JPH1194084A - Sliding part coating material and piston ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sliding part coating material for securing excellent abrasion resistance even under the strict sliding conditions such as the high temperature and the high load without increasing attacking property to a counterpart material, having excellent lubricity to the counterpart surface when direct contact of a substrate and the counterpart material is partially generated, and capable of realizing excellent adhesion resistance and abrasion resistance at low cost without using any complicated mechanism. SOLUTION: A sliding part coating material 1c having a heat resistant resin as a base material and having a sliding surface 1s is formed into a two-layer structure formed by laminating a front surface layer if having 50 wt.% or more of heat resistant resin taking as the base and containing 5 wt.% or more of antimony oxide as reinforcing grains having the diameter in the range of 1 to 5 μm, and a front lower layer 1u taking heat resistant resin as a base material, having 20 wt.% or more of heat resistant resin to be taken as a base material, and containing 30 to 80 wt.% of solid lubricant as a lubricity improving component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating material for a sliding portion, and more particularly to a coating for a piston ring for an internal combustion engine and the like, which adheres to a base metal by direct contact with a mating material and deterioration of a lubricating state. The present invention relates to a coating material for a sliding portion suitable for preventing the occurrence of wear and a piston ring having the coating material coated on its surface.

[0002]

The operating environment of an internal combustion engine has become severer year by year with the recent improvement in performance of the internal combustion engine.

[0003] Generally, the pistons of these internal combustion engines include:
A piston ring is installed to ensure the airtightness of the combustion chamber and to control the lubricating oil inside the cylinder. Especially in high-temperature and high-load conditions, the aluminum alloy used as the piston material is The phenomenon that the piston material is worn on the surface of the ring may occur, which may cause problems such as a decrease in airtightness of the combustion chamber and an increase in oil consumption.

In order to prevent this, in some engines, a solid lubricant or the like is applied to the upper and lower surfaces of the piston ring in order to prevent the direct contact between the piston ring base material and the piston and to improve the lubrication state. Is applied.

Conventional solid lubricating coating materials include:
For example, a solid lubricating film containing an appropriate amount of a solid lubricant such as MoS ₂ (molybdenum disulfide), graphite, or PTFE (polytetrafluoroethylene) using an epoxy resin or a polyamideimide (PAI) resin as a binder is used. Are known.

However, such a conventional solid lubricating film is particularly lubricated when the underlayer is partially exposed and sliding occurs on the coexisting surface of the exposed underlayer and the film component remaining in the underground concave portion. Because of the necessity of ensuring the performance, the solid lubricant component is included in a large amount, so the bondability is poor, and under more severe sliding conditions, the progress of wear of the coating itself becomes severe and sufficient durability cannot be obtained. As a result, there has been a problem that adhesion and wear between the piston ring substrate and the piston may occur at an early stage.

On the other hand, if carbon fiber or glass fiber is blended in the same manner as a general resin composite material to improve the wear resistance of the coating, the base material is partially exposed and direct contact with the mating material occurs. Not only the lubricity is reduced, but also the aggressiveness of the mating material is increased.If this is used as a covering material for the piston ring, the mating piston may be worn. There was a problem.

Therefore, in the case of an aluminum alloy piston, under such severe conditions, higher cost measures such as anodizing the sliding surface of the piston with the piston ring must be adopted. Was the actual situation.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the conventional problems described above, and is excellent even under severe sliding conditions such as high temperature and high load without increasing the aggressiveness to a mating material. Unprecedented by providing a sliding part covering material that ensures abrasion resistance and at the same time has excellent lubricity with the mating surface when direct contact between the base and the mating material partially occurs at the same time The purpose is to realize anti-adhesion and wear resistance performance at low cost without using a complicated mechanism.

[0010]

In order to achieve the above object, the present inventors investigated the friction and wear behavior of such a resin-bonded coating material in detail, and found that the resin-bonded coating material was adhered by coating. In order to further improve the wear prevention performance, it is necessary to improve the wear resistance of the coating material itself in the area where the coating material is sliding with a single phase, and to improve the lubrication performance after the abrasion progresses and the base material is exposed. Investigation from both aspects of improvement is necessary, and it has been found that the coating properties required in each region are clearly different, and the present invention has been completed.

