JP2001343022A - Double sliding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double sliding material superior in conformability and capable of preventing seizure due to early stage wear by the worn powder of a protection layer and due to local collision of a counter material in a plain bearing coating the protection layer on the surface of a bearing alloy layer. SOLUTION: The protection layer 10 is composed of a solid lubricator and a binder comprising a thermoplastic resin dissolvable in a polar solvent and a thermosetting resin. When the thermoplastic resin and the thermosetting resin are dissolved in the solvent, they are harmoniously mixed in a very minute unit near a molecule, and the binder has intermediate nature between the nature of the thermoplastic resin and that of the thermosetting resin. Thus, in the case that the binder is worn by sliding to the counter shaft, the surface of the protection layer 10 is deeply damaged by the worn powder and can be prevented from wearing at an early stage. In addition, since the binder has proper hardness, it can maintain good conformability, even when the counter shaft has local collision, the protection layer 10 is prevented from wearing at the early stage and can prevent risk bringing an alloy layer 9 into metal contact with the counter shaft since the protection layer 10 hardly extends.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer sliding material having a sliding surface coated with a protective layer containing a solid lubricant.

[0002]

2. Description of the Related Art For example, a bearing for a crankshaft of a marine engine or an automobile engine is provided with a C on a steel plate.
A sliding bearing in which a u-based bearing alloy or an Al-based bearing alloy is joined is used. In this plain bearing for engines, a protective layer has been coated on the bearing surface for the purpose of improving conformability and wear resistance.

[0003] For example, Japanese Patent Application Laid-Open No. 2000-27868 discloses that a sliding surface of a marine engine is coated with self-lubricating tetrafluoroethylene on the bearing surface. Further, Japanese Patent Application Laid-Open No. 58-10
No. 8299 discloses that in a plain bearing of an automobile engine, the bearing surface is coated with a protective layer composed of a solid lubricant such as graphite or molybdenum disulfide and a binder such as a phenol resin or an epoxy resin. .

[0004]

The above-mentioned phenolic resin and epoxy resin are both thermosetting resins, but the thermosetting resin is hard and therefore has poor adaptability. In particular, under conditions of near lubrication when starting the engine, abrasion powder generated by sliding wear with the crankshaft may damage the protective layer and cause early wear.

To prevent this, it is conceivable that the protective layer is made of a soft thermoplastic resin, for example, tetrafluoroethylene. However, since the thermoplastic resin is soft, it has poor abrasion resistance. Also, if the crankshaft hits the end of the flexible plain bearing locally, 10μ
It is said that the thermoplastic resin coated very thinly on the order of m becomes thinner and stretched at the local contact portion and wears out early, and as a result, the bearing alloy and the crankshaft come into metallic contact with each other to cause seizure. There is a risk.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multi-layer sliding material capable of preventing early wear of a protective layer due to abrasion powder and seizure due to local contact of a mating material. .

[0007]

The invention according to claim 1 is characterized in that the protective layer is constituted by a solid lubricant and a binder made of a thermoplastic resin and a thermosetting resin soluble in a polar solvent. I do. According to this configuration, when the thermoplastic resin and the thermosetting resin are dissolved in a solvent, they are mixed in an extremely fine unit close to the molecule, and as a binder, the properties of the thermoplastic resin and the properties of the thermosetting resin are reduced. It comes to have an intermediate property with the property.

For this reason, even if the mating material hits a local area, the protective layer is difficult to spread and has relatively high strength. It can be effectively prevented. In addition, since the binder has an appropriate hardness, good conformability can be maintained, and when the binder is worn by sliding with a mating material, the surface of the protective layer is deeply damaged by the abrasion powder, and is worn early. Can also be prevented.

According to the second aspect of the present invention, the ratio of the thermoplastic resin is set to 1 to 100 parts by volume with respect to 100 parts by volume of the thermosetting resin. The reason for this is that if the thermoplastic resin content is less than 1 part by volume, the binder becomes very close to the properties of the thermosetting resin, the conformability is poor, and premature wear due to abrasion powder tends to occur. Further, when the content exceeds 100 parts by volume, the binder becomes close to the property of the thermoplastic resin, and the hardness of the protective layer decreases,
As a result, abrasion resistance is reduced, and metal contact due to local contact of the mating material is more likely to occur.

In the invention of claim 3, the content of the solid lubricant in the protective layer is set to 80% by volume or less based on 100% by volume of the total composition. Solid lubricants have the effect of lowering the coefficient of friction of the protective layer. When the solid lubricant exceeds 80% by volume,
This is because the proportions of the thermosetting resin and the thermoplastic resin functioning as a binder are reduced, so that the solid lubricant cannot be retained, the strength of the protective layer is reduced, and the wear resistance is reduced.

