A finishing mandrel based on improving the roughness of the inner diameter of oil bearing

Abstract

The utility model discloses a kind of whole core rod based on improving the roughness of inner diameter of oil bearing, including core rod main body, including first rod body, expansion rod body and second rod body sequentially arranged along core rod main body axis, expansion rod body includes first connecting portion and second connecting portion, first connecting portion is connected with first rod body, second connecting portion is connected with second rod body, the diameter of expansion rod body is increasing in the direction from first connecting portion to second connecting portion, the outer wall surface of expansion rod body is provided with scraping blade, and multiple scraping blades are arranged in the direction from first connecting portion to second connecting portion.

Description

Technical Field

[0001] This utility model relates to the field of oil-impregnated bearing shaping technology, and in particular to a shaping mandrel based on improving the roughness of the inner diameter of oil-impregnated bearings. Background Technology

[0002] As a crucial mechanical component, the surface roughness of the inner diameter of oil-impregnated bearings directly impacts their performance and lifespan. Current industry standards require that the Ra value of the inner diameter roughness of oil-impregnated bearings be controlled below 0.8. However, in existing forming mold production processes, it is common to encounter the problem of consistently failing to meet the inner diameter roughness standard for oil-impregnated bearings. Traditional forming processes utilize mandrel structures with simple designs and lack effective surface treatment mechanisms, leading to scratches, burrs, and other defects on the bearing's inner wall during the forming process. Furthermore, existing mandrels are prone to adhering to the bearing material during forming, further exacerbating the surface roughness problem. These issues severely affect the product quality and performance stability of oil-impregnated bearings, hindering the production of high-end oil-impregnated bearings. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a shaping mandrel based on improving the roughness of the inner diameter of oil-impregnated bearings, which has the advantages of effectively removing burrs from the inner wall of the bearing, reducing scratch defects, and stably controlling the roughness of the inner diameter.

[0004] A shaping mandrel according to an embodiment of the present invention for improving the roughness of the inner diameter of an oil-impregnated bearing includes: The mandrel body includes a first rod, an expanded rod, and a second rod arranged sequentially along the axis of the mandrel body. The expanded rod includes a first connecting part and a second connecting part. The first connecting part is connected to the first rod, and the second connecting part is connected to the second rod. The diameter of the expanded rod increases from the first connecting part to the second connecting part. The outer wall surface of the expanded rod is provided with scraping blades, and a plurality of scraping blades are arranged along the direction from the first connecting part to the second connecting part.

[0005] A shaping mandrel according to an embodiment of the present invention for improving the inner diameter roughness of an oil-impregnated bearing has at least the following beneficial effects: The shaping mandrel provided in this application achieves progressive shaping through a split mandrel structure. The main body of the mandrel adopts a three-section rod structure. The first rod serves as the introduction reference, the expanding rod achieves progressive expansion of the bearing's inner diameter through a tapered structure with increasing diameter, and the second rod provides the final shaping. The gradient change design of the expanding rod diameter causes progressive plastic deformation of the bearing's inner wall material, avoiding surface tearing caused by one-time diameter expansion. The scraping blades arranged along the axial direction of the expanding rod simultaneously cut the high points of the inner wall during the diameter expansion process, reducing surface roughness through continuous multi-edge cutting action. The connection between the first connecting part and the first rod ensures a smooth transition at the starting end of the expansion, and the cooperation between the second connecting part and the second rod ensures dimensional stability after diameter expansion. The blades are arranged along the expansion direction to form a stepped cutting effect. The preceding blades remove large burrs, and the subsequent blades perform fine finishing, working together to achieve surface roughness control.

[0006] According to an embodiment of the present invention, a shaping mandrel for improving the roughness of the inner diameter of an oil-impregnated bearing has a scraping blade with an annular structure.

[0007] According to an embodiment of the present invention, a shaping mandrel for improving the roughness of the inner diameter of an oil-impregnated bearing is provided with an annular groove, and the edge of the opening of the annular groove is an acute angle to form the scraping blade.

[0008] According to an embodiment of the present invention, a shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing has a plurality of annular grooves arranged at intervals along the direction from the first connecting portion to the second connecting portion.

