초록 ▼

A vehicle brake booster and master cylinder assembly has a vacuum suspended booster section which is controlled by movement of the vehicle brake pedal. A hydraulic booster section is in series with the vacuum suspended booster section, and a master cylinder unit is in series with the hydraulic boost

A vehicle brake booster and master cylinder assembly has a vacuum suspended booster section which is controlled by movement of the vehicle brake pedal. A hydraulic booster section is in series with the vacuum suspended booster section, and a master cylinder unit is in series with the hydraulic booster section. The assembly is so arranged that in normal operation the vehicle operator obtains booster brake actuating pressures by operation of the vacuum suspended booster which acts through the hydraulic booster mechanism without operating the hydraulic booster. When greater brake actuating pressures are required, as indicated by increased brake pedal force exerted by the operator, the vacuum booster reaches its limit or run-out condition and the hydraulic booster is operated so as to continue the increase in master cylinder output pressure. If still further master cylinder output pressure is required when the hydraulic booster has reached its run-out condition, the master cylinder is actuated manually through mechanical force transmitting elements which are parts of the booster sections. The vacuum suspended booster section is connected to the vehicle engine intake manifold as a vacuum source, and the hydraulic booster section is connected in the hydraulic power steering gear system so that hydraulic pressure for its operation is generated by the power steering gear pump. The assembly is so interconnected that the master cylinder can be operated manually when there is no or insufficient power pressure to operate either booster section. It may also be operated by actuating the vacuum suspended booster section, and, when no hydraulic pressure is available to the hydraulic booster section, this operation may be followed by manual actuation. It may be operated by initially actuating the hydraulic booster section when there is no vacuum available for initially operating the vacuum suspended booster section, followed by manual actuation as needed. In one embodiment the assembly utilizes a single hydraulic fluid for the hydraulic booster section and for the master cylinder and brake apply circuitry. In another embodiment the hydraulic booster section is operated by a separate fluid circuit which is fluidly independent of the master cylinder and brake apply pressure circuitry.

대표청구항 ▼

A brake booster and master cylinder assembly comprising: a differential air pressure operated first booster section having first and second output members movable as a unit under power and relatively movable under manual operation; a hydraulic pressure operated second booster section in alignment wi

A brake booster and master cylinder assembly comprising: a differential air pressure operated first booster section having first and second output members movable as a unit under power and relatively movable under manual operation; a hydraulic pressure operated second booster section in alignment with said first booster section and having a power piston and open center valve control means including a first valve element on said piston and a second valve element cooperable with said first valve element to restrict hydraulic flow therebetween upon movement of said second valve element toward said piston and said first valve element to actuate said second booster section; said first booster section first output member operatively engaging said second booster section power piston in force transmitting relation to move said power piston and therefore said first valve element commensurately therewith, said first booster section second output member being operatively connected with said second valve element in force transmitting relation to move said second valve element commensurately therewith; and master cylinder brake actuating pressure generating means actuated by movement of said power piston; said first and second valve elements moving as a unit so long as said first booster section first and second output members move as a unit so that said second booster section is not power actuated, said second valve element moving toward said first valve element when said first booster section second output member moves relative to said first booster section first output member to power actuate said second booster section, said second valve element operatively engaging said second booster section power piston upon sufficient movement relative to said first valve element to provide a mechanical force transmitting path through said second booster section for manual operation of said master cylinder brake actuating pressure generating means; said assembly being operable to generate brake actuating pressure by sequential first booster section power operation and second booster section power operation and manual operation, and by any of said operations.