JP2014047811A - Torque converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness in clutch connection of a lock-up clutch by a simple configuration.SOLUTION: A torque converter includes: a front cover 3; an impeller 4 whose outer peripheral part is fixed on the front cover 3 by welding; a turbine 5; a stator 6; and a lock-up clutch 8 for directly transmitting torque from the front cover 3 to the turbine 5. The lock-up clutch 8 has a piston 30 in which a frictional member 34 is fixed and moved in an axial direction by hydraulic pressure and the frictional member 34 is pressed to the front cover 3. The piston 30 is arranged so that the frictional member 34 is brought into contact with the front cover 3 in a state that hydraulic pressure for actuating the piston is not supplied and the frictional member 34 is separated from the front cover 3 in a state that hydraulic oil is supplied between the front cover 3 and the piston 30.

Description

  The present invention relates to a torque converter, and more particularly to a torque converter provided with a lock-up clutch.

  The torque converter is a device that transmits torque from the engine to the transmission side via an internal working fluid, and mainly includes a front cover, an impeller, a turbine, and a stator.

  The torque converter is provided with a lock-up clutch in order to improve torque transmission efficiency. The lock-up clutch is disposed in a space between the front cover and the turbine, and in a region where the function of the torque converter is not required, the front cover and the turbine are mechanically connected to generate torque from the front cover to the turbine. Communicate directly. Specifically, the lockup clutch has a piston that is movable in the axial direction by hydraulic pressure. A friction member is fixed to the outer peripheral portion of the piston, and the friction member is pressed against the friction surface of the front cover to be connected to the front cover.

  As described above, when the piston of the lockup clutch moves in the axial direction, the lockup clutch is turned on (clutch coupled state). Therefore, in order to improve the response of the lockup clutch, it is necessary to quickly move the piston to the front cover side.

  Therefore, in the torque converter disclosed in Patent Document 1, a plate spring is fixed to the piston, and a friction member is fixed to the plate spring. The responsiveness of the lockup clutch is improved by pressing the friction member against the front cover with a leaf spring in a state where the hydraulic pressure is not applied to the piston.

  Further, in the torque converter disclosed in Patent Document 2, an annular sliding member is disposed between the inner peripheral portion of the piston and the outer peripheral surface of the turbine hub, and the responsiveness of the lockup clutch is suppressed by suppressing the frictional resistance of the sliding portion. Has improved.

Japanese Patent Laid-Open No. 11-63152 JP 2006-29357 JP

  In the torque converters of Patent Documents 1 and 2, by providing a leaf spring on the piston or by providing a sliding member between the piston and the turbine hub, the friction member of the piston is moved to the front when the lockup clutch is connected. It moves quickly to the cover side.

  However, in the configuration of these patent documents, a leaf spring and a sliding member are required, which causes an increase in cost.

  An object of the present invention is to improve the responsiveness at the time of clutch engagement of a lockup clutch with a simple configuration.

  A torque converter according to a first aspect of the present invention includes a front cover to which torque from the engine side is input, an impeller having an outer peripheral portion fixed to the front cover by welding, a turbine disposed to face the impeller, A stator disposed between the inner periphery of the impeller and the turbine, and a lockup clutch for directly transmitting torque from the front cover to the turbine. The lock-up clutch has a piston whose friction member is fixed to the outer peripheral portion, moves in the axial direction by hydraulic pressure, and is pressed against the front cover. The piston contacts the front cover when the hydraulic pressure for operating the piston is not supplied, and the friction member separates from the front cover when the hydraulic oil is supplied between the front cover and the piston. Are arranged as follows.

  Here, in the torque converter, when the outer periphery of the front cover and the impeller is welded, the torque converter swells in the axial direction. Further, when a fluid is supplied to the inside of the torque converter, the front cover and the impeller swell in the axial direction so as to be separated by internal pressure and by hydraulic pressure by centrifugal force. That is, when the torque converter is assembled, the piston friction member and the front cover are in contact with each other before the front cover and the impeller are welded and before the fluid is supplied into the torque converter. However, by arranging the pistons at appropriate positions, a gap can be created between them in use.

  Therefore, in the present invention, the piston friction member and the front cover are arranged so as to come into contact with each other before use and to be separated from each other in actual use.

  For this reason, the clearance between the friction member of the piston and the front cover during actual use can be minimized, and the responsiveness when the lockup clutch is engaged can be improved. Further, a special member used in the conventional torque converter is not necessary here, and an increase in cost can be avoided.