In the present invention, the protective layer contains 5% by volume or less of hard particles based on 100% by volume of the total composition. Hard particles improve the wear resistance of the protective layer. If the content exceeds 5% by volume, the attacking property against the counterpart material will be enhanced, and the counterpart material will be damaged or the protective layer will be worn due to the damage of the counterpart material.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a slide bearing for a crankpin of a marine engine will be described below with reference to the drawings. FIG. 3 shows a bearing device for a crankpin of a crankshaft of a marine engine. The bearing device 1 for a crankpin includes a sliding housing 3 provided in a bearing housing 2. Bearing housing 2
Is an upper housing 5 provided on the crank rod 4.
And a lower housing 6 attached to a lower portion of the upper housing 5. As shown in FIG. 2, the sliding bearing 3 is configured by vertically abutting two sliding bearings (hereinafter, referred to as half bearings) 7 formed in a semi-cylindrical shape.

As shown in FIG. 1, the half bearing 7 has an alloy layer 9 made of an Al-based bearing alloy on a steel back metal 8 and further has a surface (bearing surface) on the alloy layer 9. Protective layer 10
Is coated. The protective layer 10 is applied by an appropriate coating means such as spraying, roller coating, or brush coating.

The protective layer 10 is composed of a solid lubricant and a binder made of a thermoplastic resin and a thermosetting resin, and has a thickness of 5 to 40 μm. Desirably 10
30 μm. As a solid lubricant constituting the protective layer 10, polytetrafluoroethylene (hereinafter, PTF) is used.
E), molybdenum disulfide (MoS ₂ ), tungsten disulfide (WS ₂ ), graphite (hereinafter, Gr) and the like are used. As the thermoplastic resin, polyether sulfone (hereinafter, PES) soluble in a polar solvent such as dimethylacetamide (hereinafter, DMAC) and N-methyl-2-pyrrolidone (hereinafter, NMP) is used, As the thermosetting resin, polyamideimide (hereinafter, PAI) and epoxy (hereinafter, EP), which are also soluble in a polar solvent, are used.

Next, a method of manufacturing the half bearing 7 will be described. First, an Al alloy for joining and an Al-based bearing alloy plate are stacked on a steel plate to be a back metal 8 and pressed by a roll rolling method to form an alloy layer 9, and a bimetal having the alloy layer deposited on the steel plate is manufactured. I do. Form small pieces of predetermined dimensions from this bimetal,
The small pieces are bent into a semi-cylindrical shape to form an intermediate product before coating. Then, after subjecting the intermediate product to predetermined machining, pretreatments such as degreasing and pickling are performed.

On the other hand, a polar solvent such as DMAC or NMP is mixed with a solid lubricant such as PTFE, MoS ₂ , WS ₂ , or Gr, and in some cases, hard particles such as TiO ₂ , a thermoplastic resin such as PES, PAI, EP or the like. Is added and mixed and stirred to produce a dispersion. The thermoplastic resin and the thermosetting resin are dissolved in the solvent and are mixed in extremely fine units close to molecules. In this case, the solid lubricant is preferably 80% by volume or less, and the ratio of the thermoplastic resin is preferably 1 to 100 parts by volume with respect to 100 parts by volume of the thermosetting resin. When hard particles are added, the hard particles are preferably 5% by volume or less.

Then, the intermediate product after the above pretreatment is treated with 120
C. and apply the dispersion onto the alloy layer 9 of the intermediate product by spraying. Thereafter, the intermediate product is heated to 180 ° C., and the dispersion is dried and fired. By this firing, the solvent evaporates, and the half bearing 7 in which a binder made of a thermoplastic resin and a thermosetting resin and a protective layer 10 containing a solid lubricant and hard particles are firmly adhered to the surface of the alloy layer 9 are formed. can get.
At this time, the thickness of the protective layer 10 is 20 μm.

Table 1 below shows the friction coefficient of the sliding bearing with the protective layer 10 according to the present embodiment and the conventional sliding bearing with the protective layer deposited thereon, and the friction / wear test and the seizure test. The results of the implementation are shown. In Table 1, the values in parentheses in the binder column are the volume ratio of the thermoplastic resin to the thermosetting resin.

