JP3455600B2 - Lockup clutch for torque converter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up clutch, and more particularly to a lock-up of a torque converter for transmitting torque via fluid from an impeller connected to an input side front cover to a turbine connected to an output side member. Regarding the clutch.

[0002]

2. Description of the Related Art Some conventional torque converters are equipped with a lockup clutch for directly transmitting an input side member and an output side member to transmit power without passing through the torque converter body. When the vehicle starts, torque is input to the torque converter from the input side member. Here, the vehicle smoothly starts due to the torque increasing action of the torque converter. When the number of rotations of the input shaft of the transmission reaches a constant value, the lockup clutch operates and torque is directly transmitted from the input side member to the transmission input shaft. At this time, since the torque is mechanically transmitted, the vehicle travels in a fuel-efficient state.

In order to suppress the generation of noises such as rattling noises and muffled noises of the truss mission during the general running of the vehicle, the resonance frequency is set to the idle speed (practical speed) of the vehicle.
It needs to be lowered below. In the conventional vehicle, in a general traveling state in which the lockup device is operating, the power transmission system is divided into an input side and an output side with the coil spring of the lockup clutch as a boundary. In this power transmission system, in order to set the resonance frequency to be equal to or lower than the idle speed, it is necessary to sufficiently increase the inertia moment ratio of the output side to the input side. However, when the lockup clutch is disengaged, it is preferable to reduce the inertial mass of the output side mechanism so as not to adversely affect the transmission side clutch and the like.

Therefore, a mechanism has been proposed in which an annular weight is connected to and separated from a lockup clutch by a centrifugal force mechanism. According to this, when the rotational speed of the turbine increases, the annular weight is coupled to the output side member such as the turbine by the centrifugal force. As a result, the inertia moment ratio of the output side mechanism becomes large, and the resonance number in the drive system can be lowered to the low frequency region. When the rotational speed of the turbine decreases, the annular weight is separated from the output side member such as the turbine. As a result, problems such as the clutch of the transmission are unlikely to occur.

[0005]

Since the conventional weights are connected and disconnected by the centrifugal force mechanism, it is difficult to perform accurate control. An object of the present invention is to accurately control connection or disconnection of a weight member to an output side mechanism in a lockup clutch of a torque converter.

[0006]

A lockup clutch for a torque converter according to the present invention is for transmitting torque from a impeller connected to an input side front cover to a turbine connected to an output side member via a fluid. It is provided with a weight member, a piston member, an elastic member, an output side plate, and a hydraulic control device. The weight member is arranged between the front cover and the turbine. The piston member is arranged laterally of the weight member and is movable in the axial direction. The elastic member connects the piston member and the front cover in the circumferential direction. The output side plate is disposed between the weight member and the piston member and is connected to the output side member. The hydraulic control device moves the piston member in the axial direction by hydraulic control in the torque converter.

The elastic member preferably comprises a bent leaf spring. It is preferable to further include a viscous fluid filling chamber that accommodates the bent leaf spring. The bent leaf spring preferably has a hole through which a viscous fluid passes. The bent leaf spring is formed by connecting a plurality of spring elements in series, and the spring elements extend so as to be spaced apart from each other with a ring portion partially having an open ring portion and outward from the open ring portion. It preferably has a pair of lever portions.

[0008]

In the lockup clutch according to the present invention, when the hydraulic control device controls the hydraulic pressure in the torque converter, the piston member moves axially and separates from the output side plate. At this time, the weight member is not connected to either the input side mechanism or the output side mechanism.

When the piston member is moved in the axial direction by the hydraulic control in the torque converter by the hydraulic control device, the output side plate is sandwiched between the weight member and the piston member. As a result, the torque of the front cover is transmitted to the output side plate via the elastic member and further output to the output side member. At this time, the weight member increases the inertia moment ratio of the output side mechanism to the input side mechanism. As a result, the resonance frequency in the power transmission system including the torque converter can be reduced to be equal to or lower than the idle speed of the engine, and abnormal noise such as rattling noise and muffled noise generated on the transmission side can be suppressed.