  In the torque converter according to the second aspect of the present invention, in the torque converter according to the first aspect, the friction member is in pressure contact with the front cover in a state where hydraulic pressure is not applied to the piston.

  Here, before use, the friction member of the piston is pressed against the front cover. That is, the gap between the two is set to “minus” instead of “0”. For this reason, the clearance gap between both at the time of actual use can be made smaller, and responsiveness can be improved further.

  In the torque converter according to the third aspect of the present invention, in the torque converter according to the first or second aspect, the friction member has a tapered portion that is inclined so as to be separated from the front cover toward the outer peripheral side. ing.

  In use, when the torque converter swells due to internal pressure, the inner circumference side is more likely to swell than the outer circumference side. That is, even when the torque converter swells in the axial direction during use, the amount of swell is smaller on the outer peripheral side than on the inner peripheral side.

  Therefore, in the torque converter of the third side surface, a tapered portion is provided on the outer peripheral side of the friction member. As a result, even when the bulge of the torque converter during use is small, a gap can be reliably ensured between the friction member and the front cover.

  The torque converter according to a fourth aspect of the present invention further includes an adjustment member for adjusting the distance between the friction member and the front cover in any one of the first to third torque converters.

  Here, since the gap between the friction member and the front cover can be adjusted by the adjustment member, it is not necessary to strictly manage the dimensional accuracy and assembly accuracy of each member. Therefore, manufacture becomes easy.

  A torque converter according to a fifth aspect of the present invention is the torque converter according to the fourth aspect, wherein the turbine is fixed to a turbine shell, a plurality of turbine blades fixed inside the turbine shell, and an inner peripheral portion of the turbine shell. And a turbine hub for outputting torque. The piston is formed in an annular shape, and has a cylindrical portion extending toward the turbine hub on the inner peripheral portion, and the inner peripheral surface of the cylindrical portion is slidably supported on the outer peripheral surface of the turbine hub. . And the adjustment member is arrange | positioned between the axial direction front-end | tip of a cylindrical part, and the turbine hub.

  In the present invention as described above, the response of the lockup clutch when the clutch is engaged can be improved with a simple configuration.

The longitudinal cross-section block diagram of the torque converter by one Embodiment of this invention. The elements on larger scale of a friction member.

[overall structure]
FIG. 1 shows a longitudinal section of a torque converter 1 according to an embodiment of the present invention. An engine (not shown) is arranged on the left side of FIG. 1, and a transmission (not shown) is arranged on the right side of the figure. Further, OO shown in FIG. 1 is a rotation axis of the torque converter 1.

  The torque converter 1 is a device for transmitting torque from a crankshaft (not shown) on the engine side to a drive shaft 2 of a transmission, and includes a front cover 3 to which torque from the engine is input and three types of impellers. A torque converter main body 7 including an impeller 4, a turbine 5, and a stator 6, and a lockup clutch 8 are included.

  The front cover 3 is a disk-shaped member, and mainly includes a disk part 3a and an outer peripheral cylindrical part 3b that is formed on the outer peripheral part of the disk part 3a and protrudes toward the axial transmission side. ing. The outer peripheral cylindrical portion 3b is fixed to the outer peripheral portion of the impeller 4 by welding.

  The impeller 4 has an impeller shell 10 and a plurality of impeller blades 11 fixed to the inside thereof. As described above, the outer peripheral portion of the impeller shell 10 is welded to the distal end portion of the outer peripheral cylindrical portion 3b of the front cover 3.

  The turbine 5 is disposed to face the impeller 4 in the fluid chamber. The turbine 5 includes a turbine shell 13, a plurality of turbine blades 14 fixed to the turbine shell 13, and a turbine hub 15 fixed to the inner peripheral portion of the turbine shell 13.

  The turbine hub 15 has a cylindrical portion 15a extending in the axial direction and a disk-shaped flange portion 15b extending radially outward from the cylindrical portion 15a. A spline hole 15c is formed in the inner peripheral portion of the cylindrical portion 15a, and the drive shaft 2 of the transmission can be engaged with the spline. An inner peripheral portion of the turbine shell 13 is fixed to the flange portion 15 b by a rivet 16.

  The stator 6 is a mechanism for adjusting the flow of hydraulic oil that is disposed between the impeller 4 and the inner peripheral portion of the turbine 5 and returns from the turbine 5 to the impeller 4. The stator 6 is mainly composed of an annular stator carrier 18 and a plurality of stator blades 19 provided on the outer peripheral surface thereof. The stator carrier 18 is supported by a fixed shaft (not shown) via a one-way clutch 20 so as to be rotatable in one direction.

