Vehicle Disc Brake Caliper Body Piston Seal Positioning
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Solution Overview
Problem
The existing caliper body for vehicle disc brakes has relatively large piston seals that are positioned away from the disc rotor, making it difficult to reduce the size of the caliper body and leading to potential twisting and instability during braking.
Innovation Solution
A caliper body design with a monocoque structure where the acting portions and bridging portion are formed integrally, featuring piston seal mounting grooves centered on the disc rotor side of bolt insertion holes, and with groove widths equal to or narrower than dust seal mounting grooves, to reduce size and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston seals are formed with relatively large widths and positioned away from the disc rotor, then the piston sealing function is improved, but the caliper body size increases and piston stability deteriorates
Solution Approach 1:
The piston seal mounting groove is repositioned from a conventional location to one where its center line in the disc axis direction aligns with the center line of the disc rotor. This spatial reconfiguration allows the piston seals to be positioned closer to the disc rotor, reducing the caliper body's length in the disc axis direction while maintaining sealing effectiveness through optimized groove geometry.
2Ease of operation
If the piston seals are positioned away from the disc rotor, then the piston return function is improved, but the piston stability and resistance to twisting deteriorates
Solution Approach 1:
The piston seal mounting groove is positioned such that its center line in the disc axis direction coincides with the center line of the disc rotor, creating a symmetric and balanced configuration. This alignment ensures that the piston seals act equidistantly on the pistons during return, preventing asymmetric forces that could cause twisting, while still enabling effective piston return functionality.
3Ease of operation
If the caliper body is designed with traditional piston seal positioning, then the piston return mechanism functions properly, but the overall caliper body length in disc axis direction increases
Solution Approach 1:
The piston seal mounting groove is repositioned from a conventional location to one where its center line in the disc axis direction aligns with the center line of the disc rotor. This spatial reconfiguration allows the piston seals to be positioned closer to the disc rotor, reducing the caliper body's length in the disc axis direction while maintaining sealing effectiveness through optimized groove geometry.
Data Source
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AI summary
A caliper body (2) for a vehicle disc brake, acting portions (2a) that are disposed at both-side portions of a disc rotor (3) and that are formed with cylinder holes (2e) are connected by a bridge portion. Bolt insertion holes (2d) are formed at both-side portions, in a disc rotation direction, of one of the acting portions, so as to pass therethrough in a disc radial direction. Dust seal mounting grooves (2f) are fitted are formed in inner surfaces of the cylinder holes on an opening side thereof. Piston seal mounting grooves (2g) are fitted are formed in the inner surfaces of the cylinder holes so as to be closer to a bottom portion of the cylinder hole than the dust seal mounting grooves. A center line (CL1) of the piston seal mounting groove in a disc axis direction is located on a disc rotor side of center axes (CL2) of the bolt insertion holes.