Eccentric Wobble Gear Adjustment Fitting for Vehicle Seats

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Solution Overview

Problem

Existing adjustment fittings for vehicle seats face issues with secure axial cohesion and ease of installation, leading to unwanted rattling noises or high friction during adjustment, which affects comfort and usability.

Innovation Solution

The design incorporates a ring gear with a base and extended outer wall that securely holds the inner wheel via a radially inward collar, allowing for easy installation and adjustment of axial play through a holding element, which can be fixed using welding or gluing, and utilizes cold extrusion for strength-optimized production of the wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the axial play between the fitting parts is reduced to eliminate rattling noises, then the reliability and comfort are improved, but the frictional force increases making adjustment difficult

Engineering Contradiction:
Improveaxial cohesionVSAvoidadjustment effort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention changes the geometric parameters of the wheel components by providing an extended inner wall on the inner wheel that protrudes axially beyond the external toothing, and an extended outer wall on the outer wheel that engages with a collar. This geometric modification allows the walls to bear against each other axially, providing cohesion without requiring excessive preloading that would increase friction during adjustment operations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the fitting parts are securely held together axially, then the rattling noises are eliminated, but the installation complexity increases

Engineering Contradiction:
Improveaxial cohesionVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the axial cohesion function into the wheel components themselves by extending the inner and outer walls axially beyond the toothing. These extended walls directly bear against each other to provide axial securing, eliminating the need for separate retaining rings, locking mechanisms, or additional fastening components that would increase assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts the axial cohesion function from separate fastening components and integrates it directly into the wheel structure through the extended inner and outer walls. This allows the wheels to self-secure axially through their own structural features without requiring additional dedicated fastening elements.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the inner wheel is made accessible from the outside for adapter connection, then the adaptability is improved, but the structural complexity increases

Engineering Contradiction:
Improveadapter connectionVSAvoidwheel structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The extended inner wall on the inner wheel serves multiple functions: it provides axial bearing surface for securing the inner wheel to the outer wheel, and simultaneously creates an accessible outer surface for connecting adapters to the inner wheel. This multi-functional design achieves adaptability without requiring separate adapter mounting structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution provides secure axial cohesion, reduces friction, and facilitates easy installation and adjustment, enhancing the comfort and usability of vehicle seat adjustments while allowing for versatile adaptation to different seat models.

Implementation Method 1

an external toothing in the manner of a wobble gear is inserted eccentrically to the axis of rotation, and the inner wheel forms an eccentric receiving space to the axis of rotation, with an eccentric rotatably inserted into the eccentric receiving space

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Implementation Method 2

The connection of a corresponding adapter can be done, for example, by welding, advantageously by laser welding

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP2300266B1Adjustment fitting
Publication Date: 2016.10.12 BROSE FAHRZEUGTEILE GMBH & CO KG
  • EP2300266B1 patent drawingFigure 1
  • EP2300266B1 patent drawingFigure 2
  • EP2300266B1 patent drawingFigure 3

AI summary

Adjustment fitting (1, 100), in particular for a vehicle seat, comprising a first fitting part (2, 102) and a second fitting part (3, 103) that can be rotationally adjusted relative to the first fitting part (2, 102) about an axis of rotation (A). An external gear (4, 104, 301), which has internal teeth (12, 112, 308) and into which an internal gear (7, 107, 320) that is associated with the second fitting part (3, 103) and has external teeth (16, 116, 323) is inserted eccentrically to the axis of rotation (A) like an eccentric gear, is associated with the first fitting part (2, 102). The internal gear (7, 107, 320) forms an eccentric receiving space (25, 124) towards the axis of rotation (A). The adjustment fitting (1, 100) further comprises an eccentric member (30, 32, 126, 127) that is rotatably inserted into the eccentric receiving space (25, 124), and a drive shaft (134) for driving the eccentric member (30, 32, 126, 127). The external gear (4, 104, 301) is designed as a ring gear (5) that has a bottom (9, 109) and an external wall (10, 110, 304) which axially extends beyond the internal teeth (12, 112, 308) and embraces the external teeth (16, 116, 323) of the internal gear (7, 107, 320) by means of a radially inward-oriented collar (21, 115). In addition, the internal gear (7, 107, 320) comprises an internal wall (18, 116, 321) which axially extends beyond the external teeth (16, 116, 323) and axially penetrates the collar (21, 115). The fitting parts (2, 102, 3, 103) are thus securely fastened in the axial direction while access is made easy, especially for mounting the adjustment fitting on a vehicle seat or a seat adapter.