JPS63219958A - Lockup type automatic transmission - Google Patents

Abstract

PURPOSE:To protect a bearing from damage or abrasion by reducing the pressure difference between a front hydraulic chamber and a converter chamber when a transmission is locked up, thereby preventing application of excessive thrust onto a lockup clutch piston. CONSTITUTION:An impeller cover 5 formed integrally with a pilot boss 19 with a bush 26 being pressure inserted into a turbin hub 8 is born rotatably. Consequently, a turnine runner 3 rotates with relative rotation being produced between the impeller cover and the turbine runner 3 when torque is being converted. Large compulsive force does not function onto a thrush bearing 27 arranged between the impeller cover 5 and the turbine hub 8, even if the compulsive force is produced due to residual unbalance of the entire turbine runner 3. Furthermore, an oil path 24 is provided to the turbine hub 8 and working oil is fed through a bush 26 to the converter chamber 14 of a front hydraulic chamber 18, thereby the hydraulic chamber 18 is always filled with working oil.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to the structure of a lock-up torque converter in an automatic transmission for automobiles, and more specifically, the present invention relates to the structure of a lock-up torque converter in an automatic transmission for an automobile, and more specifically, to prevent forcing force caused by residual unbalance of a turbine runner from being applied to a thrust bearing provided between an impeller cover and a turbine hub. This also relates to preventing deformation of the lock-up clutch and impeller cover.

[Prior art l] Conventionally, a lock-up clutch built into a torque converter has a turbine hub that faces a cylindrical portion provided at the center of the piston of the lock-up clutch, and the inner circumferential surface of the cylindrical portion and the outer circumferential surface of the hub. is slidable and supports the piston of the lock-up clutch so as to be movable in the axial direction. Further, here, an O-ring or an oil seal is inserted into an annular groove formed on the outer periphery of the turbine hub to maintain liquid tightness (see Japanese Patent Publication No. 7866/1983). Conventionally, in this type of torque converter with a lock-up clutch, the turbine hub is fitted into a spline formed on the outer periphery of the input shaft, and engine power is transmitted from the combination of the lock-up 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 prevent the turbine thrust load generated when oil inside the torque converter circulates from the impeller to the stator via the turbine. In such a structure, centering of the impeller cover is achieved by fitting a pilot boss formed at the tip of the impeller into a hole provided inside the crankshaft. On the turbine hub side, the input shaft is rotatably supported via a bushing on the inside of the stator shaft fixed within the transmission case. [Problem to be Solved by the Invention 1] The problem here is that if the turbine hub and the lock-up clutch piston are completely fluid-tight with an O-ring, oil seal, etc., a so-called lock-up state will occur. In this case, a pressure difference is generated between the torque converter chamber and the front hydraulic chamber in front of the lock-up clutch piston. In other words, in the torque converter chamber, when lock-up occurs,
Control hydraulic pressure is fed, and centrifugal hydraulic pressure is generated in the torque converter chamber in accordance with the engine speed, and the sum of the control hydraulic pressure and centrifugal hydraulic pressure acts from behind the lock-up clutch piston. On the other hand, in the lock-up state, the oil pressure in the front hydraulic chamber is reduced to atmospheric pressure via the circuit that drains the oil pan, and during high-speed rotation, the centrifugal oil pressure in the torque converter chamber increases, and the lock-up clutch piston is activated by the impeller. The cover will be pressed under strong pressure. As a result, the lock-up clutch piston and impeller cover are deformed, the adhesion between the clutch fading and the impeller cover is reduced, and the power transmission capacity of the lock-up clutch is insufficient, and local contact between the clutch fading and the There is a problem in that the surface pressure is extremely high, leading to fading, peeling, and damage. Furthermore, due to the above deformation, the cylindrical part of the lock-up piston and the turbine hub become strained, and when the lock-up piston is released, the separation from the impeller cover is not performed smoothly, resulting in a dragging phenomenon. There is a problem in that it causes a lock-up release shock. Therefore, in order to avoid the above deformation within the operating speed range of the engine, the plate thickness of the lock-up clutch piston,
It may be possible to increase the strength of the impeller cover, but in this case, the moment of inertia of the crankshaft system increases, slowing down the engine's engine speed, and impairing running performance. Further, problems such as increased cost arise due to the increased weight of the torque converter. On the other hand, the rotation center of the impeller cover, which is aligned with the crankshaft, does not coincide with that of the other, and eccentricity occurs. Moreover, since the turbine impeller and lock-up clutch piston are usually connected to the turbine hub with rivets, even if the balance adjustment is done on the back of the turbine impeller in order to keep the unbalance door below the allowable value, Even if welding is carried out, it is difficult to suppress the unbalance to zero. In such a state, the lock-up piston is released, so-called vibration occurs when starting, accelerating suddenly, or when releasing the accelerator pedal in the lock-up zone.
In order to release the lock-up from the perspective of sound, a relative rotation difference occurs between the turbine hub and the impeller cover, and this relative rotation difference is maximum when starting from a stall.
A forcing force is generated on the thrust bearing and thrust washer due to the eccentricity of the impeller cover and turbine hub, and
With the -L field of the turbine rotation speed, a forcing force is generated due to the residual unbalance amount, and there is a problem that the thrust bearing and washer are concerned about wear, ICI m, etc. The present invention has been made based on the above circumstances, and is designed to reduce the pressure difference between the front hydraulic chamber and the torque converter chamber during lock-up to prevent excessive thrust pressure from being applied to the lock-up clutch piston. , a lock-up automatic transmission that realizes centering of the input shaft to reduce the effects of unbalanced structures on the turbine hub side and avoid wear and damage to the thrust bearings and thrust washers. This is what we are trying to provide. [Means for solving the problem] For this purpose, the present invention provides an impeller, a turbine runner,
a fluid torque converter consisting of 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 pilot boss integrally connected to the turbine runner. a turbine hub; a lock-up clutch having a circular hole that axially engages the outer periphery of the turbine hub and spline-fits with the turbine hub to rotate integrally with the turbine hub; the lock-up clutch and the impeller; In the lock-up torque converter in which a front hydraulic chamber is formed between the cover and the lock-up clutch, a bearing hole is formed on the sliding side of the lock-up clutch of the turbine hub, a bushing is disposed in the bearing hole, and a bushing is arranged in the bearing hole, and a bushing is arranged in the bearing hole. An integrally formed impeller cover is rotatably supported, an oil passage is formed in the turbine hub, and the front hydraulic chamber and the torque converter chamber are connected to an oil passage formed in the turbine hub. The passageway, the bushing provided on the turbine hub, and the pilot boss pivotally supported by the bushing communicate with each other through a gap.

