Piezoelectric Actuator Cable Pull System for Electric Bicycle ABS

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Anti-lock braking systems (ABS) have not been widely adopted in electric bicycles due to cost constraints, making them unsuitable for mass use, despite the safety benefits of equipping two-wheelers with such systems.

Innovation Solution

A cost-effective and robust cable pull system incorporating a length-change element with a piezoelectric actuator, which allows for length adjustment through a deflection mechanism, enabling integration into ABS systems and providing a simple and space-saving design for electric bicycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ABS braking systems are equipped in electric bicycles, then safety is improved, but cost increases

Engineering Contradiction:
ImprovesafetyVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces complex mechanical ABS components with a piezoelectric actuator that uses electrical fields to control cable tension. This substitution reduces mechanical complexity and manufacturing costs while maintaining safety functionality, directly addressing the contradiction between safety improvement and cost increase

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

Solution Approach 2:

The invention changes the operating parameters by using electrical voltage control instead of traditional mechanical linkages. The piezoelectric actuator responds to electrical signals to adjust cable tension dynamically, enabling cost-effective ABS implementation through electrical parameter control rather than complex mechanical systems

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a piezoelectric actuator is used for length adjustment, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvedevice complexityVSAvoidmanufacturing precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The connecting arm is designed with inherent elastic properties that enable automatic resetting to the neutral position after deflection. This self-service mechanism eliminates the need for additional restoring elements or complex control systems, reducing device complexity while the elastic material properties provide self-compensation for manufacturing tolerances

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention utilizes the elastic parameters of the connecting arm material to achieve automatic resetting. By selecting materials with appropriate elastic properties, the system compensates for manufacturing precision variations through material behavior rather than requiring extremely tight manufacturing tolerances

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the connection area is arranged in the middle of the first connecting arm, then loading uniformity is improved, but structural compactness decreases

Engineering Contradiction:
Improveloading uniformityVSAvoidstructural compactness
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The patent employs an asymmetric arrangement where the connection area is positioned in the middle of the first connecting arm while the piezoelectric actuator is positioned eccentrically. This asymmetric configuration achieves uniform loading distribution through the central connection point while the overall structure remains compact due to the space-efficient positioning of components

Inventive Principle:
Principle #4Asymmetry

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 a compact, cost-effective implementation of ABS in electric bicycles, enhancing safety by allowing precise control of braking forces and reducing the risk of wheel blockage, while maintaining a minimal impact on the vehicle's range due to low power consumption.

Implementation Method 1

The length change element (20) comprises a piezoelectric actuator (23) with an actuator foot (24) and an actuator head (25). The piezoelectric actuator is configured to change its length in response to an applied voltage.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The first connection space is made from a material with inherent elasticity, for example spring steel or plastic. After the length-changing element has been deflected by the piezoelectric actuator, the length-changing element is automatically reset to a starting position.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3078557B1Length changing element having piezoelectric actuator and vehicle with abs braking system
Publication Date: 2021.08.11 ROBERT BOSCH GMBH
  • EP3078557B1 patent drawingFigure 1
  • EP3078557B1 patent drawingFigure 2~3
  • EP3078557B1 patent drawingFigure 4

AI summary

The invention relates to a length-changing element (20) comprising a piezo actuator (23) with an actuator base (24) and an actuator head (25), a first end region (21) and a second end region (22), wherein the first end region (21) is connected to the actuator head (25) and the second end region (22) is connected to the actuator base (24), and at least one first connecting arm (26) which connects the first end region (21) to the second end region (22).