JP2008297361A - Copper-based oil-impregnated sintered sliding member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-based oil-impregnated sintered sliding member exhibiting excellent friction/abrasion properties even without using a solid lubricant such as graphite and molybdenum disulfide. <P>SOLUTION: Disclosed is a copper-based oil-impregnated sintered sliding member in which an inorganic phosphate is dispersedly incorporated into a sintered matrix body essentially consisting of copper, and further, the vacancies thereof are impregnated with lubricating oil. In its sliding with a mating member, a thin film of the inorganic phosphate dispersedly incorporated into the sintered matrix body can be formed on the surface of the mating member, and as a result of a transit to the sliding via this film, conjointly with the lubricating oil impregnated into the vacancies and also lying between the sliding faces, excellent friction/abrasion properties can be exhibited. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a copper-based oil-impregnated sintered sliding member, and more particularly to a copper-based oil-impregnated sintered sliding member having excellent frictional wear characteristics without using a solid lubricant such as graphite or molybdenum disulfide.

Japanese Industrial Standard JISZ2550 (Bearing material impregnated with liquid lubricant) JP-A-55-134147 Japanese Examined Patent Publication No. 60-46161

  In general, oil-impregnated sintered bearings are made by impregnating the pores (pores) of a porous metal sintered matrix with lubricating oil, and typical oil-impregnated sintered bearings are tins defined in JIS standards. (Sn) 9 to 11% by weight, graphite (Gr) 0.5 to 2.0% by weight, other 2% by weight or less, and remaining copper (Cu) are known (described in Non-Patent Document 1). . In addition, a copper-based oil-impregnated sintered bearing containing molybdenum disulfide as a solid lubricant in place of graphite has also been proposed (Patent Document 1).

In the method of using molybdenum disulfide (MoS ₂ ) as a solid lubricant, mixing it with metal powder, forming and sintering, molybdenum (Mo) and sulfur during sintering at a sintering temperature exceeding 700 ° C. There is a problem that the lubricity due to the layered structure inherent to molybdenum disulfide is degraded by thermal decomposition into (S). As a method for solving this problem, attempts have been made to use copper-coated molybdenum disulfide in which the surface of molybdenum disulfide is coated with copper or the like, but there is a problem that the powder of copper-coated molybdenum disulfide is expensive. In addition, as another solution, an attempt to lower the sintering temperature by blending phosphorus (P) has also been proposed. However, the blending of phosphorus necessitates the formation of a brittle phosphorus compound in the sintered metal matrix body, There are problems such as causing a decrease in strength of the sintered metal matrix and reducing sliding performance.

  The present invention has been made in view of the above points, and its object is to provide a copper-based oil-impregnated sintered slide that exhibits excellent frictional wear characteristics without using a solid lubricant such as graphite or molybdenum disulfide. It is to provide a moving member.

  The copper-based oil-impregnated sintered sliding member of the present invention is characterized in that inorganic phosphate is dispersedly contained in a sintered matrix body mainly composed of copper, and that the pores are impregnated with lubricating oil. To do.

  According to the copper-based oil-impregnated sintered sliding member of the present invention, the copper-based oil-impregnated sintered sliding member and the counterpart material are obtained by the action of the inorganic phosphate dispersed in the sintered matrix body mainly composed of copper. As a result of forming a thin coating of inorganic phosphate dispersed and contained in the sintered matrix body on the surface of the mating material and sliding through this coating, the lubricating oil impregnated in the pores is used. Therefore, it exhibits excellent friction and wear characteristics in combination with the lubricating oil interposed between the sliding surfaces. In a sliding member obtained by sintering, it is difficult to form a complete liquid lubricant film on the sliding surface, and it is boundary lubrication with metal contact. Therefore, the formation of a film on the surface of the counterpart material causes galling or seizure. Make it difficult.

  In the present invention, as a preferable example of the inorganic phosphate, at least one of magnesium pyrophosphate, calcium pyrophosphate and trialuminum phosphate is selected and dispersed and contained in the sintered matrix body at a ratio of 0.5 to 5% by weight. It is good to have.

  The sintered matrix body is preferably composed of 0.5 to 15% by weight of tin and the balance copper.

  The sintered matrix body is 0.5 to 15% by weight of tin, and at least one kind selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus as the reinforcing element is 0.1 to 45% by weight. And the balance copper. These zinc, nickel, iron, cobalt, manganese, aluminum, silicon, and phosphorus exert an effect of strengthening a copper-based sintered matrix body composed of tin and copper with respect to strength, toughness, mechanical strength, and wear resistance.

