Motor vehicle master cylinder with device for detecting actuation of a braking system
First Claim
Patent Images
1. A master cylinder (1) for a motor vehicle braking system, comprising:
- a body (2) made of non-magnetic material;
a bore (3) located in the body (2) of the master cylinder;
a variable-volume pressure chamber (5) within the bore (3);
a piston (34) located in the bore that slides therein for varying the volume of the pressure chamber (5); and
a detection device (9) fixed to the body (2) of the master cylinder and facing the bore for detecting actuation of the braking system corresponding to movement of the piston, said detection device having first circuit and a second circuit that are opened or closed by a magnetic piece (19) carried by the piston (4), characterized in that said first magnetic circuit is defined by a first pole piece (29) having a first gap (26) formed with the magnetic piece (19), a second pole piece (30) having a second gap (27) formed with the magnetic piece (19) and a magnet (32) located between the first and second pole pieces such that when said piston is in a rest position a residual magnetic flux flows in said first magnetic circuit by way of said first and second air gaps and said second magnetic circuit is defined by a third pole piece (31) having a third gap (25) formed with the magnetic piece (19) and a fourth gap (24) formed between said first pole piece (29) and said third pole piece (31) and a magnetic-field-variation sensor (28) that is isolated from said residual magnetic flux flow in said first magnetic circuit by said third gap and said fourth gap when the piston (34) is in the rest position and only when the piston moves is the magnetic-field-variation sensor (28) closed and magnetic flux flow occurs in the second magnetic circuit to provide an indication of the movement of the piston (34).
1 Assignment
0 Petitions
Accused Products
Abstract
The invention proposes a master cylinder 1 with a device for detecting actuation of a braking system. The detection device is fixed to a body 2 of the master cylinder 1 at a pressure chamber 5. The detection device comprises a magnetic circuit 9 able to be opened and closed by a moving magnetic piece 19. The moving magnetic piece 19 is, for example, fixed to a piston 4 of the master cylinder 1. Actuation of a brake pedal causes the piston 4 and the moving piece 19 to advance in the master cylinder 1. The magnetic circuit 9 therefore changes state (opened or closed). The change in state of the magnetic field switches the brake lights on and off.
27 Citations
6 Claims
-
1. A master cylinder (1) for a motor vehicle braking system, comprising:
-
a body (2) made of non-magnetic material; a bore (3) located in the body (2) of the master cylinder; a variable-volume pressure chamber (5) within the bore (3); a piston (34) located in the bore that slides therein for varying the volume of the pressure chamber (5); and a detection device (9) fixed to the body (2) of the master cylinder and facing the bore for detecting actuation of the braking system corresponding to movement of the piston, said detection device having first circuit and a second circuit that are opened or closed by a magnetic piece (19) carried by the piston (4), characterized in that said first magnetic circuit is defined by a first pole piece (29) having a first gap (26) formed with the magnetic piece (19), a second pole piece (30) having a second gap (27) formed with the magnetic piece (19) and a magnet (32) located between the first and second pole pieces such that when said piston is in a rest position a residual magnetic flux flows in said first magnetic circuit by way of said first and second air gaps and said second magnetic circuit is defined by a third pole piece (31) having a third gap (25) formed with the magnetic piece (19) and a fourth gap (24) formed between said first pole piece (29) and said third pole piece (31) and a magnetic-field-variation sensor (28) that is isolated from said residual magnetic flux flow in said first magnetic circuit by said third gap and said fourth gap when the piston (34) is in the rest position and only when the piston moves is the magnetic-field-variation sensor (28) closed and magnetic flux flow occurs in the second magnetic circuit to provide an indication of the movement of the piston (34). - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification