JPH07118777A - Sliding member - Google Patents

Abstract

PURPOSE:To secure wear resistance, seizure resistance, and stable friction coefficient, required of a sintered copper alloy used under wet conditions, and also to improve corrosion resistance to lubricating oil. CONSTITUTION:This member is a sliding member of sintered copper alloy which has a composition consisting of >15-40% Zn, 0.5-6% graphite, 0.5-6% of one or >=2 kinds selected from the group consisting of Al2O3 SiO2 and Fe3P, and the balance essentially Cu and containing, if necessary, one or >=2 kinds selected from the group consisting of <=10% Sn, <=0.5% P, and <=5% of Al, Si, Ni, Cr, and Ag and/or <=30% of Pb and Bi.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered copper alloy sliding member used for parts requiring frictional characteristics and sliding characteristics.

[0002]

BACKGROUND OF THE INVENTION JP-A-63-31293 relates to a copper-based sliding material that exhibits excellent sliding characteristics under boundary lubrication conditions.
According to Japanese Patent Publication No. 3, 1-10% graphite and 1-7% alumina are essential components, and 1-10% Sn and / or 1-30% Pb and P (phosphorus) 1% or less are optional components. A copper-based sintered material containing alumina particles dispersed in a copper matrix has been proposed.

Further, as a copper alloy for a synchronizer ring, according to Japanese Patent Publication No. 4-80105, Cu: 50.
~ 65%; Al: 1-6%; Si: 0.5-5%; N
A composition having i: 5.1 to 8%, Fe: 0.1 to 1%, and the balance Zn has been proposed.

As an alloy to which a component for imparting frictional properties is added, for example, according to JP-A-58-157928, Cu: 60-80% by weight, Sn: 3-
10%, Zn: 15% or less, metal oxide consisting of hard particles: 3 to 20%, graphite: 3 to 10%, MoS2: 1 to 5
%, Pb: 8% or less, CaF2: 10% or less, and M
A copper-based sintered alloy containing n: 15% or less has been proposed.
It is described that this alloy has a relatively high coefficient of friction, is resistant to the thermal fade phenomenon and the water fade phenomenon, and is suitable as a dry friction material having improved aggression and squeal for the mating material.

Further, according to JP-A-60-116751, by weight ratio, Cu: 50 to 85%; Si: 2 to
6%, Zn: 2 to 15%, Pb: 2 to 38%; Lubricating components such as graphite, molybdenum dioxide, coke, mica, carbon black: 2 to 10%, silica, mullite, carborundum, alumina, zircon, A sintered alloy containing 2 to 20% of a lubricating component such as magnesium oxide has been proposed.

Next, according to Japanese Patent Laid-Open No. 61-207549, Cu: 30 to 70% by weight; Sn and Zn:
A sintered alloy composed of 4 to 20% (total amount), graphite: 5 to 15%, sulfide solid lubricant: 0.3 to 7%, and hard nitride 21 to 50% has been proposed. This sintered alloy is described as a friction material useful as a disc brake pad material and a clutch fading material.

[0007]

With the recent trend toward higher engine output and higher engine speed, the operating conditions for sliding materials used in transmissions and the like have become stricter. Further, from the viewpoint of guaranteeing the long-term service life of automobiles, the performance improvement of bearings is required.

However, the Cu-graphite-Al2O3-Sn (Pb) -P type sintered material according to Japanese Patent Laid-Open No. 63-123933 is used as a lubricating oil when it is used for a long time in a transmission part where sliding characteristics are important. As a result, the copper matrix is corroded, and as a result, not only the surface characteristics and strength of the copper matrix are deteriorated, but also Al2 O3 particles may fall off to deteriorate wear resistance and seizure resistance.

