External spline bushing with positioning table and machining method

Abstract

The invention belongs to the technical field of machining, and particularly relates to an external spline bushing with a positioning table and a machining method.The machining method comprises the steps that the external spline bushing with the positioning table is designed into a spline shaft and a bushing base in a split mode, the spline shaft and the bushing base are machined to preset sizes respectively, and grooves are formed in the spline shaft and the bushing base respectively; an anti-rotation pin is bonded in a groove of the lower end shaft of the spline shaft; the lower end face of the lining base is heated; and in the hot state of the lining base, the spline shaft bonded with the anti-rotating pin is pressed into an inner hole of the lining base in the axial direction, after the assembled spline shaft and the lining base are cooled, glue is used for bonding at the joint, and the external spline lining with the positioning table is obtained. Through comprehensive application of the split design and the hot pressing process, the external spline can be precisely machined through a dressing grinding wheel by using a tooth grinding process, the tooth profile is detected by using a conventional metering method, and a special gauge does not need to be manufactured. The technical problems that in the prior art, the manufacturing cost is too high, the period is too long, and tooth grinding process molded surface interference exists are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and in particular relates to an external spline bushing with a positioning platform and a processing method thereof. Background Art

[0002] The spline bushing described in this application ( Figure 1 )It is made of 30CrMnSiA material with a hardness of HRC 35-40, and is used to connect the spline surface of the target product and the related parts of the fixture. It bears a certain torsion force during operation. The bushing is a thin-walled structure as a whole, with a non-through triangular tooth external spline at the upper end and a cylindrical stop boss with a diameter larger than the spline surface at the lower end. The inner hole at the upper end of the bushing is a round hole, and the inner hole at the lower end is a square hole. The spline has a coaxial accuracy requirement relative to the outer circle and square hole at the lower end. The difficulty and focus of processing this type of parts lies in its spline surface.

[0003] For spline tooth surface bushings with medium and low hardness, the more common technical solution is integral manufacturing, in which the spline tooth shape is processed by the gear shaping process. However, when using the gear shaping process, special gear shaping tools and special tooling such as spline ring gauges and proofreading gauges for inspection are required. There are disadvantages such as excessively high manufacturing costs and a long development cycle for supporting tooling. Especially in single-piece and small-batch production, the tooling manufacturing cost and cycle are much greater than the product itself. Some precision spline surfaces are also processed by the gear grinding process. When the gear grinding process is used, the parts need to meet the minimum diameter size of the spline surface that is larger than the maximum outer circle size of the other surfaces, or a blank tool of sufficient size is reserved at the connection between the spline surface and another surface to avoid interference problems during spline grinding.

[0004] The document with publication number CN 107641684A discloses a method for processing spline bushings including gear shaping, and the third step "finely machining and splining the annealed workpiece" describes the processing method of the spline tooth surface; the document with publication number CN103447774A discloses a method for extruding splines (see the third step); the document with publication number CN107984169A discloses a process method for processing splines using a mold. The above technologies have solved the processing quality and efficiency problems of spline bushing parts to varying degrees, but none of them have solved the cycle and cost problems of developing special tooling or the grinding interference problem, and their reference role for the application is limited. In order to solve the problems of high manufacturing cost and long cycle of such parts using gear shaping technology and surface interference of grinding technology, a new process method needs to be proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for processing an external spline bushing with a positioning platform, so as to solve the technical problems of high manufacturing cost, long cycle and surface interference of the gear grinding process in the prior art of processing an external spline bushing with a positioning platform using a gear shaping process.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The first invention is a method for processing an external spline bushing with a positioning table, comprising the following steps: S1: The corresponding workpieces to be processed of the spline shaft and the bushing base are respectively processed to preset sizes, and grooves are respectively opened in the lower end shaft of the spline shaft and the inner hole of the bushing base; S2: bonding the anti-rotation pin in the groove of the lower end shaft of the spline shaft; and heating the lower end surface of the bushing base; S3: When the bushing base is in a hot state, the spline shaft with the anti-rotation pin bonded thereto is pressed axially into the inner hole of the bushing base, wherein the anti-rotation pin on the spline shaft is matched with the groove of the bushing base; S4: After the assembled spline shaft and bushing base are cooled, glue is used to bond them at the joint to obtain an external spline bushing with a positioning table.

