Control assembly for a hydraulic circuit of a vehicle

The control assembly for a hydraulic circuit of a vehicle having an engine compartment and a passenger compartment which are separated by an apron (22) comprises: PA0 a vacuum booster (16) having one axis (18) and including: PA1 an actuating rod (20) projecting into the passenger compartment; PA1 a shell (14) which is intended to be fastened by its periphery to the apron (22) in the engine compartment and to which a master cylinder (10) is fastened; and PA1 a cover (26) closing the shell and bearing circumferentially on the apron (22) in the engine compartment, PA0 a pedal unit for actuating the booster, including at least one pedal (30) mounted on a lever (32), the pivot (34) of which is retained by a bearing piece (36) fixed to the cover. The projection of the pivot (34) in the plane of fastening of the assembly to the apron (22) is located within the perimeter of the orifice of the apron, so as to transmit substantially the entirety of the force exerted by the lever (32) on the pivot (34) in a direction substantially parallel to the axis (18) of the booster (16) in order to oppose the tearing force generated between the assembly and the apron (22) during the actuation of the pedal unit.

BACKGROUND OF THE INVENTION 
The present invention relates to a control assembly for a hydraulic circuit 
of a vehicle having an engine compartment and a passenger compartment 
which are separated by an apron, the assembly comprising: 
a vacuum booster having one axis and including: 
an actuating rod projecting into the passenger compartment, 
a shell which is intended to be fastened by its periphery to the apron in 
the engine compartment and to which a master cylinder is fastened, and 
a cover closing the shell and bearing circumferentially on the apron in the 
engine compartment, 
a pedal unit for actuating the booster, including at least one pedal 
mounted on a lever, the pivot of which is retained by a bearing piece 
fixed to the cover. 
Similar assemblies are known, for example, from the documents 
FR-A-2,216,154 and EP-A-0,104,105. In these examples, an intermediate 
fastening plate is provided between the pedal unit and the booster. In 
fact, the forces generated during a breaking operation both at the 
fastening points of the booster to the plate and at the fastening point of 
the bearing piece of the pedal pivot are very high, and it is necessary to 
reinforce the apron of the vehicle correspondingly by means of this plate. 
U.S. Pat. No. A-4,469,008 also makes known a booster for a motor cycle, 
having a bearing piece fixed to the cover. It also possesses a reaction 
piece absorbing the forces, with the result that a fastening apron is not 
necessary. However, the two pieces tend to exert torsion on the booster. 
SUMMARY OF THE INVENTION 
An object of the present invention is to overcome this disadvantage by 
means of an assembly not needing such a plate and therefore to make the 
assembly lighter. 
According to the present invention, the projection of the pivot in the 
plane of fastening of the assembly to the apron is located within the 
perimeter of the orifice of the apron, so as to transmit substantially the 
entirety of the force exerted by the lever on the pivot in a direction 
substantially parallel to the axis of the booster in order to oppose the 
tearing force generated between the assembly and the apron during the 
actuation of the pedal unit. 
Preferably, according to the invention, the cover has a radial 
protuberance, to which is fastened a pressure generator controlled by a 
second pedal unit, the bearing piece of which is fixed to the cover. 
Likewise preferably, the pressure generator is a clutch-release 
transmitter, the cylinder of which forms one piece with the protuberance.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to FIG. 1, an average person skilled in the art will 
recognize the master cylinder 10, equipped with its reservoir 12, fastened 
to the shell 14 of the booster 16 in the axis 18 of the booster equipped 
with its actuating rod 20. The shell 14 is fastened on its periphery to 
the apron 22 of the vehicle, for example by means of screws 24 in the 
engine compartment. 
The shell of the booster 16 is closed by means of a cover 26 bearing with 
its periphery 28 on the apron 22 in the engine compartment. 
FIG. 2 illustrates as a particular example another mode of fastening of the 
shell 14 to the apron 22, according to which an intermediate rigid disk 
29, the central orifice of which interacts with the cover 26, is used. The 
outer peripheral edge 38 of the disk 29 can thus advantageously be curved 
to form a support for the unrolling diaphragm 25 of the booster. 
Alternatively, it is also possible for the disk 29 and the cover 26 to 
form only one piece. 
It is also possible for the shell 14 to be fastened to the apron 22 by 
means of the cover 26. 
The actuating rod 20 of the booster projects into the passenger compartment 
of the vehicle. A pedal 30 is mounted on a lever 32 having a pivot 34, the 
actuating rod 20 of the booster 16 being fastened to the lever 32 between 
the pedal 30 and the pivot 34. The pivot 34 is retained by a bearing piece 
36 fixed to the cover 26. As can be seen, the projection of the pivot in 
the plane of fastening of the assembly to the apron is located within the 
perimeter of the orifice of the apron. 
When the driver of the vehicle so equipped presses on the pedal 30, the 
force which he exerts is applied to the actuating rod 20 of the booster 
16, multiplied by the ratio of the lever 32. This force is transmitted to 
the piston of the master cylinder 10, further multiplied by the boost 
factor of the booster. A force tearing the shell 14 at its fastening 
points to the apron 22, directed substantially parallel to the axis 18 and 
towards the engine compartment, is therefore generated. 
However, the force applied to the lever generates on the pivot 34 a force 
substantially parallel to the axis 18 and directed towards the passenger 
compartment and therefore opposed to the preceding force. This force is 
transmitted to the cover 26 by the bearing piece 36. The cover 26, made of 
sufficiently rigid material, distributes this force to its periphery and 
generates on the apron 22, in the region of its periphery 28, a force 
which is therefore opposed to the above-mentioned tearing force. The 
result of this is that the apron 22 is subjected to two opposing forces, 
the resultant of which corresponds substantially to the force exerted by 
the driver. The presence of a plate is therefore no longer necessary. 
According to a preferred embodiment, the bearing piece 36 and the cover 26 
form only one piece which is produced by molding from a material having a 
high resistance and a high resilience, such as a polymer material filled, 
if appropriate, with fibers, for example of glass, and ribbed. Preferably, 
a ring 37 forming a support for the unrolling diaphragm of the booster 16 
is also integrated in the bearing piece 36 and in the cover 26. 
Of course, an average person skilled in the art can make many modifications 
to the present invention, without departing from its scope, as defined by 
the accompanying claims. 
For example, a second bearing piece, such as the piece 36, can also be 
integrated in the cover 26 in order to carry the pivot of another lever 
equipped with a pedal. 
In FIGS. 3 and 4, it can be seen that the cover 26 has a radial 
protuberance 40, to which a clutch-release transmitter 42 is fastened. 
The cylinder 44 of this transmitter forms one piece with the protuberance 
40. 
The piston of the transmitter 42 is connected by means of a pusher 46 to an 
actuating pedal unit including a pedal 48 mounted on a lever 50, the pivot 
52 of which is retained by a bearing piece 54 fixed to the cover 26. 
It will also be possible for the supporting piece of the steering column 
likewise to be integrated in the cover 26.