JPH04300448A - Power transmission device for vehicle - Google Patents

Abstract

PURPOSE:To facilitate control of a clutch under a slipping condition, which clutch connects or disconnects a stepless transmission to an engine output shaft. CONSTITUTION:A power transmission device 1 has first and second power transmission passages for transmitting an engine output to front wheels. The first power transmission passage 3 is connected to a turbine shaft 5b of a torque converter 5, while a decelerator 7 is arranged on the first power transmission passage 3. The second power transmission passage 4 is connected to an engine output shaft 2b through a clutch 8, while a V belt stepless transmission 9 is arranged on the second power transmission passage 4. An effective diameter of an input pulley 90 of the V belt stepless transmission 9 is varied based on a hydraulic pressure in an operation oil chamber 94. The clutch 8 is arranged inside the operation oil chamber 94. A hydraulic pressure supplied to the operation oil chamber 9 is not changed largely by the operation condition, for instance, as the lock-up clutch in the torque converter, so that the clutch 8 is easily controlled under a slipping condition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission system for a vehicle, and more particularly to one equipped with a continuously variable transmission.

0002

[Prior Art] As a power transmission device for a vehicle, a power transmission path for transmitting engine output to drive wheels is divided into a first path and a second path.
When the first route is selected, the engine output is transmitted to the drive wheels via the torque converter and the reduction gear.
(continuously variable transmission mode), and when the second route is selected, the engine output is transmitted to the drive wheels via a continuously variable transmission (continuously variable transmission mode).

According to this type of device, when the first path is selected, the torque increasing function of the torque converter can be utilized to improve, for example, starting acceleration. On the other hand, when the second route is selected, it becomes possible to set an appropriate gear ratio according to the driving state without causing a shift shock under the continuously variable transmission.

[0004] Furthermore, since the torque converter mode and the continuously variable transmission mode can be adopted in this way, the torque increased by the torque converter is not input to the continuously variable transmission. It has the advantage that the capacity can be made small.

Specific examples of such devices include, for example, Japanese Patent Application Laid-Open No. 176862/1986 or Japanese Patent Application Laid-Open No. 2-24/1999.
As seen in Japanese Patent No. 0444, the first path is connected to the turbine shaft of the torque converter, and a reduction gear is disposed on this first path, while the second path is connected to the turbine shaft of the torque converter. A continuously variable transmission was connected to the engine output shaft via a clutch and disposed on this second path. and,
In these conventional examples, the clutch was constructed as a lock-up clutch within a torque converter.

Therefore, when the lock-up clutch is released, the engine output is transmitted to the drive wheels via the first path (torque converter mode). On the other hand, when the lock-up clutch is engaged, the engine output is transmitted to the drive wheels via the second path (continuously variable transmission mode).

[0007]

[Problems to be Solved by the Invention] By the way, the above-mentioned clutch is not released or engaged all at once. In other words, in order to prevent the occurrence of shock due to the change in the power transmission mode between the torque converter mode and the continuously variable transmission mode, the clutch should be adjusted appropriately when transitioning from one mode to the other mode. It is necessary to change the power transmission mode while sliding it.

[0008] However, the lock-up clutch
It is operated by the differential pressure inside the torque converter, and since the oil pressure inside this torque converter changes depending on the load and rotation speed, it is necessary to appropriately slip the lock-up clutch, that is, to prevent the lock-up clutch from slipping. There is a problem in that it is difficult to adjust the rate to a target value depending on the operating state. Of course, if this slip rate is not properly controlled, the problem of shock generation occurs.

[0009] Accordingly, the present invention facilitates appropriate control of the clutch slip state that occurs when the power transmission mode is changed between the torque converter mode and the continuously variable transmission mode. The purpose of the present invention is to provide a power transmission device for a vehicle.

