JP2003269456A - Slide material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve corrosion resistance under a high temperature condition, in a slide material using a Cu alloy. <P>SOLUTION: The slide material of the Cu alloy is generally manufactured by sintering. However, this inventor finds the fact that, if adding hard grains to an Cu-Sn-Ni alloy, the growth of crystal grains is suppressed at a final sintering process to make fine crystalline alloy. Fining of the crystal grains improves strength, provides excellent fatigue resistance, and especially has the effect on preventing corrosion due to lubricating oil. The slide material contains 0.5 to 15% by mass of Sn, 2 to 0.2 to 10% by mass of Ni, and 0.4 to 10% by mass of hard grain, and a rest part is actually made from Cu. The hard grain is made from one or more selected from WC, W<SB>2</SB>C, Mo<SB>2</SB>C, W, and Mo, and the average cross sectional area of the crystal grain of a matrix of Cu-Sn-Ni is made to be not more than 0.07 mm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding material made of a Cu-based alloy, and more particularly to a sliding material having excellent corrosion resistance and fatigue resistance.

[0002]

Conventionally, Cu-Sn-Pb alloy bearings are bushes as sliding materials for Cu alloys.
Used in thrust washers, etc. However,
A bearing used in a high temperature environment, such as a piston bush used for a small end of a connecting rod, has a problem of corrosion due to lubricating oil and a problem of fatigue resistance against a large load change. In order to improve this, it has been attempted to improve corrosion resistance and fatigue resistance by using Cu-Sn-Ni-based or Cu-Sn-Ni-Pb-based materials to which Ni is added without reducing or using Pb. There is. However, recent piston bushes for internal combustion engines are increasingly used in high temperature environments, and such improvements have not completely solved the problem of corrosion.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a sliding material using a Cu-based alloy, which is excellent in corrosion resistance and fatigue resistance.

[0004]

The sliding material of a Cu-based alloy is generally manufactured by sintering.
-Sn-Ni alloy for certain hard particles _{(WC, W} 2 _C,
It has been found that the addition of (Mo ₂ C, W, Mo particles) suppresses the growth of crystal grains during the final sintering step, resulting in a fine crystal alloy. And by the refinement of crystal grains,
It has been found that the strength is improved, the fatigue resistance is excellent, and in particular, it is effective in preventing corrosion due to lubricating oil.

Therefore, according to the present invention, Sn is 0.5 to 15% by mass, Ni is 0.2 to 10% by mass, hard particles are 0.4 to 10% by volume, and the balance is substantially Cu.
One or more selected from C, W ₂ C, Mo ₂ C, W and Mo are used, and the crystal grain size of the Cu—Sn—Ni alloy matrix is 0.070 mm or less ( Claim 1). The size of this crystal grain is JIS H
0501 According to the grain size test method for copper alloy products.

The average particle diameter of the hard particles in this case is WC,
W ₂ C and Mo ₂ C are 0.1 to 10 μm, and W and Mo are 1 to 2
It is preferably 5 μm (claim 2). Further, the present invention provides a total amount of 40% by mass or less of Fe, Al, Mn and C.
One or more of o, Zn, Si and P can be contained (claim 3). Furthermore, the present invention provides a total amount of MoS of 10% by volume or less.
₂ , WS ₂ , h-BN, and graphite may be included in one or more kinds (claim 4). Further, the total amount of Bi and / or Pb may be 10% by mass or less (claim 5).

The reason for the above limitation will be described. (1) Sn: 0.5 to 15 mass% Sn strengthens the Cu alloy matrix and improves fatigue resistance. If it is less than 0.5% by mass, there is no effect of improving the strength of the Cu alloy matrix, and if it exceeds 15% by mass, Cu-Sn
Many compounds are formed and become brittle. (2) Ni: 0.2 to 10 mass% Ni dissolves in the Cu-based alloy matrix to improve the corrosion resistance of the Cu-based alloy matrix. In addition, it strengthens the matrix and improves fatigue resistance. If it is less than 0.2% by mass, the effect of improving the corrosion resistance of the Cu-based alloy matrix and the effect of improving the strength cannot be obtained. If it exceeds 10% by mass, the Cu-based alloy matrix becomes too hard, which is not preferable as a sliding material.

(3) Hard particles: WC, W ₂ C, Mo ₂ C, W, Mo Since these hard particles have good wettability with the Cu alloy matrix, the alloy strength does not decrease, and there are Since it does not occur, it prevents penetration of the lubricating oil into the Cu alloy matrix and improves the corrosion resistance. (4) Hard particles: 0.4 to 10% by volume If the proportion of hard particles is less than 0.4% by volume, there is no effect of refining the crystal grains of the Cu alloy matrix, and as a result,
The effect of improving corrosion resistance cannot be obtained. When it exceeds 10% by volume,
The aggressiveness to the mating material becomes too strong, and the non-seizure property is poor. (5) Crystal grain size of Cu-Sn-Ni alloy matrix: 0.070 mm or less If the crystal grain size of Cu-Sn-Ni alloy matrix (Cu alloy matrix) exceeds 0.070 mm, Therefore, the effect of improving corrosion resistance cannot be obtained.

