JP3274261B2 - Copper-based sliding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper-based sliding material, and more particularly to a copper-based sliding material which can be used in place of a conventional kelmet material.

[0002]

2. Description of the Related Art Kermet, which is a typical example of a copper-based sliding material, is used for engine parts by applying an overlay made of a soft metal or a resin. However, when the overlay disappears, the base kelmet is exposed and printed. Is more likely to occur.
In a bushing kelmet used without an overlay, seizure easily occurs when an oil film breaks. However, Pb particles contained in kelmet are stretched by the mating shaft to form a soft film on the sliding surface, and have the effect of preventing seizure. In fact, it is not enough.

[0003] Therefore, in order to improve the seizure resistance of conventional kelmet, an element which strengthens the Cu matrix such as P or Al is added, Bi or the like which has excellent conformability is added, and seizure resistance of graphite or the like is added. Proposals have been made to add an improving component, to add a wear-resistant component such as alumina, and to use a resin-impregnated sintered material impregnated with a resin, and have achieved some results.

[0004]

Since conventional kelmet is an alloy containing lead in the range of about 20 to 40% by weight, it is important to take measures against lead pollution during melting and sintering. More attention was needed than alloys. Conventionally, it has been thought that unless such a large amount of lead is contained, it is impossible to prevent copper metal from adhering to the counterpart material, and the addition of a small amount of alloying element satisfies the seizure resistance required for practical use. No copper-based sliding material was found. Therefore, an object of the present invention is first to provide a copper-based sliding material that can be practically used as a sliding member and has few added elements. Second, the present invention can be applied to various conventional copper-based sliding material compositions, and an object of the present invention is to provide a copper-based sliding material having a composition capable of suppressing adhesion and further enhancing sliding performance. And

[0005]

SUMMARY OF THE INVENTION The present invention has been studied to improve the seizure resistance of copper-based sliding materials from the above-mentioned viewpoints. It has been completed by discovering that it is concentrated on the surface of the steel to dramatically improve the seizure resistance.

That is, the first aspect of the present invention is that the percentage by weight is 0.1 to 5% (hereinafter, "%" means "% by weight" unless otherwise specified).
Ag) and 0.001-1% S
The present invention relates to a copper-based sliding material having a composition close to pure copper, the balance being substantially composed of Cu and unavoidable impurities.
n, P of 0.5% or less, Al of 5% or less, S of 1% or less
i, Mn of 5% or less, Cr of 5% or less, Ni of 5% or less
And a copper-based sliding material containing one or more Cu matrix reinforcing elements selected from the group consisting of Zn and 30% or less. The third aspect of the present invention relates to a first or second component. And Pb and B of 30% or less, respectively.
The fourth aspect of the present invention relates to a copper-based sliding material containing one or two kinds of anti-adhesion elements selected from the group consisting of i, i. The fifth aspect of the present invention relates to a copper-based sliding material further containing one or more kinds selected from the group consisting of graphite, MoS2 and WS2 each having a percentage of not more than 20%. In addition to any of the components, Al2 O3, SiO2, Si3 N4 of not more than 20% by volume in total.
, Fe3 P, FeB, NiB, BN and SiC, a copper-based sliding material further containing one or more selected from the group consisting of a material having any one of the above-mentioned compositions. Is a sintered material sintered on the back metal, a copper-based sliding material in which the sintered pores are impregnated with a resin, the seventh of the present invention, in addition to the resin is impregnated in the sintered pores The present invention relates to a copper-based sliding material that covers the surface of a sintered material.

Hereinafter, the configuration of the present invention will be described. Ag, which is an additive component common to the first to seventh aspects of the present invention, partially forms a fine eutectic structure, and partly uniformly dissolves in a Cu matrix. On the other hand, S hardly forms a solid solution in Cu and exists as copper sulfide. That is, the basic structure of the material of the present invention is a three-phase structure of a Cu phase in which Ag is dissolved, an Ag rich phase, and copper sulfide. As described above, when the sliding condition of the sliding material in which Ag and S coexist is shifted from fluid lubrication to boundary lubrication and becomes a lubricating state in which seizure is easy, a concentrated layer of Ag and S is formed on the sliding surface by heat due to friction. It turned out to be.