[Function 1] Based on the above configuration, the present invention press-fits the bushing into the turbine hub and rotatably supports the impeller cover integrally formed with the pilot boss. The turbine runner rotates with a relative rotation difference between the turbine runner and the runner, and even if a force is generated due to the residual unbalance of the entire turbine runner, a large force is exerted on the thrust bearing provided between the impeller cover and the turbine hub. Not affected. Therefore, damage and wear of the bearing can be prevented. Furthermore, an oil passage is provided in the turbine hub, and the configuration is such that the hydraulic oil from the torque converter chamber is supplied to the front hydraulic chamber through the bushing, so that the front hydraulic chamber is always filled with hydraulic oil and the supply flow rate is By configuring the system so that the drain flow rate from the release circuit always decreases, the centrifugal hydraulic pressure generated during engine rotation is almost equal in the torque converter chamber and the front hydraulic chamber.
Only l1ll oil pressure acts on the lock-up clutch piston. Therefore, deformation of the lock-up clutch piston and impeller cover, and insufficient transmission capacity of the lock-up clutch due to deformation are eliminated. [Embodiments] The present invention will be specifically described below based on 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 an engine via an impeller cover 5 and a drive plate 6, which are connected to the impeller 2. Further, the turbine runner 3 is riveted 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 on both sides of the one-way clutch 11,
4a is provided, and an oil groove 4 is provided in the sliding part with the turbine hub 8.
b, and an oil groove 4d is provided between the stator 4 and the bearing 4C that receives the thrust load of the stator 4. The impeller 2, which is driven by the crankshaft 7 of the engine, circulates hydraulic oil filled in the torque converter chamber 14, and this hydraulic oil flows through the impeller 2, the turbine 3, and the stator 4.
By circulating through the flow path, the turbine runner 3 rotates while being torque-increased by the reaction force of the stator 4, and this rotation drives the input shaft 9 via the turbine hub 8, which drives the automatic transmission (not shown). Power is transmitted to On the other hand, the lock-up piston hub 1 is attached to the turbine hub 8.
5 is riveted to the lock-up piston hub 1.
A lock-up clutch piston 16a of the lock-up clutch 1G is slidably spline-fitted to the lock-up clutch piston 5, and a facing 16b is provided on the impeller cover 5 side of the lock-up clutch piston. The lock-up clutch piston 16a has the purpose of alleviating shock when the clutch is engaged and absorbing drive system vibrations and lA noise.
It is equipped with a torsional damper 17. A front hydraulic chamber 18 is formed between the lock-up clutch piston 16a and the impeller cover 5, and is connected to the input shaft 9 through oil passages 20a and 20b formed in the pilot boss 19 of the impeller cover 5. It communicates with the oil passage 21 inside. The oil passage 21 communicates with a control valve (not shown) of a hydraulic control device, and drains the pressure oil in the front hydraulic chamber 18 during lock-up, and releases the lock-up during gear shifting. When this happens, it functions to supply pressure oil to the front hydraulic chamber 18. Further, a hydraulic apply circuit from the hydraulic control device functions to supply pressure oil to the torque converter chamber 14 via an oil passage 23 between the oil pump drive shaft 22 and the intermediate fixed shaft 13. . 