JP2008190561A - Torque converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the durability of a friction material for a lock-up clutch. <P>SOLUTION: This torque converter comprises a cover shell 6 to be rotated integrally with the output shaft of an engine, an impeller 2 to be rotated integrally with the cover shell 6, a turbine 3 arranged in the cover shell 6 and having a rotating shaft coaxial with the rotating shaft of the cover shell 6, a lock-up clutch piston 5 provided on the inner face side of the cover shell 6 so as to be rotated integrally with the output shaft slidably in the axial direction, and engaging means 10, 11 for making the lock-up clutch piston 5 in friction engagement with the cover shell 6. The engaging means 10, 11 are a slip friction material 10 which is arranged between the lock-up clutch piston 5 near its outer peripheral edge and the inner face of the cover shell 6, and a fastening friction material 11 which is arranged on the inner periphery side of the slip friction material 10, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lock-up clutch mechanism for a torque converter.

  As a mechanism to improve the output transmission efficiency from the engine to the output shaft, a disk-like piston is attached to the turbine runner provided on the output shaft of the torque converter, and this piston is pressed against the cover shell provided on the input shaft by hydraulic pressure. A lockup mechanism is known in which an output shaft and an input shaft are fastened by a frictional force generated at this time. Generally, a friction material is stretched on the piston in order to stably generate the frictional force.

  And in recent years, in order to improve fuel economy performance and output, so-called slip that uses a state in which the friction material slides with respect to the cover shell (slip state), which occurs during transition between the non-fastened state and the fastened state. Control is taking place.

  However, when slip control is executed, frictional heat is generated between the friction material and the cover shell, and if the friction material temperature rises excessively due to this frictional heat, problems such as accelerated wear of the friction material and a decrease in fastening force during fastening, etc. Occurs.

Therefore, there is a patent on a technical means that prevents frictional heat from rising by providing a groove in the friction material and flowing frictional oil around the contact area between the friction material and the cover shell to remove frictional heat. It is disclosed in Document 1.
Japanese Patent Laid-Open No. 3-209045

  However, in the technique described in Patent Document 1, in order to secure the fastening force at the time of fastening, it is necessary to secure the contact area between the friction material and the cover shell, so the size of the groove for flowing hydraulic oil Is limited. For this reason, there is a problem that a large amount of hydraulic oil cannot be flowed and the temperature of the friction material rises in a short time during the slip control. When the friction material is used in a state deviating from the optimum temperature, problems such as a decrease in friction force and acceleration of wear occur.

  That is, the technique described in Patent Document 1 has a problem that the durability of the friction material is low, and as a result, the time during which slip control is possible is shortened.

  Accordingly, an object of the present invention is to improve the durability of the friction material.

  A torque converter according to the present invention includes a cover shell that rotates integrally with an output shaft of an engine, an impeller that rotates integrally with the cover shell, and a rotation shaft that is disposed within the cover shell and is coaxial with the rotation shaft of the cover shell. A turbine, a lockup clutch piston which is provided on the inner surface side of the cover shell and rotates integrally with the output shaft so as to freely slide in the axial direction, and a friction engagement between the lockup clutch piston and the cover shell. A slip friction material disposed between the vicinity of the outer peripheral edge of the lockup clutch piston and the inner surface of the cover shell opposed to the lockup clutch piston, and an inner portion of the slip friction material. And a fastening friction material disposed on the circumferential side.

  According to the present invention, since two types of friction materials, that is, a slipping friction material and a fastening friction material, are provided, it is possible to obtain a friction material having characteristics suitable for a slip state and a fastening state, respectively. Furthermore, in general, the lock-up clutch piston has a characteristic that the outer peripheral side is inclined closer to the cover shell than the inner peripheral side during slip control, and the inner peripheral side is inclined closer to the cover shell than the outer peripheral side when engaged, Since the slip friction material is arranged on the outer peripheral side and the fastening friction material is arranged on the inner peripheral side, the slip friction material mainly contacts the cover shell during slip control, and the fastening friction material contacts the cover shell during fastening. It will be.

  As described above, the function required at the time of slip control and the function required at the time of fastening are shared by two types of friction materials, and the friction material for slip and the friction material for fastening can be used under appropriate conditions. Compared with the case of one type of friction material, the durability of the friction material is improved.

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

  FIG. 1 is a schematic diagram of a torque converter 1 to which an embodiment of the present invention is applied. 2 is an impeller, 3 is a turbine, 4 is a stator, 5 is a lock-up clutch piston, 6 is a cover shell, 7 is a one-way clutch, 10 is a friction material for slipping, 11 is a friction material for fastening, and 17 is an output shaft of the engine is there. The impeller 2 is welded to the cover shell 6, and a fluid chamber of the torque converter 10 is formed by both. The cover shell 6 is connected to an output shaft 17 of the engine via a nut 9 welded thereto, a drive plate (not shown), and bolts.

