Shaft member for sliding bearing and method for manufacturing same

Abstract

A method of forming an antifriction layer (3 ') on a shaft member (1) using a hot isostatic pressing process, comprising the steps of: 1) providing a sheath (5) having an inner space in accordance with the shape of an integral blank in which the shaft member (1) and the antifriction material (3) are intended to form; 2) assembling the shaft component (1) and the antifriction material (3) in a sheath (5) according to the shape requirement of the integrated blank; (3) degassing and sealing the sheath, and enabling the residual pressure in the sheath to be lower than a preset vacuum pressure threshold value; (4) hot isostatic pressing treatment is conducted on the sheath provided with the shaft component and the antifriction material, so that metallurgical bonding of the antifriction material and the shaft component is achieved; and (5) the sheath is removed, and follow-up machining is conducted on the integrated blank obtained after metallurgical bonding according to needs. Wherein the anti-attrition material is a metal foil made of an anti-attrition metal material. In addition, the invention also provides a shaft member (1) formed by adopting the method and a sliding bearing (10) comprising the shaft member.

Description

Technical Field

[0001] This invention relates to a shaft component of a sliding bearing and a method for manufacturing such a shaft component. Background Technology

[0002] A bearing in which a bearing surface is formed between sliding components is called a sliding bearing. Structurally, sliding bearings do not have rolling elements; they use surface contact instead of point contact, resulting in a simple structure and stable load-bearing capacity. According to the direction of load transmission, sliding bearings can be divided into radial sliding bearings (also known as "radial sliding bearings") and axial sliding bearings (also known as "thrust sliding bearings"). Typically, a radial sliding bearing consists of a support member such as a bearing bush or bearing shell and a shaft member that can rotate relative to the support member. For example, the simplest sliding bearing can consist of a shaft that rotates within a hole.

[0003] To improve friction, a bearing liner made of friction-reducing material can be added between the shaft component and the support component. The bearing liner generally has a low coefficient of friction and good wear resistance. Figure 1 This diagram shows a cross-sectional view of a sliding bearing including a bearing bushing. As can be seen, the shaft member 1 mates with the support member 2 via the bearing bushing 3 (more precisely, the shaft member 1 mates with the inner hole 2a of the support member 2 via the bearing bushing 3), thus forming a radial sliding bearing 10 together with the support member 2. In the presence of lubricant, the bearing bushing 3 minimizes friction between the shaft member 1 and the support member 2. To simplify the structure, the bearing bushing 3 can also be integrally formed with the shaft member 1, thereby directly forming a friction-reducing layer 3' on the surface of the shaft member 1, as described in detail below.

[0004] Currently, laser cladding technology is a popular method for forming anti-friction layers on shaft components. "Laser cladding" refers to a coating technique that forms a coating of the selected material (e.g., metal powder) on a target surface by feeding it into a molten pool formed by a laser beam scanning the workpiece surface. A disadvantage of laser cladding is that the metal powder exists in the coating in the form of grains. Due to the porosity between these grains, the material has high porosity, resulting in low coating density. For example, after forming a powder coating from copper powder using laser cladding, its mass density can only reach 8.0 g / cm³. 3 It is significantly lower than the standard density of copper, 8.9 g / cm³. 3 This leads to varying degrees of decrease in the wear resistance and load-bearing capacity of the powder coating.

[0005] The reality calls for a method that can form a dense anti-friction layer on shaft components to obtain better tribological properties. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for forming a friction-reducing layer on a shaft member of a sliding bearing. The shaft member is configured to rotate relative to a support member of the sliding bearing. The friction-reducing layer is formed on the outer surface of the shaft member by metallurgical bonding of a friction-reducing material under hot isostatic pressing (HIP) conditions, at least partially covering the journal position where the shaft member contacts the support member. The HIP process includes the following sequential steps: Step 1) providing a sleeve having an internal space consistent with the shape of an integral blank formed from the shaft member and the friction-reducing material; Step 2) assembling the shaft member and the friction-reducing material into the sleeve according to the shape requirements of the integral blank; Step 3) degassing and sealing the sleeve so that the residual pressure inside is below a predetermined vacuum pressure threshold; Step 4) subjecting the sleeve containing the assembled shaft member and friction-reducing material to HIP treatment, achieving metallurgical bonding between the friction-reducing material and the shaft member; and Step 5) removing the sleeve and performing subsequent processing on the metallurgically bonded integral blank as needed. The friction-reducing material is a metal foil made of a friction-reducing metal material.

[0007] The friction-reducing layer formed by the above method has the advantages of high density and low defect rate, which can overcome the problems of loose material and high porosity commonly found in traditional additive manufacturing, and fundamentally eliminate the adverse effects of loose material on the tribological properties of the friction-reducing layer.

[0008] Based on the above method, the present invention also provides a shaft member and a sliding bearing comprising the shaft member.

[0009] Friction-reducing layers formed using wear-resistant metal foil under hot isostatic pressing (HIP) conditions exhibit improved wear resistance and service life compared to friction-reducing layers formed using powder materials under additive manufacturing conditions. When using metal foil as the friction-reducing material, the resulting friction-reducing layer inherits the zero porosity and 100% density of the metal foil, offering significant technical advantages over friction-reducing layers formed using powder materials.

