hydraulic actuated multiple disc brake.

1984 Nissan Motor Co., Ltd. “Automatic Transaxle RN4F02A, RL4F02A Maintenance Instructions” (A261C0
The automatic transmission shown on page 10 of 6) corresponds to this. In this automatic transmission, a low reverse brake is used for the certain hydraulically operated multiple disc brake, and a low clutch is used for the certain hydraulically operated multiple disc clutch. And one-way clutches respectively correspond to the certain one-way clutch.

(Problems to be Solved by the Invention) However, in this automatic transmission, since the operating piston of the low reverse brake is disposed farther from the one-way clutch with respect to the brake disk of the brake,
The following problems arise. That is, in such an arrangement of the brake operation piston, the piston is located on the inner periphery of the end of the transmission case which can be reduced in diameter, and the end of the transmission case is enlarged. However, in order to suppress the increase in the diameter, the working piston of the low clutch on the inner periphery of the brake is limited in diameter.

(Means for Solving the Problems) According to the present invention, in the automatic transmission of the type described above, a dead space exists between the certain hydraulically actuated multi-plate clutch and the certain one-way clutch due to the configuration of the gear transmission mechanism. By relocating the working piston of a hydraulically actuated multi-plate brake, the above-mentioned problem can be solved. In addition, various advantages can be obtained by increasing the pressure receiving area of the working piston without increasing the external size of the automatic transmission. In view of the fact that the transmission gear case can be used, a gear transmission mechanism whose gear position is determined by the selection operation of various friction elements is housed in the transmission case, and a certain one-way clutch and a certain hydraulic operation load among the various friction elements are contained. The plate brake and the plate brake are disposed adjacent to each other in the axial direction and fitted on the inner periphery of the transmission case, and among the various friction elements, a hydraulically operated multi-plate clutch is disposed on the inner periphery of the certain hydraulically operated multi-plate brake. In the placed automatic transmission, the operating piston of the certain hydraulically operated multi-plate brake is viewed in the axial direction, and disposed between the brake disc of the certain hydraulically operated multi-plate brake and the certain one-way clutch, The inner diameter of the pressure receiving surface of the working piston is reduced in diameter so as to overlap the certain hydraulically actuated multi-plate clutch when viewed in the axial direction.

(Operation) The automatic transmission determines the gear position of the gear transmission mechanism by selecting and operating various friction elements including a certain one-way clutch, a certain hydraulically operated multi-plate brake, and a certain hydraulically operated multi-plate clutch. The input power is shifted according to the ratio and output.

By the way, since the working piston of a certain hydraulically operated multi-disc brake is viewed in the axial direction and disposed between a brake disk of the brake and a certain one-way clutch, the operating piston is connected to a certain hydraulically operated multi-disc clutch and a certain one-way clutch. In the dead space between the one-way clutches. For this reason, the brake actuation piston is not located at the end of the transmission case that can be made smaller in diameter, so that the end of the transmission case does not increase in diameter, and a certain hydraulic actuation at the end of the transmission case does not occur. There is no situation in which the working piston of the multiple disc clutch must be reduced in diameter.

Further, since the inner diameter of the pressure receiving surface of the working piston is reduced so as to overlap the certain hydraulically actuated multi-plate clutch when viewed in the axial direction, the pressure receiving area of the working piston is maintained without changing the external dimensions of the automatic transmission. Can be increased. In this case, it is possible to reduce the number of brake disks of the hydraulically actuated multi-disc brake to reduce the energy loss due to drag between the disks, and to reduce the brake operating oil pressure to reduce the pump driving load. Even so, it contributes to improved fuel efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The drawings show an embodiment of the present invention, wherein 1 is a transmission case, 2,
Reference numeral 3 denotes an input shaft and an output shaft which are rotatably supported in the transmission case 1 in a coaxial butting relationship. The input shaft 2 has an outer end protruding outside the transmission case 1 drivingly connected to an engine (not shown). At the inner end of the input shaft 2, a front planetary gear 4 and a rear planetary gear 5 are arranged coaxially adjacent to each other so that power can be transmitted between the input and output shafts by these planetary gears.

In order to determine the transmission path during this time, that is, the shift speed,
High clutch 6, reverse clutch 7, band brake 8, low one-way clutch 9 as a one-way clutch, forward clutch 10 as a hydraulically actuated multi-plate clutch, forward one-way clutch 11, overrun clutch 13, and a certain hydraulic operation Various friction elements of the low reverse brake 14 as a multiple disc brake are provided.
By the selective operation of these frictional elements, the engine power to the input shaft 2 reaches the output shaft 3 via the planetary gears 4 and 5, during which the speed is shifted at a gear ratio corresponding to the selected shift speed.
The shifting power is input from the output shaft 3 to a differential gear (not shown) via an output gear 14 connected thereto.

