JP2009168146A - Torque converter equipped with lock-up mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque converter equipped with a lock-up mechanism which can be effectively cooled with a necessary fastening capacity ensured. <P>SOLUTION: There is provided a torque converter equipped with a lock-up mechanism capable of forming a directly coupled state by means of a friction clutch which couples an input shaft to which torque is input from an engine and an output shaft coupled to wheels to each other. In the torque converter, the above clutch includes a friction material 30A (30B) on a surface engaging with or disengaging from a member opposed to the friction clutch. The above friction member is approximately annular relatively to the rotary center CP of the friction clutch and includes a plurality of grooves SL which allow a fluid to get in and out between a central side and outside of the friction member and is provided along its circumference. Further, the grooves SL is set so as to vary in width in incremental steps in its radial direction RD and get wider in their outward directions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a torque converter incorporated in an automatic transmission mounted on a vehicle. More specifically, the present invention relates to a vehicle torque converter including a lockup mechanism that directly connects an input shaft and an output shaft.

  In recent years, torque converters equipped with a lock-up mechanism have been adopted to improve fuel efficiency. A torque converter is a type of fluid clutch that transmits engine torque to a transmission via a fluid (generally oil). The torque converter uses oil to transmit engine torque, so it can achieve smooth vehicle travel. However, on the other hand, there have been indications of drawbacks such as fuel consumption deterioration due to energy loss caused by fluid slip. Therefore, recently, torque converters equipped with a lock-up mechanism that can suppress slip as required have been widely adopted.

  A typical lockup mechanism includes a friction clutch (lockup clutch). When the vehicle speed exceeds a predetermined speed, the flow of fluid in the torque converter changes, and the friction surface of the friction clutch is pressed against the opposing member. Thus, the lockup mechanism directly connects the input shaft from the engine and the output shaft connected to the wheels. When the lock-up mechanism is provided, the influence of fluid slip can be suppressed, so that the fuel efficiency of the vehicle can be improved.

  The friction clutch, which is the main element of the lockup mechanism, moves within a predetermined range to form a released state and an engaged state (directly connected state). Between the released state and the fastened state, a slip state is formed in which the friction surface rotates while sliding relatively with a member facing the friction surface (generally a cover of the torque converter) in order to alleviate the impact during direct connection. Is done. In recent years, the number of scenes in which the lockup mechanism is activated from the low speed of the vehicle and the friction clutch is in a slip state is increasing. When the friction clutch is in a slip state, a frictional force is generated on the friction surface and the converter cover. If this state continues for a long time, excessive frictional heat is generated and heat is accumulated, so that the peripheral portion becomes high temperature. This causes a problem of excessive temperature rise in the peripheral portion, for example, a problem of oil deterioration in the torque converter. Therefore, there has been a proposal for a lockup mechanism incorporating a cooling mechanism for removing frictional heat.

For example, since the torque converter disclosed in Patent Document 1 controls the slip state of the friction clutch, the pressure difference for operating the friction clutch is maintained almost constant, and at the same time, the flow rate of fluid (oil) supplied to the friction surface is controlled. A hydraulic control mechanism to be changed is provided. Specifically, a plurality of grooves (oil grooves) through which oil passes are formed in the friction material of the friction clutch as a hydraulic control mechanism. Thus, by installing the groove part through which oil flows in the friction surface, the heat dissipation amount can be increased and the friction surface can be cooled.
JP-A-7-180768

  Patent Document 1 exemplifies a structure that promotes cooling by arranging a large number of grooves in a friction clutch. Such a structure is preferable from the viewpoint of reliably cooling the periphery of the lockup mechanism. However, when a structure having a large number of grooves is provided in this way, the actual contact surface is reduced by an oil film generated by the wedge pressure from the edge. As a result, there is a problem that when the slip state occurs, the friction coefficient is unexpectedly reduced and a sufficient fastening capacity (lock-up capacity) cannot be secured.

  Accordingly, an object of the present invention is to solve the above-described conventional problems and to propose a torque converter including a lockup mechanism capable of efficient cooling while ensuring a necessary fastening capacity.

For the above purpose, the torque converter with a lock-up mechanism according to the present invention is
A lock-up mechanism capable of forming a direct connection state by a friction clutch that connects an input shaft from an engine and an output shaft connected to a wheel;
The friction clutch has a friction material on a surface that is in contact with and separated from an opposing member;
The friction material has a ring shape with respect to the rotation center of the friction clutch, and has a plurality of grooves along the circumferential direction that allow fluid to enter and exit between the center side and the outside. ,
Further, the groove portion is characterized in that its width changes stepwise in the radial direction and is set to be wider as it becomes the outer side.

  According to the torque converter with a lock-up mechanism of the present invention, the width of the outer groove is sufficiently widened to ensure a cooling action, and the width of the inner groove is narrowed to maintain the minimum friction coefficient and increase the fastening capacity. Secure. Therefore, according to the present invention, it is possible to satisfy both requirements that have been difficult in the past.

