JPH11351353A - Torque converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the contact of the clutch facing of a lockup piston plate with a converter cover on the lower speed ratio side where the pressure of a front chamber relatively lowers, and the peeling of a facing material. SOLUTION: This torque converter is provided with a lockup device 26 comprising a front chamber 30 formed between an axially movable lockup piston plate 27 and a converter cover 20 opposed thereto to perform a lockup by releasing the working fluid in the front chamber 30 and releasing the lockup by supplying the working fluid to the front chamber 30. In such a structure, a plurality of ribs 34 are radially formed in a prescribed part for forming the front chamber 30 of the lockup piston plate 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque converter used for a power transmission mechanism of a vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, a torque converter interposed between an engine and a transmission of a vehicle has been widely used. A lock-up device for mechanically connecting the input / output side of the device is provided.

[0003] As shown in FIG.
A pump impeller 2 rotating integrally with a casing (converter cover) 1 connected to an engine crankshaft (not shown), a turbine 5 connected to an input shaft (not shown) of a transmission via a turbine hub 3, Stator 6
And so on.

In the lock-up device 7, a piston plate 10 having a clutch facing 8 attached to a peripheral edge of a front surface is fitted to a turbine hub 3 so as to be movable in an axial direction, and a damper is provided between the piston plate 10 and the turbine hub 3 in a rotational direction. 11 is interposed.

[0005] In the non-lockup state, the working fluid (converter pressure) flows from the input shaft of the transmission to the piston plate 10.
And the clutch facing 8 of the piston plate 10 is maintained in a non-contact state with the converter cover 1.

At the time of lock-up, the piston plate 1
0, the front chamber 12 is opened, working fluid is supplied from around the input shaft of the transmission through the vicinity of the stator 6 and into the converter, and the piston plate 10 advances by the subsequent converter pressure, thereby disengaging the clutch facing 8. By being pressed against converter cover 1, they are connected. At this time, the torque fluctuation of the engine is attenuated by the damper 11 (Japanese Utility Model Laid-Open No. 7-12651).

[0007]

Incidentally, in such a torque converter, the clutch facing 8 of the piston plate 10 is required to improve the lock-up response in order to further improve the fuel efficiency of the vehicle. And the converter cover 1 are set to have a small clearance.
In addition, the pump impeller 2, the turbine 5, and the stator 6
Depending on the combination of elements, the clearance tends to be narrow.

However, if the clearance is reduced, or if the clearance is determined in accordance with the high speed ratio side where the difference between the rotation of the pump impeller 2 and the turbine 5 is small, the clearance exceeds the allowable limit on the low speed ratio side.
The clutch facing 8 of the piston plate 10 may come into contact with the converter cover 1 even though it is not in the lockup state. That is, on the low speed ratio side where the difference between the rotation of the pump impeller 2 and the rotation of the turbine 5 is large, the difference between the pressure in the front chamber 12 of the piston plate 10 and the subsequent converter pressure becomes small. When the facing material comes into contact with the cover 1, the facing material may be peeled off by friction, so that lock-up may not be completely performed.

An object of the present invention is to solve such a problem.

[0010]

According to a first aspect of the present invention, a front chamber is defined between a lock-up piston plate freely movable in an axial direction and a converter cover facing the lock-up piston plate, and a working fluid in the front chamber is defined. In the torque converter having a lock-up device for performing lock-up by opening the lock-up and releasing lock-up by supplying the working fluid to the front chamber, a predetermined portion defining the front chamber of the lock-up piston plate is radially provided. Form a plurality of ribs.

[0011] In a second aspect based on the first aspect, the rib has a cross-sectional shape inclined in a rotation direction of the lock-up piston plate.

[0012] In a third aspect based on the first aspect, the rib is positioned such that the inner peripheral side is located forward of the outer peripheral side in the rotation direction of the lock-up piston plate.

In a fourth aspect based on the first aspect, the rib has an inner peripheral side inclined toward the rotation direction of the lock-up piston plate.

According to a fifth aspect of the present invention, a front chamber is defined between a lock-up piston plate that is freely movable in the axial direction and a converter cover facing the lock-up piston plate, and lock-up is performed by releasing the working fluid in the front chamber. In the torque converter having a lock-up device for releasing lock-up by supplying a working fluid to the front chamber, a plurality of grooves are radially formed in a predetermined portion of the lock-up piston plate that defines the front chamber. .

