JP2018054107A - Slide member and manufacturing method therefor - Google Patents

Abstract

The present invention provides a sliding member that has excellent wear resistance, can maintain sliding performance for a long period of time, can reduce the attacking property against the counterpart material, and can prevent damage to the counterpart material, and a method for manufacturing the same. A sliding member including a backing metal layer and a lining layer provided on one surface of the backing metal layer to form a sliding surface, the lining layer being located on the backing metal layer side. A first sintered metal layer and a second sintered metal layer positioned on the sliding surface side, wherein the porosity of the first sintered metal layer is the porosity of the second sintered metal layer Higher sliding member. [Selection] Figure 1

Description

  The present invention relates to a sliding member and a method for manufacturing the same, and more particularly, has excellent wear resistance, can maintain sliding performance for a long period of time, and suppresses the attack on the counterpart material to prevent the counterpart material from being damaged. The present invention relates to a sliding member to be obtained and a manufacturing method thereof.

  Conventionally, in various machines such as construction machines and automobiles, a sliding member such as a slide bearing has been used in order to enable rotation of a shaft inserted into a housing, and a technique related thereto is also disclosed (for example, (See Patent Document 1).

  The sliding member includes, for example, a bush having a back metal layer and a lining layer, and the bush is made of a bimetallic sintered alloy formed by sintering metal powder on the surface of the back metal layer. Bonding gold forms a lining layer. Moreover, the sliding member provided with this bush is used as a slide bearing in, for example, a fuel injection pump, an engine, a transmission, a shock absorber, and the like. The plain bearing has a cylindrical shape, and a cylindrical mating shaft is supported by a hollow portion formed in the inside thereof.

  As a technique for forming a bush with a bimetallic sintered metal, for example, Patent Document 2 discloses a back metal plate, a Fe-based sintered sliding material layer sintered and bonded on the back metal plate, and the Fe-based sintered material. A bushing comprising: a diffusion layer of Fe-based alloy grains formed in the vicinity of the joint interface between the sliding material layer and the back metal plate; and a Cu alloy phase formed in the vicinity of the joint interface and extending toward the joint interface. Has been proposed.

  Further, as other Fe-based sintered alloys, those made of Fe powder, Cu—Fe—Mn alloy powder, Co—Mo—Cr—Si superalloy powder, and C powder are also known (for example, Patent Documents). 3).

JP 2007-333185 A International Publication No. 2007/086861 JP2012-162771 A

However, when the sliding member of the prior art is used for a bearing to which a large surface pressure is applied, such as for a construction machine, the wear resistance is insufficient, and improvement has been demanded. In the technique of Patent Document 3, Fe powder and C powder react in the sintering process and high hardness free cementite (Fe ₃ C) precipitates in the sintered structure, which attacks the counterpart material (shaft). There is a problem of damage.

  Accordingly, an object of the present invention is to provide a sliding member that is excellent in wear resistance and can maintain sliding performance for a long period of time, and that can reduce the attack on the counterpart material and prevent damage to the counterpart material, and a method for manufacturing the same. There is.

