JP2009079136A - Copper-based, oil-impregnated and sintered sliding member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-based, oil-impregnated and sintered sliding member exhibiting excellent frictional abrasion characteristics even on without using a solid lubricant such as graphite, molybdenum disulfide, etc. <P>SOLUTION: This copper-based, oil-impregnated and sintered sliding member comprises 0.5 to 10 wt.% of inorganic phosphate dispersed in a sintered matrix consisting of 0.5 to 15 wt.% of tin, 0.1 to 45 wt.% of at least one selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus, and the rest of copper, and also a lubricant oil impregnated in its vacant holes. <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 (Non-Patent Document 1 publication) ). 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 reduced due to thermal decomposition into (S). As a method for solving this problem, there has been proposed an attempt to use copper-coated molybdenum disulfide whose surface is coated with copper or the like, but there is a problem that the powder of copper-coated molybdenum disulfide is expensive. As another solution, an attempt to lower the sintering temperature by adding phosphorus (P) has also been proposed. However, the addition of phosphorus necessitates the formation of a brittle phosphorus compound in the sintered metal matrix, 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 0.5 to 15% by weight of tin and 0.1 to 45% by weight selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus. % And the remaining copper is dispersed and contained in a ratio of 0.5 to 10% by weight, and the pores are impregnated with lubricating oil. .

  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 preferred 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 10% by weight. It is good to have.

  As the sintered matrix body, 0.5 to 15 wt% tin, and 0.1 to 45 wt% at least one selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus as reinforcing elements, It consists of 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 0.5 to 15% by weight of tin and 0.1 to 45% by weight selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus. % And the remaining copper is dispersed in a proportion of 0.5 to 10% by weight, and the pores are impregnated 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. The sintered sliding member can exhibit excellent friction and wear characteristics.

  The proportion of the inorganic phosphate dispersed in the sintered matrix body is preferably 0.5 to 10% by weight. If the amount is less than 0.5% by weight, the above-described effect is not sufficiently exhibited. If the amount exceeds 10% by weight, the strength, toughness, mechanical strength and wear resistance of the sintered matrix body are lowered.

  As the sintered matrix body, 0.5 to 15 wt% tin, and 0.1 to 45 wt% at least one selected from zinc, nickel, iron, cobalt, manganese, aluminum, silicon and phosphorus as reinforcing elements, It consists of the balance copper.

The tin component in the sintered matrix body is alloyed with the copper component, which is the main component, to form a copper-tin alloy, contributing to the improvement of the strength, toughness, mechanical strength and wear resistance of the sintered matrix body. To do. If the amount of tin component is less than 0.5% by weight, the above-described effects are not sufficiently exhibited, and 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.

  The sintered matrix body contains 0.1 to 45% by weight of at least one matrix reinforcing component selected from zinc component, nickel component, iron component, cobalt component, manganese component, aluminum component, silicon component and phosphorus component. Yes. 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.

  Atomized tin powder passing through a 250 mesh sieve 0.5 to 15% by weight, zinc powder passing through a 200 to 350 mesh sieve, nickel powder, iron powder, cobalt powder, manganese powder, aluminum powder, silicon powder and phosphorus powder 0.1 to 45% by weight of at least one matrix reinforcing component powder selected from: electrolytic copper powder with the remainder passing through a 150 mesh sieve, inorganic phosphate 0.5 to 10% by weight passing through a 200 mesh sieve Then, 0.5% by weight of zinc stearate as a lubricant 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 passing through a 250 mesh screen, 1.5-5% by weight of magnesium pyrophosphate passing through a 200 mesh screen as inorganic phosphate, and reduced iron powder 4 passing through a 240 mesh screen 0.5% by weight, zinc stearate 0.5% by weight as a lubricant, and electrolytic copper powder passing through a 150 mesh sieve are put into a V-type mixer and mixed for 30 minutes to obtain a mixed powder ( Example 1: 9% by weight of tin, 1.5% by weight of magnesium pyrophosphate, 4.5% by weight of iron, 0.5% by weight of zinc stearate, 84.5% by weight of copper, Example 2: 9% by weight of tin, Magnesium pyrophosphate 3 wt%, iron 4.5 wt%, zinc stearate 0.5 wt%, copper 83 wt%, Example 3: tin 9 wt%, magnesium pyrophosphate 5 wt%, iron 4.5 wt% Zinc stearate 0. Wt%, copper 81 wt%,). These mixed powders are 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 4-6
9% by weight of atomized tin powder passing through a 250 mesh screen, 1.5-5% by weight of calcium pyrophosphate or trialuminum phosphate passing through a 200 mesh screen as inorganic phosphate, and passing through a 250 mesh screen 4.5% by weight of pulverized manganese powder, 0.5% by weight of zinc stearate as a lubricant, and electrolytic copper powder with the remainder passing through 150 mesh are put into a V-type mixer, mixed for 30 minutes, and mixed powder (Example 4: tin 9% by weight, calcium pyrophosphate 1.5% by weight, manganese 4.5% by weight, zinc stearate 0.5% by weight, copper 84.5% by weight, Example 5: tin 9 % By weight, calcium pyrophosphate 3% by weight, manganese 4.5% by weight, zinc stearate 0.5% by weight, copper 83% by weight, Example 6: tin 9% by weight, calcium pyrophosphate 5% by weight, Cancer 4.5 wt%, 0.5 wt% of zinc stearate, copper 81 wt%,). These mixed powders were loaded into a hollow part of a mold similar to that in the above-described example, and molded at a molding pressure of 2 ton / cm ² to obtain a square molded 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, 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 7-10
5% by weight of atomized tin powder passing through a 250 mesh screen and 50% by weight of copper-30% nickel alloy powder passing through a 200 mesh screen or 50% by weight of copper-30% nickel alloy powder passing through a 200 mesh screen And electrolytic copper powder with the remainder passing through a 150 mesh sieve, magnesium pyrophosphate 1.5-7% by weight passing through a 200 mesh sieve as an inorganic phosphate, and zinc stearate 0.5 weight as a lubricant % Was added to a V-shaped mixer and mixed for 30 minutes to obtain a mixed powder (Example 7: tin 5% by weight, zinc 15% by weight, magnesium pyrophosphate 1.5% by weight, zinc stearate 0.5% % By weight, copper 78.0% by weight, Example 8: tin 5% by weight, nickel 15% by weight, magnesium pyrophosphate 3% by weight, zinc stearate 0.5% by weight, copper 76.5% by weight Example 9: 5% by weight of tin, 15% by weight of nickel, 5% by weight of magnesium pyrophosphate, 0.5% by weight of zinc stearate, 74.5% by weight of copper, Example 10: 5% by weight of tin, 15% by weight of nickel , Magnesium pyrophosphate 7% by weight, zinc stearate 0.5% by weight, copper 72.5% by weight). These mixed powders were 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 3.5 ton / cm ² . A square shaped green compact was obtained. This molded green compact was sintered at a temperature of 910 ° C. for 60 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.

