Sliding member and method for manufacturing the same

Abstract

The present invention relates to a sliding member and a method for manufacturing the sliding member. One embodiment of the sliding member is a sliding member comprising a shaft member having a shaft diameter of 180 mm or greater and a bearing member having an inner peripheral surface capable of slidably supporting the outer peripheral surface of the shaft member, wherein, when the arithmetic mean roughness of the outer peripheral surface is Ra1 [μm], the contact ratio A between the outer peripheral surface and the inner peripheral surface is at Satisfies the following formula 1A at ≥3.04Ra1 0.78 …1.

Description

Technical Field

[0001] The present invention relates to a sliding member and a method for manufacturing the sliding member. Background Art

[0002] Shaft components such as crankshafts, intermediate shafts, and propeller shafts used in ships are slidably supported by bearing members such as plain bearings. Lubricating fluid is also supplied to the gap between the shaft and bearing components. This lubricating fluid forms a lubricating film between the shaft and bearing components, thereby preventing seizure. However, if the surface roughness of the shaft and bearing components is greater than the thickness of the lubricating film, seizure is more likely to occur between the two components.

[0003] As a technique for suppressing seizure of sliding members, a method of smoothing the sliding surface of a shaft member, etc. For example, Patent Document 1 describes a combined sliding member having surface characteristics that can cope with friction reduction in an internal combustion engine.

[0004] Patent Document 1 describes that friction reduction can be achieved by setting the surface roughness Rz of the sliding surface of the piston ring to 0.5 to 1.0 μm, the surface roughness Rz of the sliding surface of the cylinder liner to 0.5 to 1.5 μm, the initial wear height Rpk to 0.05 to 0.2 μm, the effective load roughness Rk to 0.2 to 0.6 μm, and the oil reservoir depth Rvk to 0.10 to 0.35 μm.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-116707 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In the manufacture of large sliding components for ships, it is difficult to achieve high precision in roundness and cylindricity of the shaft components due to bending of the shaft components during machining. Therefore, it may be difficult to achieve sufficient dimensional accuracy of the sliding components by machining alone.

[0010] Given this situation, when manufacturing large sliding components for ships, the sliding surfaces are often manually ground after machining. However, precisely controlling the surface shape of the sliding surfaces of such large sliding components using the method described in Patent Document 1 is impractical from a manufacturing cost perspective. Furthermore, among marine sliding components, bearings sometimes have low hardness, making grinding the sliding surfaces of these bearings difficult.

[0011] The present invention has been made in view of such circumstances, and an object thereof is to provide a sliding member capable of suppressing galling between a shaft member and a bearing member while suppressing an increase in manufacturing cost.

[0012] Means of solving the problem

[0013] A sliding member according to one embodiment of the present invention, which is proposed to solve the above-mentioned problems, comprises: a shaft member having a shaft diameter of 180 mm or more; and a bearing member having an inner peripheral surface capable of slidably supporting the outer peripheral surface of the shaft member, wherein, when the arithmetic mean roughness of the outer peripheral surface is set to Ra1 [μm], the contact ratio A between the outer peripheral surface and the inner peripheral surface is at The following formula 1 is satisfied.

[0014]

Formula 1

[0015] A at ≥3.04Ra1 0.78 ...1

[0016] Effects of the Invention

[0017] A sliding member according to one embodiment of the present invention can suppress an increase in manufacturing cost while suppressing seizure between a shaft member and a bearing member. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic cross-sectional view showing a sliding member according to one embodiment of the present invention, taken along a plane perpendicular to the axial direction of the shaft member.

[0019] Figure 2 This is a flowchart showing a method for manufacturing a sliding member according to one embodiment of the present invention.

[0020] Figure 3 This is a graph showing the relationship between the minimum film thickness ratio of No. 10, No. 11, and No. 12 and the surface pressure received by the bearing member.

[0021] Figure 4 This is a graph showing the relationship between the minimum film thickness ratio of No. 6, No. 7, and No. 9 and the surface pressure applied to the bearing member.

[0022] Figure 5 This is a graph showing the relationship between the minimum film thickness ratio of No. 8, No. 13, and No. 14 and the surface pressure received by the bearing member.

[0023] Figure 6 This is a graph showing the relationship between the minimum film thickness ratio and the maximum contact pressure for No. 6 to No. 14.

[0024] Figure 7Schematic cross-sectional views showing the cut surfaces including the central axes of the shaft members No. 6 to No. 9.

[0025] Figure 8 This is a schematic cross-sectional view showing a cut surface including the central axis of the shaft member No. 13.

[0026] Figure 9 This is a schematic cross-sectional view showing a cut surface including the central axis of the shaft member No. 14.

[0027] Figure 10 This is a graph showing the relationship between the arithmetic mean roughness of a shaft member and the seizure limit surface pressure.

[0028] Figure 11 This is a graph showing the relationship between the contact ratio between the shaft member and the bearing member and the seizure limit surface pressure.

[0029] Explanation of symbols

[0030] 1, 102, 103, 104 shaft components

[0031] 11 Outer Surface

[0032] 2 Bearing components

[0033] 21 Inner Surface

[0034] 3. Lubricating oil

[0035] 31 Oil film

[0036] D, D1, D2, D3 shaft diameter

[0037] P, P1, P2, P3 Center axis of shaft components

[0038] L1, L2 Axial length of the shaft component

[0039] L3 Axial length of the bearing component

[0040] L A1 、L A21 、L A22 、L A23 Width of the concave portion

[0041] L A31 、L A32 The shortening of the axial length of the shaft member

[0042] d1, d2: Depth of the concave portion DETAILED DESCRIPTION

[0043] [Description of Embodiments of the Invention]

[0044] First, embodiments of the present invention will be described below.

[0045] A sliding member according to one embodiment of the present invention comprises: a shaft member having a shaft diameter of 180 mm or more; and a bearing member having an inner peripheral surface capable of slidably supporting the outer peripheral surface of the shaft member, wherein, when the arithmetic mean roughness of the outer peripheral surface is Ra1 [μm], the contact ratio A between the outer peripheral surface and the inner peripheral surface is at The following formula 1 is satisfied.

[0046]

Formula 2

[0047] A at ≥3.04Ra1 0.78 ...1

[0048] Generally speaking, a high contact ratio between the outer circumference of the shaft member and the inner circumference of the bearing member results in low surface pressure on the inner circumference of the bearing member, thus easily preventing galling between the two members. By satisfying the aforementioned equation 1 in this sliding member, the contact ratio can be controlled to a value above the critical value for preventing galling. Furthermore, by using equation 1 in this sliding member, the need for precise control of the sliding surface shape is eliminated, thereby minimizing increases in manufacturing costs.