[0009] According to an embodiment of the present invention, a shaping mandrel for improving the inner diameter roughness of an oil-impregnated bearing is provided with an annular protrusion on the outer circumferential wall of the expanding rod body. The annular protrusion includes a fixing part and a scraping part. The fixing part is fixedly connected to the expanding rod body, and the scraping part is fixedly connected to the fixing part. The end of the scraping part is an acute angle, and the scraping part forms the scraping blade.

[0010] According to an embodiment of the present invention, a shaping mandrel for improving the roughness of the inner diameter of an oil-impregnated bearing is provided, wherein the outer wall of the mandrel body is coated with an anti-stick coating.

[0011] According to an embodiment of the present invention, a shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing is provided with a guide portion at the end of the first rod body away from the expanding rod body.

[0012] According to an embodiment of the present invention, a shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing is provided, wherein the diameter of the first rod body is smaller than the diameter of the expanded rod body.

[0013] According to an embodiment of the present invention, a shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing is provided, wherein the maximum diameter of the expanded rod body is less than or equal to the diameter of the second rod body.

[0014] According to an embodiment of the present invention, a shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing is provided, wherein the first rod body and the second rod body are cylindrical structures.

[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing according to an embodiment of the present invention; Figure 2 for Figure 1 Enlarged view of the marked area; Figure 3 This is a schematic diagram of the second embodiment of the scraping blade of this utility model.

[0017] Explanation of reference numerals in the attached figures: The mandrel body 100; the first rod body 110; the guide part 111; the expanded rod body 120; the annular groove 121; the scraping blade 122; the fixing part 123; the scraping part 124; and the second rod body 130. Detailed Implementation

[0018] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0019] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] In the description of a utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If the terms "first" and "second" are used, they are merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features or the order of the indicated technical features.

[0021] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0022] Reference Figures 1 to 2 This utility model provides a shaping mandrel for improving the inner diameter roughness of an oil-impregnated bearing, comprising a mandrel body 100, wherein a first rod 110, an expanded rod 120, and a second rod 130 are sequentially arranged along the axis of the body. The diameter of the expanded rod 120 increases from the first connecting portion to the second connecting portion, and a plurality of scraping blades 122 are arranged axially on its outer wall surface.

[0023] Understandably, the mandrel body 100 refers to the core component that bears the diameter expansion function. It can be integrally machined from high-strength alloy steel, with functional divisions achieved through a three-section structure. The first rod 110 serves as a guiding reference, its cylindrical structure forming initial positioning with the bearing inner hole. The expanding rod 120 is the functional section that achieves deformation transition, specifically employing a truncated cone structure with a taper angle controlled within the range of 5-15 degrees to ensure gradual material deformation. The scraping blade 122 refers to the cutting edge structure, specifically using carbide inserts or direct machining, with the cutting edge angle maintained at 45-60 degrees to balance cutting force and durability.

[0024] Specifically, when the mandrel is pressed into the bearing's inner bore, the first rod 110 first completes the positioning and guiding. With the advancing action, the tapered surface of the expanding rod 120 gradually expands the bearing's inner diameter, and the diameter gradient causes a progressive plastic flow in the material. During this process, the axially arranged scraping blades 122 sequentially contact the inner wall; the front blade removes large burrs, and the rear blade performs fine finishing. The synergistic effect of the tapered expanding rod 120 and the multi-stage blades ensures precise control of the diameter expansion and simultaneous removal of surface defects. The second rod 130 finally completes the bore diameter shaping, ensuring that the dimensional accuracy meets design requirements.

[0025] Beneficially, this solution achieves stress gradient release through the tapered expanding rod 120, and, combined with the stepped cutting of multi-stage cutting edges, effectively avoids quality defects caused by single deformation. In existing technologies, cutting and diameter expansion are performed in separate steps; in this solution, they are integrated into a simultaneous continuous machining process, enabling the gradual shaping and surface finishing of the oil-impregnated bearing's inner diameter to be completed concurrently. The tapered design of the expanding rod 120 ensures a more uniform distribution of material stress, and the continuous cutting action of the multi-stage cutting edges significantly reduces surface roughness, ensuring that the inner diameter surface quality consistently reaches below Ra0.8. This structure, while guaranteeing machining efficiency, eliminates the risk of dimensional deviations caused by secondary machining in traditional processes.

