Sliding member, gearbox using the same, wind turbine, and method for manufacturing sliding member

Abstract

This sliding member comprises a base material, and a sliding layer that is stacked on the base material and has a matrix and a particle phase dispersed uniformly and finely in the matrix. An arbitrary observation cross-section of the sliding layer is set, and an area ratio Sv of the particle phase in a plurality of arbitrary observation regions extracted from the observation cross-section is 0.2% ≤ Sv ≤ 5％ in each of the observation regions. The maximum particle diameter Da of the particle phase is 0 μm < Da ≤ 30 μm.

Description

Cross-reference to Related Applications

[0001] This application is based on Japanese Application No. 2022-056211 filed on Mar. 30, 2022, the content of which is incorporated herein by reference.

Technical Field

[0002] The present disclosure relates to a sliding member, a gearbox, a wind turbine using the same, and a method for manufacturing the sliding member.

Background Art

[0003] Conventionally, it is well known to form a sliding member by arc welding (Patent Document 1). In Patent Document 1, an alloy of Cu-Sn-Pb is laminated as a sliding layer on the surface of a backing metal by arc welding. At this time, the sliding layer is formed using a powder in which Pb is previously dispersed in the matrix of the alloy. Thereby, in Patent Document 1, evaporation of Pb due to high temperature during welding is reduced, and formation of a structure in which Pb is uniformly dispersed in the sliding layer is attempted.

[0004] In recent years, due to demands such as further reduction of the environmental load, bearings using sliding members are required to improve sliding characteristics in a high surface pressure environment. Therefore, for example, a low melting point metal or a hard material is added to the matrix as an additive to improve the properties of the sliding layer. In this case, the sliding layer can be formed, for example, by performing welding using a powder or wire in which an additive has been previously added to the matrix.

[0005] However, a low melting point metal added to the matrix is likely to evaporate during welding, causing problems such as defects and segregation in the matrix of the sliding layer. In addition, a hard material added to the matrix is likely to agglomerate during welding, making it difficult to achieve uniform dispersion in the matrix. Non-uniform distribution of hard particles in the sliding layer causes problems such as a decrease in the strength of the sliding layer and deterioration of the sliding characteristics.

Prior Art Documents

Patent Documents

[0006] Patent Document 1 Japanese Patent Application Laid-Open No. 04-300073 Summary of the Invention

[0007] Therefore, an object of the present disclosure is to provide a sliding member in which particles of an additive are uniformly dispersed in a sliding layer, the sliding characteristics are high without impairing the strength, and a gearbox and a wind turbine using the same. Another object of the present disclosure is to provide a method for manufacturing a sliding member that reduces evaporation of an additive, achieves uniform dispersion of the additive, and further improves sliding characteristics.

[0008] A sliding member according to an embodiment of the present disclosure includes a base material and a sliding layer laminated on the base material and having a matrix and a particle phase uniformly and finely dispersed in the matrix. That is, in the sliding member of one embodiment, in a plurality of arbitrary observation regions extracted from an arbitrary observation cross section, the area ratio Sv of the particle phase is 0.2% ≤ Sv ≤ 5% in all cases. Thus, in the sliding member of one embodiment, the particle phase is uniformly present in the matrix of the sliding layer. And the maximum particle diameter Da of the particle phase is refined to 0 μm < Da ≤ 30 μm. Therefore, the particles of the additive are uniformly and finely dispersed in the sliding layer, and the sliding characteristics can be enhanced without impairing the strength. In particular, the sliding member of one embodiment can enhance seizure resistance and abrasion resistance.

[0009] A method for manufacturing a sliding member according to an embodiment of the present disclosure forms a sliding layer by arc welding a wire to a base material. This method for manufacturing a sliding member includes a step of supplying the wire that becomes the matrix constituting the sliding layer, a step of melting the supplied wire by discharge with the base material to form droplets, and a step of adding an additive to be added to the matrix to the formed droplets.

