JP2015124793A - Torque converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque converter superior in transmission efficiency without making a friction material of a lock-up clutch piston unevenly brought into contact with a front cover in locking-up, while suppressing costs.SOLUTION: A torque converter has a front cover 2 and a lock-up clutch piston 16 disposed inside of the front cover, and a friction material 21 is disposed on an outer peripheral portion of a wall portion 19 in the lock-up clutch piston 16. The wall portion 19 of the lock-up clutch piston 16 is provided with a weakened portion 25 bent and deformed in a locking-up state. As the wall portion 19 is bent even when an inner peripheral cylindrical portion 18 of the lock-up clutch piston 16 is largely moved to a side of the front cover 2 with respect to the outer peripheral cylindrical portion 20, the friction material 21 can be prevented from falling down in accompany with the movement of the inner peripheral cylindrical portion 18, and the friction material 21 is kept in a state of being closely in contact with the front cover 2. As processing of the friction material 21 is unnecessary, and processing of the weakened portion 25 is easy, costs are not increased.

Description

  The present invention relates to a torque converter (fluid torque converter) for shifting the rotation of an internal combustion engine or the like.

  In the torque converter, housing is constituted by a front cover and a pump impeller, and rotation of the front cover is transmitted to the turbine liner via oil. As the oil flow changes, the reduction ratio is adjusted steplessly, and torque is transmitted from the front cover (main shaft) to the output shaft via the turbine liner. In the case of a conventional torque converter, transmission efficiency deteriorates when the vehicle speed reaches a certain level.

  Therefore, when the vehicle speed reaches a certain speed (for example, about 20 km / h), the front cover and the output shaft are directly connected via the lockup clutch piston. This lock-up clutch piston has a substantially ring shape and is slidably mounted on a turbine hub to which a turbine liner is fixed. By changing the direction of hydraulic pressure, the lock-up clutch piston can approach the front cover. To leave. A ring plate-like friction material facing the front cover is disposed at a position near the outer periphery of the lock-up clutch piston. In the lock-up state, the friction material adheres to the front cover so that the front cover The rotation is transmitted to the lockup clutch piston.

  The reason why the friction material is arranged near the outer periphery of the lock-up clutch piston is to increase the moment as much as possible to increase the transmission efficiency and to increase the contact area as much as possible to eliminate slippage. The pressure acting on the inner periphery side of the friction material becomes larger than the pressure acting on the location of the friction material, so that the lock-up clutch piston tilts in a locked-up state when viewed from the direction perpendicular to the rotation axis, In some cases, the friction material hits only the portion on the inner peripheral side against the front cover. If the friction material hits the front cover, slippage may occur between the friction material and the front cover, which may reduce power transmission efficiency or cause seizure of the friction material.

  In this regard, in Patent Document 1, the surface of the friction material is formed in a convex convex surface facing the front cover in a state viewed from the direction orthogonal to the rotation axis, while the portion of the front cover that the friction material hits is Further, it is disclosed that the friction material is brought into close contact with the front cover in the same state even when the lockup clutch piston is inclined by forming a concave curved surface having a radius of curvature larger than the radius of curvature of the arc of the friction material.

JP 2012-87810 A

  The friction material is manufactured with a special material, and it takes a considerable amount of time to manufacture the cross-sectional shape of the convex curved surface as in Patent Document 1. Further, in Patent Document 1, since the front cover must also be processed with a concave surface, it takes time to process the front cover. For this reason, in patent document 1, it cannot be avoided that cost increases considerably.

  Further, in Patent Document 1, since the radius of curvature of the convex curved surface of the friction material is smaller than the radius of curvature of the concave curved surface of the front cover, the friction material and the front cover are in contact with each other only in a state close to line contact. As a result, when the torque transmitted from the front cover is large, for example, when traveling uphill, slippage occurs between the friction material and the front cover, and the same as in the one-touch state. Problems may occur.

  The present invention has been made to improve the current situation.

  In the torque converter according to the present invention, a substantially ring-shaped lock-up clutch piston that moves toward and away from the front cover is disposed between the front cover and the turbine liner. A friction material that can be brought into close contact with the inner side surface of the front cover is disposed at a location, and by changing the direction of the hydraulic pressure applied to the lock-up clutch piston, the lock-up clutch piston is changed to the friction material to the front cover. The basic configuration is that the lock-up position in close contact with the friction material and the friction material can be switched to a free position away from the front cover.