The synchronizer ring of a transmission is a component that requires both frictional characteristics and sliding characteristics, but its usage conditions are also strict, and conventional copper alloys have a friction coefficient due to plastic deformation, wear, seizure, etc. May decrease and may cause synchronization problems such as gear noise. In addition, under the present circumstances where it is important to ensure long-term performance under severe operating conditions, the reliability of conventional copper alloys is insufficient. From this point of view, the copper alloy disclosed in Japanese Patent Publication No. 4-80105, which is intended to be used for the synchronizer ring, has few hard components that significantly increase the friction coefficient, and therefore a stable high friction coefficient can be obtained. It is considered that the resistance to seizure is insufficient and the seizure resistance is insufficient.

JP-A-58-157928 and JP-A-60.
The copper-based sintered materials proposed in JP-A-1116751, JP-A-61-207549 and the like are those to which a hard component is added, and therefore exhibit excellent performance in a dry system, but use a synchronizer ring or the like. 100 under wet conditions
The performance when exposed to a high temperature transmission lubricating oil of about 200 ° C. for a long time has not been examined.

The present invention is required for transmission parts where sliding characteristics are important, and for sintered copper alloy sliding members used under wet conditions such as synchronizer rings where sliding characteristics and friction characteristics are required to be at substantially the same level. Sintered copper alloy sliding members that have various properties such as wear resistance, seizure resistance, stable friction coefficient, etc., and improved corrosion resistance against lubricating oil, which was insufficient with conventional materials. The purpose is to provide.

[0012]

The sliding member according to the first aspect of the present invention, which solves the above-mentioned problems, has a Zn content of more than 15% by weight and 40% by weight or less, graphite of 0.5 to 6% by weight, and Al2 O.
1 selected from the group consisting of 3, SiO2 and Fe3 P
Or a sintered alloy containing two or more kinds of 0.5 to 6% by weight, and the balance being substantially Cu. A second aspect of the present invention is a sintered alloy further containing 10 wt% or less of Sn, and a third aspect of the present invention is further 0.5 wt% or less of P.
Sintered alloy containing Al, fourth, further 5% by weight or less A
Sintered alloy containing one or more selected from the group consisting of 1, Si, Ni, Cr and Ag, and Fifth, further selected from the group consisting of 30% by weight or less of Pb and Bi. The sintered alloys containing one kind or two kinds are used respectively. In addition, Al2 O3, SiO2 and Fe
When the average particle size of one or more selected from the group consisting of 3 P is 20 to 200 μm, a sintered alloy having a surface condition particularly preferable for obtaining a stable friction coefficient can be obtained. In addition, the resin in the pores of the sintered alloy is 10
It is possible to improve the seizure resistance by impregnating within the range of 50% by volume.

The structure of the present invention will be described in detail below. In the sliding member according to the first aspect of the present invention, Al2 O3, SiO2
One or two selected from the group consisting of Fe3 P and Fe3 P is a hard dispersant, which suppresses wear of the sintered alloy and enhances strength, suppresses wear, and sets the friction coefficient to a high value.

FIG. 2 shows a Cu-20% Z test method described later.
It is a graph which shows the result of having measured the seizure load and wear depth of n-4% graphite-0 to 10% Al2O3 series sintered alloy.
From this figure, it can be seen that the wear depth decreases with the addition amount of Al2 O3 and the wear resistance improves, while the seizure load decreases with the addition amount of Al2 O3 and the seizure resistance decreases. In the present invention, based on the above results, the amount of hard dispersant was limited as follows. That is, if the content of the hard dispersant is less than 0.5%, the abrasion resistance is insufficient.
On the other hand, when the content of the hard dispersant exceeds 6% by weight, the strength of the copper alloy is insufficient and the load resistance is insufficient. Therefore, the content of the hard particles needs to be in the range of 0.5 to 6% by weight, the preferable content is 2 to 5% by weight, and the more preferable content is 3 to 4% by weight.

Graphite is a component that disperses in the Cu matrix or its grain boundaries to impart lubricity. FIG. 3 shows Cu-
It is a graph which shows the result of having measured the baking load and wear depth of 20% Zn-0 to 15% graphite-2% Al2O3 system sintered alloy. From this figure, it can be seen that the seizure load increases with the amount of graphite added, while the wear depth increases. In the present invention, the graphite content was determined as follows based on this result. That is, if the graphite content is less than 0.5% by weight, seizure is likely to occur due to insufficient lubricity, while if it exceeds 6% by weight, the strength and wear resistance of the sintered copper alloy deteriorate. Therefore, the content of graphite needs to be in the range of 0.5 to 6% by weight, the preferable content is 2 to 5% by weight, and the more preferable content is 3 to 4% by weight.

