JPH11350008A - Sintered copper alloy sliding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce wear in a sliding material and to improve its seizuring resistance to the mating member by executing sintering in such a manner that tungsten component is granularly scattered into a bronze matrix, furthermore locally projecting a part of the tungsten sintered grains to the side of the mating member to form a rugged sliding face and securing a lubricating oil film by rugged surface. SOLUTION: As for the sliding material, the adoption of a mode of being formed into a high density sintered body, a mode of being formed into a composite material in which a lubricating synthetic resin material is enclosed into a void of a porous low density sintered body and a mode of being into the one having self-lubricity by impregnating the void of the porous low density sintered body with lubricating oil is possible. The content of tungsten component is preferably controlled to 3 to 13 wt.% to the whole alloy material powder. The sliding material 11 forms a sintered alloy layer on a steel sheet back plate 12, and tungsten sintered grains 14 are sintered into a bronze matrix 13 in a granular dispersed state. A part of the tungsten sintered grains locally projects onto the surface 15 of the matrix to form ruggedness on a sliding face 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a sintered alloy layer containing copper as a main component on a back metal plate, and requires various bearings such as a sliding bearing and a rolling bearing and a low friction sliding surface. A sintered copper alloy-based sliding material used for various sliding materials, particularly for solving the problems of a conventional sliding material having a lead bronze or other copper alloy-based sintered alloy layer. .

[0002]

2. Description of the Related Art In a copper alloy type sliding material of this kind, a lubricating component is contained in a copper (Cu) -tin (Sn) matrix for the purpose of imparting conformability to a mating member and preventing seizure. In general, lead bronze (SAE792, SAE794) made of Cu-Sn-Pb as a sintered alloy layer has been used, but the sliding material has the following problems. Was included.

[0003] Since Pb contains a substance that can cause pollution, it must be handled with great care so as not to damage the environment. Since the melting point of Pb is as low as about 300 ° C., when the temperature of the sliding surface is increased due to use at a high temperature or sliding friction, Pb flows out or closes a groove for storing a lubricating oil, thereby causing sliding. There is a risk of burn-in due to deterioration of performance. Since Pb has a problem in corrosion resistance, it is easily attacked by additives contained in the lubricating oil or an organic acid film generated by deterioration of the lubricating oil. Pb has low hardness and affinity (bonding strength) with Cu as a base material
The Pb exposed on the sliding surface effectively functions as a lubricating layer at the initial stage because it is not good. Abnormal friction due to metal contact with the member.

[0004] In addition to lead bronze, molybdenum (Mo), which is one of high melting point metal materials, may be contained, but the difference in hardness from the matrix (bronze) is small and the affinity (bonding strength) is not sufficient. Therefore, it is difficult to maintain the sliding surface in a good sliding state for a long period of time, and there are cases where ceramics such as FeB are further contained, but there are difficulties in workability and hardness is low. There is a danger that the mating member may be damaged because the material is too high, and it has not been possible to find a suitable material having a suitable hardness and a satisfactory affinity (bonding strength) with the matrix (bronze).

[0005]

The present inventor has made various studies and found that an appropriate material which satisfies the conditions of appropriate hardness and good affinity (bonding strength) with the matrix (bronze) is obtained. It has been confirmed that the above-mentioned various problems in the prior art can be solved by incorporating it in a matrix (bronze). A new sintered copper alloy-based sliding material having improved seizure resistance to members has been provided.

[0006]

The sintered copper alloy-based sliding material according to the present invention is characterized in that a tungsten component is scattered in a bronze matrix in a granular manner, and a part of the tungsten sintered grains is partially eliminated. An uneven sliding surface is formed by projecting locally to the mating member side, and a lubricating oil film is secured by the uneven step.

In the above sliding material, the tungsten sintered particles have a high melting point and high hardness, a small friction coefficient, and a high bonding strength with a bronze matrix. On the other hand, even under adverse conditions such as high temperature, high speed rotation, and high load, it is possible to improve the seizure resistance with respect to the mating member with little wear, and to secure a lubricating oil film due to uneven steps even during long-term use. And stable sliding performance can be maintained.

In addition, since lead (Pb) is not contained as a lubricant component in the bronze matrix, the above-mentioned problems of the use of lead have been solved. Tungsten has the same refractory metal material as molybdenum. Since the melting point and the hardness are much higher than the above, especially the bonding strength with the bronze matrix is much higher, the difference between the above-mentioned effects appears remarkably. There is no difference, and the subject matter of the related art is solved, for example, there is no damage to the mating member because it has a suitable conformability, and it is advantageous in terms of workability.

