Self-lubricating articulation element made from a composite material and operating under high dynamic loadings

Abstract

The element is formed from the winding of a fabric of small thickness ranging between 20 ?m and 150 ?m and mixed with a resin containing fillers. The fabric has the form of strips having a width ranging between 5 mm and 200 mm, with the strips being crossed in several layers.

Claims

1. A self-lubricating joint element adapted to operate under high dynamic loads, comprising: a resin comprising fillers, and a plurality of superimposed strips of fabric mixed with the resin, such that the joint element is homogeneous across an entire thickness of the joint element, each strip having a thickness ranging between 20 ?m and 150 ?m, and a width ranging between 5 mm and 200 mm, said strips being crossed in several layers by filament winding with respect to adjacent strips.

2. The element of claim 1, wherein each strip has a thickness ranging between 20 ?m and 130 ?m.

3. The element of claim 1, wherein a crossing angle of the crossed strips ranges between 10? and 90?.

4. The element of claim 1, wherein a crossing angle of the crossed strips ranges between 30? and 86?.

5. The element of claim 1, wherein the fabric comprises a synthetic fabric.

6. The element of claim 1, wherein the resin comprises epoxy, ester vinyl, polyester, phenolic, or polyimide.

7. The element of claim 1, wherein the fillers comprise PTFE, MoS2, or graphite.

8. The element of claim 7, wherein the fillers amount to between 5 and 70% of the volume.

9. The self-lubricating joint element of claim 1, wherein the joint element is ring-shaped.

10. The self-lubricating joint element of claim 1, wherein the joint element is capable of operating under dynamic loads greater than 60 MPa.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) The invention is discussed hereafter in further detail by means of the accompanying drawings, among which:

(2) FIG. 1 shows the winding of a fabric of small thickness according to the features of the invention;

(3) FIG. 2 is a very simplified view showing the fabric winding according to the prior state of the art to obtain a determined thickness;

(4) FIG. 3 is a view similar to FIG. 2 showing the fabric winding according to the invention to obtain the same determined thickness;

(5) FIG. 4 is a partial side view of wound strips of a self-lubricating joint element according to the invention;

(6) FIG. 5 is a sectional view of a ring-shaped self-lubricating joint element of the present invention; and

(7) FIG. 6 is an enlarged view of a circumferential section of the ring-shaped joint element according to the present invention.

DETAILED DESCRIPTION

(8) According to the invention, the self-lubricating joint element (1), such as a ring, for example, is made from the winding of a synthetic fabric of small thickness (T4) ranging between 20 ?m and 150 ?m and advantageously between 20 ?m and 130 ?m.

(9) The fabric, which appears in the form of strips (4), is mixed with a resin (2) of epoxy, ester vinyl, polyester, phenolic, polyimide, or other type.

(10) This resin (2) comprises fillers (3) of PTFE, MoS2, graphite or other types, by on the order of from 5 to 70% of the volume. The aim is to obtain a product which is homogeneous across its entire thickness.

(11) The fabric strips (4) have a width (W4) ranging between 5 mm and 200 mm and are wound on a mandrel of determined diameter, according to the filament winding technique.

(12) The strips (4) are wound and crossed in several layers, the crossing angle (A4) ranging between 10? and 90? and advantageously between 30? and 86?.

(13) Reference should be made to FIG. 3, which shows a winding in the form of 9 plies of 100 ?m as opposed to a winding according to the state of the art in the form of 3 plies of 300 ?m.

(14) It should be noted that the fabric intended to be mixed with the resin may be made of taffeta, satin, twill or a cloth, without excluding other fiber textures.

(15) Reference should be made to the following tests in the case of a joint in the form of a self-lubricating composite ring receiving an axis of characteristic 16 NC 6 CT Ra: 04. Shaft diameter: 30 mm Width of the guide member: 20 mm Motion: alternated rotation over 90? Pressure calculated in projected area: 80 MPa Sliding speed: 8 mm/s Friction coefficient>0.25

(16) The tests have the following results:

(17) Prior State of the Art Winding at 90? Width of the fabric strip used: 1,200 mm Fabric thickness: 0.30 mm Outer diameter of the ring to be obtained: 36 mm Obtained wear>0.5 mm Friction coefficient<0.2 mm Number of cycles: 30,000.

(18) According the Features of the Invention: Crossed winding Width of the fabric strip used: 30 mm Fabric thickness: 0.10 mm Outer diameter of the ring to be obtained: 36 mm Obtained wear: 0.4 mm Friction coefficient<0.1 mm Number of cycles: 365,000.