(6) Size of hard particles WC, W ₂ C and Mo ₂ C: 0.1 to 10 μm WC, W ₂ C and Mo ₂ C are too fine when the hard particles are too small and crystallize. The effect of refining grains is poor, and the effect of improving corrosion resistance cannot be obtained. On the other hand, when it exceeds 10 μm, the aggressiveness to the mating material becomes too strong, and the non-seizure property becomes poor. Further, the state of uniform dispersion is lost, and the effect of refining the crystal grains is reduced.

(7) Size of hard particles W and Mo: 1 to 25 μm W and Mo are less than 1 μm, the hard particles are too fine and the effect of refining crystal grains is poor, and the effect of improving corrosion resistance is obtained. Absent. On the other hand, when it exceeds 25 μm, the aggressiveness to the mating material becomes too strong and the non-seizure property becomes poor. Further, the state of uniform dispersion is lost, and the effect of refining the crystal grains is reduced.

(8) Fe, Al, Mn, Co, Zn, S
i, P: 40 mass% or less in total amount These strengthen the Cu alloy matrix and improve fatigue resistance. When it exceeds 40% by mass, it does not contribute to the improvement of fatigue resistance.

(9) MoS ₂ , WS ₂ , h-BN, graphite: 10% by volume or less in total amount These are solid lubricants, and their addition is non-seizure resistance.
The wear resistance can be further improved. If the total amount exceeds 10% by volume, the strength decreases.

(10) Bi, Pb: 10% by mass or less in total amount These are dispersed in a Cu alloy matrix to form a soft phase, which improves foreign matter embeddability and non-seizure property. If it exceeds 10% by mass, the strength of the Cu alloy matrix decreases.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a bush for a piston pin provided at a small end portion of a connecting rod will be described below. Bush for piston pin 1
Is configured as a so-called wound bush, and as shown in FIG. 1, as a sliding material according to the present invention, a Cu plating layer 3 for enhancing adhesiveness is provided on an inner peripheral surface of a backing metal 2 made of a thin steel plate. Bearing alloy layer 4 is deposited.

The bearing alloy layer 4 is made of a Cu-based sintered alloy and has the component composition described in the claims as represented by Examples 1 to 11 described later. That is, the bearing alloy layer 4 has a Sn content of 0.5 to 15
% By mass, Ni 0.2-10% by mass, hard particles 0.4-1
0% by volume, the balance consisting essentially of Cu. The hard particles are made of one or more selected from WC, W ₂ C, Mo ₂ C, W and Mo, and the size of the crystal grains of the Cu-Sn-Ni matrix is 0.070 mm or less. is there.

In this case, the hard particles WC, W_TwoC, Mo_Two
The average particle size of C is 0.1 to 10 μm, and W and Mo are 1 to 25 μm.
It is preferably m. In addition, Fe, Al, Mn, C
40 kinds in total of at least one of o, Zn, Si and P
% Or less, and Bi and / or Pb may be included.
MoS may be contained in a total amount of 10% by mass or less._Two, W
S _Two, H-BN, graphite at least one type with a total volume of 10 volumes
The product% or less may be included.

Here, a method for manufacturing the bush 1 will be briefly described. First, a Cu alloy powder having a predetermined component and hard particles are mixed with a mixer so that a predetermined ratio is obtained. Cu alloy powder is Cu-Sn-Ni alloy, Cu-Sn-Ni-
Zn alloy or the like is used. In this mixing process, Cu
The alloy powder has 90% or more of 75 μm or less and 45 μm or less in order to uniformly mix with the hard particles.
A powder having m or less of 60% or more was used.

Next, the powder mixed as described above is sprinkled on a 1.3 mm thick strip steel plate (back metal 2) to which the Cu plating layer 3 has been applied in advance, and the powder is mixed at 800 to 950 ° C. in a reducing atmosphere.
Then, the first sintering is performed for about 15 minutes, and then the rolling is performed for the densification of the bearing alloy layer. Further, sintering and roll rolling were repeated for densification of the bearing alloy layer to obtain a bimetal having a total thickness of about 1.6 mm and a bearing alloy layer thickness of about 0.4 mm.

In the manufacturing process of this bimetal, the sintering temperature in the last sintering step was set to 920 ° C. or lower in order to suppress the growth of crystal grains. This temperature of 920 ° C. or lower is a temperature at which a liquid phase does not occur in the Cu—Sn—Ni-based matrix. The sample of Comparative Example 3 in the test described below was performed at a final sintering temperature of 970 ° C. afterwards,
The bimetal is machined into a cylindrical shape and finally the overlay layer 5 is applied to manufacture the bush 1.

In order to confirm the effect of the product of the present invention, the inventor of the present invention and the product of the comparative example having the compositions shown in Table 1 below measure the size of the crystal grains of the Cu alloy. , A corrosion test, a seizure test, and a fatigue test were performed.