The sliding material may be a high-density sintered body, a porous low-density sintered body may be a composite material in which a lubricating synthetic resin material is sealed in voids, or a porous low-density sintered body. It is possible to adopt a mode of self-lubricating by impregnating the voids of the sintered body with a lubricating oil, and to use the above-mentioned tungsten component by changing the mixing ratio according to the application, the properties of the mating member or the use environment, etc. In this case, it is most preferable to use the powder in the range of 3 to 13% by weight of the whole alloy material powder.

In the case of a high-density sintered body, a sliding material having a high rigidity and a high bonding strength of tungsten sintered grains to a bronze matrix can be obtained. In the case of composite materials, the advantages of a metal material that has good thermal conductivity and can absorb or disperse sliding friction heat and a resin material that can reduce the friction coefficient during low-speed sliding are used, In addition to improving the familiarity with the mating member at the initial stage, it has the effect of preventing seizure if transferred during use. In the case of self-lubrication impregnated with lubricating oil, unlike the former two, lubrication from the outside There is an advantage that it can be used easily without being used and can be manufactured at low cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a sintered copper alloy-based sliding material according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a schematic partial cross-sectional view. The sliding material 11 according to the first embodiment is
A sintered alloy layer is formed thereon, and the sintered alloy layer is made of copper (C
u) -tin (Sn) alloy, that is, a bronze matrix 13, in which tungsten (W) components 14 are interspersed in a granular dispersion state and sintered, and the sintered body has a high density in which internal voids are reduced by rolling. In the sintered body, a part of the interspersed tungsten sintered grains 14 locally protrudes above the matrix surface 15 to form a sliding surface 16 with respect to a mating member (not shown) in an uneven manner.

As for the sliding surface 16 formed by the irregularities formed by the tungsten sintered grains 14, the surface side of the protruding tungsten sintered grains 14 bears the main sliding contact with the mating member, and the concave matrix surface 15 assists. The sliding frictional resistance is reduced and the frictional frictional resistance is reduced and the oil film 17 is formed by the lubricating oil supplied to the step formed between the matrix surface 15 and the step. A stable and good lubrication state can be maintained.

In particular, the sintered alloy layer containing the tungsten sintered grains 14 has a hardness (Vickers 350 to 5) of tungsten (W) not only of lead (Pb) but also of bronze matrix 13.
00) and a high melting point (3410 ° C.) so that they do not wear or melt as easily as lead in lead bronze, and tungsten (W) is
And has a high binding strength, so that it does not fall off due to sliding resistance or the like, and can maintain a sliding state without image sticking or uneven sliding.

Further, when compared with the case where molybdenum (Mo) is contained in the bronze matrix, Mo is not as high in hardness as W (about 200 to 250 Vickers) and has a small difference in hardness from the bronze matrix. As a result, it is difficult to secure the step for forming the oil film over a long period of time, and the bonding strength with the bronze matrix is not high. There is a risk of doing so.

Sliding material 11 of the above-described high-density sintered body
When manufacturing a low-density sintered body, an alloy material powder obtained by mixing a bronze powder and a tungsten powder at a predetermined weight ratio is sprayed on the steel plate backing 12 and sintered in an RX reducing atmosphere. The low-density sintered body is rolled and densified, and then sintered again to form an alloy layer of the high-density sintered body.

When the ratio of the sintered tungsten particles 14 contained in the sliding material 11 is reduced (for example, 1% or less), the number of convex portions of W forming the sliding surface 16 is reduced and the mating member is formed. When the matrix surface 15 is in sliding contact with the surface, seizure or wear occurs. Conversely, when the ratio is increased (for example, 20% or more), the number of convex portions of W increases and the friction coefficient on the sliding surface 16 increases. At the same time, it is difficult to form the oil film 17 by the lubricating oil, and the lubricity is impaired.

Therefore, it is necessary to set the tungsten sintered grains 14 in the sliding material 11 to a desired value that is compatible with the mating member and other conditions of use. Most preferably, it is contained in the range of 3 to 13% by weight with respect to the entire alloy material powder forming the sintered alloy layer.

Next, in the sliding material 21 according to the second embodiment of the present invention, a sintered alloy layer is formed on a steel plate back metal 22 as shown in a schematic partial sectional view of FIG. As in the case of the first sliding material 11, the gold layer is formed by sintering tungsten (W) components 24 in a granular dispersion state in a bronze matrix 23, and this sintered body is porous. Is a low-density sintered body having many internal voids 28 (for example, the porosity is about 50% of the whole).

