Power plants – Pressure fluid source and motor – Pulsator
Patent
1993-07-23
1995-08-22
Lopez, F. Daniel
Power plants
Pressure fluid source and motor
Pulsator
913692, B60T 1320
Patent
active
054429170
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a force transmission device for an assembly consisting of a pneumatic brake-booster and of a master cylinder, comprising: movement in an axial direction under the effect of an input force, this rod being terminated by a plunger; position, under the effect of a pressure differential controlled by the axial movement of the control rod, this pneumatic piston having an axial annular surface which surrounds the plunger; onto which the axial annular surface of said pneumatic piston and the plunger are capable of applying output forces; forces and another end of which retransmits them to a hydraulic piston of the master cylinder; and axial direction.
Such a device is for example described in U.S. Pat. No. 4,984,506 and well known in the prior art.
In a general way, brake-boosters and the master cylinders which are associated therewith are mass-produced and are for this reason subject to very delicate compromises as far as the cost and the precision of production are concerned.
This leads in particular to major difficulties in obtaining a perfect alignment of the thrust rod with the control rod, without which deformations under stress, followed by irreversible damage to the booster may appear.
The object of the present invention is to provide simple and economical means for avoiding the detrimental consequences of such a lack of perfect alignment.
To this end, the device of the invention is essentially characterized in that the thrust rod is securely attached, at its first end, to a flat thrust washer coming to bear, with the possibility of a relative sliding, against the flat bottom of said cup, and in that said retaining means are borne by the master cylinder.
In the case where the hydraulic piston of the master cylinder has an axial cylindrical bore into which the second end of the thrust rod enters, said retaining means preferably comprise a restriction of the internal diameter of this bore, adapted to limit the possibility of the thrust rod deviating from said axial direction.
The invention will now be described by way of example with reference to the accompanying single FIGURE which is a view in partial cross section of a device according to the invention.
Insofar as the invention relates only to an improvement made to pneumatic brake-booster systems, and insofar as the general constitution and operation of these systems are well known to the person skilled in the art, these systems will be rapidly recalled here only in order to provide a total understanding of the improvement which the invention represents.
In a simplified manner, a system of this type comprises a booster 1 and a master cylinder 2.
The booster per se comprises a rigid casing 3 separated into two chambers 3a and 3b, in leaktight manner, by a membrane 4 securely attached to a pneumatic piston 5 movable inside the casing.
The front chamber 3a, the front face of which is closed in leaktight manner by the master cylinder 2, is permanently connected to a partial vacuum source (not shown) through a union 6.
The pressure in the back chamber 3b is controlled by a valve 7, controlled by a control rod 8, which is connected to the brake pedal.
When the control rod 8 is in resting position, in this case pulled toward the right, the valve 7 establishes a communication between the two chambers 3a and 3b of the booster.
The back chamber 3b then being subject to the same partial vacuum as the front chamber 3a, the piston 5 is pushed back toward the right, in resting position, by a spring 9.
The actuation of the control rod 8 toward the left has the effect, in a first stage, of moving the valve 7 so that it isolates one of the chambers 3a and 3b from the other and then, in a second stage, of moving this valve so that it opens the back chamber 3b to atmospheric pressure.
The pressure differential between the two chambers then sensed by the membrane 4 exerts on the piston 5 a thrust which tends to move it toward the left compressing the spring 9.
The braking force which the control rod 8 exerts, through the intermediary of a pl
REFERENCES:
patent: 3040535 (1962-06-01), Randol
patent: 3094844 (1963-06-01), Helvern
patent: 4453380 (1984-06-01), Meynier
patent: 4506592 (1985-03-01), Shimamura
patent: 4856412 (1989-08-01), Kawasumi et al.
patent: 4984506 (1991-01-01), Perez
Gautier Jean Pierre
Revilla Perez
Verbo Ulysse
Bendix Europe Services Techniques
Lopez F. Daniel
McCormick Jr. Leo H.
Palguta Larry J.
LandOfFree
Force transmission device with flat support does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Force transmission device with flat support, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Force transmission device with flat support will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2134407