KR20130073269A - Sliding matrials comprising solid lubricants with non-spherical shape - Google Patents

Abstract

PURPOSE: A sliding member with solid lubricant particles of non-spherical shapes is provided to apply various shapes of solid lubricant particles as components of a sliding bearing, thereby strengthening the performance of an anti-abrasion film and reducing abrasion. CONSTITUTION: A sliding member (100) with solid lubricant particles (123) of non-spherical shapes comprises a base (101) and one or more sliding layers (102). The sliding layers are formed on the base. The sliding layers include a resin bonding agent and the solid lubricant particles. The solid lubricant particles are dispersed inside the resin bonding agent. The solid lubricant particles are formed into non-spherical shapes.

Description

SLIDING MATRIALS COMPRISING SOLID LUBRICANTS WITH NON'SPHERICAL SHAPE}

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

Sliding members mostly consist of a material having a modified surface that optimizes sliding properties. In one example, a sliding bearing (aka Turcite, tactical) is attached to the drive of the machine tool and used to slide and move smoothly on a lane, and includes a resin binder and a solid filler.

Sliding bearings generally form a composite by mixing a spherical shape of solid filler, in particular bronze particles, with a PTFE polymer. Such a sliding bearing is first formed by the sliding motion of the drive unit the polymer component to form a plate-shaped wear protection film. However, the conventional spherical shape of solid lubricant particles initially plays a role of supporting the antiwear film, but as time passes, the antiwear film is no longer supported. Furthermore, when the initial PTFE wear protection film is destroyed during a long time driving, there is a problem that a rapid increase in wear occurs when the spherical solid lubricant particles located inside are exposed to the outside.

On the other hand, in order to improve the wear resistance in the past, the main object of the study was to change the type or component of the solid filler, or to change the content of the solid lubricant added. However, there is a limit in improving the wear resistance and lubricity of the sliding member when driving for a long time.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sliding member in which wear resistance and lubrication performance are remarkably improved by variously changing the shape of solid lubricant particles, which are 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, the sliding layer comprising a resin binder and solid lubricant particles dispersed within the resin binder, wherein the solid lubricant particles are non-spherical. It provides a sliding member having a shape of.

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

The solid lubricant particles may have an ellipsoid, a tetrahedron, a hexahedron, a triangular pole, a square pole, a cylinder, an ellipse pole, a polygonal pole, a needle, a disc, a zigzag, a bracket, or an amorphous shape.

It is also possible for the solid lubricant particles to have a particle size in which the longest length of the particles ranges from 1 μm to 30 μm.

The solid lubricant particles are selected from the group consisting of soft metals, plate-like ceramics and amorphous materials, for example Cu, Pb, bronze, Ag, Au, SnBi, MoS ₂ , graphite, SiC, hexagonal boron nitride (hBN), glass or Mixtures of these are used.

According to one example of the invention, the content of the solid lubricant particles may be in the range of 10-40% by volume of the total sliding layer material.

In addition, the resin binder is preferably selected from the group consisting of PTFE (polytetrafluoroethylene), 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 a variety of shapes of the solid lubricant particles, which are components of the sliding bearing used in the sliding drive of the machine tool, for example, a machine tool, the action of the anti-wear film is enhanced by 40 to 40 ~. It can reduce wear by as much as 65%.

1 shows a sliding plate and a sliding member attached to a sliding drive 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 needle-like solid lubricant particles are dispersed in a resin binder, according to an embodiment of the present invention.
4 is a cross-sectional view of a sliding member in which elliptical and needle-shaped solid lubricant particles are dispersed in a resin binder, according to one embodiment of the present invention.
FIG. 5 is a cross-sectional view of a sliding member in which bracket-like solid lubricant particles having both ends of the bend are dispersed and disposed in the resin binder, according to one embodiment of the present invention.

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

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

As shown in Fig. 1, a sliding member such as a sliding bearing (also known as sliding plate, turcite, tactile) is attached to the drive of a machine tool and used to slide and move smoothly on a guide way. This sliding member prevents abrasion 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.

2 illustrates the configuration of the sliding member of FIG. 1 described above in detail. The sliding member of FIG. 2 has a structure in which spherical shapes of solid lubricant particles are dispersed in a resin binder.

The solid lubricant particles disposed inside the sliding member play a large role in 1), 1) serving as a support for preventing the destruction of the plate-shaped abrasion-resistant film produced from the polymer by sliding motion, and 2) high load and impact. It acts as a buffer to absorb and withstand the structure. In addition, 3) serves as a lubricating film to form a new wear protection film with the polymer after the polymer wear protection film is broken.

However, when using the spherical shape of the solid lubricant particles as described above, initially serves as a support of the wear protection film, but as time passes, the rounded surface of the solid lubricant particles does not prevent desorption of the wear protection film. Breakage of the phosphorus wear preventing film occurs. In addition, during the long-term sliding drive, the inner polymer is exposed to the outside as the initial polymer wear-resistant film is destroyed, so that even if the solid particles with lubrication ability, it performs the role of the Third Body Effect at the same time, causing a rapid increase in wear .