In the sliding material 21, a part of the tungsten sintered grains 24 scattered locally protrudes locally onto the matrix surface 25, and a sliding surface 26 for a mating member (not shown) is formed with irregularities. As in the case of the first sliding material 11, the surface side of the tungsten sintered grain 24 bears the main sliding contact with the mating member, and the matrix surface 25 assists the sliding contact. Oil slick 2
By forming 7, the sliding frictional resistance is reduced, and a stable and favorable lubricating state is maintained over a long period of time.

Further, a synthetic resin material having lubricity and a small coefficient of friction is encapsulated and integrated into the void 28 formed in the sintered alloy layer, but a composite material of the sintered metal material and the encapsulated resin material is integrated. By using a hard metal material alone, it is difficult to obtain a friction coefficient during low-speed sliding, which is difficult to obtain, and a resin material with poor thermal conductivity alone absorbs sliding friction heat generated on the sliding surface, which is difficult to obtain. The sealing resin material has a good conforming action to the mating member and, when transferred, adheres to the matrix surface 25 or the mating member to prevent seizure.

As the encapsulating resin material, a resin such as a fluororesin, a polyamide resin, a polyacetal resin, a polyimide resin, a phenol resin, a polyphenylene sulfide resin, a polyether ketone resin, or a mixture of a plurality of such resins may be used. Among them, fluorine resin-based polytetrafluoroethylene (PTFE) can be expected to reduce friction coefficient at low speed and improve wear resistance.
In particular, it has been confirmed that it is desirable to use a phenol resin containing PTFE.

In manufacturing the sliding material 21 described above,
An alloy material powder in which bronze powder and tungsten powder are mixed at a predetermined weight ratio is sprayed on the steel backing plate 22 and sintered in an RX reducing atmosphere to produce a porous, low-density sintered alloy layer. A synthetic resin material having lubricity is sealed in the gap 28 formed in the bonding gold layer and integrated, and the cost is reduced by one sintering compared with the first sliding material 11 of high density. Can be manufactured.

Further, as a sliding material (not shown) of the third embodiment according to the present invention, a synthetic resin material is not sealed in the gap 28 of the sliding material 21 of the second embodiment, but a lubricating oil is used instead. Oil-impregnated sliding material pre-impregnated with
As conventionally used, in order to increase the oil content (for example, about 10 to 30% by volume ratio), the thickness of the porous low-density sintered alloy layer is increased and the steel plate back metal 22 is omitted. And a low-density sintered body having a porosity suitable for the oil content.

The oil-containing sliding material is self-lubricating, in which the lubricating oil in the gap oozes out by a pump action to form an oil film on the sliding surface, and is not lubricated from the outside like the sliding materials 11 and 21. In addition to the simplicity that can be used, the abrasion resistance and seizure resistance are improved by the sliding surface formed in irregularities with tungsten sintered grains, but the problem of the strength of the porous matrix and the sliding material Since the fluid lubrication state cannot be obtained and the boundary lubrication state occurs as in 11 and 21, the use at a low speed and a high load requires limited use in consideration of the difficulty.

As a conventional technique, there is a method in which a solid lubricant such as graphite or molybdenum disulfide is mixed into a copper alloy powder and sintered instead of lead (Pb). It is also effective when applied to the sliding material according to the present invention. When the content of the solid lubricant is less than 0.1%, the effect of addition is not obtained. Wear is accelerated.
About 2.5% by weight is desirable.

[0026]

EXAMPLES (Example 1) Apparent density 2.6 g, Sn9.
0%, bronze powder having a particle size of 150 μm or less;
Tungsten (W) powder of 6 to 12 μm is mixed at a predetermined weight ratio, and these alloy material powders are sprayed on the washed steel backing metal, and at a temperature of 860 ° C. in an RX reducing atmosphere.
The first sintering was performed for 30 minutes, and after cooling, the alloy density was increased by roll rolling and finished to a predetermined thickness, and the second sintering was performed under the same conditions as the first sintering. A sintered copper alloy-based sliding material having a total thickness of 1.8 mm including a steel plate back metal having a 0.5 mm thick alloy layer having a width of 150 mm, which increases the degree of bonding of particles and removes strain due to work hardening during rolling. And

Example 2 Apparent density 2.6 g, Sn
A tungsten (W) powder having a particle size of 7.6 to 12 μm is mixed at a predetermined weight ratio with a bronze powder having a particle size of 9.0% and a particle size of 150 μm or less, and these alloy material powders are sprayed on the cleaned steel plate back. 86 in a reducing atmosphere of RX
After sintering at 0 ° C. for 30 minutes, the resulting voids (porosity about 50% of the total)
Impregnated with a phenol resin containing 30% of TFE (polytetrafluoroethylene) and cured, 0.5 mm thick and 1 width
The total thickness including the steel plate back metal on which the 50 mm alloy layer is formed is 1.
An 8 mm sintered copper alloy-based sliding material was used.

