KR101858143B1 - Sliding matrials comprising solid lubricants with non­spherical shape - Google Patents

Abstract

The present invention relates to a substrate; And at least one sliding layer formed on the substrate, wherein the sliding layer comprises a resin binder and solid lubricant particles dispersed within the resin binder, wherein the solid lubricant particles are non-spherical The sliding member has a shape of a curved surface.
In the present invention, by varying the shape of the solid lubricant particles, wear resistance and lubrication performance of the sliding member can be greatly improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a sliding member including a solid lubricant particle having a non-spherical shape (SLIDING MATRIX COMPRISING SOLID LUBRICANTS WITH NONSPHERICAL SHAPE)

The present invention relates to a sliding member improved in wear resistance and lubricity by variously applying the shape of solid lubricant particles, which is one of the main components of the sliding member.

The sliding member is mostly composed of a material having a modified surface that optimizes the sliding characteristics. For example, a sliding bearing (aka, Turcite, Tacide) is attached to a driving part of a machine tool and is used to smoothly slide and move on a guiding lane, including a resin binder and a solid filler.

In general, sliding bearings form spherical shape solid fillers, especially composites by mixing bronze particles with PTFE polymers. The slide bearing of this sliding bearing first forms a plate-like abrasion-resistant film with a polymer component by the sliding motion of the driving part. However, the spherical solid lubricant particles of the prior art faithfully perform the function of supporting the anti-wear film at first, but can not support the anti-wear film over time. Furthermore, since the initial PTFE abrasion-resistant film is broken during long-time driving, when the spherical solid lubricant particles located inside are exposed to the outside, rapid wear is increased.

On the other hand, in order to improve the abrasion resistance, the main object of the present invention is to change the kind and component of the solid filler or to change the content of the solid lubricant to be added. However, there has been a limit in improving wear resistance and lubricity of the sliding member during long-time driving.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sliding member in which abrasion resistance and lubrication performance are remarkably improved by variously changing the shape of solid lubricant particles as one of the main components of the sliding member.

The present invention relates to a substrate; And at least one sliding layer formed on the substrate, wherein the sliding layer comprises a resin binder and solid lubricant particles dispersed within the resin binder, wherein the solid lubricant particles are non-spherical The sliding member has a shape of a curved surface.

Here, the plurality of solid lubricant particles having the same or different shapes as the sliding layers are uniformly arranged in the resin binder.

The solid lubricant particles may have an ellipsoidal shape, a tetrahedron shape, a hexagonal shape, a triangular shape, a square shape, a cylindrical shape, an elliptical shape, a polygonal shape, an acicular shape, a disc shape, a zigzag shape, a bracket shape or an amorphous shape.

It is also possible that the solid lubricant particles have a particle size ranging from 1 [mu] m to 30 [mu] m in the longest length of the particles.

The solid lubricant particles are ductile metal, plate-shaped ceramic and is selected from the group consisting of an amorphous material, for example a Cu, Pb, bronze, Ag, Au, SnBi, MoS _2, graphite, SiC, hexagonal boron nitride (hBN), glass or Mixtures of these are used.

According to one embodiment of the invention, the content of the solid lubricant particles can range from 10 to 40% by volume of the total sliding layer material.

The resin binder is preferably selected from the group consisting of polytetrafluoroethylene (PTFE), polyacrylate, polyimide, epoxy resin, polybenzimidazole, and silicone resin.

The sliding member according to the present invention can be used as a sliding bearing, a sliding plate, or a sliding rail.

As described above, in the present invention, by applying various shapes of solid lubricant particles, which are components of a sliding member, for example, a sliding bearing used by being attached to a sliding drive unit of a machine tool, It is possible to reduce abrasion of about 65%.

1 shows a sliding plate and a sliding member attached to a sliding driving part of a machine tool.
2 is a cross-sectional view of a conventional sliding member in which spherical solid lubricant particles are dispersed in a resin binder.
3 is a cross-sectional view of a sliding member in which acicular solid lubricant particles are dispersed in a resin binder, according to one embodiment of the present invention.
4 is a cross-sectional view of a sliding member in which elliptical and acicular solid lubricant particles are dispersed in a resin binder, according to one embodiment of the present invention.
5 is a cross-sectional view of a sliding member in which bracket-shaped solid lubricant particles with both end bent portions are dispersed and disposed in a resin binder, according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments or drawings described herein, but may be embodied or altered in other forms.