[0015]

According to the first aspect of the present invention, the pressure in the front chamber between the converter cover and the lock-up piston plate is increased by the rib formed on the lock-up piston plate. Even on a low speed ratio side where the difference in rotation is large and the pressure in the front chamber relatively decreases, the minimum clearance between the clutch facing of the lock-up piston plate and the converter cover can be maintained. Therefore, it is possible to reliably prevent the clutch facing from coming into contact with the converter cover even when not in the lock-up state and the facing material is peeled off by friction, and the clearance can be reduced to improve the lock-up responsiveness.

According to the second aspect, when the clearance between the clutch facing of the lock-up piston plate and the converter cover is small, the pressure in the front chamber can be effectively increased.

According to the third and fourth aspects, the pressure increase in the front chamber can be further increased.

According to the fifth aspect, the distortion of the material due to the welding of the ribs can be reduced, and the strength of the lock-up piston plate can be improved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, 20 is a casing (converter cover) connected to an engine crankshaft (not shown), 21 is a pump impeller that rotates integrally with the converter cover 20, and 22 is a turbine hub 23 via a turbine hub 23. A turbine connected to an input shaft (not shown) of the transmission;
25 is a stator.

The lock-up device 26 faces the inner surface of the converter cover 20 and has a disc-shaped piston plate 2.
7 is fitted to the turbine hub 23 so as to be freely movable in the axial direction,
A clutch facing 28 is attached to a peripheral edge of the front surface of the piston plate 27. A front chamber 30 is defined between the piston plate 27 and the converter cover 20, and a damper 31 that absorbs fluctuations in the rotation direction is interposed between the piston plate 27 and the turbine hub 23.

The intermediate circumferential portion 32 of the piston plate 27
Are formed on the front side to increase the rigidity of the piston plate 27, and the converter cover 20
The inner circumferential portion 33 on the inner surface of the second member is formed in a concave shape.

A plurality of ribs 34 are radially formed on the front surface of the piston plate 27 that defines the front chamber 30. The rib 34 is formed in the convex intermediate circumferential portion 32 of the piston plate 27 in a radial direction with a predetermined width, and at a height not in contact with the converter cover 20.

In this case, the rib 34 may be formed by welding a plate material to the piston plate 27, may be formed on the piston plate 27 by pressing, or may be formed integrally with the piston plate 27 by casting. Is also good.

In the non-lockup state, the working fluid (converter pressure) is supplied from the input shaft of the transmission through the front chamber 30 of the piston plate 27 into the converter.
Further, at the time of lock-up, the front chamber 30 of the piston plate 27 is opened, and the working fluid is supplied into the converter from around the input shaft of the transmission through the vicinity of the stator 25.

With this configuration, the piston is adjusted in accordance with the high speed ratio where the difference between the rotation N ₁ of the pump impeller 21 and the rotation N ₂ of the turbine 22 is small or by the combination of the pump impeller 21, the turbine 22 and the stator 25. Even if the clearance between the clutch facing 28 of the plate 27 and the converter cover 20 is small, the lock-up state is established on the low speed ratio side where the difference between the rotation N ₁ of the pump impeller 21 and the rotation N ₂ of the turbine 22 is large. There is no possibility that the clutch facing 28 comes into contact with the converter cover 20 when there is no clutch facing.

FIGS. 2 and 3 show the pressure distribution applied to both surfaces of the piston plate 27 in the high speed ratio range and the low speed ratio range, respectively.

As shown in FIG. 2, in the high speed ratio region, the left side (rear side) of the piston plate 27 has a pressure distribution of a forced vortex rotating at the rotation speed of the turbine 22, and the piston plate 27
On the right side (front chamber 30 side) is obtained by superimposing the pressure distribution of the forced vortex rotating at an intermediate rotation speed between the turbine 22 and the pump impeller 21 and the pressure loss of the fluid flowing through the clearance between the clutch facing 28 and the converter cover 20. It will be. In this pressure distribution, since the pressure at the clutch facing 28 on the right side of the piston plate 27 is high, the piston plate 27
Is stable. Therefore, even in the case of the present example in which the rib 34 is provided, the pressure distribution and the clearance hardly change.

