Metal bearing and method for manufacturing the same

Abstract

To provide a metal bearing that can easily improve sliding performance while maintaining corrosion resistance. [Solution] This metal bearing 10 is formed by compressing a knitted fabric consisting of a first stainless steel metal wire 20 and a second metal wire 30 made of a different material from the first metal wire 20 in a direction at least perpendicular to the axial direction of the metal bearing 10. Furthermore, the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing 10, is set to 2.2 to 39.8%. In addition, the ratio of the volume of the second metal wire 30 to the volume of the first metal wire 20 and the second metal wire 30 is set to 20 to 67%.

Description

Technical Field

[0001] The present invention relates to a cylindrical metal bearing and a method for manufacturing the same.

Background Art

[0002] For example, various shapes and structures of bushes disposed on the outer periphery of a rotating shaft and the like have been adopted. One of them is a so-called wire bush made of a woven metal wire material.

[0003] Patent Document 1 listed below describes a control valve device used in an Exhaust Gas Recirculation (EGR) system, and discloses a wire bush that serves as a bearing for slidably supporting a valve shaft constituting the control valve device. This wire bush is formed by braiding a single thin stainless steel metal wire and winding it into a roll to form a cylindrical shape.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the bearing described in Patent Document 1 has a configuration in which a single thin stainless steel metal wire is braided, although it has good corrosion resistance due to the properties of stainless steel itself, it is prone to wear and has a problem in sliding performance for allowing the shaft to slide.

[0006] Accordingly, an object of the present invention is to provide a metal bearing and a method for manufacturing the same, which can easily enhance sliding performance while maintaining corrosion resistance.

Means for Solving the Problems

[0007] To achieve the above objective, one aspect of the present invention is a cylindrical metal bearing characterized in that a knitted fabric consisting of a first metal wire made of stainless steel and a second metal wire made of a different material from the first metal wire is compressed at least in the axial direction of the metal bearing.

[0008] According to the above invention, since the first metal wire constituting the compressed knitted fabric is made of stainless steel, the corrosion resistance of the entire metal bearing can be maintained.

[0009] Furthermore, since the compressed knitted fabric consists not only of a first metal wire but also of a second metal wire made of a different material, it can suppress the adhesion and wear that can occur between metal wires when multiple metal wires are made of the same material. Therefore, compared to the case where the entire knitted fabric is made of metal wires of the same material, it is possible to obtain a good balance of desired sliding performance for the sliding surface of the metal bearing under both room temperature and high temperature conditions.

[0010] As described above, this invention provides a metal bearing that can easily improve sliding performance while maintaining corrosion resistance.

[0011] In the metal bearing according to the present invention, the second metal wire may be softer than the first metal wire. According to this embodiment, the sliding performance at the sliding surface of the metal bearing can be more easily improved.

[0012] In the metal bearing according to the present invention, the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing, may be set to 2.2 to 39.8%. According to this embodiment, it is possible to provide a metal bearing that can obtain a better balance of desired sliding performance in both a room temperature atmosphere and a high temperature atmosphere for the sliding surface of the metal bearing.

[0013] In the metal bearing according to the present invention, the ratio of the volume of the second metal wire to the volume of the first metal wire and the second metal wire may be 20 to 67%. According to this embodiment, the sliding performance of the sliding surface of the metal bearing can be further improved in both room temperature and high temperature atmospheres.

[0014] In the metal bearing according to the present invention, the second metal wire 30 may be made of at least one metal selected from pure Ni, Ni-based metals, pure Cu, and Cu-based metals. According to this embodiment, the sliding performance of the sliding surface of the metal bearing can be further improved, especially in a room temperature atmosphere.

[0015] Another aspect of the present invention is a method for manufacturing a cylindrical metal bearing, A sheet forming process for forming a knitted sheet consisting of a first metal wire made of stainless steel and a second metal wire made of a different material from the first metal wire, A sheet winding step in which the aforementioned sheet is wound into a cylindrical shape, The present invention is characterized by comprising a sheet compression step, in which the sheet wound in a cylindrical shape is compressed at least in the axial direction of the metal bearing such that the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing, is 2.2 to 39.8%.

[0016] According to the above invention, it is possible to manufacture a metal bearing that can easily improve sliding performance while maintaining corrosion resistance.

[0017] Furthermore, in the method for manufacturing a metal bearing according to the present invention, A sintering step of sintering the compressed metal bearing, The process may include a dimension adjustment step in which, while the outer circumferential surface of the sintered metal bearing is restrained, an adjustment member of a desired outer diameter is brought into contact with the inner circumferential surface of the metal bearing to adjust the inner diameter dimension of the metal bearing, or while the inner circumferential surface of the sintered metal bearing is restrained, an adjustment member of a desired inner diameter is brought into contact with the outer circumferential surface of the metal bearing to adjust the outer diameter dimension of the metal bearing.