Particularly, in this lockup clutch, since the lockup clutch can be turned on / off and the weight member can be connected / disconnected by hydraulic control,
Control can be performed accurately. When the second elastic member is composed of a bent leaf spring, the bent leaf spring can have a smaller width dimension than the coil spring, so that the axial direction of the entire lockup clutch can be shortened.

When the viscous fluid filling chamber is further provided, the bending leaf spring expands and contracts in the viscous fluid filling chamber.
By this expansion and contraction, the viscous fluid passes through the gap between the bent leaf spring and the viscous fluid filled chamber, and a predetermined viscous resistance is generated.
In this way, both functions of the conventional elastic coupling mechanism and frictional resistance generating mechanism can be realized by the viscous fluid-filled chamber and the bent leaf spring, and the size of the device can be further reduced.

When a hole through which the viscous fluid can pass is formed in a part of the bending leaf spring, when the bending leaf spring is compressed, a closed space formed between the viscous fluid storage portion and the bending leaf spring is formed. The viscous fluid present exits through the holes. Therefore, when the bending leaf spring is compressed, the bending leaf spring can be prevented from being deformed in the radial direction, and the closed space can be maintained. Therefore, the gap between the bent leaf spring and the viscous fluid filled chamber can be maintained at a preset gap, and a large viscous resistance can be obtained.

[0013]

First Embodiment FIG. 1 shows a torque converter 1 as a first embodiment of the present invention.
2 is a dynamic model diagram of the cross section. FIG. The torque converter 1 is a mechanism for transmitting torque from a crankshaft (not shown) on the engine side to a main drive shaft 9 of a transmission (not shown).

The torque converter 1 includes three types of impellers,
That is, it is mainly composed of the impeller 3, the turbine 4, and the stator 5. The impeller 3 is a front cover 2 connected to a crankshaft (not shown) on the engine side.
Together with this, it constitutes the hydraulic oil chamber. The turbine 4 is connected to the main drive shaft 9 via a turbine hub 8. The stator 5 is arranged between the inner peripheral portion of the impeller 3 and the inner peripheral portion of the turbine 8.

The lockup clutch 10 is arranged in the space between the front cover 2 and the turbine 4. The lockup clutch 10 is mainly composed of an inertia plate 11, a plurality of coil springs 12, an output side plate 15, and a piston 16. The inertia plate 11 is a disc-shaped member arranged laterally of the front cover 2. The inner peripheral end of the inertia plate 11 has a cylindrical shape protruding toward the transmission,
It is supported by the thrust bearing 13 and the bush 14 so as to be rotatable relative to the front cover 2.
An annular weight 11a is fixed to the outer periphery of the inertia plate 11.

The output side plate 15 is a disk-shaped member whose inner peripheral end is fixed to the turbine hub 8, and annular friction members 15a are fixed to both surfaces of the outer peripheral portion. The piston 16 is a disc-shaped member arranged between the output side plate 15 and the turbine 4, and has an inner peripheral end rotatably and axially movable relative to the turbine hub 8 via a bearing 19. It is supported. Furthermore, the outer peripheral portion of the piston 16 is
Front cover 2 through a plurality of coil springs 12
Is engaged with.

With the above configuration, the friction member 15 between the outer peripheral portion of the inertia plate 11 and the output side plate 15 is formed.
A clutch 50 is formed by a and the outer peripheral portion of the piston 16. A space I is formed between the back surface of the turbine 4 and the piston 16, a space II is formed between the piston 16 and the inertia plate 11, and a space III is formed between the inertia plate 11 and the front cover 2. Has been formed. The space I and the space III communicate with each other on the outer peripheral side. The outer peripheral side of the space II is closed with the piston 16 pressing the friction member 15 a against the output side plate 15. The inner peripheral side of the space II communicates with a third oil passage 48 (described later) that passes through the main drive shaft 9.

