Disk Brake Caliper Friction Stir Welding Finish Position

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Solution Overview

Problem

The existing methods of manufacturing disk brakes using friction stir welding often result in bulges that block brake fluid flow, leading to reduced pressure capacity and performance issues in caliper systems.

Innovation Solution

Optimizing the finish position of friction stir welding to prevent bulges from obstructing brake fluid flow, thereby improving the pressure capacity and design performance of the caliper by ensuring the welding finish is out of alignment with communication passages, and using a single tooling setup for both left and right-side installations to enhance manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If friction stir welding is used to join the cover member to the caliper body, then the joining strength is improved, but bulges are generated that block brake fluid flow through communication passages

Engineering Contradiction:
Improvejoining strengthVSAvoidbulge blocking brake fluid flow
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The welding tool performs friction stir welding only in specific local areas (cylinder portions) rather than across the entire caliper body. By controlling the welding path to avoid communication passages and positioning welds in localized zones, the method maintains joining strength while preventing bulges from blocking brake fluid flow paths.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Communication passages are formed in advance through the caliper body before the friction stir welding process. This preliminary action ensures that the passages are established at positions that will not be blocked by subsequent welding bulges, allowing brake fluid flow to remain unobstructed after welding is completed.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If friction stir welding is performed across the entire caliper body, then the structural integrity is improved, but the pressure capacity is reduced due to bulges blocking fluid flow

Engineering Contradiction:
Improvestructural integrityVSAvoidpressure capacity
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

Instead of welding the entire caliper body, the method applies friction stir welding selectively to specific cylinder portions where joining is required. This localized approach maintains structural integrity at critical joints while avoiding the creation of bulges in areas that would compromise pressure capacity and brake fluid flow.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The caliper body is divided into distinct functional zones: cylinder portions requiring welding for structural integrity, and communication passage areas that must remain free of bulges. By segmenting the welding operation to affect only specific portions, the method preserves both structural integrity and pressure capacity.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If different tooling setups are used for left and right-side installations, then the manufacturing precision is improved, but the device complexity and manufacturing time increase

Engineering Contradiction:
Improveinstallation precisionVSAvoidtooling setup complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The friction stir welding process creates asymmetric bulge patterns relative to the welding direction. By controlling the welding direction and finish position, the method ensures that bulges are generated in consistent relative positions regardless of whether the caliper is installed on the left or right side, allowing a single symmetric tooling setup to achieve proper alignment for both installations.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

A single tooling setup is designed to accommodate both left-side and right-side caliper installations. The friction stir welding process and tooling are configured to produce consistent bulge positions relative to the caliper geometry, enabling the same tooling to correctly position communication passages for both mirror-image installations without requiring separate setups.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach prevents fluid flow blockages and enhances the pressure capacity of the caliper, improving the overall performance of the disk brake while simplifying the manufacturing process by allowing the same tooling settings for both left and right-side installations.

Implementation Method 1

an opposed-type caliper body (5) including a cylinder portion (10, 11) and a bridge portion (12) connecting the cylinder portions (10, 11), wherein outer circumferential edges of opposite ends of a cylinder portion (10, 11) from the other include a circular arc portion convexed to an outer side in a radial direction of a disk (2), linear portions extending in a manner inclined to the outer side in the radial direction of the disk (2) in a direction away from each other at respective sides of the circular arc portion in the rotational direction of the disk (2), circular arc portions convexed to the outer side in the radial direction of the disk (2) at respective sides of the linear portions in the rotational direction of the disk (2), linear portions extending in a manner inclined to the inner side in the radial direction of the disk (2) at respective sides of the circular arc portions in the rotational direction of the disk (2), circular arc portions convexed to the inner side in the radial direction of the disk (2), and a circular arc portion connecting positions of the circular arc portions nearest to each other and convexed to the outer side in the radial direction of the disk (2)

Methodology Applied
Scientific EffectFriction stir welding: Friction Welding

Data Source

PatentEP2270352B1Disk brake
Publication Date: 2012.09.05 HITACHI AUTOMOTIVE SYST LTD
  • EP2270352B1 patent drawingFigure 1~2
  • EP2270352B1 patent drawingFigure 3~4
  • EP2270352B1 patent drawingFigure 5~6

AI summary

A disk brake disk capable of reducing a problem with the performance regarding fluid pressure. Cylinders (57,59) include cover members (94.95) of bottoms (62,63), and openings (91,92) configured to be closed by welding the cover members (94,95) thereto by friction stir welding. Finish positions (111a,113a) of the friction stir welding are disposed at the outer circumferential side of the cylinders (57,59) offset from welding tracks (110,112) of the friction stir welding, the position being out of alignment in the circumferential direction of the cylinders (57,59) with the position where a passage (52e,54e,148,148e) in communication with the cylinders (57,59) is formed.