[0049] The arithmetic mean roughness Ra1 is preferably 0.20 μm or less. When the arithmetic mean roughness Ra1 is equal to or less than the upper limit, seizure between the shaft member and the bearing member can be more reliably suppressed.

[0050] The shaft member can be a crankshaft journal or crankpin. Because the crankshaft has eccentric portions, it is susceptible to deflection during machining. Therefore, achieving dimensional accuracy through machining alone is difficult, and manual grinding is required after machining. On the other hand, by using the above-mentioned formula 1, the sliding member does not require precise control of the surface shape of the sliding surface. Therefore, when the shaft member is a crankshaft journal or crankpin, increases in manufacturing costs can be effectively suppressed.

[0051] Another aspect of the present invention provides a method for manufacturing a sliding member comprising a shaft member having a shaft diameter of 180 mm or greater and a bearing member having an inner peripheral surface capable of slidably supporting the outer peripheral surface of the shaft member, wherein the method comprises: providing a contact ratio A between the outer peripheral surface and the inner peripheral surface of the shaft member with an arithmetic mean roughness of Ra1 [μm]; at The method of satisfying the above-mentioned formula 1 is to manually grind the above-mentioned outer peripheral surface through a grinding process.

[0052] This method of manufacturing a sliding member controls the contact ratio to a value above a critical value for suppressing galling by manually polishing the outer peripheral surface in the polishing step to satisfy the above-mentioned formula 1. Furthermore, by using the above-mentioned formula 1 in the polishing step, this method of manufacturing a sliding member eliminates the need for precise control of the surface shape of the sliding surface, thereby suppressing an increase in manufacturing costs.

[0053] In addition, in the present invention, the so-called "shaft diameter" means the diameter of the outer peripheral surface of the shaft component, and the so-called "arithmetic mean roughness" means the value measured in accordance with JIS-B0601 (2013) with a high-pass cutoff value (λc) of 0.8 mm and a low-pass cutoff value (λs) of 2.5 μm.

[0054] In the present invention, the so-called "contact ratio" means the ratio of the area of ​​the portion in contact with the bearing member to the total sliding area of ​​the outer peripheral surface of the shaft member when the outer peripheral surface of the shaft member is pressed against the inner peripheral surface of the bearing member at an arbitrary angle along the radial direction of the shaft member and the shaft member is rotated around its central axis.

[0055] [Details of Embodiments of the Invention]

[0056] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0057] [Sliding member]

[0058] Figure 1 The sliding member comprises: a shaft member 1 having a shaft diameter D of 180 mm or more; a bearing member 2 having an inner peripheral surface 21 that can slidably support the outer peripheral surface 11 of the shaft member 1; and lubricating oil 3. The central axis P of the shaft member 1 is in the horizontal direction ( Figure 1 The inner circumferential surface 21 of the bearing member 2 circumferentially surrounds the outer circumferential surface 11 of the shaft member 1. Lubricating oil 3 is supplied to the gap between the outer circumferential surface 11 of the shaft member 1 and the inner circumferential surface 21 of the bearing member 2. In addition, the lubricating oil 3 forms an oil film 31. In this way, the inner circumferential surface 21 faces the outer circumferential surface 11 via the oil film 31, thereby being able to slidably support the outer circumferential surface 11.

[0059] In the shaft member 1 having a shaft diameter of 180 mm or more, since it is difficult to improve the dimensional accuracy of the outer peripheral surface 11 by machining alone, after machining, a portion or all of the outer peripheral surface 11 is manually ground. Here, the so-called "manual grinding" means manual grinding using sandpaper or the like.

[0060] When the arithmetic mean roughness of the outer peripheral surface 11 (more specifically, the arithmetic mean roughness after manual polishing of the outer peripheral surface 11) is Ra1 [μm], the contact ratio A between the outer peripheral surface 11 and the inner peripheral surface 21 is atThe following formula 1 is satisfied. In addition, as the "arithmetic mean roughness Ra1", a value obtained by the following steps can be used. First, four circumferential positions are determined at intervals of 90 degrees along the circumference of the outer peripheral surface 11. Secondly, at each circumferential position, two measurement locations with different axial positions are determined. Then, at this measurement location, the arithmetic mean roughness measured with an evaluation length of 4 mm is averaged, and this value is obtained as the arithmetic mean roughness Ra1 of the outer peripheral surface 11. In addition, the above-mentioned evaluation length can be determined along a direction orthogonal to the direction of manual grinding. For example, when the outer peripheral surface 11 is ground circumferentially, the above-mentioned evaluation length can be determined along the axial direction of the shaft member 1.

[0061]

Formula 3

[0062] A at ≥3.04Ra1 0.78 ...1

[0063] As the contact rate A at The upper limit of is not particularly limited, but is preferably 0.90, more preferably 0.85, and further preferably 0.80. at If the contact rate A is higher than the upper limit, the amount of grinding will increase during manual grinding, which may make it impossible to suppress the manufacturing cost. at ", for example, can be obtained using a stretcher having a plane extending parallel to the axial direction of the shaft member 1, or a shell-shaped bearing model material having an inner peripheral surface that partially surrounds the outer peripheral surface 11 of the shaft member 1. at In the measurement method, after applying ink to the above-mentioned flat surface or the above-mentioned inner peripheral surface, the above-mentioned flat surface or the above-mentioned inner peripheral surface is pressed over the entire outer peripheral surface 11 of the shaft member 1 to transfer the ink. Thereafter, the ink-transferred portion is regarded as the contact portion between the outer peripheral surface 11 and the inner peripheral surface 21, and the contact rate A is determined based on the ink transfer rate. at When implementing the method using the stretcher or the method using the bearing model material, it is sufficient to use ink diluted with a diluent. For example, the red touch paste manufactured by Daizo Co., Ltd. can be diluted to a consistency of 250 or more and 300 or less as specified in JIS-K2220 (2013) and then used. The above-mentioned consistency can be adjusted according to the above-mentioned contact ratio A. atThe ink concentration is controlled by adjusting the ink temperature during measurement. Specifically, the concentration can be controlled as follows: when the ink temperature during measurement is between 0°C and 14°C, the ink concentration is 65%; when the temperature is between 14°C and 24°C, the ink concentration is 70%; and when the temperature is between 24°C and 40°C, the ink concentration is 75%. By applying the diluted ink to the stretcher or the bearing mold material in this manner, it is easier to accurately determine the microscopic irregularities on the outer peripheral surface 11 during ink transfer.

