Brake Caliper Axial Shortening via Bellows Sealing Boot
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Solution Overview
Problem
Previous brake caliper designs that aim to shorten the axial length compromise the freedom of deformation of the sealing boot, limiting space-saving measures in hybrid electric and electric vehicles.
Innovation Solution
A brake caliper design featuring a piston seal, a movable piston with a cylindrical outer surface, a heat shield with an attachment portion at least 2 mm radially outward from the piston, and a sealing boot with a bellows-shaped portion, allowing for axial shortening while maintaining sufficient deformation freedom, and a method of manufacturing this configuration using cross-linkable rubber and a heat shield with enhanced adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the axial length of the brake caliper is shortened, then the space for hybrid electric and electric vehicles is saved, but the freedom of deformation of the sealing boot is compromised
Solution Approach 1:
The sealing boot is configured with a bellows-shaped structure that expands radially outward from the piston, utilizing the radial dimension to provide deformation freedom. The bellows extends radially with multiple turns that can deform axially and radially, allowing the sealing boot to accommodate piston movement and thermal expansion without requiring increased axial length of the caliper.
Solution Approach 2:
The bellows-shaped sealing boot is nested around the piston, with the piston positioned within the central cavity of the bellows structure. This nested configuration allows the sealing boot to deform around the piston while maintaining a compact axial profile, as the bellows can compress and expand radially without significantly increasing the axial length of the caliper assembly.
2Device complexity
If the sealing boot is compressed radially with walls extending axially, then the brake caliper structure is simplified, but the axial shortening is limited
Solution Approach 1:
Instead of having the sealing boot walls extend axially, the invention configures the sealing boot with a bellows-shaped structure that primarily extends radially from the piston. The bellows has multiple turns that create a compact axial profile while providing sufficient deformation freedom through radial and axial movement of the bellows walls.
Solution Approach 2:
The sealing boot is designed as a flexible bellows-shaped structure with thin walls that can deform axially and radially. The bellows configuration allows the flexible material to accommodate piston movement and thermal expansion while maintaining a short axial length, as the flexible walls can compress and expand without requiring significant axial space.
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 achieves axial shortening of the brake caliper while ensuring sufficient sealing boot deformation, reducing storage space and maintaining effective sealing and heat shielding, thus optimizing brake performance and aerodynamics.
Implementation Method 1
the mold, which has been pre-heated to a temperature sufficient to cross-link the rubber, causes the rubber to simultaneously cross-link in the shape of the sealing boot and cross-link adhere to the heat shield
Implementation Method 2
a heat shield disposed at an axial end of the piston
Data Source
AI summary
A brake caliper apparatus includes a caliper portion configured to be supported by a vehicle, a piston seal disposed in an annular cavity of the caliper portion, a piston disposed in a cylindrical recess in said caliper portion and having a cylindrical outer surface in sealing contact with the piston seal, the piston being movable within said cylindrical recess along an axial direction, a heat shield disposed at an axial end of the piston, and a sealing boot having a first end attached to the heat shield at an attachment portion of the heat shield and a second end engaged to the caliper portion at an engagement portion of the caliper portion, the piston seal and the engagement portion being on a common plane perpendicular to the axial direction.