Over-running clutch with angled contact plane

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Solution Overview

Problem

Existing over-running clutches experience excessive wear due to excessive friction between coupling parts, which is not adequately addressed in current designs.

Innovation Solution

The clutch design features a flattened portion on the shaft that presses coupling members into a cylindrical drive portion when rotated, allowing them to disengage and rotate freely when the motor is off, with a contact plane angle of 4-10° to facilitate easy release from the drive portion's hollows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If coupling members are pressed against the drive portion to transmit torque, then torque transmission capability is improved, but friction and wear between parts increase

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidwear of coupling parts
Core Design Contradiction:
PowerVSLoss of substance

Solution Approach 1:

The contact plane of the disk is designed with a specific angle (4-10 degrees) relative to the contact surface of the coupling member. This angular parameter change allows the coupling members to be pressed outward by the flattened shaft portion during rotation, enabling them to easily turn over and disengage from the hollows of the drive portion, thereby reducing friction and wear while maintaining torque transmission capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coupling members are designed to dynamically transition between engaged and disengaged states. During motor operation, they are pressed into the hollows for torque transmission; when the motor stops, they automatically turn over and disengage due to the angled contact plane, minimizing continuous friction and wear

Inventive Principle:
Principle #15Dynamics

2Strength

If coupling members are pressed firmly against the drive portion, then coupling strength is improved, but friction during operation increases

Engineering Contradiction:
Improvecoupling strengthVSAvoidfriction during operation
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The angled contact plane (4-10 degrees) creates a mechanical advantage that allows strong pressing force during engagement while facilitating easy release. The angle optimizes the balance between maintaining strong coupling during operation and enabling low-friction disengagement, reducing harmful friction effects

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the contact plane is perpendicular to the shaft centerline, then coupling stability is improved, but release from hollows becomes difficult

Engineering Contradiction:
Improvecoupling stabilityVSAvoidrelease from hollows
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The contact plane is deliberately designed asymmetrically with respect to the shaft centerline, forming an angle of 4-10 degrees. This asymmetric geometry provides stability during engagement while creating a natural release mechanism that facilitates easy turnover and disengagement from the hollows when the motor stops

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The specific angular parameter (4-10 degrees) of the contact plane optimizes the balance between stability and ease of release. This parameter change ensures that the coupling members remain stable during torque transmission but can easily turn over and disengage when the driving force is removed

Inventive Principle:
Principle #35Parameter changes

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 wear by allowing the coupling members to easily turn over and disengage from the drive portion, minimizing friction and wear when the shaft is stopped, thus extending the clutch's lifespan.

Implementation Method 1

two contact surfaces 11 are shaped... said coupling element 12 is provided with a cam 14, which can extend itself through said sleeve 9... said coupling members will be pressed outwardly by said flattened portion of said shaft when this is rotated

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

at least a part of the contact plane of a disk, directed to a coupling member, is making an angle between 4 and 10° with the contact surface of said coupling member extending square to the ceterline of said shaft, such that said contact surface in the direction of the centerline of said shaft is at increasing distance of the contact surface of said coupling member

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2852772B1Over-running clutch
Publication Date: 2017.07.12 FOREST GROUP NEDERLAND
  • EP2852772B1 patent drawingFigure 1~4

AI summary

Over-running clutch (4) serving for coupling a motoric driven shaft (3) to a driven element (6), in which said element (6) can freely rotate when the motor (1) is switched off. The driven shaft (3) of said clutch (4) is provided with a flattened portion (10) with two flat walls (11), in which a wall (13) of a coupling member (12) engages one of said walls (11) when said driven shaft (3) stands still, said coupling member (12) being provided with an outwardly extending cam (14), being received in a sleeve (9) of a cylindrical collar (8) positioned on a disk (9) being rotatable mounted on said driven shaft (3), such that said coupling member (12), when said shaft (3) is rotated, can be pressed outward over a limited distance and the cam (14) can be received in a hollow (15) provided in the inner wall (16) of a cylindrical drive portion (17) forming part of said driven element (6).