[0018] According to the above aspect, it is possible to manufacture a metal bearing that has high rigidity and strength, can achieve improved sag resistance, and has excellent dimensional accuracy. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a metal bearing that can easily enhance sliding performance while maintaining corrosion resistance. [Brief Description of the Drawings]

[0020] [Figure 1] This drawing shows an embodiment of the metal bearing according to the present invention, and is a photograph of its perspective state. [Figure 2] This is a photograph of the same metal bearing as viewed from the axial direction. [Figure 3] This is a schematic cross-sectional view of the same metal bearing. [Figure 4] This is an explanatory view showing the state of a plurality of metal wires in a state before the knitted fabric constituting the same metal bearing is compressed. [Figure 5] This is an explanatory view for determining the flatness ratio at the axial end face of the same metal bearing. [Figure 6] This is a graph for determining the flatness ratio of the same metal bearing, and is a digital measurement curve obtained based on the reference line in a coordinate system consisting of a vertical axis and a horizontal axis, where the trajectory of the stylus of the measuring instrument moving along the reference guide is taken as the reference line. [Figure 7] This is an explanatory view for determining the flatness ratio on the sliding surface of the same metal bearing. [Figure 8] This is an explanatory view of a wear test for determining the wear amount of the same metal bearing. [Figure 9] This is a flow chart of the method for manufacturing a metal bearing according to the present invention. [Figure 10] This is an explanatory view of the sheet forming step of the same manufacturing method. [Figure 11] This is an explanatory view of the sheet winding step of the same manufacturing method. [Figure 12] This is an explanatory view of the sheet compressing step of the same manufacturing method. [Figure 13]This is an explanatory diagram of the dimensional adjustment process for the same manufacturing method. [Figure 14] This graph shows the results of a wear test of the metal bearing according to the present invention under a 25°C atmosphere, with the horizontal axis representing the ratio of the volume of the second metal wire to the total volume of the first metal wire (Ni content (%)) and the vertical axis representing the total wear amount. [Figure 15] This graph shows the results of a wear test of the metal bearing according to the present invention under a 500°C atmosphere, with the horizontal axis representing the ratio of the volume of the second metal wire to the total volume of the first and second metal wires, and the vertical axis representing the total wear amount. [Modes for carrying out the invention]

[0021] (An embodiment of a metal bearing) Hereinafter, an embodiment of the metal bearing according to the present invention will be described with reference to the drawings.

[0022] As shown in Figures 1-4, the metal bearing 10 is cylindrical in shape and is constructed by compressing a knitted fabric consisting of a first stainless steel metal wire 20 and a second metal wire 30 made of a different material from the first metal wire 20, at least in the axial direction of the metal bearing 10. In this embodiment, the knitted fabric constituting the metal bearing 10 is compressed not only in its axial direction but also in a direction perpendicular to the axial direction. That is, the knitted fabric is compressed in the axial direction and in a direction perpendicular to the axial direction.

[0023] Furthermore, the metal bearing 10 in this embodiment is substantially cylindrical. As shown in Figure 3, the line segment passing through the radial center of the metal bearing 10 and along the axis is defined as the axis C of the metal bearing 10. In the following description, "axial direction" and "axial direction" refer to the direction along the axis C of the metal bearing 10, and "radial direction" refers to the direction perpendicular to the axial direction.

[0024] Furthermore, the metal bearing 10 has an axial end face 15. Note that the radial inner circumferential surface 11, the radial outer circumferential surface 13, or the axial end face 15 of the metal bearing 10 are designated as the "sliding surface" in this invention.

[0025] Furthermore, this metal bearing 10 can also be described as a so-called "wire bushing" in which multiple metal wires are braided together and the inner or outer circumferential surface forms a sliding surface. However, the metal bearing may also be a member that receives the load at its axial end face.

[0026] Furthermore, although the metal wires 20 and 30 in this embodiment are round wires with a circular cross-section, the metal wires may also be square wires or the like with a rectangular cross-section.

[0027] As mentioned above, the first metal wire 20 is made of stainless steel. As for the stainless steel, for example, austenitic stainless steel such as SUS316L, SUS316, SUS301, SUS303, SUS304, SUS310S, SUS304L, and SUS317 according to JIS standards, or ferritic stainless steel such as SUS430, or even martensitic stainless steel such as SUS403, SUS410, and SUS630 can be used.

[0028] In particular, it is preferable to use SUS316L stainless steel, which has superior corrosion resistance compared to SUS304 and is also highly resistant to intergranular stress corrosion cracking.

[0029] Furthermore, the wire diameter of the first metal wire 20 (or the maximum outer dimension if the cross-section is not circular) is preferably 0.05 to 0.5 mm, more preferably 0.10 to 0.28 mm, and most preferably 0.15 mm.