  As a result of intensive studies, the present inventor has made a lining having a plurality of layers in a sliding member provided with a lining that forms a sliding surface on a back metal, and determines the porosity of each layer to a specific relationship. As a result, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention is as follows.
[1] A sliding member including a backing metal layer and a lining layer provided on one surface of the backing metal layer to form a sliding surface, wherein the lining layer is located on the backing metal layer side. One sintered metal layer and a second sintered metal layer located on the sliding surface side, wherein the porosity of the first sintered metal layer is greater than the porosity of the second sintered metal layer A sliding member characterized by being high.
[2] The sliding according to [1], wherein a difference between a porosity of the first sintered metal layer and a porosity of the second sintered metal layer is 5% or more. Element.
[3] The above-mentioned [1], wherein the porosity of the first sintered metal layer is 30 to 40%, and the porosity of the second sintered metal layer is 10 to 25%. Or the sliding member as described in [2].
[4] A method for producing the sliding member according to any one of [1] to [3], wherein the first metal powder is dispersed and dispersed on one surface of the back metal layer. A first sintering step of sintering the first metal powder to form a first sintered metal layer; and a second metal powder is sprayed on the first sintered metal layer, and the second metal And a second sintering step of forming a second sintered metal layer by densifying the powder and sintering the densified second metal powder.
[5] The sliding according to [4], wherein the densification of the second metal powder is performed by at least one method selected from the group consisting of the following (1) to (3). Manufacturing method of member.
(1) Method of applying vibration after spraying second metal powder on first sintered metal layer (2) Second metal after spraying second metal powder on first sintered metal layer Method of pressing powder (3) Method of degassing after spraying second metal powder on said first sintered metal layer [6] Sliding according to any one of [1] to [3] A slide bearing comprising a moving member.

According to the present invention, the lining layer is composed of at least a first sintered metal layer and a second sintered metal layer, and the porosity of the first sintered metal layer is higher than the porosity of the second sintered metal layer. Because it is high, the hard and dense second sintered metal layer is resistant to the initial severe wear, and after the initial wear has progressed, the first sintered metal layer having a high porosity and containing a large amount of lubricating oil is used as the lubricating oil. Is supplied to the sliding surface, and friction can be reduced over a long period of time. In addition, the first sintered metal layer having a high porosity is easily plastically deformed when a large surface pressure is applied, and can reduce the aggression against the counterpart material.
Therefore, according to the present invention, there is provided a sliding member that is excellent in wear resistance and that can maintain sliding performance for a long period of time, and that can reduce the attack on the counterpart material and prevent damage to the counterpart material, and a method for manufacturing the same. be able to.

It is a conceptual diagram which shows the external appearance of the sliding member which concerns on embodiment. It is the figure which showed the process of step S01-step S04 in the manufacturing method of the sliding member which concerns on embodiment. It is the figure which showed the process of step S05-step S07 in the manufacturing method of the sliding member which concerns on embodiment. (A) And (b) is the figure which showed the manufacturing method of the color which concerns on another Example, respectively. Is 3 is a photograph of a cross-sectional observation of a lining layer of a sliding member obtained in Example 1. FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view of a sliding bearing 40 that is a sliding member of the embodiment. The slide bearing 40 has a cylindrical outer shape. A lining layer 11, a back metal layer 15, a collar are arranged along a radial direction from an inner peripheral surface (inner side) 7 to an outer peripheral surface (outer side) 8 as a sliding surface. Thirty three layers are arranged concentrically. The sliding bearing 40 according to the present embodiment is a sliding bearing that is used to enable rotation of a mating shaft (hereinafter also simply referred to as “shaft”) communicated with a housing of various machines such as a construction machine and an automobile (not shown). It is used by being press-fitted into the housing. The shaft passes through a hole formed in the center of the slide bearing 40 and is rotatably supported.

  The lining layer 11 is a member that is in direct contact with the rotating shaft, and rotates while the shaft slides, so that low friction, wear resistance, seizure resistance, and the like are required. The lining layer 11 is a porous metal sintered layer composed of a sintered body (sintered metal) obtained by sintering metal powder.

  In the present invention, the lining layer 11 includes a first sintered metal layer 12 located on the back metal layer 15 side and a second sintered metal layer 13 located on the sliding surface 7 side.

  Examples of the sintered metal constituting the first sintered metal layer 12 include iron-based sintered metal, copper-based sintered metal, and iron-copper alloy-based sintered metal. Among these, iron-based sintered metals are preferable from the viewpoint of increasing the hardness of the lining layer and improving the wear resistance. Examples of the iron-based sintered metal include Cu: 13.5 to 22.5 mass%, Sn: 1.5 to 2.5 mass%, C: 0.5 to 3.0 mass%, and the balance Can be exemplified by metals composed of Fe and inevitable impurities.

