JP6863176B2 - Manufacturing method of sliding member - Google Patents

Description

The present invention relates to a method of manufacturing a sliding member.

Conventionally, sliding members disclosed in Patent Document 1 are known. This sliding member includes a base material made of a steel material and a sliding layer formed on the base material via a base layer. The sliding layer contains a binder resin and a solid lubricant. The binder resin is composed of an epoxy resin and a phenol resin. The solid lubricant is composed of particulate molybdenum disulfide (MoS ₂ ), particulate polytetrafluoroethylene (PTFE), and particulate polyethylene.

This sliding member can be used for a propeller shaft or the like in which the sliding layer slides with the mating material in the presence of a lubricant.

Japanese Unexamined Patent Publication No. 2013-189569

In order to ensure reliability, the sliding member is desired to have further improved sliding characteristics such as seizure resistance and wear resistance. In particular, in a sliding member whose temperature becomes high due to frictional heat or the like, it is required to improve the sliding characteristics by suppressing the dropping of polyethylene.

The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object to be solved to provide a sliding member capable of exhibiting more excellent sliding characteristics.

The method for manufacturing a sliding member of the present invention is a method for manufacturing a sliding member for manufacturing a sliding member that slides with a mating material in the presence of a lubricant.
A modification step of plasma-treating particulate ultra-high molecular weight polyethylene with a gas species such as oxygen and helium or nitrogen and helium to modify the surface of the ultra-high molecular weight polyethylene.
A surface treatment step of applying a silane coupling treatment to the ultra-high molecular weight polyethylene, and
A composition preparation step of preparing a composition for a sliding layer containing the solid lubricant containing the ultra-high molecular weight polyethylene modified by the modification step and a binder resin.
It is characterized by comprising a sliding layer forming step of providing the composition for a sliding layer on a base material to form a sliding layer that slides with the mating material and obtaining a sliding member.

According to the test results of the inventors , in the sliding member obtained in the present invention, the solid lubricant is unlikely to fall off from the binder resin when sliding with the mating material. The reason for this is that the surface of the ultra-high molecular weight polyethylene in the sliding layer has been modified by plasma treatment.

For plasma treatment, it is preferable that the gas species are oxygen and helium. In this case, according to the test results of the inventors, the ultra-high molecular weight polyethylene modified by the modification step is more difficult to fall off from the binder resin.

For plasma treatment, it is also preferable that the gas species are nitrogen and helium. In this case, according to the test results of the inventors, the ultra-high molecular weight polyethylene modified by the modification step is unlikely to fall off from the binder resin.

After reforming step, before the composition preparation step, if you perform a surface treatment step of applying a silane coupling treatment to ultra high molecular weight polyethylene, according to the inventors' test results, ultra high molecular weight polyethylene binder resin It is even more difficult to drop out from.

According to the manufacturing method of the present invention, a sliding member capable of exhibiting excellent sliding characteristics can be manufactured .

FIG. 1 is a chemical formula of ultra-high molecular weight polyethylene before plasma treatment. FIG. 2 is a graph showing the results of XPS analysis of ultra-high molecular weight polyethylene before plasma treatment. FIG. 3 is a graph showing the XPS analysis results of ultra-high molecular weight polyethylene after plasma treatment in which the gas types are oxygen and helium. FIG. 4 is a graph showing the XPS analysis results of ultra-high molecular weight polyethylene after plasma treatment in which the gas types are nitrogen and helium. FIG. 5 shows a general chemical formula of a polyamide-imide resin. FIG. 6 is a schematic perspective view showing a state of a pin-on disc reciprocating test. FIG. 7 is a 500-fold SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 1. FIG. 8 is a 500-fold SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 2. FIG. 9 is a 500-fold SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 3. FIG. 10 is a 500-fold SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 4. FIG. 11 is a 500-fold SEM image photograph of the sliding layer of Test 1 in the sliding member of Example 5. FIG. 12 is a 500-fold SEM image photograph of the sliding layer of Test 1 in the sliding member of the comparative example. FIG. 13 is a cross-sectional view showing a state of the swash plate × shoe test.

The ultra-high molecular weight polyethylene shown in FIG. 1 has OH groups generated in the side chains and terminals by plasma treatment using oxygen and helium as gas types. Further, in the ultra-high molecular weight polyethylene shown in FIG. 1, _two NH groups are generated in the side chain and the terminal by plasma treatment using nitrogen and helium as gas types.