0010

[Means for Solving the Problems] In order to achieve this technical problem, the present invention has a first power transmission path and a second power transmission path for transmitting the engine output to the driving wheels, and the first power transmission path The power transmission path is connected to the turbine shaft of the torque converter, a reduction gear is disposed on the first power transmission path, and the second power transmission path is connected to the engine output shaft via a clutch. Assuming a power transmission device for a vehicle in which a continuously variable transmission is disposed in the second power transmission path,

0
[011] The clutch is arranged to be interposed in an input element of the continuously variable transmission.

0012

[Operation] According to the above structure, since the clutch is disposed outside the torque converter whose oil pressure tends to fluctuate depending on the operating state, it becomes easy to control the slip state of the clutch.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings. Figure 1 shows a power transmission device 1 mounted on a vehicle.
This shows that. First, an overview of this power transmission device 1 will be explained. In this vehicle, an engine 2 is mounted in the front portion (front) of the vehicle. The engine 2 is an in-line four-cylinder engine with four cylinders 2a arranged in series, and is mounted on the vehicle with the output shaft 2b facing in the vehicle width direction, so that the output of the engine 2 is transmitted to the front wheels. It has become.

That is, in a vehicle equipped with this power transmission device 1, the engine 2 is installed horizontally, and its drive system is as follows.
It is considered a so-called FF car.

As shown in FIG. 2, the power transmission device 1 has a first path 3 and a second path 4 as power transmission paths for transmitting the output of the engine 2 to the front wheels. Disposed on the path 3 are a torque converter 5, a forward/reverse switching device 6 for switching between forward and backward movement, and a speed reduction device 7. On the other hand, a clutch 8 and a continuously variable transmission 9 are disposed on the second path 4, and by connecting and disconnecting the clutch 8, basically the first path 3 and the second path 4 are connected. The switching is now performed.

That is, when the clutch 8 is released, the first path 3 is selected and the engine output is transmitted to the front wheels via the torque converter 5 etc. (torque converter mode). On the other hand, when the clutch 8 is engaged, the second path 4 is selected and the engine output is transmitted to the front wheels via the continuously variable transmission 9 (continuously variable transmission mode).
.

Based on the above premise, the mechanical structure of the power transmission device 1 will be explained in detail with reference to FIG. Torque Converter 5 The torque converter 5 is arranged on the same axis as the output shaft 1b of the engine 1, and the input shaft 5a of the torque converter 5 is coupled to the engine output shaft 1b.

The torque converter 5 has an input shaft 5
a is integrated with the pump cover 50, and this pump cover
50, a pump impeller 51, a turbine liner 5
2. A stator 53 is arranged and filled with hydraulic oil.

The pump impeller 51 is connected to the pump cover 5.
The turbine liner 52 is disposed opposite the pump impeller 51. Further, the stator 53 is disposed between the pump impeller 51 and the turbine liner 52, and with respect to the turbine liner 52,
A turbine shaft 5b, which is a hollow shaft, is coupled thereto.

The stator 53 is connected to a second hollow shaft 5 disposed coaxially with the turbine shaft 5b.
5 through a one-way clutch 56, and this second hollow shaft 55 is integrated with the casing 10.

A second output shaft 5C shown in FIG. 1 is connected to the turbine shaft 5.
b, and the front end thereof is located at the pump bar 50.
is combined with That is, the second output shaft 5c
is directly connected to the engine output shaft 2b, and the rear end of the second output shaft 5c is connected to the continuously variable transmission 9 via the clutch 8.

Continuously variable transmission 9 The continuously variable transmission 9 is composed of a V-belt type transmission.
The input pulley 90 of the belt type transmission 9 is connected to its rotating shaft 9a.
is arranged on the same axis as the engine output shaft 2b, a plate 91 is fixed to one end of this rotating shaft 9a, and the clutch 8 is connected between the plate 91 and the second output shaft 5c. is provided.

As is known, the V-belt type transmission 9 has an output pulley 92 in addition to the input pulley 90, and the output shaft 9b of the output pulley 92 is connected to the input shaft 9a. arranged in parallel.

