A processing method for rounding internal and external spline surfaces

Abstract

The present invention discloses a processing method that can be used for chamfering internal and external spline surfaces, comprising the following steps: S1, adopting a one-clamp-one-support or direct clamping clamping method, and clamping by designing an elastic bushing or a spline bushing; S2, aligning the external spline by designing a spline locating ring, and processing by a divided-step method; S3, designing a spline bushing based on the same principle as in step S2, and aligning the internal spline; S4, designing a forming column milling cutter; S5, constructing a two-dimensional or three-dimensional spline model of corresponding size; the method of the present invention has high processing quality and can effectively improve the reliability and stability of the spline connection.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical processing, and in particular to a processing method that can be used for rounding internal and external spline surfaces. Background Art

[0002] Splines include internal splines and external splines. Spline connection is a common mechanical connection method. In the design of splines, the fillet treatment of the spline surface can effectively reduce stress concentration and improve the fatigue strength and fracture resistance of the parts; on the other hand, the fillet treatment of the spline surface increases the storage space of the spline lubricant, making it easier for the lubricant to enter the spline contact surface to form a uniform oil film, reducing the friction and wear of the spline; in addition, the fillet treatment of the spline surface can effectively avoid the sharp edges and corners of the spline from being damaged and scratched during the operation of the spline.

[0003] However, in actual engineering applications, due to the complexity of the spline surface and the difficulty in tool design and program compilation, manual chamfering and rounding are often used by fitters, making it difficult for the spline surface rounding dimensions to meet design requirements and poor dimensional consistency. There is an urgent need for a high-precision and efficient CNC rounding processing technology for spline surfaces.

[0004] Patent publication number CN214350631U discloses an external spline fillet rolling tool, comprising a stud bolt and a body, wherein the stud bolt is located inside the body, a sleeve is provided at one end of the stud bolt, the stud bolt and the sleeve are threadedly connected, a spring, a washer, and a nut are sequentially provided on the top of the sleeve, and the nut is threadedly connected to the body, an opening is provided on the outer surface of the body, a scale is provided on the outer surface of the body corresponding to the opening, a first screw is provided between the scale disk and the body, and a scale is provided on the outer surface of the scale disk. In this utility model, a dedicated rolling tool is designed, and after each part is clamped, all spline fillets are continuously rolled on a lathe. The external spline fillet rolling tool disclosed in this patent has high manufacturing costs, the processing quality of the spline surface fillet depends on the quality of the tool, and it is impossible to perform fillet processing on the internal spline surface. Summary of the Invention

[0005] The present invention is mainly aimed at the existing technology, in which due to the complexity of the spline surface and the difficulty of tool design and program compilation, manual chamfering and then rounding are mostly adopted by fitters, which makes it difficult for the rounding size of the spline surface to meet the design requirements and the dimensional consistency is poor. A processing method that can be used for rounding the internal and external spline surfaces is provided.

[0006] In view of the above technical problems, the technical solutions of the present invention are as follows:

[0007] A processing method for rounding the internal and external spline surfaces includes the following steps:

[0008] S1. Chamfer the spline surface on a CNC machining center using a clamping and supporting or direct clamping method. Design elastic bushings or spline bushings for clamping based on the spline or keyway position of the part. The clamping and supporting method clamps the small spline end of the part and supports the outer rod portion of the part.

[0009] S2. Alignment of external splines: By designing a spline locating ring, align the center of any tooth, flatten the outer circumference of the spline locating ring, insert the spline locating ring into the external spline to be processed so that the two fit tightly, and quickly align the angular relationship of any spline tooth by aligning the flat surface of the spline locating ring; then use the method of dividing the work steps to carry out the processing;

[0010] S3. Alignment of internal splines: Design the spline bushing, align the center of any tooth and directly flatten 3-6 teeth;

[0011] S4. Designing a forming column milling cutter according to the requirements of the rounded dimensions of the spline profile;

[0012] S5. Construct a two-dimensional or three-dimensional spline model of corresponding size, wherein the spline model is consistent with the actual size of the part.

[0013] Furthermore, if the part interferes with the tool, an angle head is used to clamp the tool for processing.

[0014] Furthermore, in step S2, the method of dividing the work steps includes step one and step two. In step one, the elastic bushing is connected to the part and the part is clamped; the spline locating ring is inserted into the spline to be processed, and the plane above the spline locating ring is aligned on the machine tool to complete the 0° angular positioning of the machine tool; the spline locating ring is removed, and the machine tool G54 coordinate "0" point is found, that is, the large end face of the part.

