Disc Brake Pad Fixation Layout for Clunk Noise Reduction
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Solution Overview
Problem
Disc brake devices often experience clunk noise due to collisions between the pad and pad support member when the braking force is released, as the moments acting on the pads during forward and reverse braking create gaps that lead to vigorous collisions upon release.
Innovation Solution
The disc brake device incorporates a design where the inner and outer pads are fixed only to the tip end portion of the radially outer side piston on the rotation-in side, with the remaining pistons not fixed to the pads, and uses a shim plate with adhesive surfaces to stabilize the pad posture, preventing the formation of gaps and collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pad is supported movably by the pad support member to enable axial movement, then the pad can press against the rotor for braking, but the pad and pad support member collide when braking force is released causing clunk noise
Solution Approach 1:
The patent introduces a damping member as an intermediary element positioned between the pad and pad support member. This damping member absorbs the impact energy when the braking force is released, preventing direct collision between the pad and pad support member, thereby eliminating clunk noise while preserving the necessary axial movement for braking operation.
Solution Approach 2:
The damping member is pre-installed in the damping member receiving portion of the pad support member before the pad is assembled. This beforehand cushioning ensures that when the braking force is released and the pad moves axially, the damping member is already in place to cushion the impact, preventing clunk noise from the collision between pad and pad support member.
2Force
If multiple pistons are used to press the pad, then braking force is improved, but fixing all pistons to the pad creates complexity and potential collision issues
Solution Approach 1:
The patent applies local quality by differentiating the fixation status of different pistons. Specifically, only the first piston among multiple pistons is fixed to the pad, while the second piston and subsequent pistons are not fixed to the pad. This selective fixation reduces device complexity and prevents collision issues while still providing sufficient braking force through the combined action of all pistons.
Solution Approach 2:
The patent segments the piston group into fixed and non-fixed portions. The first piston is segmented as the fixed element attached to the pad, while the second and subsequent pistons are segmented as non-fixed elements that can move independently. This segmentation simplifies the overall structure and reduces collision risks while maintaining effective braking force application.
Data Source
AI summary
A disc brake device includes a pair of pads, a pad support member supporting at least one of the pair of pads in a movable manner in an axial direction, and a plurality of pistons configured to press the one of the pads toward the rotor in the axial direction. Slide engagement portions engaged with the pad support member so as to be movable in the axial direction are respectively provided at both side portions of the one of the pads in a circumferential direction. The one of the pads is fixed to a tip end portion of at least one piston including a piston arranged at an end portion on a rotation-in side or a rotation-out side among the plurality of pistons, and is not fixed to a tip end portion of a remaining piston.