Motors: expansible chamber type – Working member position feedback to motive fluid control – Plural input signal means for single motor valve
Reexamination Certificate
1999-10-22
2001-06-26
Look, Edward K. (Department: 3745)
Motors: expansible chamber type
Working member position feedback to motive fluid control
Plural input signal means for single motor valve
C091S37600A
Reexamination Certificate
active
06250200
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a brake booster, and more particularly, to a brake booster with a function of an automatic brake.
DESCRIPTION OF THE PRIOR ART
A brake booster which is also capable of functioning as an automatic brake is known in the art, and comprises a valve body slidably disposed within a shell, a power piston mounted on the valve body, a constant and a variable pressure chamber defined across the power piston, a valve mechanism mounted on the valve body for controlling a switching of a flow path, and a solenoid disposed in the valve body for operating the valve mechanism, wherein the valve mechanism comprises a vacuum valve seat formed on the valve body, a tubular member disposed to be movable in the valve body, an atmosphere valve seat formed on the tubular seat, a valve element adapted to be seated on the vacuum and the atmosphere valve seat, and a valve plunger disposed to be movable relative to the valve body and the tubular member and driven forward together with the tubular member as an input shaft is driven forward, and wherein the solenoid comprises a housing mounted on the inner periphery of the valve body, a spool contained in the housing and around which a coil is disposed, and a piston disposed to be moveable along the inner periphery of the housing for interlocked movement with the tubular member, the arrangement being such that as the solenoid is energized, the piston and its interlocked tubular member are caused to move forward relative to the valve body and the valve plunger to operate the valve mechanism.
In the conventional brake booster mentioned above, as the solenoid is energized, both the piston and the tubular member are caused to move forward relative to the valve body and the valve plunger, whereby the atmosphere valve seat formed on the tubular member is removed from the valve element, allowing the brake booster to be actuated as an automatic brake without depressing a brake pedal.
It will be noticed that in the conventional arrangement, it is necessary that the piston and the tubular member be allowed to move back and forth smoothly when the brake booster is to be actuated as an automatic brake. Accordingly, there has been need in the conventional brake booster as mentioned above to allow a more smooth movement of the piston and the tubular member.
SUMMARY OF THE INVENTION
In view of the foregoing, in a brake booster as mentioned above, in accordance with the invention, a tubular guide is formed on a front portion of the piston while an annular guide is formed on a rear portion of the piston in a manner such that both the tubular guide and the annular guide are slidably fitted into the inner periphery of the housing for guiding a movement of the piston within the housing, while an outer periphery of the valve plunger toward its front end is slidably fitted into the inner periphery of the housing and an outer periphery of the valve plunger toward its axial center is slidably fitted into the inner periphery of the housing for guiding a back-and-forth movement of the valve plunger within the housing.
With the described arrangement, the piston is allowed to move back and forth smoothly within the housing as it is guided by both the tubular and annular guide while the valve plunger is allowed to move back and forth smoothly as a result of the guiding action provided by the inner periphery of the housing for the outer periphery of the valve plunger toward the front end and toward the axial center thereof. This assures a more smooth movement of the piston and the valve plunger as compared with the prior art.
REFERENCES:
patent: 6155156 (2000-12-01), Takasaki et al.
patent: 9-2243 (1997-01-01), None
Ikeda Masahiro
Saito Naohito
Takasaki Yoshiyasu
Bosch Braking Systems Co. Ltd.
Flynn ,Thiel, Boutell & Tanis, P.C.
Leslie Michael
Look Edward K.
LandOfFree
Brake booster 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 booster, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brake booster will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2509877