Machining method capable of being used for rounding molded surfaces of internal and external splines

Abstract

The invention discloses a processing method for rounding internal and external spline molded surfaces, which comprises the following steps of: S1, adopting a clamping mode of one clamping and one supporting or direct clamping, and clamping by designing an elastic bushing or a spline bushing; s2, aligning an external spline by designing a spline positioning ring, and machining by adopting a step-by-step method; s3, a spline bushing is designed based on the same principle in the step S2, and an internal spline is aligned; s4, designing a forming column milling cutter; s5, constructing a two-dimensional or three-dimensional spline model of the corresponding size; according to the method, the machining quality is high, and the reliability and stability of spline connection can be effectively improved.

Description

Technical Field

[0001] The 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 profiles. Background Art

[0002] Splines include internal splines and external splines. Spline connection is a common mechanical connection method. In the design of splines, rounding the spline surface can effectively reduce stress concentration and improve the fatigue strength and fracture resistance of parts. On the other hand, the rounding 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 rounding of the spline surface can effectively prevent 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] The patent with the publication number CN214350631U discloses an external spline fillet rolling tool, including a stud bolt and a body, the stud bolt is located inside the body, one end of the stud bolt is provided with a sleeve, the stud bolt and the sleeve are connected by a thread, the top of the sleeve is provided with a spring, a washer and a nut in sequence, and the nut is threadedly connected to the body, the outer surface of the body is provided with an opening, the outer surface of the body is provided with a dial at a position corresponding to the opening, a first screw is provided between the dial and the body, and a ruler is provided on the outer surface of the dial. In the utility model, by designing a special rolling tool, after each clamping of the parts, the rolling processing of all spline fillets is completed continuously on the lathe; the external spline fillet rolling tool disclosed in the patent has a high manufacturing cost, the processing quality of the spline profile fillet depends on the quality of the tool, and the internal spline profile cannot be rounded. Summary of the invention

[0005] The present invention mainly aims at the prior art, in which the spline surface is complex and the tool design and program compilation are difficult, and manual chamfering and rounding are mostly performed by fitters, so that the rounding size of the spline surface is difficult to meet the design requirements and the size consistency is poor. A processing method 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 internal and external spline surfaces comprises the following steps:

[0008] S1. The spline surface is rounded on a CNC machining center, using a clamping and supporting or direct clamping method; according to the position of the spline or keyway of the clamping part, an elastic bushing or a spline bushing is designed for clamping; the one-clamping and supporting method is to clamp the small head spline end of the part and support the outer round rod of the part;

[0009] S2. Alignment of external splines: by designing a spline locating ring, align the center of any tooth, flatten the outer cylindrical surface 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 tooth of the spline by aligning the flat surface of the spline locating ring; then use the method of divided work steps to process;

[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 rounding size 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 "0" point of the machine tool G54 coordinate 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 "0" point of the machine tool G54 coordinate 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 foil is 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 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, on a vertical machining center, a complete spline profile is selected as a tool path; the tool advance 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, the spline locating ring is inserted into the external spline to be processed to ensure that the two are closely matched, the internal and external splines are aligned, and the circular surfaces at both ends of the external spline are processed by a method of dividing work steps, and the internal spline is directly clamped by one clamp and one support, and the tool is perpendicular to the spline profile during processing, and processing is performed by designing a formed cylindrical milling cutter; compared with the traditional manual spline rounding processing method, the method proposed by the present invention has high processing quality, and the formed cylindrical milling cutter is used to process the spline profile rounding, 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, the 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. According to the requirements of part clamping and spline alignment, necessary elastic bushings, spline locating rings or spline bushings are designed to avoid clamping marks on the splines when parts are clamped. More importantly, the design of 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 profile at the end face of an external spline part of the present invention (process 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 It 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 It is a cross-sectional view of the spline positioning ring structure AA of the present invention;

[0033] Figure 8 The figure is a schematic diagram of the process for rounding the profile at the end face of an external spline part of the present invention (process step 2);

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

[0035] Fig.10 It is a schematic diagram of the surface rounding process of the internal spline of the present invention;

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

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

[0038] Fig.13 It is a side view of the spline bushing of the present invention;

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

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

[0041] Fig.16 The schematic diagram of the surface rounding of the internal spline after the part is assembled with the spline bushing;

[0042] Fig.17 It is a structural diagram of the forming column milling cutter of the present invention;

[0043] Fig.18 It is a schematic diagram of the spline surface rounding tool of the present invention.

