Rounding machining method for tooth crest molded surface of external spline

Abstract

The invention discloses a rounding machining method for an external spline tooth crest molded surface. The rounding machining method comprises the following steps that S1, a forming column milling cutter is adopted for directly feeding along the edge of the spline tooth crest molded surface; s2, calculating the rotation angle of the cutter and the part by using a formula according to known data; s3, measuring a transverse coordinate and a longitudinal coordinate from the rotation center of the cutter to the center of the spline; s4, a numerical control program is manually programmed, the part is clamped through a tool, the center of any tooth of the spline is aligned through metering, and angular 0-degree positioning of the machine tool is completed; s5, finding a G54 coordinate 0 point of the machine tool, and starting the machine tool to complete part machining; compared with a traditional manual spline tooth crest profile rounding method, the spline tooth crest profile rounding method is high in machining quality, good in size consistency and high in efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and in particular relates to a rounding processing method for an external spline tooth top profile. Background Art

[0002] Spline connection is a connection formed by placing a shaft with multiple evenly distributed convex teeth in the corresponding grooves of the wheel hub. Spline connection is generally used in places with high centering accuracy requirements, large torque transmission or frequent slippage. Spline tooth top profile rounding refers to the rounding of the tooth top part of the spline. Its purpose is to provide a smooth transition between the tooth side surface and the tooth top circle, thereby improving the performance of the spline and reducing stress concentration, and increasing the wear resistance and life of the gear.

[0003] However, in actual engineering applications, since the external spline tooth top circle is generally formed before the spline is formed, and the later spline is formed after processing such as gear shaping, gear hobbing, and gear grinding, the spline tooth top profile is also formed accordingly. In order to complete the chamfering of the external spline tooth top profile, due to the difficulty of tool design and program compilation, the existing technology mostly uses manual chamfering by fitters and then chamfering, which makes it difficult for the chamfering size of the external spline tooth top profile to meet the design requirements, the size consistency is poor, and the processing quality and processing efficiency are low.

[0004] The patent with the publication number of 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 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, so the applicability is not high. Summary of the invention

[0005] The present invention mainly aims at the problem that the conventional spline tooth top surface chamfering in the prior art is mostly performed by fitters or special tooling, which has poor dimensional consistency and high manufacturing cost. A CNC machining method for chamfering the spline tooth top surface using a forming column milling cutter is proposed.

[0006] The technical solution of the present invention is as follows:

[0007] A rounding processing method for an external spline tooth top profile comprises the following steps:

[0008] S1, using a forming column milling cutter to directly feed along the edge of the spline tooth top profile, the arc radius of the forming column milling cutter is consistent with the rounding size requirement of the spline tooth top profile;

[0009] S2. When the forming column milling cutter is used to mill the spline tooth top profile, the forming column milling cutter is rotated by a certain angle so that the upper and lower transition angles α and β of the forming column milling cutter avoid the spline tooth top circle and the spline tooth profile surface;

[0010] S3, compile a CNC program, wait for the forming column milling cutter to rotate to a certain angle, feed along the arc center of the forming column milling cutter, and after the feed point is determined, measure the horizontal coordinate Y of the tool rotation center from the spline center at this time X With the longitudinal coordinate Z X ;

[0011] S4. Clamp the parts, find the center of any tooth of the spline to be processed, define the spline angle at this time as 0°, rotate the spline forward or reverse, and the spline rotation angle is α 件 , then the horizontal coordinate Y X , vertical coordinate Z X , tool rotation angle α 刀 、Part rotation angle α 件 The spline width is written into the program, and the processing is cyclic according to the number of teeth, and the program of the rounding processing of the right side tooth top profile of the entire spline involute is completed; then the tool is rotated in the opposite direction α 刀 , the part rotates in the opposite direction α 件 , and complete the programming of the rounding process of the left side tooth top surface of the entire spline involute.

[0012] S5. Find the "0" point of the machine tool G54 coordinate, that is, the large end face of the part, and start the machine tool to complete the part processing.

[0013] Furthermore, in step S2, the upper and lower transition angles α and β of the forming column milling cutter are not less than half of the pressure angle at the spline tooth top arc.

[0014] Furthermore, in step S2, after the forming column milling cutter rotates a certain angle, the tool arc and the tooth top arc intersect, and the straight line between the center of the tool arc and the intersection bisects the angle formed by the tangent of the tooth top arc and the tangent at the chamfer of the tooth top arc.