  The pores of the sintered matrix body are preferably impregnated with a lubricating oil at a ratio of 5 to 30% by volume with respect to the total volume of the sintered matrix body.

  According to the present invention, the copper-based oil-impregnated sintered sliding member, in which the inorganic phosphate is dispersed and contained in the sintered matrix body mainly composed of copper and the pores are impregnated with the lubricating oil, and the counterpart material In this sliding, a thin film of inorganic phosphate dispersed and contained in the sintered matrix body can be formed on the surface of the counterpart material, and as a result of being able to move to sliding through this film, the lubricating oil impregnated in the pores Thus, it is possible to provide a copper-based oil-impregnated sintered sliding member that exhibits excellent friction and wear characteristics in combination with the lubricating oil interposed between the sliding surfaces.

  The copper-based oil-impregnated sintered sliding member of the present invention is formed by dispersing inorganic phosphate in a sintered matrix body mainly composed of copper and impregnating the pores with lubricating oil.

In such a copper-based oil-impregnated sintered sliding member, in a preferred example, as an inorganic phosphate dispersedly contained in a sintered matrix body mainly composed of copper, magnesium pyrophosphate (Mg ₂ P ₂ O ₇ ), At least one of calcium pyrophosphate (Ca ₂ P ₂ O ₇ ) and tribasic aluminum phosphate (Al ₃ PO ₄ ) is selected and used.

  These inorganic phosphates are not themselves substances having solid lubricating action such as graphite and molybdenum disulfide, but are dispersed and contained in a sintered matrix body mainly composed of copper, so ) To form a thin film that is transferred to the surface of the mating material, and to move to the sliding through this film, coupled with the lubricating oil interposed between the sliding surfaces. Thus, excellent friction and wear characteristics can be exhibited in the sintered sliding member.

  The proportion of the inorganic phosphate dispersed in the sintered matrix body is preferably 0.5 to 5% by weight. If the amount is less than 0.5% by weight, the above-described effect is not sufficiently exhibited. If the amount exceeds 5% by weight, the strength, toughness, mechanical strength and wear resistance of the sintered matrix body are lowered.

  As the sintered matrix body, a sintered matrix body composed of 0.5 to 15% by weight of a tin component and the remaining copper component is preferable. The tin component is alloyed with the copper component constituting the main component to form a copper-tin alloy, and contributes to the improvement of the strength, toughness, mechanical strength and wear resistance of the sintered matrix body. If the amount of tin component is less than 0.5% by weight, the above-described effects are not sufficiently exhibited. If the amount exceeds 15% by weight, the sinterability is adversely affected. Although a tin component may be mix | blended with a tin component single-piece | unit with respect to a copper component, you may mix | blend, for example with the form of a copper-20% tin alloy.

  In addition, as the sintered matrix body, zinc component, nickel component, iron component, cobalt component, manganese component, aluminum component, silicon component and phosphorus component with respect to 0.5 to 15% by weight of the tin component and the remaining copper component You may contain 0.1 to 45 weight% of at least 1 type of matrix reinforcement | strengthening components selected from these. If the blending amount of the matrix reinforcing component is less than 0.1% by weight, it is not sufficient to enhance the strength, toughness, mechanical strength and wear resistance of the matrix body. It becomes too high to be used as a sliding member.

  These matrix reinforcing components such as zinc component, nickel component, iron component, cobalt component, manganese component, aluminum component, silicon component and phosphorus component may be blended with each component alone, but an alloy of copper and each component, for example, You may mix | blend with forms, such as a copper-30% zinc alloy, a copper-30% nickel alloy, a copper-35% manganese alloy, and a copper-8% phosphorus alloy.

  Among the matrix reinforcing components, particularly, the zinc component and the nickel component are alloyed with copper and a copper-tin alloy as main components to form a copper-tin-zinc alloy or a copper-tin-nickel alloy. This improves the strength, toughness and mechanical strength of the steel and contributes to the improvement of wear resistance.

  Lubricating oil is impregnated in the pores of the sintered matrix body having the above-described component composition at a ratio of 5 to 30% by volume with respect to the total volume of the sintered matrix body.

  The copper-based oil-impregnated sintered sliding member of the present invention is manufactured as follows.