[0044] In the figure, 1. part; 2. center frame support end; 3. spline locating ring; 4. elastic bushing; 5. tooth top circle; 6. tooth root circle; 7. rolling rod; 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 profiles includes the following steps:

[0049] S1. For the rounding of the spline surface in the 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 and Fig.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 round rod part of the part 1;

[0050] S2. Alignment of external splines: by designing a spline positioning ring 3 and aligning the center of any tooth, flattening the outer cylindrical surface of the spline positioning ring 3, inserting the spline positioning ring 3 into the external spline to be processed so that the two fit closely, and quickly aligning the angular relationship of any tooth of the spline by aligning the flat surface of the spline positioning ring 3; and then using the method of dividing the work steps for processing;

[0051] S3, aligning the inner spline: designing the spline bushing 13 based on the same principle as in step S2, aligning the center of any tooth and directly flattening 3-6 teeth to meet the subsequent alignment and flattening of the surface;

[0052] S4, designing a forming column milling cutter 15 according to the requirements of the rounded size of the spline profile;

[0053] S5. Construct a two-dimensional or three-dimensional spline model of corresponding size. The spline model is consistent with the actual size of the part. The reference parameters for whether it 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 splines when the parts are clamped. More importantly, spline locating ring 3, spline bushing 13 or roller 7 alignment tooling are designed to improve processing accuracy and efficiency.

[0055] As shown in the figure, in this embodiment, for the surface rounding processing at both end faces of the external spline part, the total length of part 1 is about 580mm, 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 26mm, and the spline surface rounding is R1. Considering that the spline surface away from the end face 12 of the part is difficult to be processed by conventional tools, this example adopts the method of dividing the work steps, such as Figure 1 and Fig.14 As shown, the first step adopts a clamp-support 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 Fig.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° angular positioning of the machine tool;

[0059] 3) Remove the spline locating ring 3 and find the "0" point of the machine tool G54 coordinate, 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 by a one-clip and one-pushing method;

[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° angular positioning of the machine tool;

[0064] 3) Remove the spline locating ring 3 and find the "0" point of the machine tool G54 coordinate, 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 inner and outer spline profiles 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 round rod part of the part 1;

[0069] S2. Alignment of external splines: by designing a spline positioning ring 3 and aligning the center of any tooth, flattening the outer cylindrical surface of the spline positioning ring 3, inserting the spline positioning ring 3 into the external spline to be processed, ensuring that the two are closely matched, and quickly aligning the angular relationship of any tooth of the spline by aligning the flat surface of the spline positioning ring 3; the processing is carried out by adopting a method of divided work steps;

[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 subsequent alignment and flattening of the surface;

[0071] S4. Design a forming column milling cutter 15 according to the designed spline profile rounding dimension requirements;

[0072] S5. Construct a two-dimensional or three-dimensional spline model of corresponding dimensions to ensure that the model is consistent with the actual dimensions of part 1. The consistent 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 rounding, 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 rounding is R0.4. Directly use one clamp and one support to clamp part 1, use elastic bushing 4 to clamp the small head spline end of part 1 and clamp it, and use the center frame to support it at the center frame support end 2. The tool can be perpendicular to the spline surface during processing. The specific clamping plan and tooling drawings are as 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 by one clamp and one support, and pad copper sheet at the part clamping part 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 angular positioning of the machine tool at 0°;

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

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

[0079] Example 3

[0080] In this embodiment, if Fig.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 select a complete concave arc and a major diameter of the spline adjacent to a spline according to the number of teeth of the spline, such as Fig.18 If it is on a vertical machining center, you can select the complete spline profile for tool path 14. Finally, it is particularly important that the tool processing depth value in the programming software should be Fig.17 The processing depth value L in the figure is tangential, the feed and retract method is tangential, and the tool speed and feed are selected according to the part material and the 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 and require rounding, a one-machine-multiple-clamp fixture 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 clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope 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 clamping method of one clamp and one support or direct clamping; according to the position of the spline or keyway of the clamping part, an elastic bushing or spline bushing is designed for clamping; S2. Alignment of external splines: by designing a spline locating ring, align the center of any tooth, flatten the outer cylindrical surface 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 tooth of the spline by aligning the flat surface of the spline locating ring; then use the method of divided work steps to process; 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 rounding size 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 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 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 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.

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

5. A processing method for rounding the inner and outer spline surfaces according to claim 3, characterized in that: 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 "0" point of the machine tool G54 coordinate 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 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 internal and external spline surfaces according to claim 1, characterized in that: In the step S3, the parts are clamped in a one-clamp-one-support manner, and copper foil is provided at the clamping position.

8. A processing method for rounding 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 included in the forming column milling cutter is less than 2 times the arc R at the bottom of the spline, 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 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 a major diameter of the spline adjacent to the spline are selected as a tool path according to the number of teeth of the spline.

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

Images