In the sliding materials of Examples 1 and 2, the weight ratio of the W powder in the material powder forming the alloy layer was 3%, 6.5% and 13% in Example 1, respectively. In the case of Example 2, it was manufactured in a state of being set to 3%, which was used as Samples 1 to 4 and subjected to a comparison test with Samples 5 to 9 according to the prior art (seizure resistance tests 1 and 2, wear test). The results are as shown in Table 1, and the test conditions are as follows.

[0029]

[Table 1]

(Seizure resistance test 1) Test apparatus: Ring-on-plate type friction and wear machine Load: Increased linearly from 200 N (1 MPa) until friction temperature reaches 200 ° C. or friction force reaches 490 N Speed: 4800 r / min ( 347m / min) Lubricating oil: Light oil (25cc / min) Oil temperature: 80 ° C Mating member: SCM420H (HRC 55-60, surface roughness 1.0S)

(Seizure resistance test 2) Test apparatus: bearing dynamic load tester (see FIG. 3) Number of rotations: 4000 r / m Load: 100 N is accumulated every 5 minutes from 600 N, and the back temperature of the test bush is 200 ° C. Until the frictional force reaches 50 N Bush: $ 55.5 x $ 52 x 10 Mating shaft: Material S45C Hardened and tempered Hardness HR
C58 Surface roughness 0.58a Lubricating oil: SAE30 100-300cc / min
Combined with shower Lubrication temperature 140 ± 10 ℃

(Wear test) Test apparatus: Ring-on-plate type friction and wear machine Load: 200 N (contact pressure: 10 Mpa) Speed: 1000 r / min (72 m / min) Sliding time: 20 Hrs Lubricating oil: Motor oil 30 (25 cc / min) ) Oil temperature: 80 ° C Mating member: SCM420H (HRC 55-60, surface roughness 1.0S)

As is clear from the test results in Table 1, the sintered copper alloy-based sliding material according to the present invention has less seizure and less wear than the conventional sliding material of this type. Less good.

[Brief description of the drawings]

FIG. 1 is a schematic partial cross-sectional view of a sintered copper alloy-based sliding material according to a first embodiment of the present invention using a high-density sintered body.

FIG. 2 is a schematic partial cross-sectional view of a sintered copper alloy-based sliding material according to a second embodiment of the present invention using a composite material of a porous low-density sintered body and a synthetic resin material.

FIG. 3 is a schematic front view of a bearing dynamic load tester used in a seizure resistance test 2.

[Explanation of symbols]

 11,21 Sliding material 12,22 Steel plate back metal 13,23 Bronze matrix 14,24 Tungsten sintered particles 15,25 Matrix surface 16,26 Sliding surface 17,27 Oil film 28 Void

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[Procedure amendment]

[Submission date] June 22, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003] Since Pb is a substance that can cause pollution, it must be handled with great care so as not to damage the environment. Since the melting point of Pb is as low as about 300 ° C., when the temperature of the sliding surface is increased due to use at a high temperature or sliding friction, Pb flows out or closes a groove for storing a lubricating oil, thereby causing sliding. There is a risk of burn-in due to deterioration of performance. Since Pb has a problem in corrosion resistance, it is easily susceptible to additives contained in the lubricating oil or organic acids generated by deterioration of the lubricating oil. Since Pb has low hardness and poor affinity (coupling strength) with Cu as a base material, Pb exposed on the sliding surface effectively functions as a lubricating layer at the initial stage, but is not used during a long period of use. The sliding surface may easily wear or fall off, and the entire sliding surface may come into metallic contact with the mating member and cause abnormal friction.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (5)

[Claims] 1. A bronze matrix in which a tungsten component is scattered in a granular manner and sintered, and a part of the tungsten sintered grains locally protrudes toward a mating member to form an uneven sliding surface. And a lubricating oil film is secured by the uneven steps. 2. The sintered copper alloy-based sliding material according to claim 1, wherein the sliding material is a high-density sintered body. 3. The sintered copper alloy-based sliding material according to claim 1, wherein the sliding material is a composite material in which a lubricating synthetic resin material is sealed in voids of a porous low-density sintered body. . 4. The self-lubricating material according to claim 1, wherein said sliding material is made of a porous low-density sintered body and impregnated with lubricating oil.
3. The sintered copper alloy-based sliding material according to item 1. 5. The sliding material according to claim 1, wherein the tungsten component is 3 to 13% by weight of the whole alloy material powder.