[0015] Furthermore, the step 1 is clamped in a one-clamp-one-support manner, and the tool is perpendicular to the spline surface.

[0016] Furthermore, in the second step, the elastic bushing is connected to the part and the part is clamped; the spline locating ring is inserted into the spline to be processed, and the plane above the spline locating ring is aligned on the machine tool to complete the 0° angular positioning of the machine tool; the spline locating ring is removed, and the machine tool G54 coordinate "0" point is found, that is, the inner end face of the spline; the angle head is used to clamp and start the machine tool.

[0017] Furthermore, the second step adopts a one-clamp-one-pushing method for clamping, and uses an angle head to clamp the tool for processing. The one-clamp-one-pushing method is to clamp the big head spline end of the part and support the end face of the part.

[0018] Furthermore, in step S3, the parts are clamped in a one-clamp-one-support manner, and copper sheets are provided at the clamping position.

[0019] Furthermore, in step S4, the arc size of the forming column milling cutter is controlled within the design tolerance range of the spline surface fillet, the diameter size of the arc included in the forming column milling cutter is less than 2 times the arc R of the spline bottom, and the chamfers α and β at both ends of the arc of the forming column milling cutter are not less than 5°.

[0020] Furthermore, in step S5, on a horizontal machining center, a complete concave arc and an adjacent major diameter of the spline are selected as a tool path according to the number of teeth of the spline.

[0021] Furthermore, in step S5, a complete spline profile is selected as a tool path on a vertical machining center; the tool feed and retract method is tangential, and the tool speed and feed rate are selected according to the part material and the tool diameter.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adopts a clamping scheme of one clamp and one support or direct clamping; according to whether there are features such as splines and keyways at the clamping position of the parts that are inconvenient for clamping the parts, clamping is performed by designing elastic bushings; by designing a spline locating ring and aligning the center of any tooth, the outer cylindrical surface of the locating ring is flattened, and the spline locating ring is inserted into the external spline to be processed to ensure that the two are tightly matched, and the internal and external splines are aligned. The circular surfaces at both ends of the external spline are processed by a method of divided work steps, and the internal spline is directly clamped by one clamp and one support. The tool can be perpendicular to the spline surface during processing, and processing is performed by designing a formed cylindrical milling cutter; compared with the traditional manual spline chamfering method, the method proposed by the present invention has high processing quality, and the spline surface chamfering is processed by a formed cylindrical milling cutter, and the dimensional consistency is good, which can effectively improve the reliability and stability of the spline connection.

[0024] 2. The present invention is based on part features and machine tool types. By extracting the outline of the spline surface in the programming software, G code can be quickly generated. It has a wide processing range and can also be used for rounding of gear surfaces or similar special surfaces.

[0025] 3. Based on the requirements of part clamping and spline alignment, design necessary elastic bushings, spline locating rings or spline bushings to avoid clamping marks on the splines when parts are clamped. More importantly, designing spline locating rings, spline bushings or roller-containing alignment tooling can improve processing accuracy and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the process for rounding the end face of an external spline part according to the present invention (step 1);

[0027] Figure 2 for Figure 1 Side view of the part in the figure;

[0028] Figure 3 It is a schematic diagram of the elastic bushing structure of the present invention;

[0029] Figure 4 A schematic diagram of the elastic bushing structure of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the spline positioning ring of the present invention;

[0031] Figure 6 A side view of the spline locating ring structure of the present invention;

[0032] Figure 7 AA sectional view of the spline positioning ring structure of the present invention;

[0033] Figure 8 Schematic diagram of the process for rounding the end face of an external spline part according to the present invention (process step 2);

[0034] Figure 9 for Figure 8 Side view of the part in the figure;

[0035] Figure 10 Schematic diagram of the surface rounding process of the internal spline of the present invention;

[0036] Figure 11 is a cross-sectional view of a spline bushing of the present invention;

[0037] Figure 12 This is a cross-sectional view of the spline bushing of the present invention taken along plane AA;

[0038] Figure 13 A side view of a spline bushing according to the present invention;

[0039] Figure 14 The figure is a schematic diagram of the surface rounding process at the end face of the assembled external spline part (process step 1);

[0040] Figure 15 The figure is a schematic diagram of the surface rounding process at the end face of the assembled external spline part (process step 2);

[0041] Figure 16 This is a schematic diagram of the surface rounding of the internal spline after the part is assembled with the spline bushing;

[0042] Figure 17 A structural diagram of a forming column milling cutter according to the present invention;

[0043] Figure 18 Schematic diagram of the spline surface rounding tool of the present invention.