FIG. 2 shows the XPS analysis results of the ultra-high molecular weight polyethylene before the plasma treatment, FIG. 3 shows the XPS analysis results of the ultra-high molecular weight polyethylene after the plasma treatment using oxygen and helium as gas types, and FIG. 4 shows the gas types. The XPS analysis result of the ultra-high molecular weight polyethylene after plasma treatment with nitrogen and helium is shown. In this way, the presence or absence of reactive groups such as _{OH group and NH 2 group can be confirmed by XPS analysis.}

In ultra-high molecular weight polyethylene in which reactive groups such as OH groups and NH ₂ groups are generated, it is considered that the reactive groups are likely to bond with the functional groups of the binder resin. For example, when the binder resin is a polyamide-imide resin having a general chemical formula shown in FIG. 5, NH ₂ groups and COOH groups are present in its side chains and terminals. When this polyamide-imide resin comes into contact with the modified ultra-high molecular weight polyethylene, it is considered that the polyamide-imide resin and the modified ultra-high molecular weight polyethylene are chemically bonded by an amide bond or a hydrogen bond.

Therefore, in the sliding member of the present invention, more ultra-high molecular weight polyethylene is likely to remain on the surface of the sliding layer, and excellent sliding characteristics can be exhibited.

<Modification process>
Plasma treatment is performed by using a high-frequency power source to generate glow plasma of _{N 2} plasma (gas type: N ₂ , He) or O ₂ plasma (gas type: O _{2, He).}

<Composition preparation process>
(Binder resin)
Binder resin has the retention of solid lubricant that makes it difficult to remove the solid lubricant, durability against shearing force that repeatedly acts under the layered coating (hardness as a base), wear resistance that is hard to break, heat resistance, etc. Demonstrate. As the binder resin, a polyimide resin, an epoxy resin, a phenol resin, or the like can be adopted. As the polyimide-based resin, polyamide-imide (PAI), polyimide, or the like can be adopted. Considering the cost and characteristics, it is optimal to use PAI as a binder resin.

(Solid lubricant)
The solid lubricant is retained in the binder resin and exhibits low shear and a low coefficient of friction on the outermost surface. As the solid lubricant, fluororesin, molybdenum dioxide, graphite, ultra-high molecular weight polyethylene and the like can be adopted. Fluororesin and ultra-high molecular weight polyethylene form a film on the sliding surface of the sliding layer and transfer to the mating material to improve slipperiness. Molybdenum dioxide and graphite have a crystal structure with low shearing force to improve slipperiness and realize low friction under high load. According to the experimental results of the inventors, the fluororesin has sliding properties such as wear resistance and seizure resistance, but has oil repellent properties, and the contact angle of the lubricating oil is relatively large. large. On the other hand, although ultra-high molecular weight polyethylene is inferior to fluororesin in sliding characteristics, it has lipophilic characteristics and the contact angle of the lubricating oil is relatively small. Further, as the solid lubricant, soft metals such as ultra-high molecular weight polyethylene, melamine cyanurate (MCA), calcium fluoride, copper and tin can be adopted.

The ultra-high molecular weight polyethylene preferably has an average molecular weight of 1 million to 7 million. The ultra-high molecular weight polyethylene is preferably contained in the range of 5 to 100% by volume, more preferably in the range of 15 to 60% by volume, based on 100% by volume of the binder resin. If the amount of ultra-high molecular weight polyethylene added is small, the effect of addition is reduced, and if it is large, the amount of supplementation by the binder resin is reduced, particles are shed, and the sliding characteristics of the sliding layer are reduced.

The specific gravity of the ultrahigh molecular weight polyethylene is preferably 0.92 to 0.96. The ultra-high molecular weight polyethylene preferably has a particle size of 30 μm or less, and more preferably 15 μm or less, from the viewpoint of surface smoothness and wear resistance.

(Additives, etc.)
The sliding layer may have an additive in addition to the binder resin and the solid lubricant. As the additive, those that improve the hardness of the sliding layer, such as hard particles such as titanium dioxide, calcium tertiary phosphate, alumina, silica, silicon carbide, and silicon nitride, can be adopted.

Sliding layer, ZnS, may contain a sulfur-containing metal compound such as Ag ₂ S as an extreme pressure agent. Further, the sliding layer may have a surfactant, a coupling agent, a processing stabilizer, an antioxidant and the like. The lubricant preferably contains hydrocarbon oil.

<Sliding layer forming process>
In the sliding layer forming step, depending on the type of coating method such as spray coating and roll coating, sliding with a solvent such as n-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, or xylene is optional. It is possible to dilute the layer composition and adjust the viscosity and the concentration of solids. It is possible to form a sliding layer by coating a base material with a diluted product of the composition for a sliding layer and then drying and firing the base material.

