Fluid-pressure and analogous brake systems – Multiple fluid-receiving devices – Multiple motors
Reexamination Certificate
2000-05-22
2002-05-21
Schwartz, Christopher P. (Department: 3613)
Fluid-pressure and analogous brake systems
Multiple fluid-receiving devices
Multiple motors
C303S009720, C303S115500, C188S345000
Reexamination Certificate
active
06390566
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle braking device.
In addition, the present invention relates to an improved vehicle braking system wherein output ports of a master cylinder operated by an operator are connected to one of a front wheel brake and a rear wheel brake and to a pressure intensification mechanism for generating a hydraulic pressure intensified in response to a hydraulic pressure outputted from the output port of the master cylinder, whereby the other of the front wheel brake and the rear wheel brake is operated by virtue of the hydraulic pressure generated from the pressure intensification mechanism.
Further, the present invention also relates a braking system for automotive two-wheeled vehicles, and in particular to a braking system for automotive two-wheeled vehicles in which a primary wheel cylinder and a secondary wheel cylinder are provided on a wheel brake means for braking a wheel which are adapted to cause the wheel the brake means to operate when supplied with hydraulic pressure, respectively.
The vehicle braking system is disclosed, for example, in a Japanese Patent Unexamined Publication No. Hei. 5-50972 and is already known.
In the vehicle braking system disclosed therein, the pressure intensification mechanism is constituted by a secondary master cylinder operated by a reaction torque when a front wheel brake is operated by a hydraulic pressure outputted from a front wheel master cylinder.
Therefore, functionally, the secondary master cylinder has to be disposed in the vicinity of the wheel and this increases the unsprung load (that is, non-suspended mass) of the vehicle, slightly deteriorating the riding comfort of the vehicle.
In addition, the other braking system for automotive two-wheeled vehicles, is known by for example, Japanese Patent Examined Publication No. Sho. 62-25550. The braking system is constituted in such a manner that first and second disc brakes are disposed on sides of a front wheel, in which an output port of a primary master cylinder for generating a hydraulic pressure when operated by an operator connects to a wheel cylinder of the first disc brake, in which a secondary master cylinder is mounted on a front fork which is adapted to be caused to operate by virtue of a rotational torque which the secondary master cylinder receives from the front wheel in conjunction with the operation of the first disc brake, and in which an output port of this secondary master cylinder connects to a wheel cylinder of a second disc brake. According to this conventional braking system, when the first disc brake is in operation by virtue of a hydraulic pressure outputted from the primary master cylinder, the secondary master cylinder is caused to operate by making use of the rotational torque of the front wheel, and the second disc brake is then caused to operate by virtue of a hydraulic pressure outputted from the secondary master cylinder. Therefore, a great magnitude of braking force can be provided even by applying a relatively small magnitude of operating force to the primary master cylinder, whereby a nimble braking operation can be performed.
In the conventional braking system as described above, since the secondary master cylinder adapted to operate by virtue of the rotational torque of the wheel has to be disposed in the vicinity of the wheel from the functional point of view, the secondary master cylinder increases the unsprung load of an automotive two-wheeled vehicle, and this somehow functions to deteriorate the riding comfort of the vehicle.
SUMMARY OF THE INVENTION
The present invention was made in view of the above situations.
It is an object of the present invention to provide an improved vehicle braking system in which a sufficient magnitude of braking force can be provided without increasing the unsprung load of the vehicle.
In addition, it is an object of a first aspect of the present invention to provide a vehicle braking system comprising a proportional pressure intensification valve for generating a boosting hydraulic pressure intensified in proportion to a hydraulic pressure outputted from a master cylinder without increasing the unsprung load of the vehicle.
The object can be achieved by a vehicle braking system, according to the present invention, comprising:
a front wheel brake;
a rear wheel brake;
a master cylinder adapted to be operated by an operator, the master cylinder having output ports of the master cylinder which are connected to one of the front wheel brake and the rear wheel brake;
a hydraulic pressure source; and
a proportional pressure intensification valve for drawing a boosting hydraulic pressure in proportion to a hydraulic pressure outputted from the master cylinder from the hydraulic pressure source into a hydraulic pressure boosting chamber thereof,
wherein the hydraulic pressure boosting chamber of the proportional pressure intensification valve is connected to the other of the front wheel brake and the rear wheel brake.
In addition, the object can be achieved by a braking system for automotive two-wheeled vehicle, according to the present invention, comprising:
a wheel brake mechanism for braking a wheel, the wheel brake mechanism having a primary wheel cylinder and a secondary wheel cylinder and are adapted to cause the wheel brake mechanism operate when the primary and secondary wheel cylinders are supplied with hydraulic pressure, respectively;
a master cylinder adapted to be operated by an operator, the master cylinder having an output port which connects to the primary wheel cylinder;
a hydraulic pressure source including a hydraulic pump; and
a proportional pressure intensification valve for drawing a boosting hydraulic pressure in proportion to a hydraulic pressure outputted from the master cylinder from the hydraulic pressure source into a hydraulic pressure boosting chamber thereof, the hydraulic pressure boosting chamber being connected to the secondary wheel cylinder.
Further, it is also an object of a second aspect of the present invention to provide a braking system for automotive two-wheeled vehicle which is constructed so as to braking a wheel of the vehicle in a nimble fashion without increasing the unsprung load thereof.
The aforesaid object, in particularly the aforesaid object of the first aspect of the present invention can be attained by the first to eight feature explained below according to the present invention.
According to a first feature of the invention, there is provided a vehicle braking system comprising a master cylinder adapted to be operated by an operator, a source of hydraulic pressure and proportional pressure intensification valves for each drawing a boosting hydraulic pressure in proportion to a hydraulic pressure outputted from the master cylinder from the source of hydraulic pressure into a hydraulic pressure boosting chamber thereof, wherein output ports of the master cylinder are connected to one of pairs of front wheels and rear wheels and wherein the output chambers of the proportional pressure intensification valves are connected to the other pair of the pairs of front wheels and rear wheels.
According to this first feature of the invention, the hydraulic pressure outputted from the master cylinder is supplied to one of the pairs of front wheel brakes and rear wheel brakes for operating the same when the master cylinder is in operation. In addition, the proportional pressure intensification valves draw the boosting hydraulic pressure intensified in proportion to the hydraulic pressure outputted from the master cylinder from the source of hydraulic pressure into the hydraulic pressure boosting chambers thereof for supplying the boosting hydraulic pressure to the other of the pairs of front wheel brakes and rear wheel brakes for operating the same.
Thus, since the proportional pressure intensification valves are adapted to draw the boosting hydraulic pressures intensified in proportion to the hydraulic pressure outputted from the master cylinder from the source of hydraulic pressure for supplying it to the other wheel brake
King Bradley
McGuireWoods LLP
Nissin Kogyo Co. Ltd.
Schwartz Christopher P.
LandOfFree
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