[0015] Furthermore, the pressure angle at the tooth top arc chamfer is:

[0016]

[0017] In the above formula, D b is the base circle diameter, D ceis the diameter at the roller contact point, i.e. the major diameter of the part; and D b =m*z*cos(α), where m represents the module, z represents the number of spline teeth, and α represents the spline pressure angle.

[0018] Furthermore, the angle between the tangent line of the outer circle at the major diameter of the part and the line connecting the center is 90°.

[0019] Furthermore, the rotation angle α of the forming column milling cutter is 刀 for

[0020] α 刀 =(α ce +90°)÷2-45°=(cos -1 (m*z*cos(α)÷D ce )+90°)÷2-45°.

[0021] Furthermore, in step S3, when the forming column milling cutter is used for cutting, the cutting depth of the tool does not exceed the required fillet R angle value.

[0022] Furthermore, in step S4, the α 件 The pressure angle α at the chamfer of the tooth tip ce And the diameter D of the measuring rod at the top arc of the tooth Re It turns out that the measuring rod diameter D Re The expression is

[0023]

[0024] In the above formula, D b is the base circle diameter, S min is the minimum value of the actual tooth thickness, D is the spline pitch circle diameter, and the α 件 The expression is

[0025]

[0026] In the above formula, D ce It is the diameter at the roller contact point, that is, the major diameter of the part.

[0027] Furthermore, in step S4, when clamping the part, a one-clamp-one-support method is adopted, that is, the small-head spline end is clamped and clamped by a fixture, and the outer cylindrical rod portion of the part is supported by a center frame.

[0028] Furthermore, in step S4, a rolling rod is used to align the center of any tooth of the spline.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention adopts a formed column milling cutter to directly feed along the edge of the spline tooth top profile, the arc radius of the formed column milling cutter is consistent with the fillet size requirement of the spline tooth top profile, and the formed column milling cutter is rotated by a certain angle so that the upper and lower transition angles α and β of the tool avoid the spline tooth top circle and the spline tooth profile; the rotation angle of the part and the tool is calculated, and the horizontal coordinate and the vertical coordinate of the tool rotation center from the spline center are measured according to the drawing software; the CNC program is manually compiled, and the part is clamped in a one-clamp-one-support manner. The center of any spline tooth is aligned on the machine tool using a roller table to complete the 0° angular positioning of the machine tool; the machine tool G54 coordinate "0" point is found, that is, the center of the large end face of the part; the above method can complete the chamfering of the external spline tooth top profile. Compared with the traditional manual spline tooth top profile filleting method, the formed column milling cutter is used to process the spline profile fillet, which has good dimensional consistency, high efficiency, and high processing quality.

[0031] 2. According to the part features and machine tool type, by extracting the horizontal and vertical coordinate values ​​of the distance from the rotation center of the forming column milling cutter to the spline center in the drawing software, and then obtaining the angle between the arc center of any spline tooth to the intersection of the tooth top circle and the spline involute, finally based on the patented tool and part rotation angle formula, the final G code that can be used for on-site processing can be quickly obtained. In addition to being used for rounding the spline tooth top profile, it can also be used for rounding the gear tooth top profile or similar special profiles, with a wide range of processing.

[0032] 3. The method described in this application can be encapsulated into a special program instruction for the rounding processing of the spline tooth top profile. It only needs to input the number of teeth, module, pressure angle, base circle diameter, major diameter, actual minimum tooth thickness and spline width required for spline processing, and then according to the size of the processing tool, the processing program can be automatically generated in the background, which is convenient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of parts clamping of the present invention;

[0034] Figure 2 It is a structural schematic diagram of the forming column milling cutter of the present invention;

[0035] Figure 3 The rotation angle of the tooth top circle milling tool of the present invention is shown in FIG. Figure 1 ;

[0036] Figure 4 The rotation angle of the tooth top circle milling tool of the present invention is shown in FIG. Figure 2 ;

[0037] Figure 5 It is a schematic diagram of the rotation angle of parts of the present invention;

[0038] Figure 6It is a schematic diagram of the angle rotation of parts and cutting tools of the present invention.

[0039] In the figure, 1. forming column milling cutter; 2. small head spline end; 3. outer cylindrical part of the part; 4. arc radius R of the forming column milling cutter; 5. tool rotation angle α 刀 ; 6. Pressure angle α at the chamfer of the tooth top arc ce ; 7. Feed direction; 8. Part rotation angle α 件 ; DETAILED DESCRIPTION

[0040] 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.