[0007] Preferably, the spline shaft comprises: a spline profile, an empty blade segment and an assembly shaft; the spline profile, the empty blade segment and the assembly shaft are arranged in sequence from top to bottom, and the assembly shaft is connected to a bushing base.

[0008] Preferably, the bushing base has a stepped outer circle and three sections of inner holes, wherein the first inner hole is used to cooperate with the spline shaft, the second inner hole is a hollow hole, and the square hole is a square hole; the first inner hole, the second inner hole and the square hole are arranged in sequence from top to bottom.

[0009] Preferably, the cylindricity and coaxiality of the first inner hole and the second inner hole of the bushing base with the outer circle of the step are not greater than 0.01 mm.

[0010] Preferably, the spline shaft comprises: a spline profile, an empty blade segment and an assembly shaft, and S1 specifically comprises: S101: Turn the spline shaft and bushing base to a preset outer diameter, machine a center hole on both end faces of the spline shaft, and machine a threading hole on the square hole of the bushing base, and then perform quenching and aging heat treatment; S102: grinding the first inner hole and the second inner hole and the outer circle of the bushing base to a specified size, and then performing wire cutting on the square hole based on the ground outer circle, with the coaxiality being no greater than 0.01 mm; S103: grinding the spline profile of the spline shaft to a specified size, and grinding the assembly shaft of the spline shaft to have an interference fit with the first inner hole of the bushing base; then grinding the outer cylindrical end surface and cleaning the root; S104: Grooves are respectively machined on the outer wall of the assembly shaft of the spline shaft and the inner wall of the first inner hole of the bushing base.

[0011] Preferably, the spline shaft and the bushing base are interference fit, and the interference is no more than 0.005 mm.

[0012] Preferably, in S2, the heating temperature is 500-550° C., and the heating time is 4-5 min.

[0013] Preferably, the groove depth in S1 is 0.1-0.2 mm.

[0014] Preferably, the size of the anti-rotation pin in S2 is adapted to the groove, so that the groove can completely contain the largest entity of the anti-rotation pin.

[0015] The second invention is an external spline bushing with a positioning platform, which is made by using any of the processing methods described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1) Thanks to the improved structure and the comprehensive application of hot pressing process, the triangular external spline can be precisely processed by dressing the grinding wheel and using the gear grinding process to obtain high processing accuracy; the tooth shape can be detected by general optical metrology methods without the need to manufacture special gauges. The grinding wheel can continue to be used after dressing, and the overall manufacturing cost of this method is much lower than the development cost of the gear shaping cutter required for gear shaping.

[0017] 2) The manufacturing cycle is greatly shortened due to the reduction of the development process of special tooling.

[0018] 3) Hot assembly process is often used in CNC machine tool handle installation or mold manufacturing. The technical solution of combining this technology with cold processes such as gear grinding for precision fixtures is rarely reported. The technical solution described in this application uses an anti-rotation pin combined with hot pressing and gluing processes to make the spline bushing firmly connected and reliable to use, and can transmit the torque required by the design.

