Vehicle Seat Locking Unit Axial Stop Element Design

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Solution Overview

Problem

Existing vehicle seat locking units are sensitive to angular and positional tolerances between the rotary latch and locking bolt, leading to noise issues and reduced locking strength due to misalignment, which affects the clamping distance and engagement of the pawl.

Innovation Solution

A locking unit design with a stop element that protrudes into the lock housing, reducing the clamping distance by overlapping or containing the contact areas between the locking bolt and the stop element, and the rotary latch, making it less sensitive to angular and positional tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the locking bolt is allowed to pivot due to tolerances, then the locking unit can accommodate positional variations, but the clamping distance increases and locking strength decreases

Engineering Contradiction:
Improveaccommodation of positional variationsVSAvoidlocking strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The stop element is pre-positioned to limit the pivot movement of the locking bolt before it can occur during operation. By establishing the axial constraint in advance through the stop element's fixed position, the design prevents the locking bolt from deviating beyond the overlapping contact areas, thereby maintaining optimal clamping distance and locking strength while still accommodating normal tolerance variations.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the clamping distance is reduced to improve locking strength, then the locking unit becomes less sensitive to tolerances, but the contact areas between components must be precisely positioned

Engineering Contradiction:
Improvelocking strengthVSAvoidpositioning precision of contact areas
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The stop element constrains the locking bolt primarily in the axial dimension, allowing the contact areas between the locking bolt, stop element, and rotary latch to overlap axially. This axial overlapping arrangement reduces the system's sensitivity to angular and positional tolerances while maintaining a reduced clamping distance, as the stop element's axial position defines the constraint rather than requiring precise positioning in multiple dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the rotary latch is tilted to accommodate misalignment, then the locking unit can function with skewed locking bolts, but noise increases due to contact with the housing

Engineering Contradiction:
Improvefunctionality with skewed locking boltsVSAvoidnoise
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The stop element is extracted as a separate functional component from the housing structure, positioned to intercept and constrain the locking bolt's movement before it can cause the rotary latch to tilt and contact the housing. By removing the source of the tilting action through the stop element's constraint, the design eliminates the noise-generating contact between the rotary latch and housing while maintaining adaptability to skewed locking bolts.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3033246B1Locking unit for a vehicle seat and vehicle seat
Publication Date: 2021.02.24 ADIENT LUXEMBOURG HLDG SARL
  • EP3033246B1 patent drawingFigure 1~2
  • EP3033246B1 patent drawingFigure 3~4
  • EP3033246B1 patent drawingFigure 5~6

AI summary

The invention relates to a locking unit (10) for a vehicle seat (1), comprising a lock housing having a receptacle opening (19) for receiving a locking bolt (12) and a rotary latch (20), mounted to be able to swivel around a first bearing bolt (51), which rotary latch (20) has a hook aperture (21) for locking together with a locking bolt (12). The bearing bolt (51) is aligned in an axial direction and the receptacle opening (19) is delimited by a stop element (61). The stop element (61) represents a stop for a locking bolt (12) located in the hook aperture, and the stop element (61) protrudes into the lock housing in the axial direction. When the locking unit (10) is in a locked state and the locking bolt (12) extends precisely in the axial direction, a first contact region (71) between the locking bolt (12) and the stop element (61) and a second contact region (72) between the locking bolt (12) and the rotary latch (20) partially overlap in the axial direction, or the first contact region (71) lies completely within the second contact region (72) in the axial direction. The invention further relates to a vehicle seat (1), comprising at least one such locking unit (10).