Piston roll back device
First Claim
1. A piston retracting device for a brake caliper, said brake caliper comprising a caliper body located astride a brake disc having a rotational axis and opposite friction surfaces and pads slidably supported by said caliper body for axial movement relative to the brake disc to engage said opposite friction surfaces, respectively, said caliper body having a piston seat and a piston having a side surface slidably disposed within said piston seat for urging at least one of said pads against said brake disc friction surfaces when brake fluid in said seat is pressurized, wherein said piston retracting device comprises:
- at least one elastic member arranged with a first radial surface thereof bearing against said piston side surface, and with a second radial surface thereof bearing against the caliper body;
said elastic member comprising a third axial surface facing away from said pads and adapted to be affected by the brake fluid;
said elastic member comprising a fourth axial surface facing the pads;
said fourth surface facing an abutment surface on the caliper body adapted to support said elastic member when urged by the pressurized fluid,a portion of said fourth surface facing at least one second chamber arranged radially farther from said piston side surface than said abutment surface,another portion of said fourth surface facing a first chamber arranged in the proximity of the piston side surface, said first chamber being opened towards said piston side surface; and
said abutment surface being radially farther from the piston side surface than said first chamber; and
further comprisinga ring housed in an annular seat and axially sandwiched between said at least one elastic member and the caliper body at the side opposite the elastic member brake fluid,said ring having an inner radial dimension greater than that of said piston so as to leave a clearance between said ring and said piston side surface so as to create said first chamber,said ring comprising a side surface facing said at least one elastic member and providing said abutment surface;
said ring having, in an outer periphery thereof, at least one radial recess axially opened at least at the side facing said at least one elastic member so as to create said at least one second chamber.
2 Assignments
0 Petitions
Accused Products
Abstract
A brake caliper comprising a piston seat (10) wherein a piston (2) slides with its side surface (11) in contact with a radial surface (13) of an elastic member (12). The member further comprising two axial surfaces (15,16) adapted to be affected by a pressurized fluid and being arranged at the piston coming out side facing the pads respectively. The latter surface facing with a portion (17) thereof, a first chamber (18) arranged in the proximity of the piston side surfaces, with another portion (24) thereof, an abutment surface (19) adapted to support said elastic member when it is urged by the pressurized fluid, said abutment surface being radially retracted so as to be farther from the piston side surface than said first chamber and with a further portion (25) thereof, at least one second chamber (20) arranged radially farther from said piston side surface than said abutment surface.
14 Citations
8 Claims
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1. A piston retracting device for a brake caliper, said brake caliper comprising a caliper body located astride a brake disc having a rotational axis and opposite friction surfaces and pads slidably supported by said caliper body for axial movement relative to the brake disc to engage said opposite friction surfaces, respectively, said caliper body having a piston seat and a piston having a side surface slidably disposed within said piston seat for urging at least one of said pads against said brake disc friction surfaces when brake fluid in said seat is pressurized, wherein said piston retracting device comprises:
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at least one elastic member arranged with a first radial surface thereof bearing against said piston side surface, and with a second radial surface thereof bearing against the caliper body; said elastic member comprising a third axial surface facing away from said pads and adapted to be affected by the brake fluid; said elastic member comprising a fourth axial surface facing the pads; said fourth surface facing an abutment surface on the caliper body adapted to support said elastic member when urged by the pressurized fluid, a portion of said fourth surface facing at least one second chamber arranged radially farther from said piston side surface than said abutment surface, another portion of said fourth surface facing a first chamber arranged in the proximity of the piston side surface, said first chamber being opened towards said piston side surface; and said abutment surface being radially farther from the piston side surface than said first chamber; and
further comprisinga ring housed in an annular seat and axially sandwiched between said at least one elastic member and the caliper body at the side opposite the elastic member brake fluid, said ring having an inner radial dimension greater than that of said piston so as to leave a clearance between said ring and said piston side surface so as to create said first chamber, said ring comprising a side surface facing said at least one elastic member and providing said abutment surface; said ring having, in an outer periphery thereof, at least one radial recess axially opened at least at the side facing said at least one elastic member so as to create said at least one second chamber. - View Dependent Claims (2, 3, 4, 5)
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6. A caliper for a disc brake, said brake caliper comprising a caliper body located astride a brake disc having a rotational axis and opposite friction surfaces, pads slidably supported by said caliper body for axial movement relative to the brake disc to engage said opposite friction surfaces, respectively, said caliper body having a piston seat and a piston having a side surface slidably disposed within said piston seat for urging at least one of said pads against said brake disc friction surfaces when brake fluid in said seat is pressurized, wherein said caliper comprises an annular seat adapted to receive a piston retracting device, said piston retracting device comprising:
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at least one elastic member arranged with a first radial surface thereof bearing against said piston side surface, and with a second radial surface thereof bearing against the caliper body; said elastic member comprising a third axial surface facing away from said pads and adapted to be affected by the brake fluid; said elastic member comprising a fourth axial surface facing the pads; said fourth surface facing an abutment surface on the caliper body adapted to support said elastic member when urged by the pressurized fluid, a portion of said fourth surface facing at least one second chamber arranged radially farther from said piston side surface than said abutment surface, another portion of said fourth surface facing a first chamber arranged in the proximity of the piston side surface, said first chamber being opened towards said piston side surface; and said abutment surface being radially farther from the piston side surface than said first chamber; and
further comprisinga ring housed in an annular seat and axially sandwiched between said at least one elastic member and the caliper body at the side opposite the elastic member brake fluid, said ring having an inner radial dimension greater than that of said piston so as to leave a clearance between said ring and said piston side surface so as to create said first chamber, said ring comprising a side surface facing said at least one elastic member and providing said abutment surface; said ring having, in an outer periphery thereof, at least one radial recess axially opened at least at the side facing said at least one elastic member so as to create said at least one second chamber. - View Dependent Claims (7, 8)
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Specification