The friction / wear test was carried out using a thrust tester under the conditions shown in Table 2, and the wear amount two hours after the start of operation was measured. The coefficient of friction indicated the coefficient of friction at the end of the test. The seizure test was also performed using the thrust type tester under the conditions shown in Table 3. The bearing surface pressure was increased by 3 MPa, and the bearing was operated for 0.5 hour at each bearing surface pressure. The bearing surface pressure when it exceeded or the current of the motor driving the shaft showed an abnormal value was defined as the seizure load.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

As is clear from Table 1, it is understood that the product of the example is superior to the product of the comparative example in all of the coefficient of friction, the wear resistance and the anti-seizure property. Comparative Example Product 2,
4, 5, and 7 and the example products 9 and 10 contain the same amount of resin as the binder, that is, 40% by volume, but the comparative example products 2, 4, and 7
Comparative Example 5 contains only 40% by volume of the thermoplastic resin, whereas Examples 9 and 10 contain the thermosetting resin and the thermoplastic resin, respectively. It contains 20% by volume and a total of 40% by volume.

Then, the wear amount of the comparative products 2, 4, 5, 7
Is 16 to 18 μm, but in Examples 9 and 10, 1
0 to 14 μm, and the seizure load is comparative example 2,
In the case of 4, 5 and 7, the pressure is 9 to 15 MPa.
In the case of 10, it is as large as 18 to 21 MPa, and the product of the example is superior.

Further, when comparing the comparative example product 1 and the working example product 8, the total amount of both resins is 80% by volume.
Comparative Example 1 contains only 80% by volume of the thermosetting resin, while Example 8 contains 60% by volume and 20% by volume of the thermosetting resin and the thermoplastic resin, respectively. . The comparative example product 1 and the example product 8 have the same abrasion resistance, but the example product 8 is superior in non-seizure property.

Next, regarding the content of the resin as the binder, in Comparative Example 3, the solid lubricant content was 9%.
Since it is as large as 0% by volume, the binder contains only 10% by volume. For this reason, the binding property of the solid lubricant by the binder is poor, the strength is insufficient, and the wear amount exceeds 20 μm. On the other hand, in Examples 8 to 11, the amount of the solid lubricant is 80% by volume or less, and the amount of wear is small because the solid lubricant is well bonded by the binder.

In Examples 8 to 11, the ratio of the thermoplastic resin (PES) was set to the same as that of the thermosetting resin (PAI, E
PS) 2.6 to 100 parts by volume for 100 parts by volume,
Good results were obtained for both wear resistance and non-seizure properties. In addition, it turns out that the ratio of a thermoplastic resin is the preferable range which can obtain favorable abrasion resistance and non-seizure property with 100-100 volume parts of thermosetting resin being favorable.

In addition, when the comparative examples 2 and 6 are compared, it can be seen that the addition of hard particles is effective in improving abrasion resistance and anti-seizure properties. By comparing the comparative example product 6 with the example product 11, in addition to the addition of the hard particles, when the binder is made of a thermoplastic resin and a thermosetting resin, the wear resistance and the anti-seizure property are further improved. It is understood that improvements can be made.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be extended or modified as follows. Solid lubricants are PTFE, MoS ₂ ,
It is not limited to WS ₂ and Gr. The thermoplastic resin is not limited to PES. The thermosetting resin is not limited to PAI and EP.

The application of the present invention is not limited to bearings for marine engines, but is also applicable to polyester resins and vinyl resins.
Hard particles are not limited to TiO ₂ , but AlO ₃ , BN, SiO
_{4 is} also possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sliding bearing showing one embodiment of the present invention.

FIG. 2 is a perspective view of a sliding bearing.

FIG. 3 is a partial sectional view of a marine engine crank.

[Explanation of symbols]

In the figure, 1 is a crank pin bearing device, 3 is a sliding bearing,
7 is a half bearing, 8 is a backing metal, 9 is an alloy layer, and 10 is a protective layer.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobutaka Hiramatsu 2 Sanage-cho, Kita-ku, Nagoya City Inside (72) Inventor Takayuki Shibayama 2 Sanage-cho, Kita-ku Nagoya City Daido Metal Industry Co., Ltd. F term (reference) 3J011 BA13 NA01 QA04 QA05 SB13 SC20 SE05 SE06 SE07

Claims (4)

[Claims] 1. A multilayer sliding material comprising a bearing alloy layer whose surface is covered with a protective layer, wherein the protective layer is formed of a solid lubricant, a thermoplastic resin soluble in a polar solvent, and a thermosetting resin. A multilayer sliding material characterized by comprising a binder comprising: 2. The multilayer sliding material according to claim 1, wherein the proportion of the thermoplastic resin is 1 to 100 parts by volume based on 100 parts by volume of the thermosetting resin. 3. The multilayer sliding material according to claim 1, wherein the content of the solid lubricant in the protective layer is 80% by volume or less based on 100% by volume of the total composition. 4. The multi-layer slide according to claim 1, wherein the protective layer contains 5% by volume or less of hard particles with respect to 100% by volume of the total composition. Moving material.