[0010] As a result, the additive is mixed into the droplets of the melted wire. That is, in this embodiment, the additive is added not to the molten pool formed in the base material by the arc between the base material and the wire, but to the droplets formed in the wire. Therefore, the additive is uniformly and finely dispersed in the droplets, and is also uniformly and finely dispersed in the sliding layer formed by the solidification of the droplets. This is because the droplets are rapidly cooled when they fall onto the base material. That is, the additive added to the droplets is uniformly and finely mixed with the relatively small-volume droplets, then falls onto the base material and is cooled, and solidifies while maintaining the uniformly and finely mixed state. Also, by adding the additive to the droplets, the mixing of the base material and the additive is reduced compared to the case of adding the additive to the molten pool. Furthermore, by adding the additive to droplets with a relatively small heat capacity as in this embodiment, the additive is rapidly cooled while remaining dispersed in the droplets, and defects caused by the evaporation of the additive are also reduced. Therefore, further improvement in sliding performance can be achieved.

[0011] In the manufacturing method of the sliding member according to another embodiment, the additive added to the matrix is added to the droplets as particles, powder containing the particles, wire containing the particles, or bar containing the particles.

Brief Description of the Drawings

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[0013] Hereinafter, embodiments will be described with reference to the drawings. (Welding apparatus) First, a welding apparatus for manufacturing a sliding member will be described. As shown in FIG. 1, the welding apparatus 10 is a so-called arc welding apparatus that uses electric discharge between the base material 11 and the wire 12. The welding apparatus 10 includes a wire supply unit 13. The wire supply unit 13 supplies the wire 12, which is a consumable electrode, to the base material 11 side periodically while repeating movement to the base material 11 side and movement to the opposite side at a preset cycle and movement amount. Between the wire supply unit 13 and the base material 11, they are electrically connected through a power supply device 14. The power supply device 14 applies a preset voltage between the wire supply unit 13 and the base material 11. When the wire 12 contacts the wire supply unit 13, it has the same potential as the wire supply unit 13. As a result, when the base material 11 and the wire 12 approach, an arc state occurs, and when the base material 11 and the wire 12 contact, a short-circuit state occurs. By advancing and retracting the wire 12 by the wire supply unit 13, an arc state and a short-circuit state repeatedly occur between the base material 11 and the wire 12.

[0014] When the tip of the wire 12 approaches the base material 11 by the wire supply unit 13, an arc is generated between the wire 12 and the base material 11. The wire 12 is instantaneously heated and melted by the generated arc. The melted wire 12 becomes a molten droplet 15 and falls toward the base material 11 side. When the molten droplet 15 of the melted wire 12 contacts the base material 11, the base material 11 and the wire 12 are short-circuited and the energization between the base material 11 and the wire 12 stops, and the molten droplet 15 migrates to the base material 11. That is, the wire 12 is laminated on the base material 11 by droplet transfer by arc welding. When the wire supply unit 13 moves the tip of the wire 12 away from the base material 11, the base material 11 and the wire 12 are separated, and an arc is generated again between the base material 11 and the wire 12. By repeating this, a weld layer is formed on the base material 11 from the material constituting the wire 12.

[0015] The wire supply unit 13 has a gas ejection port 16. The wire supply unit 13 ejects a shielding gas 17 from the gas ejection port 16. The shielding gas 17 mainly consists of an inert gas such as argon or helium, and oxygen or the like is added thereto. The gas ejection port 16 ejects the shielding gas 17 so as to surround the vicinity of the welding part where the base material 11 and the wire 12 come into contact. Thereby, the welding part between the base material 11 and the wire 12 is shielded from the outside air by the shielding gas 17. As the shielding gas 17, Ar containing O2, 100% Ar, CO2, Ar + CO2, Ar + He, etc. can be used.

[0016] In addition to the above, the welding apparatus 10 includes a filler supply unit 20. The filler supply unit 20 supplies a filler 21 to the molten droplet 15 formed by the arc between the base material 11 and the wire 12. In the present embodiment, the filler supply unit 20 supplies the filler 21 to the molten droplet 15 formed on the wire 12 side, rather than to the molten pool formed on the base material 11 side by the arc between the base material 11 and the wire 12. As shown in FIG. 1, the filler supply unit 20 supplies the powdery filler 21 to the molten droplet 15. Further, the filler supply unit 20 may be configured to supply a wire 22 containing the filler 21 to the molten droplet 15 as shown in FIG. 2. Furthermore, the filler supply unit 20 is not limited to the examples shown in FIGS. 1 and 2, and may be configured to supply a rod or the like containing the filler 21 to the molten droplet 15.

[0017] As described above, in the case of the present embodiment, the welding apparatus 10 includes the filler supply unit 20. Therefore, the filler 21 is supplied to the molten droplet 15 formed by melting the wire 12 by the arc between the base material 11 and the wire 12.