[0064] <Shaft member>

[0065] The shaft member 1 is a rotating body that rotates in the circumferential direction relative to the bearing member 2. Examples of the shaft member 1 include a marine crankshaft, an intermediate shaft, a propeller shaft, etc. that are arranged on a ship. Examples of the material of the shaft member 1 include carbon steel, low alloy steel, and aluminum alloy.

[0066] The shaft member 1 can be a journal or crank pin of a crankshaft. Since the crankshaft has many eccentric parts, it is easy to bend during machining. Therefore, it is difficult to improve the dimensional accuracy by machining alone. In particular, it is necessary to manually grind the outer peripheral surface 11 of the shaft member 1 after machining. On the other hand, by using the above-mentioned formula 1, the sliding member does not need to accurately control the surface characteristics of the sliding surface. Therefore, when the shaft member 1 is a journal or crank pin of a crankshaft, the sliding member can effectively suppress the increase in manufacturing costs.

[0067] The lower limit of the shaft diameter D of the shaft member 1 is 180 mm as mentioned above, but it can also be 280 mm or 360 mm. When the shaft diameter D of the shaft member 1 is above the above lower limit, it is difficult to improve the dimensional accuracy only by machining, and the outer peripheral surface 11 of the shaft member 1 needs to be manually ground after machining. On the other hand, it is difficult to strictly control the surface shape of the outer peripheral surface 11 of the shaft member 1 with a large diameter by manual grinding from the perspective of manufacturing cost, etc. In this regard, the sliding member does not need to accurately control the surface shape of the sliding surface by using the above formula 1. Therefore, even if the shaft diameter D of the shaft member 1 is above the above lower limit, the increase in manufacturing cost can be suppressed.

[0068] The upper limit of the shaft diameter D of the shaft member 1 is preferably 1500 mm, more preferably 1400 mm, and further preferably 1300 mm. If the shaft diameter D exceeds the upper limit, the sliding member becomes too large, which may violate requirements such as miniaturization of the device.

[0069] The lower limit of the Young's modulus of the shaft member 1 is preferably 190 GPa, more preferably 200 GPa, and further preferably 210 GPa. If the Young's modulus of the shaft member 1 is lower than the above lower limit, the deflection of the shaft member 1 during machining may become larger. As a result, the time required for manual grinding increases, and it may be difficult to fully suppress the manufacturing cost. On the other hand, the sliding member will have a particularly excellent effect in the case where the shaft member 1 deflects to some extent. From this point of view, the upper limit of the Young's modulus of the shaft member 1 is not particularly limited, for example, it can be 220 GPa.

[0070] The upper limit of the arithmetic mean roughness Ra1 of the outer peripheral surface 11 is preferably 0.20 μm, more preferably 0.16 μm, and even more preferably 0.08 μm. If the arithmetic mean roughness Ra1 exceeds the upper limit, it may be difficult to prevent galling between the outer peripheral surface 11 and the inner peripheral surface 21. On the other hand, the lower limit of the arithmetic mean roughness Ra1 can be 0.01 μm or even 0.04 μm, from the perspective of facilitating adjustment of the surface shape of the outer peripheral surface 11 by manual polishing.

[0071] The shaft member 1 may also have a peripheral separation portion at both ends of the axial direction that does not contact the bearing member 2. In other words, the outer peripheral surface 11 of the shaft member 1 may also be provided with a peripheral separation portion at both ends of the axial direction that does not contact the bearing member 2. at The non-contact portion that comes into contact with the measurement method. When the shaft member 1 is the above-mentioned journal or crankpin, this peripheral separation portion is likely to occur. In the structure of the sliding member having such a peripheral separation portion on the shaft member 1, it is easy to suppress seizure between the shaft member 1 and the bearing member 2.

[0072] On the outer peripheral surface 11 of the shaft member 1, there may also be a plurality of roughness protrusion vertices calculated by the following steps. First, based on a roughness curve of a measuring length of 4.0 mm measured in accordance with JIS-B0601 (2013) with a cutoff value of 0.25 mm, the average line of the roughness curve is set according to JIS-B0601 (2013). With the average line as a reference, the height of the measuring point located above the average line is defined as a positive value, and the height of the measuring point located below the average line is defined as a negative value. The average value of the heights of all measuring points with positive heights is taken as Thr0. Secondly, among the measuring points on the roughness curve, the measuring point that is higher than the measuring points adjacent to both sides and has a height greater than -Thr0 is taken as a hypothetical vertex. The measuring point with the smallest height (the greatest depth from the adjacent hypothetical vertex) among the measuring points located between adjacent hypothetical vertices is taken as a valley. Then, for all hypothetical vertices, the height difference between the hypothetical vertex and the valleys adjacent to it on both sides is calculated, and vertices where the larger of these height differences is less than 0.2×Thr0 are excluded. The remaining hypothetical vertices are then determined as roughness protrusion vertices.

[0073] When the apex of the roughness protrusion is present on the outer peripheral surface 11 of the shaft member 1, the lower limit of the radius of curvature of the roughness protrusion on the outer peripheral surface 11 can be 55 μm or 58 μm. If the above-mentioned manual grinding is performed, the radius of curvature of the roughness protrusion tends to increase. If the radius of curvature of the roughness protrusion is large, seizure is likely to occur between the outer peripheral surface 11 and the inner peripheral surface 21. Even with such a structure, this sliding member can easily suppress seizure between the outer peripheral surface 11 and the inner peripheral surface 21.

[0074] The "curvature radius of the roughness protrusion" is calculated using the following steps. First, a straight line is drawn from all measurement points between the vertex of the roughness protrusion and the valleys adjacent to it on both sides, toward the vertex of the roughness protrusion. The measurement point with the maximum gradient of this straight line is defined as the end of the roughness protrusion. The quadratic coefficient of the quadratic function obtained by fitting the roughness curve between the two ends of each roughness protrusion using the least squares method is used as a, and the curvature radius of each roughness protrusion is calculated as -0.5 / a. The median of the curvature radius of all roughness protrusions on the roughness curve is then determined as the curvature radius of the roughness protrusion.