Zn is a component that improves the corrosion resistance of the Cu alloy against the transmission lubricating oil. Corrosion of Cu alloys is considered to be chemical corrosion in which S-containing corrosion components in the transmission react with Cu to form sulfides.
When such corrosion occurs, copper sulfide is fragile and peels off due to sliding, resulting in a rapid increase in wear of the sliding member and a large change in size and shape, resulting in insufficient sliding characteristics of the sliding member. Such performance degradation occurs during long-term use.

FIG. 1 is a graph showing the results of measuring the X-ray intensity of CuS formed on the surface of Cu-0-50% Zn-4% graphite-2% Al2 O3 series sintered alloy by the method described later. is there. From this figure, when the Zn content is 20% or more, Z
It can be seen that nS is not detected. Therefore, in order to substantially prevent Cu from being sulfided, it is necessary to contain Zn in an amount exceeding 15% by weight in the Cu alloy. On the other hand, when the content of Zn exceeds 40% by weight, β of Cu-Zn
The content of Zn must be in the range of 15 to 40 wt% because the amount of crystallized phase increases, the uniformity of the Cu matrix decreases, and the retention of hard materials and graphite decreases. A preferable Zn content is 15 to 25% by weight, and a more preferable content is 17 to 20% by weight.

The balance of the above components is Cu and inevitable impurities.

The sliding material according to the second aspect of the present invention further comprises 10
It contains Sn by weight or less. These components are dispersed in the Cu matrix as a soft phase to provide lubricity. However, if the Sn content exceeds 10% by weight, the cohesiveness of the sliding material increases and the amount of Zn in solid solution in Cu decreases, so the Sn content must be 10% by weight or less. is there. The preferable Sn content is 0.5 to 8
%, And more preferably 4 to 6% by weight.

The sliding material according to the third aspect of the present invention is obtained by further adding 0.5% by weight or less of P to the first or second sliding material. P is a component that strengthens Cu by adding a small amount. If the P content exceeds 0.5% by weight, the Cu material becomes brittle, so it is necessary that the P content be 0.5% by weight or less. The preferred P content is 0.02
0.1% by weight, more preferably 0.04 to 0.0
6% by weight.

The sliding material according to the fourth aspect of the present invention comprises the first to third materials containing 5% by weight or less of one or more of Al, Ni, Ag, Si and Cr. is there. Among these elements, Al, Ni, and Ag are solid-dissolved in a Cu matrix, and Si and Cr are elements that strengthen Cu by existing as a secondary phase. If the content of these elements exceeds 5% by weight, the Cu material becomes brittle and the sliding characteristics become poor. Therefore, the content should be 5% by weight or less. The preferred content of Al or the like is 0.2 to
It is 2% by weight, and more preferably 0.5 to 1% by weight.

The sliding material according to the fifth aspect of the present invention contains one or two selected from the group consisting of Pb and Bi below, particularly when the required level of sliding characteristics is high. . Pb and Bi impart lubricity as a soft component, but if the content exceeds 30% by weight, the strength of the sliding member decreases and the friction coefficient also decreases, so the content must be 30% by weight or less. . The content of Pb and / or Bi is preferably 5 to 15% by weight, more preferably 8 to 12
% By weight.

In order to stabilize the friction coefficient of the sliding member of the present invention, it is important to suppress the corrosion due to the transmission lubricating oil as described above. For that purpose, a predetermined amount of Zn is added to the Cu alloy. It is necessary. On the other hand, even if the change in the surface state due to corrosion is suppressed, the phenomenon that the surface of the hard particles is covered with Cu during sliding occurs, and this also causes the friction coefficient to change considerably.
To deal with such fluctuations, Al2 O3, Si
It is preferable that one or more hard particles selected from the group consisting of O2 and Fe3 P have an average particle diameter of 20 to 200 .mu.m.