The input pulley 90 is composed of a fixed disc 90a and a movable disc 90b, and the output pulley 92 is composed of a fixed disc 92a and a movable disc 92b. 92a are fixed to the input shaft 9a and output shaft 9b, respectively. On the other hand, the movable disks 90b and 92b are slidable in the axial direction with respect to the input shaft 9a and the output shaft 9b, respectively, and the input pulley 90 and the output pulley 92 are The effective diameter can be changed.

The input pulley 90 and the output pulley 92 each have a V-shaped groove formed by a pair of disks 90a and 90b, or a V-shaped groove formed by disks 92a and 92b. There is. A belt 93 having a V-shaped cross section is stretched between these input pulleys 90 and output pulleys 92, and by changing the effective diameters of the input pulleys 90 and output pulleys 92, The speed ratio of the output pulley 92 to the pulley 90 can be changed steplessly.

Reducer 7 The reducer 7 is composed of two gear trains 71 and 72, a first gear train and a second gear train 72, and these gear trains 71 and 72 are connected to a torque converter 5.
and the continuously variable transmission 9.

The first gear train 71 is for reverse use and is composed of two spur gears 71a and 71b, one spur gear 71a being connected to the turbine shaft 5b via the clutch 61.
, and another gear 71b is fixed to the output shaft 9b.

The second gear train 72 is for forward movement, and has a counter gear 7 between two spur gears 72a and 72b.
3 is interposed, one spur gear 72a is connected to the turbine shaft 5b via the clutch 62, and the other spur gear 72a is connected to the turbine shaft 5b via the clutch 62.
b is fixed to the output shaft 9b.

Forward/Reverse Switching Device 6 The forward/reverse switching device 6 is composed of the clutches 61 and 62 mentioned above. That is, the clutch 61 is used as a reverse clutch (for backward movement), and the clutch 62 is used as a forward clutch (for forward movement).

The end of the output shaft 9b on the engine side is connected to a front wheel drive shaft 12 via a gear train 10 and a differential gear 11.

Control of the power transmission device 1 (1) Reverse (torque converter) Both the clutch 8 and the forward clutch 62 are released, and the reverse clutch 61 is engaged.

As a result, engine output is transmitted to the front wheels via the torque converter 5 and the reverse gear train 71.

(2) Neutral All of the clutches 8, 61, and 62 are released.

(3) Different controls are performed between forward start and low-speed operation, and between medium-speed or high-speed operation.

(2) During start-up and low-speed operation (torque converter mode) Both the clutch 8 and reverse clutch 61 are released, and the forward clutch 62 is engaged.

Thereby, engine output is transmitted to the front wheels via the torque converter 5 and the forward gear train 72.

(2) During high-speed operation (continuously variable transmission mode), both the reverse clutch 61 and the forward clutch 62 are released, and the clutch 8 is engaged.

As a result, the engine output is directly input to the continuously variable transmission 9, and from this continuously variable transmission 9 to the output shaft 9b.
is transmitted to the front wheels.

Engagement or Release Control of Clutch 8 The clutch 8 is operated by hydraulic pressure, and this hydraulic pressure is adjusted by a hydraulic circuit (not shown). When the clutch 8 is engaged or disengaged, slip control of the clutch 8 is performed, and a so-called half-clutch state of the clutch 8 is formed so that the slip rate of the clutch 8 becomes a target value.

FIGS. 3 and 4 show a second embodiment. In this embodiment, the same elements as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted, and only the characteristic portions of this embodiment will be explained below.

In this embodiment, the clutch 8 is connected to the hydraulic oil chamber 9 of the input pulley 90 in the V-belt type transmission 9.
It is located within 4.

FIG. 4 shows details of the V-belt type transmission 9. The V-belt type transmission 9 has two hydraulic oil chambers 94.
and 95, one hydraulic oil chamber 94 is used for the input pulley 90, and the other hydraulic oil chamber 95 is used for the output pulley 92.

