Clutch Outer Ring Structure for Locked Seat Load Protection

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Solution Overview

Problem

In a state where a vehicle seat is fully raised or fully lowered, operating the output-side clutch can lead to excessive loads that may cause breakage or deformation of components.

Innovation Solution

A clutch unit design featuring an input-side outer ring member with a thick part projecting outward in the radial direction, enhancing radial strength, and a wedge-shaped space configuration to prevent excessive loads from deforming components when the output-side clutch is locked.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the operation lever is operated when the output-side clutch is locked (fully raised or lowered position), then the seat operation can be performed, but excessive load is applied that may break or deform components

Engineering Contradiction:
Improveseat operationVSAvoidcomponent strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies beforehand cushioning by designing a deformation-absorbing structure in the input-side outer ring member. The thick part of the outer ring member is intentionally designed to deform elastically under excessive load conditions, absorbing the shock and preventing breakage of critical components. This cushioning mechanism is built into the structure in advance to handle abnormal operating conditions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies parameter changes by varying the thickness of the input-side outer ring member. The thick part has a greater thickness than other parts, creating a gradient structure that allows controlled deformation. This parameter change enables the component to withstand excessive loads by deforming in a controlled manner rather than breaking.

Inventive Principle:
Principle #35Parameter changes

2Strength

If a thick part is added to the input-side outer ring member to prevent breakage, then component strength is improved, but device complexity increases

Engineering Contradiction:
Improvecomponent strengthVSAvoidclutch unit structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies local quality by making only a specific portion (the thick part) of the input-side outer ring member thicker, rather than increasing the thickness of the entire component. This localized modification provides the necessary strength and deformation capability only where needed, while keeping the rest of the structure simple and lightweight.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies segmentation by dividing the outer ring member into different thickness zones - a thick part for deformation absorption and thinner parts for other functions. This segmentation allows each zone to serve its specific purpose optimally while maintaining overall structural efficiency.

Inventive Principle:
Principle #1Segmentation

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 effectively prevents breakage and deformation of components by distributing and reducing excessive loads, ensuring the clutch unit's durability even under locked conditions.

Implementation Method 1

an input-side transmission member disposed in a wedge-shaped space formed between an outer peripheral surface of the input-side inner ring member and an inner peripheral surface of the input-side outer ring member

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a thickness of the thick part in the radial direction is larger than a thickness of a non-thick part in the radial direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4148294B1Clutch unit
Publication Date: 2025.11.26 NTN CORP
  • EP4148294B1 patent drawingFigure 1
  • EP4148294B1 patent drawingFigure 2
  • EP4148294B1 patent drawingFigure 3~4

AI summary

A clutch unit (100) includes an operation lever, an operation bracket (54), an output shaft member (30), an input-side clutch, an output-side clutch, and a housing (11). An input-side outer ring member (52) of the input-side clutch is a member including a bottom part (52b) and an outer ring part (52c). Apart of the outer ring part (52c) is a thick part (52e). The thickness of the thick part (52e) in the radial direction is larger than the thickness of a non-thick part (52f) in the radial direction.