[0030] Furthermore, the diameter of the first metal wire 20 may be larger or smaller than the diameter of the second metal wire 30, and the diameters of the first metal wire 20 and the second metal wire 30 may be the same.

[0031] Furthermore, the second metal wire 30, which is different from the first metal wire 20, may be softer than the first metal wire 20. In addition, the second metal wire 30 may be made of at least one metal selected from pure Ni, Ni-based metals, pure Cu, and Cu-based metals.

[0032] When a nickel-based metal is used as the material for the second metal wire 30, examples of nickel-based metals that can be used include Ni-Cr (NCH1, NCH2, etc.), Ni-Cu (Monel 400, etc.), Ni-Cr-Fe (Inconel X750, etc.), and Ni-Cr-Mo (Hastelloy C-276, etc.).

[0033] Furthermore, when a Cu-based metal is used as the material for the second metal wire 30, examples of Cu-based alloys that can be used include Cu-Zn, Cu-NI, Cu-Mn-Ni, Cu-Mn-Sn, Cu-Cr, Cu-Zr-Cr, Cu-Mg-Zn, Cu-Fe, etc.

[0034] Furthermore, the wire diameter of the second metal wire 30 (or the maximum outer dimension if the cross-section is not circular) is preferably 0.05 to 0.5 mm, more preferably 0.10 to 0.28 mm, and most preferably 0.15 mm.

[0035] The number of first metal wires 20 may be one or more, and the number of second metal wires 30 may also be one or more. Furthermore, the number of first metal wires 20 may be greater than the number of second metal wires 30, the number of second metal wires 30 may be greater than the number of first metal wires 20, and the number of first metal wires 20 and second metal wires 30 may be the same.

[0036] Figure 4 shows the state of multiple metal wires before the knitted fabric constituting the metal bearing 10 is compressed. As shown in Figure 4, in this embodiment, there are two first metal wires 20 and one second metal wire 30, and furthermore, all of these metal wires 20, 20 and 30 have the same wire diameter.

[0037] These multiple metal wires 20, 20, 30 are then aligned and placed in parallel between adjacent wires, and these parallel-arranged metal wires 20, 20, 30 are knitted and / or braided to form a knitted fabric. In this embodiment, the knitted fabric is made using so-called stockinette stitch, but the knitting method is not particularly limited and may include plain weave, for example.

[0038] In this embodiment, when multiple metal wires are arranged, as shown in Figure 4, identical metal wires are placed adjacent to each other (the first metal wires 20, 20 are placed adjacent to each other). However, for example, metal wires of different materials may be placed between metal wires of the same material, or metal wires of different materials may be placed alternately.

[0039] Furthermore, Figure 1 shows a perspective view of the metal bearing 10, and Figure 2 shows a view of the metal bearing 10 from the axial direction. As shown in Figures 1 and 2, the metal bearing 10, which is formed by compressing a knitted fabric made of multiple first and second metal wires in the axial direction, has a structure in which the multiple first and second metal wires are intertwined with each other, sometimes in contact with each other and sometimes with gaps between them, even in the compressed state of the knitted fabric, and has countless voids inside.

[0040] As described above, the shape in which multiple first and second metal wires intertwine with each other in a compressed state of the knitted fabric, resulting in countless internal voids, appears on the radial outer surface 13 of the metal bearing 10 (see Figure 1), similarly on the radial inner surface 11 that forms the sliding surface, and also similarly on the axial end surface 15 (see Figures 1 and 2).

[0041] By the way, as described above, the metal bearing 10 of this embodiment is constructed by compressing a substantially cylindrical knitted fabric in the axial direction, but the cylindrical metal bearing may also be a sintered body formed by sintering a compressed knitted fabric.

[0042] Furthermore, in the metal bearing 10, the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface, is preferably 2.2 to 39.8%, and preferably 7.9 to 29.0%.

[0043] The total length of the sliding surface refers to the length from one end face to the other in the axial direction of the metal bearing when the inner or outer circumferential surface of the metal bearing is used as the sliding surface. When the axial end face of the metal bearing is used as the sliding surface, it refers to the length from the inner circumferential surface (inner diameter surface edge) to the outer circumferential surface (outer diameter surface edge) of the metal bearing, extending radially outward (radial direction) from the axis of the metal bearing (thickness in the direction perpendicular to the axial direction).

[0044] Within the range of 2.2-39.8% mentioned above, the amount of wear on the sliding surface tends to decrease, and in particular, the greater the flatness ratio, the less wear there tends to be on the sliding surface. This is thought to be because a larger flatness ratio on the sliding surface increases the pressure-receiving area, thus reducing the surface pressure.

