Vehicle Disc Brake Pad Return Spring and Guide Groove Design
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Solution Overview
Problem
Existing vehicle disc brake systems face issues with brake noise or squeal due to complex configurations and increased production costs, and they often fail to maintain effective friction pad movement away from the disc rotor as the pad wears, affecting braking performance.
Innovation Solution
A vehicle disc brake design featuring a caliper body with pad guide grooves, friction pads with lug pieces, and a pad return spring that includes a locking portion, a spring portion formed by bending an extending piece, and an abutment portion, where the space between the lug piece and pad guide groove is positioned to align with the friction pad's gravity center and piston center, allowing for controlled movement and reduced noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pad return spring with a retainer portion and curved pad return portion is used to guide the friction pad and bias it away from the disc rotor, then the friction pad can be properly positioned and biased when the brake is released, but the configuration becomes complex and production costs increase
Solution Approach 1:
The invention extracts the guiding function from the pad return spring by providing separate pad guide grooves in the caliper support arms. This allows the pad return spring to be simplified to only perform its primary function of biasing the friction pad away from the disc rotor, reducing overall system complexity while maintaining proper friction pad positioning
Solution Approach 2:
The invention divides the functions of friction pad support into separate components: pad guide grooves for guidance and a simplified pad return spring for biasing. This segmentation allows each component to be optimized independently, reducing the complexity of the pad return spring configuration
2Reliability
If the pad return spring uses a complex curved pad return portion to achieve proper biasing, then the friction pad can be biased away from the disc rotor when released, but brake noise or squeal may be generated due to insufficient fixing of lug pieces in pad guide grooves
Solution Approach 1:
The invention extracts the noise-causing spring force from the friction pad biasing function by providing separate pad guide grooves that positively guide the lug pieces. This allows the pad return spring to apply biasing force without the complex curved configuration that previously caused insufficient lug piece fixing, thereby eliminating brake noise and squeal
Solution Approach 2:
The pad guide grooves act as an intermediary mechanism between the lug pieces and the simplified pad return spring. The grooves provide the necessary guidance and fixing of the lug pieces, while the spring simply provides the biasing force, separating the guiding function from the biasing function to prevent noise generation
3Reliability
If the biasing force of the pad return spring increases with displacement amount, then the friction pad is biased away from the disc rotor when released, but the friction pad retreats greatly when fully worn, affecting brake pedal operation feeling
Solution Approach 1:
The invention changes the geometric parameters of the pad return spring, specifically making the extending piece thinner towards the distal end. This parameter change reduces the spring's stiffness and displacement, allowing it to provide sufficient biasing force for friction pad retraction while maintaining consistent brake pedal operation feeling even when the friction pad is fully worn
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 design effectively restricts brake noise and squeal while ensuring the friction pad moves away from the disc rotor with a simple configuration, maintaining optimal braking performance from new to fully worn pads by adjusting the biasing force of the pad return spring.
Implementation Method 1
a spring portion (11c) formed by bending back an extending piece (11c1) which extends from the locking portion (11a) via a curved portion (11b)
Data Source
AI summary
One embodiment provides a vehicle disc brake including: a caliper body; a caliper bracket having a pair of caliper support arms; a pair of friction pads; and a pad return spring. Each caliper support arm has a pair of pad guide grooves, and a pair of lug pieces extending from the friction pad are supported movably therein. An outer surface of each lug piece is stepped such that a projecting length on a radially outer side is shorter than a projecting length on a radially inner side, thereby defining a space portion between the lug piece and the pad guide groove. A first imaginary line, which is defined to pass a gravity center of the friction pad and to intersect perpendicularly a center line connecting a center of a disc rotor and a center of a piston, passes the space.