Torque transmitting apparatus

Abstract

A hydrokinetic torque converter with a built-in bypass clutch is provided with an arrangement which regulates the cooling of the clutch at a rate dependent upon the slip between the coaxial driving and driven parts of the clutch, and hence upon the quantity of generated friction heat. The cooling unit for the driving and / or driven part of the clutch can employ, for example, one or more pumps; a supply of a substance which changes its aggregate state from liquid to gaseous or from solid to flowable in response to heating, and vice versa in response to cooling; one or more porous washers in the path for the flow of hydraulic fluid between the customary plenum chambers provided in the housing of the torque converter to move a piston of the driven part of the clutch into and from frictional engagement with the housing; and / or a system of recesses, grooves, channels and / or other passages serving to convey fluid between the chambers at a rate which is higher or highest when the clutch operates with maximum slip. Such rate can decrease to zero when the torque converter is idle or the clutch is fully engaged to operate without slip.

Description

CROSS-REFERENCE TO RELATED CASES[0001] The present application claims the priority of the commonly owned copending German patent application Serial No. 100 20 907.6 filed Apr. 28, 2000. The disclosure of the above-referenced German patent application, as well as that of each US and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.[0002] The present invention relates to improvements in torque transmitting apparatus, and more particularly to improvements in hydrokinetic torque converters of the type often utilized in the power trains of motor vehicles, e.g., to transit torque between the output element of a prime mover (such as a crankshaft or a camshaft of a combustion engine) and the input shaft of a change-speed transmission.[0003] A torque converter of the character to which the present invention pertains normally comprises a rotary housing which is driven by the prime mover and drives a vaned pum...

AI Technical Summary

Benefits of technology

"The present invention provides a hydrokinetic torque converter with a cooling system that can withdraw heat at a rate that prevents damage to sensitive parts and can be incorporated into existing types of torque converters without significantly changing their construction or operation. The cooling system includes a pump, a turbine, a bypass clutch, and a fluid-operated bypass clutch. The bypass clutch can be designed to operate with slip and can be set up to withdraw excess heat at a rate proportional to the quantity of surplus heat. The invention also provides a novel and improved method of removing heat from the bypass clutch without affecting the operation of the bypass clutch. The invention also includes a novel and improved friction lining for use in the bypass clutch and a fluid agitating device for use in a torque converter. The cooling system can be incorporated into existing torque converters without significantly changing their construction or operation."

Problems solved by technology

Partial engagement of the bypass clutch involves a slip of the piston relative to the housing and / or vice versa, and such slip results in the generation of heat in such quantities that the fluid medium in the housing of the torque converter is not always capable of absorbing excess heat.

Excessive heating of friction linings forming part of the bypass clutch can entail damage to and frequently rapid destruction of the friction linings; in addition, overheating can adversely influence the hydraulic fluid in the housing of the torque converter.

Abrupt full engagement of the bypass clutch, i.e., without slip, is likely to be even more damaging to the torque converter and can also adversely affect the comfort to the occupant(s) of the motor vehicle.

Thus, an abrupt transition from disengagement to full engagement of the bypass clutch can be a cause of discomfort to the occupant(s).

Such requirements cannot be met, or cannot be adequately satisfied, by presently known torque converters.

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