JPH07238936A - Slide bearing material - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the sliding performance of a sliding bearing including a coating layer containing a solid lubricant and an aluminum bearing alloy having a relatively smooth surface. [Structure] Surface roughness 1.0 μm to 4.5 μm Rz
On the surface of the aluminum-based bearing alloy in the range of less than 98% to 55% by weight of solid lubricant and 2 to 45% by weight of thermosetting resin
And a coating layer having a film thickness of 2 to 10 μm and a surface roughness of 5 μm Rz or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide bearing for an internal combustion engine, and more specifically to a slide bearing having a coating layer formed by bonding a solid lubricant with a resin on the surface of an aluminum bearing alloy. Is.

[0002]

2. Description of the Related Art The applicant of the present invention discloses in Japanese Patent Laid-Open No. 4-83914 that MoS is formed on the surface of an aluminum bearing alloy.
2, WS2, solid lubricants such as graphite 90-55
A sliding bearing having a coating layer composed of 10 wt% and 10 wt% to 45 wt% of a polyimide binder was proposed.
In the examples of this publication, the surface of the aluminum-based bearing alloy has a roughness of 4.5 μm due to alkali etching and pickling.
Adjusted to mRz. Further, the description in the specification describes that the thickness of the coating layer is 1 to 25 μm.

[0003]

In the method disclosed in the above-mentioned publication, the surface roughness of the coating layer formed on the surface of the aluminum alloy roughened to enhance the adhesion is 6 μmR.
It became about z. Furthermore, the thickness of the coating layer is 10
It was found that if the thickness exceeds μm, the seizure resistance and wear resistance are deteriorated as compared with the aluminum-based bearing alloy without the coating layer.

Further, the method disclosed in the above-mentioned publication does not disclose the conditions of the coating layer that can provide practical sliding performance when the surface of the aluminum bearing alloy is not roughened. The present inventors formed a coating layer under various conditions on an aluminum-based bearing alloy having a relatively smooth surface, and examined the sliding characteristics. In order for the solid lubricant to exert its performance, the resin coating layer It has been found that it is necessary to properly control the initial friction that depends on the surface roughness and the wear behavior that depends on the thickness. Therefore, it is an object of the present invention to improve the sliding performance of a sliding bearing including a coating layer containing a solid lubricant and an aluminum bearing alloy having a relatively smooth surface.

[0005]

According to the present invention, 98 to 55% by weight of a solid lubricant is formed on the surface of an aluminum-based bearing alloy having a surface roughness of 1.0 μm or more and less than 4.5 μm Rz.
And a thermosetting resin of 2 to 45% by weight, and a film thickness of 2 to
The present invention provides a sliding bearing material provided with a coating layer having a surface roughness of 10 μm and a surface roughness of 5 μmRz or less.

In the present invention, the reason why the surface roughness of the aluminum-based bearing alloy is set to less than 4.5 μmRz is relatively smooth, which is not specifically disclosed in Japanese Patent Application Laid-Open No. 4-83914 of the present applicant. This is because an aluminum-based bearing alloy having a surface can be put into practical use as a sliding bearing with a coating layer, and the surface roughness of the coating layer can be reduced. If the surface roughness is less than 1.0 μmRz, the adhesion of the coating layer will be reduced. The preferable surface roughness is 2 to 4 μmRz. In order to make the aluminum-based bearing alloy have such a surface roughness, a usual rolled material may be degreased and washed, or thereafter, light etching may be performed with acid or alkali.

If the thickness of the coating layer is less than 2 μm, the effect of improving the conformability is lost. On the other hand, when the coating layer has a thickness of more than 10 μm, the abrasion of the coating layer increases and the surface contour of the sliding bearing becomes concentric with the mating shaft. As a result, the action of the oil film is weakened and the seizure resistance deteriorates. Therefore, the film thickness of the coating layer is 2 to 10 μm.
It is necessary to be within the range of, preferably 3 to 8 μ
m, and more preferably 4 to 6 μm.

The surface roughness of the coating layer is 5
When it exceeds μmRz, the coefficient of friction becomes high and fluid lubrication is hindered, so that it is necessary to be 5 μmRz or less. The surface roughness is preferably 3 μmRz or less, more preferably 2 μmRz or less.