[0045] The flatness ratio described above will be explained with reference to Tables 1 and 2 below. In Tables 1 and 2, "No." refers to the sample number of the embodiment and the sample number of the comparative example of the present invention. In Tables 1 and 2, "1," "2," and "6" to "18" are embodiments, and "3" to "5" are comparative examples. The wire diameters of the first and second metal wires in Tables 1 and 2 are the same. The conditions for the embodiment and comparative example will be described in detail in the "Embodiment" section below.

[0046] [Table 1]

[0047] [Table 2]

[0048] When determining the flatness ratio as described above, a graph is created in accordance with Japanese Industrial Standard JIS B0651 3.1.2 "Reference profile: The trajectory of a stylus as it moves along a reference guide," and / or 3.1.3 "Total profile: A digital measurement curve obtained based on the reference line in a coordinate system consisting of a vertical axis and a horizontal axis." In this embodiment, a well-known contact-type shape measuring machine 40 having a stylus 41 as shown in Figure 5 is used to measure the length from the inner circumferential surface 11 to the outer circumferential surface 13 of the metal bearing 10, extending radially outward from the axis (see axis C) of the metal bearing 10, at the axial end face 15 that can become the sliding surface of the metal bearing 10. The graph is created in a digital measurement curve obtained based on the reference line in a coordinate system consisting of a vertical axis and a horizontal axis.

[0049] In other words, a graph is created in which the horizontal axis represents the motion trajectory (movement trajectory) of the stylus 41 of the shape measuring machine 40 when it moves along a reference guide, and the vertical axis represents the amplitude of the stylus 41.

[0050] Furthermore, when determining the flatness ratio from the inner circumferential surface 11 of the metal bearing 10, as shown in Figure 7, the length from one end face 15 to the other end face 15 in the axial direction of the metal bearing 10 is measured on the inner circumferential surface 11 of the metal bearing 10, and a digital measurement curve graph is created.

[0051] Then, in the graph above, the areas where the amplitude of the stylus 41 is approximately constant and the horizontal length on the graph is greater than or equal to a predetermined value (in this case, 0.01 mm) are extracted as "flat sections H," and the total length of the extracted flat sections H is calculated. The ratio of the total length of the flat sections H to the total length of the sliding surface is defined as the flatness ratio. The graph shown in Figure 6 is a partial enlargement of the measurement results of the flatness ratio as described above.

[0052] Furthermore, in this embodiment, the shape measuring machine 40 is a product named "SURFCOM 1800G" manufactured by Tokyo Seimitsu Co., Ltd., and its measuring terminal (manufactured by Tokyo Seimitsu Co., Ltd., product name "DM45511") has a tip radius of 0.025 mm, a measuring speed of 0.150 mm / s, and a measuring pitch of 1.00 μm.

[0053] When measuring the flatness from the inner circumferential surface 11 or outer circumferential surface 13 of the metal bearing 10, the shape measuring machine 40 measures at four locations at 90° intervals in the radial direction of the metal bearing 10, and the average of these measurements is taken as the flatness. Similarly, when measuring the flatness from the axial end face 15 of the metal bearing 10, the shape measuring machine 40 measures at four locations at 90° intervals in the circumferential direction of the metal bearing 10, and the average of these measurements is taken as the flatness.

[0054] Furthermore, the statement above that "the amplitude of the stylus 41 is approximately constant" means that the slope in the graph above is either 0° (no slope) or in the range of -5° to +5° relative to 0°.

[0055] Furthermore, if the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface, is less than 2.2%, the amount of wear at room temperature and high temperature tends to increase. If the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface, exceeds 39.8%, problems may arise in the sheet compression process S3 (see Figure 12) described later, such as difficulty in setting the sheet 70 wound inside the cavity of the mold 71, or difficulty in removing the shaft portion 72a of the core member 72 from the inner circumferential surface 11 of the metal bearing 10.

[0056] In other words, in order to increase the flatness ratio, it is necessary to form the sliding surface of the metal bearing with high surface pressure. However, when attempting to form the sliding surface with high surface pressure, it is thought that problems may arise such as difficulty in setting the sheet wound in the sheet compression process shown in Figure 12 into the cavity of the mold 71, or difficulty in removing the core member 72 from the inner circumferential surface 11 of the metal bearing 10.

[0057] Furthermore, in Tables 1 and 2, "metal bearing specific wear" is an index related to the wear of the metal bearing, "mating material specific wear" is an index related to the wear of the mating component, and "total wear" means the sum of "metal bearing specific wear" and "mating material specific wear." These are calculated as follows.

[0058] Specifically, as shown in Figure 8, a metal bearing is placed in a concave arrangement portion 51 provided at the axial upper end of a columnar housing 50. Then, a rotating shaft 60 that reciprocates in the range of 0° to 90° (repeated forward rotation from 0° to 90° and return rotation from 90° to 0°) continuously presses one axial end face of the metal bearing (in this case, the upper end face in Figure 8) for a predetermined time.