[0018] (Method for manufacturing a sliding member, sliding member) Next, a method for manufacturing a sliding member using the above welding apparatus and the sliding member obtained thereby will be described. As shown in FIG. 3, the sliding member 30 includes a base material 11 and a sliding layer 32. The sliding member 30 slides against a mating member (not shown). The mating member is formed of, for example, an Fe-based material such as steel or stainless steel. The sliding layer 32 forms a sliding surface 33 on the surface opposite to the base material 11. The base material 11 is formed of, for example, a metal such as Fe or Cu or an alloy thereof. The sliding layer 32 is formed on the surface of the base material 11 by welding. Specifically, as shown in FIG. 1, the sliding layer 32 is formed mainly of the wire 12 by welding the wire 12 to the base material 11. The sliding layer 32 is an alloy having an element among Cu, Al, and Sn as a first component. That is, the matrix of the alloy constituting the sliding layer 32 is formed by the wire 12. The first component is the one having the highest content rate in the alloy constituting the sliding layer 32. For example, when the sliding layer 32 is formed of a Cu alloy, the wire 12 is formed of the same Cu alloy as this sliding layer 32.

[0019] As shown in FIG. 4, the sliding layer 32 has a particle phase 35 uniformly and finely dispersed in a matrix 34. That is, the sliding layer 32 has a matrix 34 and a particle phase 35 uniformly and finely dispersed in this matrix 34. The particle phase 35 contains a high-hardness phase. The high-hardness phase is a phase of particles having a higher hardness than the matrix 34. The high-hardness phase is, for example, at least one or more elements or compounds selected from Ni, Sn, Mo, C, B, Si, Mn, Fe, P, Ti, Al, W, Cr, Sc, Zr, Co, Cu, etc., or a compound of these with O, N, etc.

[0020] When the Vickers hardness of the high-hardness phase constituting the particle phase 35 is HV1 and the Vickers hardness of the matrix 34 is HV2, there is a relationship of 5 ≦ HV1 / HV2 ≦ 50 between them. That is, the high-hardness phase constituting the particle phase 35 has a Vickers hardness HV 5 to 50 times that of the matrix 34. Thus, by setting the hardness of the high-hardness phase with respect to the matrix 34, it is possible to improve seizure resistance and wear resistance while reducing the aggressiveness to the mating member.

[0021] Further, the particle phase 35 may contain a low-hardness phase. The low-hardness phase is a phase of particles with a hardness lower than that of the matrix 34. The low-hardness phase is, for example, at least one element selected from Pb, Bi, Sn, Sb, In, Mg, Al, Zn, etc., or a compound thereof. In this case, in a plurality of observation regions set in an arbitrary observation cross-section, the area ratio Sv of the particle phase 35 is 0.2% ≤ Sv ≤ 5%. The particle phase 35 is uniformly dispersed in the matrix 34 of the sliding layer 32. And the maximum particle diameter Da of the particle phase 35 is refined to 0 μm < Da ≤ 30 μm. Therefore, the particle phase 35 can be uniformly and finely dispersed in the sliding layer 32, and the sliding characteristics can be improved without impairing the strength of the sliding layer 32. In particular, as the sliding characteristics of the sliding layer 32, seizure resistance and wear resistance can be improved.

[0022] Also, the low-hardness phase among the particle phases 35 may coexist with the high-hardness phase. In this case, the high-hardness phase and the low-hardness phase may be uniformly and finely present in the matrix 34 of the sliding layer 32. Further, while the high-hardness phase is configured to be uniformly and finely present in the matrix 34 of the sliding layer 32, the low-hardness phase may not necessarily be uniformly and finely dispersed in the matrix 34. When the low-hardness phase is not uniformly and finely dispersed in the matrix 34 in this way, the addition amount of the low-hardness phase in the sliding layer 32 is preferably 20 mass% or less. Thus, by setting the addition amount of the low-hardness phase to 20 mass% or less, the influence on the strength of the sliding layer 32 is reduced. Furthermore, the sliding layer 32 may contain a solid lubricant regardless of its hardness. The solid lubricant is, for example, at least one selected from graphite, MoS2, etc. Hereinafter, the particle phase 35 is a general term including the high-hardness phase and the low-hardness phase.