1 shows a sliding plate and a sliding member attached to a sliding driving part of a machine tool.

As shown in FIG. 1, a sliding member such as a sliding bearing (aka, sliding plate, turcite, takade) is attached to a driving part of a machine tool and is used to smoothly slide and move on a guide way. Such a sliding member prevents wear by forming a polymer anti-wear film between two flat objects moving by sliding motion, and generally includes spherical solid lubricant particles and a polymer binder.

The above-described structure of the sliding member of Fig. 1 is shown in more detail in Fig. The sliding member of Fig. 2 has a structure in which spherical shape solid lubricant particles are dispersedly disposed in a resin binder.

The solid lubricant particles disposed inside the sliding member largely serve three roles: 1) to serve as a support for preventing the destruction of the plate-shaped wear-resistant film produced from the polymer by the sliding motion; and 2) And serves as a buffer to maintain the tolerance structure. 3) It serves as a lubricant film to form a new anti-wear film together with the polymer after the anti-abrasion film is destroyed.

However, if spherical solid lubricant particles are used as described above, the solid lubricant particles initially serve as a support for the anti-wear film, but the rounded surface of the solid lubricant particles can not prevent desorption of the anti- The anti-abrasion film is broken. In addition, during sliding operation for a long period of time, the inner polymer particles are exposed to the outside due to the destruction of the initial polymer wear-resistant film, and even the solid particles having lubrication ability perform the third body effect role simultaneously, resulting in a rapid increase in wear .

Among the three roles of the solid lubricant particles, the present invention has focused on the fact that the pin effect preventing the destruction of the polymer abrasion-resistant film (e.g., PTFE) is the most important role in generating the difference in lubricity and abrasion resistance. Accordingly, in order to enhance the holding of holding the polymer film in the shape of a plate, it is preferable to use non-spherical solid lubricant particles having various shapes instead of the spherical shape solid lubricant particles .

When the solid lubricant particles having various shapes are used, the polymer anti-wear film can be maintained for a long time without detachment due to the pin effect, thereby improving the lubricity and reducing abrasion, thereby greatly improving the wear resistance.

A sliding member (100) of the present invention includes a base material (101) and a sliding layer (102) having at least one layer formed on the base material.

The sliding layer 102 includes a resin binder 121 and various non-spherical solid lubricant particles 123, 124, and 125 dispersed in the resin binder.

The sliding layer 102 preferably has a structure in which a plurality of solid lubricant particles 123, 124, and 125 having the same or different shapes are uniformly disposed in the resin binder 121. In this way, the solid lubricant particles must be uniformly distributed so that they can be well combined with the polymer (e.g., PTFE) abrasion-resistant film to further improve the lubrication performance and wear resistance.

The solid lubricant particles constituting the sliding layer according to the present invention have a non-spherical shape, so that the composition and shape of the solid lubricant particles are not particularly limited as long as they can prevent the polymer wear-resistant film from being desorbed.

For example, the shape of the solid lubricant particles may be an ellipsoid, a tetrahedron, a hexahedron, a triangular prism, a quadrangular prism, a cylinder, an elliptical prism, a polygonal prism, an acicular shape, a zigzag shape, a bracket shape or an amorphous shape. At this time, the bracket type may have a bent portion, which may exist at one end or both ends. Also, the angle of the bent portion is not particularly limited, and is preferably in the range of 50 to 90 degrees.

3 to 5 are side cross-sectional views illustrating a configuration of a sliding member according to an embodiment of the present invention.

At this time, Figs. 3 to 5 constitute a sliding member by using needle-shaped, disc-shaped, and solidified lubricant particles in the form of brackets each having bent portions at both ends. Actually, solid lubricant particles processed into a non-spherical shape such as needle-shaped, disk-shaped, and bracket type having a bent portion at both ends serve as a support for holding an initially produced polymer (PTFE) It can be confirmed that the film lasts for a long time to improve the lubricity of the sliding member and improve the abrasion resistance (see Table 2).