An example as an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a main configuration of a torque converter with a lockup mechanism according to an embodiment of the present invention. The torque converter 1 with a lockup mechanism includes a pump impeller 2, a turbine runner 3, a stator 4, and a lockup piston 5. The pump impeller 2 is welded to the converter cover 6, and a fluid chamber for holding oil (fluid) is formed inside the torque converter 1 by both of them. A nut 7 is fixed to the converter cover 6 by welding, and this nut 7 is connected to an engine crankshaft (input shaft) 20 via a drive plate (not shown).

  The stator 4 is supported by a fixed stator shaft (not shown) via a one-way clutch 8. The hub 9 of the turbine runner 3 is coupled with an input shaft (output shaft) 25 by a spline shaft structure or the like so as to rotate integrally.

  The lock-up piston 5 is a member that functions as a friction clutch, and is disposed between the turbine runner 3 and the converter cover 6, and an inner diameter portion thereof is supported by the shaft portion of the hub 9 so as to be movable in the axial direction. . The space between the two is sealed by a seal member 10. Further, the lock-up piston 5 and the hub 9 are designed so as to be able to absorb the fluctuation of the transmission torque through the torsion damper 11.

  A clutch facing 30 (hereinafter simply referred to as the facing 30) serving as a friction material is attached to the outer peripheral portion of the lockup piston 5 serving as a friction clutch on the side facing the inner surface of the converter cover 6. When the lock-up piston 5 moves in a predetermined direction and the facing 30 presses the inner surface of the converter cover 6, a lock-up state is formed. More specifically, by adjusting the pressing force here, a direct connection state (locked state or fastening state) from a released state (a state where the lock-up piston 5 is separated from the converter cover 6) via a slip state is established. (Also called).

  In the structure illustrated in FIG. 1, the interior of the torque converter 1 is partitioned by the lock-up piston 5 into a front chamber 13 on the converter cover 6 side and a rear chamber 14 on the blade element side. Moreover, the code | symbol 15 in FIG. 1 has shown the clearance gap in the state in which the converter cover 6 and the facing 30 are spaced apart.

  And the torque converter 1 with a lockup mechanism of a present Example is a structure which ensures the fastening capacity | capacitance (lockup capacity | capacitance) for fully exhibiting a lockup function in the facing part used as a friction material, and an improvement of cooling performance It is configured to be compatible with the structure for achieving the above. This point will be further described with reference to the drawings. FIG. 2 is a front view (an AX direction view of the facing 30 in FIG. 1) showing an example of the arrangement of two preferable facings 30.

  The facing 30A illustrated in FIG. 2A has a ring shape (ring shape) with respect to the rotation center CP of the lockup piston 5 and the converter cover 6 facing the lockup piston 5. A plurality of grooves SL that allow oil (not shown) to enter and exit between the central side CS and the outer US when the inner wall is pressed with a predetermined pressure or more and fastened is formed along the circumferential direction CD. is there. However, as shown in FIG. 2A, the groove SL is set so that its width changes stepwise in the radial direction RD and becomes wider toward the outside. That is, a narrow groove portion N-SL is set on the center side CS, and a wide groove portion B-SL is set on the outside thereof.

  In the configuration illustrated in FIG. 2A, the facing 30A is formed of a first annular friction material 31 on the center side and a second annular friction material 32 disposed on the outside thereof. The first annular friction material 31 is formed with a first groove N-SL having a constant width in the circumferential direction CD, and the second annular friction material 32 also has a constant width in the circumferential direction CD. Thus, a second groove B-SL wider than the first groove N-SL is formed. Such a structure can be easily manufactured because the groove and arrangement are simple.

In the facing 30A illustrated in FIG. 2A, a groove SL that expands outward in the radial direction RD is formed in a step shape. Part of the oil that lubricates the torque converter 1 passes through the pump impeller 2, the turbine runner 3, and the stator 4 and is supplied to the center CS. This oil passes through the outer wide groove portion B-SL, passes through the inner narrow groove portion N-SL, and reaches the center side CS (anterior chamber 13).
At this time, in the outer wide groove portion B-SL, the wide groove sufficiently comes into contact with the oil to be cooled. On the other hand, since the passage of oil is restricted in the groove portion N-SL whose inner width is narrowed, the amount of oil flowing into the front chamber 13 is restricted, for example, when the lockup mechanism maintains the slip state, and the front chamber 13 Can be controlled well.
In general, since the converter cover 6 is made of a metal having high thermal conductivity, the oil flows so as to contact and replace the peripheral portion, so that the heat is efficiently dissipated and cooled. Accordingly, sufficient cooling can be expected not only on the outer peripheral side of the facing 30A but also on the inner peripheral side where the groove width is narrow. As described above, according to the arrangement of the facing illustrated in FIG. 2A, the cooling of the oil and the surroundings can be promoted. As described above, according to the arrangement of the facing illustrated in FIG. 2A, the cooling of the oil and the surroundings can be promoted.

