Fluid-pressure and analogous brake systems – Multiple systems – Fluid pressure and electric
Reexamination Certificate
2000-01-28
2001-08-28
Butler, Douglas C. (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple systems
Fluid pressure and electric
C188S358000, C303S114100, C303S114200, C303S002000, C303S113400, C303S010000, C303S166000
Reexamination Certificate
active
06280002
ABSTRACT:
This invention relates to a hydraulic braking system for a vehicle wherein operational pressurized fluid is supplied to a remote actuator assembly to operate a master cylinder that pressurizes fluid that is supplied to wheel brakes to effect a brake application. An operator applies an input force to a force sensor, which supplies an electronic control unit with an input signal indicating a desired braking for the vehicle. The electronic control unit develops an operational signal as a function of the input signal, deceleration of the vehicle and the flow of the pressurized fluid of a source. The operational signal is supplied from the electronic control unit to a magnetic responsive valve as a pulse modulated operational signal such the flow of pressurized fluid from the source to a steering gear is restricted to correspondingly increase in the fluid pressure therein to an operational pressure to activate the remote actuation assembly.
BACKGROUND OF THE INVENTION
Hydraulic brake boosters have been designed to provide an assist in the actuation of a master cylinder to pressurize fluid to developed a force to effect a brake application. In order to reduce the cost of a hydraulic brake booster, often the same hydraulic power source used to supply a steering gear is used to power a hydraulic brake booster. The controls for such hydraulic brake boosters are designed such that a minimum amount of hydraulic fluid is always available for operation of either the hydraulic brake booster or the steering gear. In certain brake boosters, of a type disclosed in U.S. Pat. Nos. 3,967,536; 4,131,055; 4,179,980; 4,514,981; 4,724,674 and 5,442,916, the booster operates by restricting flow from one side of a power piston to the other side of the power piston to create a fluid pressure differential which causes the power piston to move and provide power assisted displacement of the pistons in a master cylinder. In this type of brake booster, the master cylinder and booster are joined together and as a result the overall length occupies considerable under hood space of a vehicle. Because of the efficiency of such brake boosters they have found application in many vehicles and in particular van and certain mid-sized trucks. However, in some models of recently manufactured vehicle, the physical design of the under hood space is often restricted or reduced, and as a consequently locating a brake booster and other components is often a difficult task. To better utilize under hood space, it has been disclosed in U S. Pat. Nos. 5,329,769, 5,313,796 and U.S. patent application Ser. No. 09/097,778, now U.S. Pat. No. 6,038,857 that certain brake systems components could be located remotely from under the hood. These brake systems functioning in an adequate manner but require a considerable number of components in the control apparatus to provide a stable and smooth application of the wheel brakes.
U.S. Pat. No. 4,865,399 discloses an anti-lock brake system wherein pressurized fluid developed by a pump system is supplied to wheel brakes to effect a brake application. The time the pressurized fluid is supplied to any individual wheel brake is alternately increased and decreased through the actuation of a solenoid valve by a pulse-width-modulated signal to produce a desired braking deceleration for a vehicle.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide a hydraulic brake system wherein pressurized fluid is supplied to wheel brakes to effect a brake application in response to braking signals generated through an electronic control unit (ecu) which supplies a magnetic responsive valve with a pulse modulated operational signal to create a variable orifice. The creation of the variable orifice in the magnetic responsive valve restricts the flow of pressurized fluid from a source to a steering gear and increases the fluid pressure of the fluid therein from a source, a portion of the fluid with the increased fluid pressure is thereafter supplied to activate an actuator assembly and operate a master cylinder that produces pressurize fluid that is supplied to wheel brakes to effect a desired brake application.
In more particular detail, in the present invention of a hydraulic brake system for the vehicle, a portion of a volume of a first fluid from a first source supplied to a steering system is selectively diverted to an actuator assembly for a master cylinder as a function of the a braking operational signal developed by an ecu including a pulse width modulation signal for operating a magnetic responsive valve in the fluid circuit of the steering system. The ecu for the hydraulic brake system develops the operational braking signal from various inputs including a first input signal indicative of the flow of the first fluid in the steering circuit, a second input signal indicative of an input force applied by the operator to a brake pedal and a third input signal indicative of the movement of the wheels of the vehicle. The ecu supplies the pulse modulated operational signal to the magnetic responsive valve to restrict the flow of the first fluid to the steering by creating a variable orifice in the magnetic responsive valve. Restriction of the flow of the first fluid to the steering circuit causes an increase in the fluid pressure of the first fluid. This increase in the fluid pressure of the first fluid is communicated to the actuator assembly to develop an operational force in a second fluid that is supplied to wheel brakes to effect a brake application in response to an operator input force applied to a input member. The ecu continues to supplies a pulse modulated operational signal to the magnetic responsive valve until a desired rate of braking occurs in the vehicle corresponding to the operator input as indicated by the second input signal. In the absence of the first signal, the ecu supplies a back-up pump with an actuation signal which supplies the actuator assembly with a secondary pressurized fluid to create an operational force to effect a brake application. In the absence of the first signal and actuation of the back-up pump, the input assembly acts through a reaction assembly to pressurized fluid which is supplied to the wheel brakes to effect a brake application.
An advantage of this hydraulic brake system of this invention resides in the actuation of a magnetic responsive valve by a pulse modulated operational signal developed by an ecu as a function of an input force from an operator, motion or movement of a vehicle and fluid pressure developed by the restriction of flow through a variable orifice to produce an actuation force.
A further advantage of this brake system of this invention is by providing by a hydraulic brake system with a primarily braking circuit through the activation of a pulse modulated magnetic responsive valve to create a first operational force for a master as a function of an operator input force, movement of the vehicle, and the availability of fluid pressure from a first source, secondarily braking circuit through the activated by an electric pump to create a second operational force as a function of an operator input force, movement of the vehicle and fluid pressure developed in a fluid by the electric pump and a manual or back up circuit through wherein fluid pressure is developed by the operator input moving a piston in a reaction assembly to provide pressurized fluid to effect a brake application.
REFERENCES:
patent: 3810680 (1974-05-01), Schenk
patent: 3967536 (1976-07-01), Bach
patent: 3981543 (1976-09-01), Atkins
patent: 4175794 (1979-11-01), Pauwels
patent: 4182536 (1980-01-01), Pauwels
patent: 4492414 (1985-01-01), Kozakai et al.
patent: 4779422 (1988-10-01), Brown
patent: 5310251 (1994-05-01), Towers et al.
patent: 5531509 (1996-07-01), Kellner et al.
patent: 5549361 (1996-08-01), Sorensen
patent: 5983637 (1999-11-01), Lubbers et al.
patent: 6007160 (1999-12-01), Lubbers et al.
patent: 6038857 (2000-03-01), Towers et al.
patent: 6142584 (2000-11-01), Towers et al.
patent: 6149248 (2000-11-01), Lubbers et al.
Albert Timothy Jay
Goodzey Gregory Paul
Heinz Bryan Frances
Butler Douglas C.
Comstock Warren
McCormick Jr. Leo H.
Robert Bosch Corporation
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