[0044] In the figure, 1. Part; 2. Center stand support end; 3. Spline locating ring; 4. Elastic bushing; 5. Addendum circle; 6. Root circle; 7. Roller bar; 8. Involute starting circle; 9. Pitch circle; 10. Involute ending circle; 11. Part clamping position; 12. Part end face; 13. Spline bushing; 14. Tool path; 15. Forming column milling cutter. DETAILED DESCRIPTION

[0045] In order to clearly illustrate the technical features of the application scheme of the present invention, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0046] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0047] Example 1

[0048] like Figure 1 As shown, a processing method for rounding the inner and outer spline surfaces includes the following steps:

[0049] S1. For the rounding of spline surface in CNC machining center, a clamping method of one clamp and one support or direct clamping is adopted; according to the position of spline or keyway of the clamping part 11, the clamping is performed by designing elastic bushing 4 or spline bushing 13; Figure 1 and Figure 14 As shown, the one-clamp-one-support method is to clamp the small head spline end of the part 1 and support the outer rod part of the part 1;

[0050] S2. Alignment of external splines: Design a spline locating ring 3 and align the center of any tooth. Flatten the outer circumference of the spline locating ring 3. Insert the spline locating ring 3 into the external spline to be machined so that the two fit tightly. Align the flat surface of the spline locating ring 3 to quickly align the angular relationship of any tooth of the spline. Then, use the method of dividing the work steps to carry out the machining.

[0051] S3. Alignment of internal splines: Based on the same principle as in step S2, design a spline bushing 13, align the center of any tooth and directly flatten 3-6 teeth to meet the requirements of subsequent alignment and flattening.

[0052] S4. Designing a forming column milling cutter 15 according to the requirements of the rounded dimensions of the spline profile;

[0053] S5. Construct a two-dimensional or three-dimensional spline model of corresponding dimensions. The spline model is consistent with the actual dimensions of the part. The parameters used for reference to determine whether the spline model is consistent are the distinction between internal and external splines, major diameter, minor diameter, tooth bottom fillet radius, number of teeth, diametral pitch, and pressure angle.

[0054] According to the requirements of part 1 clamping and spline alignment, elastic bushing 4, spline locating ring 3 or spline bushing 13 are designed to avoid clamping marks on the spline when the part is clamped. More importantly, by designing spline locating ring 3, spline bushing 13 or roller 7 alignment tooling, the processing accuracy and efficiency can be improved.

[0055] As shown in the figure, in this embodiment, for the surface fillet processing at both end faces of the external spline part, the total length of part 1 is about 580 mm, the number of external spline teeth is 36, the module is 2.5, the pressure angle is 30°, the major diameter is Ф92.5, the minor diameter is Ф86, the tooth bottom radius is R1, the spline width is 26 mm, and the spline surface fillet R1 is considered. Considering that the spline surface away from the part end face 12 is difficult to be processed by conventional tools, this example adopts a step-by-step method for processing, such as Figure 1 and Figure 14 As shown, the first step adopts a clamping and supporting clamping, and the small head spline end of the part 1 is clamped and clamped by the elastic bushing 4, and supported by the center frame at the center frame support end 2, and the tool is perpendicular to the spline surface during processing; as shown in Figure 8 and Figure 15 As shown, the second step adopts one clamp and one top clamping, using the elastic bushing 4 to clamp the big head spline end of the part 1 and clamp it, holding the end face 12 of the part, and using the angle head to clamp the tool for processing. The specific processing steps and tooling drawings are shown in Figures 1 to 9 shown.

[0056] As shown in the figure, the operation steps for the surface rounding process at the end face of the external spline part are as follows:

[0057] 1) Connect the elastic bushing 4 to the part 1 and clamp the part 1 in a one-clamp-one-support manner;

[0058] 2) Insert the spline locating ring 3 into the spline to be processed, align the upper plane of the spline locating ring 3 on the machine tool, and complete the 0° positioning of the machine tool;

[0059] 3) Remove the spline locating ring 3 and find the G54 coordinate "0" point of the machine tool, which is the large end face of part 1;

[0060] 4) Start the machine tool and complete the first step of processing.