  The lock-up clutch piston 5 is disposed between the turbine 3 and the cover shell 6, and an inner diameter portion thereof is supported by the shaft portion of the turbine hub 16 so as to be movable in the axial direction. Further, a damper 8 is provided at the upper end of the side surface of the turbine 3 side of the lockup clutch piston 5 for attenuating fluctuations in transmission torque from the engine when the lockup clutch is engaged.

  A fastening friction material 11 is affixed to a side surface (outer surface) on the cover shell 6 side, and a portion (inner surface) facing the outer surface of the lockup clutch piston 5 on the outer peripheral side from the fastening friction material 11 of the cover shell 6. The slip friction material 10 is affixed.

  The lockup clutch piston 5 divides the fluid chamber of the torque converter 10 into a release chamber 12 on the cover shell 6 side and an apply chamber 13 on the turbine 3 side. Further, a plurality of first hydraulic oil holes 14 as communication holes for communicating the release chamber 12 and the apply chamber 13 are provided on the circumference above the friction material 11 for fastening of the lockup clutch piston 5, A plurality of second hydraulic oil holes 15 are provided at a position of ½ or less of the radius of the piston 5.

  By attaching the slipping friction material 10 and the fastening friction material 11 to the cover shell 6 and the lockup clutch piston 5 as described above, the heat of the slipping friction material 10 is transferred to the cover shell 6 in a slip state to be described later. Since the heat of the friction material 11 for fastening is radiated to the lockup clutch piston 5 respectively, higher heat radiation is obtained as compared with the case where heat is radiated only to either the cover shell 6 or the lockup clutch piston 5. Can do.

  Here, the slipping friction material 10 will be described with reference to FIG. FIG. 2 is a view of the periphery of the slip friction material 10 of the cover shell 6 as viewed from the inner surface side. As shown in the figure, the slip friction material 11 is provided with a plurality of grooves 10a as communication grooves that connect the outer peripheral side and the inner peripheral side. The depth of the groove 10a is set such that the outer peripheral side and the inner peripheral side can be maintained in communication with each other even when the slipping friction material 10 is pressed against the lockup clutch piston 5 in a slip state and a fastening state, which will be described later. Further, the slipping friction material 10 is thicker than the fastening friction material 11 and is formed of a soft material.

  Next, the operation of the lockup mechanism of the torque converter 1 configured as described above will be described with reference to FIG. FIG. 3 is an enlarged view of the periphery of the slipping friction material 10 and the fastening friction material 11 of FIG. 1, and (a) to (c) represent a lock-up release state, a slip state, and a fastening state, respectively.

  In the unlocked state, as shown in FIG. 3A, the slipping friction material 10 and the fastening friction material 11 are separated from the inner surface of the cover shell 6 and the outer surface of the lockup clutch piston 5, respectively. At this time, the hydraulic oil flows in the release chamber 12 from the inner peripheral side toward the outer peripheral side.

  When locking up, hydraulic oil is discharged from the release chamber 12 toward the turbine hub 16, and the lockup clutch piston 5 is pressed against the inner surface of the cover shell 6. At this time, the lock-up clutch piston 5 is inclined as shown in FIG. 3B, and the outer peripheral side moves to the cover shell 6 side earlier than the inner peripheral side, so that the slip friction material 10 is the lock-up clutch piston. 5, but the fastening friction material 11 is not in contact with the inner surface of the cover shell 6. At this time, the lock-up clutch piston 5 slides with respect to the cover shell 6 due to the relationship between the friction coefficient of the slip friction material 10 and the force pressing the lock-up clutch piston 5 against the cover shell 6. This state is referred to as a slip state.

  In the slip state, the hydraulic oil in the apply chamber 13 flows into the release chamber 12 from between the outer periphery of the lockup clutch piston 5 and the cover shell 6. The inflowing hydraulic oil passes through the groove 10a and branches into a flow from the space between the fastening friction material 11 and the cover shell 6 toward the turbine hub 16 and a flow from the first hydraulic oil hole 14 to the apply chamber 13. . Thus, by providing the groove 10a and allowing the hydraulic oil to flow through the groove 10a even in the slip state, the frictional heat generated between the slipping friction material 10 and the lockup clutch piston 5 can be released. . As a result, it is possible to prevent the temperature from rising immediately after the slip state is set, so that the time during which so-called slip control can be performed can be extended.

  When the hydraulic oil is further discharged from the slip state, the inner peripheral side of the lockup clutch piston 5 also moves to the cover shell 6 side as shown in FIG. 3C, and the fastening friction material 11 and the inner surface of the cover shell 6 are moved. And come into contact with each other. At this time, the fastening friction material 11 is pressed against the cover shell 6, and the communication between the outer peripheral side and the inner peripheral side of the fastening friction material 11 is blocked, but from the apply chamber 13 through the second hydraulic oil hole 15. Since the hydraulic fluid flows into the release chamber 12, high temperature hydraulic fluid can be prevented from staying in the apply chamber 13.