MoS2, WS2, graphite, BN and the like can be used as the solid lubricant. These solid lubricants have a low friction coefficient and a stable action, and also have compatibility. In order to reduce the roughness of the resin coating layer, it is preferable to use a fine solid lubricant having an average particle diameter of 2 μm or less, particularly 1 μm or less. When the solid lubricant is less than 55% by weight in the coating layer, the frictional properties are not excellent and seizure easily occurs. On the other hand, the solid lubricant is 9
If it exceeds 8% by weight, the adhesion of the coating layer will be insufficient. The solid lubricant is preferably MoS2, and the amount thereof is preferably 70 to 96% by weight, more preferably 80 to 90% by weight. Further, when it is necessary to suddenly apply the full load at the initial stage of assembling the slide bearing to the internal combustion engine, it is preferable to add 90 to 98% of MoS2 to the coating layer to improve the conformability.

As the thermosetting resin, polyimide, epoxy, phenol resin, etc. can be used.
As the polyimide resin, aromatic polyimide, polyether imide, aromatic polyamide imide, or a varnish of a diisocyanate-modified, BPDA-modified, or sulfone-modified resin of these can be used. The thermosetting resin binds the solid lubricant, exhibits the conformability by being scraped by the shaft, and is extremely stable against corrosion.

In the present invention, the composition of the aluminum bearing alloy is not particularly limited, but preferably 10% by weight or less of Cr, Si, Mn, Sb, Sr, Fe, Ni, M.
o, Ti, W, Zr, V, Cu, Mg, Zn, etc. and 2
An alloy containing 0% by weight or less of one or more of Sn, Pb, In, Tl and Bi can be preferably used. The elements of the former group mainly impart strength and wear resistance, and the elements of the latter group mainly impart conformability. It is preferable to use the former and the latter in combination.

The method of forming the coating layer will be described below. After the aluminum-based bearing alloy to be treated is processed into a sliding bearing-shaped lining, it is degreased in an alkaline treatment liquid such as caustic soda, followed by washing with water and hot water to remove the alkali adhering to the surface. The surface roughness is adjusted under the conditions of lining and alkali treatment.
After washing with hot water and drying with warm air, apply a solid lubricant and resin diluted with a suitable diluent onto the lining by spraying, and 150 to 3
Dry and bake at 00 ° C. When the surface roughness after film formation is rough, smoothing treatment with a puff or the like is performed. In addition to the spray method, the coating can be formed by a method such as a tumbling method, a dipping method, a brush coating method and a printing method. As disclosed in Japanese Patent Laid-Open No. 4-78319 of the present applicant,
The coating layer may be formed of two or more layers made of different materials.

[0013]

[Function] Conventionally, a coating layer in which a solid lubricant is bonded with a resin is softer than an aluminum-based bearing alloy, so it is thought that it has excellent conformability and quickly brings about a fluid lubrication state. The following was found. (A) The conformability becomes better when there is more solid lubricant in the coating layer. (B) The thicker the coating layer is, the more wear it causes, and the more wear that is required to fit in the product. As a result, the bearing surface becomes concentric with the mating shaft, and the seizure resistance deteriorates. FIG. 2 shows M
A coating layer comprising 85% by weight of oS2 and 15% by weight of PAI (polyamideimide) and having a surface roughness of 2.5 μmRz shows that the seizure resistance is lowered when the film thickness exceeds about 5 μm. (C) As the coating layer becomes thinner, its surface roughness tends to reproduce the roughness of the underlying aluminum-based bearing alloy. A thin coating layer that reproduces the surface roughness is not very compatible. As a result, fluid lubrication is hindered, and the sliding characteristics are worse than that of an aluminum-based bearing alloy without a coating layer. FIG. 3 shows that the seizure resistance decreases with the surface roughness Rz of the coating layer having the same composition as in FIG. 2 and having a film thickness of 5 μm. The present invention, based on these findings, provides a technique for thinning the coating layer and controlling the roughness of the underlayer and the coating layer. Hereinafter, the present invention will be described in detail with reference to examples.