[0019] 4) The heating temperature of the bushing base is 500~550℃. When the heating temperature is lower than 500 degrees Celsius, the bushing size expands too small, the axle pin fitting pressure is large, and the fracturing scrap rate reaches 30%; when the bushing heating temperature is higher than 550 degrees Celsius, it exceeds the tempering temperature of the 30CrMnSiA material, and the bushing crack rate after fitting reaches 20%. The temperature used in this application is sufficient to ensure the application of hot assembly process in thin-walled parts. By combining hot assembly technology with anti-rotation pins, the bushing is firmly combined and has the torsion resistance that meets the use requirements without causing the thin-wall cracking problem that is prone to occur in cold assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the structure of the external spline bushing in the prior art; Figure 2 It is a schematic diagram of the structure of the spline shaft of the present invention; Figure 3 It is a schematic diagram of the bushing base structure of the present invention; Figure 4 Schematic diagram of the groove structure of the present invention; wherein (a) is a cross-sectional view of the assembly shaft; (b) is a cross-sectional view of the AA surface of the bushing base; Figure 5 It is a schematic diagram of the structure of the external spline bushing with a positioning platform of the present invention.

[0022] Among them: 1-spline shaft; 101-spline profile; 102-empty blade segment; 103-assembly shaft; 2-bushing base; 201-step outer circle; 202-first inner hole; 203-second inner hole; 204-square hole; A-glue bonding point; 3-external spline bushing with positioning platform. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0026] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0027] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings: In order to solve the problems of manufacturing cost, cycle and interference caused by the existing technical solutions, this application proposes a processing technology with hot assembly as the core technology. The first of these solutions is to split the bushing into a split structure that does not interfere with each other according to the structural characteristics of the parts; the second is to use hot assembly technology combined with anti-rotation pins to ensure that the bushing is firmly combined and has the torsion resistance that meets the use requirements without causing the problem of thin-wall cracking that is easily caused by cold assembly. Furthermore, this application requires the hot assembly process parameters of the bushing suitable for 30CrMnSiA material, and the specific contents are as follows: See also Figure 5 The present application discloses a method for processing an external spline bushing with a positioning platform, comprising the following steps: S1: The corresponding workpieces to be processed of the spline shaft 1 and the bushing base 2 are respectively processed to preset sizes, and grooves are respectively opened in the lower end shaft of the spline shaft 1 and the inner hole of the bushing base 2; S2: bonding the anti-rotation pin in the groove of the lower end shaft of the spline shaft 1; and heating the lower end surface of the bushing base 2; S3: When the bushing base 2 is in a hot state, the spline shaft 1 bonded with the anti-rotation pin is pressed into the inner hole of the bushing base 2 along the axial direction, wherein the anti-rotation pin on the spline shaft 1 is matched with the groove of the bushing base 2; S4: After the assembled spline shaft 1 and bushing base 2 are cooled, glue is used to bond them at the joint to obtain an external spline bushing with a positioning platform.

[0030] This application innovatively splits the external spline bushing with positioning table into a spline shaft 1 and a bushing base 2, adopts a split structure to avoid grinding interference, and adopts a grinding process to avoid the development of special tools, measuring tools, etc., which solves the technical problem of high manufacturing cost. The hot assembly (hot pressing) process is used to avoid the damage of cold assembly to the thin-walled part of the bushing, which is mainly reflected in cracks visible to the naked eye or micro cracks invisible to the naked eye. At the same time, the anti-rotation pin is used to enable the bushing to bear torque, so that the spline bushing is firmly connected and reliable to use, and can transmit the torque required by the design; in summary, this application benefits from the improved structure and the comprehensive application of hot pressing process. The triangular external spline can be precisely processed by the grinding process through the dressing of the grinding wheel to obtain high processing accuracy; the tooth shape can be detected by general optical metrology methods without the need to manufacture special gauges. The grinding wheel can continue to be used after dressing, and the overall manufacturing cost of this method is much lower than the development cost of the gear shaping cutter required for gear shaping.

[0031] In some embodiments, see Figure 2 The spline shaft 1 includes: a spline profile 101, an empty blade segment 102 and an assembly shaft 103; the spline profile 101, the empty blade segment 102 and the assembly shaft 103 are arranged in sequence from top to bottom, and the assembly shaft 103 is connected to the bushing base 2. The spline profile 101 of the split-designed spline shaft 1 is precisely machined by a gear grinding process to obtain high machining accuracy without affecting the positioning table. The machined spline profile 101 can be inspected by a general optical metrology method for tooth shape without the need to manufacture a special gauge.