[0041] 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.

[0042] In addition, in the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0043] In the present application, unless otherwise clearly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, reference terms; "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like are intended to mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0044] Example 1

[0045] like Figure 1-Figure 6 As shown, a rounding processing method for an external spline tooth top profile includes the following steps:

[0046] S1, using the forming column milling cutter 1 to directly feed along the edge of the spline tooth top profile, the arc radius of the forming column milling cutter 1 is consistent with the rounding size requirement of the spline tooth top profile;

[0047] S2. When the forming column milling cutter 1 is used to mill the spline tooth top profile, the forming column milling cutter 1 is rotated by a certain angle so that the upper and lower transition angles α and β of the forming column milling cutter 1 avoid the spline tooth top circle and the spline tooth profile surface;

[0048] S3. Manually compile the CNC program. Draw the spline tooth profile and tool graphics in the software with drawing function. After the forming column milling cutter 1 rotates to a certain angle, feed along the arc center direction of the forming column milling cutter 1. After the feed point is determined, measure the horizontal coordinate Y of the tool rotation center from the spline center. X With the longitudinal coordinate Z X ;

[0049] S4. Use the tooling to find the center of any tooth of the spline to be processed, define the spline angle at this time as 0°, rotate the spline forward or reverse, and the spline rotation angle is α 件 8. Then, the horizontal coordinate Y of the tool rotation center from the spline center X , vertical coordinate Z X , tool rotation angle α 刀 5. Part rotation angle α 件 8 and the spline width are written into the program, and the processing is cyclic according to the number of teeth, and the program compilation of the rounding processing of the right side tooth top profile of the entire spline involute is completed; then the tool is rotated in the opposite direction α 刀 5. The part rotates in the opposite direction α 件 8. Complete the programming of the rounding process of the left side tooth top profile of the entire spline involute;

[0050] S5. Find the "0" point of the machine tool G54 coordinate, that is, the large end face of the part, and start the machine tool to complete the part processing.

[0051] like Figure 2 As shown, in this embodiment, in order to ensure the efficiency of the chamfering of the spline tooth top profile, a formed column milling cutter 1 can be used to directly feed along the edge of the tooth top profile. Compared with the use of a formed ball head milling cutter for multiple layered milling, the surface quality and efficiency of the processing in this application are significantly improved. Since the formed ball head milling cutter is a concave arc when milling the external spline tooth top profile, and the chamfered surface is a convex arc, it is necessary to feed multiple times to fit it into a "convex arc" shape.

[0052] The arc radius R of the forming column milling cutter 1 is consistent with the rounding size requirements of the tooth top profile. It is particularly important to note that the upper and lower transition angles α and β of the forming column milling cutter 1 should effectively avoid the spline tooth top circle and the spline tooth profile surface, such as Figure 2As shown, specifically, the upper and lower transition angles α and β of the forming column milling cutter 1 are not less than half of the pressure angle at the spline tooth top arc; in simple terms, for a common spline with a 30° pressure angle, the upper and lower transition angles α and β of the forming column milling cutter 1 should be no less than 15° to meet the requirements.

[0053] Furthermore, when the forming column milling cutter 1 mills the spline tooth top profile, in order to avoid the spline tooth profile, the forming column milling cutter 1 is rotated by a certain angle, such as Figure 3 As shown in the figure, after the tool rotates, the tool arc and the tooth top arc intersect, and the straight line between the center of the tool arc and the intersection (shown by the dotted line in the figure) is the bisector of the angle formed by the tangent line of the tooth top arc and the pressure angle 6 (line) at the tooth top arc where chamfering is required, to ensure that the tool does not overcut the spline tooth top arc during processing, and to ensure that both ends of the spline tooth top circle are evenly chamfered. The pressure angle 6 at the tooth top arc where chamfering is required is

[0054]

[0055] In the above formula, D b is the base circle diameter, D ce is the diameter at the roller contact point, that is, the major diameter of the part at this time; and D b =m*z*cos(α), where m represents the module, z represents the number of spline teeth, α represents the spline pressure angle, the angle between the tangent line of the outer circle at the major diameter of the part and the line connecting the center is 90°, and the rotation angle α of the forming column milling cutter 1 刀 5 for

[0056] α 刀 =(α ce +90°)÷2-45°=(cos -1 (m*z*cos(α)÷D ce )+90°)÷2-45°

[0057] like Figure 4 As shown, in this embodiment, the CNC program of the present application is manually programmed. Therefore, after knowing the law of the rotation angle of the above-mentioned forming column milling cutter 1, according to the accurate cutting point of the tool, the spline tooth profile and the tool can be directly drawn in a software with a drawing function at a 1:1 ratio. After the tool is rotated to a good angle, the tool is fed along the center of its arc, so that the tool increases the cutting depth as much as possible without interfering with the spline profile, and the cutting depth does not exceed the required chamfer R angle value; after the feed point is confirmed, the horizontal coordinate Y of the rotation center of the tool from the spline center is measured. X With the longitudinal coordinate Z X .