<Surface treatment process>
As the silane coupling agent used in the silane coupling treatment, it is preferable to use one having a reactive group such as an amino acid. For the silane coupling treatment, a stock solution of a silane coupling agent may be used, or a solution obtained by dissolving the stock solution in a solvent such as water or an aqueous alcohol solution may be used. In the silane coupling treatment, the modified ultra-high molecular weight polyethylene is put into a Henschel mixer, a Ladyge mixer, etc. and stirred, and the stock solution or solution of the silane coupling agent is dropped or spray-sprayed during stirring. This can be done by further stirring and then drying. The presence or absence of silane coupling treatment can also be confirmed by XPS.

Hereinafter, Examples 1 to 5 embodying the present invention and Comparative Examples will be described. First, the following materials were prepared.
Binder resin: Polyamide-imide resin varnish Solid lubricant: Particle-like ultra-high molecular weight polyethylene (UHPE particles) (average particle diameter 10 μm), MoS ₂ , Graphite silane coupling agent: Amino-based ethoxysilane (standard), Amino-based ethoxysilane (Responsiveness)

As a reforming step, UHPE particles were subjected to plasma treatment under the conditions shown in Table 1, and No. 1 to 5 UHPE particles were used. No. The UHPE particles of No. 6 were not modified.

In addition, No. The UHPE particles 2 to 5 were subjected to a silane coupling treatment under the conditions shown in Table 1 as a surface treatment step after the modification step. The silane coupling treatment was carried out in the following order.

First, an alcohol aqueous solution containing 10% by mass of water and 90% by mass of methyl alcohol was prepared, a stock solution of 1% by mass of each silane coupling agent was added to the alcohol aqueous solution with respect to each UHPE particle, and this was stirred. A silane coupling agent solution was used.

No. 1 in Henschel mixer. 2 to 5 UHPE particles were added and stirred, and the silane coupling agent solution was added dropwise over several tens of minutes during stirring, and the mixture was further stirred for 10 minutes. After this, each UHPE particle was taken out and dried at 100 to 150 ° C. for 30 to 90 minutes. Each agglomerated UHPE particle was pulverized by a ball mill. In this way, the No. 1 subjected to the silane coupling treatment. 2-5 UHPE particles were obtained. No. The UHPE particles of No. 1 were not subjected to a surface treatment step.

As a composition preparation step, the binder resin and each solid lubricant are blended in the blending ratios shown in Table 2, and after stirring well, they are passed through a three-roll mill to form the sliding layer compositions of Examples 1 to 5 and Comparative Examples. The thing was prepared. The solid lubricant is No. It consists of any of the UHPE particles 1 to 6, MoS ₂ and graphite.

The following sliding layer forming step was performed. First, the composition for each sliding layer is diluted with a solvent to obtain a diluted product, and each diluted product is coated on a base material made of a steel material, dried, and fired at 220 ° C. × 1.5 hours. Diluted. After that, surface grinding was performed to make the film thickness the same, and a sliding layer having a film thickness of 25 μm was formed. In this way, the sliding members of Examples 1 to 5 and Comparative Examples were obtained.

Each sliding member was subjected to the following tests 1 to 3.
<Test 1 (Pin-on disc reciprocating test)>
As shown in FIG. 6, each sliding member 10 is placed on a plate 1 whose upper surface can be heated. In this state, each sliding member 10 has a sliding surface 10a as an upper surface. On the sliding surface 10a, a pin 2 made of SUJ2 and having a curvature of 10R at the tip is reciprocated under the conditions of a load of 350 gf, a reciprocating distance of 20 mm, a speed of 2 Hz, and a reciprocating number of 3500 times. At this time, the lubricant 3 containing the hydrocarbon oil is dropped onto the sliding surface 10a.

The residual state of UHPE particles on the surface of the sliding surface 10a of each of the sliding members 10 of Examples 1 to 5 and Comparative Example after Test 1 was confirmed by SEM images. In the sliding member of Example 1, a 500-fold SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 2, a 500-fold SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 3, a 500-fold SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 4, a 500-fold SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of Example 5, a 500-fold SEM image photograph of the sliding layer of Test 1 is shown in FIG. In the sliding member of the comparative example, a 500-fold SEM image photograph of the sliding layer of Test 1 is shown in FIG. From these SEM image photographs, “◯” was added if sufficient UHPE particles remained, and “x” was added if UHPE particles had fallen off, and the results are shown in Table 3.

<Test 2 (Pin-on disc reciprocating test)>
The load condition of Test 1 was set to 350 gf, and the test was conducted in the same manner as in Test 1. The wear depth (μm) of the sliding surface 10a of each of the sliding members 10 of Examples 1 to 5 and Comparative Example after Test 2 was confirmed. The results are also shown in Table 3.