[0061] As shown in the figure, the steps for the surface rounding process at the inner end face of the external spline are as follows:

[0062] 1) Connect the elastic bushing 4 to the part 1 and clamp the part 1 in a one-clip and one-pushing manner;

[0063] 2) Insert the spline locating ring 3 (semicircular) into the spline to be processed, align the upper plane of the spline locating ring 3 on the machine tool, and complete the 0° positioning of the machine tool;

[0064] 3) Remove the spline locating ring 3 and find the G54 coordinate "0" point of the machine tool, which is the inner end face of the spline of part 1;

[0065] 4) Use the angle head to clamp and start the machine tool to complete the processing of step 2.

[0066] Example 2

[0067] As shown in the figure, a processing method that can be used for rounding the internal and external spline surfaces includes the following steps:

[0068] S1. When performing rounding of the spline surface in a CNC machining center, a clamping method of one clamp and one support or direct clamping is adopted; according to the position of the spline or keyway of the part clamping part 11, the elastic bushing 4 or the spline bushing 13 is designed for clamping; Figure 1 As shown, the one-clamp-one-support method is to clamp the small head spline end of the part 1 and support the outer rod part of the part 1;

[0069] S2. Alignment of external splines: Design a spline locating ring 3 and align the center of any tooth. Flatten the outer surface of the spline locating ring 3. Insert the spline locating ring 3 into the external spline to be machined, ensuring that the two fit tightly. Align the flat surface of the spline locating ring 3 to quickly align the angular relationship of any spline tooth. Machining is performed in a divided step method.

[0070] S3, align the internal spline, design the spline bushing 13 based on the same principle as in step S2, align the center of any tooth and directly flatten 3-6 teeth, and meet the requirements of subsequent alignment and flattening;

[0071] S4. Design a forming column milling cutter 15 according to the designed spline surface fillet size requirements;

[0072] S5. Construct a two-dimensional or three-dimensional spline model of the corresponding size to ensure that the model matches the actual size of part 1. The matching parameters are the distinction between internal and external splines, major diameter, minor diameter, tooth bottom fillet radius, number of teeth, diametral pitch, and pressure angle.

[0073] As shown in the figure, in this embodiment, for the internal spline surface fillet, the total length of part 1 is about 310mm, the number of internal spline teeth is 24, the module is 2.5, the pressure angle is 30°, the major diameter is Ф63.5, the minor diameter is Ф57.5, the tooth bottom radius is R0.5mm, the spline width is 30mm, and the spline surface fillet is R0.4. Part 1 is clamped directly using a one-clamp-one-support method. The small head spline end of part 1 is clamped and clamped using an elastic bushing 4. The center frame is used to support the center frame support end 2. The tool can be perpendicular to the spline surface during processing. The specific clamping scheme and tooling drawings are shown in the figure. Figure 10-13 as well as Figure 2 shown.

[0074] For the internal spline surface rounding process, the specific steps are as follows:

[0075] 1) Directly clamp part 1 in a one-clamp-one-support manner, and pad copper foil at the part clamping portion 11 to prevent part 1 from being clamped;

[0076] 2) Insert the spline bushing 13 into the internal spline to be processed, align the upper plane of the spline bushing 13 on the machine tool, and complete the 0° angular positioning of the machine tool;

[0077] 3) Remove the spline bushing 13 and find the G54 coordinate "0" point of the machine tool;

[0078] 4) Start the machine tool and complete the spline surface rounding process.

[0079] Example 3

[0080] In this embodiment, if Figure 17 As shown, according to the requirements of the designed spline surface fillet, the forming column milling cutter 15 is designed. Generally, according to the requirements of the spline surface fillet size, the arc size R of the forming column milling cutter 15 needs to be within the design tolerance range of the spline surface fillet, the diameter size ФA of the arc of the forming column milling cutter 15 is less than 2 times the R size of the spline bottom, and the chamfers α and β at both ends of the arc of the forming column milling cutter 15 are not less than 5° to avoid interference with the spline end face and the major diameter.