  Further, a thrust washer 22 is provided between the front cover 3 and the tip of the cylindrical portion 15a of the turbine hub 15 in the axial direction. Further, a first thrust bearing 23 is provided between the flange portion 15 b of the turbine hub 15 and the one-way clutch 20, and a second thrust bearing 24 is provided between the stator carrier 18 and the impeller shell 10.

[Lock-up clutch]
The lockup clutch 8 is a device for mechanically connecting the front cover 3 and the turbine 5. The lock-up clutch 8 mainly elastically connects the piston 30 and the retaining plate 31 to which torque is input from the front cover 3, the driven plate 32, and the retaining plate 31 and the driven plate 32 in the rotational direction. It comprises a plurality of torsion springs 33.

  The piston 30 is a disk-shaped plate member, and a friction member 34 is fixed to the outer peripheral portion. The piston 30 moves in the axial direction by controlling the oil pressure on the front cover 3 side and the turbine 5 side, and presses the friction member 34 against the side surface of the front cover 3 (the lock-up clutch is on (connected)). Alternatively, it can be separated from the side surface of the front cover 3 (the lock-up clutch is off (disengaged)).

  As shown in an enlarged view in FIG. 2, the friction member 34 has a tapered portion 34 a that is inclined so as to move away from the front cover 3 toward the outer peripheral side at the outer peripheral portion. In FIG. 2, the state in which the front cover 3 is swollen by internal pressure or the like is exaggerated.

  As apparent from FIG. 2, when the friction member 34 is not formed with the tapered portion 34 a (the shape indicated by the two-dot chain line in FIG. 2), when the front cover 3 is deformed, the friction member 34 contacts the outer peripheral end. there is a possibility. However, by providing the tapered portion 34a, it is possible to suppress contact with the friction member 34 even if the front cover 3 is deformed. Therefore, it is possible to avoid the occurrence of drag.

  An outer peripheral cylindrical portion 30a extending toward the axial transmission side is provided on the outer peripheral portion of the piston 30, and an inner peripheral cylindrical portion 30b extending in the same direction is provided on the inner peripheral portion. The inner peripheral cylindrical portion 30b is supported on the outer peripheral surface of the cylindrical portion 15a of the turbine hub 15 so as to be slidable in the axial direction. A shim 35 for adjusting the initial position of the piston 30 is provided between the end surface of the inner peripheral cylindrical portion 30 b and the flange portion 15 b of the turbine hub 15.

  A seal member 36 is provided between the inner peripheral cylindrical portion 30 b of the piston 30 and the cylindrical portion 15 a of the turbine 15.

  The retaining plate 31 is disposed on the inner peripheral side of the outer peripheral cylindrical portion 30 a of the piston 30 on the turbine 5 side of the piston 30. The retaining plate 31 includes a holding portion 31 a that holds a plurality of torsion springs 33, and an engaging portion 31 b that engages with the rotation direction end of the torsion spring 33. Further, the inner peripheral portion 31 c of the retaining plate 31 is fixed to the piston 30 by a rivet 35.

  The driven plate 32 is a disk-shaped plate member, and is disposed between the piston 30 and the turbine 5. The driven plate 32 has an inner peripheral portion 32 a fixed to the turbine hub 15 flange portion 15 together with the turbine shell 14 by rivets 16. A plurality of engaging portions 33 b that engage with both ends of the torsion spring 33 are formed on the outer peripheral portion of the driven plate 32.

  The torsion spring 33 is composed of a coil spring that absorbs and attenuates minute torsional vibration caused by fluctuations in engine rotation and vibration caused by shock when the lockup clutch 8 is connected. The torsion spring 33 elastically deforms between the spring holding portion 31a of the retaining plate 31 and the engaging portion 33b of the driven plate 33 to elastically connect the piston 30 and the driven plate 32 in the rotational direction. To do.

[Piston arrangement]
Here, the gap between the friction member 34 to which the piston 30 is fixed and the front cover 3 is preferably small in order to improve the response when the lockup clutch is on. On the other hand, if there is no gap, drag torque is generated when the lockup clutch is off, so a certain amount of gap is required.

  Here, in assembling the torque converter, when the front cover 3 and the impeller shell 10 of the impeller 4 are welded, the front cover 3 and the impeller 4 swell in a direction away from each other in the axial direction. Further, when a fluid is supplied to the inside of the torque converter and the torque converter rotates, the front cover 3 and the impeller 4 similarly swell in a direction away from each other by centrifugal hydraulic pressure.