FIG. 1 shows the surface of the material of the present invention after sliding by SIM.
S (SecondaryIon Mass Spectrosco
FIG. 4 is a sketch of a photograph in which Ag is analyzed by the py) method, in which a region where Ag is concentrated on the circular analysis surface is indicated by spots. FIG. 2 is a diagram showing spots of the S-enriched region where the same surface as that of FIG. 1 is detected by the SIMS method. These spot regions almost coincided, and it was confirmed that Ag and S were concentrated at the same site of the test material.

[0009] In such a concentrated layer, Ag and S are significantly higher than in the Cu matrix and can be easily detected by analysis. Since this concentrated layer is very thin, it is difficult to identify the substance, but it is considered that silver sulfide is generated.

[0010] The Ag-S concentrated layer directly contacts the bearing and the partner shaft in a microscopic manner without passing through an oil film, causing friction. Since this part is a place where seizure is likely to occur, the part where the Ag-S concentrated layer is formed coincides with the sliding part where seizure occurs easily. After the Ag-S enriched layer is formed at a position where the bearing and the shaft are in contact, the Ag-S concentrated layer is thinly extended on the sliding surface due to the relative motion between the shaft and the bearing. As a result, adhesion between the bearing and the shaft is suppressed, and seizure resistance is improved. Then, the sliding surface of the bearing on which the Ag-S enriched layer is formed conforms to the mating shaft without causing cohesion, and the lubrication condition at that portion shifts from boundary lubrication to fluid lubrication. Subsequently, the temperature of the part is lowered, and thereafter, the formation of a further Ag-S concentrated layer is suppressed. If seizure is likely to occur in a place different from the above-mentioned part, an Ag-S concentrated layer silver sulfide film is formed in that part. As described above, silver sulfide is locally generated at an arbitrary site where seizure is likely to occur, and is hardly generated at a site where seizure does not occur. It should be noted that the Ag-S concentrated layer is formed and the seizure can be prevented in the same manner as described above even under the sliding condition close to the dry condition where the lubricating oil is small. It is necessary to use a sliding material according to the sixth.

In the copper-based sliding material of the present invention, Ag is 0.1.
If the content is less than 1% by weight and the content of S is less than 0.001% by weight, Cu directly contacts and slides with the counterpart material under boundary lubrication conditions, so that adhesion is likely to occur. On the other hand, if Ag exceeds 5% by weight, the copper alloy becomes hard and becomes unsuitable as a sliding material, and if S exceeds 1% by weight, a large amount of copper sulfide is generated to make the copper material brittle. Therefore, in the present invention, Ag and S need to be within the above ranges. The preferred Ag content is 0.1.
2 to 3.0% by weight, more preferably 0.5 to 1.0% by weight.
5% by weight. The preferred S content is 0.01 to
0.5% by weight, more preferably 0.01 to 0.1%.
0% by weight. The balance of the above composition is impurities usually contained in copper such as Fe and O. The purity of copper is rod copper, electric copper,
Any of electrorefined copper, OFHC and the like may be used.

In the second embodiment of the present invention, S added to copper
n, P, Al, Si, Mn, Cr, Ni and Zn are Cu
It is an element that strengthens the matrix, and seizure resistance and wear resistance can be improved by matrix reinforcement. Even if these elements are added, an Ag-S enriched layer is formed and seizure resistance is enhanced. Sn 20%, P 0.5%, Al 5%, Si 1%, Mn 5%, Cr
When the content exceeds 5%, the content of Ni exceeds 5%, and the content of Zn exceeds 30%, the ductility of Cu is impaired. The preferred content is Sn of 1 to 10%, P
Is 0.2-0.4%, Al is 1-3%, Si is 0.1-
0.5%, Mn is 1-3%, Cr is 1-3%, Ni is 1
３3%, Zn is 15１５20%.

[0013] Pb and Bi added in the third aspect of the present invention are elements that improve conformability and foreign matter burying property. Since these elements are present as secondary phase particles in the Cu matrix, the effect of these elements appears as soon as the overlay is locally lost and the bearing comes into contact with the shaft, but preferentially in areas where adhesion is likely to occur. It doesn't exist. On the other hand, since the Ag-S concentrated layer of the present invention is formed by a reaction using heat as a driving force after the temperature is considerably increased by sliding, its effect does not appear immediately, but priority is given to a place where adhesion is likely to occur. Is formed. Therefore, Pb or Bi, S
When Ag and Ag coexist, excellent sliding performance is realized from the initial use of the bearing until a considerable time has passed after use. In addition, both Ag-Pb and Ag-Bi binary alloys make a eutectic phase diagram having a eutectic point on the Ag low concentration side. When the amount of Ag added is about 0.1% by weight or more, even in practical alloys, Ag is present in these eutectics, but when analysis is performed on a site where adhesion is likely to occur, Ag is not concentrated to the eutectic, and the eutectic structure It is enriched with S over a much larger area.