FIG. 3 shows a hydraulic control circuit 40 for controlling the hydraulic pressure in the torque converter 1. The hydraulic oil is supplied from the oil pump 41 via the pressure regulator 42 to the torque converter 1 and the lockup control valve 4.
3 and the lockup solenoid 44. First
The oil passage 46 is an oil passage extending from the pressure regulator 42 and supplying hydraulic oil to the impeller 3. The second oil passage 47 is an oil passage for discharging the hydraulic oil flowing from the turbine 4. The third oil passage 48 extends from the lockup control valve 43, further passes through the inside of the main drive shaft 9, and communicates with the space II inside the torque converter 1.

Next, the operation will be described. In the state shown in FIG. 3, the lockup solenoid 44 is off, and the hydraulic fluid is drained from the valve of the lockup solenoid 44. As a result, the oil pressure at the piston head of the lockup control valve 43 is lost, and the piston is pushed to the right side in the figure by the force of the spring to close the drain. In this way, the lock-up control valve 43 causes the hydraulic oil from the pressure regulator 42 to pass through the third oil passage 4
Lead to 8. As a result, the space II in the torque converter 1
The hydraulic pressure acts on the piston 16, and the piston 16 moves to the right in FIG. In this state, the friction member 15a of the output side plate 15 is separated from the inertia plate 11 and the piston 16. That is, the lockup clutch 10 is in the released state. At this time, the weight 11a is in a state of being disconnected from both the input side and the output side.

Next, when the vehicle speed reaches a constant value, the lockup solenoid 44 is turned on by a signal from a vehicle speed sensor (not shown). Then, as shown in FIG. 4, the piston of the lockup control valve 43 is pushed to the left side of the drawing by the operating hydraulic pressure, so that the space I of the torque converter 1 is increased.
The hydraulic oil in I is drained via the third oil passage 48 and further via the lockup control valve 43. Then, the working hydraulic pressure in the space II becomes lower than that in the spaces I and III, and as a result, the piston 16 moves to the left side in FIG. In this state, the friction member 15a of the output side plate 15 is sandwiched between the inertia plate 11 and the piston 16. At this time, as is apparent from FIG. 2, the torque is transmitted via the coil spring 12. In addition, the weight 11
a increases the inertia moment ratio of the output side mechanism to the input side mechanism. As a result, the resonance frequency is lowered to be equal to or lower than the idle speed of the vehicle speed, and the generation of abnormal noises such as gear rattle and muffled noise of the transmission is suppressed during general driving. Second Embodiment A second embodiment shown in FIG. 5 uses a bent leaf spring 18 instead of the coil spring 12 of the first embodiment. Here, only the parts different from the first embodiment will be described, and the description of the same structure will be omitted.

The bent leaf spring 18 is a member for transmitting the torque transmitted from the plate member 31 connected to the front cover 2 to the piston 16. Bending leaf spring 1
As shown in FIG. 6, 8 is a plate-shaped member having a constant width, which is sequentially bent in the longitudinal direction.
Used. The viscous fluid filled chamber is formed in an annular shape by the piston 16 and other plates, and the inside thereof is divided into two chambers. The inner peripheral wall of the viscous fluid filling chamber is formed by the plate member 31. Each bending leaf spring 18 is arranged in an annular shape in each of the two viscous fluid filled chambers.

The bent leaf spring 18 will be described in detail with reference to FIG. As shown in the figure, the bent leaf spring 18 is formed by connecting a plurality of spring elements, which are a ring portion 20 and a lever portion 21, in series. Each spring element has a lever portion 21.
Are connected to each other. The plurality of ring portions 20 are annular bodies having substantially the same diameter, and have a predetermined gap s ₁ between adjacent ring portions 20 in a free state. Ring part 20
The inside of is an open ring portion 23. The open ring portion 23 has a gap s ₂ formed in the free state and the set state,
Lever portions 21 extend outward from both sides of the ring opening portion 23, respectively. The lever portions 21 extend so as to widen their distances toward the outside, and the opposite ring portions 20
The lever portion 21 is continuous with one side.