[0058] like Figure 1As shown in the figure, by designing a fixture and clamping the parts in a one-clamp-one-support manner, the small head spline end 2 can be clamped and tightened by an elastic bushing and a spline locating ring, and the outer cylindrical rod 3 of the part is supported by a center stand. The center of any tooth of the spline to be processed is aligned by a matching roller, and the spline angular direction at this time is defined as the "0°" angular direction, and then the spline is rotated forward or reversed α 件 8, such as Figure 5 As shown, then the lateral coordinate Y of the tool rotation center from the spline center X , vertical coordinate Z X , tool rotation angle α 刀 5. Part rotation angle α 件 8 and the spline width are written into the program, and the processing is repeated according to the number of teeth. In this way, the program compilation of the rounding processing of the right side tooth top profile of the entire spline involute is completed. Next, just rotate the tool and the part in opposite directions α 刀 5 and α 件 8, and the program compilation of the rounding processing of the left side tooth top profile of the entire spline involute can be completed.

[0059] Specifically, α 件 8 Pressure angle α at the chamfer of the tooth tip ce 6 and the diameter of the measuring rod at the top arc of the tooth D Re It turns out that the measuring rod diameter D Re The expression is

[0060]

[0061] In the above formula, D b is the base circle diameter, S min is the minimum value of the actual tooth thickness, D is the spline pitch circle diameter, and the α 件 The expression for 8 is

[0062]

[0063] In the above formula, D ce It is the diameter at the roller contact point, that is, the major diameter of the part.

[0064] Example 2

[0065] like Figure 1 As shown, in this embodiment, the external spline tooth top profile of the part needs to be rounded R0.2, the number of external spline teeth of the part 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, and the spline width is 26mm. The part is clamped in a one-clamp-one-support manner, and the spline to be rounded is located on the right side of the part.

[0066] like Figure 6 As shown, the steps for rounding the external spline tooth top profile are as follows:

[0067] (1) According to the spline parameters to be processed and the tip circle to be rounded R0.2, compare Figure 1 , select the forming column milling cutter 1 with ФA of 1.3mm, α and β angles of 30 degrees, and R cutter of 0.2mm;

[0068] (2) Based on Figure 6 Calculate the rotation angle of the part, α 件 8 Pressure angle α at the chamfer of the tooth tip ce 6 and the diameter of the measuring rod at the tooth top arc D Re It is concluded that according to the diameter D of the measuring rod Re The expression of

[0069]

[0070] In the above formula, D b is the base circle diameter, S min is the minimum value of the actual tooth thickness. According to the diameter of the measuring rod calculated above, α 件 The value of 8 is

[0071]

[0072] In the above formula, D ce is the diameter at the roller contact point, i.e. the major diameter of the part;

[0073] (3) Calculate the tool rotation angle: Substitute the formula and data to get

[0074] α 刀 =(α ce +90°)÷2-45°=(cos -1 (m*z*cos(α)÷D ce )+90°)÷2-45°=16.2°

[0075] (4) According to the drawing software, measure the horizontal coordinate Y of the tool rotation center from the spline center X 0.94mm, longitudinal coordinate Z X is 45.92mm, and the part rotation angle α 件 8 is 3.5°;

[0076] (5) Manually compile the NC program based on the above data;

[0077] (6) The parts are clamped by a one-clamp-one-support method, and a roller with a diameter of 4.2 mm is used on the machine tool to align the center of any tooth of the spline to complete the 0° angular positioning of the machine tool;

[0078] (7) Find the "0" point of the machine tool G54 coordinate, that is, the large end face of the part;

[0079] (8) Start the machine tool and complete parts processing.

[0080] Example 3

[0081] like Figures 1 to 6 As shown, a method for rounding the external spline tooth top profile is provided. In this embodiment, the method of the present application can be used not only for rounding the spline tooth top profile, but also for rounding the gear tooth top profile and other similar profiles. For rounding the internal spline tooth top profile, it is only necessary to ensure that the tool does not interfere with the part, such as using an angle head to clamp the tool to complete the processing; if a forming chamfering tool is used, it can also be used for chamfering special profiles.