The hydraulic oil chamber 95 for the output pulley 92 consists of a plate 9b fixed to the output shaft 9b and a movable disc 92b.
Hydraulic pressure is supplied to this hydraulic oil chamber 95 through a passage 96 formed inside the output shaft 9b and the movable disk 92.

The hydraulic oil chamber 94 for the input pulley 90 is defined by two plates 97 and 98 that are spaced apart in the axial direction, and the plate 97 on the movable disk 90b side is connected to the input shaft 9a. It is designed to be able to slide in the axial direction against other players.
98 is fixed to the input shaft 9a.

The movable plate 97 is divided into an inner plate 97a and an outer plate 97b at a radially intermediate portion, and the clutch 8 is disposed between the outer end of the inner plate 97a and the movable disk 90b. It has been intervened. On the other hand, the inner end of the outer plate 97b is fixed to the movable disk 90b.

The clutch 8 is engaged by the pressing force of a free piston 15, and the free piston 15 faces the clutch 8 and connects the movable disk 90b and the diameter of the inner plate 97a. The clutch 8 is in sliding contact with the intermediate portion in the direction, and is biased in a direction away from the clutch 8 by a spring 16.

Hydraulic pressure is supplied to the input pulley hydraulic oil chamber 94 through a passage 99 formed in the input shaft 9a, and when the oil pressure is low, only the free piston 15 moves in the direction in which the clutch 8 is engaged. (leftward movement in Figure 4).

The slip control of the clutch 8 described above is performed by adjusting the oil pressure in the hydraulic oil chamber 94 under a low oil pressure state.

When the hydraulic pressure in the hydraulic oil chamber 94 is brought to a high pressure state, the movable disk 90b moves to the left together with the movable plate 97, and the effective diameter of the input pulley 90 is reduced.

According to this embodiment, since the clutch 8 is disposed inside the input pulley hydraulic oil chamber 94 that originally exists, the length of the device 1 in the axial direction can be shortened. This makes it possible to provide a power transmission device suitable for FF vehicles.

[0051]

As is clear from the above description, according to the present invention, clutch slip control required for power transmission path switching can be facilitated.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a block diagram showing the configuration of the first embodiment.

FIG. 3 is a configuration diagram of a second embodiment.

FIG. 4 is a longitudinal sectional view of the V-belt continuously variable transmission applied to the second embodiment.

[Explanation of symbols]

1 Power transmission device 2 Engine 2b Engine output shaft 3 First path (torque converter mode) 4
Second path (continuously variable transmission mode) 5 Torque converter 5b Turbine shaft 7 Reduction device 8 Clutch 9 V-belt type continuously variable transmission 90 Input pulley 92 Output pulley 93 V-belt 94 Input pulley Hydraulic oil chamber for

Claims (3)

[Claims] Claim 1: A first transmitter that transmits engine output to drive wheels.
, has a second power transmission path, the first power transmission path is coupled to the turbine shaft of the torque converter, a reducer is disposed on the first power transmission path, and the second power transmission path is connected to the turbine shaft of the torque converter. In a power transmission device for a vehicle in which a continuously variable transmission is disposed in the second power transmission path, the second power transmission path is coupled to the engine output shaft via a clutch, and the second power transmission path is coupled to the engine output shaft through a clutch. A power transmission device for a vehicle, characterized in that the device is interposed in an input element. 2. In claim 1, the continuously variable transmission includes an input pulley having a variable effective diameter, an output pulley having a variable effective diameter, and the input pulley and the output pulley. A V-belt type continuously variable transmission is provided with a V-shaped belt stretched over a pulley, and the V-belt type continuously variable transmission has a V-shaped belt stretched between the input shaft and the input pulley. The one that is equipped with a clutch. 3. The apparatus according to claim 2, wherein the clutch is disposed within a hydraulic oil chamber of the input pulley.