The crystal grain size of the Cu alloy is JIS H
According to 0501, the grain size test method for copper alloy products. Corrosion test is performed from bimetal to total thickness (bearing alloy layer thickness 0.3m
m) A test piece having a size of 1.5 mm, a width of 25 mm, and a length of 50 mm was prepared and carried out in lubricating oil. Seizure test, total thickness (bearing alloy layer thickness 0.3mm) 1.5mm, inner diameter 20mm, width 1
A bush having a diameter of 5 mm was prepared, and the bush was tested.
In addition, the fatigue test is the total thickness (bearing alloy layer thickness 0.3 mm)
A half bearing having a size of 1.5 mm was produced, and the test was performed on a cylindrical bearing obtained by abutting two half bearings. The conditions of each test are as shown in Tables 2-4.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

In the seizure test, the bearing surface pressure is increased by 5 Mp, the bearing back surface temperature exceeds 200 ° C. for 10 minutes for each bearing surface pressure, or the driving current of the motor for driving the rotary shaft is increased. The bearing surface pressure that was one step lower than the bearing surface pressure when an abnormal value was shown was taken as the maximum surface pressure without seizure. In the fatigue test, a fixed load was applied to the half bearing to slide it, and after the test, it was confirmed whether fatigue occurred in the bearing alloy.

As is clear from Table 1, invention products 1 to 11
In comparison with Comparative Examples 1 to 5, is excellent in corrosion resistance, and is equivalent or superior in anti-seizure property and fatigue resistance.

The crystal grain size of the Cu alloy matrix, the constituent elements of the Cu alloy matrix, the type of hard particles and the corrosion resistance will be described below. As is clear from Table 1, the invention products 1 to 11 and the comparative example products 1 to 5 are in agreement where the size of the crystal grains of the Cu alloy matrix is 0.070 mm or less. Inventive products 1 to 11 have a Cu alloy matrix of Cu-S
n-Ni system (Inventive products 1 to 10 are Cu-Sn-Ni, Inventive product 11 is Cu-Sn-Ni-Zn)
o ₂ C, WC, Mo, W are used. On the other hand, Comparative Example Product 1 uses Cu-Sn-Ni as the Cu alloy matrix, but does not contain hard particles. Further, Comparative Examples 2 and 3 use Mo ₂ C as the hard particles, but Ni and Sn are contained in the Cu alloy matrix.
Does not include. Further, the comparative example products 4 and 5 are prepared by adding a Cu alloy matrix to C
u-Sn-Ni, Mo ₂ C as hard particles,
Al ₂ O _{3 and} SiC are used. The invention products 1 to 11 are superior in corrosion resistance to the comparative products 1 to 5. From the above, M in a Cu-Sn-Ni-based Cu alloy matrix with a crystal grain size of 0.070 mm or less
It can be seen that inclusion of o ₂ C, WC, Mo, and W improves the corrosion resistance.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following expansions and modifications are possible. The hard particles may be W ₂ C. The hard particles may contain two or more kinds selected from W ₂ C, Mo ₂ C, WC, Mo and W. The present invention is not limited to the piston pin bush provided on the small end side of the connecting rod, but may be applied to the main bearing of an internal combustion engine configured as a half bearing.

[Brief description of drawings]

FIG. 1 is a sectional view of a bush showing an embodiment of the present invention.

[Explanation of symbols]

1 is a bush, 2 is a back metal, and 4 is a bearing alloy layer (sliding material).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Ishikawa             Daido Metal Works, 2 Sanarucho-cho, Kita-ku, Nagoya-shi             Business (72) Inventor Masaaki Sakamoto             Daido Metal Works, 2 Sanarucho-cho, Kita-ku, Nagoya-shi             Business F term (reference) 3J011 QA03 SB02 SB03 SB04 SB05                       SE01 SE06                 3J033 AA05 AB03 AC01 GA05 GA07

Claims (5)

[Claims] 1. Sn 0.5 to 15% by mass, Ni 0.2 to
10% by mass, 0.4 to 10% by volume of hard particles, and the balance substantially consisting of Cu, and the hard particles are WC, W ₂ C, Mo ₂ C, W and Mo.
Cu-Sn- consisting of one or more selected from
Ni-based crystal grain size is 0.070 mm
The following are sliding materials. 2. The average particle diameter of the hard particles is WC, W ₂
C and Mo ₂ C are 0.1 to 10 μm, and W and Mo are 1
The sliding material according to claim 1, wherein the sliding material has a thickness of -25 μm. 3. The sliding material according to claim 1, wherein the total amount of one or more selected from Fe, Al, Mn, Co, Zn, Si and P is 40 mass% or less. 4. The sliding material according to claim 1, wherein the total amount of one or more selected from MoS ₂ , WS ₂ , h-BN and graphite is 10% by volume or less. 5. The sliding material according to claim 1, which contains Bi and / or Pb in a total amount of 10% by mass or less.