Motors: expansible chamber type – Plural relatively movable or rigidly interconnected working... – With means for selectively changing the speed or force...
Patent
1994-05-13
1996-02-06
Ryznic, John E.
Motors: expansible chamber type
Plural relatively movable or rigidly interconnected working...
With means for selectively changing the speed or force...
91534, 91535, 192111A, F16D 2508, F16D 2512
Patent
active
054888956
DESCRIPTION:
BRIEF SUMMARY
This application is a Rule 371 of PCT/US93/02514 filed Sep. 17, 1993.
This invention relates to clutch hydraulic slave cylinders for use with clutch hydraulic actuators, particularly for use with motor vehicle friction clutches.
A problem with hydraulic clutch actuator systems is that as the vehicle clutch plate wears, the hydraulic slave cylinder piston is returned to a different position in the cylinder housing. Therefore the working volume of the slave cylinder must be sufficient to accomodate the changes in actuator fluid volume within the slave cylinder as the piston "at-rest" position changes due to clutch driven plate wear, together with the volume of fluid displacement by the master cylinder when the clutch actuator system is operated.
With the developing trend towards more compact component parts in vehicle engine compartments it may be advantageous to reduce the overall size of a clutch slave cylinder.
The present invention provides a hydraulic slave which is axially compact.
Accordingly there is provided a clutch hydraulic slave cylinder comprising a cylinder body, a primary piston sealingly reciprocable relative to the body and cooperating with the body to form a first fluid chamber within said body, and a secondary piston sealingly reciprocable relative to the primary piston and co operating with the primary piston to form a second fluid chamber, the second fluid chamber being connected to the first fluid chamber through a valve means characterised in that the primary piston is biased by spring means from a fully retracted condition to an "at-rest" condition in which it can exert a pre-load on a clutch bearing, and said valve means is open when the primary piston is in the fully retracted condition and is closed when the primary piston is in the "at-rest" condition.
Preferably the cylinder body has a cylindrical bore therein and the primary piston reciprocates within the bore characterised in that the primary piston has a coaxial bore therein, and the secondary piston reciprocates within the coaxial bore of the primary piston.
Alternatively the cylinder body is an annular body having inner and outer cylindrical walls forming a first fluid chamber therebetween, characterised in that the inner wall extends axially beyond the outer wall and the primary piston is sealingly slideable on the radially outer surfaces of the two walls.
The invention will be described by way of example and with reference to the accompanying drawings in which
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross section through a first embodiment of the invention;
FIG. 1A is a fragmentary view of part of the valve means used in FIG. 1;
FIG. 2 is a longitudinal cross-section through a second embodiment of the invention;
FIG. 3 is a section through an isometric view of the embodiment of FIG. 2;
FIG. 4 is a longitudinal section through a third slave cylinder;
FIG. 5 is a section through yet another embodiment of the invention;
FIG. 6 is a cross-section through yet another embodiment of the invention, and
FIG. 7 is an enlargement of a portion of FIG. 6 showing the valve mechanism .
DETAILED DESCRIPTION
With reference now to FIG. 1 there is illustrated a cylindrical slave cylinder 16 that operates a vehicle clutch through a lever usually pivoted to the gearbox housing.
The slave cylinder 16 has a cylinder body 14 with a cylindrical bore 15 having an end wall at one end and a mouth 19 at the other end. A primary piston 41 is slideable in the bore and is sealed in the bore 15 by a seal 47 to form a first fluid chamber 60 in the closed end of the bore. The first chamber 60 is connected to a source of hydraulic pressure through a conduit 17.
The piston has a coaxial cylindrical extension 21 thereon that extends through the mouth 19 of the bore 15.
An elastomeric boot 53 seals the piston 41 in the mouth 19 of the bore to form a fluid reservoir "V". The seal 47 allows a slight fluid leakage between the fluid chamber 60 and fluid reservoir "V" enclosed by the boot 53. The seal 47 acts as a non-return valve allowing the flow of f
REFERENCES:
patent: 2928246 (1960-03-01), Sjodin
patent: 3474888 (1969-10-01), Carlson
patent: 3828894 (1974-08-01), Crossman
patent: 3940938 (1976-02-01), Durham et al.
patent: 4802559 (1989-02-01), Fourie et al.
patent: 5144878 (1992-09-01), Cadeddu
patent: 5235898 (1993-08-01), Delin et al.
Automotive Products France SA
Germain Lee A.
Milliken Paul E.
Ryznic John E.
LandOfFree
Clutch slave cylinder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Clutch slave cylinder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clutch slave cylinder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2170555