Caliper Brake Seal Structure to Prevent High-Pressure Drag

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Solution Overview

Problem

Conventional caliper brakes experience a drag phenomenon due to premature deformation of the seal member during high pressure braking, leading to increased braking fluid requirements, invalid stroke, and reduced pedal feel.

Innovation Solution

The caliper brake incorporates a seal member with a protrusion and a seal groove design that allows for controlled elastic deformation, preventing premature deformation and ensuring smooth rollback performance even under high pressure braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the elastic deformation movable range of the seal member is increased by expanding the inclined surface of the seal groove, then the rollback performance is improved, but the required amount of braking fluid increases leading to increased invalid stroke and reduced pedal feel

Engineering Contradiction:
Improverollback performanceVSAvoidbraking fluid amount
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The seal member is designed with non-uniform thickness, where the front surface has a smaller thickness than the middle portion. This local variation in thickness allows the seal member to provide sufficient elastic deformation for rollback while maintaining a compact overall structure that does not require excessive braking fluid volume.

Inventive Principle:
Principle #3Local quality

2Reliability

If the elastic deformation movable range of the seal member is increased, then the rollback performance is improved, but the invalid stroke increases and pedal feel is reduced

Engineering Contradiction:
Improverollback performanceVSAvoidpedal feel
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By making the front surface thickness smaller than the middle portion thickness, the seal member achieves the necessary elastic deformation capability for complete rollback while maintaining a compact structure. This prevents excessive invalid stroke and preserves good pedal feel during braking operation.

Inventive Principle:
Principle #3Local quality

3Device complexity

If a conventional seal member is used, then the structure is simple, but the piston does not return smoothly causing drag phenomenon

Engineering Contradiction:
Improveseal member structureVSAvoidrollback smoothness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The seal member features a thickness gradient where the front surface is thinner than the middle portion. This local variation enables the seal member to deform elastically during braking and then fully rebound to push the piston back smoothly, eliminating drag phenomenon while maintaining structural simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The seal member's thickness design allows it to dynamically adapt during operation: the thinner front surface enables sufficient elastic deformation under braking pressure, while the thicker middle portion provides structural support. This dynamic behavior ensures smooth piston retraction without drag.

Inventive Principle:
Principle #15Dynamics

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 prevents drag phenomenon, reduces braking fluid requirements, and improves pedal feel by ensuring smooth rollback of the piston, thereby enhancing vehicle fuel efficiency.

Implementation Method 1

the seal member is deformed and restored by elasticity thereof, and the piston, which has moved forward, retracts again to return its original position by the elasticity of the seal member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3988812B1Caliper brake
Publication Date: 2025.08.13 HL MANDO CORP
  • EP3988812B1 patent drawingFigure 1
  • EP3988812B1 patent drawingFigure 2~3
  • EP3988812B1 patent drawingFigure 4~5

AI summary

Disclosed herein a caliper brake includes a carrier in which a pair of pad plates are installed to move forward and backward toward a disk; a caliper housing slidably installed on the carrier and provided with a cylinder; a piston installed in the cylinder and configured to move forward and backward toward the pair of pad plates by a braking hydraulic pressure; a seal groove formed to be recessed in an annular shape on an inner surface of the cylinder; and a seal member accommodated in the seal groove, the seal member including a front surface located in a forward direction of the piston; wherein the front surface is provided with a protrusion from which at least a part thereof protrudes.