[0014]

EXAMPLE FIG. 1 is composed of a back metal (SPCC, steel plate having a thickness of 1.2 mm) 1 and an aluminum bearing alloy (Al-12Sn-1.8Pb-1.0Cu-3.0Si-0.3Cr) 2 having a thickness of 0.3 mm. It is the lining that is done. The surface roughness of the aluminum bearing alloy 2 is shown in Table 1. After forming the coating layer 3 whose composition and thickness are shown in Table 1, the surface roughness shown in Table 1 was obtained by buffing. The sliding property test method was as follows.

Seizure resistance test Tester: Static load bearing tester Rotation speed: 1000 rpm Oil temperature: 140 ° C. Oil type: 7.5 W-30 Load: Increase by 10 MPa every 30 minutes.

Abrasion test Tester: Dynamic load bearing tester Rotational speed: 2000 rpm Oil temperature: 140 ° C. Oil type: 7.5 W-30 Load: 5 ton compression, 1 ton pull time: 2 Hr

[0017]

[Table 1] Specimen MoS2 amount Bonded resin Undercoating layer Baking amount Amount Type Mixing amount Roughness Thickness Roughness Surface pressure (Wt%) (wt%) (μm) (μm) (μm) (MPa) (μm) 1 * 70 PAI 30 5 20 6 20 30 85 85 PAI 15 2.5 5 5 2.5 90 90 4 3 96 PAI 5 2.5 5 2.5 90 90 7 4 55 PAI 45 2.5 5 5 2.5 50 50 3 5 85 PAI 15 2.5 2.5 10 2.5 50 9 6 85 PAI 15 1.0 2 1.0 50 2 7 85 PAI 15 4.3 5 4.3 4.3 50 3 8 85 PAI 15 1.5 5 1.5 60 5 9 9 85 Epoxy 15 2.5 5 2.5 2.5 80 5 10 85 Phenol 15 2.5 2.5 5 2.5 70 4 11 * 70 PAI 30 6 5 7 30 6 12 * --- 4.5-4.5 30 2 13 * 45 PAI 55 2.5 2.5 5 2.5 20 4 14 * 100--4.5 5 5 30 8

Sample No. 1 in Table 1 has a film thickness of the coating layer larger than the range of the present invention, and also Sample No. 11
Is a comparative example in which the surface roughness is rougher than the range of the present invention, and further, the sample number 12 is not provided with a coating layer, and therefore the sliding characteristics are not excellent. Sample 13 is a comparative example with low seizure resistance because sample 13 has less solid lubricant and more resin, and sample 14 has no resin. On the other hand, it is clear that the sliding bearing material of the present invention has a high seizure load and a small amount of wear. In particular, the combination of MoS2 and PAI (polyamideimide) achieves excellent sliding characteristics.

[0019]

As described above, according to the present invention, it is possible to improve the seizure resistance and wear resistance of the coating layer, and therefore to provide a material having excellent sliding characteristics as a sliding bearing of an internal combustion engine. You can

[Brief description of drawings]

FIG. 1 is a conceptual view of a cross section of a sliding bearing material.

FIG. 2 is a graph showing the relationship between the film thickness (μm) of a coating layer and seizure resistance.

FIG. 3 is a graph showing the relationship between the surface roughness (Rz, μm) of the coating layer and seizure resistance.

[Explanation of symbols]

 1 Back metal 2 Aluminum bearing alloy 3 Coating layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Haraguchi 3-65 Midorigaoka, Toyota-shi, Aichi Otoyo Kogyo Co., Ltd. (72) Hirofumi Michioka, 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Yoshio Fuwa, Toyota-cho, Toyota City, Aichi Prefecture, Toyota Toyota Motor Corporation

Claims (3)

[Claims] 1. Surface roughness of 1.0 μm or more to 4.5 μm
The surface of the aluminum-based bearing alloy in the range of less than Rz is composed of 98 to 55% by weight of a solid lubricant and 2 to 45% by weight of a thermosetting resin, and has a film thickness of 2 to 10 μm and a surface roughness of 5 μm Rz or less. A sliding bearing material characterized in that a coating layer is provided. 2. The solid lubricant is MoS2, WS2B
The sliding bearing material according to claim 1, which is at least one selected from the group consisting of N and graphite. 3. The sliding bearing material according to claim 1, wherein the thermosetting resin is at least one selected from the group consisting of polyimide, epoxy and phenol resins.