The graphite added in the fourth aspect of the present invention is a solid lubricant, and is mainly added to the sintered copper alloy in order to prevent seizure by a lubricating action. The fourth feature of the present invention is that seizure is prevented by the action of the solid lubricant and the action of the Ag-S concentrated layer. If the amount of the solid lubricant exceeds 20% by volume, the strength of the sintered alloy decreases. The preferred addition amount is 10 to 18% by volume.

Al 2 O added in the fifth aspect of the present invention
3, SiO2, Si3 N4, Fe3 P, FeB, Ni
B, BN and / or SiC are all hard materials and enhance wear resistance. The fifth feature of the present invention is that seizure is prevented by the wear resistance effect of the hard material and the effect of the silver sulfide film. If the amount of the hard material exceeds 20% by volume, the strength of the sintered alloy decreases. The preferred addition amount is 5 to 12% by volume.

When the copper-based sliding material of the present invention is used as a sintered material, it is preferable to impregnate the sintered pores with a resin. As the impregnated resin, any resin used as a sliding material can be used.
I, PEI, PEEK, aromatic PA, phenolic resin,
Epoxy resin, PTFE, and fluorine resin (PFA,
ETFE, FEP) can be preferably used. The amount of the resin is preferably 30 to 80% by volume, and more preferably 40 to 60% by volume. The porosity of the sintered material is preferably 80 to 30% by volume. Further, the content is more preferably 60 to 40% by volume. A solid lubricant, an anti-wear additive, and the like can be mixed in the impregnated resin. These are specifically graphite, PTF
E, Pb, Pb-Sn alloy, carbon fluoride, P fluoride
b, solid lubricants such as Al2 O3, SiO2, Si3 N
4, wear-resistant additives such as clay, talc, TiO2, mullite, calcium carbide, Zn, etc., inorganic fibers such as glass fiber, carbon fiber, potassium titanate fiber, organic fibers such as aromatic PA, and whiskers such as SiC whisker. ,
Metal fibers such as Cu fibers and stainless fibers. Furthermore, a sliding material used under dry conditions in which the surface of the sintered material is coated with the above impregnated resin can be obtained. When the surface coating resin disappears and the sintered material is exposed, A
The g-S concentrated layer exerts the effect of preventing seizure.

[0017]

As described above, the sliding material of the present invention has a Ag-
Since the S-enriched layer is formed at a site where seizure is likely to occur and when it is likely to occur, practical sliding performance can be exhibited even with a composition close to pure copper having a very small content of Ag and S. It was also surprisingly found that under high load and high peripheral speed sliding conditions, the Cu-Ag-S-based alloy exhibited seizure resistance exceeding kermet.

Since the above-mentioned ternary copper alloy has insufficient abrasion resistance, as a measure for improving the abrasion resistance, measures such as adding a hard material or a matrix strengthening element and strengthening the Cu matrix become effective. . Further, when low friction characteristics are important, measures to add graphite or the like are effective. Furthermore, when initial conformability is important, Pb
It is effective to add such a measure. These measures can be used together.

Further, since the sintered bearing impregnated with resin is used under the condition that the lubricating oil is small, and the sintered bearing coated with the resin is used under the condition without lubricating oil, the area of the exposed sintered layer is reduced during sliding. When it increases slightly, it often burns at once. As a countermeasure, the addition of Ag and S according to the present invention is very effective. In addition to this countermeasure, it is effective to use various countermeasures such as the improvement in wear resistance described in the preceding paragraph. Hereinafter, the present invention will be described in more detail with reference to examples.