Comparative Example 1
9% by weight of atomized tin powder passing through a 250 mesh sieve, 6% by weight of pulverized manganese powder passing through a 250 mesh sieve, 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 passing through a 150 mesh sieve are put into a V-type 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
7% by weight of atomized tin powder passing through a 250 mesh screen, 30% by weight of atomized copper-30% zinc alloy powder passing through a 200 mesh screen, 2% by weight of natural graphite powder having an average particle size of 40 μm, and a lubricant As an example, 0.5 wt% of zinc stearate and electrolytic copper powder passing through a 150 mesh screen are put into a V-type mixer and mixed for 30 minutes to obtain a mixed powder (7 wt% tin, 9 zinc) Weight%, graphite 2 weight%, zinc stearate 0.5 weight%, copper 81.5 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.

  For the copper-based oil-impregnated sintered sliding members of Examples 1 to 6 and Comparative Example 1 described above, the friction and wear characteristics were tested under the test conditions shown in Table 1.

  The above-described copper-based oil-impregnated sintered sliding members of Examples 7 to 10 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.

  The test results under the test conditions in Table 1 are shown in Table 3, and the test results under the test conditions in Table 2 are shown in Table 4.

  The value of the friction coefficient in Table 3 indicates the value of the friction coefficient in the stable region after sliding, and the amount of wear (μm) indicates the dimensional change of the copper-based oil-impregnated sintered sliding member after 20 hours of the test time. It was. In addition, since the friction coefficient of the copper-based oil-impregnated sintered sliding member of Comparative Example 1 rapidly increased in the test time of 8 hours, the test was stopped, and the wear amount of the copper-based oil-impregnated sintered sliding member at the end of the test The dimensional change was shown.

  The coefficient of friction in Table 4 indicates the value of the coefficient of friction in the stable region after sliding, and the amount of wear (μm) indicates the dimensional change of the copper-based oil-impregnated sintered sliding member after 20 hours of test time. Indicated. Note that the friction coefficient of the copper-based oil-impregnated sintered sliding member of Comparative Example 2 in Table 4 suddenly increased after 18 hours in the test time, so the test was stopped, and the wear amount was the copper-based oil-impregnated sintered at the end of the test. The dimensional change amount of the sliding member is shown.

  From the test results, the copper-based oil-impregnated sintered sliding members of Examples 1 to 10 that do not contain a solid lubricant such as graphite were compared with Comparative Example 1 and Comparative Example 1 containing graphite as a solid lubricant in terms of friction coefficient and wear amount. The sliding characteristics superior to those of the copper-based oil-impregnated sintered sliding member of Example 2 were exhibited. In the copper-based oil-impregnated sintered sliding members of Examples 1 to 10, the friction coefficient showed a slightly high value at the beginning of sliding, but decreased with the lapse of the test time, and in the stable region, the friction coefficient (very low) 0.02 to 0.06). This confirms that a thin film 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 10. This is presumed to be due to the transition to sliding through this film.

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

Claims (3)

  A sintered matrix body comprising 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 A copper-based oil-impregnated sintered sliding member, wherein inorganic phosphate is dispersed and contained at a ratio of 0.5 to 10% by weight and the pores are impregnated with lubricating oil.   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 lubricating oil is impregnated in the 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.