  (1) 0.5-15% by weight of atomized tin powder passing through a 350-mesh sieve, 0.5-5% by weight of inorganic phosphate passing through a 200-mesh sieve, and a lubricant 0.5 such as zinc stearate (2) 0.5 to 15% by weight of atomized tin powder passing through a 350 mesh, zinc powder passing through a 200 to 350 mesh sieve, nickel powder, At least one matrix reinforcing component powder selected from iron powder, cobalt powder, manganese powder, aluminum powder, silicon powder and phosphorus powder, 0.1 to 45% by weight, zinc stearate 0.5% by weight as a lubricant, and the balance Each of the electrolytic copper powders passing through a 150 mesh sieve is put into a V-type mixer and mixed for 30 minutes to obtain a mixed powder. In addition, zinc stearate plays a role as a lubricant when taking out a green compact to be described later from a mold.

After the mixed powder is loaded into a hollow part of a mold having a hollow part of a desired shape and molded at a molding pressure of 1.5 to 4 ton / cm ² (147 to 392 MPa), a molded green compact is produced. This molded green compact is sintered at a temperature of 750 to 900 ° C. for 30 to 120 minutes in a sintering furnace adjusted to a neutral or reducing atmosphere. The obtained sintered body is subjected to mechanical processing such as sizing to produce the desired sintered sliding member, and then subjected to oil impregnation under reduced pressure to impregnate the lubricating oil and lubricate the pores of the sintered body. A copper-based oil-containing sintered sliding member impregnated with 5 to 30% by volume of oil is produced.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to a following example, unless the summary is exceeded.

Examples 1-3
9% by weight of atomized tin powder that passes through a 350 mesh sieve, and 1.5% by weight of any one of magnesium pyrophosphate, calcium pyrophosphate, and aluminum triphosphate that pass through a 200 mesh sieve as inorganic phosphate Then, 0.5% by weight of zinc stearate as a lubricant and electrolytic copper powder passing through a 150 mesh screen were put into a V-shaped mixer and mixed for 30 minutes to obtain a mixed powder (9% by weight of tin) Inorganic phosphate 1.5% by weight, zinc stearate 0.5% by weight, copper 89.0% by weight). This mixed powder is loaded into a hollow part of a mold having a hollow part with a side length of 30.5 mm and a depth of 4.5 mm, and molded at a molding pressure of 2 ton / cm ² , A green compact was obtained. This molded green compact was sintered at a temperature of 780 ° C. for 30 minutes in a sintering furnace adjusted to a hydrogen gas atmosphere to obtain a sintered body. Next, sizing was performed on the sintered body to obtain a sintered sliding member having a side of 30 mm and a thickness of 4 mm, and this was subjected to oil impregnation treatment under reduced pressure to obtain 12% by volume of lubricating oil (turbine oil). An impregnated copper-based oil-impregnated sintered sliding member was obtained.

Examples 4-5
9% by weight of atomized tin powder passing through a 350 mesh screen, 1.5% by weight of magnesium pyrophosphate passing through a 200 mesh screen as inorganic phosphate, and 4.5% reduced iron powder passing through a 240 mesh screen 4.5% by weight of pulverized manganese powder that passes through a sieve of 250% or 250 mesh, 0.5% by weight of zinc stearate as a lubricant, and electrolytic copper powder that passes through 150 mesh as a lubricant are put into a V-type mixer. And mixed for 30 minutes to obtain a mixed powder (tin 9% by weight, inorganic phosphate 1.5% by weight, iron or manganese 4.5% by weight, zinc stearate 0.5% by weight, copper 84.5% weight%). This mixed powder was loaded into a hollow part of a mold similar to that in the above example and molded at a molding pressure of 2 ton / cm ² to obtain a square shaped green compact. This molded green compact was sintered at a temperature of 780 ° C. for 30 minutes in a sintering furnace adjusted to a hydrogen gas atmosphere to obtain a sintered body. Next, after sizing the sintered body to obtain a sintered sliding member having a side of 30 mm and a thickness of 4 mm, this was subjected to oil impregnation treatment under reduced pressure to obtain 12 vol% lubricating oil (turbine oil). An impregnated copper-based oil-impregnated sintered sliding member was obtained.

Example 6
7% by weight of atomized tin powder passing through 350 mesh, 1.5% by weight of magnesium pyrophosphate passing through 200 mesh as inorganic phosphate, 30% by weight of atomized copper-30% zinc alloy powder passing through 200 mesh Then, 0.5% by weight of zinc stearate as a lubricant and electrolytic copper powder with the remainder passing through 150 mesh were put into a V-type mixer and mixed for 30 minutes to obtain a mixed powder (7% by weight of tin, inorganic Phosphate 1.5% by weight, zinc 9% by weight, zinc stearate 0.5% by weight, copper 82% by weight). A sintered sliding member having a side of 30 mm and a thickness of 4 mm was obtained from this mixed powder in the same manner as in the above example, and then subjected to oil impregnation treatment under reduced pressure to obtain a 12 volume% lubricating oil (turbine A copper-based oil-impregnated sintered sliding member impregnated with (oil) was obtained.