  The fastening friction material 11 may be provided with a groove similar to the groove 10a of the slipping friction material 10 to ensure the flow of hydraulic oil from the apply chamber 13 to the release chamber 12 during fastening. However, since it is necessary to ensure the contact area at the time of fastening in order to secure the fastening force, the number of grooves is made smaller than that of the grooves 10a of the slip friction material 10.

As described above, the following effects can be obtained in the present embodiment.
(1) For slipping, a friction material for frictionally engaging the lockup clutch piston 5 and the cover shell 6 is disposed between the vicinity of the outer peripheral edge of the lockup clutch piston 5 and the inner surface of the cover shell 6 facing the friction material. Since the friction material 10 and the fastening friction material 11 disposed on the inner peripheral side of the slip friction material 10 are configured, each friction material can be used under suitable conditions, and the durability of the friction material is improved. Can be made.
(2) Since the slipping friction material 10 is formed of a softer material than the fastening friction material 11, the occurrence of judder during slip control can be prevented.
(3) Since the slipping friction material 10 is thicker than the fastening friction material 11, the fastening friction material 11 is more securely attached to the cover shell 6 when the lock-up clutch piston 5 approaches the cover shell 6. Prior to contact, the lock-up clutch piston 5 is contacted.
(4) The slipping friction material 10 is provided in a portion of the inner surface of the cover shell 6 facing the outer periphery of the lockup clutch piston 5, and the fastening friction material 11 is facing the slipping friction material 10 of the lockup clutch piston 5. The frictional heat generated from the slipping friction material 10 is directed to the lockup clutch piston 5, and the frictional heat generated from the fastening frictional material 11 from the slipping state to the fastening state is directed to the cover shell 6. , Each of which is dissipated. Thereby, compared with the case where heat is radiated only to either one of the lockup clutch piston 5 or the cover shell 6, heat dissipation can be improved.
(5) The slipping friction material 10 includes a groove 10 a that communicates the outer peripheral side and the inner peripheral side of the slipping friction material 10, and the lockup clutch piston 5 is a hydraulic fluid that communicates the release chamber 12 and the apply chamber 13. Since the hole 14 is provided, the hydraulic oil that has passed through the groove 10 a flows into the apply chamber 13 through the hydraulic oil hole 14 even in the slip state. That is, since the heat generated in the slip friction material 10 can be removed by the hydraulic oil, the temperature rise during the slip control can be suppressed, and the time during which the slip control can be performed can be extended.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

It is sectional drawing of the torque converter to which this embodiment is applied. It is the figure which looked at a part of friction material for slips from the axial direction of the output shaft. (A)-(c) is a figure showing the relationship between the lockup clutch piston and a cover shell in a lockup clutch release state, a slip state, and a fastening state, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque converter 2 Impeller 3 Turbine 4 Stator 5 Lockup clutch piston 6 Cover shell 7 One-way clutch 8 Damper 9 Nut 10 Friction material for slip 11 Friction material for fastening

Claims (6)

A cover shell that rotates integrally with the engine output shaft;
An impeller that rotates integrally with the cover shell;
A turbine disposed within the cover shell and having a rotational axis coaxial with the rotational axis of the cover shell;
A lock-up clutch piston that is provided on the inner surface side of the cover shell and rotates integrally with the output shaft so as to freely slide in the axial direction;
Engagement means for frictionally engaging the lock-up clutch piston and the cover shell,
The engaging means includes a slip friction material disposed between the vicinity of the outer peripheral edge of the lock-up clutch piston and the inner surface of the cover shell opposed thereto.
A torque converter comprising: a fastening friction material disposed on an inner peripheral side of the slip friction material.   The torque converter according to claim 1, wherein the slip friction material is formed of a softer material than the fastening friction material.   The torque converter according to claim 1 or 2, wherein the slip friction material is thicker in the axial direction of the output shaft than the fastening friction material. The slip friction material is provided on a portion of the inner surface of the cover shell facing the outer periphery of the lockup clutch piston,
The torque converter according to any one of claims 1 to 3, wherein the fastening friction material is provided on an inner peripheral side of a portion of the lockup clutch piston facing the slip friction material. The slip friction material includes a communication groove that communicates the outer peripheral side and the inner peripheral side of the slip friction material,
The lockup clutch piston includes a portion of the oil chamber formed between the cover shell and the lockup clutch piston between the slip friction material and the fastening friction material, and an oil chamber on the turbine side. The torque converter according to any one of claims 1 to 4, further comprising a communication hole that communicates with each other. The fastening friction material includes a communication groove that communicates the outer peripheral side and the inner peripheral side of the fastening friction material,
6. The torque converter according to claim 5, wherein the number of communication grooves of the fastening friction material is smaller than the number of communication grooves of the slip friction material.

Images