That is, the sliding portion covering material according to the present invention is based on a heat-resistant resin as described in claim 1, wherein the base heat-resistant resin comprises
0% by weight or more and at least 1
A surface layer containing 5 μm or more of antimony oxide of 5 μm, a heat-resistant resin as a base material, a heat-resistant resin as a base material of 20% by weight or more, and a solid lubricant as a lubricity improving component of at least 30 to 80% by weight; % Of the lower surface layer is laminated.

Further, in the embodiment of the sliding portion covering material according to the present invention, as described in claim 2,
The surface layer may contain a solid lubricant as a lubricity improving component, and the content thereof may be equal to or less than the solid lubricant content in the lower surface layer.

[0013] Similarly, in an embodiment of the sliding portion covering material according to the present invention, as described in claim 3,
The lower surface layer may contain antimony oxide having a particle size of 1 to 5 μm as reinforcing particles, and the content thereof may be equal to or less than the antimony oxide content in the surface layer.

Similarly, in an embodiment of the sliding portion covering material according to the present invention, as described in claim 4,
The thickness of the surface layer may be larger than the thickness of the lower surface layer, and the total thickness may be 5 to 25 μm.

[0015] Similarly, in an embodiment of the sliding portion covering material according to the present invention, as described in claim 5,
As a base treatment, the base material may be subjected to a phosphate treatment with a surface roughness Rmax of 1 to 10 μm.

[0016] The piston ring according to the present invention comprises:
According to a sixth aspect of the present invention, at least a required surface of the piston ring base material is coated with the sliding portion coating material according to any one of the first to fifth aspects. I have.

[0017]

According to the first aspect of the present invention, the coating material for a sliding portion comprises a heat-resistant resin as a base material, wherein the heat-resistant resin serving as a base is at least 50% by weight and at least reinforced. A surface layer containing 5% by weight or more of antimony oxide having a particle size of 1 to 5 μm as a particle, and a heat-resistant resin (not necessarily the same as the heat-resistant resin of the surface layer) as a base material. When the resin is 20% by weight or more and at least 30 to 80 solid lubricant is used as a lubricity improving component.
It has a multi-layer structure in which the lower surface layer containing weight% is laminated, but in this case, by using a heat-resistant resin for the base material, it can be used for high temperature sliding parts. By adding at least antimony oxide as a reinforcing particle to the surface layer using such a heat-resistant resin as a base material, the coating material becomes excellent in abrasion resistance in a sliding region in a single phase. Further, by adding a solid lubricant as at least a lubricity improving component to the lower surface layer, lubrication performance when a part of the base is exposed can be secured at the same time.

The antimony oxide to be added to the surface layer is not too high in hardness as compared with carbon fiber or glass fiber used in a general resin composite material, and the particle shape is close to spherical.
Since there is no edge, the aggressiveness to the mating material is small, and even when a relatively soft metal such as aluminum is combined as the mating sliding member, the wear is not promoted.

However, when the added amount of antimony oxide is less than 5% by weight, the effect of sufficiently improving the abrasion resistance is small. Conversely, when the added amount is increased, the proportion of the base heat-resistant resin becomes less than 50% by weight. Then, the amount of abrasion increases rather due to the decrease in the bonding strength of the coating.

The particle size of antimony oxide to be added is 1
If it is less than μm, the effect of improving the wear resistance is small, and
When m exceeds m, it is difficult to uniformly disperse in the coating, and it may be difficult to form a stable coating material for the sliding portion.

When the amount of the solid lubricant to be added to the lower surface layer is less than 30% by weight, a sufficient lubricating action when the underlayer is partially exposed cannot be obtained. If the ratio of the heat-resistant resin as the base material exceeds 20% by weight, the retention of the added component is remarkably reduced and the component easily falls off from the substrate, preventing adhesion and abrasion. Performance cannot be maintained for a long time.

According to an embodiment of the present invention, the surface layer contains a solid lubricant as a lubricity improving component and the content of the solid lubricant is lower than the surface layer. The solid lubricant content can be less than or equal to the solid lubricant content, but especially when used in a severely lubricated environment, the solid lubricant is appropriately added as a lubricity improving component to the surface layer as described above. By containing it, the friction loss at the time of sliding is further reduced, and the durability of the coating material for the sliding portion is further improved due to the reduction of the frictional heat generated thereby.