[0032] In some embodiments, see Figure 3 The bushing base 2 has a stepped outer circle 201 and three inner holes, wherein the first inner hole 202 is used to cooperate with the spline shaft 1, the second inner hole 203 is a hollow cutter, and the square hole 204 is a square hole; the first inner hole 202, the second inner hole 203 and the square hole 204 are arranged in sequence from top to bottom. The assembly shaft 103 is interference fitted with the first inner hole 202, and the interference is not greater than 0.005mm.

[0033] In some embodiments, the cylindricity and coaxiality of the first inner hole 202 and the second inner hole 203 of the bushing base 2 and the step outer circle 201 are no greater than 0.01 mm.

[0034] In some embodiments, the spline shaft 1 includes: a spline profile 101, an empty blade segment 102 and an assembly shaft 103, and the S1 specifically includes: S101: turning the spline shaft 1 and the bushing base 2 to a preset outer diameter, machining a center hole at both end faces of the spline shaft 1, machining a threading hole at the square hole 204 of the bushing base 2, and then performing quenching and aging heat treatment; S102: Grind the first inner hole 202 and the second inner hole 203 and the outer circle of the bushing base 2 to a specified size, and then perform wire cutting on the square hole 204 based on the ground outer circle, with the coaxiality being no greater than 0.01 mm; S103: grinding the spline profile 101 of the spline shaft 1 to a specified size, and grinding the assembly shaft 103 of the spline shaft 1 to an interference fit with the first inner hole 202 of the bushing base 2; then grinding the outer cylindrical end surface and cleaning the root; S104: grooves are machined on the outer wall of the assembly shaft 103 of the spline shaft 1 and the inner wall of the first inner hole 202 of the bushing base 2 respectively.

[0035] In some embodiments, in S2, the heating temperature is 500~550℃, and the heating time is 4~5min. Hot assembly process is often seen in the installation of CNC machine tool handles or the manufacture of mold products. The technical solution of combining this technology with cold processes such as gear grinding for use in precision fixtures is rarely reported. The technical solution described in this application adopts an anti-rotation pin and combines hot pressing process and adhesive process to make the spline bushing firmly connected and reliable to use. It can transmit the torque required by the design, and the heating temperature of the bushing base is 500~550℃. When the heating temperature is lower than 500 degrees Celsius, the bushing size expands too small, the shaft pin matching pressure is large, and the fracturing scrap rate reaches 30%; when the bushing heating temperature is higher than 550 degrees Celsius, it exceeds the tempering temperature of 30CrMnSiA material, and the bushing crack rate after matching reaches 20%. The temperature used in this application is sufficient to ensure the application of hot assembly process in thin-walled parts.

[0036] In some embodiments, the groove depth in S1 is 0.1-0.2 mm.

[0037] In some embodiments, the size of the anti-rotation pin in S2 is adapted to the groove, so that the groove can completely contain the largest entity of the anti-rotation pin. The anti-rotation pin is combined with the hot assembly technology, so that the bushing is firmly combined and has the torsion resistance that meets the use requirements without causing the thin wall cracking problem that is easy to occur in cold assembly.

[0038] [Example 1] 1) Redesign the part to Figure 2 The split structure shown in the figure. The upper end of the spline shaft 1 is the general spline profile 101, the middle is the empty knife segment 102, and the lower end is the assembly shaft 103; the bushing base 2 has a stepped outer circle 201 and three sections of inner holes, wherein the first inner hole 202 is used to cooperate with the spline shaft 1, the second inner hole 203 is an empty knife, and the lower end is a square hole 204.

[0039] 2) The workpieces to be processed of the spline shaft 1 and the bushing base 2 are turned to the specified size, the center holes are processed on the two end faces of the spline shaft 1, and the threading holes are processed at the square hole 204 of the bushing base 2. Subsequently, quenching and aging heat treatment are performed.

