JP3242754B2 - Sliding material and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding material and a method for producing the sliding material.
The present invention relates to a sliding material in which a sintered layer of a copper-based powder is formed on a back metal and the sintered layer is impregnated with a resin, and a method of manufacturing the sliding material. Such a sliding material having a bimetal structure in which a sintered layer is impregnated with a resin is mainly used for a bearing of a manual transmission or an automatic transmission of an automobile.

[0002]

2. Description of the Related Art Such sliding materials are disclosed, for example, in
No. 36856, JP-B-63-37445, JP-A-55-55
-106230, U.S. Pat.No. 4,208,427, 466
Nos. 6787 and 5024882, European Patent 0445577
No. describes the composition of the sliding layer, the manufacturing method, and the like.

FIG. 2 is a schematic view of a sliding material processed into a bush, in which 1 is a backing metal, 2 is a sliding layer in which resin and lead bronze are combined, 3 is an Sn or Zn plating layer, 9 is a plating layer. Is a resin. The plating layer 3 is provided for the purpose of preventing corrosion and improving appearance characteristics. Further, as shown in a partial enlarged view of the sliding layer 2 (FIG. 3), the plating layer 3 does not adhere to the resin 2 but adheres to the lead bronze particles 4.

[0004]

When the above-described bush is used in a transmission, lead bronze is corroded by gear oil, and a gap is formed at the boundary between the lead bronze particles 4 and the resin layer 2. Gear oil penetrates to roughen the structure of the sliding layer and swell the surface, resulting in deterioration of bearing performance.

Accordingly, an object of the present invention is to provide a sliding material having a bimetal structure in which a sintered layer having improved corrosion resistance to corrosive lubricating oil such as gear oil is impregnated with a resin, and a method of manufacturing the same.

[0006]

A sliding material according to the present invention is a sliding material in which a sintered layer of a copper-based powder is formed on a back metal, and a resin is impregnated in gaps between sintered metal particles of the sintered layer. The material is characterized in that the metal particles are made of Zn or Sn on the surface at least on the sliding surface side or a layer containing these metals as a main component and an internal copper-based material. Further, the method of manufacturing the sliding material described above,
In a method of manufacturing a sliding material in which a sintered layer of a copper-based powder is formed on a back metal and the sintered layer is impregnated with a resin, after sintering, plating of Zn metal or Zn-based alloy or Sn metal or Sn-based alloy is performed. Thereafter, the resin is impregnated.

Hereinafter, the configuration of the present invention will be described. As the copper-based powder, known copper-based materials such as pure copper, bronze, lead bronze, and phosphor bronze can be used. As the resin of the resin layer, a fluororesin such as polytetrafluoroethylene,
A known resin used as a sliding material such as a phenol resin and a polyimide resin can be used.

[0008] Sn or Zn provided on the surface of the sintered metal particles, which is a feature of the present invention, has excellent corrosion resistance to oil, and is coated with copper, particularly lead bronze, which has poor corrosion resistance to oil to prevent its corrosion.

FIG. 1A schematically shows the structure of the sliding layer when the sintered metal particles 4 are one layer. The surface side of the sintered metal particles 4 is Sn / Zn or Sn /
The Zn surface layer 6 is formed. FIG. 1B schematically shows the structure of the sliding layer when the sintered metal particles 4 have two layers. The upper surface of the sintered metal particles 4 is a Sn / Zn surface layer 6. Some of the lower sintered metal is Sn / Z
The n surface layer 6 is formed. This surface layer does not slide directly on the mating material, but the material is, for example, (c)-
When cut at (c), it appears on the cross section as shown in FIG. 1 (c), and the corrosion of the sintered metal is reduced, thereby contributing to some extent to improving the corrosion resistance.

The above-mentioned Sn / Zn layer 6 can be formed by sintering a copper-based powder on a backing metal by a usual method and then plating Sn, Zn or these components as a main component. After forming the plating layer, impregnate the resin,
Process into product shapes such as bushes. This Sn / Zn layer 6
Is required to be formed with a small thickness so as to leave a gap for resin impregnation, and a preferable plating thickness for that purpose is 5 to 1
0 μm. The Sn / Zn layer 6 contains these elements as main components, and if necessary, contains Cu, Pb, Ni, Bi, Sb.
And the like may be contained.

When the material is cut to form a bush, the sintered powder particles are cut, and the nucleus surrounded by the plating layer, ie, the copper-based material is exposed, and corrosion occurs due to reaction with the oil. Such a bush has a poor corrosion resistance at the cut portion as compared with the sliding surface side. Therefore, as a countermeasure, a heat diffusion treatment is performed after plating to form the diffusion layer 7 as shown in FIG. Is preferred. If the diffusion is carried out simultaneously with the firing of the resin, the number of steps can be reduced, so that the temperature is preferably around 400 ° C. When the diffusion is performed, the Zn / Sn layer 6 formed on the surface by plating becomes an extremely thin layer, but it is preferable that the Sn / Zn layer 6 after the diffusion leave at least about 0.5 μm from the viewpoint of sulfur corrosion resistance. .