[0059] In this case, the difference between the state of one axial end face of the metal bearing before being pressed by the rotating shaft (left side in Figure 8) and the state after being pressed by the rotating shaft 60 (right side in Figure 8) is defined as the bearing wear. Similarly, the difference between the state of one axial end face of the shaft of the mating material (rotating shaft 60) before being pressed by the metal bearing (left side in Figure 8) and the state after being pressed by the metal bearing (right side in Figure 8) is defined as the mating material wear.

[0060] Furthermore, the specific wear amount shown in formula (1) below is determined from each condition. Note that the specific wear amount is determined for both the metal bearing itself and the wear amount of the mating component (rotating shaft 60).

[0061]

number

[0062] In the above formula (1), "K" is the specific wear rate (mm / (N / mm 2 The formula is (×m / s×hr), where "W" is the wear amount (mm) and "P" is the surface pressure (N / mm) applied by the rotating shaft to one axial end face of the metal bearing. 2 ) where "V" is the reciprocating rotational speed of the rotating shaft (m / s) and "T" is the total time of the rotational motion of the rotating shaft (h).

[0063] Furthermore, in the metal bearing 10, the ratio of the volume of the second metal wire 30 to the total volume of the first metal wire 20 and the second metal wire 30 is preferably 20-67%, and more preferably 20-45%.

[0064] This will be explained with reference to Table 3 below. In Table 3, "No." refers to the sample number of the examples and comparative examples of the present invention, and is the same as in Tables 1 and 2. In Table 1, "4," "3," and "5" are comparative examples, and "14," "1," "15," "6," and "2" are examples. The conditions of the examples and comparative examples will be described in detail in the "Examples" section below.

[0065] [Table 3]

[0066] Note that "total wear" in Table 3 refers to the sum of the wear of the metal bearing itself (relative wear of the bushing) and the wear of the mating component (relative wear of the mating component).

[0067] Furthermore, in Table 3, the wire diameters of the first metal wire 20 and the second metal wire 30 are the same. Therefore, the ratio of the number of second metal wires 30 to the total number of first metal wires 20 and second metal wires 30, and the ratio of the volume of second metal wire 30 to the total volume of first metal wires 20 and second metal wires 30 are the same, and the ratio of these volumes is between 20% and 67%.

[0068] Furthermore, if the ratio of the volume of the second metal wire 30 to the volume of the first metal wire 20 and the second metal wire 30 is less than 20%, the amount of wear at room temperature tends to increase, and if the ratio of the volume of the second metal wire 30 to the volume of the first metal wire 20 and the second metal wire 30 exceeds 67%, the amount of wear at high temperatures tends to increase.

[0069] (One embodiment of a method for manufacturing metal bearings) Next, one embodiment of the manufacturing method for metal bearings according to the present invention will be described.

[0070] Referring also to Figure 9, the manufacturing method for the metal bearing in this embodiment (hereinafter also simply referred to as the "manufacturing method") includes a sheet forming step S1, a sheet winding step S2, and a sheet compression step S3. Furthermore, the manufacturing method may also include a sintering step S4 and a dimensional adjustment step S5. Each step will be described in detail below.

[0071] (Sheet formation process S1) As shown in Figure 10, this sheet forming process S1 is a process of forming a sheet 70 that extends to a predetermined length, which is a knitted fabric consisting of a first metal wire 20 made of stainless steel and a second metal wire 30 made of a different material from the first metal wire 20.

[0072] Specifically, multiple metal wires 20, 20, 30 are aligned and placed in parallel, and the parallel-arranged metal wires 20, 20, 30 are knitted and / or braided together (braided) using methods such as jersey knitting or plain weave (the knitting method is not limited) to form a bag-shaped knitted fabric (see left side in Figure 10). This is then passed between a pair of rollers (not shown) and compressed to form a flat sheet 70 as shown on the right side of Figure 10.

[0073] Furthermore, when forming a sheet from plain-woven knitted fabric, for example, the plain-woven knitted fabric can be used directly as a flat sheet, or the plain-woven knitted fabric can be folded multiple times (by two, three, or more times) via rollers, and then the laminated material can be passed between a pair of rollers (not shown) to form a flat sheet.

[0074] (Sheet winding process S2) This sheet winding process S2 is a process in which the sheet 70 formed in the sheet forming process S1 is wound into a cylindrical shape, as shown in Figure 11. When winding the sheet 70, it is wound so that the gaps between adjacent sheets 70 in the radial direction are minimized.

