Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1988-02-11
1989-05-30
Butler, Douglas C.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
303 68, 303 92, 303110, 303116, B60T 846, B60T 888, B60T 1368
Patent
active
048344699
DESCRIPTION:
BRIEF SUMMARY
FIELD OF TECHNOLOGY
The present invention relates to a failsafe, highly reliable brake pressure control system for use with a vehicle having two brake piping lines and which provides various types of brake force control including boost control of braking force, control of distribution of braking force, antilock control, traction control for the wheels, and automatic braking for maintaining the stopped state, adjusting the distance between the cars, and avoiding obstacles on the road.
TECHNOLOGICAL BACKGROUND
The abovementioned various types of controls of braking force have heretofore been dealt individually by means of separate control units or separate systems each including an electronic control unit. However, such controls are possible by combining the increase, decrease and retaining of the brake fluid pressure both in braking and non-braking conditions. If one individual unit or system is allocated to each control factor, similar control elements have to be used for different controls, thus incurring such problems as economical loss, poor reliability, reduction in the space available in the vehicle and increase in the overall weight of the vehicle. An integrated system which can comprehensively deal all the controls would be very desirable.
In U.S. Pat. No. 3,667,813, there is disclosed a system which solves the abovesaid problem in the simplest way. In this system, a shut-off valve is provided in a piping line connecting a master cylinder with a wheel brake so as to open and close the brake fluid feed line. Also, between the shut-off valve and the brake are provided an access valve which electromagnetically changes over to selectively introduce or hold the pump pressure produced by a pump provided separately from the master cylinder and an electromagnetic discharge valve for selectively discharging or holding the fluid pressure so as to apply a pump pressure to the brakes and achieve a desired braking force. Besides, many similar systems are known in which an electromagnetic discharge valve is provided directly in a brake piping line. Also known are systems adapted to control the brake force indirectly by controlling the pressure in a control system.
In contrast, in a system in which a discharge valve is directly connected to a brake line, the malfunction of the discharge valve owing to worn sealing surfaces or foreign matters mixed in the brake fluid will directly lead to the loss of pressure on the brakes, thus bringing about a grave danger.
Many of the systems having a control line separate from the brake line are provided with various failsafe mechanisms so that the brake line will supply brake pressure even in case of the failure of a discharge valve disposed in the control line. But these systems have their drawbacks in that they structurally consume more brake fluid for the brake line and that the maximum attainable brake pressure is insufficient.
An object of the present invention is to solve the grave and critical problems of the prior art.
DISCLOSURE OF INVENTION
In order to achieve this object, the present invention provides a brake pressure control system including a discharge valve provided in a discharge line for control fluid fed from a control chamber and having an on-off valve means for opening and closing the discharge line, the opening lowering the control fluid pressure in the control chamber to reduce the braking force directly or indirectly, characterized in that two or more valve means of the discharge valves are provided in series in the discharge line.
Thus, even if any one of the valves should lose its sealing function for some reason, the remaining normal valve will prevent the leakage of the control fluid from the control chamber, thus avoiding the abovesaid problems.
The system of the present invention provides an economical arrangement and yet improves the safety of the vehicle equipped with the system. The safety of the system is further improved by designing the second valve to stop it from opening by utilizing an increase in the valve-closing force by the flui
REFERENCES:
patent: 3667813 (1972-06-01), Burckhardt et al.
patent: 3697138 (1972-10-01), Marting
patent: 3771839 (1973-11-01), Fink
patent: 3975061 (1976-08-01), Kondo et al.
patent: 4215902 (1980-08-01), Sato et al.
patent: 4416347 (1983-11-01), Bertling et al.
patent: 4482192 (1984-11-01), Leiber
patent: 4561701 (1985-12-01), Fujii et al.
Hashida Koichi
Kohno Teruhisa
Butler Douglas C.
Sumitomo Electric Industries Ltd.
LandOfFree
Brake pressure control system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Brake pressure control system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brake pressure control system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2147662