However, if the amount of addition is larger than the amount added to the lower surface layer, the lubricity is improved, but the bondability of the film itself is impaired, and as a result, it is not preferable for the improvement of the wear resistance of the film. Becomes

Further, in the embodiment of the coating material for a sliding portion of the present invention, as described in claim 3, antimony oxide having a particle size of 1 to 5 μm as a reinforcing particle is contained in the lower surface layer. Although the content can be less than or equal to the antimony oxide content in the surface layer, especially when used under sliding conditions under a high surface, antimony oxide is used in the same manner as the surface layer. The addition of the compound further enhances the abrasion resistance while maintaining the excellent lubricity of the lower surface layer. In addition, since the amount of the lubricating component remaining in the base recess when the base is partially exposed is relatively reduced, a sufficient lubricating effect cannot be obtained.

Further, in an embodiment of the sliding portion covering material of the present invention, as described in claim 4, the thickness of the surface layer is larger than the thickness of the lower surface layer and the entire thickness. Is 5
The thickness of the surface layer is thicker than the thickness of the lower surface layer, and thus, the wear resistance of itself is mainly excellent until immediately before the underlying metal is exposed. Since the sliding is performed on the surface layer, the durability of the covering material for the sliding portion is further improved. With respect to the overall film thickness, if the thickness is less than 5 μm, it becomes difficult to form a uniform film, and at the same time, the effect of the added components tends not to be sufficiently obtained.
If it exceeds 300, the strength of the coating as a whole will decrease, and the film will tend to fall off from the substrate at an early stage.

Furthermore, in the embodiment of the sliding portion coating material of the present invention, as described in claim 5, the substrate is treated with a phosphate having a surface roughness Rmax of 1 to 10 μm as a base treatment. In this way, the adhesive strength of the coating material for the sliding portion with the underlying metal and the retention of the added component when the underlying material is partially exposed are further improved. However, if the roughness of the undercoat layer is less than Rmax 1 μm, this effect is not sufficient, and if it exceeds 10 μm, it is difficult to form a uniform film, which may cause early peeling and falling off of the film.

Furthermore, the piston ring according to the present invention has the following features.
By coating the surface of the piston ring base material with the coating material for a sliding part according to any one of the above, without increasing the aggressiveness to the piston which is the mating material,
Even under severe piston sliding conditions such as high load, the direct contact between the piston ring substrate and the piston surface is prevented for a long period of time, and the direct contact between the piston ring substrate and the piston surface is partially prevented. Even in the case of occurrence, lubrication with the piston surface is excellent, and unprecedented excellent anti-adhesion and wear resistance can be realized at low cost without using a complicated mechanism.

[0028]

According to the coating material for a sliding portion of the present invention, as described in claim 1, a heat-resistant resin is used as a base material, the heat-resistant resin serving as a base is 50% by weight or more, and A surface layer containing at least 5% by weight of antimony oxide having a particle size of 1 to 5 μm as reinforcing particles and a heat-resistant resin (not necessarily the same as the heat-resistant resin of the surface layer) as a base material are used as a base. 20% by weight or more of heat-resistant resin and at least 3 solid lubricants as lubricity improving component
Since it has a multi-layer structure in which the lower surface layer containing 0 to 80% by weight is laminated, it can be used for a high-temperature sliding portion by using a heat-resistant resin for the base material. Also, by adding antimony oxide as at least reinforcing particles to the surface layer based on such a heat-resistant resin, the coating material has excellent wear resistance in a region where the coating material slides in a single phase. Further, it is possible to simultaneously secure the lubrication performance when a part of the base is exposed by adding a solid lubricant as at least a lubricity improving component to the lower surface layer, Excellent abrasion resistance under severe sliding conditions such as high temperature and high load without increasing the aggressiveness to the mating material, and at the same time, direct contact between the substrate and the mating material partially occurs. Excellent lubrication with the mating surface can be achieved, and unprecedented excellent anti-adhesion and abrasion resistance can be realized at low cost without using a complicated mechanism. Is obtained.

And, as described in claim 2,
The surface layer contains a solid lubricant as a lubricity improving component and its content is not more than the solid lubricant content in the lower surface layer, so that it can be used particularly in an environment with severe lubrication. Even so, by appropriately adding a solid lubricant as a lubricity improving component to the surface layer as described above, it is possible to further reduce the friction loss during sliding, and thereby reduce the frictional heat generation. Thus, a remarkably excellent effect that the durability of the coating material for the sliding portion can be further improved is brought about.