[0020]

【Example】

Example 1 An alloy in which Ag and S were added to electrolytic copper so as to have the amounts shown in Table 1 was melted in a high-frequency furnace to prepare a test piece, and the friction coefficient was measured under the following conditions. Testing machine: Bowden-Taber type stick-slip testing machine Sliding speed: 0.06 mm / s Lubrication: One layer of base oil applied Load: 500 g Oil temperature: 22 ° C Opposite material: SUJ2 (8 mm diameter sphere) The area of the deposited Cu (μm2
).

[0021]

Table 1 Composition (%) Rub Test Results Ag S Cu Friction Coefficient Friction Coefficient Fluctuation Width Cu Adhesion Area 1 * 00 Remaining 0.52 0.09 1700 2 * 0.03 0.01 Remaining 0. 50 0.07 900 3 0.1 0.1 Remaining 0.51 0.06 0 4 0.5 0.2 Remaining 0.50 0.040 5 3.0 0.08 Remaining 0.52 0.050 6 5.0 0.15 Remainder 0.51 0.05 0

In the table, 1 and 2 are comparative examples, and 3 to 7 are examples of the present invention. From Table 1, it can be seen that when Ag and S coexist, the adhesion of Cu can be suppressed, and that when Ag is 0.1% or more, Cu does not adhere. Also, as the adhesion is suppressed, the fluctuation range of the friction coefficient becomes smaller.

Example 2 Test pieces of various compositions shown in the table of FIG. 4 were prepared by the same manufacturing method as in Example 1, and a baking test was performed under the following conditions. Test machine: shown in FIG. 3 Sliding speed: 15 m / s Load: Gradual increase in load (step type) 50 kgf / 10 min Oil type: base oil Oil temperature: room temperature Counterpart material: S55C quenching (Hv550-650), roughness: 0.5 In FIG. 3, 1 is a lubrication pad, 2 is a hydraulic cylinder,
3 is a test piece, 4 is a disk, 5 is a balance weight, and 6 is a load cell. The test results are shown in the table of FIG.

In the table of FIG. 4, Comparative Example 11 is pure copper and has a low seizure load. Comparative Example 12 is a material corresponding to a conventional lead bronze bearing (equivalent to JIS LBC-3), and has a very low seizure load. In Comparative Examples 13 and 16, the matrix strengthening element was added to pure copper, but the seizure load was slightly higher. In Comparative Example 14, only Ag was added, and the seizure load was about the same as in Comparative Example 13. In Comparative Example 15, only S was added, and the seizure load was very low. In Comparative Example 16, the conformability improving element was added, but the seizure load was only slightly improved. On the other hand, in Examples 1 to 10 of the present invention in which Ag and S coexist, the seizure load is significantly higher.

Example 3 A mixed powder obtained by adding a copper alloy having the composition of Example Material 10 and Comparative Example Material 12 or 16 shown in the table of FIG. 4 to which various additives shown in Table 3 of FIG. (Steel sheet 1.5mm thick (S
PCC)) and then sintered at 750-850 ° C.
After that, it was rolled and sintered again. Thereafter, the seizure test described in Example 3 and the wear test under the following conditions were performed. Test machine: shown in FIG. 5 Sliding distance: 756 m Load: 98 N Oil type: base oil Oil temperature: 30 ° C. Counterpart material: S55C quenched (Hv 550 to 650), roughness: 0.5 to 0.8 μm Rz In FIG. Is a leaf spring, 11 is a lever, 12 is a thermocouple, 13 is a test piece, 14 is a test shaft as a mating material, 15
Is an oil bath. The test results are shown in the table of FIG.

From the table of FIG. 6, it can be seen that graphite, Al 2 O 3, SiO 2, Si 3
It is clear that the seizure load is improved by adding N4, Fe3P, FeB, NiB, BN and SiC. In addition, the materials 18 to 26 of the examples of the present invention have good results in abrasion resistance, but the materials 29 and 30 of the comparative examples to which a large amount of graphite as a solid lubricant is added are easily worn. .

Example 4 Example material 10, comparative example material 12 in the table of FIG. 4 and comparative example material 27 in the table of FIG.
After spraying on C), sintering was performed at 750 to 850 ° C., and then the resin shown in Table 3 was impregnated into the sintered pores. The resin-impregnated bearing thus obtained was subjected to the baking test of Example 2 and Example 3
Are shown in Tables 2 and 3.