FIG. 4 shows a schematic structure of particles of the sliding member according to the present invention. In the figure, 1 is Cu alloy powder, 2 is graphite, 3
Is a hard particle, 4 is a hole, and 5 is a back metal. The Cu alloy powder No. 1 generally has a particle size of several tens to several hundreds of μm, and forms a skeleton structure by sintering. The sliding member is formed by polishing the surface of the sintered alloy to some extent to form a sliding surface. If the particle size of the hard particles is too small, the Cu alloy covers the hard particles during sliding on the sliding surface shown as SS, while if the particle size is too large, the hard particles are outside the skeleton of the sintered structure. Existing in the pores, the adhesion is weak and easily slips off, and when slipping off, the roughness of the sliding surface changes greatly, and in either case, the friction coefficient becomes unstable.

FIG. 5 shows Cu-20% Zn-4% graphite-2.
5 is a graph showing the fluctuation range of the friction coefficient when the average particle size of Al2 O3 particles of a% Al2 O3 series sintered alloy is changed. From this figure, it is not desirable that the average particle size of the hard particles is less than 20 μm because the fluctuation range of the friction coefficient is large and the friction coefficient is low. It can be seen that the coefficient is high and stable. The preferable average particle size of the hard particles is 30 to 150 μm.
m, and more preferably 40 to 80 μm.

Further, according to the sixth aspect of the present invention, in order to improve the seizure resistance of the above-mentioned metal-inorganic material type sliding member, the resin is contained in the pores of the sintered alloy in an amount of 10 to 50% by volume based on the whole.
Impregnate within the range. As the resin, polyimide (P
I), phenol, polyamideimide (PAI), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), polyetherimide (PE
I) and the like can be used, among which polyamide imide (PA
I) can be preferably used.

FIG. 6 shows Cu-20% Zn-4% graphite-2.
5 is a graph showing the results of measuring the seizure load and wear depth of a sliding member obtained by impregnating the pores of a% Al2 O3 series sintered alloy with PAI resin. It can be seen from FIG. 6 that the seizure load increases with the resin impregnation amount, but the wear depth also increases.
From the results of FIG. 6, when the volume of the impregnated resin is less than 10% with respect to the entire sliding member, there is no effect, while when it exceeds 50%, the sintered alloy becomes porous and its strength is significantly reduced. 10 to 50% by volume because the wear caused by
It is necessary to be within the range. The preferred impregnation amount is 20
-40% by volume, more preferably 25-35% by volume
Is.

The method of manufacturing the sliding member of the present invention will be described below. Additive elements such as graphite, hard particles, and Sn, Bi, and Pb other than Zn are added to the molten metal of the copper alloy when the molten alloy is atomized, and the molten alloy is atomized to obtain copper alloy powder. Subsequently, the copper alloy powder, the graphite powder, the Zn powder and the hard particle powder are mixed, sprinkled on the back metal, and if necessary, pressurized,
Sintering is performed at 700 to 900 ° C. Thereafter, if necessary, resin impregnation is performed, and the surface of the sintered alloy is polished to reduce the roughness to 1
Finish to about 2 μm Rz. Since Zn has a property of subliming during atomization and sintering, it is difficult to adjust the components.
Particularly when the amount of Zn added exceeds 15% as in the present invention, it is preferable to add Zn as a separate powder and sinter as described above.

[0029]

As described above, in the present invention, hard particles are added to improve the wear resistance of the Cu-based sintered material and to impart a desired friction coefficient, and graphite is added to improve the seizure resistance. , Pb or Bi was added, and Zn was added to improve the corrosion resistance (claims 1 to 5). Further, the particle size of the hard particles is defined to stably maintain a high friction coefficient (claim 6). In order to further improve the seizure resistance, the pores of the sintered alloy were impregnated with resin (claim 7). Hereinafter, the present invention will be described in more detail with reference to examples.