[0040] 3) Grind the first inner hole 202 and the stepped outer circle 201 of the bushing base 2 to the specified size, ensuring that the cylindricity and coaxiality are not greater than 0.01 mm, and then perform wire cutting on the square hole 204 based on the ground stepped outer circle 201 to ensure the size and coaxiality.

[0041] 4) Grind the spline profile 101 of the spline shaft 1 to the specified size, and grind the assembly shaft 103 at the lower end of the spline shaft 1 to have an interference fit with the first inner hole 202 of the bushing base 2, with the interference amount not exceeding 0.005mm; then grind the outer cylindrical end face and clean the root.

[0042] 5) Grooves are machined on the assembly shaft 103 of the spline shaft 1 and the first inner hole 202 of the bushing base 2, respectively, wherein the groove depth is 0.1 mm, and the assembly shaft 103 is a Ra0.4 shaft, see Figure 4 .

[0043] 6) Use glue to firmly bond the anti-rotation pin to the R0.5 groove of the spline shaft 1, and clean up the excess glue. The anti-rotation pin is a cylindrical pin.

[0044] 7) Use a heating platform to heat the lower end surface of the bushing base 2 at a temperature of 500°C for 5 minutes.

[0045] 8) When the bushing base 2 is hot, slowly press the spline shaft 1 with the cylindrical pin attached into the inner hole of the bushing base 2 along the axial direction, and align the protruding cylindrical pin of the spline shaft 1 with the groove of the bushing base 2.

[0046] 9) After the spline shaft 1 and the bushing base 2 have cooled, use glue to bond the spline shaft 1 and the bushing base 2 together. Figure 5 .

[0047] [Example 2] 1) Redesign the part to Figure 5 The split structure shown in FIG. Figure 2 The upper end of the spline shaft 1 is the general spline profile 101, the middle is the empty blade segment 102, and the lower end is the assembly shaft 103; see Figure 3 The bushing base 2 has a stepped outer circle 201 and three inner holes, wherein the first inner hole 202 is used to cooperate with the spline shaft 1, the second inner hole 203 is a hollow hole, and the lower end is a square hole 204.

[0048] 2) The workpieces to be processed of the spline shaft 1 and the bushing base 2 are turned to the specified size, the center holes are processed on the two end faces of the spline shaft 1, and the threading holes are processed at the square hole 204 of the bushing base 2. Subsequently, quenching and aging heat treatment are performed.

[0049] 3) Grind the first inner hole 202 and the stepped outer circle 201 of the bushing base 2 to the specified size, ensuring that the cylindricity and coaxiality are not greater than 0.01 mm, and then perform wire cutting on the square hole 204 based on the ground stepped outer circle 201 to ensure the size and coaxiality.

[0050] 4) Grind the spline profile 101 of the spline shaft 1 to the specified size, and grind the assembly shaft 103 at the lower end of the spline shaft 1 to have an interference fit with the first inner hole 202 of the bushing base 2, with the interference amount not exceeding 0.005mm; then grind the outer cylindrical end face and clean the root.

[0051] 5) A groove is machined on the assembly shaft 103 of the spline shaft 1 and the first inner hole 202 of the bushing base 2, wherein the groove depth is 0.2 mm. Figure 4 .

[0052] 6) Use glue to firmly bond the anti-rotation pin to the R0.5 groove of the spline shaft 1, and clean up the excess glue. The anti-rotation pin is a cylindrical pin.

[0053] 7) Use a heating platform to heat the lower end surface of the bushing base 2 at a temperature of 550°C for 4 minutes.

[0054] 8) When the bushing base 2 is hot, slowly press the spline shaft 1 with the cylindrical pin attached into the inner hole of the bushing base 2 along the axial direction, and align the protruding cylindrical pin of the spline shaft 1 with the groove of the bushing base 2.

