Torque Clutch Line Contact Reduces Wear and Vibration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional hand-held power tools with torque clutches face issues of increased friction and wear, vibration, and weight due to point contact in torque couplings, which affect reliability and service life.

Innovation Solution

The design incorporates a transmission element with recesses for latching bodies, providing line contact instead of point contact, and a spring element with adjustable force, ensuring reliable positioning and reduced weight, thereby minimizing vibration and enhancing service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If point contact is used in torque coupling, then the structure is simple, but friction and wear increase

Engineering Contradiction:
Improvestructure simplicityVSAvoidfriction and wear
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent transitions from point contact (0D) to line contact (1D) by designing the transmission element with a curved contact surface that engages with the detent element along a line rather than at a single point. This dimensional change increases the contact area, distributing forces more evenly and reducing friction and wear while maintaining structural simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If conventional torque coupling is used, then the design is compact, but vibration increases due to weight

Engineering Contradiction:
Improvecoupling compactnessVSAvoidvibration
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent changes the contact geometry parameter from point to line contact, which fundamentally alters the force distribution and dynamic characteristics of the coupling. This parameter change reduces vibration by distributing contact forces along a line, thereby reducing impact and oscillation while maintaining a compact design.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If point contact is used in torque coupling, then the axial length is reduced, but service life decreases due to wear

Engineering Contradiction:
Improveaxial lengthVSAvoidservice life
Core Design Contradiction:
Length of moving objectVSDuration of action of stationary object

Solution Approach 1:

The patent extends the contact interaction from a point (0D) to a line (1D) by designing the transmission element with a curved surface that contacts the detent element along a line. This line contact maintains a compact axial length while significantly increasing service life by distributing wear along the entire contact line rather than concentrating it at a single point.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design reduces friction and wear, decreases vibration, and extends the service life of the hand-held power tool by ensuring reliable guidance of the transmission element and harmonizing clutch forces.

Implementation Method 1

a transmission element which is acted upon axially by at least one spring element, in particular in the direction of the motor

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3426442B1Hand-held power tool comprising a torque clutch
Publication Date: 2020.06.24 ROBERT BOSCH GMBH
  • EP3426442B1 patent drawingFigure 1
  • EP3426442B1 patent drawingFigure 2
  • EP3426442B1 patent drawingFigure 3

AI summary

Disclosed is a hand-held power tool comprising a transmission and a torque clutch (160) that includes a limiting unit (230) which is associated with the transmission and to which a transmission element (240) is associated that is acted on by a spring element (232; 233); a torque level of the torque clutch (160) can be adjusted via a user-actuated control element (165) at least within predefined limits; according to the invention, the limiting unit (230) includes at least one locking member (250, 251) that engages the transmission element (240) at least in some sections in the axial direction of the torque clutch (160).