JPH0733861B2 - Lock-up automatic transmission - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a structure of a lock-up type torque converter in an automatic transmission for an automobile, and more specifically, does not exert a forcing force generated by a residual unbalance of a turbine runner on a thrust bearing provided between an impeller cover and a turbine hub. The present invention also relates to prevention of deformation of the lockup clutch and the impeller cover.

[Prior art]

Conventionally, a lockup clutch with a built-in torque converter has a turbine hub fitted to a cylindrical part provided at the center of the piston of the lockup clutch, and the inner peripheral surface of the cylindrical part and the outer peripheral surface of the hub are slidable. And the piston of the lockup clutch is supported so as to be movable in the axial direction. Further, here, an O-ring and an oil seal are put in an annular groove formed on the outer periphery of the turbine hub to maintain liquid tightness (see Japanese Patent Publication No. 59-7866). Further, conventionally, in this type of torque converter with a lockup clutch, a turbine hub is fitted to a spline formed on the outer periphery of the input shaft to transmit engine power from a combination of the lockup clutch and the turbine impeller. Is going. A thrust bearing or a thrust washer is provided between the turbine hub and the impeller cover to receive the turbine thrust load generated when the oil inside the torque converter chamber circulates from the impeller to the stator via the turbine. In such a structure, the impeller cover is centered by fitting the pilot boss formed at the tip of the impeller into the hole provided inside the crankshaft. The turbine hub side has a type in which an input shaft is rotatably supported by a bush with respect to the inside of a stator shaft fixed in the transmission case.

[Problems to be Solved by the Invention]

The problem here is that when the space between the turbine hub and the lockup clutch piston is kept completely liquid-tight by an O-ring, an oil seal, etc., in the so-called lockup state, the torque converter chamber and the lock A pressure difference occurs between the front clutch and the front hydraulic chamber on the front side of the up clutch piston. That is, when the torque converter room is locked up,
The control oil pressure is pumped, and centrifugal oil pressure according to the engine speed is generated in the torque converter chamber, and the sum of the control oil pressure and the centrifugal oil pressure acts from the rear of the lockup clutch piston. On the other hand, in the front hydraulic chamber, the hydraulic pressure is reduced to the atmospheric pressure via the circuit that drains the oil pan in the lockup state.Therefore, the centrifugal hydraulic pressure in the torque converter chamber rises at high speed rotation, and the lockup clutch piston operates as an impeller. It will be pressed against the cover under strong pressure. As a result, the lockup clutch piston and the impeller cover are deformed, the adhesion between the clutch fading and the impeller cover is reduced, the power transmission capacity of the lockup clutch is insufficient, or the local contact of the clutch fading causes There is a problem that the surface pressure of the part rises extremely, leading to peeling and damage of fading. In addition, due to the above deformation, twisting occurs between the cylindrical portion of the lock-up piston and the turbine hub, and when the lock-up is released, separation from the impeller cover is not performed smoothly and a drag phenomenon occurs, resulting in a shift. There is a problem of causing lock-up release shock. Therefore, in order to avoid the above deformation within the range of engine rotation speed, the plate thickness of the piston of the lockup clutch,
It is conceivable to increase the strength of the impeller cover, but in this case, the moment of inertia of the crankshaft system becomes large, the engine blow-up becomes dull, and the running performance is impaired. Further, there is a problem that the cost of the torque converter is increased due to the increase in weight of the torque converter. On the other hand, the center of rotation does not coincide with the side of the impeller cover that is aligned with the crankshaft, causing eccentricity. In addition, the turbine hub usually has a structure in which the turbine impeller and the lockup clutch piston are riveted to each other, so even if the unbalance amount is kept below the allowable value, balance adjustment is performed on the back of the turbine impeller. Even if welding is performed, it is difficult to keep the unbalance amount to zero. In such a state, the lockup piston is released, so-called at the time of starting or sudden acceleration and when the accelerator pedal is released in the lockup zone. A relative rotation difference occurs between the impeller cover and the stall starter, which maximizes the relative rotation difference.Therefore, thrust bearings and thrust washers are forced by the eccentricity of the impeller cover and turbine hub, and the turbine rotation is further increased. As the number increases, a forced force is generated due to the residual unbalance amount, and there is a concern that the thrust bearing and the washer may be worn or damaged. The present invention has been made based on the above circumstances. At the time of lockup, the pressure difference between the front hydraulic chamber and the torque converter chamber is reduced so that an excessive thrust pressure is not applied to the lockup clutch piston. Along with the centering of the input shaft, even if there is an imbalance in the structure on the turbine hub side, this effect is mitigated and the thrust bearing and thrust washers are prevented from wear and damage. It is intended to provide a transmission.