  From the viewpoint that the effect of the present invention is improved, the thickness of the first sintered metal layer 12 is, for example, 500 to 1500 μm, and preferably 800 to 1200 μm.

  The porosity of the first sintered metal layer 12 is preferably 30 to 40%. If the porosity of the first sintered metal layer 12 is 30% or more, the first sintered metal layer 12 is easily deformed when a load is applied when sliding with the counterpart shaft. It becomes easy to become familiar with the shaft, and can have excellent wear resistance.

  The porosity can be measured by photographing a cut section of the obtained sliding member with a metal microscope and analyzing the image of the holes.

  As described below, the porosity of the first sintered metal layer 12 can be adjusted by appropriately determining the sintering conditions, the degree of pressure during rolling, and the like.

  Examples of the sintered metal constituting the second sintered metal layer 13 include the various sintered alloys described in the first sintered metal layer 12, and the preferred sintered metals are also the same. In the present invention, the first sintered metal layer 12 and the second sintered metal layer 13 may be the same or different types of sintered alloys.

  From the viewpoint that the effect of the present invention is improved, the thickness of the second sintered metal layer 13 is, for example, 1500 to 2500 μm, and preferably 1200 to 2000 μm.

  In the present invention, the thickness ratio of the first sintered metal layer 12 and the second sintered metal layer 13 is preferably 1: 1 to 1: 5, and more preferably 1: 2 to 1: 3. preferable.

  The porosity of the second sintered metal layer 13 is preferably 10 to 25%. When the porosity of the second sintered metal layer 13 is 10% or more, the lubricating oil necessary for sliding can be sufficiently infiltrated into the lining layer, so that the sliding member has excellent sliding characteristics. be able to. When the porosity is 25% or less, the strength required for the sliding member can be ensured. The porosity of the second sintered metal layer 13 is preferably 15 to 25%.

  As described below, the porosity of the second sintered metal layer 13 is appropriately determined by the sintering conditions, the degree of pressure during rolling, and the means and conditions for densifying the powder for forming the second sintered metal layer. It can be adjusted by doing.

  The sliding member of the present invention is characterized in that the porosity of the first sintered metal layer 12 is higher than the porosity of the second sintered metal layer 13. Since the porosity of the first sintered metal layer 12 is higher than the porosity of the second sintered metal layer 13, the hard and dense second sintered metal layer 13 is resistant to initial severe wear. Further, after the initial wear has progressed, the lubricating oil is supplied to the sliding surface from the first sintered metal layer 12 having a high porosity and containing a large amount of lubricating oil, and it becomes possible to reduce friction over a long period of time. In addition, the first sintered metal layer 12 having a high porosity is easily plastically deformed when a large surface pressure is applied, and can reduce the aggression against the counterpart material.

In the present invention, the difference between the porosity of the first sintered metal layer 12 and the porosity of the second sintered metal layer 13 is preferably 5% or more. If the difference in porosity is less than 5%, the above-described effects may not be achieved.
The difference between the porosity of the first sintered metal layer 12 and the porosity of the second sintered metal layer 13 is more preferably 5 to 10%.

  The thickness of the lining layer 11 may be appropriately adjusted according to the shaft diameter of the desired slide bearing, but is preferably 1.65 to 2.1 mm, for example, when a shaft having a diameter of 80 mm is inserted.

  As shown in FIG. 1, the lining layer 11 has, on its sliding surface 7, a groove 6 for supplying lubricating oil from the outside, and a plurality of recesses (for storing the lubricating oil supplied from the groove 6). Indentation) 5 is preferred. By providing the recess 5, the lubricating oil can be held in the recess 5, so that the sliding performance can be maintained well.

