Sliding Bearing Conical Surface Eliminates Radial Backlash

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Solution Overview

Problem

The existing sliding bearings for strut-type suspensions in automobiles experience radial backlash due to clearance between the radial load transmission surface of the upper case and the radial bearing surface of the center plate, leading to discomfort during steering operations.

Innovation Solution

The sliding bearing features conical surface shapes on the bearing surface of the annular center plate and the load transmission surface of the lower case, allowing both thrust and radial loads to be supported by the same bearing surface, thereby eliminating radial clearance and backlash.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dimension tolerance is set for the upper case, lower case, and center plate to ensure they can be surely combined, then assembly reliability is improved, but radial clearance is generated between the radial load transmission surface and radial bearing surface, causing backlash

Engineering Contradiction:
Improveassembly reliabilityVSAvoidsteering smoothness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention applies conical surfaces (curved surfaces) to the bearing surface of the center plate and the load transmission surface of the lower case. This curvature design allows the surfaces to contact each other along a line or area rather than at discrete points, eliminating radial clearance and backlash while maintaining assembly reliability through dimensional tolerances.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If separate bearing surfaces are used for thrust loads and radial loads, then load support functionality is improved, but structural complexity increases

Engineering Contradiction:
Improveload support functionalityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention makes the conical bearing surface of the center plate and the conical load transmission surface of the lower case serve dual functions: supporting both thrust loads (axial direction) and radial loads (radial direction). The same contact surfaces handle both load types simultaneously, eliminating the need for separate bearing surfaces and reducing structural complexity.

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

Solution Approach 2:

The invention merges the thrust bearing function and radial bearing function into a single integrated conical contact interface between the center plate and lower case. By combining these functions into one structural element, the design simplifies the overall structure while maintaining the ability to support both types of loads effectively.

Inventive Principle:
Principle #5Merging (Combining)

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 design prevents radial backlash by ensuring continuous contact between the bearing and load transmission surfaces, enhancing the smooth operation and stability of the sliding bearing during steering.

Implementation Method 1

a bearing surface of an annular center plate (4), and a load transmission surface (27) which is formed in a lower case (3) for sliding on the bearing surface (42) of the center plate (4)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3290726B1Sliding bearing
Publication Date: 2021.01.27 OILES CORP
  • EP3290726B1 patent drawingFigure 1(A)~1(D)
  • EP3290726B1 patent drawingFigure 2(A)~2(B)
  • EP3290726B1 patent drawingFigure 3(A)~3(D)

AI summary

Provided is a sliding bearing wherein radial play is prevented. A sliding bearing (1) comprises: an upper case (2) mounted to an upper support for mounting the strut assembly of a strut-type suspension to a vehicle body; a lower case (3) which is mounted to an upper spring seat for supporting the upper end of the coil spring of the strut-type suspension, is combined with the upper case (2) so that the upper case (2) and the lower case (3) can pivot relative to each other, and forms an annular space (5) between the upper case (2) and the lower case (3) ; and an annular center plate (4) disposed in the annular space (5) and enabling the upper case (2) and the lower case (3) to pivot relative to each other. The center plate (4) has a circular conical surface-shaped bearing surface (41). The upper case (2) has a circular conical surface-shaped load transmission surface (27) sliding on the bearing surface (42) of the center plate (4).