[Means for solving problems]

To this end, the present invention provides an impeller, turbine runner,
A fluid torque converter including a stator and a torque converter chamber, an impeller cover integrally connected to the impeller, a pilot boss integrally connected to the impeller cover, and a turbine runner. A turbine hub, a lock-up clutch that has a circular hole that slidably fits the outer circumference of the turbine hub in the axial direction, and a spline-fitted rotation with the turbine hub that rotates integrally with the turbine hub; In a lock-up torque converter having a front hydraulic chamber formed between the impeller cover and a turbine hub, a bearing hole is formed on the sliding side of the lock-up clutch of the turbine hub, and a bush is arranged in the bearing hole. The impeller cover that is integrally formed with the An oil passage is formed in the turbine hub, and the front hydraulic chamber and the torque converter chamber are formed in the turbine hub, the oil passage formed in the turbine hub, the bush provided in the turbine hub, and the pilot pivotally supported by the bush. It is configured to communicate with each other through a gap with the boss.

[Action]

Based on the above configuration, according to the present invention, the bush is press-fitted into the turbine hub, and the impeller cover integrally formed with the pilot boss is rotatably supported, so that in the torque converter state, the impeller cover and the turbine runner are always opposed to each other. The turbine runner rotates while a rotation difference occurs, and even if a force due to the residual unbalance amount of the entire turbine runner is generated, a large force is not applied to the thrust bearing provided between the impeller cover and the turbine hub. Therefore, damage and wear of the bearing can be prevented. Further, since the oil passage is provided in the turbine hub and the hydraulic oil in the torque converter chamber is supplied to the front hydraulic chamber via the bush, the front hydraulic chamber is always filled with the hydraulic oil and the supply flow rate is By configuring so that the drain flow rate from the release circuit is always small, the centrifugal hydraulic pressure generated during engine rotation is almost equal in the torque converter chamber and the front hydraulic chamber,
Only the control oil pressure acts on the lockup clutch piston. Therefore, the deformation of the lock-up clutch piston and the impeller cover and the shortage of the transmission capacity of the lock-up clutch due to the deformation are eliminated.