  In the basic configuration, when the lock-up clutch piston is pushed to the lock-up position by hydraulic pressure in a portion of the lock-up clutch piston that is on the inner peripheral side with respect to the friction material, it is orthogonal to the rotational axis. A weakening portion is provided to hold the friction material in close contact with the front cover by bending and deforming against elasticity when viewed from the direction.

  The weakened portion can employ various structures such as thinning. Moreover, the location where the weakened portion is provided need not be one in the radial direction, and may be formed in a plurality of locations in the radial direction. Moreover, the deformation | transformation aspect of a weakened part is not restricted to bend in a narrow range like a hinge, It may have a certain amount of width | variety and may curve.

  In the conventional structure, the friction material hits the front cover in the locked-up state, as described above, the pressure acting on the friction material portion is the pressure acting on the inner peripheral side of the friction material. This is because the inner peripheral portion of the lockup clutch piston is strongly pushed toward the front cover due to the smaller size, but this is because the rigidity of the lockup clutch piston is high. That is, the lock-up clutch piston is inclined in a state like a seesaw because of its high rigidity.

  On the other hand, in the present invention, since the weakened portion is provided on the inner peripheral side of the friction material among the lockup clutch piston, the lockup clutch piston bends around the weakened portion, thereby While permitting the inner peripheral portion to greatly approach the front cover, the friction material can be kept in close contact with the front cover throughout.

  In other words, even in the present invention, the lock-up clutch piston has a tendency that the inner peripheral portion is closer to the front cover than the outer peripheral portion when locked, but the weakening portion blocks the movement of the inner peripheral portion from affecting the friction material. Therefore, the friction material can be held in close contact with the front cover.

  In the present invention, the friction material and the front cover do not require any special processing, and the weakened portion of the lock-up clutch piston can be simply processed such as thinning, so that the cost can be remarkably suppressed. Therefore, in the present invention, a torque converter having excellent power transmission efficiency can be realized at low cost. Further, the weakened portion extends long in the circumferential direction and is strong against circumferential torsion, so that it is not twisted by torque transmission.

  In addition, since the impact is absorbed (buffered) when the weakened portion is deformed at the time of shifting to the lock-up, it can be said that it can contribute to a smooth transition to the lock-up state.

It is a vertical side view in the free state of the torque converter which concerns on embodiment. (A) is a partially broken longitudinal side view at the time of transition to the lock-up state, (B) is a schematic cross-sectional view in the lock-up state, and (C) is a view of a comparative example. It is a figure which shows other embodiment.

(1) Structure of First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. First, the first embodiment shown in FIGS. The basic elements of the torque converter are the same as those of the conventional one, and the front cover 3 fixed to the main drive shaft (crankshaft) 2 and the output shaft (driven shaft) 4 are fitted from the outside as the elements of the housing 1 constituting the exterior. A pump impeller 5. While the outer peripheral portion of the front cover 3 is a cylindrical portion 3 a, the pump impeller 5 has a bowl shape whose outer periphery is formed with the cylindrical portion 5 a, and both the cylindrical portions 3 a and 5 a are integrated by a welded portion 6. ing.

  A plurality of blades (blades) 7 are provided on the inner surface of the pump impeller 4, and a turbine liner 9 that forms an egg-shaped ring-shaped fluid chamber 8 with the pump impeller 4 is formed in the housing 1. A plurality of blades (blades) 10 are provided on the surface of the turbine liner 9 facing the pump impeller 4. A stator 11 is disposed between the pump impeller 4 and the turbine liner 9 at a portion on the inner peripheral side of the fluid chamber 8.

  The stator 11 is fitted to a sleeve 13 via a one-way clutch 12, and the sleeve 13 is splined to the output shaft 4. Further, a turbine hub 14 having a disk-like portion 14 a is fitted by spline fitting to a portion of the output shaft 4 closer to the front cover 2 than the sleeve 13, and the disk-like portion 14 a of the turbine hub 14 is fitted. A turbine liner 9 is fixed to one side surface with a rivet 15 or the like.