[0010] The various embodiments and beneficial technical effects of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0011] Figure 1 Showing a cross-sectional schematic diagram of a sliding bearing containing shaft components;

[0012] Figure 2 A schematic diagram showing a method for forming a friction-reducing layer on the outer surface of a shaft component under hot isostatic pressing;

[0013] Figure 3A A schematic diagram showing the structure of the display shaft component with circumferential lubrication grooves formed on its surface; and

[0014] Figure 3B This is a schematic diagram showing a shaft component with axial lubrication grooves formed on its surface. Detailed Implementation

[0015] In the following description, the same or similar reference numerals are always used to denote the same or similar parts. Furthermore, terms indicating direction, such as “axial,” “radial,” and “circumferential (direction),” unless otherwise specified or indicated, refer to the axial, radial, and circumferential (directions) of the part being described.

[0016] Hot isostatic pressing (HOP) is a metallurgical process that applies equal pressure in all directions to a sample (e.g., a metal or ceramic) under high temperature and high pressure conditions, thereby sintering the sample into a dense billet. The "isostatic pressing" is typically achieved by applying uniform pressure to the sample using a fluid (typically an inert gas) within a closed chamber. The resulting billet has advantages such as stable composition, high density, good mechanical isotropy, and low cost.

[0017] Figure 2 This diagram illustrates a method for forming a friction-reducing layer on the (radial) outer surface of a shaft member using hot isostatic pressing (HIP). The innermost layer of the illustrated structure is a standard cylindrical solid shaft member 1. Typically, shaft member 1 can be made of medium- or low-carbon steel or low-alloy steel. Depending on the application requirements, shaft member 1 can also have other shapes, such as cylindrical structures with not perfectly uniform outer diameters. The middle layer of the illustrated structure is a friction-reducing material 3, used to form a friction-reducing layer 3' in the subsequent HIP process.

[0018] In this invention, the anti-friction material 3 is in the form of a metal foil, covering the radial outer surface of the shaft member 1. The anti-friction material 3 can be a copper or copper alloy anti-friction metal foil, wherein the copper alloy mainly includes bronze, brass, and cupronickel. Under the high temperature and high pressure conditions of hot isostatic pressing, the anti-friction material 3 and the shaft member 1 undergo metallurgical bonding to form an integrated shaft member. The outermost layer of the illustrated structure is a sheath 5, which is usually made of materials such as metal (e.g., carbon steel, stainless steel), ceramic, or glass. Under hot isostatic pressing conditions, the sheath 5 adheres to the surface of the inner blank, applying uniform static pressure from all directions to the shaft member 1 and the anti-friction material 3.

[0019] The following combination Figure 2 The present invention describes step-by-step a method for forming a friction-reducing layer on a shaft component using hot isostatic pressing:

[0020] Step 1) Provide a sleeve 5 such that the sleeve 5 has an internal space consistent with the shape of the integral blank to which the shaft member 1 and the friction-reducing material 3 are intended to be formed;

[0021] Step 2) Assemble the shaft component 1 and the friction-reducing material 3 into the sleeve 5 according to the shape requirements of the integrated blank;

[0022] Step 3) After degassing (vacuuming) the casing 5, seal it so that the pressure of the residual gas inside is lower than the predetermined vacuum pressure threshold, for example, less than 10. -3 MPa;

[0023] Step 4) Perform hot isostatic pressing on the sleeve 5, which is equipped with shaft member 1 and friction-reducing material 3, to achieve metallurgical bonding between friction-reducing material 3 and shaft member 1; and

[0024] Step 5) Remove the sleeve 5 and perform subsequent processing on the integrated blank after metallurgical bonding as needed.

[0025] As mentioned above, as an important feature of this invention, the friction-reducing material 3 can be directly made of friction-reducing metal foil, such as copper foil or copper alloy foil, and wrapped around the radial outer surface of the component 1. The metal foil can be prefabricated into a profile with uniform specifications, such as a sleeve with a specific aperture and length, the shape of which is at least partially adapted to the journal position of the shaft component 1. The prefabricated profile is assembled onto the shaft component (1) at the latest in step two, and is therefore particularly suitable for being assembled together with the shaft component (1) in the sleeve (5). Depending on the requirements of the sliding bearing, the sleeve 3 should at least cover the journal position of the shaft component 1.

[0026] Table 1

[0027]

[0028] Table 1 shows the test results of the anti-friction layer formed by bronze alloy foil (CuSn6) on the surface of 42CrMo alloy steel. The thickness of the bronze alloy foil ranged from 0.5 to 2 mm, and it was metallurgically bonded to the shaft material under hot isostatic pressing. The measured average interfacial bonding strength between the two was 184 MPa, the average hardness of the alloy layer was 100 HV1, the grain size was 0–1000 μm, and the porosity was 0%. After 1161 cycles of friction and wear testing, the coefficient of friction stabilized at 0.08, and the wear thickness was 2 μm, which fully meets the application requirements of sliding bearings.