[0012]

It is believed that the copper powder of the bimetallic sliding material is corroded by the gear oil due to the S compound added to the gear oil to improve the sliding characteristics. On the other hand, it has been considered to change the above-mentioned copper-based powder to another material having excellent corrosion resistance to S. However, at present, there is no material having both sinterability, sliding characteristics and corrosion resistance.
Therefore, in the present invention, the surfaces of the copper-based sintered metal particles are coated with Zn, Sn, or the like, which has high resistance to corrosion by S and excellent adhesion to Cu of the sintered metal.

Further, as a coating method, a plating method excellent in productivity is adopted. However, in the plating method, Zn and Sn can exist only on the surface, and C
u is the main component, and when the material is cut, the Cu-rich surface is exposed and corrosion occurs from the cross section of the bush,
As a countermeasure, Zn and Cu are also enriched inside the particles by diffusion. Hereinafter, the present invention will be described in detail with reference to examples.

[0014]

EXAMPLE A steel plate having a thickness of 1.0 mm (SPC
Using C), one or two layers of lead bronze (JIS LBC3) powder having a particle size of 80 to 145 mesh were sprayed on the surface, pressed lightly, and then sintered at 800 ° C. for 13 minutes.

Thereafter, plating was performed using the following Zn plating bath. The composition of the plating bath was 40 g / L of zinc oxide, 73 g / L of sodium cyanide, 12 g / L of caustic soda, M ratio of 2.2.
7, or 60 g / L zinc blue, 23 g sodium cyanide /
L, caustic soda 52 g / L, M ratio 2.17. The current density was 2-3 A / dm @ 2 and the bath temperature was 40-50 DEG C. As a result, a plating layer having a thickness of 5 to 10 μm was formed. Some samples were subjected to a diffusion treatment at 400 ° C. for 0.5 hour.

Subsequently, a polytetrafluoroethylene resin was impregnated with a thickness of 20 to 50 μm, baked, and further processed into a bush shape to obtain a test piece.

The bimetal material with backing metal prepared as described above is cut into a rectangular sample having a length of 20 × 30 mm.
It was immersed in a commercially available gear oil to observe the state of CuS formation on the surface. Observation with a microscope of 50 magnifications shows that the case where no CuS was formed was good (○), the case where CuS was formed up to the bronze layer was bad (×), and the middle of these was passed (△), and the following table is shown.

[0018]

[Table 1] Immersion time (hr) 20 40 60 80 No Zn plating (Comparative example) × × × × Zn plating (Example) ○ △ × × Zn plating + thermal diffusion (Example) ○ ○ ○ ○

From the results shown in Table 1, it is clear that Zn plating and subsequent thermal diffusion are effective in improving corrosion resistance.

Example 2 The test piece prepared in Example 1 without Zn plating and the test piece of Zn plating + heat diffusion were immersed in the gear oil used in Example 1 for up to 200 hours and vibrated (30G, 200H).
After giving r), it was subjected to a shaft sliding test shown in FIG. In FIG. 4, 10 is a bush, 11 is a shaft that moves in the axial direction, and 12 is a holding ring. Shaft 11
FIG. 5 shows a result obtained by determining a load when the shaft 11 is advanced by pushing the shaft 11 as a sliding load. From FIG. 5, it can be seen that the sliding load increases as the immersion time increases in the test piece without Zn plating, whereas the sliding load is almost constant in the test piece of the present invention.

Further, FIG. 6 shows the result of measuring the inner diameter and outer diameter of the above-mentioned bush-shaped test piece and determining the difference as an oil clearance. From FIG. 6, it can be seen that the oil clearance decreases as the immersion time increases in the test piece without Zn plating, whereas the oil clearance in the test piece of the present invention is almost constant.

[0022]

As described above, according to the present invention, in a bearing having a bimetal structure in which a sintered metal impregnated with a resin is used as a sliding layer, the corrosion resistance of the sintered metal is improved.
The sliding characteristics are improved and the oil clearance is kept stable, contributing to the improvement of the transmission performance.
Even when a large amount of the compound is added, the performance of the bearing can be stably maintained. In addition, the plating (see 3 in FIG. 2), which has been conventionally performed by bushing, can be omitted, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a sliding layer of the material of the present invention.

FIG. 2 is a schematic sectional view of a bush.

FIG. 3 is an explanatory diagram of corrosion occurring in a conventional sliding layer.

FIG. 4 is an explanatory diagram of a shaft load test method.

FIG. 5 is a graph showing a measurement result of a sliding load.

FIG. 6 is a graph showing measurement results of oil clearance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Backing metal 2 Sliding layer 3 Plating layer 4 Sintered metal 6 Sn / Zn layer 9 Resin 10 Bush

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B22F 7/04 B22F 7/00

Claims (3)

(57) [Claims] 1. A sintered layer of copper-based powder is formed on a back metal,
In a sliding material in which the resin is impregnated in the gaps between the sintered metal particles of the sintered layer, the metal particles are made of Zn or Sn on the surface at least on the sliding surface side, or these metals are the main components. A sliding material comprising a layer to be formed and an internal copper-based material. 2. A method for producing a sliding material, comprising forming a sintered layer of a copper-based powder on a backing metal and impregnating a resin into gaps between sintered metal particles of the sintered layer. Alternatively, a method for producing a sliding material, comprising plating an Sn-based alloy and then impregnating the resin. 3. The method for producing a sliding material according to claim 2, wherein a heat diffusion treatment of the plating layer and the sintered metal is performed after the plating.