[0055] 9) After the spline shaft 1 and the bushing base 2 have cooled, use glue to bond the spline shaft 1 and the bushing base 2 together. Figure 5 .

[0056] [Example 3] 1) Redesign the part to Figure 5 The split structure shown in FIG. Figure 2 The upper end of the spline shaft 1 is the general spline profile 101, the middle is the empty blade segment 102, and the lower end is the assembly shaft 103; see Figure 3 The bushing base 2 has a stepped outer circle 201 and three inner holes, wherein the first inner hole 202 is used to cooperate with the spline shaft 1, the second inner hole 203 is a hollow hole, and the lower end is a square hole 204.

[0057] 2) The workpieces to be processed of the spline shaft 1 and the bushing base 2 are turned to the specified size, the center holes are processed on the two end faces of the spline shaft 1, and the threading holes are processed at the square hole 204 of the bushing base 2. Subsequently, quenching and aging heat treatment are performed.

[0058] 3) Grind the first inner hole 202 and the stepped outer circle 201 of the bushing base 2 to the specified size, ensuring that the cylindricity and coaxiality are not greater than 0.01 mm, and then perform wire cutting on the square hole 204 based on the ground stepped outer circle 201 to ensure the size and coaxiality.

[0059] 4) Grind the spline profile 101 of the spline shaft 1 to the specified size, and grind the assembly shaft 103 at the lower end of the spline shaft 1 to have an interference fit with the first inner hole 202 of the bushing base 2, with the interference amount not exceeding 0.005mm; then grind the outer cylindrical end face and clean the root.

[0060] 5) A groove is machined on the assembly shaft 103 of the spline shaft 1 and the first inner hole 202 of the bushing base 2, wherein the groove depth is 0.2 mm. Figure 4 .

[0061] 6) Use glue to firmly bond the anti-rotation pin to the R0.5 groove of the spline shaft 1, and clean up the excess glue. The anti-rotation pin is a cylindrical pin.

[0062] 7) Use a heating platform to heat the lower end surface of the bushing base 2 at a temperature of 520°C for 5 minutes.

[0063] 8) When the bushing base 2 is hot, slowly press the spline shaft 1 with the cylindrical pin attached into the inner hole of the bushing base 2 along the axial direction, and align the protruding cylindrical pin of the spline shaft 1 with the groove of the bushing base 2.

[0064] 9) After the spline shaft 1 and the bushing base 2 have cooled, use glue to bond the spline shaft 1 and the bushing base 2 together. Figure 5 .

[0065] In particular, the chamfers not marked in the figure are processed according to C0.5.

[0066] The split structure is used to avoid grinding interference, and the difficulty lies in the structural segmentation. This application innovatively splits the design of the external spline bushing with a positioning table into a spline shaft 1 and a bushing base 2. The spline shaft 1 adopts a grinding process to avoid the development of special tools, measuring tools, etc. The spline shaft 1 and the bushing base 2 are assembled using a hot assembly (hot pressing) process to avoid damage to the thin-walled part of the bushing caused by cold assembly (mainly manifested in cracks visible to the naked eye or micro cracks invisible to the naked eye). The difficulty lies in the control of heating temperature and time, and pay attention to slow axial pressing. The anti-rotation pin is used in combination with hot pressing and gluing processes, so that the spline bushing is firmly connected and reliable in use, and can transmit the torque required by the design. The heating temperature of the bushing base is 500~550℃. When the heating temperature is lower than 500 degrees Celsius, the bushing size expands too small, the shaft pin matching pressure is large, and the fracturing scrap rate reaches 30%; when the bushing heating temperature is higher than 550 degrees Celsius, it exceeds the tempering temperature of the 30CrMnSiA material, and the bushing crack rate after matching and pressing reaches 20%. The temperature used in this application is sufficient to ensure the application of hot assembly technology in thin-walled parts.