[0026] Furthermore, such as Figure 1 and Figure 2 As shown, the scraping blade 122 has a ring-shaped structure.

[0027] It is understandable that the annular structure refers to a continuous closed annular cutting edge surrounding the circumference of the expanded rod 120. Specifically, this can be achieved by machining an annular groove on the outer wall of the expanded rod 120 to form a sharp edge. For example, an annular groove can be cut into the surface of the expanded rod 120, so that the edge of the groove opening forms an annular cutting edge. The annular structure allows the cutting force to be evenly distributed along the circumference, avoiding surface scratches caused by localized stress concentration. The annular structure can also be achieved by welding or embedding annular inserts. For example, a carbide annular insert can be fixed to the outer wall of the expanded rod 120 and precision ground to form a continuous cutting edge.

[0028] That is, during the process of pressing the mandrel into the bearing inner hole, the annular cutting edge forms a full circumferential contact with the inner hole surface. As the expanding rod 120 moves along the axis, the annular cutting edge cuts the metal surface. The cutting depth of each annular cutting edge is determined by the diameter gradient of the expanding rod 120, and a stepped cutting area is formed between adjacent annular cutting edges. Through the superposition of multiple annular cutting edges, the microscopic protrusions on the surface are gradually removed. The continuous closing characteristic of the annular cutting edge eliminates the cutting blind zone between traditional point-shaped cutting edges, allowing the metal material to be removed uniformly in the circumferential direction, thereby reducing the anisotropy of surface roughness.

[0029] The advantages are that the annular structure forms a continuous cutting trajectory through full-circumferential contact, eliminating cutting blind spots. Simultaneously, the uniform distribution of the annular cutting edge ensures consistent material removal in the circumferential direction, avoiding pits caused by localized overcutting. This enables uniform cutting of the inner diameter surface of oil-impregnated bearings, eliminating striped machining marks caused by traditional point-shaped cutting edges, effectively controlling the surface roughness of the inner diameter, and meeting the process requirement of Ra≤0.8. The continuous cutting action of the annular cutting edge also reduces the adhesion of metal chips generated during machining, lowering the risk of secondary scratches.

[0030] In some embodiments of this application, such as Figure 2As shown, the expanded rod body 120 is provided with an annular groove 121, and the edge of the opening of the annular groove 121 is acute to form a scraping blade 122.

[0031] It should be noted that, in this application, the annular groove 121 refers to a groove structure that extends continuously along the circumference of the expanded rod 120, and can be formed by machining or electrical discharge machining. Its cross-sectional shape can be V-shaped or U-shaped. The acute angle at the opening of the annular groove 121 refers to the included angle formed at the intersection of the two side walls of the groove, which can be achieved by controlling the angle of the machining tool or by using a secondary fine grinding process. This acute angle structure can form a continuous and uniform cutting edge, producing a precise scraping effect during the expansion process.

[0032] Specifically, during the shaping process of the oil-impregnated bearing, as the expanding rod 120 gradually enters the bearing's inner bore, the sharp-angled edge of the opening of the annular groove 121 contacts the bearing's inner wall. Due to the small thickness of the sharp-angled edge, it can cut into the metal surface and scrape away microscopic protrusions. Multiple annular grooves 121 are arranged at intervals along the axial direction of the expanding rod 120, forming a stepped scraping structure, achieving surface finishing by removing material step by step. The groove depth and spacing can be adjusted according to the hardness of the bearing material; for example, for copper-based powder metallurgy materials, the groove depth can be controlled within the range of 0.05-0.15 mm. The integrated structure of the annular groove 121 avoids the stress concentration problem of traditional welding blades, while the rounded corner design at the bottom of the groove helps to disperse cutting stress.