Example 7
7% by weight of atomized tin powder passing through 350 mesh, 1.5% by weight of magnesium pyrophosphate passing through 200 mesh as inorganic phosphate, 30% by weight of copper-30% nickel alloy powder passing through 200 mesh, As a lubricant, 0.5% by weight of zinc stearate and electrolytic copper powder with the remainder passing through 150 mesh were put into a V-shaped mixer and mixed for 30 minutes to obtain a mixed powder (7% by weight of tin, inorganic phosphorus Acid salt 1.5% by weight, nickel 9% by weight, zinc stearate 0.5% by weight, copper 82% by weight). This mixed powder is loaded into a hollow part of a mold having a hollow part with a side length of 30.5 mm and a depth of 4.5 mm, and molded at a molding pressure of 2 ton / cm ² , A green compact was obtained. This molded green compact was sintered at a temperature of 850 ° C. for 60 minutes in a sintering furnace adjusted to a hydrogen gas atmosphere to obtain a sintered body. Hereinafter, after obtaining a sintered sliding member having a side of 30 mm and a thickness of 4 mm in the same manner as in the above-described embodiment, it was subjected to oil impregnation under reduced pressure, and 12 volume% of lubricating oil (turbine oil) was applied. An impregnated copper-based oil-impregnated sintered sliding member was obtained.

Comparative Example 1
9% by weight of atomized tin powder passing through 350 mesh, 2% by weight of natural graphite powder having an average particle size of 40 μm, 0.5% by weight of zinc stearate as a lubricant, and electrolytic copper powder with the remainder passing through 150 mesh The mixture was put in a V-shaped mixer and mixed for 30 minutes to obtain a mixed powder. This mixed powder was sintered at 780 ° C. in the same manner as in the above example to obtain a sintered sliding member having a side of 30 mm and a thickness of 4 mm. A copper-based oil-impregnated sintered sliding member impregnated with 100% lubricating oil (turbine oil) was obtained.

Comparative Example 2
9% by weight of atomized tin powder passing through a 350 mesh screen, 6% by weight of pulverized manganese powder passing through a 250 mesh screen, 1% by weight of natural graphite powder having an average particle size of 40 μm, and zinc stearate as a lubricant. 5 wt% and the electrolytic copper powder with the remainder passing through 150 mesh were put into a V-shaped mixer and mixed for 30 minutes to obtain a mixed powder. This mixed powder was sintered at 780 ° C. in the same manner as in the above example to obtain a sintered sliding member having a side of 30 mm and a thickness of 4 mm. A copper-based oil-impregnated sintered sliding member impregnated with 1% lubricating oil (turbine oil) was obtained.

Comparative Example 3
7% by weight of atomized tin powder passing through 350 mesh, 30% by weight of atomized copper-30% zinc alloy powder passing through 200 mesh, 2% by weight of natural graphite powder having an average particle size of 40 μm, and zinc stearate as a lubricant 0.5 wt% and electrolytic copper powder with the remainder passing through 150 mesh were put into a V-shaped mixer and mixed for 30 minutes to obtain a mixed powder (7 wt% tin, 9 wt% zinc, 2 wt% graphite). %, Zinc stearate 0.5% by weight, copper 81.5% by weight). This mixed powder was sintered at 780 ° C. in the same manner as in the above example to obtain a sintered sliding member having a side of 30 mm and a thickness of 4 mm. A copper-based oil-impregnated sintered sliding member impregnated with 100% lubricating oil (turbine oil) was obtained.

  The copper-based oil-impregnated sintered sliding members of Examples 1 to 3 and Comparative Example 1 described above were tested for friction and wear characteristics under the test conditions shown in Table 1.

(Table 1)
(Friction and wear test 1)
Load (surface pressure) 1.96 MPa (20 kgf / cm ² )
Sliding speed 20m / min
Test time 20 hours Mating material Carbon steel for machine structure (S45C)
Motion form Thrust test

  The above-described copper-based oil-impregnated sintered sliding member of Examples 4 and 5 and the copper-based oil-impregnated sintered sliding member of Comparative Example 2 were tested for friction and wear characteristics under the test conditions shown in Table 2.

