Fluid-pressure and analogous brake systems – Multiple systems – Fluid pressure and electric
Reexamination Certificate
1999-03-10
2001-04-17
Schwartz, Christopher P. (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple systems
Fluid pressure and electric
Reexamination Certificate
active
06217127
ABSTRACT:
This application is based on and claims priority under 35 U.S.C. § 119 with respect to Japanese Application No. 10(1998)-57880 filed on Mar. 10, 1998 and Japanese Application No. 10(1998)-268821 filed on Sep. 24, 1998, the entire content of both of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention generally relates to a vehicle brake system. More particularly, the present invention pertains to a master cylinder device and a hydraulic brake device for a vehicle which are provided with a pedal stroke simulator.
BACKGROUND OF THE INVENTION
Japanese Patent Application Laid-Open Publications Nos. 57(1982)-84249, 58(1983)-39551 and 5(1993)-319245 disclose hydraulic braking devices that include a power hydraulic pressure source and a master cylinder which is operatively connected to a brake pedal. In this hydraulics brake device, the hydraulic pressure having a magnitude corresponding to the depressed force of the brake pedal is applied from the power hydraulic pressure source to the wheel brakes when the power hydraulic pressure source is in the normal condition, and the hydraulic pressure in applied from the master cylinder to the wheel brakes when the power hydraulic pressure source is in the abnormal condition. This hydraulic brake device further includes a pedal stroke simulator for generating a stroke of the brake pedal corresponding to the depressed force applied to the brake pedal when the power hydraulic pressure source is in the normal condition.
In the devices described above, however, the brake pedal does not move unless the piston of the pedal stroke simulator and the pistons of the master cylinder begin to slide, and the load or force required to make the pistons of the pedal stroke simulator and the master cylinder begin to slide is relatively high. As a results an operational feeling of the brake pedal deteriorates.
In light of the foregoing, a need exists for a master cylinder and hydraulic braking device that are not as susceptible to the same disadvantages and drawbacks as described above.
It would be desirable to provide a master cylinder and hydraulic braking device in which the operational feeling of the brake pedal is not diminished.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, a master cylinder device includes a pedal stroke simulator having a piston connected to a brake pedal for generating, upon stroke of the brake pedal, a stroke corresponding to the operating force applied to the brake pedal, and a master cylinder operated by the operation of the brake pedal through the piston of the pedal. A load transmitting elastic member is interposed between the piston of the pedal stroke simulator and the brake pedal. The load transmitting elastic member has a set load that is lower than a predetermined load required for causing the piston to begin sliding movement and having a maximum load that is higher than the predetermined load.
According to another aspect of the present invention, a master cylinder device includes a master cylinder having a piston connected to a brake pedal, and a pedal stroke simulator for generating, upon stroke of the brake pedal, a stroke corresponding to the operating force applied to the brake pedal. A load transmitting elastic member is interposed between the piston of the master cylinder and the brake pedal, with the load transmitting elastic member possessing a set load that is lower than a predetermined load required to begin sliding movement of the piston and having a maximum load that is higher than the predetermined load.
According to an additional aspect of the present invention, a vehicle hydraulic brake device includes a pedal stroke simulator having a piston connected to a brake pedal for generating, upon operation of the brake pedal, a stroke corresponding to the operating force applied to the brake pedal, a master cylinder operated by the operation of the brake pedal through the piston of the pedal stroke simulator, a power hydraulic pressure source for generating hydraulic pressure, a wheel brake mounted on a wheel of the vehicle for braking the wheel, and control means for applying hydraulic pressure from the power hydraulic pressure source to the wheel brake in response to the operation of the brake pedal when the power hydraulic pressure source is in the normal condition and for applying hydraulic pressure from the master cylinder to the wheel brake when the power hydraulic pressure source is in the abnormal condition. A load transmitting elastic member is interposed between the piston of the pedal stroke simulator and the brake pedal. The load transmitting elastic member has a set load that is lower than the predetermined load required for causing the piston to begin sliding and has a maximum load that is higher than the predetermined load.
According to a further aspect of the invention, a hydraulic brake device for a vehicle includes a master cylinder having a piston connected to a brake pedal, a pedal stroke simulator for generating, upon brake pedal stroke, a stroke corresponding to the operating force applied to the brake pedal, a power hydraulic pressure source for generating hydraulic pressure, and a wheel brake mounted on the wheel of the vehicle for braking the wheel. A hydraulic pressure control device applies the hydraulic pressure from the power hydraulic pressure source to the wheel brake in response to the operation of the brake pedal when the power hydraulic pressure source is in the normal condition and applies the hydraulic pressure from the master cylinder to the wheel brake when the power hydraulic pressure source is in the abnormal condition. A load transmitting elastic member is interposed between the piston of the master cylinder and the brake pedal, and has a set load that is lower than a predetermined load required for making the piston begin to slide and a maximum load that is higher than the predetermined load.
REFERENCES:
patent: 5421643 (1995-06-01), Kirchner
patent: 5531509 (1996-07-01), Kellner
patent: 5567021 (1996-10-01), Gaillard
patent: 57-84249 (1982-05-01), None
patent: 58-39551 (1983-03-01), None
patent: 5-319245 (1993-12-01), None
patent: 10-167042 (1998-06-01), None
Aizawa Hiroaki
Kusano Akihito
Toda Hiroshi
Aisin Seiki Kabushiki Kaisha
Bartz C. T.
Burns Doane , Swecker, Mathis LLP
Schwartz Christopher P.
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