In addition, since the wide groove portion B-SL is formed on the outer peripheral side, oil entering between the facing 30A and the inner wall of the converter cover 6 is reduced at the time of complete lock-up fastening. Torque is improved.
Further, since the narrowed groove portion N-SL is also formed on the inner side, not a little oil enters between the facing 30A and the inner wall of the converter cover 6 to reduce drag torque and heat generation during slipping.

  As described above, the facing 30A illustrated in FIG. 2A sufficiently widens the width of the outer groove B-SL to ensure a cooling action, and narrows the width of the inner groove N-SL. Thus, the minimum friction coefficient can be maintained and the fastening capacity (torque capacity) can be secured. Therefore, according to this facing 30A, it is possible to realize a lock-up mechanism capable of efficient cooling while ensuring a necessary fastening capacity.

  Further, FIG. 2B is a view showing the facing 30B of another arrangement. Note that in FIG. 2B, portions corresponding to those in FIG. 2A are denoted by the same reference numerals, and redundant description is omitted. In the facing 30B, the first annular friction material 31 on the center side and the second annular friction material 32 on the outer side thereof are spaced apart from each other in the radial direction RD. Thus, by arranging the first annular friction material 31 and the second annular friction material 32 apart from each other, the oil passage increases and the contact area contributing to heat dissipation increases, so that the cooling effect is further improved. Can do.

  According to the torque converter with a lock-up mechanism described above, efficient cooling can be realized while securing a necessary fastening capacity, so that the lock-up state can be always stably realized. Such a torque converter can contribute to an improvement in vehicle fuel efficiency.

In the above-described embodiment, the lock-up piston 5 serves as a friction clutch, which functions as a friction clutch by being pressed inside the converter cover 6, and a clutch facing that serves as a friction material is adhered to the lock-up piston 5 side. Explained the case. However, the facing may be attached to the converter cover 6 side.
Further, a facing may be arranged as an independent member in the gap 15, and when the lock-up piston 5 approaches the converter cover 6, friction may be generated by clamping the clutch facing. In this case, friction surfaces may be set on both surfaces of the independent facing, and the above-described groove portion may be provided on each surface.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed. In the embodiment described above, for the sake of simplicity of explanation, the case where the groove portions N-SL and B-SL having different diameters are set as one set has been illustrated as a single-stage structure, but needless to say, it may be formed in a plurality of stages.

  As described above, according to the present invention, it is possible to provide a torque converter including a lock-up mechanism capable of efficient cooling while ensuring a necessary fastening capacity.

  The friction material includes a first annular friction material on the center side and a second annular friction material disposed on the outer side, and the first annular friction material has a first groove portion having a constant width in the circumferential direction. It is good also as a torque converter with a lockup mechanism in which the 2nd annular friction material formed in the above-mentioned 2nd annular friction material is the constant width in the peripheral direction, and the 2nd groove part wider than the 1st groove part is formed.

  The first annular friction material and the second annular friction material may be spaced apart from each other in the radial direction. In this case, the number of fluid passages is increased, so that the cooling effect can be improved.

It is sectional drawing which showed the main structures of the torque converter with a lockup mechanism which concerns on the Example of this invention. It is the figure which illustrated the preferable facing arrangement | positioning of the friction clutch of a lockup mechanism.

Explanation of symbols

1 Torque converter 2 Pump impeller 3 Turbine runner 5 Lock-up piston (friction clutch)
6 Converter cover 30 Facing (friction material)
N-SL Narrow groove B-SL Wide groove

Claims (3)

A torque converter including a lockup mechanism capable of forming a direct connection state by a friction clutch that connects an input shaft from an engine and an output shaft connected to a wheel,
The friction clutch has a friction material on a surface that is in contact with and separated from an opposing member;
The friction material has a ring shape with respect to the rotation center of the friction clutch, and has a plurality of grooves along the circumferential direction that allow fluid to enter and exit between the center side and the outside. ,
Further, the torque converter with a lock-up mechanism is characterized in that the width of the groove portion changes stepwise in the radial direction and is set wider as it becomes the outer side. The friction material includes a first annular friction material on the center side and a second annular friction material disposed on the outside thereof,
A first groove having a constant width in the circumferential direction is formed in the first annular friction material, and a second groove having a constant width in the circumferential direction and wider than the first groove is formed in the second annular friction material. The torque converter with a lock-up mechanism according to claim 1, wherein the groove portion is formed.   The torque converter with a lockup mechanism according to claim 2, wherein the first annular friction material and the second annular friction material are spaced apart from each other in the radial direction.

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