[0030]

Example A sintered alloy having the composition shown in Table 1 was manufactured. Cu
The particle size of alloy powder and Zn powder is 10 to 100 μm, the particle size of graphite is 2 to 10 μm, and the particle size of Al2 O3 is 30 to 15 μm.
0 μm, grain size of SiO2 is 30-150 μm, Fe3 P
Had a particle size of 30 to 150 μm. The sintering temperature is 8
It was 00 ° C. This was rolled into a test material.

The sliding property test method is as follows. (1) Seizure test Thrust type tester, V = 7.1 m / sec, W = 0.1
kN / 2min gear oil in oil bath (room temperature), mating material-SCM
20 Carburizing and quenching (ring-shaped test piece with outer diameter 26 mm, inner diameter 20 mm, height 15 mm) Specimen size (30 mm x 30 mm x 5 mm) (2) Wear test Ring-on-block tester, V = 5.5 m / sec , W = 0.27kN Gear oil in oil bath (up to shaft center, room temperature) Counterpart material-SCM20 Carburizing and quenching (external diameter 35mm, internal diameter 30mm, height 20mm ring-shaped test piece) Specimen size (10mm x 16mm X8 mm) (3) Corrosion test Gear oil (135 ° C x 24 hours) Presence / absence of CuS formation confirmed by X-ray diffraction (4) Actual machine test Table 2 shows the test results by a transmission (50,000 cycles).

[0032]

[Table 1] No composition (% by weight) Zn Sn P Gr Ag Al Si Ni Cr Pb Bi Al2O3 SiO2 Fe3P 1 16 − − 4 − − − − − − − 2 − − 2 18 5 0.1 0.5 0.2 0.1 0.1 0.5 0.5 10 − − 5 − 3 20 10 0.5 6 2 − − − 1 − 5 2 − 4 4 40 2 − 2 − 2 − − 3 − − 0.5 − − 5 20 10 0.2 1 − − − 0.5 − 10 2 − 2 − 6 17 5 0.05 4 0.5 − − − − − − 2 − − 7 − 10 − − − − − − − 10 − − − − 8 30 − − − − 3.0 0.9 0.4 0.2 − − − − − 9 − 5 − 6 − − − − − − − 2 − −

[0033]

[Table 2] Seizure load Change in wear depth μ Corrosion resistance Actual machine 1 2.4 28 1.6 → ○ Good 1.4 2 2.2 11 1.5 → ○ Good 1.2 3 3.2 10 1.6 → ○ Good 1.3 4 1.5 29 1.5 → ○ Good 1.0 5 1.9 25 1.6 → ○ Good 1.3 6 2.4 11 1.5 → ○ Good 1.2 7 * 1.0 48 1.5 → × Seizure 0.7 8 * 1.4 32 1.5 → ○ Wear 0.9 9 * 2.9 12 1.7 → × Wear 1.4

In Table 2, the unit of seizure load is kN, the unit of wear depth is μm, and the change in friction coefficient (μ) shows the first and last values of the test. The test material with * is a comparative example.

Comparative Example 7 has no corrosion resistance because it does not contain Zn, has poor wear resistance because it does not contain hard particles, and has a large change in the friction coefficient. In addition, seizure resistance is also poor due to the absence of these components and the absence of graphite.
Burn-in is occurring in the actual machine test. Comparative Example 8 contains a large amount of Zn and therefore has good corrosion resistance. However, since the hard particles were not contained, the wear resistance was poor and the coefficient of friction was significantly changed, though not so much as Comparative Example 7. In Comparative Example 9, the seizure resistance is remarkably improved by the addition of graphite. However, since it does not contain Zn,
Corrosion resistance is poor. Furthermore, the wear resistance of the wear tester is considerably improved by the inclusion of graphite and hard elements, but wear has occurred in the actual machine test that determines the actual performance by combining various characteristics. On the other hand, in the examples of the present application, the performance of all the test machines was good, and neither seizure nor wear occurred in the actual machine. Especially, the total amount of added components is not too large N
o. 6 shows excellent performance.