Further, as described in claim 3, the lower surface layer contains antimony oxide having a particle size of 1 to 5 μm as reinforcing particles and the content thereof is not more than the antimony oxide content in the surface layer. By maintaining the excellent lubricity of the lower surface layer by adding antimony oxide in the same manner as the surface layer, even in the case of using under particularly high sliding conditions. However, the abrasion resistance can be further enhanced, and the life of the entire sliding portion covering material can be further improved, resulting in a remarkably excellent effect.

Further, as described in claim 4,
By making the thickness of the surface layer thicker than the thickness of the lower surface layer and making the overall thickness 5 to 25 μm, the surface mainly having excellent wear resistance until immediately before the underlying metal is exposed. It is possible to perform sliding in layers, and it is possible to further improve the durability of the coating material for the sliding portion, and the thickness of the entire coating material should be 5 to 25 μm. Thereby, it is possible to sufficiently exert the effect of the added additive components, and to obtain a remarkably excellent effect that it is possible to obtain a coating material for a sliding portion with more stable characteristics.

Further, as described in claim 5, the substrate has a surface roughness Rmax of 1 to 10 μm as a base treatment.
By performing the phosphate treatment of m, it is possible to further improve the adhesion strength of the coating material to the underlying metal and the retention of the added components when the underlying material is partially exposed. This is a remarkably excellent effect.

In the piston ring of the present invention, as described in claim 6, the surface of the piston ring base material is coated with the sliding portion coating material according to any one of claims 1 to 5. Therefore, even under severe piston sliding conditions such as high temperature and high load, the piston ring base material and the piston Contact is prevented, and even when direct contact between the piston ring substrate and the piston surface partially occurs, it is possible to achieve excellent lubrication with the piston surface, which is an unprecedented excellent A remarkably excellent effect is obtained that the anti-adhesion and abrasion resistance can be realized at low cost without using a complicated mechanism.

[0034]

Next, examples of the present invention will be described in more detail together with comparative examples.

Examples 1 to 5 First, a PAI (polyamide imide) resin was selected as a heat-resistant resin serving as a base material, and this was dissolved in n-methyl-2-pyrrolidone and xylene as a solvent.
Solution of the surface layer of Examples 1 to 5, by blending the components to the antimony oxide (Sb 2 _{O 3)} such as a composition comprising appropriately indicated on the surface layer of each column, the sliding portion dressings Was adjusted.

Next, after surface adjustment such as degreasing is performed on the upper surface of the piston ring base material made of spring steel, the surface roughness R
A manganese phosphate treatment with a max of about 3 μm is performed, and the solution prepared as described above is spray-coated on the lower surface layer and the surface layer in this order, dried and then fired at about 180 to 220 ° C. As shown in FIG. 2, the surface layer 1f has a thickness of about 7 μm on the upper surface of the piston ring base material 1b and the lower surface layer 1f.
The test piece of the piston ring 1 coated with the sliding portion coating material 1c having a thickness of about 3 μm and a total thickness of about 10 μm was prepared.

Comparative Examples 1-4, Comparative Examples 7-8 The same PAI resin used in the above Examples was replaced with n-methyl-2.
-In a solution of pyrrolidone and xylene as a solvent,
The antimony oxide (Sb) shown in each column of the surface layer and the lower surface layer of Comparative Examples 1 to 4 and Comparative Examples 7 to 8 in Table 1
Each component was blended so as to have a composition appropriately containing ₂ O ₃ ) and the like, and a solution of the coating material for the sliding portion was prepared.

Next, after surface adjustment such as degreasing is performed on the upper surface of the piston ring base material made of spring steel, the surface roughness R
A manganese phosphate treatment with a max of about 3 μm is performed, and the solution prepared as described above is spray-coated on the lower surface layer and the surface layer in this order, and then dried by heating at about 180 to 220 ° C. Similarly to the above, the thickness of the surface layer (1f) is about 7 μm, the thickness of the lower surface layer (1u) is about 3 μm, and the total thickness is about 10 μm on the upper surface of the piston ring substrate (1b).
The test piece of the piston ring (1) coated with the coating material (1c) for the sliding portion of m was prepared.