  In the present invention, the lining layer 11 may further include another sintered metal layer between the first sintered metal layer 12 and the second sintered metal layer 13. The porosity and thickness of the other sintered metal layers and the sintered metal constituting the other sintered metal layers are arbitrary, but the porosity is higher than that of the second sintered metal layer 13, and the first sintered metal layer has a higher porosity. It is preferable that the layer is smaller than the bonded metal layer 12.

The back metal layer 15 is made of a plate-like metal member and is a member that receives a load from the shaft. A bimetal constituted by a two-layer structure of the back metal layer 15 and the lining layer 11 constitutes a bush 20 that mainly serves as a sliding member.
As a metal which comprises the back metal layer 15, an iron-type metal etc. are mentioned, for example.

  The thickness of the back metal layer 15 may be adjusted as appropriate according to the shaft diameter of the desired slide bearing. For example, when a shaft having a diameter of 80 mm is inserted, it is preferably 1.85 to 2.15 mm.

In the present invention, when the recess 5 is formed in the bush 20, the back surface of the bush 20, that is, the surface on the back metal layer 15 side may be raised due to the stress of the processing machine (for example, a press machine). Therefore, it is preferable to provide the collar 30 on the back metal layer 15 side of the bush 20.
The collar 30 is formed of a cylindrical metal member, and is a member for maintaining the overall shape of the sliding bearing 40 and fixing the sliding bearing 40 (bush 20) to another member such as a housing. When the bush 20 is press-fitted into the inner surface of the collar 30, the slide bearing 40 is formed.

  Next, the manufacturing method of the sliding member of the present invention will be described in the case of a slide bearing.

  In the method for manufacturing the plain bearing 40 according to the present embodiment, the first metal powder is dispersed on one surface of the back metal layer 15, and the dispersed first metal powder is sintered to form the first sintered metal layer. 12, a second metal powder is dispersed on the first sintered metal layer 12, the second metal powder is densified, and the densified second metal powder is And a second sintering step of forming the second sintered metal layer 13 by sintering. Specifically, as shown in FIGS. 2 and 3, the first powder spreading step (step S01A) and the first sintering step (step S02A), the second powder spreading and densifying step (step S01B) and the second A sintering step (step S02B), a recess forming step (step S03), a bush forming step (step S04), a heat treatment step (step S05), a press-fitting step (step S06), and an oil impregnation / finishing step (step S07). . Hereinafter, each step will be specifically described.

  As shown in FIG. 2, in the first powder spraying step (step S01A), first, a back metal (back metal layer 15), which is a plate-like metal member, is prepared. For example, an iron-based member is used as the material of the back metal layer 15. Next, the 1st metal powder for forming the 1st sintered metal layer 12 is spread | dispersed on the surface 15a of the back metal layer 15 using a spreading | diffusion apparatus, and the spreading | diffusion layer 12a is formed. As the first metal powder, for example, a powder in which iron powder and copper powder are mixed substantially uniformly can be used. Thus, the spreading | diffusion layer 12a is spread | dispersed substantially uniformly on the surface of the plate-shaped back metal layer 15, and the plate-shaped pre-sintering member 10a is comprised. The average particle diameter of the first metal powder is, for example, Fe: 120 μm, CuSn: 60 μm, C: 15 μm.

Next, in the first sintering step (step S02A) shown in FIG. 2, the pre-sintering member 10a configured in the first powder spraying step (step S01A) is placed in a sintering furnace and heated with a heater and sprayed. The spreading layer 12a is sintered in an atmosphere at a temperature lower than the melting point of the iron powder that is the main component in the layer 12a.
In order to obtain the porosity in the sliding member of the present invention, the sintering temperature in step S02A is, for example, 800 to 1300 ° C., preferably 900 to 1000 ° C., and the sintering time is, for example, 30 ~ 90 minutes, preferably 50-80 minutes.
By this step S02A, the spreading layer 12a becomes the porous first sintered metal layer 12, and also becomes a bimetal of the back metal layer 15 and the first sintered metal layer 12.