<Test 3 (swash plate x shoe test)>
As shown in FIG. 13, the base material 20 had a swash plate shape of a compressor, and a sliding layer 20a was formed on each base material 20 in the same manner as described above to obtain a swash plate. On the other hand, the shoe 5 made of SUJ2 was held by the holder 4. Then, while adhering the refrigerating machine oil to the surface of the swash plate at an amount of 25 g / min, the swash plate is rotated at a sliding speed of 7 m / sec, and a load of 400 N is applied between the swash plate and the shoe 5 every 5 minutes. , The seizure load (N) between the swash plate and the shoe 5 was investigated. The results are also shown in Table 3.

As can be seen from Table 3, the sliding members of Examples 1 to 5 are superior in wear resistance to the sliding members of Comparative Examples. In particular, the sliding members of Examples 2 to 5 exhibit more excellent wear resistance.

Here, when FIGS. 7 to 11 and 12 are compared, in the sliding member of the comparative example, the dropout mark can be clearly seen as compared with the sliding member of Examples 1 to 5. This indicates that in the sliding member of the comparative example, the surface of the sliding member became hotter than the melting point of the UHPE particles due to frictional heat, and the UHPE particles fell off. On the other hand, in the sliding members of Examples 1 to 5, almost no dropout marks can be confirmed.

Therefore, in the sliding members of Examples 1 to 5, it can be seen that the UHPE particles as the solid lubricant are unlikely to fall off from the binder resin when sliding with the mating material. The reason for this is that the UHPE particles of the solid lubricant in the sliding layer have their surfaces modified by plasma treatment.

In particular, in the sliding members of Examples 2 to 5, UHPE particles as a solid lubricant are unlikely to fall off from the binder resin when sliding with the mating material. The reason for this is that the modified UHPE particles are further subjected to a silane coupling treatment.

Therefore, it can be seen that in the sliding members of Examples 1 to 5, a larger amount of solid lubricant is likely to remain on the surface of the sliding layer, and excellent sliding characteristics can be exhibited. Therefore, it can be seen that if these sliding members are used for the swash plate of the compressor or the like, a more excellent compressor can be obtained.

In the above, the present invention has been described in accordance with Examples 1 to 5, but the present invention is not limited to the above Examples 1 to 5, and can be appropriately modified and applied without departing from the spirit thereof. Needless to say.

For example, in the present invention, in order to improve the adhesion between the base material and the sliding layer, it is possible to perform a degreasing step in which an alkali or the like is brought into contact with the base material. Further, in order to further enhance the adhesion between the base material and the sliding layer, it is possible to form a base layer made of a phosphate such as zinc phosphate or manganese phosphate after the degreasing step.

The present invention can be used for various sliding members, but is particularly suitable for use in swash plates, pistons, sliding bearings, etc. of compressors that become hot due to frictional heat or the like.

2, 5 ... Opponent material (5 ... Shoe)
10 ... Sliding member 20 ... Base material 10a, 20a ... Sliding layer

Claims (2)

A method for manufacturing a sliding member for manufacturing a sliding member that slides with a mating material in the presence of a lubricant.
A modification step in which particulate ultra-high molecular weight polyethylene is subjected to plasma treatment in which the gas species are oxygen and helium to modify the surface of the ultra high molecular weight polyethylene.
A surface treatment step of applying a silane coupling treatment to the ultra-high molecular weight polyethylene, and
A composition preparation step of preparing a composition for a sliding layer containing the solid lubricant containing the ultra-high molecular weight polyethylene modified by the modification step and a binder resin.
Sliding characterized by comprising a sliding layer forming step of providing the composition for a sliding layer on a base material to form a sliding layer that slides with the mating material and obtaining a sliding member. Manufacturing method of parts. A method for manufacturing a sliding member for manufacturing a sliding member that slides with a mating material in the presence of a lubricant.
A modification step in which particulate ultra-high molecular weight polyethylene is subjected to plasma treatment in which the gas species are nitrogen and helium to modify the surface of the ultra high molecular weight polyethylene.
A surface treatment step of applying a silane coupling treatment to the ultra-high molecular weight polyethylene, and
A composition preparation step of preparing a composition for a sliding layer containing the solid lubricant containing the ultra-high molecular weight polyethylene modified by the modification step and a binder resin.
Sliding characterized by comprising a sliding layer forming step of providing the composition for a sliding layer on a base material to form a sliding layer that slides with the mating material and obtaining a sliding member. Manufacturing method of parts.

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