Brake Caliper Helical Connection for Coaxial Piston Assembly

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Solution Overview

Problem

The existing helical connection mechanism in electromechanical disc brake calipers is irreversible and prone to misalignment during assembly, complicating the connection between the drive member and electric motor, making the assembly process difficult.

Innovation Solution

A helical connection mechanism with a sleeve and drive member that includes rotation stopping and axial holding means, such as a plate with axial extensions and radial shapes, to ensure the sleeve and drive member remain coaxial with the piston, preventing rotation and maintaining alignment, which are manufactured by cutting, folding, and stamping from a sheet metal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional helical linkage mechanism is used, then the brake system achieves irreversible braking force transmission, but the assembly process becomes complex due to misalignment between the drive member and electric motor

Engineering Contradiction:
Improveirreversible braking force transmissionVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The plate with axial extensions and radial shapes is pre-formed to include both alignment and anti-rotation features. The axial extensions are positioned to automatically align the drive member with the electric motor shaft during assembly, while the radial shapes prevent rotation. This preliminary configuration of alignment features eliminates the need for complex alignment procedures during assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The plate serves multiple functions simultaneously: it provides axial extensions for alignment, radial shapes for anti-rotation, and structural support for the helical linkage. By combining alignment and anti-rotation features into a single component, the design reduces the number of separate parts and simplifies the overall assembly process while maintaining the irreversible braking function.

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

2Manufacturing precision

If alignment features are added to prevent misalignment, then assembly precision improves, but the device structure becomes more complex

Engineering Contradiction:
Improvealignment precisionVSAvoidstructural complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment features (axial extensions) and anti-rotation features (radial shapes) are merged into a single plate component. This consolidation ensures precise alignment between the drive member and electric motor while preventing rotation, all through one integrated structure rather than multiple separate alignment devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plate incorporates localized features at specific positions: axial extensions at the periphery for alignment with the electric motor shaft, and radial shapes at appropriate locations for anti-rotation. Each local feature performs a specific function, achieving high alignment precision without requiring the entire structure to be complex.

Inventive Principle:
Principle #3Local quality

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 solution simplifies the assembly process by ensuring precise alignment and rotation locking, reducing assembly complexity and costs, while enhancing the stability and ease of integration with the electric motor.

Implementation Method 1

the actuator has an output shaft coupled to a drive element or actuating member that forms part of a helical linkage located within the cylindrical housing and partly within the piston, interposed between the actuator and the piston head. When the actuator is activated, it exerts torque via its output shaft, which is converted into pressing force by a helical linkage mechanism

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

the caliper having a caliper body which carries two pads on either side of the disc and which is equipped with an electromechanical actuator to press these pads against the disc when activated, in order to generate a braking torque

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4107406B1Helical connection mechanism for electromechanical brake caliper piston with simplified mounting and method of manufacturing such a mechanism
Publication Date: 2024.04.24 HITACHI ASTEMO FRANCE
  • EP4107406B1 patent drawingFigure 1~2
  • EP4107406B1 patent drawingFigure 3~4
  • EP4107406B1 patent drawingFigure 5

AI summary

The invention relates to a helical connection mechanism for an electromechanical brake piston configured to be mounted inside the piston, comprising a bushing (13) and a drive member (9) cooperating via a helical connection with longitudinal axis (AX), and means (14) for blocking the rotation of the bushing relative to the piston about the longitudinal axis (AX) and for axially retaining the mechanism, said means comprising a plate (28) secured on the bushing (13) and extending orthogonally to the longitudinal axis (AX), at least three axial extensions (32) cooperating with an axial wall of the piston and at least one radial shape (40) cooperating with the axial wall of the piston.