On the other hand, if the number of solid lubricant particles is too large or too large, wear may be increased by the Third Body Effect, and the amount of the polymer may be decreased, which may make film formation difficult. Therefore, in the present invention, by adjusting the size, the amount and the shape of the solid lubricant particles to the optimal conditions described below, the wear resistance and the lubricity improving effect of the sliding member can be further improved.

The average size of the solid lubricant particles is not particularly limited. For example, the longest particle size of the solid lubricant particles may have an average particle size ranging from 1 to 30 mu m. When the average size of the solid lubricant particles exceeds 30 mu m, it interferes with the formation of the polymer wear-resistant film. Even if the solid particles have their own lubrication ability, the frictional force is 4 to 5 times larger than the polymer abrasion prevention film, so that local heat may be generated. At this time, since the polymer abrasion-resistant film is composed of polymer and is very vulnerable to heat, the abrasion-resistant film may be destroyed by locally generated heat.

In addition, the solid lubricant particles can be used without limitation to conventional solid lubricant components known in the art. For example, a soft metal, a plate-like ceramic, or an amorphous material can be used. Using Non-limiting examples of possible solid lubricant particles, the Cu, Pb, bronze, Ag, Au, SnBi, MoS _2, graphite, SiC, hexagonal boron nitride (hBN), glass or combinations, such as one or more mixtures.

In a general sliding member, the mixing ratio of the solid lubricant particles is 20 to 40% by volume. By contrast, in the present invention, by enhancing the role of the support of the solid lubricant particles, the content of the solid lubricant can be reduced, and the improved wear resistance effect can be exhibited. In the present invention, the content of the solid lubricant particles may be in the range of 10 to 40% by volume based on 100% by volume of the entire sliding layer. Thus, the content of the solid lubricant particles can be expanded to a small amount and used for various purposes.

The resin binder 121 constituting the sliding layer according to the present invention is not particularly limited as long as it is a material which is thinly coated on a substrate and can produce a wear-resistant film by sliding motion. For example, conventional resin binders known in the sliding member art can be used. Preferably, PTFE (polytetrafluoroethylene), polyacrylate, polyimide, epoxy resin, polybenzimidazole, silicone resin or a mixture of at least one of these may be used, more preferably PTFE.

The content of the resin binder is not particularly limited and may be in the range of the balance satisfying 100 volume% of the entire sliding layer when mixed with the solid lubricant particles.

In addition to the above-mentioned components, the sliding layer may further include conventional additives known in the art, for example, lubricants, binders, and the like, if necessary.

The substrate 101 according to the present invention may be composed of a single layer or a plurality of layers.

The substrate 101 may be composed of a polymer or a metal. At this time, the polymer may be composed of the same or different components as the resin binder 121. Also, non-limiting examples of usable metals may be Al, Cu, Ni, Sn, Zn, Ag, Au, Bi, Fe, or an alloy thereof.

The thickness of the substrate may range from 1 to 20 mu m, but is not particularly limited thereto.

The substrate may also have surface roughness as required, wherein the surface roughness range (Ra) may range from 1 to 8 탆. The roughness serves to improve the adhesion between the substrate and the sliding layer. Such surface roughness ranges include mechanical treatments such as sandblasting or grinding; For example, by chemical treatment such as phosphate coating or slight etching.

The sliding member according to the present invention may include an intermediate layer between the substrate and the sliding layer, or may be formed on the substrate without being coated.

The sliding member according to the present invention can be manufactured according to a conventional method known in the art, except that solid lubricant particles having various shapes are used. In one preferred embodiment thereof, solid lubricant particles are added to a polymer solution dispersed in a solvent or a dispersion medium, followed by mixing, and then the mixture is applied on a substrate and dried.

At this time, the solvent or dispersion medium can be appropriately adjusted in consideration of the polymer component to be used. The coating method may be a wet coating method, a screen printing method, a dipping method, a spray coating method, or the like. Further, the drying temperature and the time are not particularly limited as long as the solvent can be evaporated so that the above-described sliding layer can be formed.