[0075] If manual grinding is performed, as mentioned above, the curvature radius of the roughness protrusion of the outer peripheral surface 11 of the shaft component 1 is likely to become larger. In addition, with respect to other roughness characteristics of the outer peripheral surface 11, the roughness is also likely to become larger. In this case, by using sandpaper with a sufficiently large number, the arithmetic mean roughness Ra1 of the outer peripheral surface 11 can be reduced. For example, by grinding with sandpaper with a roughness of 200 or more, the arithmetic mean roughness Ra1 can be reduced to below 0.20 μm. The number of the above-mentioned sandpaper can be higher than 500 or higher than 600. As a grinding step performed by sandpaper, for example, a method of rotating the shaft component 1 and pressing the sandpaper against the outer peripheral surface 11 by hand, thereby grinding the outer peripheral surface 11 along the circumference of the outer peripheral surface 11 can be cited. In addition, in the case where it is difficult to grind the shaft component 1 while rotating, such as a marine crankshaft, a method of manually rubbing the outer peripheral surface 11 along the circumference of the outer peripheral surface 11 using sandpaper can be cited.

[0076] <Bearing components>

[0077] Examples of the bearing member 2 include marine crankshaft bearings, intermediate bearings, and propulsion bearings installed on ships. Examples of the material of the bearing member 2 include white metal, aluminum alloy, trimetal, and kelmet.

[0078] It is preferred that the hardness H1 [HV] of the shaft member 1 is greater than the hardness H2 [HV] of the bearing member 2. Generally speaking, since the hardness H2 of the bearing member 2 is small, it is difficult to intentionally control the surface roughness of the inner peripheral surface 21 by machining or the like. In this case, by making the hardness H1 of the shaft member 1 greater than the hardness H2 of the bearing member 2, the inner peripheral surface 21 of the bearing member 2 can be ground by sliding with the shaft member 1. As a result, the surface roughness of the inner peripheral surface 21 of the bearing member 2 is reduced, and it is easy to control the contact ratio A between the outer peripheral surface 11 and the inner peripheral surface 21. at . The lower limit of the ratio of the hardness H1 of the shaft member 1 to the hardness H2 of the bearing member 2 (H1 / H2) is preferably 4.1, more preferably 5.0, further preferably 6.0, and particularly preferably 8.0. If the above ratio is lower than the above lower limit, it may be difficult to reduce the surface roughness of the inner peripheral surface 21 by the rotation of the shaft member 1. On the other hand, there is no specific upper limit for the above ratio, but from the perspective of facilitating the selection of the materials of the shaft member 1 and the bearing member 2, it can be, for example, 20.

[0079] <Lubricating oil>

[0080] Examples of the lubricating oil 3 include paraffin-based base oils, etc. The lubricating oil 3 forms an oil film 31 , thereby making it easier to maintain a fluid lubrication state between the outer peripheral surface 11 and the inner peripheral surface 21 .

[0081] The lower limit of the viscosity of the lubricating oil 3 is preferably 4.8×10 －3 Pa·second, more preferably 9.8×10 －3 If the viscosity is lower than the lower limit, the seizure between the outer peripheral surface 11 and the inner peripheral surface 21 may not be sufficiently suppressed. On the contrary, the upper limit of the viscosity of the lubricating oil 3 is preferably 1.1×10 －1 Pa·second, more preferably 8.1×10 －2 Pa·second. If the viscosity is higher than the upper limit, the friction loss between the outer peripheral surface 11 and the inner peripheral surface 21 may not be sufficiently suppressed. The viscosity is calculated based on the temperature of the oil film 31 during stable driving of the shaft member 1. In addition, the term "during stable driving" means the time when the rotation of the shaft member 1 is maintained at a certain level, excluding the time when the rotation of the shaft member 1 starts and ends.

[0082] Advantages

[0083] The sliding member can control the contact ratio A by satisfying the above-mentioned formula 1. at In addition, by using the above formula 1, the sliding member does not need to precisely control the surface shape of the sliding surface, that is, to control the roughness characteristics other than the arithmetic mean roughness Ra1 within a specified range and to make the contact rate A at Therefore, the sliding member can control the seizure between the shaft member 1 and the bearing member 2 and can suppress an increase in manufacturing cost.

[0084] [Method for manufacturing a sliding member]

[0085] by Figure 2 Method for manufacturing a sliding member, manufacturing Figure 1 The manufacturing method of the sliding member includes a grinding step S1 of manually grinding the outer peripheral surface 11 of the shaft member 1.

[0086] <Grinding process>

[0087] In the polishing step S1, the contact ratio A between the outer peripheral surface 11 and the inner peripheral surface 21 is set to at The outer peripheral surface 11 is manually ground so as to satisfy the above formula 1. In the grinding step S1, the contact ratio A is increased so as to satisfy the above formula 1. at , or reduce the arithmetic mean roughness Ra1 of the outer peripheral surface 11, and grind the outer peripheral surface 11 in this way.

[0088] As a way to increase the contact rate atThe method includes, for example, using the above-mentioned stretcher or a shell-shaped bearing model material to determine the contact portion of the outer peripheral surface 11, and then partially grinding the contact portion to increase the overall contact rate between the outer peripheral surface 11 and the inner peripheral surface 21.

[0089] One method for reducing the arithmetic mean roughness Ra1 of the outer peripheral surface 11 is, for example, to polish the outer peripheral surface 11 using high-grade sandpaper. The sandpaper is preferably numbered 200 or higher, more preferably 500 or higher, and even more preferably 600 or higher. Using high-grade sandpaper in this manner makes it easier to reduce the arithmetic mean roughness Ra1 of the outer peripheral surface 11 so as to satisfy the above-mentioned formula 1.

[0090] Advantages

[0091] The manufacturing method of the sliding member can control the contact rate A by manually grinding the outer peripheral surface 11 in a manner satisfying the above formula 1 through the grinding step S1. at , reaching a critical value above which seizure can be suppressed. Furthermore, by using the above-mentioned formula 1 in the grinding step S1, this method for manufacturing a sliding member eliminates the need for precise control of the surface shape of the sliding surface. Therefore, this method for manufacturing a sliding member can suppress seizure between the shaft member 1 and the bearing member 2 while also minimizing increases in manufacturing costs.

[0092] [Other embodiments]

[0093] The above embodiments do not limit the configuration of the present invention. Therefore, the above embodiments may omit, replace, or add components of each part of the above embodiments based on the description in this specification and common technical knowledge, and all of these should be interpreted as falling within the scope of the present invention.

[0094] In the above embodiment, the central axis of the shaft member extends in the horizontal direction, but the central axis of the shaft member may be inclined with respect to the horizontal direction.

[0095] In the above embodiment, lubricating oil is supplied to the gap between the outer peripheral surface of the shaft member and the inner peripheral surface of the bearing member. However, lubricating fluids other than the above lubricating oil may be used in the sliding member. For example, seawater may be used as the above lubricating fluid.

