Integrated Reverse Input Cut-Off Clutch for Smooth Lock Switching

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Solution Overview

Problem

The existing reverse input cut-off clutch designs, such as those described in PCT International Publication No. WO 2021/054481, have a complex constitution with many parts, leading to high production costs and management complexities.

Innovation Solution

A reverse input cut-off clutch design that includes a pressed member, an input member, an output member, and an engaging element with a pair of pressing surfaces and input/output-side engaged parts, allowing for smooth switching between locked and unlocked states while minimizing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engaging element has an engaging element main body and a link member, then the reverse input cut-off clutch can transmit torque and cut off reverse torque, but the number of parts increases leading to high production costs and management complexities

Engineering Contradiction:

Improvetorque transmission and reverse torque cut-off functionalityVSAvoidnumber of parts

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the engaging element main body and link member into a single integrated engaging element. This engaging element has a body portion that engages with the input member and a link portion that engages with the output member, eliminating the need for separate link members while maintaining the torque transmission and reverse torque cut-off functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The engaging element serves multiple functions: it transmits torque from the input member to the output member, cuts off reverse torque, and provides structural support. By making the engaging element multi-functional, the patent reduces the number of parts needed while maintaining reliable operation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the engaging element has an engaging element main body and a link member, then the reverse input cut-off clutch can transmit torque and cut off reverse torque, but production costs and assembly costs become high

Engineering Contradiction:

Improvetorque transmission and reverse torque cut-off functionalityVSAvoidproduction cost and assembly cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent integrates the functions of the engaging element main body and link member into a single component, reducing the number of parts that need to be manufactured and assembled. This integration directly reduces production costs and assembly costs while maintaining the required functionality.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the pressing surface is frictionally engaged with the pressed surface, then reverse torque is cut off, but switching between locked and unlocked states requires smooth displacement of the engaging element

Engineering Contradiction:

Improvereverse torque cut-offVSAvoidswitching between locked and unlocked states

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The engaging element is designed to dynamically displace between engaged and disengaged positions. When torque is applied to the input member, the engaging element smoothly displaces to engage with the output member, enabling transition between locked and unlocked states while maintaining reliable reverse torque cut-off through frictional engagement.

Inventive Principle:

Principle #15Dynamics

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 proposed design enables smooth switching between locked and unlocked states, reducing production costs and simplifying part management, while maintaining effective torque transmission and reverse input cut-off functionality.

Implementation Method 1

the pressing surface is frictionally engaged with the pressed surface by pressing the pressing surface against the pressed surface

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP4276325B1Reverse input cut-off clutch

Publication Date: 2025.01.15 NSK LTD

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AI summary

In a predetermined first state, a distance (D1) in a second direction between a contact portion (Pin) between a input-side engaging part (9) and an input-side engaging part (17) and a rotation center (O) is larger than a distance (D2) in the second direction between a contact portion (Pout) between an output-side engaging part (12) and an output-side engaged part (14) and the rotation center (O). In a locked state or a semi-locked state, a contact portion (C1) between the output-side engaging part (12) and the output-side engaged part (14) is located closer to the rotation center (O) of the output member (4) in a first direction than an imaginary straight line (L) connecting a contact portion (C2) between one pressing surface (13) of the pair of pressing surfaces (13) and a pressed surface (6) to the rotation center (O) of the output member (4).