In the present invention, among the above-mentioned three roles of the solid lubricant particles, it was conceived that the pin effect for preventing the breakdown of the polymer anti-wear film (eg, PTFE) is the most important role for generating a difference in lubricity and wear resistance. Therefore, in order to strengthen the holding (holding) of the plate-shaped polymer film, instead of the conventional spherical (spherical shape) solid lubricant particles, it is characterized by using non-spherical shape solid lubricant particles of various shapes. It is done.

By using the solid lubricant particles having various shapes, the polymer wear protection film is maintained for a long time without being detached by the above-described pin effect, thereby improving lubricity and reducing wear and greatly improving wear resistance.

The sliding member 100 of the present invention includes a substrate 101 and a sliding layer 102 having at least one layer formed on the substrate.

Here, the sliding layer 102 includes a resin binder 121 and non-spherical solid lubricant particles 123, 124, and 125 having various shapes dispersed within 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, evenly distributed solid lubricant particles can be combined with the polymer (eg PTFE) wear protection film to improve the lubrication performance and wear resistance.

If the solid lubricant particles constituting the sliding layer according to the present invention can have a non-spherical shape to prevent the polymer antiwear film from being detached, there are no particular restrictions on the composition and shape thereof.

For example, the shape of the solid lubricant particles may be an ellipsoid, a tetrahedron, a hexahedron, a triangular pillar, a square pillar, a cylinder, an elliptic pillar, a polygonal pillar, a needle shape, a zigzag shape, a bracket type, or an amorphous shape. In this case, the bracket type may have a bent portion, and the bent portion may exist at one or both ends. In addition, the angle of the bent portion is not particularly limited, 50 to 90 ° range is preferred.

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

In this case, FIGS. 3 to 5 are sliding members using needle-shaped, disc-shaped, bracket-like solid lubricant particles each having a bent portion. In practice, the use of solid lubricant particles that have been processed into non-spherical shapes, such as needle-shaped, disc-shaped, and bracket-type with both ends, serves as a support to hold the initially produced polymer (PTFE) anti-wear film to lubricate PTFE. It can be seen that the film lasts a long time to improve the lubricity of the sliding member and also to improve the wear 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 relatively reduced, which may cause difficulty in film formation. Therefore, in the present invention, by adjusting the size, the amount of use and the shape of the solid lubricant particles to the optimum conditions described below, it is possible to further increase the wear resistance and the lubricity improvement effect of the sliding member.

The average size of the solid lubricant particles is not particularly limited, but for example, the longest length of the particles may have a particle average size ranging from 1 μm to 30 μm. If the average size of the solid lubricant particles exceeds 30 μm, it will interfere with the formation of the polymer antiwear film. In addition, even if the solid particles have their own lubrication ability, since the friction (Friction) is about 4 to 5 times larger than the polymer wear protection film, heat may be generated locally. At this time, since the polymer antiwear film is composed of a polymer and is very vulnerable to heat, the antiwear film may be destroyed by locally generated heat.

In addition, the solid lubricant particles can be used without limitation, conventional solid lubricant components known in the art. As an example, a soft metal, a plate-like ceramic, and an amorphous material may be used. Non-limiting examples of solid lubricant particles that can be used include Cu, Pb, bronze, Ag, Au, SnBi, MoS ₂ , graphite, SiC, hexagonal boron nitride (hBN), glass or mixtures of one or more thereof.

In a typical sliding member, the mixing criteria of the solid lubricant particles is 20 to 40% by volume. In contrast, in the present invention, by enhancing the support role of the solid lubricant particles, it is possible to exert a more improved wear resistance effect while reducing the content of the solid lubricant. In the present invention, the content of the solid lubricant particles may range from 10 to 40% by volume based on 100% by volume of the total sliding layer. In this way, the content of the solid lubricant particles can be extended to a small amount of the region 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 the resin binder 121 is applied thinly on the substrate, and can then produce a wear protection film by sliding motion. In one example, conventional resin binders known in the sliding member art can be used. Preferably, polytetrafluoroethylene (PTFE), polyacrylate, polyimide, epoxy resin, polybenzimidazole, silicone resin or mixtures of one or more thereof may be used, more preferably PTFE.

The content of the resin binder is not particularly limited, and when used with solid lubricant particles, the amount of the resin binder may be in the range of the remaining amount to satisfy 100% by volume of the total sliding layer.

In addition to the components described above, the sliding layer may further comprise conventional additives known in the art, such as lubricants, binders, etc., as needed.

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 made of a polymer or a metal. In this case, the polymer may be composed of the same or different components as the resin binder 121. Further non-limiting examples of metals that can be used may be Al, Cu, Ni, Sn, Zn, Ag, Au, Bi, Fe, or alloys thereof.

