SLIDING ELEMENT FOR AN ENGINE

Abstract

A sliding element for an engine may include a metallic substrate, a first polymer-based layer, and a second polymer-based layer. The first polymer-based layer may include a polymeric material and may be disposed on the metallic substrate. The second polymer-based layer may include a polymeric material and may be disposed on the first polymer-based layer. The polymeric material of the first polymer-based layer may be the same as the polymeric material of the second polymer-based layer. The second polymer-based layer may further include a tungsten disulphide particulate.

Claims

1. A sliding element for an engine, comprising: a metallic substrate; a first polymer-based layer including a polymeric material disposed on the metallic substrate; and a second polymer-based layer including a polymeric material disposed on the first polymer-based layer; wherein the polymeric material of the first polymer-based layer is the same as the polymeric material of the second polymer-based layer; and wherein the second polymer-based layer further includes a tungsten disulphide particulate.

2. The sliding element according to claim 1, wherein the polymeric material of the first polymer-based layer and the polymeric material of the second polymer-based layer include polyamide-imide.

3. The sliding element according to claim 1, wherein the second polymer-based layer is composed of 70 wt % tungsten disulphide particulate or less.

4. The sliding element according to claim 1, wherein the second polymer-based layer is composed of at least 15 wt % tungsten disulphide particulate.

5. The sliding element according to claim 1, wherein the tungsten disulphide particulate includes a plurality of particles having a length of 10 m or less along a longest dimension.

6. The sliding element according to claim 5, wherein the plurality of particles have a length of 1 m or less along a dimension extending perpendicular to the longest dimension.

7. The sliding element according to claim 1, wherein the second polymer-based layer has a thickness which is less than a thickness of the first polymer-based layer.

8. The sliding element according to claim 1, wherein the second polymer-based layer has a thickness of 6 m or less.

9. The sliding element according to claim 1, wherein the first polymer-based layer has a thickness of 9 m or less.

10. The sliding element according to claim 1, wherein the second polymer-based layer further includes a dispersion additive.

11. The sliding element according to claim 1, wherein the first polymer-based layer further includes an aluminium particulate.

12. An engine comprising a sliding element, the sliding element including: a metallic substrate; a first polymer-based layer including a polymeric material disposed on the metallic substrate; and a second polymer-based layer including a polymeric material disposed on the first polymer-based layer; wherein the polymeric material of the first polymer-based layer is the same as the polymeric material of the second polymer-based layer; and wherein the second polymer-based layer further includes a tungsten disulphide particulate.

13. A method of manufacturing a sliding element for an engine, the method comprising: applying a first polymer-based layer including a polymeric material to a metallic substrate; and applying a second polymer-based layer including a polymeric material to the first polymer-based layer; wherein the polymeric material of the first polymer-based layer is the same as the polymeric material of the second polymer-based layer; and wherein the second polymer-based layer further includes a tungsten disulphide particulate.

14. The method according to claim 13, wherein applying the first polymer-based layer and applying the second polymer-based layer are two distinct application steps.

15. The method according to claim 13, further comprising curing the first polymer-based layer and the second polymer-based layer arc cured.

16. The method according to claim 15, wherein curing the first polymer-based layer and the second polymer-based layer occurs in a single step.

17. The method according to claim 13, further comprising: forming a first mixture via mixing components of the first polymer-based layer with a solvent; and forming a second mixture via mixing components of the second polymer-based layer with a solvent; wherein applying the first polymer-based layer includes disposing the first mixture on the metallic substrate; and wherein applying the second polymer-based layer includes disposing the second mixture on the first polymer-based layer.

18. The sliding element according to claim 1, wherein the first polymer-based layer further includes a fluoropolymer.

19. The sliding element according to claim 1, wherein the first polymer-based layer further includes a silane material.

20. The sliding element according to claim 1, wherein the tungsten disulphide particulate is a plurality of tungsten disulphide flakes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The invention will further be described by way of example only with reference to the accompanying drawing, in which:

[0070] FIGURE shows a perspective view of a sliding element according to preferred embodiments of the present invention.

[0071] The FIGURE provided herein is schematic and not to scale.

DETAILED DESCRIPTION

[0072] FIGURE schematically illustrates a sliding element for an engine in the form of a hollow semi-cylindrical bearing lining shell (commonly referred to as a half bearing) according to a preferred embodiment of the present invention. Many alternative shapes and configurations of the bearing element are envisaged and will be readily apparent to the skilled person.

[0073] The sliding bearing 100 comprises a metallic substrate 102 formed from steel or aluminium. The sliding bearing 100 further comprises a first polymer-based layer 104 provided on the metallic substrate 102. The first polymer-based layer 104 comprises a polymeric material. The sliding bearing 100 further comprises a second polymer-based layer 106 provided on the first polymer-based layer 104. The second polymer-based layer 106 comprises a polymeric material. The polymeric material of the first polymer-based layer 104 is the same as the polymeric material of the second polymer-based layer 106. The modulus of elasticity of the polymeric material of the first polymer-based layer 104 is the same as the modulus of elasticity of the polymeric material of the second polymer-based layer 106. The polymeric material of the first polymer-based layer 104 and the polymeric material of the second polymer-based layer 106 comprises polyamide-imide.

[0074] The second polymer-based layer 106 further comprises tungsten disulphide particulate in the form of tungsten disulphide flakes. The tungsten disulphide particulate comprises particles which have a length of less than 10 m in a longest dimension and less than 1 m in a dimension perpendicular to a longest dimension. The second polymer-based layer 106 comprises between about 20 wt % and about 30 wt % tungsten disulphide particulate. The second polymer-based layer 106 further comprises phosphoric acid ester as a dispersion additive.

[0075] The first polymer-based layer 104 further comprises between about 24 wt % and about 28 wt % aluminium particulate in the form of aluminium flakes, between about 8 wt % and about 12 wt % PTFE as a solid lubricant, and between about 4 wt % and about 6 wt % silane. The remaining wt % of the layer is the polyamide-imide.

[0076] The second polymer-based layer 106 has a thickness of between about 4 m and about 6 m. The first polymer-based layer 104 has a thickness of between about 6 m and about 8 m. The remaining wt % of the layer is the polyamide-imide.

[0077] The sliding element described above may be formed according to the following method. The components of the first polymer-based layer are mixed and combined with a solvent to form a first mixture. The components of the second polymer-based layer are mixed and combined with a solvent to form a second mixture. The first mixture is sprayed onto the surface of the metallic substrate in a series of passes until the desired thickness is reached to form a first polymer-based layer. The formation of the first polymer-based layer may take between about 1 and about 6 passes. The first mixture is dried between each pass but it is not cured. The second mixture is sprayed onto the first polymer-based layer to form a second polymer-based layer. The second polymer mixture is sprayed onto the first polymer-based layer in a series of passes. The formation of the second polymer-based layer may take between about 1 and about 4 passes. The second mixture is dried between each pass but it is not cured. Once the desired thickness of the second polymer-based layer is reached, both the first and second polymer-based layers are cured by heating the sliding element.

[0078] Although illustrated in FIGURE in relation to a half bearing shell, the present invention equally applies to other sliding engine components, including semi-annular, annular or circular thrust washers, and bushes. The mechanical performance enhancing additives (e.g. dry lubricant particulate, silane and metal particulate) dispersed within the polymer-based matrix provide significant enhancements to the mechanical performance of the sliding engine component, such as wear resistance, adhesion promotion, fatigue resistance, and frictional properties.