Disk Brake Parking Screw Centering Mechanism
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Solution Overview
Problem
The existing designs of hydraulically operated disk brakes with electromechanical parking brakes face mounting difficulties due to indeterminate transverse positions of the screw's rear section, leading to potential damage and assembly impossibilities when the screw's rear extremity contacts the cavity's bottom or annular seal during assembly.
Innovation Solution
The integration of centering means, such as truncated cones or spheres, between the piston and screw ensures radial centering of the screw in a predetermined mounting position, facilitating coaxial alignment and secure assembly by interacting convex and concave surfaces, and angular abutment features to determine the screw's axial position, allowing for precise axial introduction and secure mounting within the brake caliper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the screw's rear section is allowed to move freely during assembly, then the assembly process is simpler, but the transverse position becomes indeterminate causing mounting difficulties and potential damage
Solution Approach 1:
The patent applies preliminary action by providing preliminary centering of the screw's rear section relative to the piston through centering means (such as a conical centering element) before the actual mounting operation. This preliminary positioning ensures that when the assembly is introduced axially into the cavity, the screw is already properly aligned, preventing mounting difficulties and damage while maintaining assembly simplicity.
2Reliability
If the screw is secured axially to the bottom wall during operation, then the parking brake function is reliable, but the assembly process becomes more complex requiring precise alignment
Solution Approach 1:
The patent resolves this contradiction by performing the alignment action in advance through the centering means, so that when the assembly is introduced axially, the screw is automatically positioned correctly relative to the bottom wall. This preliminary centering eliminates the need for complex real-time alignment procedures during assembly, reducing assembly complexity while ensuring the screw can be reliably secured for parking brake operation.
Solution Approach 2:
The centering means acts as an intermediary element between the screw and the piston/bottom wall assembly. This intermediary component facilitates the transition from a free-moving state during assembly to a precisely positioned state for operation, enabling both easy assembly and reliable parking brake function without requiring complex alignment procedures.
3Ease of operation
If clearances are provided for screw rotation, then the screw can rotate freely for parking brake operation, but the transverse position becomes indeterminate causing contact issues during assembly
Solution Approach 1:
The patent applies preliminary action by establishing the correct transverse position of the screw relative to the piston through centering means before assembly begins. This preliminary centering ensures that when clearances are provided for screw rotation during parking brake operation, the screw starts from a known, correct position, preventing contact issues with the bottom wall or annular seal during assembly while maintaining the necessary rotation freedom for operation.
Data Source
AI summary
The invention proposes an arrangement containing a brake piston (16) for the operation of at least one disk brake pad and a nut-and-screw unit (44, 46) for producing an axial thrust, from the rear to the front, of the piston (16) containing a nut (46) that is arranged in the interior (33) of the piston (16), in relation to which it is secured in order to prevent rotation, and inside which it is mounted so as to slide axially, the front axial end face (52) of which interacts with an internal section (54) facing the front wall of the piston (16) in order to push the piston axially (16) towards the front when the screw (44) is driven in a rotating manner in the direction of unscrewing, and a screw (44) containing a front section screwed into the nut (46), an intermediate radial flange and a rear section (66), characterized in that the piston (16) and the screw (44) contain means of centering (90, 92) that interact with one another when the screw (44) is in a predetermined front axial mounting position in relation to the piston (16) in order to center the rear section (66) of the screw (44) radially in relation to the piston (16).