Suspension Strut Bearing Cup Assembly for Sealing and Axial Demolding

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Solution Overview

Problem

The existing suspension stop designs for motor vehicles, particularly those involving a telescopic suspension strut, face manufacturing complexities due to the need for intricate features like radial cavities and annular grooves, which complicate the molding process and hinder axial demolding, especially when using thermoplastic materials, and also struggle to achieve a balance between sealing and torque performance.

Innovation Solution

A suspension stop design featuring an upper cup with an annular base and a lower cup forming an interface with a radial hook in a groove, where the groove has an axial bottom with lugs and recesses that axially retain the cups, allowing for easier manufacturing and assembly, while an annular sealing element with a conical side wall provides effective sealing and torque management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a radial cavity is formed in the crown to engage hooks, then the cohesion of the suspension stop components is improved, but the manufacturing complexity increases and axial demolding is prevented

Engineering Contradiction:
Improvecohesion of suspension stop componentsVSAvoidmolding process complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Instead of forming hooks in the crown (lower cup), the invention inverts the approach by forming lugs in the base (upper cup) that engage with recesses in the sleeve (lower cup). This inversion allows axial demolding while maintaining the cohesion function, as the lugs and recesses can be formed during molding without preventing demolding.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention transitions from a radial engagement mechanism (hooks in radial cavities) to an axial engagement mechanism (lugs in recesses). The lugs project axially from the base and engage with recesses in the sleeve, changing the dimension of engagement from radial to axial, which facilitates demolding while maintaining component cohesion.

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

2Reliability

If an annular groove is formed in the crown to mount the sealing ring, then the sealing function is improved, but the manufacturing complexity increases and axial demolding is prevented

Engineering Contradiction:
Improvesealing functionVSAvoidmolding process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts the sealing groove from the crown (lower cup) and relocates it to the base (upper cup). The groove is now formed in the base to receive the sealing ring, which simplifies the molding process by allowing axial demolding of the lower cup while maintaining the sealing function through the repositioned groove in the base.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the sealing ring is made movable in the annular groove to ensure good sealing, then the tightness is improved, but the torque induced by the sealing function increases

Engineering Contradiction:
ImprovetightnessVSAvoidinduced torque
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention changes the geometric parameters of the sealing groove, giving it a trapezoidal cross-section with a larger base angle (α) than the sealing ring's contact angle (β). This parameter change allows the sealing ring to be tightly retained in the groove while reducing the frictional torque, as the wider base provides better retention without requiring excessive radial pressure from the sealing ring.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4261059A1Vehicule suspension strut bearing
Publication Date: 2023.10.18 NTN EUROPE
  • EP4261059A1 patent drawingFigure 1~1a
  • EP4261059A1 patent drawingFigure 2~3
  • EP4261059A1 patent drawingFigure 4~6

AI summary

The invention relates to a suspension bump stop for a motor vehicle in which the upper cup (1) comprises an annular base (14) surrounded by a sleeve (11) of the lower cup (2) forming an interface (15) for assembling said cups which has a radial hook (18) originating from the sleeve (11) disposed in a groove (19) of the base (14), said groove having an axial bottom surrounded by two edges respectively upper and lower which are arranged to axially retain the cups (1, 2), the lower edge having lugs (23) formed projecting over a radial length to interact axially with the hook (18), each of said lugs having an angular width which is surmounted by a recess opening into a hollow formed in the upper edge, each of said hollows being disposed axially opposite a lug (23) having a radial depth which is at least equal to the radial length of said lugs.