The width of the bent leaf spring 18 is substantially equal to the width of the viscous fluid filled chamber, and the length in the radial direction is smaller than the length of the viscous fluid filled chamber. When such a bent leaf spring 18 is mounted in the viscous fluid filled chamber, as shown in FIG. 7, a plurality of closed spaces 25 are formed between the outer wall of the piston 16 and the bent leaf spring 18. A hole 24 is formed in a part of the lever portion 21 of the bent leaf spring 18 so as to allow the working oil accumulated in a part of the closed space 25 to flow out. In this embodiment, the holes 24 are formed in the plurality of closed spaces 25 so that the hydraulic oil in the closed spaces 25 flows out every other space.

Further, as shown in FIG. 7, the outer wall of the piston 16 is formed with engaging portions 16a projecting toward the inner peripheral side at two opposing locations. The locking portion 16a locks the ring portion 20 on the outer peripheral side of the bent leaf spring 18. Further, on the outer peripheral portion of the support portion 31a of the plate member 31, locking portions 31a projecting toward the outer peripheral side are formed at two opposing locations. The locking portion 31 a is locked to the ring portion 20 on the inner peripheral side of the bent leaf spring 18. With this configuration,
The torque input to the plate member 31 is the bending leaf spring 1
It is transmitted to the piston 16 via 8. Also, the locking portion 1
The viscous fluid filling chamber is divided into two chambers by 6a and the locking portion 31a.

When the torsional vibration is transmitted to the plate member 31 with the clutch 50 engaged, the bending leaf spring 1
8 repeatedly expands and contracts to damp torsional vibration. Specifically, when the bending leaf spring 18 is compressed, each lever portion 21
And the bending moment acts on the ring portion 20. At this time, the lever portion 21 bends around the ring opening portion 23 as a fulcrum. The bending moment is evenly distributed in the longitudinal direction in the lever portion 21, and elastic energy is dispersed and stored in the plurality of ring portions 20.

The torsion characteristic in this case is that the bent leaf spring 1
It is determined by the torsional rigidity of 8. That is, the ring opening
Gap s 23₂In a small twist angle range with
The outer peripheral portion of the ring portion 20 of the leaf spring 18 is used as a fulcrum to
The bending part 20 and the lever part 21 bend in the same direction, and the torsional rigidity
The sex is small. On the other hand, when the twist angle increases, the gap s ₂
Becomes 0, and the ring part 20 is hit with the open ring part 23 as a fulcrum.
Since torsional energy is stored, the torsional rigidity does not increase.
It

By using such a bent leaf spring,
A large stopper torque can be obtained. When the bending leaf spring 18 expands and contracts in the viscous fluid filling chamber as described above, the working oil flows through the gap between the bending leaf spring 18 and the viscous fluid filling chamber, and the viscous force produces a vibration damping force. This effect will be described with reference to FIG.

As shown in FIG. 7, a plurality of closed spaces 25 are provided.
In the hatched region A, no hole is formed in the lever portion 21 forming the closed space 25. Therefore, when the bending leaf spring 18 expands and contracts, the working oil flows through a small gap between the bending leaf spring 18 and the viscous fluid filled chamber, and a large viscous resistance is generated. On the other hand, in the other region B of the plurality of closed spaces 25,
A hole 24 is formed in the lever portion 21. Therefore,
The hydraulic oil flows through the holes 24, and the viscous resistance decreases.

Here, the power transmission system constituted by the hydraulic oil housed in the viscous fluid-filled chamber and the curved leaf spring 18 is schematically shown in FIG. In FIG. 8, K1 is a spring component formed by the portion of region B in FIG. 7, and K2 is a spring component formed by the portion of region A. Further, C is a viscous resistance generating portion formed by the portion of the area A. In FIG. 8, the viscous force Fc and the spring force Fk are, respectively, Fc = C · dθ / dt dθ / dt: rotational angular velocity Fk = K · θθ: rotational angle displacement, and are not applied to the region A portion. Since the compressible viscous fluid is contained and the gap is small, the spring force and the viscous resistance of the area A are small. That is, Fc >> Fk2. Therefore, the spring component K2 in FIG. 8 can be ignored, and the spring force and the viscous resistance due to the spring component K1 act in series. Therefore, resonance can be reduced.