[0028]

[Table 2] No Base material Sliding on resin Characteristics Remarks Resin additive Seizure load Wear depth (Wt% ) (kgf / mm2) ( μm) 32 Example 10 without PAI 1100 20 Example 33 Example 10 without PTFE 1150 25 Example 34 Example 10 without PEEK 1050 20 Example 35 Example 10 without PI 1100 20 Example 36 Example 10 PAI 50% MoS2 1300 10 Example 37 Example 10 PAI 30% MoS2 1250 10 Example 38 Example 10 PAI 10% MoS2 1200 15 Example 39 Example 10 PAI 30% Gr 1200 10 Example 40 Example 10 PAI 20% SiO2 1100 15 Example 41 Example 10 PAI 30% Carbon 1050 10 Example Fiber 42 Example 10 PTFE 50% Pb 1350 25 Example 43 Example 10 PTFE 50% Pb-Sn 1350 25 Example Example Alloy 44 Example 10 PTFE 20% glass 1050 20 Example Fiber 45 Example 10 PTFE 20% Al2O3 1100 20 Example 46 Example 10 PTFE 20% Zn1 00 15 Example 47 Example 10 PEEK 20% of carbon 1100 15 Example Fiber

[0029]

[Table 3] No Base material Sliding on resin Characteristics Remarks Resin additive Seizure load Wear depth (Vol% ) (kgf / mm2) ( μm) 48 Comparative Example 12 Without PAI 700 35 Comparative Example 49 Comparative Example 12 PTFE 50% Pb 900 35 Comparative Example 50 Comparative Example 27 Without PTFE 850 40 Comparative Example

From Table 2, it is clear that the materials 32 to 47 obtained by impregnating resin into a copper-based sliding material in which Ag and S coexist have an improved seizure load. Further, the material 3 of the embodiment of the present invention
Nos. 2 to 47 obtained good results in abrasion resistance.

[0031]

As described above, the copper-based sliding material of the present invention can be applied to any bearing with or without overlay, and improves the seizure resistance of the copper-based sliding material of the conventional composition. It is an epoch-making thing which can raise the seizure resistance of the copper which does not have the additive component of the conventional composition more than the conventional material.

[Brief description of the drawings]

FIG. 1 shows a sliding surface after sliding the sliding material of the present invention.
It is the figure (5000 times magnification) which showed the Ag detection area obtained by IMS analysis with a spot.

FIG. 2 is a diagram showing S detection areas obtained by performing SIMS analysis on the same analysis surface as in FIG.

FIG. 3 is a view of a seizure tester.

FIG. 4 is a table showing the results of a seizure test.

FIG. 5 is a diagram of a wear tester.

FIG. 6 is a table showing the results of a seizure test.

[Description of Signs] 1 Oil pad 2 Hydraulic cylinder 3 Test piece 4 Disk 5 Balance weight 6 Load cell 10 Leaf spring 11 Lever 12 Thermocouple 13 Test piece 14 Test axis 15 Oil bath

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 9/00-9/10 B22F 7/00

Claims (7)

(57) [Claims] 1. Ag to 0.1 to 5% by weight and 0.001
A copper-based sliding material containing up to 1% by weight of S and the balance substantially consisting of Cu and unavoidable impurities. 2. Sn of up to 20% by weight, P of up to 0.5% by weight, Al of up to 5% by weight, Si of up to 1% by weight,
The composition further comprises one or more members selected from the group consisting of Mn by weight or less, Cr by 5% by weight, Ni by 5% by weight and Zn by 30% by weight. 2. The copper-based sliding material according to 1. 3. The copper-based sliding material according to claim 1, further comprising one or two selected from the group consisting of Pb and Bi in a total amount of 30% by weight or less. 4. The method according to claim 1, further comprising one or more selected from the group consisting of graphite, MoS2 and WS2 in an amount of not more than 20% by volume. Copper-based sliding material. 5. A total of not more than 20% by volume of Al2 O3, S
iO2, Si3 N4, Fe3 P, FeB, NiB, BN
The copper-based sliding material according to any one of claims 1 to 4, further comprising one or more members selected from the group consisting of SiC and SiC. 6. The copper-based sliding material according to claim 1, wherein the copper-based sliding material is a sintered material obtained by sintering a back metal, and the sintered pores are impregnated with a resin. Copper-based sliding material. 7. The copper-based sliding material according to claim 6, wherein a surface of the sintered material impregnated with the resin is coated with the resin.