[0033] Beneficially, the continuous cutting edge formed by the annular groove 121 in this design not only ensures the consistency of the cutting edge geometry but also enhances the support strength of the cutting edge base through the groove structure. Compared to a split cutting edge structure, the integrally formed annular groove 121 avoids the impact of assembly errors on scraping accuracy, while reducing vibration during machining. This enables uniform scraping of the inner wall of the oil-impregnated bearing, effectively removing microscopic surface irregularities and ensuring that the roughness of the machined bearing inner diameter is stably controlled below Ra0.8. The continuous cutting edge structure of the annular groove 121 avoids the vibration marks defects caused by traditional intermittent cutting, and the chip removal space of the groove itself can accommodate metal chips generated during machining, preventing secondary scratches on the machined surface.

[0034] Furthermore, multiple annular grooves 121 are spaced apart along the direction from the first connecting portion to the second connecting portion. During the axial advancement of the expanded rod 120, the spaced annular grooves 121 cause the scraping blades 122 to sequentially contact the inner wall of the oil-impregnated bearing at fixed intervals. Since there is an unprocessed area between the grooves, the cutting action of adjacent grooves will not interfere with each other, thereby avoiding material accumulation or local over-cutting caused by continuous cutting. At the same time, the spaced arrangement creates segmented cutting areas on the surface of the expanded rod 120, generating intermittent scraping during axial movement. Combined with the structure of the expanded rod 120 with increasing diameter, the cutting depth gradually increases with the advancement process, achieving a gradient cutting effect. By using an intermittent arrangement, the cutting action is distributed regularly along the axial direction within the machining area. This ensures a reasonable allocation of machining allowance between adjacent grooves and reduces local thermal stress through intermittent cutting, thereby improving surface machining stability. The scraping blade 122 forms uniformly distributed cutting points on the surface of the expanded rod 120, preventing material tearing or surface unevenness caused by continuous cutting and ensuring consistent scraping amount across all areas of the oil-impregnated bearing's inner diameter. The intermittent arrangement also reduces the accumulation of metal chips during cutting, lowering the risk of secondary scratches and ultimately achieving the technical requirement of consistently controlling the inner diameter roughness Ra value below 0.8.

[0035] Or, in some other embodiments of this application, such as Figure 3 As shown, an annular protrusion is provided on the outer circumference of the expanded rod body 120. The annular protrusion includes a fixing part 123 and a scraping part 124. The fixing part 123 is fixedly connected to the expanded rod body 120, and the scraping part 124 is fixedly connected to the fixing part 123. The end of the scraping part 124 is an acute angle, and the scraping part 124 forms a scraping blade 122.

[0036] In other words, it can be understood that the annular protrusion refers to the raised structure formed around the outer periphery of the expanded rod 120, which can be fixed to the expanded rod 120 by welding or threaded connection, and is used to bear the cutting force of the scraping blade 122. The fixing part 123 refers to the support structure directly connected to the expanded rod 120, which can be a metal base of the same material as the expanded rod 120, and the structural stability is improved by increasing the contact area. The scraping part 124 refers to the cutting structure located at the end of the fixing part 123, which can be made of high-hardness alloy material, machined separately and assembled with the fixing part 123. Its acute angle is formed by grinding process, and it is used to accurately remove burrs and excess material from the inner wall of the bearing.

[0037] Specifically, during the shaping process, when the expanding rod 120 is pushed into the inner bore of the oil-impregnated bearing, the acute angle of the end of the annular protruding scraper portion 124 contacts the inner wall of the bearing. The fixing portion 123 transmits the cutting force to the expanding rod 120, avoiding local stress concentration that could lead to structural deformation. The split design allows the scraper portion 124 to be replaced independently; when the cutting edge wears down, only the scraper portion 124 needs to be replaced without affecting the connection between the fixing portion 123 and the expanding rod 120. When the scraper portion 124 is made of a different material than the fixing portion 123, its wear resistance can be enhanced through heat treatment or coating processes while maintaining the structural strength of the fixing portion 123.