If the hole 24 is not formed in a part of the bent leaf spring 18, the bent leaf spring 18 is separated from the outer wall of the piston 16 because the working oil is incompressible. Deforms to the circumference. In this case, the gap through which the hydraulic oil flows becomes large, and the desired viscous resistance cannot be obtained,
The power transmission system in which the spring force and the viscous resistance act in series as described above cannot be realized.

In this embodiment, the bent leaf spring 1 is used.
By using No. 8, the axial dimension can be made smaller than that of the conventional coil spring. Further, since both the elastic force and the viscous resistance can be obtained by the viscous fluid filled chamber and the curved leaf spring 18, the torsional vibration can be effectively damped with a very simple structure. In the above embodiment, at the time of setting of the undulated plate spring, had been of clearance s ₂ in the opening portion 23, the gap s ₂ of the opening portion 23 at the time of the set may be 0.

[0032]

In the lockup clutch according to the present invention, since the lockup clutch can be turned on / off and the weight member can be connected / disconnected by hydraulic control, the control can be accurately performed. When the second elastic member is a bent leaf spring, the axial direction of the entire lockup clutch can be shortened.

When the viscous fluid filling chamber is further provided, both functions of the conventional elastic coupling mechanism and the frictional resistance generating mechanism can be realized by the viscous fluid filling chamber and the bent leaf spring, and the apparatus can be further downsized. Can be achieved. When a hole through which the viscous fluid can pass is formed in a part of the bent leaf spring, the clearance between the bent leaf spring and the viscous fluid filled chamber can be maintained at a preset clearance, and a large viscous resistance can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a torque converter as a first embodiment of the present invention.

FIG. 2 is a mechanical model diagram of a torque converter.

FIG. 3 is a hydraulic circuit diagram when lockup is released.

FIG. 4 is a hydraulic circuit diagram during lockup operation.

FIG. 5 is a diagram corresponding to FIG. 1 in the second embodiment.

FIG. 6 is a front view of a bent leaf spring.

FIG. 7 is a front partial cross-sectional view of a viscous fluid filled chamber and a bent leaf spring.

FIG. 8 is a mechanical model diagram of a power transmission system in a bent leaf spring portion.

[Explanation of symbols]

1 Torque converter 3 impeller 4 turbine 10 Lockup clutch 11a weight 16 pistons 12 coil spring 15 Output side plate 40 Hydraulic control circuit

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Claims (5)

(57) [Claims] 1. A lock-up clutch of a torque converter for transmitting torque from an impeller connected to an input side front cover to a turbine connected to an output side member via a fluid, the lock-up clutch comprising: a front cover and a turbine; A weight member arranged between the weight member, a piston member axially movable laterally of the weight member, an elastic member that circumferentially connects the piston member and the front cover, and the weight An output side plate arranged between the member and the piston member and connected to the output side member; and a hydraulic control device for moving the piston member in the axial direction by hydraulically controlling the inside of the torque converter,
Lockup clutch for torque converter with. 2. The lockup clutch for a torque converter according to claim 1, wherein the elastic member is a bent leaf spring. 3. The lock-up clutch for a torque converter according to claim 2, further comprising a viscous fluid filled chamber in which the bent leaf spring is housed. 4. The lockup clutch for a torque converter according to claim 3, wherein said bent leaf spring has a hole through which a viscous fluid passes, in a part thereof. 5. The bent leaf spring is formed by connecting a plurality of spring elements in series, and the spring element includes a ring portion having an open ring portion in a part thereof, and the ring element goes outward from the open ring portion. The lockup clutch for a torque converter according to claim 4, further comprising a pair of lever portions extending so as to be spaced apart from each other.