  Further, an outer cylinder part 14b is provided on the outer periphery of the disk-like part 14a in the turbine hub 14, and a ring-shaped lockup clutch piston 16 is fitted to the outer cylinder part 14b so as to be slidable in the axial direction. . A stopper 14c protruding in the outer peripheral direction is provided at the end of the outer cylinder portion 14b on the turbine liner 9 side. Further, an O-ring 17 is attached to the outer cylinder portion 14b.

  The lockup clutch piston 16 is made of a metal plate, and has an inner peripheral cylindrical portion 18 that fits in the outer cylindrical portion 14 b of the turbine hub 14, a wall portion 19 that is integrally continuous with the inner peripheral cylindrical portion 18, and an outer periphery of the wall portion 19. And the outer peripheral cylindrical portion 20 which is integrally continuous with each other, and the cross-sectional shape is substantially U-shaped. The wall portion 19 includes a first stepped portion 19b that is displaced from the inner peripheral portion 19a that is continuous in a posture orthogonal to the inner peripheral cylindrical portion 18 toward the front cover 2, and a front cover that further extends from the outer peripheral edge of the first dropped portion 19b. 2 and a second stepped-down portion 19c that is shifted to the second side, and a ring-plate-shaped friction material 21 having an equal thickness is fixed to the outer surface of the second stepped-down portion 19c.

  About a half of the first stepped portion 19b on the outer peripheral side slightly approaches the turbine liner 9 side, and an outer damper plate 22 is fixed to this portion with a fastener 23 such as a rivet. On the other hand, an inner damper plate 24 corresponding to the outer damper plate 22 is fixed to the outer surface of the turbine liner 9, and the outer damper plate 22 and the inner damper plate 24 make a spring 25 arranged in a jumping manner in the circumferential direction. And the other end. Needless to say, the spring 24 (damper device) is for absorbing an impact at the time of the lock-up transition.

  Then, the thinned weakened portion 26 is spread over the entire circumference in a portion of the first stepped portion 19b of the wall portion 19 of the lockup clutch piston 16 that is slightly closer to the inner circumference than the outer damper plate 22. Forming. The weakening part 26 is formed by taking the meat of the inner surface of the first stepped-down part 19b on the turbine liner 9 side. Specifically, it is formed by crushing by cutting or a press machine. The weakened portion 26 has an equal pressure, and thus a rectangular groove is formed. However, the groove may be formed in a V shape or a U shape.

(2) Summary of First Embodiment A space between the front cover 2 and the turbine liner 9 is divided into an inner space 27 and an outer space 28 by the lock-up clutch piston 16, and the hydraulic pressure in these spaces 27 and 28 is divided. By changing the pressure, the lockup clutch piston 16 can be urged to a free position away from the front cover 2, or the lockup clutch piston 15 can be urged to a lockup position in close contact with the front cover 2. it can.

  When the vehicle is traveling at a low speed, the hydraulic fluid flows from the outer space 28 to the inner space 27 and the lockup clutch piston 16 releases the friction material 21 from the front cover 2 (lockup release position). In this free position, the rotation of the pump impeller 5 is transmitted to the turbine liner 9 via the hydraulic oil, and the rotation of the turbine liner 9 is transmitted to the output shaft 4 via the turbine hub 14.

  On the other hand, for example, when the vehicle speed increases to a certain degree or the throttle valve is fully opened and the torque conversion is not necessary, the hydraulic oil flows into the inner space 27 and the lockup clutch piston 16 moves to the lockup position. At the position, the friction material 21 comes into close contact with the front cover 2, whereby the front cover 2, the lockup clutch piston 15 and the turpin hub 14 rotate integrally, and the rotation of the front cover 2 is directly transmitted to the output shaft 4 ( A black arrow in FIG. 2A indicates a power transmission path.

  The lock-up clutch piston 16 has a small hole through which hydraulic oil can be removed and a case where the small hole is not formed. When the small hole is formed, the lock-up clutch piston 16 has an inner space 27 and an outer space 28. Is pushed toward the front cover 2 by the pressure difference.

  Since the friction material 21 is provided only in a small range on the outer peripheral side of the lock-up clutch piston 15, the area of the friction material 21 is smaller than the area inside the friction material 21, As schematically shown in FIG. 2C, when the pressure of the hydraulic pressure acting on the friction material 21 is P1, and the pressure acting on the inner peripheral side of the friction material 21 is P2, P1 is smaller than P2. It has become.