[0038] Beneficially, this solution utilizes a split-type annular protrusion design, allowing for independent adjustment of the cutting edge angle. Simultaneously, the connection between the fixing part 123 and the scraper rod enhances structural rigidity. In existing technologies, the integrally formed cutting edge requires replacement of the entire expanding rod 120 after wear, whereas this solution only requires replacement of the scraping part 124, significantly reducing maintenance costs and achieving precise cutting of the inner wall material of oil-impregnated bearings, effectively controlling the surface roughness of the inner diameter. The independent structural design of the scraping cutting edge 122 improves cutting stability and avoids surface scratches caused by vibration during processing. The split assembly method extends the overall service life of the mandrel while reducing the scrap rate due to localized wear.

[0039] According to some embodiments of this application, the outer wall of the mandrel body 100 is coated with an anti-stick coating. Specifically, the anti-stick coating reduces the chemical affinity between the metal powder and the mandrel surface, thus preventing direct contact between the material and the mandrel during processing. When the expanded rod body 120 extrudes the inner wall of the oil-impregnated bearing, the micron-scale dense structure formed on the coating surface reduces the amount of metal debris retained on the mandrel surface, preventing secondary pressing into the bearing inner wall and causing scratches. Simultaneously, the high-temperature hardness characteristics of the coating maintain a stable cutting clearance between the scraper blade 122 and the bearing inner wall, preventing fluctuations in the cutting depth caused by softening of the mandrel surface. The solution introduces a functional coating to create a dynamic isolation layer at the interface between the mandrel and the bearing. This eliminates adhesive wear caused by direct metal-to-metal contact and avoids the instability of cutting force caused by simply reducing the surface roughness of the mandrel. It effectively controls the surface integrity of the inner wall of the oil-impregnated bearing during the shaping process, prevents micro-pit defects caused by metal chips being pressed in, ensures that the inner diameter roughness consistently meets the process requirement of Ra≤0.8, and extends the service life of the mandrel under continuous machining conditions.

[0040] According to some embodiments of this application, a guide portion 111 is provided at the end of the first rod 110 away from the expanded rod 120.

[0041] It is understood that the guide section 111 refers to a guide structure located at the front end of the mandrel body 100 to guide the mandrel into the inner hole of the oil-impregnated bearing. Specifically, it can be implemented using a conical or frustum-shaped geometric structure, with its diameter gradually increasing along the insertion direction to form a progressive contact with the bearing inner hole. During the initial insertion stage of the mandrel, this structure guides the mandrel axis to automatically align with the bearing inner hole axis through the geometric guidance effect.

[0042] That is, when the mandrel moves along the inner bore of the oil-impregnated bearing, the guide portion 111 first contacts the edge of the bearing inner bore. Since the diameter of the front end of the guide portion 111 is smaller than the diameter of the bearing inner bore, its conical or inclined surface generates a radial force during the contact process, pushing the mandrel to adjust its position along the axis of the inner bore. As the mandrel continues to advance, the diameter of the guide portion 111 gradually increases until it matches the diameter of the inner bore. At this point, the axis of the mandrel and the axis of the bearing inner bore are completely coincident, ensuring that the scraping blade 122 on the subsequent expansion rod 120 makes uniform contact with the inner bore surface. This axial guiding mechanism eliminates the centering deviation caused by manual operation or mechanical clamping, and avoids excessive cutting on one side of the scraping blade 122 due to mandrel tilting, which would cause surface scratches.

[0043] Beneficially, this solution achieves automatic centering through geometric guidance, ensuring the coaxiality of the mandrel and the bearing inner hole without the need for additional positioning devices. This fundamentally avoids surface roughness deterioration caused by centering errors and effectively solves the problem of excessive inner diameter surface roughness due to centering deviation during mandrel insertion. The self-centering function achieved through geometric guidance ensures that the scraping blade 122 makes uniform contact with the bearing inner wall, eliminating scratches and burrs caused by abnormal friction, and significantly improving the surface quality stability of the inner diameter shaping of oil-impregnated bearings.

[0044] According to some embodiments of this application, the diameter of the first rod 110 is smaller than the diameter of the expanded rod 120. Meanwhile, the maximum diameter of the expanded rod 120 is less than or equal to the diameter of the second rod 130.