[0075] (Sheet compression process S3) This sheet compression step S3 is a step in which the sheet 70, which was wound into a cylindrical shape in the sheet winding step S2, is compressed at least in the axial direction of the metal bearing 10 so that the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing, is 2.2 to 39.8%.

[0076] Specifically, as shown in Figure 12, first, the wound sheet 70 is placed inside the mold 71. This mold 71 has a core member 72 having a bottom and a columnar shaft portion 72a, and has a structure in which a cavity for forming a metal bearing is provided inside. After the wound sheet 70 is placed inside the mold 71, a cylindrical pressing portion 73 presses one axial end face (in this case, the upper end face) of the wound sheet 70 with a predetermined pressure.

[0077] The metal bearing 10 is manufactured through this sheet compression process S3. If the sintering process S4 and the sliding surface dimension adjustment process S5 described below are not performed, the manufacturing process is terminated.

[0078] Furthermore, in the sheet compression process S3 described above, one end face 15 of the metal bearing 10 in the axial direction is pressed, resulting in expansion in the direction perpendicular to the axial direction (radial direction), and thus it can be said that it is compressed in the direction perpendicular to the axial direction. In other words, it can be said that the knitted fabric constituting the metal bearing 10 is compressed in the axial direction of the metal bearing and in the direction perpendicular to the axial direction.

[0079] (Sintering process S4) This sintering process S4 is a process of sintering the metal bearing 10 that was compressed in the sheet compression process S3. That is, the metal bearing 10 is placed in a heating furnace (not shown) and sintered in a predetermined atmosphere (such as an inert atmosphere) and under normal or pressurized pressure. As a result of this sintering, the multiple metal wires of the knitted fabric that make up the metal bearing 10 are fixed together, so to speak, in a state of being baked and solidified.

[0080] The sintering temperature is preferably 1000 to 1300°C, and more preferably 1100 to 1200°C. The sintering time is preferably 5 to 120 minutes, and more preferably 30 to 90 minutes.

[0081] Furthermore, the above sintering is preferably carried out under an inert atmosphere consisting of, for example, an inert gas with a ratio of H2:N2=75:25. In addition to the above-mentioned inert gas, other inert atmospheres may be used, such as H2:N2=50:50, H2:N2=25:75, H2=100%, N2=100%, Ar gas, or a vacuum.

[0082] (Dimensional adjustment process S5) This sliding surface dimension adjustment step S5 is a process in which, while the outer circumferential surface 13 of the sintered metal bearing 10 is restrained, an adjustment member 79 (see Figure 13) with a desired outer diameter is brought into contact with the inner circumferential surface 11 of the metal bearing 10 to adjust the inner diameter dimension of the metal bearing 10.

[0083] In this embodiment, as shown in Figure 13, the sintered metal bearing 10 is placed inside a restraining mold 77 having an inner circumferential surface and a bottom, thereby restraining the outer circumferential surface 13 of the metal bearing 10. Then, an adjustment member 79 formed with a desired outer diameter is inserted into the inner circumferential surface 11, which forms the sliding surface of the metal bearing 10. As a result, the inner diameter dimension of the inner circumferential surface 11, which is the sliding surface of the sintered metal bearing 10, is adjusted.

[0084] Furthermore, if the sliding surface of the metal bearing is the outer circumferential surface, the inner circumferential surface of the sintered metal bearing is restrained, and an adjustment member with a desired inner diameter is brought into contact with the outer circumferential surface of the metal bearing to adjust the outer diameter dimension of the outer circumferential surface that forms the sliding surface of the sintered metal bearing.

[0085] (Effects and Benefits) Next, the effects and advantages of the metal bearing 10 with the above configuration and the method for manufacturing the metal bearing will be explained.

[0086] In other words, the metal bearing 10 is formed by compressing a knitted fabric consisting of a first stainless steel metal wire 20 and a second metal wire 30 made of a different material from the first metal wire 20 in the axial direction of the metal bearing 10.

[0087] According to the above invention, since the first metal wire 20 constituting the compressed knitted fabric is made of stainless steel, the corrosion resistance of the entire metal bearing can be maintained.

[0088] Furthermore, since the compressed knitted fabric consists not only of the first metal wire 20 but also of the second metal wire 30 made of a different material, it is possible to suppress the adhesion and wear that can occur between metal wires when multiple metal wires are made of the same material. Therefore, compared to the case where the entire knitted fabric is made of metal wires of the same material, it is possible to obtain a good balance of the desired sliding performance of the sliding surface of the metal bearing 10 in both a room temperature atmosphere and a high temperature atmosphere.

[0089] As described above, this invention provides a metal bearing 10 that can easily improve sliding performance while maintaining corrosion resistance.

