Disc Brake Piston Boot Geometry to Prevent Reverse Assembly

Solution Overview

Problem

Existing disc brake systems face issues with erroneous assembly of the piston boot, particularly when attaching it to the cylinder, due to the potential for front and back reversal during installation.

Innovation Solution

The disc brake system incorporates a piston boot with an annular fixing part that has distinct diameter regions on its outer peripheral surface, where the larger diameter region abuts against the stepped part of the cylinder, and a smaller diameter region is positioned closer to the cylinder bottom, ensuring proper alignment and preventing reverse assembly by creating a physical and operational feedback mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the piston boot is made with a simple annular fixing part, then the manufacturing is easy and cost-effective, but erroneous assembly occurs due to lack of assembly guidance

Engineering Contradiction:

Improveease of manufactureVSAvoidassembly accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The outer peripheral surface of the annular fixing part is designed with asymmetric diameter regions: a first region with a larger outer diameter and a second region with a smaller outer diameter. This asymmetric configuration creates a unique fit with the corresponding stepped structure in the cylinder, providing tactile and visual feedback that guides correct assembly orientation while maintaining manufacturing simplicity.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The diameter difference between the first and second regions on the outer peripheral surface provides immediate tactile feedback during assembly. When the piston boot is correctly oriented, the larger first region fits into the corresponding larger-diameter portion of the cylinder's stepped structure, while the smaller second region fits into the smaller-diameter portion, confirming proper installation through physical fit and operational feedback.

Inventive Principle:

Principle #23Feedback

2Device complexity

If the piston boot is made with a simple annular fixing part, then the device complexity is low, but erroneous assembly occurs due to lack of assembly guidance

Engineering Contradiction:

Improvedevice complexityVSAvoidassembly accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The outer peripheral surface of the annular fixing part is designed with asymmetric diameter regions: a first region with a larger outer diameter and a second region with a smaller outer diameter. This asymmetric configuration creates a unique fit with the corresponding stepped structure in the cylinder, providing tactile and visual feedback that guides correct assembly orientation while maintaining manufacturing simplicity.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The diameter difference between the first and second regions on the outer peripheral surface provides immediate tactile feedback during assembly. When the piston boot is correctly oriented, the larger first region fits into the corresponding larger-diameter portion of the cylinder's stepped structure, while the smaller second region fits into the smaller-diameter portion, confirming proper installation through physical fit and operational feedback.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the piston boot is made with a simple annular fixing part, then the manufacturing precision requirements are low, but erroneous assembly occurs due to lack of assembly guidance

Engineering Contradiction:

Improvemanufacturing precisionVSAvoidassembly accuracy

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The outer peripheral surface of the annular fixing part is designed with asymmetric diameter regions: a first region with a larger outer diameter and a second region with a smaller outer diameter. This asymmetric configuration creates a unique fit with the corresponding stepped structure in the cylinder, providing tactile and visual feedback that guides correct assembly orientation while maintaining manufacturing simplicity.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The diameter difference between the first and second regions on the outer peripheral surface provides immediate tactile feedback during assembly. When the piston boot is correctly oriented, the larger first region fits into the corresponding larger-diameter portion of the cylinder's stepped structure, while the smaller second region fits into the smaller-diameter portion, confirming proper installation through physical fit and operational feedback.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11486455B2Disc brake and piston boot

Publication Date: 2022.11.01 ASTEMO LTD

AI summary

A piston boot has an annular fixing part that is formed on one end side of a stretchable part and abuts against an inner peripheral side of the cylinder. An outer peripheral surface of the annular fixing part is provided with a first region that abuts against an inner peripheral surface of the cylinder and a second region that is disposed closer to a bottom side of the cylinder than the first region in a piston axial direction. The outer diameter of the first region is larger than the inner diameter of the region of the inner peripheral surface of the cylinder that faces the second region.