  Therefore, by design, before the front cover 3 and the impeller 4 are welded, the friction member 34 of the piston 30 contacts the front cover 3 (the gap is “0”), or the friction member 34 is the front cover 3. If the dimensions are set so as to be in pressure contact (the gap is minus), the gap between the friction member 34 and the front cover 3 can be made as small as possible when the torque converter is actually used.

  An example is given below.

(A) During assembly before welding The clearance between the friction member 34 and the front cover 3 is set to 0 to −0.4 mm. This gap adjustment is facilitated by selecting a shim 35 having an appropriate thickness, but it is of course possible to adjust the gap without using the shim 35.

(B) Deformation by welding Based on experience values, 0.02mm for the front cover and 0.3mm for the impeller are expected.

(C) Deformation due to hydraulic pressure supplied to the torque converter + centrifugal hydraulic pressure during idle rotation Based on empirical values, it is expected to be 0.03 mm for the front cover and 0.25 mm for the impeller.

In the above example, the gap between the friction member and the front cover is
Maximum gap = 0.02 + 0.3 + 0.03 + 0.25 = 0.6mm
Minimum clearance = 0.02 + 0.3 + 0.03 + 0.25-0.4 = 0.2mm
It is expected to be.

[Operation]
About operation | movement of a torque converter, it is the same as that of the past. That is, torque from the crankshaft on the engine side is input to the front cover 3. As a result, the impeller 4 rotates and hydraulic oil flows from the impeller 4 to the turbine 5. The turbine 5 rotates by the flow of the hydraulic oil, and the torque of the turbine 5 is output to the drive shaft 2 connected to the turbine hub 15.

  Further, when the speed ratio of the torque converter increases and the drive shaft 2 reaches a constant rotational speed, the hydraulic fluid in the space between the piston 30 and the front cover 3 is drained, and between the piston 30 and the turbine 5. Hydraulic fluid is supplied to the space. As a result, the hydraulic pressure in the space on the turbine 5 side of the piston 30 becomes higher than the hydraulic pressure in the space on the front cover 3 side, and the piston 30 is moved to the front cover 3 side. Then, the friction member 34 fixed to the piston 30 is pressed against the side surface of the front cover 3. Thereby, the torque from the engine is transmitted from the front cover 3 to the piston 30 and the retaining plate 31, and further output to the drive shaft 2 via the torsion spring 33, the driven plate 32 and the turbine hub 15.

  At this time, the gap between the friction member 34 and the front cover 3 is very small due to the arrangement of the piston 30 as described above. For this reason, the responsiveness of the lockup clutch is improved.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

  Specific numerical values for the clearance adjustment are merely examples, and it is needless to say that the numerical values are not limited to these numerical values.

DESCRIPTION OF SYMBOLS 1 Torque converter 3 Front cover 4 Impeller 5 Turbine 6 Stator 8 Lockup clutch 13 Turbine shell 14 Turbine blade 15 Turbine hub 30 Piston 30b Inner peripheral cylindrical part 34 Friction member 34a Taper part 35 Shim

Claims (5)

A front cover to which torque from the engine is input,
An impeller having an outer peripheral portion fixed to the front cover by welding;
A turbine disposed opposite the impeller;
A stator disposed between the inner periphery of the impeller and the turbine;
A lock-up clutch for transmitting torque from the front cover directly to the turbine, the piston having a friction member fixed to the outer periphery, moved in the axial direction by hydraulic pressure, and pressed against the front cover; ,
With
The piston is configured such that the friction member is in contact with the front cover when the hydraulic pressure for operating the piston is not supplied, and the friction member is in a state where hydraulic oil is supplied between the front cover and the piston. Disposed away from the front cover,
Torque converter.   The torque converter according to claim 1, wherein the friction member is pressed against the front cover in a state where hydraulic pressure is not applied to the piston.   3. The torque converter according to claim 1, wherein the friction member has a tapered portion that is inclined so as to be separated from the front cover as it goes toward the outer peripheral side.   The torque converter according to any one of claims 1 to 3, further comprising an adjustment member for adjusting a distance between the friction member and the front cover. The turbine includes a turbine shell, a plurality of turbine blades fixed inside the turbine shell, and a turbine hub that is fixed to an inner peripheral portion of the turbine shell and outputs torque.
The piston is formed in an annular shape and has a cylindrical portion extending toward the turbine hub on an inner peripheral portion, and an inner peripheral surface of the cylindrical portion is slidably supported on an outer peripheral surface of the turbine hub. And
The adjustment member is disposed between the axial tip of the cylindrical portion and the turbine hub.
The torque converter in any one of Claim 1 to 4.

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