Among the various friction elements, the low reverse brake 13 according to the present invention includes a fixed disk 16 fitted to the inner peripheral spline 15 of the transmission case 1 and a rotating disk 17 spline fitted to the outer periphery of the rotating body to be braked. The brake disks are arranged alternately, and a predetermined braking operation is performed by frictionally engaging the disks 16 and 17 with the stroke of the operating piston 18.

The low one-way clutch 9 is disposed adjacent to the low reverse brake 13 in the axial direction and fitted in the transmission case 1, and the forward clutch 10 is mounted on the low reverse brake 13.
It is arranged on the inner circumference of 13.

In the present invention, in order to transfer the working piston 18 of the low reverse brake 13 to the dead space 19 generated between the low one-way clutch 9 and the forward clutch 10 due to the configuration of the transmission gear machine, the working piston 18 is connected to the brake discs 16 and 17. It is arranged between the row one way clutch 9.

Dead space is required when installing the working piston 18.
An annular retainer 20 having a U-shaped cross-section is fitted in the transmission case 1 and disposed inside the transmission case 1, and an operating piston 18 is slidably fitted in the retainer to define a hydraulic chamber 21. By supplying hydraulic pressure to the chamber 21, the working piston 18 moves to the left in the drawing to frictionally engage the discs 16 and 17, and a predetermined braking action can be obtained.

Here, the working piston 18 has an inner peripheral portion of the pressure receiving surface facing the chamber 21,
The pressure receiving area of the working piston 18 is increased by making the diameter smaller so as to overlap the forward clutch 10 when viewed in the axial direction. In this case, the pressure receiving area of the working piston 18 can be increased without changing the outer dimensions of the automatic converter, and the increase in the pressure receiving area enables the number of disks 16 and 17 to be reduced, and the energy loss accompanying the drag between the disks is reduced. Room
By reducing the pressure to 21, the pump driving load can be reduced, and in any case, contributes to the improvement of fuel efficiency.

(Effects of the Invention) By the way, as described above, the hydraulically actuated multiple disc brake of the present invention
Since the working piston 18 is disposed between the one-way clutch 9 of the brake discs 16 and 17, the piston 18 can be located in the dead space 19 between the one-way clutch 9 and the hydraulic working clutch 10.
Is not located at the end of the transmission case 1 which can be reduced in diameter,
The end of the transmission case is not enlarged,
There is no situation in which the working piston of the hydraulic working clutch 10 at the end of the transmission case needs to be reduced in diameter.

Further, according to the present invention, the inner diameter of the pressure receiving surface of the working piston is made small so as to overlap the certain hydraulically actuated multi-plate clutch when viewed in the axial direction, so that the outer dimensions of the automatic transmission are not changed. The pressure receiving area of the working piston can be increased. In this case, it is possible to reduce the number of brake disks of the hydraulically actuated multi-disc brake to reduce the energy loss due to drag between the disks, and to reduce the brake operating oil pressure to reduce the pump driving load. Even so, it contributes to improved fuel efficiency.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a main part of an automatic transmission according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Transmission case 2, ... Input shaft 3 ... Output shaft 4 ... Front planetary gear 5 ... Rear planetary gear 6 ... Hitch latch, 7 ... Reverse clutch 8 ... Band brake 9 ... Low one way clutch (some One-way clutch) 10 Forward clutch (a certain hydraulically actuated multiple disc clutch) 11 Forward forward one-way clutch 12 Overrun clutch 13 Low reverse brake (a certain hydraulically actuated multiple disc brake) 16 Fixed disc (Brake disc) 17 Rotating disc (Brake disc) 18 Working piston 19 Dead space 20 Retainer

Claims (1)

(57) [Claims] 1. A transmission case in which a gear transmission mechanism whose gear position is determined by a selection operation of various friction elements is housed in a transmission case, and a one-way clutch, a hydraulically operated multi-plate brake, and a Automatic transmission in which a plurality of hydraulically actuated multi-plate clutches of the various frictional elements are arranged on an inner periphery of the certain hydraulically actuated multi-plate brake. In the working piston of the certain hydraulically actuated multi-disc brake in the axial direction, disposed between the brake disc of the certain hydraulically actuated multi-disc brake and the certain one-way clutch,
A hydraulically actuated multi-disc brake for an automatic transmission, wherein the inner diameter of the pressure receiving surface of the actuating piston is viewed in the axial direction so as to overlap with the certain hydraulically actuated multi-disc clutch.