Hydraulic circuit having a rotary type pump and brake apparatus for a vehicle provided with the same

A brake apparatus for a vehicle comprising:

• a brake fluid pressure producing device for producing brake fluid pressure at a depressing stroke of a brake pedal in response to braking operation of an operator;
• a wheel braking force generating device for generating wheel braking force using said brake fluid pressure;
• a first conduit connecting said wheel braking force generating device to said brake fluid pressure producing device;
• a pressure control device dispose in said first conduit for alternately increasing, holding, and reducing said brake fluid pressure applied to said wheel braking force generating device;
• a reservoir for accumulating brake fluid by communicating with said wheel braking force generating device through said pressure control device when said brake fluid pressure applied to said wheel braking force generating device is reduced to eliminate a tendency for a wheel to be locked;
• a second conduit connecting said reservoir to said first conduit on a side of said brake fluid pressure producing device rather than said pressure control device;
• a rotary type pump disposed in said second conduit for taking in said brake fluid accumulated in said reservoir and discharging into said first conduit, the rotary type pump producing a wheel cylinder pressure higher than a master cylinder pressure at the depressing stroke of the brake pedal;
• a differential pressure maintaining device provided in said first conduit between said brake fluid pressure producing device and a connection point of said second conduit to said first conduit, for maintaining differential pressure between a pressure produced by said brake fluid pressure producing device and a pressure applied to said wheel braking force generating device which is generated by said rotary type pump;
• a third conduit connecting said reservoir to said first conduit between said brake fluid pressure producing device and said differential pressure maintaining device;
• and
• a control valve disposed in said third conduit and switched between a flow-through position and a cut-off position,
• wherein said reservoir has a first reservoir port which is connected to said third conduit and through which brake fluid is interrupted to flow from said third conduit when a predetermined amount of brake fluid is accumulated in said reservoir, and a second reservoir port connected to said second conduit.

A brake apparatus for a vehicle comprising:

• a master cylinder for producing master cylinder pressure at a depressing stroke of a brake pedal in response to a braking operation of an operator;
• a wheel cylinder for receiving said master cylinder pressure and generating wheel braking force in accordance with wheel cylinder pressure applied thereto;
• a first conduit connecting said wheel cylinder to said master cylinder;
• an anti-skid control device comprising a pressure-increasing control valve and a pressure-reducing control valve for controlling slip state of a wheel;
• a linear differential pressure valve provided in said first conduit, for maintaining differential pressure between said master cylinder pressure and a pressure applied to said wheel cylinder;
• a reservoir for accumulating brake fluid which is expelled from said wheel cylinder through said pressure-reducing control valve when said brake fluid pressure applied to said wheel cylinder is reduced to eliminate a tendency for a wheel to be locked and for temporarily accumulating brake fluid which flows directly from said master cylinder;
• a rotary type pump for taking in said brake fluid accumulated in said reservoir and discharging into said first conduit, the rotary type pump producing a wheel cylinder pressure higher than a master cylinder pressure at the depressing stroke of the brake pedal;
• a control valve provided between said master cylinder and aid reservoir and switched between a flow-through position and a cut-off position;
• and
• prohibiting means for prohibiting brake fluid flowing into aid reservoir from said master cylinder when a predetermined amount of brake fluid is accumulated in said reservoir.

A brake apparatus for a vehicle, comprising:

• a master cylinder for producing master cylinder pressure at a depressing stroke of a brake pedal in response to braking operation of an operator;
• a wheel cylinder for receiving said master cylinder pressure and generating wheel braking force in accordance with wheel cylinder pressure applied thereto;
• a first conduit connecting said wheel cylinder to said master cylinder;
• an anti-skid control device having a pressure-reducing control valve disposed at said first conduit for controlling slip state of a wheel;
• a differential pressure valve provided in said first conduit between said master cylinder and said anti-skid control device and switched between a flow-through position and a differential pressure producing position at which differential pressure between said master cylinder pressure and a pressure applied to said wheel cylinder is maintained;
• a reservoir connected in fluid circuit with said anti-skid control device and said master cylinder for accumulating brake fluid which is expelled from said wheel cylinder through said pressure-reducing control valve when said brake fluid pressure applied to said wheel cylinder is reduced and for temporarily accumulating brake fluid which flows directly from said master cylinder even at the depressing stroke of brake pedal;
• and
• a rotary type pump for taking in said brake fluid accumulated in said reservoir and discharging into said first conduit between said differential pressure valve and said anti-skid control device, the rotary type pump producing a wheel cylinder pressure higher than a master cylinder pressure at the depressing stroke of the brake pedal.