(Table 2)
(Friction and wear test 2)
Load (surface pressure) 4.9 MPa (50 kgf / cm ² )
Sliding speed 20m / min
Test time 20 hours Mating material Carbon steel for machine structure (S45C)
Motion form Thrust test

  The above-described copper-based oil-impregnated sintered sliding member of Examples 6 and 7 and the copper-based oil-impregnated sintered sliding member of Comparative Example 3 were tested for friction and wear characteristics under the test conditions shown in Table 3.

(Table 3)
(Friction and wear test 3)
Load (surface pressure) 14.7 MPa (150 kgf / cm ² )
Sliding speed 5m / min
Test time 20 hours Mating material Carbon steel for machine structure (S45C)
Motion form Thrust test

  The test results of the relationship between the test time and the friction coefficient under the test conditions in Table 1 are shown in FIG. 1, the test results of the relationship between the test time and the friction coefficient under the test conditions in Table 2 are shown in FIG. FIG. 3 shows the test results of the relationship between the test time and the friction coefficient according to conditions, and FIG. 4 shows the wear amount of the copper-based oil-impregnated sintered sliding members of the examples and comparative examples after the test.

  From the test results, the copper-based oil-impregnated sintered sliding members of Examples 1 to 3 that do not contain a solid lubricant such as graphite are the copper of Comparative Example 1 containing graphite as a solid lubricant in terms of friction coefficient and wear amount. The copper-based oil-impregnated sintered sliding member of Examples 4 to 5 exhibits a frictional wear characteristic equivalent to or higher than that of the oil-based sintered sintered member. The copper-based oil-impregnated sintered sliding member of Examples 6 to 7 is superior in the coefficient of friction and the amount of wear than the copper-based oil-impregnated sintered sliding member of Comparative Example 3. Recognize. In addition, since the friction coefficient of the copper-based oil-impregnated sintered sliding member of Comparative Example 2 in FIG. 2 rapidly increased in the test time of 8 hours, the test was stopped, and the copper-based oil-impregnated sintered member of Comparative Example 3 in FIG. The sliding member was stopped from the test because the friction coefficient increased rapidly after 18 hours. The amount of wear indicates the amount of dimensional change of the copper-based oil-impregnated sintered sliding member at the end of the test.

  In the copper-based oil-impregnated sintered sliding members of Examples 1 to 7, the friction coefficient showed a high value in the initial stage of friction, but it decreased with the lapse of the test time, and the friction coefficient was very low (0.01 to 0.00). 06) showed stable sliding. This confirms that a thin coating of inorganic phosphate dispersed and contained in the sintered matrix body is formed on the surface of the counterpart material after the tests of the copper-based oil-impregnated sintered sliding members of Examples 1 to 7. This is presumed to be due to the transition to sliding through this film.

  As described above, the copper oil-impregnated sintered sliding member of the present invention exhibits friction and wear characteristics superior to those of a copper oil-impregnated sintered sliding member containing a solid lubricant such as graphite or molybdenum disulfide.

It is a graph which shows the relationship between test time and a friction coefficient. It is a graph which shows the relationship between test time and a friction coefficient. It is a graph which shows the relationship between test time and a friction coefficient. It is a graph which shows the abrasion loss of the copper type oil-containing sintered sliding member after a test.

Claims (6)

  A copper-based oil-impregnated sintered sliding member characterized in that an inorganic phosphate is dispersedly contained in a sintered matrix body mainly composed of copper and the pores are impregnated with lubricating oil. Copper oil-impregnated sintered sliding member.   The copper-based oil-impregnated sintered sliding member according to claim 1, wherein at least one of magnesium pyrophosphate, calcium pyrophosphate, and tertiary aluminum phosphate is dispersedly contained as the inorganic phosphate.   The copper-based oil-impregnated sintered sliding member according to claim 1 or 2, wherein the inorganic phosphate is dispersed and contained in the sintered matrix body at a ratio of 0.5 to 5% by weight.   The copper-based oil-impregnated sintered sliding member according to any one of claims 1 to 3, wherein the sintered matrix body is made of 0.5 to 15% by weight of tin and the remaining copper.   The sintered matrix body includes 0.5 to 15% by weight of tin, 0.1 to 45% by weight of at least one selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus, and the balance copper. The copper-based oil-impregnated sintered sliding member according to any one of claims 1 to 3.   The copper-based oil-impregnated grill according to any one of claims 1 to 5, wherein the lubricating oil is impregnated in pores of the sintered matrix body in an amount of 5 to 30% by volume with respect to the total volume of the sintered matrix body. Bonding sliding member.

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