[0090] Furthermore, the metal bearing 10, formed by compressing a knitted fabric made of multiple first and second metal wires in the axial direction, has a structure in which the multiple first and second metal wires intertwine with each other, sometimes in contact with each other and sometimes with gaps between them, so that even when the knitted fabric is compressed, it has countless voids inside.

[0091] Therefore, for example, when inserting or slidingly positioning a mating member such as a shaft member inside or outside a metal bearing 10, even if the dimensional error of the outer or inner diameter of the shaft member is relatively large, or if the shaft member is deflected, the gap between the wires can absorb such dimensional errors or deflection to some extent, thereby improving the workability of positioning the metal bearing relative to the shaft member.

[0092] Furthermore, in bearings, the support of the shaft member by the sliding surface can become localized (the sliding surface makes uneven contact) due to the tilt or runout of the shaft member. However, in this metal bearing 10, as described above, the structure has countless voids inside, including the sliding surface. Therefore, the sliding surface deforms slightly in response to the tilt of the shaft member, and the sliding surface supports the shaft member by making surface contact over a relatively wide area (the sliding surface can support the shaft member with its surface), allowing the shaft member to be supported in a stable position.

[0093] Furthermore, if the second metal wire 30 is softer than the first metal wire 20, the sliding performance on the sliding surface of the metal bearing 10 can be more easily improved.

[0094] Furthermore, if the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing 10, is set to 2.2 to 39.8%, it is possible to provide a metal bearing 10 that can achieve a better balance of desired sliding performance in both a normal temperature atmosphere and a high temperature atmosphere.

[0095] Furthermore, if the second metal wire 30 is made of at least one metal selected from pure Ni, Ni-based metals, pure Cu, and Cu-based metals, the sliding performance of the sliding surface of the metal bearing 10 can be further improved, especially in a room temperature atmosphere.

[0096] Furthermore, if the first metal wire 20 consists of two wires, and the second metal wire 30 consists of one pure Ni or Ni-based metal wire, then a metal bearing 10 with sufficient corrosion resistance and sliding performance can be provided while keeping manufacturing costs down.

[0097] Furthermore, if the metal bearing 10 is a sintered body formed by sintering a compressed knitted fabric, the rigidity and strength of the metal bearing 10 can be increased compared to an unsintered body, and its resistance to deformation can also be improved.

[0098] Furthermore, the present invention provides a method for manufacturing a metal bearing, comprising: a sheet forming step S1 for forming a knitted sheet 70 consisting of a first metal wire 20 made of stainless steel and a second metal wire 30 made of a different material from the first metal wire 20; a sheet winding step S2 for winding the sheet 70 into a cylindrical shape; and a sheet compression step S3 for compressing the cylindrically wound sheet 70 so that the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing, is 2.2 to 39.8% in at least the axial direction of the metal bearing 10.

[0099] According to the above invention, it is possible to manufacture a metal bearing 10 that can easily improve sliding performance while maintaining corrosion resistance.

[0100] Furthermore, the manufacturing method for a metal bearing may include a sintering step of sintering a compressed metal bearing 10, and a dimensional adjustment step of adjusting the inner diameter of the metal bearing 10 by bringing an adjustment member 79 of a desired outer diameter into contact with the inner circumferential surface 11 of the metal bearing 10 while the outer circumferential surface 13 of the sintered metal bearing 10 is restrained (see Figure 13), or adjusting the outer diameter of the metal bearing 10 by bringing an adjustment member of a desired inner diameter into contact with the outer circumferential surface 13 of the metal bearing 10 while the inner circumferential surface 11 of the sintered metal bearing 10 is restrained.

[0101] According to the above embodiment, it is possible to manufacture a metal bearing 10 that has high rigidity and strength, improved resistance to deformation, and good dimensional accuracy. [Examples]

[0102] (Preparation of examples and comparative examples) Examples and comparative examples were prepared according to the contents shown in Tables 1 and 2 above. The wire diameter of each wire in the examples and comparative examples is 0.15 mm. In Tables 1 and 2, the column for the second metal wire in the examples is marked with dot hatching. Also, when "Sintering" is marked as "Yes" in Tables 1 and 2, the sintering temperature is 1150°C and the sintering time is 90 minutes.

[0103] In Tables 1 and 2, "flatness" refers to the content explained in paragraphs 0042 to 0054. Furthermore, "metal bearing specific wear" and "fault material specific wear" in Tables 1 and 2, and "total wear" in Tables 1 to 3, refer to the content explained in paragraphs 0057 to 0062. For the purposes of this explanation, further details will be omitted.

[0104] (Abrasion test) Abrasion tests were conducted on samples No. "1" to "3" and "6" to "18," which are examples, and on samples No. "4" to "6," which are comparative examples.

[0105] Specifically, the wear test shown in Figure 8 was performed on one axial end face of the metal bearings of the examples and comparative examples under ambient temperature (25°C) and under ambient temperature (500°C). The method of the wear test and the calculation of the amount of wear were described in paragraphs 0057 to 0062.