On the other hand, as shown in FIG. 3, in the low speed ratio range, the difference between the rotation N ₁ of the pump impeller 21 and the rotation N ₂ of the turbine 22 is large, so that the right side of the piston plate 27 (the front chamber 30 side) 3) is relatively weakened (dotted line in FIG. 3), and if the pressure is kept as it is, the clearance may exceed the allowable limit. In this case, however, the fluid rotates at the same rotational speed as the pump impeller 21 at the rib 34. , The pressure increases greatly, and the pressure distribution becomes as shown by the solid line in FIG. Therefore, the clearance does not become narrow, and the piston plate 27 is stabilized with the same clearance as in the high speed ratio region even in the low speed ratio region.

Accordingly, it is possible to secure a high lock-up responsiveness by reducing the clearance, and to prevent the clutch facing 28 from coming into contact with the converter cover 20 even when the lock-up state is not established, and the facing material is separated by friction. Can be reliably prevented, and high reliability can be obtained.

FIG. 4 (corresponding to a section taken along the line AA in FIG. 1) shows a second embodiment, in which a piston plate 27 is provided.
The rib 40 provided on the front surface of the piston plate 27
Is formed so as to have a cross-sectional shape that is inclined toward the rotation direction.

With this configuration, when the clearance between the clutch facing 28 and the converter cover 20 becomes narrow, the leakage flow from the tip 41 side of the rib 40 is reduced, and the front chamber 30 of the piston plate 27 The pressure can be increased effectively.

FIG. 5 shows a third embodiment, in which a rib 50 provided on the front surface of the piston plate 27 is positioned such that the inner peripheral side is located forward of the outer peripheral side in the rotational direction of the piston plate 27. It is formed.

FIG. 6 shows a fourth embodiment, in which a rib 60 provided on the front surface of the piston plate 27 is formed such that its inner peripheral side is inclined toward the rotation direction of the piston plate 27.

According to these, the pressure rise at the ribs 50 and 60 can be further increased. In this case, the ribs 50 according to the third embodiment are formed linearly, and the ribs 60 according to the fourth embodiment are formed as polygonal lines.

FIG. 7 shows a fifth embodiment in which a plurality of grooves 70 are formed radially instead of providing ribs on the front surface of the piston plate 27. The shape, size, and depth of the groove 70 can be variously set.

In this way, it is possible to reduce the distortion of the material when the ribs are welded, and to improve the strength of the piston plate 27.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a torque converter showing an embodiment.

FIG. 2 is a distribution diagram of pressure applied to both surfaces of a piston plate in a high speed ratio range.

FIG. 3 is a pressure distribution diagram applied to both surfaces of a piston plate in a low speed ratio range.

FIG. 4 is a cross-sectional view of a rib according to a second embodiment.

FIG. 5 is a front view of a rib according to a third embodiment.

FIG. 6 is a front view of a rib according to a fourth embodiment.

FIG. 7 is a front view of a groove according to a fifth embodiment.

FIG. 8 is a sectional view of a conventional torque converter.

[Explanation of symbols]

 Reference Signs List 20 casing (converter cover) 21 pump impeller 22 turbine 25 stator 26 lock-up device 27 piston plate 28 clutch facing 30 front chamber 31 damper 32 intermediate circumferential portion 33 intermediate circumferential portion 34 rib 40, 50, 60 rib 70 groove

Claims (5)

[Claims] 1. A front chamber is defined between a lock-up piston plate freely movable in an axial direction and a converter cover facing the lock-up piston plate, and lock-up is performed by opening a working fluid in the front chamber. In a torque converter including a lock-up device that releases lock-up by supplying a working fluid to a chamber, a plurality of ribs are radially formed at a predetermined portion defining a front chamber of the lock-up piston plate. Torque converter. 2. The torque converter according to claim 1, wherein the rib has a cross-sectional shape inclined in a rotation direction of the lock-up piston plate. 3. The torque converter according to claim 1, wherein the rib has an inner peripheral side located forward of an outer peripheral side in a rotation direction of the lock-up piston plate. 4. The torque converter according to claim 1, wherein an inner peripheral side of the rib is inclined toward a rotation direction of a lock-up piston plate. 5. A front chamber is defined between a lock-up piston plate freely movable in the axial direction and a converter cover facing the lock-up piston plate, and lock-up is performed by releasing the working fluid in the front chamber. In a torque converter including a lock-up device that releases lock-up by supplying a working fluid to a chamber, a plurality of grooves are radially formed in a predetermined portion of the lock-up piston plate that defines a front chamber. Torque converter.