Reverse-Input Blocking Clutch Housing for Pressed Surface Roundness

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Solution Overview

Problem

The existing reverse-input blocking clutches suffer from deterioration of roundness in the pressed surface due to direct connection and fixation to a non-rotating motor housing, leading to inconsistent switching times and reduced controllability and locking performance.

Innovation Solution

The reverse-input blocking clutch design includes a housing configuration that separates the input-side and output-side housing elements, preventing deformation of the pressed surface by avoiding direct bolting, and employs engaging elements with elastic members and reinforcing structures to ensure precise coaxiality and smooth transitions between locked, semi-locked, and unlocked states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the clutch housing is directly connected and fixed to the motor housing by bolts, then the structure is simplified and manufacturing cost is reduced, but the roundness of the pressed surface deteriorates due to deformation

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidroundness of pressed surface
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The clutch housing is divided into two separate elements: an input-side housing element that rotates with the input member and an output-side housing element that is fixed to the motor housing. This segmentation prevents the pressed surface from being deformed by bolting, as the input-side housing element is not directly bolted to the motor housing, thereby maintaining the roundness of the pressed surface while still allowing for a relatively simple manufacturing process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The input-side housing element acts as an intermediary between the motor housing and the pressed surface. Instead of directly bolting the clutch housing to the motor housing, the input-side housing element is coupled to the motor housing through the engaging elements and output-side housing element, which mediates the connection and prevents direct transmission of bolting forces to the pressed surface, thus preserving its roundness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the pressing surfaces of engaging elements are pressed against the pressed surface, then reverse-input blocking is achieved, but the switching time becomes inconsistent due to phase variation

Engineering Contradiction:
Improvereverse-input blocking functionVSAvoidswitching time consistency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

By segmenting the clutch housing into input-side and output-side elements, the rotation of the input-side housing element is decoupled from the fixed output-side housing element. This ensures that the pressed surface on the output-side housing element remains stationary and maintains consistent geometric relationships with the engaging elements, leading to consistent switching times while still achieving reliable reverse-input blocking when the pressing surfaces contact the pressed surface.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the engaging elements are held strongly between the output-side engaging portion and pressed surface, then locking performance is improved, but the roundness of pressed surface deteriorates due to deformation

Engineering Contradiction:
Improvelocking performanceVSAvoidroundness of pressed surface
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The segmentation of the clutch housing into input-side and output-side elements isolates the pressed surface on the output-side housing element from deformation forces. When engaging elements are pressed against this isolated pressed surface to achieve strong locking, the reaction forces are transmitted to the fixed motor housing through the output-side housing element rather than deforming the pressed surface, thus maintaining both locking performance and roundness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The output-side housing element serves as a rigid, deformation-free copy or reference frame for the pressed surface. By fixing this element to the motor housing and using it as the mounting surface for the pressed surface, the system creates a stable, non-deforming reference that maintains its geometric integrity even under high locking forces, effectively copying the ideal rigid body behavior needed for consistent locking performance.

Inventive Principle:
Principle #26Copying

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 maintains the roundness of the pressed surface, enhances controllability, and ensures consistent switching performance, reducing manufacturing costs and preventing positional deviations in mechanical systems.

Implementation Method 1

Each engaging element 5 has a pressing surface 39... The reverse-input blocking clutch 1 includes a pair of elastic members 50... elastically held between the output-side engaging portion 13 and the engaging element 5 so as to press the engaging element 5 toward the pressed surface 24

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

When a rotational torque is reversely input to the second shaft 104 and the output portion 110 rotates... the pressing surfaces 123 of the engaging elements 111 are pressed against the pressed surface 118 of the clutch housing 108. As a result, the rotational torque reversely input to the second shaft 104 is completely blocked by being transmitted to the clutch housing 108

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4265934B1Reverse-input-blocking clutch
Publication Date: 2025.07.09 NSK LTD
  • EP4265934B1 patent drawingFigure 1
  • EP4265934B1 patent drawingFigure 2
  • EP4265934B1 patent drawingFigure 3

AI summary

A pressed member 4 includes a first pressed member element 16 having a pressed surface 24 around an inner peripheral surface thereof and a second pressed member element 17 having a mounting portion 64 fixed to a portion 62 that does not rotate during use.