[0096] Example

[0097] Hereinafter, the present invention will be described in detail based on examples, but the present invention is not to be construed as being limited by the description of these examples. In these examples, a bite test and a simulation test were performed.

[0098] [Bite test]

[0099] On a friction and wear testing machine manufactured by Kobelco, a shaft member and a bearing member having an inner peripheral surface that surrounds the outer peripheral surface of the shaft member throughout the entire circumference are fixed. Using the above-mentioned friction and wear testing machine, under the following structural conditions and operating conditions, the inner peripheral surface of the bearing member is pressed against the outer peripheral surface of the shaft member and the shaft member is rotated, and bite tests No. 1 to No. 5 are performed. The load applied to the shaft member by the bearing member is increased in stages to the maximum load from the start of the test. When bite occurs between the shaft member and the bearing member, the above-mentioned friction and wear testing machine is stopped, and the load of the stage before the load at this moment is taken as the limit load. In this bite test, the outer peripheral surface of the shaft member is manually ground by rotating the shaft member and pressing sandpaper against the outer peripheral surface of the shaft member by hand. By the manual grinding, the arithmetic mean roughness Ra1 of the outer peripheral surface of the shaft member and the contact rate between the shaft member and the bearing member are controlled. In this seizure test, since a shaft member with a relatively small diameter was used for the test, all of the following No. 1 to No. 5 were able to increase the contact rate between the shaft member and the bearing member to substantially 100%. The occurrence of seizure and the limit load in this seizure test are shown in Table 1.

[0100] <No.1>

[0101] In No. 1, as the shaft component, carbon steel with a Young's modulus of 210 GPa and a Poisson's ratio of 0.30 was used, and the shaft diameter was 48.00 mm (with a tolerance of -0.090 mm to -0.075 mm). The arithmetic mean roughness of the outer peripheral surface of the shaft component was controlled to 0.0765 μm. In addition, in No. 1 to No. 5, the arithmetic mean roughness of the outer peripheral surface of the shaft component was determined by the above-mentioned measurement method of the arithmetic mean roughness Ra1 along the evaluation length determined along the axial direction of the outer peripheral surface of the shaft component. As the bearing component, a sliding bearing manufactured by Daido Metal Industry Co., Ltd., consisting of a combination of an upper half component and a lower half component, was used. This sliding bearing was constructed of a white alloy equivalent to WJ1 as specified in JIS-H5401 (1958), with a Young's modulus of 55 GPa and a Poisson's ratio of 0.33. The inner diameter was 48.00 mm (with a tolerance of 0 mm to +1.05 mm), and the axial length of the inner surface (bearing width) was 15.6 mm. The arithmetic mean roughness of the inner surface of the bearing member was 0.8000 μm. The shaft member rotated at a constant speed of 3500 rpm. While the shaft member was rotating, ENEOS Co., Ltd.'s "FBK OIL RO32" lubricant was supplied between the outer surface of the shaft member and the inner surface of the bearing member. The lubricant was supplied at a temperature of 70°C using a circulating lubrication method. The load applied by the bearing member to the shaft member was 0.0 kN at the start of the test and increased in steps of 0.5 kN at 5-minute intervals to a maximum load of 20.0 kN.

[0102] <No.2>

[0103] In No. 2, a low alloy steel with a Young's modulus of 210 GPa and a Poisson's ratio of 0.30 is used as the shaft component, and the shaft diameter is 48.00 mm (tolerance is from -0.090 mm to -0.075 mm). The arithmetic mean roughness of the outer peripheral surface of the shaft component is controlled at 0.0680 μm. The bearing component is the same as No. 1. The rotation speed of the shaft component is fixed at 3500 rpm. In addition, lubricating oil is supplied between the outer peripheral surface of the shaft component and the inner peripheral surface of the bearing component in the same way as No. 1. The load applied by the bearing component to the shaft component is 0.0 kN at the beginning of the test and is increased by 5.0 kN at intervals of 5 minutes until the maximum load reaches 20.0 kN.

[0104] <No.3>

[0105] In No. 3, the arithmetic mean roughness of the outer peripheral surface of the shaft member was controlled to 0.1600 μm, and the other conditions were the same as those of No. 1.

[0106] No. 4

[0107] In No. 4, the arithmetic mean roughness of the outer peripheral surface of the shaft member was controlled to 0.4225 μm, and the other conditions were the same as those of No. 1.

[0108] <No.5>

[0109] In No. 5, the arithmetic mean roughness of the outer peripheral surface of the shaft member was controlled to 0.2450 μm, and the other conditions were the same as those of No. 2.

[0110]

Table 1

[0111]

[0112] As shown in Table 1, for shaft member No. 4, whose outer circumferential surface has an arithmetic mean roughness of 0.4225 μm, the limit load is 8.5 kN. This means that seizure occurred at a load of 9.0 kN. Furthermore, for shaft member No. 5, whose outer circumferential surface has an arithmetic mean roughness of 0.2450 μm, the limit load is 5.0 kN. This means that seizure occurred at a load of 10.0 kN. No. 1, No. 2, and No. 3, which did not experience seizure, satisfy the above equation 1. On the other hand, No. 4 and No. 5, which experienced seizure, do not satisfy the above equation 1.

[0113] [Simulation test]

[0114] In the simulation tests, the Excite Power Unit (EXCITE 2019 R1, AVL List GmbH) was used as software. The following structural and operating conditions were set to examine the sliding behavior of the shaft and bearing components. The analysis models for Nos. 6 to 14 below all used a single bearing model (joint: EHD2). Lubricant was supplied between the outer circumference of the shaft and the inner circumference of the bearing using a circulating lubrication system. Figure 3 The figure shows the relationship between the minimum film thickness ratio Λ of No.10, No.11 and No.12 and the surface pressure on the inner peripheral surface. Figure 4 The figure shows the relationship between the minimum film thickness ratio Λ of No.6, No.7 and No.9 and the surface pressure on the inner peripheral surface. Figure 5 The figure shows the relationship between the minimum film thickness ratio Λ and the surface pressure on the inner peripheral surface of No.8, No.13 and No.14. Figure 6 The relationship between the minimum film thickness ratio Λ and the maximum contact pressure of No. 6 to No. 14 is shown in FIG. Here, the so-called "minimum film thickness ratio" means that the minimum oil film thickness of the lubricating oil is h min [μm], assuming that the arithmetic mean roughness of the outer peripheral surface of the shaft component is Ra1 [μm], and the arithmetic mean roughness of the inner peripheral surface of the bearing component is Ra2 [μm], the value calculated by the following formula 2, the so-called "maximum contact pressure" means the maximum pressure when the outer peripheral surface of the shaft component and the inner peripheral surface of the bearing component are in solid contact.

