Disc Brake Rotary-to-Linear Conversion Mechanism
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Solution Overview
Problem
Existing disc brake mechanisms for holding braking force during parking brake application are complex, leading to decreased manufacturing efficiency.
Innovation Solution
A disc brake design incorporating a simplified mechanism using a rotary-to-linear conversion system with a ball-and-ramp mechanism, which includes a rotation transmission member, a shaft member with threads, and a ball-and-ramp mechanism to apply thrust to the piston for holding the braking position, allowing for efficient manufacturing and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex mechanism for holding braking force is used, then the braking force can be held during parking brake application, but the manufacturing efficiency decreases
Solution Approach 1:
The mechanism is divided into two independent thread fittings: a first thread fitting between the adjuster nut and shaft member, and a second thread fitting between the shaft member and brake pad assembly. This segmentation allows each thread to be optimized independently, simplifying manufacturing while maintaining the braking force holding capability through the differential friction torque design.
Solution Approach 2:
Different friction torques are applied at different locations of the shaft member through the two thread fittings. The first thread has a larger rotation friction torque than the second thread, creating a local quality difference that enables the shaft member to rotate selectively. This local differentiation simplifies the overall mechanism by eliminating the need for complex one-way clutch assemblies while maintaining reliable braking force holding.
2Productivity
If a simplified mechanism is used, then manufacturing efficiency increases, but the mechanism for holding braking force becomes insufficient
Solution Approach 1:
The friction torque parameters of the two thread fittings are specifically designed with different values. The first thread is designed with a larger rotation friction torque than the second thread, creating a parameter difference that enables the shaft member to rotate in the brake pad pressing direction during brake release. This parameter change approach maintains reliable braking force holding while significantly simplifying the mechanism structure for improved manufacturing efficiency.
3Reliability
If a complex rotation restriction mechanism is used, then the shaft member rotation can be controlled, but the device complexity increases
Solution Approach 1:
The shaft member's rotation control is achieved through the inherent friction torque differences of the two thread fittings rather than through an external rotation restriction mechanism. The first thread's larger friction torque automatically prevents the shaft member from rotating in the reverse direction during normal operation, while the second thread's smaller friction torque allows controlled rotation during brake release. This self-service approach eliminates complex one-way clutch or ratchet mechanisms, reducing device complexity while maintaining reliable rotation control.
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
The solution provides a simplified mechanism for holding braking force during parking brake application, increasing manufacturing efficiency and reducing operational noise while maintaining effective braking performance.
Implementation Method 1
a shaft member threadedly fitted to the rotation transmission member so that a rotation and linear motion of the shaft member are enabled; and a ball-and-ramp mechanism threadedly fitted to the shaft member
Implementation Method 2
a ball-and-ramp mechanism threadedly fitted to the shaft member, which is configured to apply a thrust in the axial direction to the piston through the rotation of the shaft member
Implementation Method 3
a rotation friction torque of the first thread is larger than a rotation friction torque of the second thread
Data Source
AI summary
A rotary-to-linear conversion mechanism includes a rotation transmission member, a shaft member threadedly fitted to the rotation transmission member so that a rotation and linear motion of the shaft member are enabled, and a ball-and-ramp mechanism threadedly fitted to the shaft member, which is configured to apply a thrust in the axial direction to a piston through the rotation of the shaft member. The shaft member includes a first thread formed on one end side thereof, and a second thread formed on the other end side thereof. A rotation friction torque of the first thread is larger than a rotation friction torque of the second thread.