[0082] For the chamfering of the spline tooth top profile of smaller parts, a one-machine-multiple-clamp tooling can be designed, and a spline positioning device with the same angular relationship can be designed on the fixture. The chamfering of the spline tooth top profile of multiple parts can be completed by only aligning the spline angle at one place. This method is not affected by whether the machine tool is vertical or horizontal, and the processing is more convenient.

[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 rounding method for external spline tooth top profile, characterized in that: The following steps are involved: S1, using a forming column milling cutter to directly feed along the edge of the spline tooth top profile, the arc radius of the forming column milling cutter is consistent with the rounding size requirement of the spline tooth top profile; S2. When the forming column milling cutter is used to mill the spline tooth top profile, the forming column milling cutter is rotated by a certain angle so that the upper and lower transition angles α and β of the forming column milling cutter avoid the spline tooth top circle and the spline tooth profile surface; S3, compile a CNC program, wait for the forming column milling cutter to rotate to a certain angle, feed along the arc center of the forming column milling cutter, and after the feed point is determined, measure the horizontal coordinate Y of the tool rotation center from the spline center at this time X With the longitudinal coordinate Z X ; S4. Clamp the parts, find the center of any tooth of the spline to be processed, define the spline angle at this time as 0°, rotate the spline forward or reverse, and the spline rotation angle is α 件 , then the horizontal coordinate Y X , vertical coordinate Z X , tool rotation angle α 刀 、Part rotation angle α 件 The spline width is written into the program, and the processing is cyclic according to the number of teeth, and the program of the rounding processing of the right side tooth top profile of the entire spline involute is completed; then the tool is rotated in the opposite direction by α 刀 , the part rotates in the opposite direction α 件 , and complete the programming of the rounding process of the left side tooth top profile of the entire spline involute; S5. Find the G54 coordinate "0" point of the machine tool and start the machine tool to complete part processing.

2. A rounding method for external spline tooth top profile according to claim 1, characterized in that: In the step S2, the upper and lower transition angles α and β of the forming column milling cutter are not less than half of the pressure angle at the spline tooth top arc.

3. A rounding method for external spline tooth top profile according to claim 1, characterized in that: In step S2, after the forming column milling cutter rotates a certain angle, the tool arc and the tooth top arc intersect, and the straight line between the center of the tool arc and the intersection bisects the angle formed by the tangent of the tooth top arc and the tangent at the chamfer of the tooth top arc.

4. A rounding method for external spline tooth top profile according to claim 3, characterized in that: The pressure angle at the tooth top arc chamfer is: In the above formula, D b is the base circle diameter, D ce is the diameter at the roller contact point, i.e. the major diameter of the part; and D b =m*z*cos(α), where m represents the module, z represents the number of spline teeth, and α represents the spline pressure angle.

5. A rounding method for external spline tooth top profile according to claim 4, characterized in that: The angle between the tangent line of the outer circle at the major diameter of the part and the line connecting the center is 90°.

6. A rounding method for external spline tooth top profile according to claim 3, characterized in that: The rotation angle α of the forming column milling cutter 刀 for a 刀 =(a ce +90°)÷2-45°=(cos -1 (m*z*cos(α)÷D ce )+90°)÷2-45°.

7. A rounding method for external spline tooth top profile according to claim 1, characterized in that: In the step S3, when the forming column milling cutter is used for cutting, the cutting depth of the cutter does not exceed the required fillet R angle value.

8. A rounding method for external spline tooth top profile according to claim 1, characterized in that: In step S4, the α 件 The pressure angle α at the chamfer of the tooth tip ce And the diameter D of the measuring rod at the top arc of the tooth Re It turns out that the measuring rod diameter D Re The expression is In the above formula, D b is the base circle diameter, S min is the minimum value of the actual tooth thickness, D is the spline pitch circle diameter, and the α 件 The expression is In the above formula, D ce It is the diameter at the roller contact point, that is, the major diameter of the part.

9. A rounding method for external spline tooth top profile according to claim 1, characterized in that: In the step S4, when clamping the parts, a one-clamp-one-support method is adopted.

10. A rounding processing method for external spline tooth top profile according to claim 1, characterized in that: In step S4, a rolling rod is used to align the center of any tooth of the spline.

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