[0029] The above describes a specific implementation method for forming a friction-reducing layer using metal foil (especially in the form of prefabricated profiles) under hot isostatic pressing conditions. Since metal foil can be processed into prefabricated profiles, it not only offers ease of assembly, but its material properties can also be controlled through pre-selection, ensuring that the performance of the formed friction-reducing layer meets expectations. Experimental results show that the friction-reducing layer formed from metal foil can achieve zero porosity and 100% density, fully realizing the maximum allowable load-bearing capacity and optimal tribological properties of the friction-reducing material.

[0030] Figure 3A and 3B The diagrams show different types of lubrication grooves formed on the surface of the shaft member. As shown, lubrication grooves 7a and 7b are designed to store lubricant to reduce friction between the shaft member 1 and the support member 2. The method of forming an anti-friction layer using a metal foil profile can effectively avoid the lubrication grooves 7a and 7b on the surface of the shaft member 1. Specifically, an opening or space corresponding to the lubrication groove is formed in the metal foil profile (e.g., a sleeve profile) beforehand, and the opening or space is aligned with the lubrication groove of the shaft member at the latest in step two mentioned above.

[0031] by Figure 3A In the example shown, the shaft member 1 has continuous lubrication grooves 7a formed on its circumferential surface. In this case, the metal foil 3 can be pre-processed into a sleeve profile and, at the latest in step two, fitted onto the shaft member 1 from both axial sides, adjacent to the left and right edges of the lubrication grooves 7a, respectively. Figure 3B In the case shown, the prefabricated profile 3 can be machined into an axial opening with a corresponding lubrication groove 7b, and is assembled onto the shaft member 1 at the latest in step two, ensuring that the opening is aligned with the lubrication groove 7b. This method of forming a cavity or opening on the prefabricated profile avoids the additional process of forming the lubrication groove by machining after forming an anti-friction layer on the surface of the shaft member, which not only reduces material waste but also simplifies the processing steps.

[0032] The method for forming a friction-reducing layer on a shaft member described above, and the shaft member formed using this method, are not limited to specific embodiments. More general technical solutions are defined in the appended claims. Any modifications and improvements to this invention, as long as they comply with the limitations of the appended claims, are within the scope of protection of this invention.

Claims

1. A method for forming a friction-reducing layer (3') on a shaft member (1) of a sliding bearing (10), said shaft member (1) being rotatable relative to a support member (2) of the sliding bearing (10), said friction-reducing layer (3') being formed by metallurgical bonding of a friction-reducing material (3) under hot isostatic pressing conditions on the outer surface of the shaft member (1), at least partially covering the journal position where the shaft member (1) contacts the support member (2), said hot isostatic pressing process comprising the following sequential steps: Step 1) Provide a sleeve (5) such that the sleeve (5) has an internal space consistent with the shape of the integral blank to which the shaft member (1) and the friction-reducing material (3) are intended to be formed; Step 2) Assemble the shaft component (1) and the friction-reducing material (3) in the sleeve (5) according to the shape requirements of the integrated blank; Step 3) After degassing the sleeve (5), seal it so that the residual pressure inside is lower than the predetermined vacuum pressure threshold. Step 4) Hot isostatic pressing is applied to the sleeve (5) containing the shaft member (1) and the friction-reducing material (3) to achieve a metallurgical bond between the friction-reducing material (3) and the shaft member (1); and Step 5) Remove the sleeve (5) and perform subsequent processing on the integrated blank after metallurgical bonding as needed; Its features are: The friction-reducing material (3) is a metal foil made of friction-reducing metal material.

2. The method according to claim 1, characterized in that: The metal foil (3) is copper foil or copper alloy foil, and the shaft member (1) is made of medium-low carbon steel or low alloy steel.

3. The method according to claim 1 or 2, characterized in that: The metal foil (3) is a prefabricated profile whose shape is at least partially adapted to the shaft member (1) at the journal position, and is assembled onto the shaft member (1) at the latest in step two, and can be assembled into the sleeve (5) together with the shaft member (1).

4. The method according to claim 3, characterized in that: The shaft member (1) has lubrication grooves (7a, 7b) extending in the circumferential direction and / or axial direction, and the prefabricated profile (3) has openings or spaces with positions and shapes corresponding to the lubrication grooves (7a, 7b). When assembled onto the shaft member (1), the openings or spaces are set to be aligned with the lubrication grooves (7a, 7b).

5. The method according to claim 4, characterized in that: The lubrication groove (7a) extends in the circumferential direction of the shaft member (1), and the prefabricated profile (3) is constructed in a generally cylindrical shape and is adjacent to the axial edge of the lubrication groove (7a) when assembled onto the shaft member (1).

6. The method according to claim 1 or 2, characterized in that: The thickness of the friction-reducing layer (3') is 0.5 to 2 mm.

7. A shaft member (1) for constituting a sliding bearing (10), configured to rotate relative to a support member (2) of the sliding bearing (10), characterized in that: The shaft member (1) has a friction-reducing layer (3') formed by the method according to any one of claims 1 to 6.

8. A sliding bearing (10) comprising the shaft member (1) as described in claim 7.

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