As in the above example, a predetermined amount of Cu alloy powder, graphite powder, Zn powder, Al2O3 powder, etc. were sintered and the pores were impregnated with PAI resin. Note that the powder dispersion conditions and sintering temperature were controlled, and if necessary, rolling was carried out by a prescribed amount to obtain sintered alloys having various porosities corresponding to FIG. Got See also PAI
A test material was produced by impregnating the resin with various resins. It has been found that the seizure load and wear depth of these sliding members have similar effects within the scope of the present invention.

[0037]

Since the sliding member of the present invention is excellent in corrosion resistance against lubricating oil, it is possible to suppress the thickness reduction during use, as well as the change in friction coefficient and seizure resistance caused by the change in surface characteristics. Can be prevented. In particular, it exhibits excellent performance as a sliding member used in a transmission and the performance is stable.

[Brief description of drawings]

Fig. 1 Z of Cu-Zn-Al2O3-graphite sintered alloy
It is a graph which shows the relationship between n content and the X-ray intensity of CuS.

FIG. 2 is a graph showing the relationship between the content of Al2O3 in a Cu-20% Zn-Al2O3-4% graphite-based sintered alloy, the seizure load, and the wear depth.

FIG. 3 is a graph showing the relationship between the graphite content of a Cu-20% Zn-2% Al2 O3 -graphite sintered alloy and the seizure load and wear depth.

FIG. 4 is a schematic diagram showing a particle structure of a sintered alloy of the present invention.

FIG. 5 is a graph showing the relationship between the friction coefficient and the grain size of Al2O3 in a Cu-20% Zn-2% Al2O3-graphite sintered alloy.

FIG. 6 is a graph showing the relationship between the amount of resin impregnated into Cu-20% Zn-2% Al2 O3-graphite sintered alloy, the seizure load, and the wear depth.

[Explanation of reference symbols]

 1-Cu alloy particle 2-graphite 3-hard particle 4-hole 5-back metal

Front page continued (72) Inventor Hiromi Yokota 3-65 Midorigaoka, Toyota-shi, Aichi Otoyo Kogyo Co., Ltd. (72) Inventor Takashi Tomikawa 3-65 Midorigaoka, Toyota-shi, Aichi Otoyo Kogyo Co., Ltd. (72 ) Inventor Shoji Kamiya 3-65 Midorigaoka, Toyota-shi, Aichi Otoyo Kogyo Co., Ltd. (72) Inventor Kenji Ueno 1 Toyota-cho, Toyota-shi, Aichi Toyota Automobile Co., Ltd. (72) Inventor Hirofumi Michioka Aichi Toyota-cho, Toyota-shi, Toyota-shi, Japan (72) Inventor Yoshio Fuwa, Toyota-cho, Toyota-shi, Aichi, Toyota-shi, Toyota

Claims (7)

[Claims] 1. Zn is more than 15% by weight and 40% by weight or less,
0.5 to 6% by weight of graphite, Al2 O3, SiO2 and Fe
1 type or 2 types or more selected from the group consisting of 3 P.
A sintered alloy sliding member comprising 5 to 6% by weight and the balance being substantially Cu. 2. The sliding member according to claim 1, wherein the sintered alloy further contains 10 wt% or less of Sn. 3. The sliding member according to claim 1, wherein the sintered alloy further contains 0.5% by weight or less of P. 4. The sintered alloy further comprises 5% by weight or less of A.
4. The sliding member according to any one of claims 1 to 3, which contains one or more selected from the group consisting of 1, Si, Ni, Cr and Ag. 5. The sintered alloy further contains 30% by weight or less of one or two selected from the group consisting of Pb and Bi. The sliding member described. 6. The Al2 O3, SiO2 and Fe3 P
The average particle size of one or more selected from the group consisting of is from 20 to 200 μm.
7. The sliding member according to any one of 1 to 6. 7. The slide according to claim 1, wherein the pores of the sintered alloy are impregnated with a resin within a range of 10 to 50% by volume based on the whole. Moving member.