[0106] Furthermore, the surface pressure "P" applied by the rotating shaft to one axial end face of the metal bearing in an atmosphere of 25°C is 1.0 (N / mm²). 2 The reciprocating rotational speed "V" of the rotating shaft is 0.044 (m / s), and the total rotational time "T" of the rotating shaft is 20 (h). Furthermore, the surface pressure "P" that the rotating shaft applies to one axial end face of the metal bearing in a 500°C atmosphere is 1.0 (N / mm²). 2 The reciprocating rotation speed "V" of the rotating shaft is 0.044 (m / s), and the total time "T" of the rotational motion of the rotating shaft is 65 (h).

[0107] (Test results) The results of the above wear tests are listed in Tables 1-3 as "Metal bearing specific wear," "Matching material specific wear," and "Total wear."

[0108] Furthermore, Figure 14 is a graph of the second item from the right in Table 3, namely, for comparative example samples "4", "3", and "5" under a 25°C atmosphere, and for example samples "14", "1", "15", "6", and "2" where the second metal wire is pure Ni under a 25°C atmosphere. The horizontal axis is "Ratio of the volume of the second metal wire to the volume of the first and second metal wires (Ni content: (%))" (simply abbreviated as "Ni content: (%)" in Figure 14), and the vertical axis is "Total wear amount".

[0109] Furthermore, Figure 15 is a graph of the first item from the right in Table 3, namely, for comparative example samples "4", "3", and "5" under a 500°C atmosphere, and for example samples "14", "1", "15", "6", and "2" where the second metal wire is pure Ni under a 500°C atmosphere, the horizontal axis is "the ratio of the volume of the second metal wire to the volume of the first and second metal wires (Ni content: (%))" (simply abbreviated as "Ni content: (%)" in Figure 15), and the vertical axis is "total wear amount".

[0110] As shown in Figure 14, under conditions of 25°C, braiding even a small amount of the second metal wire, which is made of Ni, with the first metal wire, which is made of stainless steel, tends to reduce the total amount of wear and significantly improve sliding properties.

[0111] Furthermore, the samples exhibiting the best sliding properties were Sample No. "1" (two stainless steel first metal wires and one pure nickel second metal wire), where the volume ratio of the second metal wire to the first and second metal wires was 33%, and Sample No. "15" (four stainless steel first metal wires and two pure nickel second metal wires).

[0112] Furthermore, as shown in Figure 15, under a 500°C atmosphere, the higher the proportion of the first metal wire made of stainless steel, the better the sliding properties tend to be.

[0113] It should be noted that the present invention is not limited to the embodiments described above, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of Symbols]

[0114] 10 Metal bearings 11 Inner surface 13 Outer surface 15 Axial end face 20 First metal wire 30 Second metal wire 70 seats 79 Adjustment Member

Claims

1. A cylindrical metal bearing, A metal bearing characterized in that a knitted fabric consisting of a first metal wire made of stainless steel and a second metal wire made of a different material from the first metal wire is compressed at least in the axial direction of the metal bearing.

2. The metal bearing according to claim 1, wherein the second metal wire is softer than the first metal wire.

3. The metal bearing according to claim 1 or 2, wherein the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing, is 2.2 to 39.8%.

4. The metal bearing according to claim 1 or 2, wherein the ratio of the volume of the second metal wire to the volumes of the first and second metal wires is 20 to 67%.

5. The metal bearing according to claim 1 or 2, wherein the second metal wire is made of at least one metal selected from pure Ni, Ni-based metals, pure Cu, and Cu-based metals.

6. A method for manufacturing a cylindrical metal bearing, A sheet forming process for forming a knitted sheet consisting of a first metal wire made of stainless steel and a second metal wire made of a different material from the first metal wire, A sheet winding step in which the aforementioned sheet is wound into a cylindrical shape, A method for manufacturing a metal bearing, comprising a sheet compression step of compressing the sheet, which is wound in a cylindrical shape, in at least the axial direction of the metal bearing such that the flatness ratio, which is the ratio of the flat portion to the total length of the sliding surface of the metal bearing, is 2.2 to 39.8%.

7. A sintering step of sintering the compressed metal bearing, A method for manufacturing a metal bearing according to claim 6, comprising a dimension adjustment step of adjusting the inner diameter of the metal bearing by bringing an adjustment member of a desired outer diameter into contact with the inner circumferential surface of the metal bearing while the outer circumferential surface of the sintered metal bearing is restrained, or adjusting the outer diameter of the metal bearing by bringing an adjustment member of a desired inner diameter into contact with the outer circumferential surface of the metal bearing while the inner circumferential surface of the sintered metal bearing is restrained.

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