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 bushing 26 is press-fitted into the bearing hole 8b. . Further, an oil passage 24 is provided for supplying pressure oil from the torque converter chamber 14 to the front hydraulic chamber 18 via an oil groove 4b provided in the stator collar 4a. The pilot boss 19 has a wheel body 19a forming a concave portion 19b in its middle portion, and the impeller cover 5 is integrally connected to one side of the wheel body 19a by means such as welding. The outer peripheral part 19c of the wheel body 19a is supported by a bushing 2G press-fitted into the bearing hole 8b of the turbine hub 8, and one end part 19d of the pilot boss 19 is supported by a center hole 25 formed at the end of the crankshaft 7. The other end 19e of the pilot boss 19 is rotatably supported by a shaft hole 9a1. : Inserted. A thrust bearing 27 is provided in the concave portion 19b of the wheel body 19a, and receives a thrust load from the turbine hub 8. Further, 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 device configured in this way will be explained. Engagement of the lock-up clutch 1G, mni, is performed according to a lock-up control pattern that takes fuel efficiency, drivability, etc. into consideration. In addition, when the lock-up clutch 16 is engaged, shifting is performed using the lock-up clutch 16.
After the gear shift is completed, lock-up clutch 1 is released again.
6 to reduce shift shock. At the time of sudden start and sudden acceleration, the lock-up clutch 16 is not operated and the torque converter state is entered. Pressure oil is then supplied to the front oil pressure via an oil passage 21 formed in the input shaft 9 and oil passages 20b and 20a formed in the pilot boss 19 from a lock-up pre-release pressure circuit provided in an oil pump cover (not shown). Chamber 8 is filled. On the other hand, pressure oil from the lock-up apply circuit of the oil pump cover (not shown) is supplied to the oil pump drive shaft 22.
An oil passage 23 formed between the inner diameter of the hollow fixed shaft 13 and the hollow fixed shaft 13
The oil is supplied to the torque converter chamber 14 through an oil groove 4d of the thrust collar 4a. In the torque converter state, the lock-up apply pressure is always set lower than the lock-up release pressure, so a hydraulic pressure difference occurs between the front hydraulic chamber 18 and the torque converter chamber 14, and the lock-up clutch piston 16a is connected to the turbine hub. 8. Then, while a relative rotation difference occurs between the impeller cover 5 and the turbine runner 3, the rotation of the turbine runner 3 increases to near the red zone of the engine during full throttle acceleration. Therefore, a forcing force is generated due to the residual unbalance amount of the entire turbine runner 3, but the bush 26 press-fitted into the turbine hub 8, which is integrally formed with the turbine runner 3, moves the turbine runner 3 to the ring of the pilot boss 19. 1
Since the pilot boss 1 is pivotally supported on the impeller cover 5 by 9c, the pilot boss 1 is integrally formed with the impeller cover 5.
A large force is not generated in the thrust bearing 27 provided between the recess 19tl of the turbine hub 8 and the turbine hub 8. Therefore, damage to the thrust bearing 27 or r! It is possible to solve problems such as J. In the lockup state, hydraulic pressure from a lockup release pressure circuit (not shown) is drained from a locktub control valve (not shown). On the other hand, since the structure is such that hydraulic pressure acts from the lock-up control valve (not shown) to the lock-up apply pressure circuit (not shown), the oil passage 23
, the control hydraulic pressure flows into the torque converter chamber 14 through the oil groove 4d, and the inner diameter of the bushing 2G and the pilot boss press-fitted into the turbine hub 8 from the oil passage 24 provided in the turbine hub 8 through the oil groove 4b. 19 rings 19a
It flows into the front hydraulic chamber 18 through the clearance with the outer circumference. Therefore, even if the oil in the front hydraulic chamber 18 is drained from a lock-up control valve (not shown), the drain flow rate from the flow path 21 is slightly larger than the supply flow rate so that the oil is always filled and no pressure is generated. The oil passage 21 of the input shaft 9 is configured so that
It is drained via. Hydraulic pressure controlled by a lock-up control valve (not shown) and centrifugal hydraulic pressure generated during rotation of the torque converter chamber 14 also act on the lock-up piston 1G, and the pressure-receiving area of the lock-up piston 16 is affected by the lock-up apply pressure and the centrifugal hydraulic pressure. On the other hand, centrifugal hydraulic 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 to press the lock-up clutch piston 16a against the impeller cover 5. Therefore, deformation of the impeller cover 5 and the lock-up clutch piston 16a is prevented.