COMPARATIVE EXAMPLES 5-6 The same PAI resin used in the above Examples was replaced with n-methyl-2.
-In a solution of pyrrolidone and xylene as a solvent,
Each component was blended so as to have the composition shown in the column of the surface layer of Comparative Examples 5 and 6 in Table 1 to prepare a solution of the coating material for the sliding portion.

Next, after surface adjustment such as degreasing is performed on the upper surface of the piston ring base material made of spring steel, the surface roughness R
A manganese phosphate treatment with a max of about 3 μm is performed, and the solution adjusted as described above is spray-coated and dried, and then heated and fired at about 180 to 220 ° C., as shown in FIG. A test piece of the piston ring 11 was prepared in which the upper surface of the base material 11b was coated with a sliding portion coating material 11c having a thickness of about 10 μm.

[0041]

[Table 1]

(Adhesion Wear Test) Examples 1 to 5 and Comparative Example 1
As shown in FIG. 3, the test pieces of the piston rings 1 and 11 obtained in Steps 8 to 8 were used as cutting materials 2 from actual aluminum alloy pistons. (Set by 3), a single-piece adhesion wear test was performed, and the time until the occurrence of adhesion on the sliding surfaces 1 s and 11 s was compared with the wear amount of the mating material 5 hours after the start of the test. Table 3 shows the results.

[0043]

[Table 2]

[0044]

[Table 3]

As is clear from Table 3, Example 1 of the present invention
Examples 5 to 5 are Comparative Examples 1 and 2 in which the composition of the surface layer deviates from the present invention, Comparative Examples 3 and 4 in which the composition of the lower surface layer deviates from the present invention, and sliding without a two-layer structure. It can be seen that the durability time until the occurrence of adhesion is greatly improved as compared with Comparative Examples 5 and 6, in which the coating material composition does not change between the initial stage and when the undercoat is partially exposed.

In Comparative Examples 7 and 8, the durable time until the occurrence of adhesion is the same as that of the embodiment of the present invention, but the wear amount of the mating piston is significantly increased as compared with the embodiment of the present invention. ,
From these facts, it was confirmed that the coating material for a sliding portion of the present invention has excellent performance that cannot be obtained with a conventional coating material for a sliding portion.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional explanatory view of a piston ring showing an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional explanatory view of a conventional piston ring that has been subjected to a resin-binding coating process.

FIG. 3 is an explanatory cross-sectional view showing an outline of a single-piece adhesive wear test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piston ring 1b Piston ring base material 1c Covering material for sliding part 1f Surface layer 1u Lower surface layer 2 Cutting material from piston (partner material) 3 Heater

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16J 9/28 F16J 9/28 (72) Inventor Masahiko Shioda 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. 72) Inventor Katsuhiro Kishi 2 Nissan Motor Co., Ltd., 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa

Claims (6)

[Claims] 1. A coating material for a sliding portion comprising a heat-resistant resin as a base material, wherein the heat-resistant resin as a base is 50% by weight or more, and at least reinforcing particles include antimony oxide having a particle size of 1 to 5 μm. A surface layer containing at least 20% by weight of a heat-resistant resin and a lower surface layer containing at least 20% by weight of a heat-resistant resin as a base material and at least 30 to 80% by weight of a solid lubricant as a lubricity improving component. A sliding portion covering material having a multilayer structure formed by lamination. 2. The sliding part according to claim 1, wherein the surface layer contains a solid lubricant as a lubricity improving component and the content thereof is not more than the solid lubricant content in the lower surface layer. Coating material. 3. A particle having a particle size of 1 to 5 as a reinforcing particle in a lower surface layer.
The coating material for a sliding part according to claim 1, wherein the coating material contains antimony oxide of μm and the content thereof is not more than the content of antimony oxide in the surface layer. 4. The sliding part according to claim 1, wherein the thickness of the surface layer is larger than the thickness of the lower surface layer, and the total thickness is 5 to 25 μm. Coating material. 5. A base material having a surface roughness Rmax as a base treatment.
The coating material for a sliding portion according to any one of claims 1 to 4, wherein a phosphate treatment of 1 to 10 µm has been performed. 6. A piston ring, wherein the surface of a piston ring base material is coated with the coating material for a sliding portion according to any one of claims 1 to 5.