Power plants – Pressure fluid source and motor – Pulsator
Patent
1995-05-04
1997-06-03
Lopez, F. Daniel
Power plants
Pressure fluid source and motor
Pulsator
60594, 60403, 92129, 180271, B60T 1320
Patent
active
056343370
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to braking assemblies made up of pneumatic boosters and master cylinders, of the type of those which are used to boost the braking of motor vehicles.
Pneumatic boosters conventionally include a casing fixed to a wall separating a passenger compartment from a front compartment of the vehicle, and divided in leaktight fashion by a movable wall structure into a front chamber permanently connected to a source of partial vacuum and a rear chamber connected selectively to the front chamber or to the atmosphere by a valve means actuated by a control rod capable of bearing, by means of the front face of a plunger, on the rear face of a reaction disk secured to a push rod.
In parallel with this, master cylinders conventionally include a body formed with at least two flanges for fixing the master cylinder onto the casing of the booster, each flange interacting with a screw and a nut, at least one piston sliding in a bore formed axially in the body of the master cylinder so that the push rod of the booster interacts with the piston of the master cylinder when the control rod of the booster is actuated.
Many documents illustrate this type of braking assembly. They are usually located in the front compartment of a motor vehicle, generally containing the engine of the vehicle, the booster being fixed via its rear wall onto the separating bulkhead between this front compartment and the passenger compartment, and the master cylinder being fixed to the front wall of the booster. The control rod of the booster passes through an opening in the bulkhead and it is actuated by a brake pedal in the passenger compartment.
In the event of a frontal or almost-frontal collision of the vehicle with another vehicle or with a stationary obstacle, the structure and bodywork of the vehicle are designed to deform progressively in order to absorb the greatest possible amount of the energy involved in this collision.
It is nevertheless often the case that the engine, or the load transported in the front compartment of the vehicle, moves back under the effect of such a collision and interferes with the master cylinder. Such an interference may result in the application to the master cylinder of a force directed along its axis, or a force forming a certain angle with its axis. The result, however, is that in all cases the master cylinder, by means of its fixing flanges, pushes the casing of the booster back towards the bulkhead of the vehicle, and by means of its piston, pushes back the push rod and therefore the control rod of the booster which is coaxial with it.
It therefore follows that the consequence of a frontal or almost-frontal collision, owing to the arrangement of the booster/master cylinder assembly in the front compartment of the vehicle, firstly causes the bulkhead to move back under the action of the casing of the booster, this being all the more intense if the booster is equipped with tie rods, and also causes the brake pedal to move back, this moving further if the booster/master cylinder assembly was being actuated at the moment of the collision, that is to say if a high pressure was prevailing inside the master cylinder, these two effects adding together and being capable of giving rise to substantial injuries to the driver of the vehicle.
Various documents have already attempted to provide a solution to this problem. The document FR-A2,437,337, for example, makes provision for the sector of bulkhead placed above the space where the driver places his feet to be situated as close as possible to the steering, and for the front sector of bulkhead to extend forward as far as a stationary articulation point provided in the front compartment, to which point is fixed a support intended to receive a braking assembly as defined above, this support being shaped and arranged so that it can pivot about this stationary articulation point under the effect of a substantial thrust.
The document FR-A-2,482,547 for its part makes provision for fixing the booster to the upper element of an impact-absorbing struct
REFERENCES:
patent: 2395223 (1946-02-01), Ingres
patent: 3065603 (1962-11-01), Randol
patent: 4354353 (1982-10-01), Laue
patent: 4506592 (1985-03-01), Shimamura
patent: 4785628 (1988-11-01), Myers
patent: 4815293 (1989-03-01), Cadeddu
Cobianchi Flavio
Gautier Jean Pierre
Perez Revilla Miguel
Verbo Ulysse
AlliedSignal Europe Services Techniques
Lopez F. Daniel
McCormick Jr. Leo H.
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