[0115]

Formula 4

[0116]

[0117] No. 6

[0118] In No.6, use Figure 7 The shaft component 102 is set to the following structural conditions and operating conditions.

[0119] (Constitutional conditions)

[0120] Shaft member: As the shaft member 102, the axial length L1 is 15.6mm, the shaft diameter D1 is 48.0mm, and the use rigidity is 205000N / mm 2, steel with a Poisson's ratio of 0.30. The arithmetic mean roughness Ra1 of the outer peripheral surface of the shaft component 102 is 0.40μm, and the root mean square roughness Rq1 obtained by multiplying this arithmetic mean roughness Ra1 by 1.3 is 0.520μm. As the roughness parameters (Summit Roughness, Mean Summit Height and Elastic Factor) input into the software, the value of the above-mentioned arithmetic mean roughness Ra1 is converted by the following steps. First, 6 small shaft components (shaft diameter 39.96mm, axial length 42mm) are prepared, and each outer peripheral surface is manually polished so that the arithmetic mean roughness Ra of the outer peripheral surface is different values ​​in the range of approximately 0.07μm to 0.60μm. The above-mentioned arithmetic mean roughness Ra is determined along the axial direction of the outer peripheral surface of the small shaft component. The evaluation length is determined and obtained according to the above-mentioned measurement method of the arithmetic mean roughness Ra1. In addition, based on the waveform data obtained when measuring the above-mentioned arithmetic mean roughness Ra, the above-mentioned roughness parameters are obtained in accordance with the definition in the operating manual of the software. Then, a regression equation representing the relationship between the above-mentioned arithmetic mean roughness Ra and the above-mentioned roughness parameters is derived, and through the regression equation, the specified arithmetic mean roughness Ra1 is replaced with the corresponding above-mentioned roughness parameters. In the following No. 7 to No. 14, the roughness parameters of the shaft components used as the output software also use the values ​​converted by the above-mentioned method. The outer peripheral surface of the shaft component 102 has an annular recess extending in its circumferential direction. The recess has a cross section with a width (axial length of the shaft component 102) of L A1 [mm], a rectangle with a depth of d1 [mm]. In the axial direction of the shaft member 102, the distance from both ends of the shaft member 102 to the above-mentioned recess is equal. The depth d1 of the above-mentioned recess is 10μm. The above-mentioned recess is the detached portion around the shaft member 102 that does not come into contact with the bearing member when the shaft member 102 rotates. Therefore, the contact rate A between the shaft member 102 and the bearing member is at By (L1-L A1 ) / L1. The width of the concave portion L A1 As the contact rate A at is a value of 0.6.

[0121] Bearing component: As a bearing component, the axial length of the inner circumference (bearing width) is 15.6mm, the radial clearance with the shaft component is 0.047mm, and the rigidity is 5000N / mm 2, a white alloy with a Poisson's ratio of 0.33. The arithmetic mean roughness Ra2 of the inner circumferential surface of the bearing component is set to 0.40 μm. The root mean square roughness Rq2, calculated by multiplying this arithmetic mean roughness Ra2 by 1.3, is 0.520 μm. The roughness parameter input into the software is the value obtained by converting the arithmetic mean roughness Ra2 to the corresponding roughness parameter using the aforementioned regression equation. In the following examples No. 7 through No. 14, the values ​​converted using this method are also used as the roughness parameters of the bearing component input into the software.

[0122] (Working Conditions)

[0123] Rotational speed: The rotational speed of the shaft member 102 was set to 3500 rpm.

[0124] Load: The load on the inner circumference of the bearing component is increased in stages from 0.1 kN to 200 kN.

[0125] Lubricating oil: density is 871kg / m 3 , the lubricating oil has a specific heat of 2083 J / (kg·K). In addition, the viscosity of the lubricating oil is fixed at 9.8×10 －3 Pa·second. This viscosity is equivalent to the viscosity of FBK-RO32OIL manufactured by ENEOS at 70°C.

[0126] Model for solid contact: When the shaft member and the bearing member are in solid contact, an ideal elastic-plastic body with a yield stress of 200 MPa is used as a plastic deformation model for surface roughness protrusions.

[0127] No. 7

[0128] In No.7, use Figure 7 The shaft member 102 is provided with the following structural conditions. In addition, the operating conditions are the same as those of No. 6.

[0129] (Constitutional conditions)

[0130] Shaft member: The arithmetic mean roughness Ra1 of the outer peripheral surface is set to 0.08 μm, the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 is set to 0.104 μm, and the width L of the concave portion is set to A1 The contact rate A at The value is 0.7, and the structure is the same as No. 6 except for this.

[0131] Bearing member: The structure is the same as that of No. 6 except that the arithmetic mean roughness Ra2 of the inner peripheral surface is 0.08 μm and the root mean square roughness Rq2 obtained by multiplying the arithmetic mean roughness Ra2 by 1.3 is 0.104 μm.

[0132] No. 8

[0133] In No.8, use Figure 7 The shaft member 102 is provided with the following structural conditions. In addition, the operating conditions are the same as those of No. 6.

[0134] (Constitutional conditions)

[0135] Shaft member: The arithmetic mean roughness Ra1 of the outer peripheral surface is set to 0.20 μm, the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 is set to 0.260 μm, and the width L of the concave portion is set to A1 The contact rate A at The value is 0.7, and the structure is the same as No. 6 except for this.

[0136] Bearing member: The structure is the same as that of No. 6 except that the arithmetic mean roughness Ra2 of the inner peripheral surface is 0.20 μm and the root mean square roughness Rq2 obtained by multiplying the arithmetic mean roughness Ra2 by 1.3 is 0.260 μm.

[0137] No. 9

[0138] In No.9, use Figure 7 The shaft member 102 and the bearing member are the same as those of No. 6. In addition, the operating conditions are the same as those of No. 6.

[0139] (Constitutional conditions)

[0140] Shaft member: Make the width L of the recess A1 The contact rate A at The value is 0.7, and the structure is the same as No. 6 except for this.

[0141] No. 10

[0142] In No. 10, the following structural conditions were set. In addition, the operating conditions were the same as those in No. 6.

[0143] (Constitutional conditions)

[0144] Shaft component: As a shaft component, the axial length is 15.6mm, the shaft diameter is 48.0mm, and the service rigidity is 205000N / mm 2 , steel with a Poisson's ratio of 0.30. The arithmetic mean roughness Ra1 of the outer peripheral surface of the shaft member is set to 0.08 μm, and the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 is 0.104 μm. The outer peripheral surface of the shaft member has no concave portion, and the contact ratio A at is 1.0.

