Brake Clearance Adjuster with Expansion Spring Angle Locking

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Solution Overview

Problem

Existing rotation angle control devices for automobile brakes face challenges in achieving rapid and reliable automatic adjustment of brake clearance, as they often require slow compensation mechanisms when the rotation angle exceeds a set value, leading to lagging adjustment and safety issues.

Innovation Solution

A rotation angle control device incorporating an expansion spring and a torsion spring clutch mechanism, which allows for synchronous rotation and self-locking, enabling faster stepless adjustment and minimizing brake clearance fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If unidirectional ratchet teeth meshing mechanism is used for rotation angle control, then the device structure is simple and manufacturing cost is low, but the adjustment speed is slow and there is lag in automatic adjustment function

Engineering Contradiction:
Improveadjustment speedVSAvoiddevice structure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by introducing a torsion spring clutch mechanism that enables dynamic engagement and disengagement of the transmission gear with the clutch gear. The torsion spring allows the system to transition between locked and unlocked states based on rotation angle, enabling rapid adjustment when needed while maintaining simplicity through elastic deformation rather than complex mechanical switches or sensors.

Inventive Principle:
Principle #15Dynamics

2Reliability

If unidirectional ratchet teeth meshing mechanism is used, then the device structure is simple, but the reliability of locking is insufficient and slippage may occur

Engineering Contradiction:
Improvelocking reliabilityVSAvoiddevice structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the curvature principle through the conical friction surfaces of the expansion spring. The conical geometry provides progressive engagement and increased normal force during locking, enhancing friction-based holding capability. The tapered surfaces allow for self-adjusting contact pressure that improves reliability without requiring additional locking elements or complex mechanisms.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent replaces the traditional mechanical ratchet-tooth locking system with a friction-based locking mechanism using expansion springs and conical surfaces. This substitution eliminates the need for precise tooth engagement while providing continuous frictional holding force, improving reliability by avoiding the discrete, stepwise nature of ratchet mechanisms that can slip between teeth.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Force

If wrap spring is used for rotation angle control, then the device structure is simple, but the locking force is insufficient and brake clearance fluctuations increase

Engineering Contradiction:
Improvelocking forceVSAvoiddevice structure complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent applies the composite principle by combining multiple spring mechanisms (torsion spring and expansion spring) with friction surfaces and gear elements to create a composite locking system. The torsion spring provides rotational force while the expansion spring provides radial expansion force, creating a multi-mechanism system that generates significantly higher locking force than a single wrap spring while maintaining relatively simple structure through the integration of these complementary mechanisms.

Inventive Principle:
Principle #40Composite materials

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 solution enables rapid and reliable automatic adjustment of brake clearance, ensuring driving safety by providing a greater locking force and preventing slippage, thus overcoming the limitations of unidirectional ratchets and wrap springs.

Implementation Method 1

an expansion spring (16) sleeved over the mandrel (12) and having an outer circular surface in interfere fit with inner hole surfaces of the first axial counterbore (141) and the second axial counterbore (161)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the outer circular surface of the expansion spring (16) respectively forms friction pairs with the inner hole surfaces of the first axial counterbore (141) of the clutch sleeve (15) and the second axial counterbore (161) of the second worm (18)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3848605B1Rotation angle control device, automatic clearance adjusting arm, and vehicle brake
Publication Date: 2024.02.28 BPW (MEIZHO) AXLE CO LTD
  • EP3848605B1 patent drawingFigure 1~2
  • EP3848605B1 patent drawingFigure 3~4
  • EP3848605B1 patent drawingFigure 5~6

AI summary

A rotation angle control device comprises: a mandrel (12); a transmission gear (13) sleeved on the mandrel (12); a clutch sleeve (15) sleeved on the mandrel (12) and having a first axial counterbore (141) in an end surface located on one side of the clutch sleeve (15) away from the transmission gear (13); a second worm (18) sleeved on the mandrel (12) and having a second axial counterbore (161) in an end surface located on one side of the second worm (18) adjacent to the transmission gear (13); and an expansion spring (16) sleeved over the mandrel (12) and having an outer circular surface in interfere fit with inner hole surfaces of the first axial counterbore (141) and the second axial counterbore (161) . It also related to an automatic clearance adjuster including a rotation angle control device and an automobile brake including the automatic clearance adjuster.