friction fit

Abstract

A friction engagement device, comprising a forward clutch (5) and a clutch actuating assembly (6) for controlling the coupling and releasing actions of the forward clutch (5), wherein the clutch actuating assembly (6) has: a hydraulic piston (61) ), connecting pressure piston chamber (62), split ring (64), diaphragm spring (65), ball locking mechanism (BL). The diaphragm spring (65) applies elastic coupling force to the forward clutch (5) on the clutch side of the hydraulic piston (61). The ball lock mechanism (BL) acts on the engagement pressure piston chamber (62) by applying engagement pressure to the position where the forward clutch (5) is engaged by the elastic engagement force, and restricts the movement of the hydraulic piston (61) in the release direction. After the movement of the hydraulic piston (61) is restricted, even if the engagement pressure of the engagement pressure piston chamber (62) is discharged, the movement restriction of the hydraulic piston (61) in the release direction is maintained.

Description

technical field [0001] The invention relates to a frictional engagement element (multi-plate clutch or multi-plate brake, etc.) applied to an automatic transmission (including CVT, step-AT (step-AT)), etc. A hydraulic friction engagement device is used for the control. Background technique [0002] Conventionally, a friction engagement device including a friction engagement element, a hydraulic piston, and a return spring is known as a friction engagement device of an automatic transmission. In this friction engagement device, the coupling oil pressure of the elastic force of the return spring acts to perform the coupling action of the frictional engagement element, and the elastic force of the return spring realized by draining the coupling oil pressure performs the release action of the frictional engagement element ( For example, refer to Patent Document 1). [0003] Patent Document 1: (Japanese) Unexamined Patent Publication No. 7-12221 [0004] However, in the existi...

AI Technical Summary

Problems solved by technology

Therefore, there is a problem that much energy is consumed in the engagement and release of the frictional engagement elements, resulting in poor fuel consumption performance in the case of an engine vehicle, and deterioration in power consumption performance in the case of an electric vehicle. Difference

[0005] That is, while the frictional engagement elements are in the engaged and maintained state, in order to continue to create the engaged and maintained pressure, the engine or the electric motor needs to continuously drive the oil pump, and the driving torque loss of the oil pump increases.

In addition, while the frictional engagement elements are in the engagement holding state, the engagement holding pressure acts on the seal ring set on the relative rotating part in the middle of the oil pressure path introducing the engagement holding pressure, so the friction loss of the seal ring portion increases.

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