[0145] Bearing member: The structure is the same as that of No. 6 except that the arithmetic mean roughness Ra2 of the inner peripheral surface is set to 0.08 μm and the root mean square roughness Rq2 obtained by multiplying the arithmetic mean roughness Ra2 by 1.3 is 0.104 μm.

[0146] No. 11

[0147] In No. 11, the following structural conditions were set. In addition, the operating conditions were the same as those in No. 6.

[0148] (Constitutional conditions)

[0149] Shaft member: The structure was the same as that of No. 10 except that the arithmetic mean roughness Ra1 of the outer peripheral surface was 0.20 μm and the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 was 0.260 μm.

[0150] Bearing member: The structure is the same as that of No. 6 except that the arithmetic mean roughness Ra2 of the inner peripheral surface is 0.20 μm and the root mean square roughness Rq2 obtained by multiplying the arithmetic mean roughness Ra2 by 1.3 is 0.260 μm.

[0151] No. 12

[0152] In No. 12, the following configuration conditions were set. Otherwise, the operating conditions were the same as in No. 6.

[0153] (Constitutional conditions)

[0154] Shaft member: The structure was the same as that of No. 10 except that the arithmetic mean roughness Ra1 of the outer peripheral surface was set to 0.40 μm and the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 was set to 0.520 μm.

[0155] Bearing member: Use the same bearing member as No.6.

[0156] No. 13

[0157] In No.13, use Figure 8 The shaft member 103 is provided with the following structural conditions. In addition, the operating conditions are the same as those of No. 6.

[0158] (Constitutional conditions)

[0159] Shaft member: As the shaft member 103, the axial length L2 is 15.6mm, the shaft diameter D2 is 48.0mm, and the use rigidity is 205000N / mm 2, steel with a Poisson's ratio of 0.30. The arithmetic mean roughness Ra1 of the outer peripheral surface of the shaft member 103 is 0.20 μm, and the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 is 0.260 μm. The outer peripheral surface of the shaft member 103 has three annular recesses extending in its circumferential direction. These recesses have a cross-section with a width (the length of the shaft member 103 in the axial direction) of L and L respectively. A21 [mm], L A22 [mm], L A23 [mm], the depth is d2 [mm], and the width of the concave part is L A21 , L A22 and L A23 The above recesses are arranged at equal intervals in the axial direction of the shaft member 103. The depth d2 of the above recesses is 10 μm. The above recesses are the circumferential separation portions that do not come into contact with the bearing member when the shaft member 103 rotates. Therefore, the contact ratio A between the shaft member 103 and the bearing member is at (L2-L A21 -L A22 -L A23 ) / L2. The width of the concave portion L A21 , L A22 and L A23 The contact rate A at A value of 0.7.

[0160] Bearing member: The structure is the same as that of No. 6 except that the arithmetic mean roughness Ra2 of the inner peripheral surface is 0.20 μm and the root mean square roughness Rq2 obtained by multiplying the arithmetic mean roughness Ra2 by 1.3 is 0.260 μm.

[0161] No. 14

[0162] In No.14, use Figure 9 The shaft member 104 is provided with the following structural conditions. In addition, the operating conditions are the same as those of No. 6.

[0163] (Constitutional conditions)

[0164] Shaft member: The axial length of the shaft member 104 is controlled to be smaller than the axial length L3 of the inner circumference of the bearing member (bearing width L3). That is, the axial length of the shaft member 104 at both ends is shortened by L compared to the inner circumference. A31 [mm], L A32 [mm]. Shortened axial length L A31 and L A32 The shaft member 104 is similar to a shaft member having a circumferential separation portion at both ends. The axial length of the shaft member 104 is L3-L A31 -L A32[mm], shaft diameter D3 is 48.0mm, and the service rigidity is 205000N / mm 2 , steel with a Poisson's ratio of 0.30. The arithmetic mean roughness Ra1 of the outer peripheral surface of the shaft member 104 is set to 0.20 μm, and the root mean square roughness Rq1 obtained by multiplying the arithmetic mean roughness Ra1 by 1.3 is 0.260 μm. The contact ratio A between the shaft member 104 and the bearing member is at , with (L3-L A31 -L A32 ) / L3 calculation. In addition, L A31 and L A32 The contact rate A at A value of 0.7.

[0165] Bearing member: The structure was the same as that of No. 6, except that the arithmetic mean roughness Ra2 of the inner circumferential surface was set to 0.20 μm, and the root mean square roughness Rq2, obtained by multiplying the arithmetic mean roughness Ra2 by 1.3, was set to 0.260 μm. Specifically, the axial length L3 of the inner circumferential surface of the bearing member was set to 15.6 mm.

[0166] like Figure 3 As shown, at contact rate A at In the comparison of No.10, No.11 and No.12, which are equal to 1.0, for the same surface pressure, the smaller the arithmetic mean roughness Ra1, the larger the minimum film thickness ratio Λ. Figure 4 In the figure, for the same surface pressure, the minimum film thickness ratio Λ is larger for No.7 with a small arithmetic mean roughness Ra1 than for No.6 and No.9 with large arithmetic mean roughness Ra1. at No.6 is 0.6, contact rate A at For No.9 with a value of 0.7, the minimum film thickness is larger than Λ for the same surface pressure. Figure 5 In the middle, contact rate A at Comparison of No. 8, No. 13, and No. 14, which have the same arithmetic mean roughness Ra1, reveals that the minimum film thickness ratio Λ differs due to the different arrangements of the detached portions on the periphery.

[0167] Figure 6 The tendency shown is that the maximum contact pressure does not depend on the contact ratio A at , arithmetic mean roughness Ra1 and the arrangement of the detached parts around the periphery, but is uniquely determined by the minimum film thickness ratio Λ. Therefore, the size of the minimum film thickness ratio Λ can be used as an indicator of the anti-seizure resistance between the shaft member and the bearing member. In addition, as the arithmetic mean roughness Ra1 is smaller, the contact ratio A at The larger the minimum film thickness ratio Λ is, the smaller the arithmetic mean roughness of the sliding member in this simulation test is, and the contact rate A atThe larger the value, the better the seizure resistance.