【Example】

Hereinafter, the present invention will be specifically described based on the illustrated embodiments. The torque converter 1 includes an impeller 2, a turbine runner 3, and a stator 4. The impeller 2 is connected to a crankshaft 7 of the engine via an impeller cover 5 and a drive plate 6 which are connected to the impeller 2. The turbine runner 3 is tacked to the turbine hub 8, and the input shaft 9 is spline-fitted to the turbine hub 8. The stator 4 is attached to a hollow fixed shaft 13 integrally formed with an oil pump cover (not shown) via an outer race 10, a one-way clutch 11, and an inner race 12 which are constituent members of a one-way clutch. Stator collars 4a and 4a are provided on both sides of the one-way clutch 11, an oil groove 4b is provided in a sliding portion with the turbine hub 8, and an oil groove 4d is provided between the stator 4 and a bearing 4c that receives a thrust load of the stator 4. ing. The impeller 2 driven by the crankshaft 7 of the engine rotates the hydraulic oil filled in the torque converter chamber 14, and this hydraulic oil impeller 2, turbine 3, stator 4
The turbine runner 3 rotates while being subjected to a torque increasing action by the reaction force of the stator 4 by the circulation of the flow path of the above, this rotation drives the input shaft 9 via the turbine hub 8, and the automatic transmission (not shown). Power is transmitted to (No.). On the other hand, the turbine hub 8 has a lockup piston hub 15
The lock-up clutch hub 16 is slidably fitted with the lock-up clutch piston 16a of the lock-up clutch 16 onto the lock-up piston hub 15, and the locking-up clutch piston 15 is faced to the impeller cover 5 side.
16b is provided. The lock-up clutch piston 16a absorbs shock when the clutch is engaged,
A torsional damper 17 is provided for the purpose of absorbing vibration and noise of the drive system. A front hydraulic chamber 18 is formed between the lock-up clutch piston 16a and the impeller cover 15, and the front hydraulic chamber 18 is formed through oil passages 20a and 20b formed in a pilot boss 19 of the impeller cover 5. It communicates with the oil passage 21 inside. Then, the oil passage 21 is
It communicates with a control valve (not shown) of the hydraulic control device, and drains the pressure oil in the front hydraulic chamber 18 at the time of lockup, and the front hydraulic pressure at the time of releasing the lockup during gear shifting. It serves to supply pressure oil to the chamber 18. Further, the hydraulic apply circuit from the hydraulic control device is provided with an oil passage between the oil pump drive shaft 22 and the intermediate fixed shaft 13.
The pressure oil is supplied to the torque converter chamber 14 via 23. Further, the turbine hub 8 is formed with a boss portion 8a on which the lock-up clutch piston 16a slides, a bearing hole 8b is formed in the boss portion 8a, and a bush 26 is formed in the bearing hole 8b.
Has been press-fitted. Further, an oil passage 24 is provided for supplying the pressure oil in the torque converter chamber 14 to the front hydraulic chamber 18 via the oil groove 4b provided in the stator collar 4a. The pilot boss 19 forms a wheel body 19a having a recessed portion 19b in an intermediate portion, and the impeller cover 5 is integrally coupled to one side surface of the wheel body 19a by means such as welding. Ring 19
The outer peripheral portion 19c of a is pivotally supported by a bush 26 press-fitted into a bearing hole 8b of the turbine hub 8, and one end portion 19d of the pilot boss 19 is pivotally supported by a center hole 25 formed at the end of the crankshaft 7. The other end of the pilot boss 19
19e is a shaft hole 9a provided at the end of the input shaft 9.
Has been inserted into. A thrust bearing 27 is provided in the recess 19b of the wheel body 19a and receives the thrust load from the turbine hub 8. A seal ring 28 is provided to prevent hydraulic oil from leaking from the oil passage 21 to the thrust bearing 27 side through the clearance between the shaft hole 9a provided at the end of the input shaft 9 and the other end 19e of the pilot boss 19. ing. Next, the operation of the apparatus thus configured will be described. Engagement / disengagement of the lockup clutch 16 is performed according to a lockup control pattern in consideration of fuel consumption, drivability, and the like. Further, in gear shifting while the lock-up clutch 16 is engaged, the lock-up clutch 16 is released, and after the gear shift is completed, the lock-up clutch 16 is engaged again to reduce gear shift shock. At the time of sudden start and sudden acceleration, the lockup clutch 16 is not operated and the torque converter state is entered. And the pressure oil is
An oil passage 21 formed in the input shaft 9 and oil passages 20b, 20 formed in the pilot boss 19 from a lock-up release pressure circuit provided in an oil pump cover (not shown).
The front hydraulic chamber 8 is filled via a. On the other hand, the pressure oil from the lock-up apply circuit of the oil pump cover (not shown) passes through the oil groove 4d of the thrust collar 4a from the oil passage 23 formed between the inner diameter of the oil pump drive shaft 22 and the hollow fixed shaft 13. Through torque converter room
Supplied to 14. In the torque converter state, the lock-up apply pressure is always lower than the lock-up release pressure, and the hydraulic pressure is set. Therefore, a hydraulic pressure difference occurs between the front hydraulic chamber 18 and the torque converter chamber 14, and the lock-up clutch piston 16
The a contacts the turbine hub 8. Since there is no relative rotation difference between the impeller cover 5 and the turbine runner 3, the turbine runner 3 will rotate up to near the red zone of the engine during full-open acceleration. Therefore, a forced force is generated due to the residual unbalance amount of the turbine runner 3 as a whole, but the push-fitted into the turbine hub 8 formed integrally with the turbine runner 3 is pressed.
Since the turbine runner 3 is pivotally supported on the impeller cover 5 by the wheel body 19c of the pilot boss 19 at 26, the concave portion of the pilot boss 19 formed integrally with the impeller cover 5
A large forcing force does not occur in the thrust bearing 27 provided between the 19b and the turbine hub 8. Therefore, problems such as damage and wear of the thrust bearing 27 can be solved. In the lockup state, the hydraulic pressure of the lockup release pressure circuit (not shown) is drained from the lockup control valve (not shown). On the other hand, since the lock-up control valve (not shown) is configured such that hydraulic pressure acts on the lock-up apply pressure circuit (not shown), the oil passage 23,
The control hydraulic pressure flows into the torque converter chamber 14 via the oil groove 4d, and the bush 26 press-fitted into the turbine hub 8 from the oil passage 24 provided in the turbine hub 8 via the oil groove 4b.
Flows into the front hydraulic chamber 18 through a clearance between the inner diameter of the pilot boss 19 and the outer peripheral portion of the wheel body 19a of the pilot boss 19. Therefore, even if the oil in the front hydraulic chamber 18 is drained from a lock-up control valve (not shown), the oil is always filled and the flow passage is adjusted so that pressure is not generated.
It is configured so that the drain flow rate from 21 is slightly large, and the oil is drained via the oil passage 21 of the input shaft 9. The lockup piston 16 is a hydraulic and torque converter chamber 14 controlled by a lockup control valve (not shown).
The centrifugal oil pressure generated during the rotation of the lockup piston 16 also acts on the pressure receiving area of the lockup piston 16 by the sum of the lockup apply pressure and the centrifugal oil pressure, while the centrifugal oil pressure also acts on the front hydraulic chamber. Therefore, only the hydraulic pressure of a lock-up control valve (not shown) acts on the lock-up piston 16, and the lock-up clutch piston is applied to the impeller cover 5.
Press 16a. Therefore, the deformation of the impeller cover 5 and the lockup clutch piston 16a is prevented.