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

In addition, the substrate may have a surface roughness as necessary, wherein the surface roughness range (Ra) may be in the range of 1 to 8 μm. Roughness serves to improve the adhesion between the substrate and the sliding layer. Such surface roughness ranges include mechanical treatments such as sand blasting or grinding; It can be achieved 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 applied and formed on the substrate in a non-containing state.

The sliding member according to the present invention can be manufactured according to conventional methods known in the art, except for using solid lubricant particles having various shapes. For one preferred embodiment thereof, the solid lubricant particles may be added to and mixed with a polymer solution dispersed in a solvent or a dispersion medium, and then the mixture may be prepared by applying and drying the mixture on a substrate.

At this time, the solvent or the dispersion medium may be appropriately adjusted in consideration of the polymer component to be used. In addition, the coating method may be a wet coating method, a screen printing method, a dipping method, a spray coating method and the like. In addition, the drying temperature and time are not particularly limited as long as the solvent can be evaporated to form the aforementioned sliding layer.

The thickness of the sliding layer or layers formed as described above may be appropriately adjusted in consideration of the use of the sliding member and wear resistance. In one example, it may range from 10 to 40 μm. In addition, 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, it is not limited to the above-mentioned range and can be adjusted suitably according to the use to apply.

The sliding member according to the present invention can be applied to all of the fields in which two metals are attached to a friction and sliding portion to facilitate reciprocating motion. For example, it may be used for a sliding bearing, a sliding plate, or a sliding rail, and more specifically, may be applied 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 >

Sliding bearings of Examples 1 to 4 were prepared using needle-shaped solid filler particles having a needle-like, elliptical, one end bent or both ends bent, and PTFE. As a control, a sliding bearing of Comparative Example using spherical solid filler particles was prepared. In order to evaluate the wear resistance and lubrication improvement of the sliding bearing, a wear test was performed as shown in Table 2 below.

The wear test was performed using Plint's TE-77 reciprocating tester, which is widely used. At this time, in order to clearly distinguish the difference in the shape of the solid lubricant particles, test conditions other than the shape was performed under the same conditions.

The size and the amount of the filler were the same in both Examples and Comparative Examples, the maximum length was used 20 ~ 30㎛, solid filler amount was used 30 ~ 40% by volume. Test conditions are shown in Table 1 below.

In addition, after the test was performed at least five times for reproducibility, the amount of wear (wear depth) is shown in Table 2 as an average value thereof.

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

Filler shape Wear (μm) Average Comparative example rectangle 9.7 Example 1 Needle 4.6 Example 2 Disc Type 5.8 Example 3 Bracket shape with one end bend 3.8 Example 4 Bracket shape with both ends bent 3.4

As a result of the experiment, Examples 1 to 4 all showed an excellent wear improvement effect compared to the comparative example. More specifically, it was confirmed that Example 1 has an improvement effect of 53%, 40% of Example 2, 61% of Example 3, and 65% of Example 4 compared to the amount of wear of the comparative example.

Claims (11)

materials; And at least one sliding layer formed on the substrate,
The sliding layer comprises a resin binder and solid lubricant particles dispersed within the resin binder,
The solid lubricant particles have a non-spherical shape. The sliding member according to claim 1, wherein the sliding layer has a plurality of solid lubricant particles having the same or different shapes as each other is uniformly disposed in the resin binder. The solid lubricant particle of claim 1, wherein the solid lubricant particles have an ellipsoid, a tetrahedron, a hexahedron, a triangular column, a square column, a cylinder, an ellipse column, a polygonal column, a needle shape, a disc shape, a zigzag shape, a bracket shape, or an amorphous shape. Sliding member. The sliding member of claim 1, wherein the solid lubricant particles have a particle size of 1 μm to 30 μm in the longest length of the particles. The sliding member of claim 1 wherein the solid lubricant particles are selected from the group consisting of soft metals, plate-shaped ceramics, and amorphous materials. The sliding member according to claim 5, wherein the solid lubricant particles are selected from the group consisting of Cu, Pb, bronze, Ag, Au, SnBi, MoS ₂ , graphite, SiC, hexagonal boron nitride (hBN) and glass. . The sliding member according to claim 1, wherein the content of the solid lubricant particles is in the range of 10-40% by volume based on the total volume% of the sliding layer. The sliding member of claim 1, wherein the resin binder is selected from the group consisting of PTFE (polytetrafluoroethylene), polyacrylate, polyimide, epoxy resin, polybenzimidazole, and silicone resin. The sliding member of claim 1 wherein the thickness of the sliding layer or layers is in a range from 10 to 40 μm. The sliding member according to claim 1, wherein the substrate is the same or different polymer or metal as the resin binder. The sliding member of claim 1, wherein the sliding member is a sliding bearing, a sliding plate, or a sliding rail.

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