[0168] The limit load of No. 4 in the seizure test was 8.5 kN, which is equivalent to 11.4 MPa when converted to surface pressure. Therefore, in No. 4, seizure is considered to occur under the condition of surface pressure of about 12.0 MPa. On the other hand, the condition of No. 4 corresponds to the arithmetic mean roughness Ra1 of the shaft member being 0.40 μm and the contact ratio A at No.12 is 1.0. Figure 3 , in No.12, the minimum film thickness ratio Λ is 2.2 when the surface pressure is 12.0MPa. When the minimum film thickness ratio Λ is 2.2, it generally meets the range of the minimum film thickness ratio Λ at which galling occurs, that is, less than 3. In addition, if we refer to Figure 6 , the maximum contact pressure occurs when the minimum film thickness ratio Λ is around 2.2. Therefore, in this simulation test, seizure occurs at the surface pressure when the minimum film thickness ratio Λ is 2.2. That is, the surface pressure when the minimum film thickness ratio Λ is 2.2 is set as the seizure limit surface pressure P lim [MPa].

[0169] Figure 10 are respectively Figure 3 、 Figure 4 and Figure 5 In the figure, the surface pressure when the minimum film thickness ratio Λ is 2.2 is read as the seizure limit surface pressure, the horizontal axis is the arithmetic mean roughness, and the vertical axis is the seizure limit surface pressure P lim And the graph drawn. In addition, Figure 10 The curve of means the power approximation of the plotted value. at When the arithmetic mean roughness of the outer peripheral surface of the shaft member is Ra1 [μm], the seizure limit surface pressure P lim Approximately -1.44 power of Ra1. On the other hand, when the contact ratio A of the shaft member 102 is used at When the seizure limit pressure P is 0.7, lim Approximately Ra1 to the power of -1.39. This shows that the seizure limit surface pressure P lim Untouched rate A at The influence of the roughness is proportional to the -1.4 power of the arithmetic mean roughness Ra1.

[0170] Figure 11 are respectively Figure 3 、 Figure 4 and Figure 5 The surface pressure when the minimum film thickness ratio Λ is 2.2 is read as the bite limit surface pressure, and the horizontal axis is the contact rate A. at , the vertical axis is the seizure limit surface pressure P lim And the graph drawn. In addition, Figure 10 The curve is the power approximation of the plotted value. Under the condition that the arithmetic mean roughness Ra1 of the shaft member 102 is 0.08 μm, the seizure limit surface pressure P lim Approximately 3.24th power of Ra1. Under the condition that the arithmetic mean roughness Ra1 of the shaft member 102 is 0.20 μm, the seizure limit surface pressure P lim Approximately 3.44th power of Ra1. Under the condition that the arithmetic mean roughness Ra1 of the shaft member 102 is 0.40 μm, the seizure limit surface pressure P lim Approximately 2.91 power of Ra1. This shows that the seizure limit surface pressure P when using the shaft member 102 is lim , is not affected by the arithmetic mean roughness Ra1, but is related to the contact rate A at is proportional to approximately the 3.2th power of .

[0171] On the other hand, under the condition that the arithmetic mean roughness Ra1 of the shaft member 103 used is 0.20 μm, the seizure limit surface pressure P lim Approximately 6.10 power of Ra1. In addition, under the condition that the arithmetic mean roughness Ra1 of the shaft member 104 is 0.20 μm, the seizure limit surface pressure P lim Approximately Ra1 raised to the power of 1.77.

[0172] According to about Figure 10 and Figure 11 The above research believes that the arithmetic mean roughness Ra1[μm] and contact rate A at For the seizure limit surface pressure P lim [MPa] contributes independently. Therefore, it is estimated that the seizure limit surface pressure P lim It is calculated by the following formula 3. In the following formula 3, α, β, and γ are constants determined by the shape of the shaft member.

[0173]

Formula 5

[0174] P lim =αRa1 β A at γ ...3

[0175] Seizure limit surface pressure P based on simulation test lim The values ​​of α, β, and γ in the above formula 3 are derived based on the values ​​of α. As a result, when the shaft member 102 is used, α = 3.6, β = -1.4, and γ = 3.2 in the above formula 3; when the shaft member 103 is used, α = 3.6, β = -1.4, and γ = 6.1 in the above formula 3; and when the shaft member 104 is used, α = 3.6, β = -1.4, and γ = 1.8 in the above formula 3.

[0176] In the above formula 3, the seizure limit surface pressure P lim Under the condition of being sufficiently large, it is believed that the seizure between the shaft member and the bearing member can be suppressed. For example, if the maximum load of 20kN in the seizure test is converted into a surface pressure of 26.71MPa, then P lim ≥26.71 can be used as a condition for suppressing seizure. This condition is obtained by using the above formula 3 to form the following formula 4.

[0177]

Formula 6

[0178]

[0179] During the manufacturing process of ship crankshafts, if the contact between the shaft member and the bearing member after machining is poor, separation often occurs around both ends of the shaft member. Therefore, substituting the parameters for shaft member 104, namely, α = 3.6, β = -1.4, and γ = 1.8, into Equation 4 above yields Equation 1.

[0180] Industrial Applicability

[0181] The sliding member according to one embodiment of the present invention can suppress the manufacturing cost and prevent seizure between the shaft member and the bearing member, and is therefore suitable for use as a sliding member for ships, for example.

Claims

1. A sliding member comprising: Shaft components with a shaft diameter of 180 mm or more and 1500 mm or less; a bearing member having an inner peripheral surface that slidably supports the outer peripheral surface of the shaft member, in, The shaft component is a marine crankshaft, intermediate shaft or propeller shaft, When the arithmetic mean roughness of the outer peripheral surface is Ra1, the contact rate A between the outer peripheral surface and the inner peripheral surface is at Satisfies the following formula 1, the unit of Ra1 is μm, A at ≥3.04 Ra1 0.78 …1.

2. The sliding member according to claim 1, wherein The arithmetic mean roughness Ra1 is 0.20 μm or less.

3. The sliding member according to claim 1 or claim 2, wherein: The shaft member is a journal or a crank pin of a crankshaft.

4. A method for manufacturing a sliding member, wherein: The sliding member comprises: a shaft member having a shaft diameter of 180 mm or more and 1500 mm or less, which is a crankshaft, intermediate shaft, or propeller shaft for a ship; and a bearing member having an inner peripheral surface that slidably supports the outer peripheral surface of the shaft member. The manufacturing method of the sliding member comprises the following grinding process: When the arithmetic mean roughness of the outer peripheral surface is Ra1, the contact rate A between the outer peripheral surface and the inner peripheral surface is at The outer peripheral surface is manually ground in a manner that satisfies the following formula 1, where the unit of Ra1 is μm: A at ≥3.04 Ra1 0.78 …1.

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