  Next, in the second powder spraying / densification step (step S01B), the second metal powder for forming the second sintered metal layer 13 is added as in the first powder spraying step (step S01A). Then, spraying is performed on the first sintered metal layer 12 using a spraying device to form the spraying layer 13a. As the second metal powder, for example, the same metal powder as the first metal powder can be used.

In the second powder dispersion / densification step (step S01B), the dispersion layer 13a is densified. Although it does not specifically limit as a method of densification of the spreading | diffusion layer 13a, It is preferable to carry out by at least 1 method selected from the group which consists of following (1)-(3).
(1) Method of applying vibration after spraying second metal powder on first sintered metal layer (2) Second metal after spraying second metal powder on first sintered metal layer Method of pressing powder (3) Method of degassing after spraying second metal powder on the first sintered metal layer By performing any one of the above methods (1) to (3), the spray layer While removing the air contained in 13a, the space | gap part between powder can be reduced. The porosity of the second sintered metal layer 13 can be adjusted by the degree of densification.
In this step S01B, since the spray layer 13a is densified, the thickness of the spray layer 13a itself may be reduced. In this case, in order to obtain the second sintered metal layer 13 having a desired thickness, it is preferable to increase the thickness of the sprayed layer 13a before densification in consideration of a decrease in the thickness of the sprayed layer 13a itself. .
In this way, the spray layer 13a is sprayed substantially uniformly on the surface of the first sintered metal layer 12 to constitute the plate-like pre-sintering member 10b.

Next, in the second sintering step (step S02B) shown in FIG. 2, the pre-sintering member 10b configured in the second powder dispersion / densification step (step S01B) is placed in a sintering furnace and heated with a heater. And the spreading | diffusion layer 13a is sintered in the atmosphere of temperature lower than melting | fusing point of the iron powder which is a main component in the spreading | diffusion layer 13a.
In order to obtain the porosity in the sliding member of the present invention, the sintering temperature in step S02B is, for example, 800 to 1300 ° C., preferably 900 to 1000 ° C., and the sintering time is, for example, 30 ~ 90 minutes, preferably 50-80 minutes.
By this step S02B, the spreading layer 13a becomes the porous second sintered metal layer 13, and the sintered alloy made of the bimetal of the back metal layer 15, the first sintered metal layer 12, and the second sintered metal layer 13. 10

  The bush 20 having a porosity of the first sintered metal layer 12 higher than that of the second sintered metal layer 13 can be formed by the first sintering process and the second sintering process.

  In the present invention, after securing a desired porosity, the sintered metal is used during the first sintering step (step S02A) and / or the second sintering step (step S02B) or after these steps. May be rolled with a roller or the like. By performing the rolling process, the rising layer can have a desired thickness.

  Subsequently, the recess forming step (step S03) shown in FIG. 2 is performed. In step S <b> 03, a plurality of recesses 5 are formed in the lining layer 11. The formation method of the recessed part 5 is not specifically limited, A press work, cutting, etc. are mentioned.

  Next, in the bushing forming step (step S04) shown in FIG. 2, the sintered alloy 10 formed in steps S01 to S03 is bent by a press machine or the like so that the lining layer 11 is on the inner side, and is cylindrical. A shaped bush 20 is formed. By this bush forming step, the inner peripheral surface of the bush 20 that will later become the inner peripheral surface of the sliding bearing 40 which is a sliding member is formed.

  Next, in the heat treatment step shown in FIG. 3 (step S05), the bushing 20 is subjected to heat treatment such as carburizing and quenching to perform lining hardening and surface modification of the bushing 20. By this treatment, the hardness of each of the backing metal layer 15 and the lining layer 11 is improved (for example, the backing metal layer 15 has a Vickers hardness of 100 to 400, the first sintered metal layer 12 has a Vickers hardness of 650 to 800, and a second firing. The binder metal layer 13 has a Vickers hardness of 400 to 650) and the strength of the bushing 20 is improved.