[0023] The wire 12 is supplied to the wire supply unit 13 of the welding apparatus 10 shown in FIGS. 1 and 2. The wire 12 supplied to the wire supply unit 13 is melted by arc discharge with the base material 11 to form droplets 15 as shown in FIGS. 5(A) and 6(A). The formed droplets 15 are added with the additive 21. The additive 21 is added from the additive supply unit 20 to the droplets 15. The additive 21 is added from the additive supply unit 20 to the droplets 15 as particles of a preselected material that become the particle phase 35 as shown in FIG. 5(A), or as a powder containing particles of the material. Further, the additive 21 is added from the additive supply unit 20 to the droplets 15 as a wire 22 containing particles of the material, or as a bar material containing particles of the material as shown in FIG. 6(A).

[0024] The particle phase 35 containing at least one of the low hardness phase and the high hardness phase is formed from the additive 21 supplied from the additive supply unit 20. That is, by adding the additive 21 to the droplets 15 of the melted wire 12, various materials that become the particle phase 35 are mixed into the droplets 15 of the melted wire 12. Then, when the droplets 15 migrate to the base material 11 as shown in FIGS. 5(B) and 6(B), the droplets 15 made of the wire 12 as the material of the matrix 34 are laminated on the base material 11. When the droplets 15 solidify as shown in FIGS. 5(C) and 6(C), a sliding layer 32 is formed on the base material 11.

[0025] The sliding layer 32 may be formed as shown in FIG. 7, not limited to the above example. In the case of the example shown in FIG. 7, the wire 12 supplied to the wire supply unit 13 is melted by the arc discharge between the base material 11, and forms a molten droplet 15 as shown in FIG. 7(A). The formed molten droplet 15 migrates to the base material 11 as shown in FIG. 7(B). In the case of the example shown in FIG. 7, the additive supply unit 20 adds the additive 21 to the molten droplet 15 that has migrated to the base material 11 and is in a molten state as shown in FIG. 7(C). By adding the additive 21 to the molten droplet 15, various materials that will become the particle phase 35 are mixed into the molten droplet 15 of the melted wire 12. Then, as the molten droplet 15 solidifies, a sliding layer 32 is formed on the base material 11. Note that, as shown in FIG. 5 or FIG. 7, the timing at which the additive supply unit 20 adds the additive 21 can be set during the period from when the molten droplet 15 is formed by the arc to when it solidifies on the base material 11.

[0026] These sliding layers 32 contain a particle phase 35 made of the additive 21 as a raw material in the matrix 34 as described above. In the case of the present embodiment, the additive 21 is added to the molten droplet 15 formed on the wire 12, rather than to the molten pool formed on the base material 11 by the arc between the base material 11 and the wire 12 during the formation of the sliding layer 32. As a result, the additive 21 that becomes the particle phase 35 is uniformly and finely dispersed in the molten droplet 15, and is also uniformly and finely dispersed in the formed sliding layer 32. This is because when the molten droplet 15 drops onto the base material 11, the molten droplet 15 is rapidly cooled. That is, the additive 21 added to the molten droplet 15 is uniformly and finely mixed with the relatively small-volume molten droplet 15, then drops onto the base material 11 and is cooled, and solidifies while maintaining the uniformly and finely mixed state.

[0027] Further, by adding the additive 21 to the droplet 15, the mixing with the base material 11 in the sliding layer 32 is reduced as compared with the case of adding the additive 21 to the molten pool. The molten pool is in a state where the wire 12 and the base material 11 are mixed and melted. Therefore, for example, when the additive 21 is added to the molten pool, the additive 21 is mixed not only with the wire 12 that becomes the sliding layer 32 but also with the melted base material 11. Then, the base material 11, the wire 12, and the additive 21 mixed in the molten pool have a slow solidification rate and are likely to cause aggregation of the additive 21. Further, for example, when the additive 21 is mixed with the wire 12 in advance, the temperature rises during heating by the arc, and defects such as evaporation of the additive 21 are likely to occur.

[0028] In contrast, in the present embodiment, the additive 21 is added to the droplet 15 having a relatively small heat capacity. Therefore, the particle phase 35 due to the additive 21 can be rapidly cooled while remaining dispersed in the matrix 34 of the sliding layer 32. Further, in the present embodiment, the occurrence of defects due to evaporation of the additive 21 can be reduced.

