JPS6113033A - Speed change gear - Google Patents

Abstract

PURPOSE:To reduce axial dimensions as well as to aim at miniaturization in a speed change gear, by installing a front clutch, cutting off power transmission in time of selecting a forward/backward motion, in position between a hydraulic coupling and an engine. CONSTITUTION:A drive plate 2 is coupled with the end part of a crankshaft 1a of an engine, and this drive plate 2 is solidly locked to the side of a hydraulic coupling cover 3. A pump 5 and a front clutch 7 are shiftably coupled together with each other at peripheral end parts 5a and 7a in an axial direction. The front clutch 7 is made to operate with hydraulic pressure out of a hydraulic coupling 4 so that an operating mechanism for operating the front clutch 7 is no longer required in a separate manner, thus miniaturization is well promotable.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transmission suitable as a transmission for an automobile.

BACKGROUND OF THE INVENTION Conventionally, various transmission devices have been proposed in which a fluid coupling is disposed between a speed change/switching mechanism such as a planetary gear transmission mechanism and an engine.

In this type of transmission, when switching between forward and reverse, it is necessary to cut off the power transmission from the engine to the transmission/switching mechanism, so a clutch is provided inside the transmission/switching mechanism. It is known from the publication No.-94661. However, this not only increases the axial dimension and increases the size of the transmission/switching mechanism itself, but also causes the inertial mass from the turbine side of the fluid coupling to the clutch to directly act on the downstream transmission/switching mechanism when the clutch is engaged or engaged. Therefore, it has the disadvantage of causing an extremely large shock.

Purpose of the Invention The present invention has been made in view of such conventional problems.
The purpose of this is to provide a transmission that is smaller in size by reducing the axial dimension, and that generates less shock when the clutch is engaged or engaged.

Structure of the Invention In order to achieve the above object, the present invention provides a front clutch between the fluid coupling and the engine that cuts off power transmission when switching between forward and reverse directions.

In other words, by installing the front clutch outside the speed change/switching mechanism, the increase in axial dimensions can be kept to a minimum, and since the fluid coupling exists between the front clutch and the speed change/switching mechanism, it is possible to The shock is absorbed by the fluid coupling and is prevented from being transmitted to the transmission/switching mechanism. Additionally, this front clutch can be used not only to cut off power transmission when switching between forward and reverse directions, but also to obtain a completely neutral state.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows an example in which the transmission according to the present invention is used in a front-wheel drive automatic transmission for automobiles.
It is composed of a forward/reverse switching mechanism B, a continuously variable transmission C, a reduction gear train, and a differential E.

First, the configuration of the starting mechanism will be explained according to Figure 2.
A drive plate 2 is coupled to an end of the crankshaft 1a of the engine 1, and the drive plate 2 is integrally fixed to a side surface of a fluid coupling cover 3. Inside the fluid coupling cover 3, a pump 5, a turbine 6, a front clutch 7, a centrifugal lock-up clutch 11, etc. that constitute the fluid coupling 4 are rotatably housed. pump 5
and the front clutch 7 are engaged with each other so as to be movable in the axial direction at their outer peripheral ends 5a and 7a, and the inner peripheral end 7b of the front clutch 7 is connected to the outer periphery of a hub 10 that is integrally fixed to the turbine shaft 9. It is slidably inserted into the surface. Therefore, although the front clutch 7 rotates integrally with the pump 5, it can also move slightly in the axial direction. Above front clutch 7
A friction material 8 is fixed to the side surface of the fluid coupling cover 3, and when this friction material 8 comes into contact with and separates from the inner surface of the fluid coupling cover 3, power is interrupted. On the other hand, a centrifugal lock-up clutch 11 is integrally connected to the turbine 6 via the hub 10 and torsional damper 12. When the rotation speed of the turbine 6 exceeds a predetermined value, the centrifugal lock-up clutch II comes into pressure contact with the inner periphery of the front clutch 7, which rotates integrally with the pump 5, thereby directly connecting the pump 5 and the turbine 6.

The front clutch 7 is operated by the hydraulic pressure of the fluid coupling 4. That is, when switching forward or backward or in a neutral state, oil is pumped from a hydraulic pump (not shown) between the front clutch 7 and the inside of the fluid coupling cover 3 via the oil passage 13, and this oil is pumped into the pump 5.
The oil enters the fluid coupling 4 through the gap between the outer peripheral ends 5a and 7a of the front clutch 7, and is further discharged through the oil FIIiI4. That is, the front clutch 7 is pushed to the left in FIG. 2 by the oil pressure from the oil passage 13, and the front clutch 7 and the fluid coupling cover 3 are separated. Contrary to the above, when oil is supplied from the oil passage 14 and the oil passage 13 side is drained, the oil pressure between the front clutch 7 and the inside of the fluid coupling cover 3 becomes lower than that inside the fluid coupling 4, and the oil pressure at the front The clutch 7 is pushed to the right in FIG. 2, and the front clutch 7 and the fluid coupling cover 3 are coupled.

Note that the present invention is not limited to operating the front clutch 7 with the hydraulic pressure of the fluid coupling 4, but if the front clutch 7 is operated with the hydraulic pressure of the fluid coupling 4 as in the above embodiment, the front clutch 7 is operated. There is no need to separately provide an operating mechanism for this purpose, and the structure can be simplified and miniaturized, and control is also facilitated.

Here, the operation of the starting mechanism having the above configuration will be explained. When the engine rotates, the fluid coupling cover 3 also rotates, and oil sent from the hydraulic pump passes through the oil passage 14 to the fluid coupling 4.
The hydraulic pressure connects the front clutch 7 and the fluid coupling cover 3, and the pump 5 starts rotating. As the pump 5 rotates, the turbine 6 also begins to rotate, and when the rotation speed of the turbine 6 reaches a predetermined value, the lock amplifier clutch 11 and the front clutch 7 are mechanically coupled, and from then on, the engine power from the crankshaft 1a is transferred to the fluid coupling. 4
Drive plate 2゜Fluid joint cover 3 without going through
．． The power is transmitted to the turbine shaft 9 via the front clutch 7 and lock-up clutch 11.