  Next, in the press-fitting process (step S06) shown in FIG. 3, the bush 20 subjected to the heat treatment is press-fitted into the collar 30 which is a cylindrical metal member (for example, an iron-based member) to form the slide bearing 40. Since the collar 30 is not heat-treated like the bush 20, its hardness is smaller than that of the backing metal layer 15 (for example, Vickers hardness 100 to 200). Further, the inner diameter dimension of the collar 30 is formed to be the same as or slightly smaller than the outer diameter dimension of the bush 20 so that the bush 20 can be press-fitted. By this press-fitting process, the outer peripheral surface of the collar 30 that will later become the outer peripheral surface of the sliding bearing 40 that is a sliding member is formed.

  Next, in the oil-impregnating / finishing step (step S07) shown in FIG. 3, the sliding bearing 40 is impregnated with an oil component made of high-viscosity lubricating oil using an oil-impregnating machine. In the oil impregnation step, the high-viscosity lubricating oil is heated to lower the viscosity, and the slide bearing 40 is immersed in the lubricating oil and left in a vacuum atmosphere. As a result, the air in the pores of the slide bearing 40 is sucked out of the pores, and the low-viscosity lubricating oil is sucked into the pores of the slide bearing 40. When the sliding bearing 40 that has sucked the lubricating oil is taken out into the air and allowed to cool to room temperature, the lubricating oil whose viscosity has been lowered returns to the original high-viscosity lubricating oil within the pores of the sliding bearing 40 and loses fluidity. Thereby, high-viscosity lubricating oil can be kept in the pores of the slide bearing 40.

  As described above, in the sliding bearing 40 that is the sliding member according to the present embodiment, the lining layer 11 is formed on the surface of the back metal layer 15 that is a plate-like metal member by the first sintering process and the second sintering process. By being formed, a bimetallic sintered alloy 10 is formed. In the present invention, since the densification treatment is performed before the metal powder is sintered in the second sintering step, the lining layer 11 is composed of two layers having different airport ratios. Then, the sintered alloy 10 is formed as a cylindrical bush 20, and after the heat treatment is performed on the bush 20, the bush 20 is press-fitted into a collar 30 that is a cylindrical metal member to form the plain bearing 40. . That is, as shown in FIG. 1, the plain bearing 40 according to the present embodiment includes three layers of the lining layer 11, the back metal layer 15, and the collar 30 from the inside to the outside. That is, the plain bearing 40 is configured by the bush 20 and the collar 30 provided around the bush 20.

  By configuring as described above, when the slide bearing 40 is press-fitted into the housing, the outer peripheral surface of the slide bearing 40 is less likely to be galling. Specifically, since the collar 30 disposed on the outer periphery of the slide bearing 40 is not subjected to heat treatment, the hardness of the collar 30 is smaller than that of the back metal layer 15 and the like. For this reason, when the slide bearing 40 is press-fitted into the housing, the occurrence of galling can be suppressed at the portion of the collar 30 that comes into contact with the housing.

  Further, the overall hardness of the slide bearing 40 can be suppressed by arranging the collar 30 that has not been heat-treated in the outer peripheral portion. Thereby, the strong hit which the slide bearing 40 generate | occur | produces locally can be reduced, seizure resistance and wear resistance can be improved, and it can make it hard to produce a crack.

  In addition, even when the slide bearing 40 having a large thickness (radial thickness) is formed, the radial thickness of the collar 30 may be adjusted, and the thickness of the sintered alloy 10 can be made constant. For this reason, even when the slide bearing 40 has a large thickness, it can be easily molded.

