Automobile Seat Rotation Assembly With Semicircular Rack End Stops

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Solution Overview

Problem

Existing electric rotation mechanisms for automobile seats have complex structures, large space occupation, non-modularity, high production costs due to heavy machined parts, and low release force, limiting their applicability and mass production.

Innovation Solution

The electric rotation device features a semicircular rack fixed to the rotary support by rivets and welding, with special-shaped teeth to prevent gear disengagement, a reduction gearbox for increased strength and reduced costs, and a driving motor assembly with a spline shaft and smooth shaft for precise positioning and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a semicircular arcuate groove is provided on the rotary support to control rotation angle, then the rotation angle is controlled in a range of 0-180°, but processing costs increase and strength of the rotary support reduces

Engineering Contradiction:
Improverotation angle controlVSAvoidstrength of the rotary support
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent extracts the rotation angle control function from the rotary support by providing the semicircular arcuate groove on the fixed disc instead. The groove engages with a protrusion on the rotary support, achieving the same 0-180° rotation control while preserving the structural integrity and strength of the rotary support itself.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If a fixing block is mounted to the fixed disc to engage with the semicircular arcuate groove, then rotation angle is controlled, but weight and costs increase

Engineering Contradiction:
Improverotation angle controlVSAvoidweight of the fixed disc assembly
Core Design Contradiction:
Ease of operationVSWeight of stationary object

Solution Approach 1:

The patent merges the fixing block function directly into the fixed disc structure. The semicircular arcuate groove is provided directly on the fixed disc, eliminating the need for a separate fixing block component. This integration reduces the overall weight while maintaining the rotation angle control function through engagement with the protrusion on the rotary support.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If heavy machined parts are used in the rotation mechanism, then strength and durability are improved, but mass production becomes difficult and costs increase

Engineering Contradiction:
Improvestrength of rotation mechanismVSAvoidmass production capability
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent changes the manufacturing parameters from heavy machining to light stamping and forming processes. The rotary support, fixed disc, and other components are made through stamping and forming operations that are suitable for mass production, while still achieving the required strength through optimized material selection and structural design.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adopts cost-effective stamping parts instead of expensive machined components. The design uses standardized stamping processes that can be rapidly reproduced for mass production, reducing both manufacturing costs and production time while maintaining adequate strength for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution enables efficient 0-180° reciprocating rotation with increased strength, reduced costs, and prevention of wire harness breakage, while maintaining a compact design and enhanced release force.

Implementation Method 1

an upper ball assembly (500) and a lower ball assembly (600) which enable the rotary disc to perform relative rotation about a vertical axis with respect to the fixed disc

Methodology Applied
Scientific EffectBall bearing: Ball

Implementation Method 2

a driving gear (720) meshed with the semicircular rack (800), wherein the driving gear (720) in the driving motor assembly (700) drives, by using the semicircular rack (800), the rotary support (100) to perform reciprocating rotation

Methodology Applied
Scientific EffectGear meshing: Gear

Data Source

PatentEP3925823B1Electric rotating device for automobile seat
Publication Date: 2024.01.17 YANFENG ADIENT SEATING CO LTD
  • EP3925823B1 patent drawingFigure 1~2
  • EP3925823B1 patent drawingFigure 3
  • EP3925823B1 patent drawingFigure 4

AI summary

An electric rotation device for an automobile seat disclosed in the present invention includes a rotary support, a rotary disc, a fixed disc, a platen, an upper ball assembly, a lower ball assembly, a driving motor assembly, and a semicircular rack. A center of the semicircular rack coincides with a center of rotation of the rotary support. The semicircular rack is meshed with the driving gear. The driving gear in the driving motor assembly is configured to drive, by using the semicircular rack, the rotary support to perform reciprocating rotation in a range of 0-180°. A special-shaped tooth configured to prevent the driving gear from rotating out of the semicircular rack is disposed at each of extreme positions on two ends of teeth in the semicircular rack, so that the driving gear is gradually snapped with the special-shaped teeth to stop further rotation when rotating to the extreme positions on the two ends of the semicircular rack. The present invention has advantages such as an increased strength, reduced costs, and elimination of a gap between extreme positions. In addition, a wire harness of a seat is prevented from being broken as a result of unlimited rotation.