[0029] The sliding layer 32 formed on the base material 11 by welding is set to have a thickness T such that 0 mm < T ≤ 0.5 mm by machining such as cutting or polishing. Thus, by forming the sliding layer 32 by welding, the sliding layer 32 does not require tensile strength as compared with the case of using, for example, a bush. Therefore, the thickness T of the sliding layer 32 can be made as thin as 0.5 mm or less. Through the above procedure, a sliding member 30 having the sliding layer 32 laminated on the base material 11 is manufactured.

[0030] The sliding member 30 includes a base material 11 and a sliding layer 32 as shown in FIGS. 3 and 4. In the case of this embodiment, as shown in FIG. 4, particles 35 made of an additive 21 are uniformly and finely dispersed in the matrix 34. Metals with low melting points such as Pb and Bi contained in the low-hardness phase of the particle phase 35 form soft Pb phases and Bi phases compared to the matrix 34 of the sliding layer 32. Therefore, the low-hardness phase of the particle phase 35 enhances the ability to embed foreign matter at the sliding portion during the sliding of the sliding member 30 and the mating material, contributing to an improvement in seizure resistance. On the other hand, the high-hardness phase of the particle phase 35 removes adhered substances generated during the sliding of the sliding member 30 and the mating material. If foreign matter such as adhered substances generated by sliding adheres to the mating material at the sliding portion between the sliding member 30 and the mating material, the adhered substance may come into contact with the sliding surface 33 of the sliding member 30, and seizure may occur at that portion. The high-hardness phase, such as Mo2C, contained in the sliding layer 32 scrapes off the foreign matter adhering to this sliding portion. Thus, the high-hardness phase of the particle phase 35 contributes to reducing seizure between the sliding member 30 and the mating member.

[0031] (An Example of the Sliding Member's Embodiment) An example of the embodiment of the sliding member 30 was verified. In the example of the embodiment, using the welding apparatus 10 shown in FIG. 1, the sliding layer 32 was formed on a steel plate serving as the base material 11 by arc welding using a Cu alloy wire 12. When welding the wire 12 to the base material 11, the powdery additive 21 was supplied to the molten droplets 15 of the wire 12. The wire 12 is an alloy mainly composed of Cu of Cu - Si - Mn, and forms a Cu-based alloy sliding layer 32. The powder of the additive 21 used was Cu - 22Pb - 1.5Sn (mass%). The shielding gas 17 used was Ar containing 2 vol% of O2. The voltage applied between the base material 11 and the wire 12 was set to 14 V, and the welding current was set to 85 A. As a result, as shown in FIG. 4, a structure in which Pb as the particle phase 35 was uniformly and finely dispersed was formed in the sliding layer 32. The Pb phase was very fine, and the diameter in any cross-section was 0.5 to 3 μm.

[0032] As described above, in this embodiment, the additive 21 is added to the droplets 15 formed by melting the wire 12. As a result, the particle phase 35 made of the additive 21 is uniformly and finely dispersed in the matrix 34 of the formed sliding layer 32. Therefore, while enhancing the sliding performance, by selecting the additive 21, the sliding performance can be appropriately controlled according to the application.

[0033] As shown in FIG. 8, the sliding member 30 formed in this embodiment can be suitably used for a large-scale and high-surface-pressure rotating member 40 such as the shaft or bearing of a wind power generator. In the case of the example shown in FIG. 8, the rotating member 40 includes a base material 11 and a sliding layer 32. The rotating member 40 includes a rotating shaft portion 41 and a sliding layer 32. And the sliding layer 32 is directly provided on the rotating shaft portion 41 made of the base material 11 by welding. That is, in the rotating member 40, the sliding layer 32 is laminated on the outer peripheral side of the rotating shaft portion 41 which is a shaft member serving as the base material 11. These rotating shaft portion 41 and sliding layer 32 constitute the sliding member 30. In this way, by directly providing the sliding layer 32 on the rotating shaft portion 41 by welding, the sliding member 30 provided with the sliding layer 32 whose sliding performance is controlled can cope with a high surface pressure.