[0081] In this embodiment, the forming column milling cutter 15 is set to a conventional cylindrical milling cutter with a diameter of ФA through programming software. On a horizontal machining center, the tool path 14 can be selected according to the number of teeth of the spline to select a complete concave arc and the major diameter of the spline adjacent to it, such as Figure 18 If it is on a vertical machining center, you can select tool path 14 as a complete spline surface. Finally, it is particularly important that the tool processing depth value in the programming software should be Figure 17 The machining depth value L in the figure is set, the feed and retract method is tangential, and the tool speed and feed are selected according to the part material and tool diameter. In this way, the forming column milling cutter 15 can be used to complete the rounding of the spline surface.

[0082] In addition, for parts that are smaller in size and require rounding, a fixture with multiple clamps can be designed, and a positioning mechanism for any tooth of the spline can be designed on the fixture. The rounding of the surfaces of multiple parts can be completed in one clamping. The processing efficiency is significantly improved compared to traditional bench rounding, and the processing quality and surface integrity are significantly improved.

[0083] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make other variations or modifications based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A processing method for rounding the internal and external spline surfaces, characterized in that: The following steps are involved: S1. The spline surface is rounded on the CNC machining center, using a one-clamp-one-support or direct clamping method; according to the position of the spline or keyway of the clamping part, elastic bushings or spline bushings are designed for clamping; S2. Alignment of external splines: By designing a spline locating ring, align the center of any tooth, flatten the outer circumference of the spline locating ring, insert the spline locating ring into the external spline to be processed so that the two fit tightly, and quickly align the angular relationship of any spline tooth by aligning the flat surface of the spline locating ring; then use the method of dividing the work steps to carry out the processing; S3. Alignment of internal splines: Design the spline bushing, align the center of any tooth and directly flatten 3-6 teeth; S4. Designing a forming column milling cutter according to the requirements of the rounded dimensions of the spline profile; S5. Construct a two-dimensional or three-dimensional spline model of corresponding size, wherein the spline model is consistent with the actual size of the part.

2. A processing method for rounding the internal and external spline surfaces according to claim 1, characterized in that: When the part interferes with the tool, an angle head is used to clamp the tool for processing.

3. A processing method for rounding the internal and external spline surfaces according to claim 1, characterized in that: In step S2, the method of dividing the work steps includes step one and step two. In step one, the small head spline end of the part is clamped by using an elastic bushing; the spline locating ring is inserted into the spline to be processed, and the plane above the spline locating ring is aligned on the machine tool to complete the 0° angular positioning of the machine tool; the spline locating ring is removed, and the machine tool G54 coordinate "0" point is found, that is, the large end face of the part.

4. A processing method for rounding the internal and external spline surfaces according to claim 3, characterized in that: The first step adopts a one-clamp-one-support method for clamping, and the tool is perpendicular to the spline surface.

5. A processing method for rounding the internal and external spline surfaces according to claim 3, characterized in that: In the second step, the big head spline end of the part is clamped by using an elastic bushing; the spline locating ring is inserted into the spline to be processed, and the upper plane of the spline locating ring is aligned on the machine tool to complete the 0° angular positioning of the machine tool; the spline locating ring is removed, and the machine tool G54 coordinate "0" point is found, that is, the inner end face of the spline; the angle head is used to clamp and start the machine tool.

6. A processing method for rounding the internal and external spline surfaces according to claim 5, characterized in that: The second step adopts a one-clamp-one-pushing method for clamping, and uses an angle head to clamp the tool for processing.

7. A processing method for rounding the internal and external spline surfaces according to claim 1, characterized in that: In step S3, the parts are clamped in a one-clamp-one-support manner, and copper sheets are provided at the clamping locations.

8. A processing method for rounding the internal and external spline surfaces according to claim 1, characterized in that: In step S4, the arc size of the forming column milling cutter is controlled within the design tolerance range of the spline surface fillet, the diameter of the arc of the forming column milling cutter is less than 2 times the radius of the arc of the spline bottom, and the chamfers α and β at both ends of the arc of the forming column milling cutter are not less than 5°.

9. A processing method for rounding the internal and external spline surfaces according to claim 1, characterized in that: In step S5, on a horizontal machining center, a complete concave arc and an adjacent major diameter of the spline are selected as a tool path according to the number of teeth of the spline.

10. A processing method for rounding the internal and external spline surfaces according to claim 1, characterized in that: In step S5, a complete spline profile is selected as a tool path on a vertical machining center; the tool feed and retraction mode is tangential, and the tool speed and feed rate are selected according to the part material and tool diameter.

Images