The thickness of the sliding layer or layers formed as described above can be appropriately adjusted in consideration of the use of the sliding member and the wear resistance. For example, it may range from 10 to 40 mu m. Further, the thickness of the sliding member of the present invention may be in the range of 0.1 to 20 mm, preferably in the range of 0.5 to 10 mm. However, the present invention is not limited to the above-mentioned range, and can be suitably adjusted according to the intended application.

The sliding member according to the present invention can be applied to both fields where two metals are frictionally attached to a sliding portion to facilitate reciprocating motion. For example, it can be used as a sliding bearing, a sliding plate, or a sliding rail, and more particularly, as a sliding bearing in a combustion engine or a sliding bearing of a machine tool.

Hereinafter, embodiments of the present invention will be described in more detail. It should be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It is possible.

≪ Examples 1 to 4 >

The sliding bearings of Examples 1 to 4 were fabricated using needle-shaped, elliptical, one-end bent portions or bracket-shaped solid filler particles and PTFE designed in the present invention. A sliding bearing of the comparative example using spherical solid filler particles was prepared as a control. In order to evaluate the wear resistance and the lubricity improvement of such sliding bearings, wear tests were performed as shown in Table 2 below.

The abrasion test was carried out using a conventional Plint TE-77 reciprocating tester. In order to clearly distinguish the difference in the shape of the solid lubricant particles, test conditions other than the shape were performed under the same conditions.

The maximum size and the amount of the filler were the same for both Examples and Comparative Examples, and the amount of the solid filler was 30 to 40% by volume. The test conditions are shown in Table 1 below.

In addition, the test was carried out at least five times for reproducibility, and the abrasion amount (abrasion depth) as an average value thereof is shown in Table 2 below.

Lubrication condition Dry friction Load 120 N (1.06 MPa) time 4.0 hr frequency 5 Hz Stroke 10mm

Filler shape Wear (탆) average Comparative Example rectangle 9.7 Example 1 Needle 4.6 Example 2 Disc (Disc) 5.8 Example 3 A bracket shape having a bent portion once 3.8 Example 4 Bracket shape with both ends bent 3.4

As a result of the test, all of Examples 1 to 4 exhibited excellent wear-improving effect as compared with Comparative Examples. More specifically, it was confirmed that Example 1 had an improvement of about 53% of the wear amount of the comparative example, 40% of the Example 2, 61% of the Example 3, and 65% of the Example 4.

Claims (11)

materials; And a sliding member having at least one sliding layer formed on the substrate,
Wherein the sliding layer includes a resin binder and solid lubricant particles dispersed in the resin binder,
Wherein the solid lubricant particles are in the form of a bracket having both end bent portions, wherein the solid lubricant particles have a particle size with a longest particle length of 1 占 퐉 to 30 占 퐉,
Wherein the content of the solid lubricant particles is in the range of 10 to 40% by volume based on the entire volume% of the sliding layer. The sliding member according to claim 1, wherein the plurality of solid lubricant particles having the same or different shapes as the sliding layers are uniformly arranged in the resin binder. delete delete The sliding member according to claim 1, wherein the solid lubricant particles are selected from the group consisting of a soft metal, a plate-like ceramic, and an amorphous material. The method of claim 5, wherein the solid lubricant particles have a sliding member, characterized in that is selected from Cu, Pb, bronze, Ag, Au, SnBi, MoS _2, graphite, SiC, hexagonal boron nitride (hBN), and the group consisting of glass . delete The sliding member according to claim 1, wherein the resin binder is selected from the group consisting of polytetrafluoroethylene (PTFE), polyacrylate, polyimide, epoxy resin, polybenzimidazole, and silicone resin. The sliding member according to claim 1, wherein the thickness of the sliding layer or layers ranges from 10 to 40 mu m. The sliding member according to claim 1, wherein the base material is a polymer or metal which is the same as or different from the resin binder. The sliding member according to claim 1, wherein the sliding member is a sliding bearing, a sliding plate, or a sliding rail.

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