[0034] Next, the sliding layer 32 will be described in detail. The sliding layer 32 has the matrix 34 and the particle phase 35 as described above. The area ratio Sv of the particle phase 35 is 0.2% ≦ Sv ≦ 5%. Specifically, as shown in FIG. 9, an arbitrary observation cross-section 50 is set for the sliding layer 32. The observation cross-section 50 can be arbitrarily set in the sliding layer 32, for example, in the thickness direction as shown in FIG. 9. The observation cross-section 50 arbitrarily set in the sliding layer 32 includes the matrix 34 and the particle phase 35 as shown in FIG. 10. The observation region 51 is extracted from this observation cross-section 50. A plurality of observation regions 51 are extracted at arbitrary positions in the observation cross-section 50. In this case, the observation region 51 is extracted from the observation cross-section 50 as a region with a size of 500 μm × 500 μm or more. If the observation region 51 is too small, the particle phase 35 may not be included in the observation region 51. That is, the observation region 51 needs to be in a range of a size sufficient for the particle phase 35 to be included. The observation region 51 can be set to any dimension as long as it is in the range of 500 μm × 500 μm or more described above.

[0035] The area ratio Sv of the particle phase 35 in this observation region 51 is 0.2% ≦ Sv ≦ 5%. The area ratio Sv is calculated as Sv = Sm / S × 100 from the area S of the observation region 51 and the total area Sm of the particle phase 35 included in this observation region 51. In the present embodiment, this area ratio Sv is 0.2% ≦ Sv ≦ 5% in any of the plurality of arbitrary observation regions 51 extracted from the observation cross-section 50. That is, the particle phase 35 has an area ratio Sv of 0.2% ≦ Sv ≦ 5% in any of the observation regions 51. This indicates that the particle phase 35 is uniformly dispersed in the matrix 34 of the sliding layer 32. Also, the maximum particle diameter Da of the particle phase 35 is 0 μm < Da ≦ 30 μm. The maximum particle diameter Da may be observed in the observation cross-section 50 or in the observation region 51. In any case, the maximum particle diameter Da of the particle phase 35 included in the sliding layer 32 is 0 μm < Da ≦ 30 μm. Thus, it is shown that the particle phase 35 dispersed in the matrix 34 of the sliding layer 32 is fine with a maximum particle diameter Da of 30 μm or less.

[0036] The volume ratio W of the particle phase 35 contained in the sliding layer 32 is preferably 0.1 vol% ≦ W ≦ 5.0 vol%. The volume ratio W is the sum of the volumes of the particle phases 35 with respect to the volume of the sliding layer 32. It is more preferable that this volume ratio W is 0.2 vol% ≦ W ≦ 2.0 vol%. Among the particle phases 35, especially the high-hardness phase further contributes to the improvement of seizure resistance when the volume ratio W is 0.1 vol% or more. Also, it is preferable that the upper limit of the volume ratio W is 5.0 vol%. By setting the volume ratio W to 5.0 vol% or less, the aggressiveness to the mating material is effectively suppressed.

[0037] The adhesive strength F between the base material 11 and the sliding layer 32 is preferably 250 N / mm 2 ≦ F. In this way, by ensuring the adhesive strength F, even if the rotating shaft portion 41 serving as the base material 11 deflects, peeling of the sliding layer 32 from the base material 11 is surely avoided. Also, when forming the sliding layer 32, the depth Tt at which the base material 11 is affected by heat in the thickness direction is preferably Tt ≦ 500 μm. By appropriately ensuring the temperature of the base material 11 during welding, the range in which the base material 11 is affected by the heat of welding is reduced. Therefore, the influence on the strength of the base material 11 is decreased. That is, in the case of this embodiment, the time during which the base material 11 is heated is extremely short, and the influence of heat on the base material 11 is small. Therefore, it is possible to reduce the change in the structure of the base material 11 due to heat and the accompanying influence on the strength of the base material 11.

[0038] The surface roughness Ra of the sliding layer 32 is preferably Ra ≦ 0.6. In particular, it is more preferable that the surface roughness Ra of the sliding layer 32 is 0.3 ≦ Ra ≦ 0.6. By setting the surface roughness Ra of the sliding layer 32 in this way, while reducing the friction coefficient of the sliding layer 32, it is possible to reduce the processing man-hours and processing accuracy, and to simplify the equipment accompanying the reduction in processing accuracy.

[0039] Hereinafter, specific examples and comparative examples of the sliding member 30 will be described. The examples and comparative examples were evaluated by adhesion tests and sliding tests. The test pieces were formed by surfacing the sliding layer 32 on the Fe-based base material 11 with the wire 12 and the additive material 21 by MIG welding using the CMT method in which the wire 12 was repeatedly supplied to the molten pool generated during welding at high speed in the forward and reverse directions. After welding, the test pieces were machined into a predetermined shape by machining such as cutting and polishing.