  Furthermore, according to the present embodiment, the sintered alloy 10 is formed from the plate-like pre-sintering member 10b, and the bush 20 is formed by bending the sintered alloy 10, so that only the sintered material is formed. Thus, it is not necessary to form a cylindrical part and can be easily processed. In addition, since it is not necessary to press-fit only the highly brittle sintered material into the back metal layer, cracks do not occur when the sintered material is pressed into the back metal layer.

  In addition, since the groove or the concave portion can be formed by the groove processing or the concave portion (indent) processing at the stage of the plate-like sintered alloy 10, the groove or the concave portion is easily formed on the inner peripheral surface of the slide bearing 40. Thus, the sliding characteristics on the inner peripheral surface of the slide bearing 40 can be improved.

  As described above, according to the present embodiment, the slide bearing 40 is formed such that when it is press-fitted into the housing, the collar 30 that is the back metal part of the slide bearing 40 is less likely to be galvanized, is not easily cracked, and is easy to form grooves, recesses, and the like. It can be manufactured.

  In addition, the “collar 30 which is a cylindrical metal member” of the present invention can be formed by cutting from a pipe material or a solid material, or the end portions of a plate-shaped (band-shaped) member are butted together (rolled). ) May be formed, and can be appropriately selected in terms of cost and equipment. However, it is preferable to create a cylindrical shape from a plate-like member because a collar can be produced at a lower cost. In that case, finish processing is performed with the seam closed in order to provide a tightening allowance. Furthermore, when a collar is formed by winding a plate-like member, not only the joints may be joined by welding, but they may be joined in a clinch shape.

  Hereinafter, the case where the collar 30 is formed from a plate-like member and is joined in a clinch shape will be described with reference to FIG. Specifically, as shown in FIG. 4A, a plate-like member having clinch shapes (substantially circular engaging convex portions 17a and engaging concave portions 17b at both ends is wound by a bending machine or the like not shown. Then, the bending member 17c having a semi-cylindrical central portion is formed, and the radius of curvature of the inner peripheral surface of the bending member 17c is substantially the same as or slightly larger than the radius of curvature of the outer peripheral surface of the bushing 20. The outer surface of the bending member 17c formed by this rough bending step is the outer peripheral surface of the collar 30, that is, the outer peripheral surface of the slide bearing 40.

  Next, as shown in FIG. 4B, the central portion (semi-cylindrical portion) of the bending member 17c is set on the side of the upper die 52s which is a semi-cylindrical fixed die. Then, the lower mold 52m, which is also a semi-cylindrical movable mold, is brought close to the end of the bending member 17c as indicated by an arrow U shown in FIG. 4B. Thereby, the clinch shape is engaged by deforming both side ends of the bending member 17c, which is a plate-like member, along the semi-cylindrical surface of the lower mold 52m. Specifically, both end portions of the bending member 17c, which is a plate-like member, are joined by causing the engaging convex portion 17a to enter and engage with the engaging concave portion 17b. In this way, the collar 30 that is the outer member is formed. Thereafter, the bush 20 is press-fitted into the cylindrical collar 30 to form the slide bearing 40.

According to the sliding member of the present invention, the lining layer 11 is composed of at least the first sintered metal layer and the second sintered metal layer, and the porosity of the first sintered metal layer is that of the second sintered metal layer. Since it is higher than the porosity, when a large surface pressure is applied, the first sintered metal layer is easily plastically deformed, and the aggressiveness against the counterpart material can be reduced. Further, since the second sintered metal layer is hard and dense, it has resistance to initial wear. After the initial wear progresses, the lubricating oil is supplied to the sliding surface from the first sintered metal layer having a high porosity and containing a large amount of lubricating oil, and friction can be reduced over a long period of time.
Therefore, according to the present invention, there is provided a sliding member that is excellent in wear resistance and that can maintain sliding performance for a long period of time, and that can reduce the attack on the counterpart material and prevent damage to the counterpart material, and a method for manufacturing the same. be able to.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not restrict | limited to the following example.