[0067] The present application also discloses an external spline bushing with a positioning platform manufactured by any of the above methods.

[0068] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for processing an external spline bushing with a positioning table, characterized in that: The following steps are involved: S1: processing the corresponding workpieces to be processed of the spline shaft (1) and the bushing base (2) to preset sizes, and respectively opening grooves in the lower end shaft of the spline shaft (1) and the inner hole of the bushing base (2); S2: bonding an anti-rotation pin into a groove of the lower end shaft of the spline shaft (1); and heating the lower end surface of the bushing base (2); S3: When the bushing base (2) is in a hot state, the spline shaft (1) bonded with an anti-rotation pin is pressed axially into the inner hole of the bushing base (2), wherein the anti-rotation pin on the spline shaft (1) is matched with the groove of the bushing base (2); S4: After the assembled spline shaft (1) and bushing base (2) have cooled, glue is used to bond them together at the joint to obtain an external spline bushing with a positioning platform.

2. A method for processing an external spline bushing with a positioning platform according to claim 1, characterized in that: The spline shaft (1) comprises: a spline profile (101), an empty blade segment (102) and an assembly shaft (103); the spline profile (101), the empty blade segment (102) and the assembly shaft (103) are arranged in sequence from top to bottom, and the assembly shaft (103) is connected to a bushing base (2).

3. The method for processing an external spline bushing with a positioning platform according to claim 1, characterized in that: The bushing base (2) has a stepped outer circle (201) and three sections of inner holes, wherein the first inner hole (202) is used to cooperate with the spline shaft (1), the second inner hole (203) is a hollow hole, and the square hole (204) is a square hole; the first inner hole (202), the second inner hole (203) and the square hole (204) are arranged in sequence from top to bottom.

4. A method for processing an external spline bushing with a positioning platform according to claim 3, characterized in that: The cylindricity and coaxiality of the first inner hole (202) and the second inner hole (203) of the bushing base (2) and the step outer circle (201) are not greater than 0.01 mm.

5. The method for processing an external spline bushing with a positioning platform according to claim 3, characterized in that: The spline shaft (1) comprises: a spline profile (101), an empty blade segment (102) and an assembly shaft (103), and S1 specifically comprises: S101: turning the spline shaft (1) and the bushing base (2) to a preset outer diameter, machining a center hole at both end faces of the spline shaft (1), machining a threading hole at the square hole (204) of the bushing base (2), and then performing quenching and aging heat treatment; S102: grinding the first inner hole (202) and the second inner hole (203) and the outer circle of the bushing base (2) to a specified size, and then performing wire cutting on the square hole (204) based on the ground outer circle, with the coaxiality being no greater than 0.01 mm; S103: grinding the spline profile (101) of the spline shaft (1) to a specified size, and grinding the assembly shaft (103) of the spline shaft (1) to an interference fit with the first inner hole (202) of the bushing base (2); then grinding the outer cylindrical end surface and cleaning the root; S104: Grooves are respectively machined on the outer wall of the assembly shaft (103) of the spline shaft (1) and the inner wall of the first inner hole (202) of the bushing base (2).

6. The method for processing an external spline bushing with a positioning platform according to claim 1, characterized in that: The spline shaft (1) and the bushing base (2) are interference fit, and the interference amount is no greater than 0.005 mm.

7. A method for processing an external spline bushing with a positioning platform according to claim 1, characterized in that: In S2, the heating temperature is 500-550° C., and the heating time is 4-5 min.

8. The method for processing an external spline bushing with a positioning platform according to claim 1, characterized in that: The groove depth in S1 is 0.1-0.2 mm.

9. A method for processing an external spline bushing with a positioning platform according to claim 8, characterized in that: The size of the anti-rotation pin in S2 is adapted to the groove, so that the groove can completely contain the largest entity of the anti-rotation pin.

10. An external spline bushing with a positioning platform, characterized in that: The method is prepared by the processing method described in any one of claims 1 to 9.

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