[0040] In the adhesion test, the adhesion strength was evaluated as the strength of the sliding member 30. The adhesion strength is the adhesion force between the base material 11 and the sliding layer 32. In the adhesion test, as shown in FIGS. 11 and 12, a test piece 60 in which the base material 11 and the sliding layer 32 were joined with a predetermined joint area was used. The adhesion strength was measured by applying a tensile load to both ends of the test piece 60 and measuring the maximum tensile force at which the joint portion 61 was broken. The test piece 60 used had an overlap of 9 mm × 0.3 mm at the joint portion 61 between the base material 11 and the sliding layer 32, and the joint area was 2.7 mm 2 That is, the test piece 60 had a width of 9 mm and a length of the overlapping portion of 0.3 mm. The adhesion test was carried out by applying a load of 2 kN outward at a speed of 5 m / min to both ends of the test piece 60.

[0041] In the sliding test, the seizure resistance by the seizure test and the wear resistance by the wear test were evaluated as the strength and sliding characteristics of the sliding member 30. In the seizure test, the maximum surface pressure at which the sliding member 30 does not seize was evaluated as the seizure resistance. In the wear test, the wear amount of the sliding member 30 was evaluated as the wear resistance. The seizure test and the wear test in the sliding test were carried out by attaching a test piece 70 formed in an arc shape as shown in FIGS. 13 and 14 to a holder 71 and pressing the test piece 70 attached to the holder 71 against a cylindrical test shaft 72. The sliding test evaluated the examples and comparative examples of the sliding member 30 by the seizure test under the conditions shown in FIG. 15 and the wear test under the conditions shown in FIG. 16.

[0042] The evaluation results of the examples and comparative examples are shown in FIGS. 17 and 18, respectively. The area ratio Sv of the particle phase 35 is calculated by arbitrarily extracting 10 observation regions 51 from an arbitrary observation cross section 50 and calculating the maximum and minimum values of the area ratio Sv in each of the extracted observation regions 51. That is, in the cases of FIGS. 17 and 18, the area ratio Sv is the maximum and minimum values of the 10 observation regions 51. The maximum particle diameter Da of the particle phase 35 is the particle diameter of the largest particle phase 35 among the particle phases 35 in the 10 observation regions 51 extracted from the observation cross section 50. The observation region 51 was set to 500 μm × 500 μm. In the seizure test, a maximum surface pressure of 18 MPa or more without seizure was defined as "qualified". In the wear test, a wear amount of 5 μm or less was defined as "qualified". Note that in the seizure test, 25 MPa is the maximum value due to the performance limitations of the test equipment.

[0043] As shown in FIG. 17, Samples 1 to 9, which are examples, all have qualified adhesive strength, maximum surface pressure, and wear amount. On the other hand, as shown in FIG. 18, Samples 10, 13, and 16, which are comparative examples, have an excessive area ratio Sv of the particle phase 35. Therefore, although the wear amount of these Samples 10, 13, and 16 decreases, it can be seen that they have high aggressiveness to the mating material and cause a decrease in seizure resistance. Also, Samples 11, 14, and 17, which are comparative examples, have the particle phase 35 aggregated and the maximum particle diameter Da is excessive. When the particle phase 35 aggregates, the seizure resistance and wear resistance of the sliding layer 32 vary depending on the location. Therefore, it can be seen that in these Samples 11, 14, and 17, the distribution of the particle phase 35 in the matrix 34 becomes non-uniform, and the seizure resistance and wear resistance deteriorate.

[0044] Samples 12, 15, and 18, which are comparative examples, have an excessively small area ratio Sv of the particle phase 35 contained in the sliding layer 32. Therefore, it can be seen that for these samples 12, 15, and 18, improvement in seizure resistance and wear resistance cannot be expected. Samples 19 and 20, which are comparative examples, add the additive 21 to the molten pool formed in the base material 11. Therefore, samples 19 and 20 are causing segregation in which the particle phase 35 is locally generated. It can be seen that for samples 19 and 20, the variations in seizure resistance and wear resistance are increasing due to this segregation. Samples 21 and 22, which are comparative examples, do not add the additive 21 and the particle phase 35 is not contained in the sliding layer 32. Therefore, it can be seen that for samples 21 and 22, the seizure resistance and wear resistance deteriorate.

