Load responsive pressure modulating valve device for use in a brake system of a vehicle
AssigneeSumitomo Electric Industries, Ltd.
InventorsKaname Doi, Hiroaki Nagara
Life of this patent
Estimating the term…
Abstract
A load responsive pressure modulating valve device for use in a brake system of a vehicle is so constructed that the starting pressure for the pressure modulating operation is controlled by a specific valve operated by a partial pressure of the input hydraulic brake pressure. The device is capable of distributing the hydraulic brake pressure corresponding to a transient weight transfer from rear wheels of the vehicle to front ones caused by the braking operation, to the front and rear brakes by varying the starting pressure in response to load and deceleration of the vehicle.
Claims10
A load responsive pressure modulating valve device for use in a brake system of a wheeled vehicle, having front and rear wheel braking means, said device provided with means for modulating a hydraulic brake pressure supplied to the front and rear wheel braking means so as to distribute the hydraulic brake pressure corresponding approximately to a weight transfer in the vehicle caused by the braking operation to said front and rear wheel braking means, whereby the hydraulic brake pressure supplied to said rear wheel braking means is reduced in comparison with that supplied to said front wheel braking means, comprising:
- means for modulating said hydraulic brake pressure so that a starting pressure for directing the pressure modulating operation thereto is controlled by a partial pressure of said hydraulic brake pressure;
- means for detecting the deceleration of the vehicle disposed in a branch circuit of the hydraulic brake pressure circuit including either of said front and rear wheel braking means, said detecting means being movable in response to a predetermined deceleration of the vehicle corresponding to the hydraulic brake pressure for a light load condition;
- means disposed in a branch circuit of the hydraulic brake pressure circuit including either of said front and rear wheel braking means for separating said partial pressure of said hydraulic brake pressure in response to the displacement of said deceleration detecting means in order to apply said partial pressure to the control of said starting pressure;
- and means disposed in a branch circuit of the hydraulic brake pressure circuit including either of said front and rear wheel braking means for sensing and controlling the hydraulic brake pressure which increases in proportion to said predetermined deceleration in response to an increase of a value of the hydraulic brake pressure required for generating said predetermined deceleration of the vehicle by utilizing characteristics that said pressure value for generating said predetermined deceleration speed increases in proportion to an increase of a load of the vehicle, whereby the hydraulic brake pressure matching the weight transfer caused by the braking operation under any load condition of the vehicle is distributed to said front and rear wheel braking means, respectively.
A load responsive pressure modulating valve for use in an hydraulic braking system of a wheeled vehicle having front and rear hydraulically actuated braking means comprising:
- a. a housing having a bore connected to a master cylinder and the rear braking means so as to transmit hydraulic braking pressure from said master cylinder to said rear wheel brake system.
- b. a plunger slidably mounted in said bore to modulate the hydraulic braking pressure supplied to the rear braking means by reducing the hydraulic braking pressure when a predetermined value of starting pressure is reached,
- c. a chamber in said housing connected to one end of said bore, and
- d. a differential piston having different areas on opposite sides thereof so that equal pressures will cause the piston to move slidably mounted in said chamber to generate a load responsive pressure which is supplied to one end of said plunger to vary the predetermined value of the starting pressure at which the modulating operation begins.
A load responsive pressure modulating valve for use in an hydraulic braking system of a wheeled vehicle having front and rear hydraulically actuated braking means comprising:
- a. a housing having a bore connected to a master cylinder and the rear braking means so as to transmit hydraulic braking pressure from said master cylinder to said rear wheel brake system.
- b. a plunger slidably mounted in said bore to modulate the hydraulic braking pressure supplied to the rear braking means by reducing the hydraulic braking pressure when a predetermined value of starting pressure is reached,
- c. a chamber in said housing connected to one end of said bore, and
- d. a check valve located in said chamber which closes when a pressure value therein is less than the pressure value in the master cylinder, and opens when the former is greater than the later, wherein said check valve is a cup seal mounted around said plunger.
Dependencies are inferred from the claim text.