【The invention's effect】

As described above, according to the present invention, the turbine runner is formed integrally with the impeller cover by the bush press-fitted into the bearing hole formed in the boss portion of the turbine hub integrally formed with the turbine runner. Since it is configured to be supported by the pilot boss, the forced force by the residual unbalance amount of the entire turbine runner is not exerted on the thrust bearing provided between the turbine hub and the pilot boss. Therefore, the thrust bearing is not damaged or worn. In addition, an oil passage is provided in the turbine hub to fill the oil so that no operating pressure is generated in the front hydraulic chamber.
When the lockup clutch is locked up, only the operating oil pressure of the lockup control valve acts on the lockup clutch piston, so excessive pressure, that is, the sum of the operating oil pressure and centrifugal oil pressure, does not act on the lockup piston. The deformation of the lock-up piston, impeller cover, etc. is prevented. Furthermore, since the seal ring is provided at the position where the other end of the pilot boss is inserted into the shaft hole provided at the end of the input shaft, the operating oil pressure of the lock-up control valve passes through the oil passage of the input shaft. It has an effect that it is prevented from flowing out to the drain circuit.

[Brief description of drawings]

The drawing is an enlarged vertical side view showing an embodiment of the present invention. 1 ... Torque converter, 2 ... Impeller, 3 ... Turbine runner, 4 ... Stator, 5 ... Impeller cover,
6 ... Drive plate, 7 ... Crank shaft, 8 ... Turbine hub, 9 ... Input shaft, 10 ... Outer race, 11 ... One way clutch, 12 ... Inner race, 13 ... Hollow fixed shaft, 14 ... … Converter room, 15 ……
Lockup piston hub, 16 …… Lockup clutch piston, 17 …… Damper, 18 …… Front hydraulic chamber, 19
...... Pilot boss, 20a, 20b ...... Oil passage, 21 ...... Oil passage, 22 ...... Oil pump drive shaft, 23,24 ...... Oil passage, 25 ...... Center hole, 26 ...... Bush.

Claims (2)

[Claims] 1. A fluid torque converter comprising an impeller, a turbine runner, a stator and a torque converter chamber,
An impeller cover integrally connected to the impeller,
A pilot boss integrally connected to the impeller cover, a turbine hub integrally connected to the turbine runner, and a circular hole for axially slidably fitting the outer periphery of the turbine hub are provided. A lock-up clutch that spline-fits with a turbine hub and rotates integrally, and a lock-up torque converter that forms a front hydraulic chamber between the lock-up clutch and the impeller cover. A lock characterized in that a bearing hole is formed on the clutch sliding side, a bush is disposed in the bearing hole, and an impeller cover integrally formed with the pilot boss is rotatably supported. Up-type automatic transmission. 2. An oil passage is formed in the turbine hub, and the front hydraulic chamber and the torque converter chamber are connected to each other.
The supply flow rate from the bush gap through the oil passage formed in the turbine hub and the gap between the bush provided in the turbine hub and the pilot boss pivotally supported by the bush is the drain from the lock-up release pressure circuit. The lock-up type automatic transmission according to claim 1, characterized in that the communication is configured so that the flow rate is always small.