# US 2013/0153359 A1 · Clutch control apparatus for vehicle

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- Number: US 2013/0153359 A1
- Document ID: US20130153359A1
- Status: Published application
- Kind: A1
- Application number: 13/818,523
- Filed: 2011-08-30
- Published: 2013-06-20
- Earliest claimed: 2010-09-21
- Assignees: Nissan Motor Co., Ltd.
- Inventors: Makoto Ogata; Akira Suwabayashi
- Web page: https://patentgrep.com/patent/US20130153359A1

## CPC

- F16D 25/04: in which the fluid actuates an elastic clutching, {i.e. elastic actuating} member, e.g. a diaphragm or a pneumatic tube (F16D25/02 takes precedence; coupling using a pneumatic tube F16D3/82)
- F16D 25/087: {the clutch being actuated by the fluid-actuated member via a diaphragm spring or an equivalent array of levers (F16D25/085, F16D25/086 take precedence)}
- F16D 48/066: {Control of fluid pressure, e.g. using an accumulator (F16D48/062, F16D48/068 take precedence)}
- F16D 2500/1026: Hydraulic
- F16D 2500/501: Relating the actuator
- F16D 2500/70406: Pressure
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES

## Abstract

Taught herein is a clutch control apparatus that suppresses oil leakage from a seal member of a hydraulic cylinder even when vibration occurs, without enhancing sealability of the seal member per se. The clutch control apparatus includes normally-closed first clutch, a hydraulic cylinder, a piston, a lip seal and a pressure holding control section. The first clutch is disposed between an engine and driving wheels and is held in engagement by an elastic force applied to the first clutch CL1 by a diaphragm spring. The lip seal is disposed on the piston and enhances sealability between the piston and a housing slide surface in accordance with an increase in hydraulic pressure in the piston chamber. When the first clutch is engaged, the pressure holding control section applies a hydraulic pressure to retain the sealability of the lip seal to the piston chamber while maintaining engagement of the first clutch.

## Claims

### Claim 1

A clutch control apparatus for a vehicle, comprising:
a normally-closed clutch disposed between a driving power source and driving wheels, the clutch being held in engagement by an elastic force applied to the clutch by an elastic member;
a hydraulic cylinder serving as a hydraulic actuator of the clutch, the hydraulic cylinder disengaging the clutch by a hydraulic force overcoming the elastic force of the elastic member;
a piston slidably disposed in a piston housing of the hydraulic cylinder, the piston having one end to which the elastic force of the elastic member is applied and the other end to which a hydraulic pressure in a piston chamber is applied;
a seal member disposed on the piston, the seal member enhancing sealability between the piston and a housing slide surface of the piston housing in accordance with an increase in the hydraulic pressure in the piston chamber; and
a pressure holding control section that, upon engagement of the clutch, applies the hydraulic pressure to retain the sealability of the seal member to the piston chamber of the hydraulic cylinder while maintaining an engagement condition of the clutch.

### Claim 2 (depends on 1)

The clutch control apparatus as claimed in claim 1, wherein the elastic member is a diaphragm spring, the diaphragm spring pressing the piston toward a side of the piston chamber by a centrifugal force that acts on the diaphragm spring upon rotation of the driving power source in the engagement condition of the clutch; and
wherein the pressure holding control section applies the hydraulic pressure to the piston chamber such that a press stroke position of the piston pressed by the diaphragm spring is in a range in which the engagement condition of the clutch is maintained.

### Claim 3 (depends on 2)

The clutch control apparatus as claimed in claim 2, wherein the pressure holding control section applies the hydraulic pressure to the piston chamber when a rotation speed of the driving power source becomes not less than a predetermined threshold value.

### Claim 4 (depends on 2)

The clutch control apparatus as claimed in claim 2, further comprising:
a piston stroke position detecting device that detects a stroke position of the piston; and
wherein the pressure holding control section determines a stroke position of the piston in a rotation-stop engagement condition of the clutch as a target stroke position and carries out feedback control so as to conform an actual stroke position of the piston to the target stroke position.

### Claim 5 (depends on 2)

The clutch control apparatus as claimed in claim 2, wherein the seal member is a lip seal that is mounted on an outer circumferential surface of the piston in contact with the housing slide surface, the lip seal having a V-shape in cross section that is opened toward the piston chamber, the seal member expanded by the hydraulic pressure being applied to an open side of the seal member.