【Effect of the invention】

As described above, according to the present invention, the turbine runner is integrally formed with the impeller cover by the bushing press-fitted into the bearing hole formed in the boss portion of the turbine hub, which is integrally formed with the turbine runner. Since the turbine runner is configured to be pivotally supported by the pilot boss, the force due to residual unbalance of the entire turbine runner is not exerted on the thrust bearing provided between the turbine hub and the pilot boss. Therefore, no damage or wear occurs to the thrust bearing. Furthermore, an oil passage was provided in the turbine hub, and the front hydraulic chamber was filled with oil to prevent the generation of operating pressure.
When the lock-up clutch is locked up, only the hydraulic pressure of the lock-up control valve acts on the lock-up clutch piston, so excessive pressure, that is, the sum of the hydraulic pressure and the centrifugal hydraulic pressure, does not act on the lock-up piston. Deformation of the lock-up piston, impeller cover, etc. is prevented. Furthermore, a seal ring is provided at the location where the other end of the pilot boss is fitted into the shaft hole provided at the end of the input shaft, so that the operating hydraulic pressure of the lock-up control valve is transmitted through the oil passage of the input shaft. This has the effect of preventing water from flowing into the drain circuit.

[Brief explanation of drawings]

The drawing is an enlarged longitudinal sectional side view showing one embodiment of the present invention. 1...torque converter, 2/...impeller, 3...
・Turbine runner, 4... Stator, 5... Impeller cover, 6... Drive plate, 7... Crankshaft, 8... Turbine hub, 9... Input shaft, 10... Outer race , 11... One-way clutch, 12... Inner race, 13... Hollow fixed shaft, 14... Converter, 15... Lock-up piston hub, 16... Lock-up 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, 2G... Bush.

Claims (2)

[Claims] (1) a fluid torque converter consisting of an impeller, a turbine runner, a stator, and a torque converter chamber; an impeller cover integrally connected to the impeller; and a pilot boss integrally connected to the impeller cover;
It has a turbine hub that is integrally coupled with the turbine runner, and a circular hole that is slidably fitted in the outer periphery of the turbine hub in the axial direction, and that is spline-fitted with the turbine hub and rotates integrally with the turbine hub. lock-up clutch and
In a lock-up torque converter in which a front hydraulic chamber is formed between the lock-up clutch and the impeller cover, a bearing hole is formed on the lock-up clutch sliding side of the turbine hub, and a bush is disposed in the bearing hole. A lock-up automatic transmission characterized in that the impeller cover formed integrally with the pilot boss is rotatably supported. (2) An oil passage is formed in the turbine hub, and the front hydraulic chamber and the torque converter chamber are pivotally supported by the oil passage formed in the turbine hub and the bush provided in the turbine hub. The lock according to claim 1, characterized in that the supply flow rate from the bushing gap is communicated with the pilot boss through the gap between the bushing and the pilot boss so that the drain flow rate from the lock-up release pressure circuit is always small. Up-type automatic transmission machine.