Power plants – Pressure fluid source and motor – Pulsator
Reexamination Certificate
1999-08-20
2001-03-06
Ryznic, John E. (Department: 3745)
Power plants
Pressure fluid source and motor
Pulsator
Reexamination Certificate
active
06195994
ABSTRACT:
The present invention relates to a master cylinder with hydraulic reaction, comprising: a cylindrical body delimiting a variable-volume working chamber full of brake fluid; a main piston mounted to slide selectively in the working chamber in a first axial direction to reduce the volume of this working chamber; an axial bore pierced in the main piston and delimiting a variable-capacity reaction chamber subjected to a variable pressure; a reaction piston closing the reaction chamber and mounted to slide selectively in the axial bore in the first axial direction to reduce the capacity of the reaction chamber; and a non-return valve selectively allowing fluid to flow from the reaction chamber towards the working chamber.
A master cylinder of this type is incorporated into the braking device described in the prior art in Patent EP-0,662,894.
Such a braking device has the advantage of optimizing the intensity of the braking force in the event of an abrupt application of the brakes, particularly by delaying the rise in reaction force opposing this braking force.
More recently, in brake system design, there has developed a preoccupation with being able to vary the reaction force in inverse proportion to the braking effort, so as to optimize the use of the braking energy exerted by the driver in the event of intense braking.
The present invention falls within this context and is intended to provide a master cylinder with hydraulic reaction that is of simple structure and offers this feature.
To this end, the master cylinder of the present invention, which in other respects is in accordance with the generic definition given in the above preamble, is essentially characterized in that it comprises a stepped piston mounted so that it can float in the axial bore between the reaction chamber and the working chamber, and sliding in the first axial direction against a spring whose length decreases, as the variable pressure increases, in that the stepped piston delimits in a leaktight fashion, within the axial bore, an annular chamber subjected to a low pressure, and in that the non-return valve is installed on an axial drilling passing through the stepped piston, this non-return valve being open or closed according to whether the length of the spring is at least equal to a predetermined minimal distance, or less than this minimal distance.
The stepped piston preferably has a section of smaller relative diameter, facing towards the working chamber, and a section of larger relative diameter, facing towards the reaction chamber.
In an advantageous embodiment of the invention, the non-return valve comprises a valve seat defined on a shoulder of the axial drilling in the stepped piston, a shut-off member urged elastically towards the seat in a second axial direction which is the opposite of the first axial direction, and a needle which is stationary with respect to the main piston, and one end of which points in the first axial direction for selectively moving the shut-off member away from the valve seat when the length of the spring is at least equal to the predetermined minimal distance.
REFERENCES:
patent: 5735124 (1998-04-01), Cords et al.
patent: 5921084 (1999-07-01), Gautier et al.
patent: 6076351 (2000-06-01), Sacristan
Comstock Warren
McCormick Jr. Leo H
Robert & Bosch GmbH
Ryznic John E.
LandOfFree
Master cylinder with hydraulic reaction operating with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Master cylinder with hydraulic reaction operating with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Master cylinder with hydraulic reaction operating with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2472684