[0045] That is, the smaller diameter of the first rod 110 reduces the initial contact area with the inner wall when entering the inner bore of the oil-impregnated bearing, thereby reducing insertion resistance. As the diameter of the expanded rod 120 increases, its outer wall applies radial pressure to the inner wall of the bearing during axial movement, causing the metal powder to undergo gradual plastic deformation. Because the diameter change is gradual rather than abrupt, the internal stress distribution of the material is more uniform, avoiding surface cracks or burrs caused by localized stress concentration. For example, the diameter of the first rod 110 can be 0.1 mm to 0.5 mm smaller than that of the expanded rod 120, thus forming a gentle transition zone during the diameter expansion process, promoting the densification of the metal powder and forming a smooth surface. After the expanded rod 120 completes the initial scraping of the bearing's inner wall, the second rod 130 enters the inner diameter region with a larger diameter. Since the end diameter of the expanded rod 120 is less than or equal to the starting diameter of the second rod 130, when the second rod 130 moves along the axial direction, its outer wall applies radial pressure to the inner wall of the bearing, flattening any microscopic protrusions remaining during the expansion process. The stepped transition structure allows the material to deform in stages during the forming process, avoiding excessive deformation in a single step that could lead to surface tearing. Simultaneously, the gap between the cylindrical surface of the second rod 130 and the end of the expanding section can accommodate scraped debris, preventing it from being squeezed onto the machined surface during the forming process.

[0046] Beneficially, the stepped diameter difference design between the first rod 110 and the expanded rod 120 allows the expansion process to proceed in stages, resulting in more uniform material deformation and effective control of surface roughness. This reduces frictional resistance during mandrel insertion, prevents surface defects caused by stress concentration, and promotes uniform densification of the metal powder through progressive diameter expansion, ultimately achieving the technical requirement of Ra≤0.8 for the inner diameter roughness of the oil-impregnated bearing. Furthermore, the transition between the expanded rod 120 and the second rod 130 effectively solves the material tearing problem caused by abrupt diameter changes during the transition, eliminating the need for secondary pressing of surface residues during the shaping process. The bearing inner wall achieves a smooth connection between the expansion and shaping processes, with microscopic protrusions on the surface gradually eliminated by the stepped shaping structure, ensuring that the inner diameter roughness is controlled within the technical requirement of Ra≤0.8.

[0047] According to some embodiments of this application, the first rod 110 and the second rod 130 are cylindrical structures.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A shaping mandrel for improving the inner diameter roughness of oil-impregnated bearings, characterized in that, include: The mandrel body includes a first rod, an expanded rod, and a second rod arranged sequentially along the axis of the mandrel body. The expanded rod includes a first connecting part and a second connecting part. The first connecting part is connected to the first rod, and the second connecting part is connected to the second rod. The diameter of the expanded rod increases from the first connecting part to the second connecting part. The outer wall surface of the expanded rod is provided with scraping blades, and a plurality of scraping blades are arranged along the direction from the first connecting part to the second connecting part.

2. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 1, characterized in that, The scraping blade has a ring-shaped structure.

3. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 2, characterized in that, The expanded rod body is provided with an annular groove, and the edge of the opening of the annular groove is acute to form the scraping blade.

4. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 3, characterized in that, The plurality of the annular grooves are arranged at intervals along the direction from the first connecting portion to the second connecting portion.

5. A shaping mandrel based on improving the roughness of the inner diameter of an oil-impregnated bearing according to claim 3, characterized in that, The outer circumferential wall of the expanded rod is provided with an annular protrusion. The annular protrusion includes a fixing part and a scraping part. The fixing part is fixedly connected to the expanded rod, and the scraping part is fixedly connected to the fixing part. The end of the scraping part is an acute angle, and the scraping part forms the scraping blade.

6. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 1, characterized in that, The outer wall of the mandrel body is coated with an anti-stick coating.

7. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 1, characterized in that, A guide portion is provided at the end of the first rod that is away from the expanded rod.

8. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 1, characterized in that, The diameter of the first rod is smaller than the diameter of the expanded rod.

9. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 8, characterized in that, The maximum diameter of the expanded rod is less than or equal to the diameter of the second rod.

10. A shaping mandrel based on improving the inner diameter roughness of an oil-impregnated bearing according to claim 9, characterized in that, The first rod and the second rod are cylindrical structures.

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