  As a result, unless special measures are taken, as shown schematically in FIG. 2C, the inner peripheral portion of the lock-up clutch piston 15 moves to the front cover 2 side larger than the outer periphery, and the lock-up clutch The piston 15 is inclined, and therefore, the one-side contact phenomenon in which only the inner peripheral portion of the friction material 21 contacts the front cover 2 is likely to occur.

  On the other hand, in this embodiment, since the weakened portion 26 exists in the lockup clutch piston 15, as schematically shown in FIG. 2B, the inner peripheral cylindrical portion 18 of the lockup clutch piston 15 is the outer peripheral cylinder. Even if the front cover 2 is closer to the side than the portion 20, the lock-up clutch piston 15 bends and deforms against elasticity, and the location of the friction material 21 falls due to the movement of the inner peripheral cylindrical portion 18. As a result, the friction material 21 can be brought into close contact with the front cover 2 over the entirety thereof.

  Therefore, the slip between the friction material 21 and the front cover 2 can be prevented to maintain high power transmission efficiency, and the durability of the torque converter can be improved. Further, the front cover 2 and the friction material 21 do not require any special processing, and the weakened portion 25 can be easily processed by cutting or pressurization, so that the cost increase can be remarkably suppressed.

(3). Other Embodiments, Others FIG. 3 shows another embodiment. Of these, in the embodiment shown in (A), the thinned weakened portion 25 is formed by removing the meat from the inner surface and the outer surface of the wall portion 19 of the lockup clutch piston 16. In order to maintain the adhesion of the friction material 21 to the front cover, as shown in FIG. 3A, the area of the area outside the inner periphery of the friction material 21 is S1, and the inner periphery of the friction material 21 is weakened. When the area of the area between the portions 25 is S2, it is preferable that S1> S2.

  In the embodiment shown in (B), two rows of thin weakened portions 25 are provided concentrically on the first stepped portion 19b of the wall portion 19. In the embodiment shown in (C), a weakened portion 25 bulging outward (front cover side) with a small radius of curvature is formed in the first stepped portion 19 of the wall portion 19. The bulging direction of the weakening portion 25 may be reversed. (A) As shown by the alternate long and short dash line in (B), it is also possible to provide a thinned weakened portion 25 in the bent portion between the inner peripheral portion 19a and the first stepped portion 19b in the wall portion 19. It is.

  Although description in the drawing is omitted, it is possible to concentrate stress on the weakened portion by providing reinforcing ribs on the inner peripheral side and the outer peripheral side across the weakened portion. Alternatively, it is also possible to form a weakened portion by bending a part of the wall portion into a cross-sectional waveform (in a concavo-convex shape) in a state viewed from a direction orthogonal to the rotation axis as in each figure (in this case) It is also possible to see that a plurality of weakened parts are continuous.) Although the lockup clutch piston of the embodiment has two stepped portions, the lockup clutch piston may be a simple U-shape or the like.

  As described above, the lock-up clutch piston has a small hole through which hydraulic oil is released. However, it is preferable to provide a weakened portion at a position where the small hole is provided because the weakened portion is more easily bent.

  The present invention can be actually embodied in a torque converter. Therefore, it can be used industrially.

1 Housing 1
2 Crankshaft (input shaft)
DESCRIPTION OF SYMBOLS 3 Front cover 4 Output shaft 5 Pump impeller 9 Turbine liner 14 Turbine hub 16 Lockup clutch piston 18 Inner peripheral cylinder part 19 Wall part 19a Inner peripheral part 19b 1st step fall part 19c 2nd step fall part 21 Friction material 25 Weakening part 25

Claims (1)

Between the front cover and the turbine liner, a substantially ring-shaped lock-up clutch piston that moves toward and away from the front cover is disposed, and the front cover is disposed at a position near the outer periphery of the lock-up clutch piston. A friction material that can be in close contact with the inner surface is disposed, and by changing the direction of the hydraulic pressure applied to the lock-up clutch piston, the lock-up clutch piston has a lock-up position where the friction material is in close contact with the front cover. The friction material is configured to be switched to a free position away from the front cover,
When the lock-up clutch piston is pushed to the lock-up position by hydraulic pressure at a position on the inner peripheral side of the friction material of the lock-up clutch piston, it resists elasticity when viewed from the direction perpendicular to the rotation axis. A weakening portion is provided to hold the friction material in close contact with the front cover over the entire surface by bending and deforming.
Torque converter.

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