Fluid-pressure and analogous brake systems – Speed-controlled – With failure responsive means
Reexamination Certificate
1998-09-09
2001-07-03
Oberleitner, Robert J. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
With failure responsive means
C303S116200, C303S009000, C303S191000
Reexamination Certificate
active
06254202
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle braking apparatus capable of operating a brake cylinder with a hydraulic braking pressure produced by a master cylinder connected to a vacuum booster and a hydraulic braking pressure produced by a hydraulic pressure pump.
2. Description of the Related Art
A vehicle which travels while automatically maintaining a predetermined intervehicular distance from a preceding vehicle requires an automatic braking apparatus for decelerating the vehicle when the intervehicular distance is short. As such an automatic braking apparatus, it is known that there is an apparatus which causes a master cylinder to produce a predetermined hydraulic braking pressure and operates a brake cylinder by controlling a vacuum booster associated with the master cylinder by means of a linear solenoid.
However, the hydraulic braking pressure which can be produced by the vacuum booster and the master cylinder is not always sufficiently high, and there is a possibility that the required braking force may not be obtained in case of emergency such as panic braking. It is also necessary to provide some kind of backup function to prepare for the occurrence of a failure in the vacuum booster or the master cylinder.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-described limitation of the known apparatus, and its object is to add an emergency backup function to a braking apparatus which produces a hydraulic braking pressure by means of a vacuum booster and a master cylinder.
To achieve the above object, a first feature of the present invention is the provision of a vehicle braking apparatus capable of operating a brake cylinder with a hydraulic braking pressure produced by a master cylinder connected to a vacuum booster and a hydraulic braking pressure produced by a hydraulic pressure pump, comprising: normal mode braking means for operating the brake cylinder with the hydraulic braking pressure produced by the master cylinder; and emergency mode braking means for operating the brake cylinder with the hydraulic braking pressure increased by the hydraulic pressure pump when an insufficient braking force is obtained from the hydraulic braking pressure produced by the master cylinder.
According to the above construction, it is possible to minutely control the braking force by performing braking with the normal mode braking means using the hydraulic braking pressure produced by the master cylinder during normal braking. In case of emergency in which an insufficient braking force is obtained from the hydraulic braking pressure produced by the master cylinder, the required braking force can be ensured by performing braking with the hydraulic braking pressure produced by the hydraulic pressure pump.
A second feature of the present invention, in addition to the first feature, is a vehicle braking apparatus wherein the emergency mode braking means operates the brake cylinder when a target deceleration is at least a predetermined value.
According to the above construction, even if a large target deceleration is required to be achieved by the emergency mode braking means, and such target deceleration cannot be achieved by the normal mode braking means with the hydraulic braking pressure produced by the master cylinder, it is possible to achieve the target deceleration by performing braking with the emergency mode braking means using the hydraulic braking pressure produced by the hydraulic pressure pump. Although the predetermined value is set to be 0.6G in a given embodiment, such a value is a matter of design variation which can be arbitrarily determined.
A third feature, in addition to the first feature, is a vehicle braking apparatus wherein the emergency mode braking means operates the brake cylinder when a braking system associated with the vacuum booster and the master cylinder fails.
According to the above construction, even if the braking system associated with the vacuum booster and the master cylinder fails, it is possible to perform braking with the hydraulic braking pressure produced by the hydraulic pressure pump.
A fourth feature, in addition to the first feature, is a vehicle braking apparatus wherein the hydraulic pressure pump is also used for at least one of an anti-lock braking system and a brake traction control system.
According to the above construction, during the emergency in which the required braking force is not obtained from the hydraulic braking pressure produced by the master cylinder, appropriate braking is performed by using the hydraulic pressure pump of the anti-lock braking system or the brake traction control system. Accordingly, since it is unnecessary to use a special hydraulic pressure pump, a reduction in cost can be realized.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment, with reference to the accompanying drawings.
REFERENCES:
patent: 5278764 (1994-01-01), Iizuka et al.
patent: 5709438 (1998-01-01), Isakson et al.
patent: 5947566 (1999-09-01), Tobisawa et al.
Blackman William D.
Carrier Joseph P.
Carrier Blackman & Associates P.C.
Honda Giken Kogyo Kabushiki Kaisha
Kramer Devon
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