[0045] The present invention described above is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist thereof. For example, in addition to the base material 11 and the sliding layer 32, the sliding member 30 may include an overlay layer (not shown). In this case, the overlay layer is formed by overlapping the sliding layer 32 on the surface of the sliding layer 32, that is, the surface opposite to the base material 11. It is preferable to use a soft metal or alloy such as Sn or Bi for the overlay layer. Also, for the overlay layer, for example, a resin in which a solid lubricant is dispersed may be used. When the sliding member 30 includes an overlay layer, the outermost surface of this overlay layer becomes the sliding surface 33 that slides against the mating material. Further, the sliding member 30 may include one or more intermediate layers (not shown) between the base material 11 and the sliding layer 32. In this case, it is preferable to use a material such as Ni or its alloy that enhances the adhesive force between the base material 11 and the sliding layer 32 for the intermediate phase.

Claims

1. A base material, A sliding layer laminated on the base material, having a matrix and a particle phase uniformly and finely dispersed in the matrix, A sliding member comprising: In the matrix, either Cu or Sn is the first component, The particle phase includes a high-hardness phase having a higher hardness than the matrix, When an arbitrary observation cross-section is set in the sliding layer and a plurality of observation regions having a size of 500 μm × 500 μm or more are extracted from the observation cross-section, the area ratio Sv of the particle phase in the plurality of observation regions is 0.2% ≤ Sv ≤ 5% in any of the observation regions, The maximum particle diameter Da of the particle phase is 0 μm < Da ≤ 30 μm, Sliding member.

2. When the Vickers hardness of the particle phase is HV1 and the Vickers hardness of the matrix is HV2, 5 ≤ HV1 / HV2 ≤ 50, The sliding member according to Claim 1.

3. The high-hardness phase is At least one element selected from Ni, Sn, Mo, C, B, Si, Mn, Fe, P, Ti, Al, W, Cr, Sc, Zr, Co, Cu or a compound thereof, or a compound with O or N, The sliding member according to Claim 1.

4. The volume ratio W of the high-hardness phase contained in the sliding layer is 0.1 vol% ≤ W ≤ 5.0 vol%, The sliding member according to Claim 1.

5. The particle phase includes a low-hardness phase having a lower hardness than the matrix, The sliding member according to Claim 1.

6. The adhesive strength F between the base material and the sliding layer is 250 N / mm² ≤ F, The sliding member according to Claim 1.

7. The thickness T of the sliding layer is 0 mm < T ≤ 0.5 mm, The sliding member according to Claim 1.

8. The thickness Tt of the base material affected by heat from the sliding layer in the thickness direction is Tt ≤ 500 μm, The sliding member according to Claim 1.

9. The surface roughness Ra of the sliding layer is Ra ≤ 0.6, The sliding member according to Claim 1.

10. The roughness Ra is 0.3 ≤ Ra ≤ 0.6, The sliding member according to Claim 9.

11. A gearbox comprising the sliding member according to any one of Claims 1 to 10, The base material is a shaft member, and the sliding layer is laminated on the outer peripheral side of the shaft member, Gearbox.

12. Comprising the gearbox according to Claim 11, Wind turbine. A method for manufacturing a sliding member that forms a sliding layer by intermittently arc-welding a wire to a base material while repeatedly supplying the wire to the base material side and moving it back to the opposite side at a preset cycle and amount of movement, comprising: a step of supplying the wire that becomes the matrix constituting the sliding layer; a step of melting the supplied wire by discharging it with the base material to form a molten droplet of the wire when the wire approaches the base material; a step in which when the formed molten droplet contacts the base material and the wire and the base material are electrically short-circuited, the discharge between the wire and the base material stops and the molten droplet migrates to the base material; a step in which the wire and the base material are separated as the wire moves away from the base material, and including: a step of adding an additive to be added to the matrix to the molten droplet formed by the discharge between the wire and the base material; A method for manufacturing a sliding member including the above.

14. The method for manufacturing a sliding member according to claim 13, wherein the additive added to the matrix is added to the molten droplet as particles, powder containing the particles, wire containing the particles, or bar containing the particles.

15. After the sliding layer is formed, a step of making the thickness of the sliding layer 0.5 mm or less by machining, The method for manufacturing a sliding member according to claim 13, further including the above.

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