Electric Parking Brake Shim Radial Force Buffering
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Solution Overview
Problem
In electric parking brake devices, relative rotation between the shim and piston can cause damage due to unbuffered radial forces during parking brake operation, leading to potential damage to the piston seal or piston boot.
Innovation Solution
The electric parking brake device incorporates a parking brake actuator that converts rotational movement into linear movement, using inner and outer shims with specific engaging parts and hooks to restrict relative rotation and allow radial movement, thereby buffering radial forces and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the outer shim is rigidly fixed to the outer brake pad, then relative rotation is restricted, but radial forces cannot be buffered causing damage to the electric parking brake device
Solution Approach 1:
The outer shim is designed with dynamic characteristics, allowing it to rotate slightly relative to the outer brake pad during parking brake operation. This controlled movement enables the shim to buffer radial forces while maintaining sufficient rotational restriction to prevent excessive movement. The dynamic design resolves the contradiction by allowing both rotation restriction and force buffering simultaneously.
2Reliability
If the outer shim is allowed to move freely relative to the outer brake pad, then radial forces can be buffered, but relative rotation causes damage to the electric parking brake device
Solution Approach 1:
The engagement strength between the outer shim and outer brake pad is optimized to a specific parameter range. The shim is neither rigidly fixed nor completely free, but engaged with controlled movement capability. This parameter optimization allows the system to simultaneously achieve rotation restriction and radial force buffering, resolving the technical contradiction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration restricts relative rotation and buffers radial forces, effectively preventing damage to the piston seal or piston boot during parking brake operations, enhancing the device's durability.
Implementation Method 1
Each outer has a set spring constant that is set to allow the outer shim to move in the radially outer direction side with respect to the outer brake pad while a parking brake that generates the braking force is performed
Data Source
AI summary
An electric parking brake device includes an inner engaging part formed on an inner shim, wherein the engaging part engages with a projection projecting from the back face of an inner brake pad so that mutual rotation about the central axis of a piston is controlled. An outer hook is formed on an outer shim, wherein the outer hook slidably locks to the outer circumferential edge of an outer brake pad. The outer hook is configured so that at least one of same is provided on each of an outer circumferential end on the outside of and an outer circumferential end on the inside of the outer brake pad in the radial direction and so that the set spring constant allows the outer shim to move to the outside in the radial direction with respect to the outer brake pad while the parking brake is applied.