Reverse-Input-Blocking Clutch With Integrated Engagement Element

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Solution Overview

Problem

The existing reverse input blocking clutch designs, such as those described in WO 2021/054481, have a large number of parts, leading to increased manufacturing costs and complexity due to the configuration of the engagement element body and link member.

Innovation Solution

A reverse input blocking clutch with a reduced number of parts, featuring a pressed member, an input member, an output member, and an engagement element with partially cylindrical convex curved surfaces, allowing for smooth switching between locked and unlocked states while reducing manufacturing costs by eliminating the need for a link member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engagement element is configured to include the engagement element body and the link member, then the reverse input blocking clutch can transmit torque and block reverse torque, but the number of parts increases leading to increased manufacturing costs and parts management complexity

Engineering Contradiction:
Improvetorque transmission and blocking functionVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the engagement element body and link member into a single integrated engagement element. The engagement element includes a pressing surface that directly contacts the pressed surface, eliminating the need for a separate link member. This integration maintains the torque transmission and blocking functions while reducing the total number of parts, thereby lowering manufacturing costs and simplifying parts management.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the engagement element is configured to include the engagement element body and the link member, then the reverse input blocking clutch can transmit torque and block reverse torque, but manufacturing costs increase due to more parts

Engineering Contradiction:
Improvetorque transmission and blocking functionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple components (engagement element body and link member) into a single integrated engagement element. This reduction in part count directly lowers manufacturing costs by reducing material requirements, assembly operations, quality control steps, and inventory management expenses, while preserving the essential torque transmission and blocking functions.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the pressing surface is pressed against the pressed surface to block reverse torque, then reverse torque is blocked, but switching to the unlocked state requires smooth separation of the pressing surface from the pressed surface

Engineering Contradiction:
Improvereverse torque blockingVSAvoidswitching smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs curved surfaces (pressing surface and pressed surface) instead of flat surfaces. The curvature allows for gradual contact and separation during switching operations, enabling smooth transitions between locked and unlocked states. The curved geometry distributes contact forces and reduces impact during engagement and disengagement, improving operational smoothness while maintaining reliable reverse torque blocking.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design enables efficient torque transmission and blocking, while reducing manufacturing costs and part management complexity, allowing for stable and smooth switching between locked and unlocked states without increasing the maximum output torque requirements.

Implementation Method 1

the engagement element is configured to press the pressing surface against the pressed surface so that the pressing surface frictionally engages with the pressed surface

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4239210B1Reverse-input-blocking clutch
Publication Date: 2024.11.13 NSK LTD
  • EP4239210B1 patent drawingFigure 1
  • EP4239210B1 patent drawingFigure 2
  • EP4239210B1 patent drawingFigure 3

AI summary

A distance (D1) between a rotation center (O) of an input member (3) and a contact portion (Pin) between an input side engaging portion (9) and an input side engaged portion (17) in a second direction is set to be shorter than a distance (D2) between a rotation center (O) of an output member (4) and a contact portion (Pout) between an output side engaging portion (12) and an output side engaged portion (14) in the second direction in a state in which a pair of pressing surfaces (13) is pressed against a pressed surface (6) in accordance with a rotation of the output member (4) in a predetermined direction and the input side engaging portion (9) engages with the input side engaged portion (17) in accordance with a rotation of the input member (3) in a direction opposite to the predetermined direction. In a locked or semi-locked state, a contact portion (C1) between the output side engaging portion (12) and the output side engaged portion (14) is located on the side closer to the rotation center (O) of the output member (4) in a first direction in relation to a virtual line (L) connecting the rotation center (O) of the output member (4) and a contact portion (C2) between one pressing surface (13) of the pair of pressing surfaces (13) and the pressed surface (6).