Example 1
The sliding member of the present invention was manufactured according to the manufacturing method shown in FIG.
First, a back metal layer 15 which is a plate-shaped metal member (iron-based member) is prepared, and a first metal powder (C: 1.5 mass) having an average particle diameter of Fe: 120 μm, CuSn: 60 μm, C: 15 μm. %, Cu: 16.2% by mass, Sn: 1.8% by mass, the balance being Fe) using a spraying device to spray the surface of the back metal layer 15 to form a sprayed layer 12a with a thickness of 0.7 mm, A plate-like pre-sintering member 10a was obtained.
Subsequently, the pre-sintering member 10a was placed in a sintering furnace and heated and sintered at a sintering temperature of 950 ° C. for 60 minutes to form the first sintered metal layer 12.

Next, on the surface of the first sintered metal layer 12, a second metal powder having the same configuration as the first metal powder is dispersed using a spraying device to form a sprayed layer 13a having a thickness of 1.2 mm. As a result, a plate-like pre-sintering member 10b was obtained.
Thereafter, the dispersion layer 13a was densified by applying vibration to the pre-sintering member 10b for 300 seconds.
Subsequently, the pre-sintering member 10b having the densified spreading layer 13a was placed in a sintering furnace and heated and sintered at a sintering temperature of 950 ° C. for 60 minutes to form the second sintered metal layer 13.

  The sliding member which has a lining layer whose thickness of the 1st sintered metal layer 12 and the 2nd sintered metal layer 13 is 500 micrometers and 1000 micrometers, respectively by the above process was obtained.

The cut section of the obtained sliding member was photographed with a metal microscope, and the porosity of the first sintered metal layer and the second sintered metal layer in the lining layer was measured by image analysis.
The porosity of the first sintered metal layer was 30%, and the porosity of the second sintered metal layer was 15%. Moreover, the photograph figure of the cross-sectional observation of a lining layer is shown in FIG.

  From the above results, in the sliding member of Example 1, the porosity of the first sintered metal layer 12 is higher than the porosity of the second sintered metal layer 13. It was found that the difference between the porosity and the porosity of the second sintered metal layer 13 was 15%.

  The sliding member of the present invention is particularly suitably used as a slide bearing.

5 Recess 6 Groove 7 Inner peripheral surface (sliding surface)
8 Outer peripheral surface 11 Lining layer 12 First sintered metal layer 13 Second sintered metal layer 15 Back metal layer 20 Bush 30 Color 40 Slide bearing (sliding member)

Claims (6)

A sliding member provided with a backing metal layer and a lining layer provided on one surface of the backing metal layer to form a sliding surface,
The lining layer includes a first sintered metal layer located on the back metal layer side, and a second sintered metal layer located on the sliding surface side,
The sliding member, wherein the porosity of the first sintered metal layer is higher than the porosity of the second sintered metal layer.   The sliding member according to claim 1, wherein a difference between a porosity of the first sintered metal layer and a porosity of the second sintered metal layer is 5% or more.   The porosity of the first sintered metal layer is 30 to 40%, and the porosity of the second sintered metal layer is 10 to 25%. The sliding member. A method for producing the sliding member according to any one of claims 1 to 3,
A first sintering step of spreading a first metal powder on one side of the back metal layer and sintering the dispersed first metal powder to form a first sintered metal layer;
A second metal powder is dispersed on the first sintered metal layer, the second metal powder is densified, and the densified second metal powder is sintered to form a second sintered metal layer. And a second sintering step to be formed. The method for producing a sliding member according to claim 4, wherein the densification of the second metal powder is performed by at least one method selected from the group consisting of the following (1) to (3). .
(1) Method of applying vibration after spraying second metal powder on first sintered metal layer (2) Second metal after spraying second metal powder on first sintered metal layer Method of pressing powder (3) Method of degassing after spraying second metal powder on said first sintered metal layer   A sliding bearing comprising the sliding member according to claim 1.