A deceleration/forward/reverse switching mechanism B is provided behind the starting mechanism A. In other words, a gear 15 provided at an end of the turbine shaft 9 meshes with a reduction gear 17 provided at one end of a counter shaft 16 parallel to the turbine shaft 9. Counter axis 1
6 is provided with a spline tooth 18 at the other end, and another counter shaft 19 having spline teeth 20 opposite to the spline tooth 18 is arranged in series with the counter shaft 16. A sleeve 22 having tongue clutch teeth on its inner surface and a reverse gear 23 on its outer surface is spline-engaged with the outer periphery of both spline teeth 18 and 20 so as to be movable in the axial direction by the tongue clutch teeth. The sleeve 22 causes the spline teeth 18.20, ie the countershaft 16.degree. 19, to rotate together. A reduction gear 21 is provided at the other end of the counter shaft 19 having the spline teeth 20, and this reduction gear 21 is constantly meshed with a gear 25 of a drive shaft 24. Therefore, the power of the turbine shaft 9 is transmitted to the drive shaft 24 via the countershaft 16.19, and the direction of rotation of the drive shaft 24 is the same as that of the turbine shaft 9. In other words, the vehicle can be moved forward.

Reference numeral 27 denotes a shift fork that moves the sleeve 22 in the axial direction. When the shift fork 27 is operated rightward in FIG. The outer reverse gear 23 meshes with the idle gear 28. Since this idle gear 28 is always in mesh with the gear 26 of the drive shaft 24, the power of the turbine shaft 9 is converted into reverse rotation and transmitted to the drive shaft 24. In other words, the vehicle can be moved backwards.

As mentioned above, the shift fork 27 causes the sleeve 22 to
When switching forward and backward by moving engine 1,
It is necessary to cut off power transmission from the vehicle to the deceleration/forward/reverse switching mechanism B, and at this time the front clutch 7 is activated. . That is, the hydraulic pressure switching between the oil passage 13 and the oil passage 14 is linked to the operation of the shift fork 27, and the shift fork 27 is stopped at either the left end position (forward) or the right end position (retreat) in FIG. When the shift fork 27 is operated, hydraulic pressure is applied from the oil passage I4 to connect the front clutch 7, and at the same time when the shift fork 27 is operated, oil pressure is applied from the oil passage 13 to disengage the front clutch 7 and power transmission is cut off. Therefore, the shift fork 27 can be operated smoothly when switching between forward and reverse directions, and problems such as gear noise can be eliminated. Furthermore, since there is a fluid coupling 4 between the front clutch 7 and the deceleration/forward/reverse switching mechanism B, when the front clutch 7 is connected again after switching between forward/reverse, the shock is absorbed by the fluid coupling. 4
This prevents a large load from acting on the deceleration/forward/forward switching mechanism B.

Note that the front clutch 7 is used not only when switching between forward and reverse directions, but also to obtain a neutral state. That is, in the conventional transmission, there is no means to obtain a complete neutral state, so there is a problem of creep during idling, but in the present invention, the front clutch 7
By removing this, a complete neutral state can be obtained and creep can be prevented.

A continuously variable transmission C is provided at the rear of the deceleration/forward/reverse switching mechanism B, and this continuously variable transmission C is connected to a driving pulley 30.
, a driven side boob IJ40, and an endless belt 50 wound between these pulleys. The driving side boob IJ30 and the driven side boob IJ40 each include a fixed sheave 31.42 fixed to the shaft 24.41, and movable sheaves 32, 43 that are movable in the axial direction with respect to the shaft 24.41, The actuating means 33 operates the movable sheaves 32, 43 from behind.
By pressing at an angle of 44°, the diameter of the pulley can be varied. The operating means 33, 44 include a hydraulic cylinder controlled by a hydraulic control valve, a centrifugal actuator that displaces the movable sheave by centrifugal force, and a torque cam that generates a sheave thrust commensurate with the input torque. .

In addition, although the said Example showed the case where the continuously variable transmission C was provided in the rear part of the deceleration/forward/reverse switching mechanism B, this order may be reversed.

Effects of the Invention As is clear from the above explanation, according to the present invention, a front clutch is provided between the fluid coupling and the engine to cut off power transmission when switching between forward and backward motions, so the clutch is provided within the speed change/switching mechanism. In addition to being able to reduce the axial dimension compared to the conventional case, the fluid coupling exists between the front clutch and the transmission/switching mechanism, so the shock when the clutch is engaged or disconnected is absorbed by the fluid coupling and is not transmitted to the transmission/switching mechanism. . Additionally, if you disengage the front clutch when idling, you can achieve a completely neutral state and prevent creep.

[Brief explanation of the drawing]

FIG. 1 is a skeleton diagram of an example of a transmission device according to the present invention, and FIG. 2 is a detailed sectional view of its starting mechanism. A...Starting mechanism, B...Deceleration/forward/backward switching mechanism, C
... Continuously variable transmission, 1... Engine, 4... Fluid coupling, 7... Front clutch. Applicant Daihatsu Motor Co., Ltd. Agent Patent Attorney Hidetaka Tsutsui Figure 1, Figure 2, Figure 2

Claims (1)

[Claims] (1) A transmission device in which a fluid coupling is disposed between a gear shift/switching mechanism and an engine, characterized in that a front clutch is provided between the fluid coupling and the engine to cut off power transmission when switching between forward and reverse directions. gearbox.