Method for grinding large-diameter internal circular-arc rack on numerical control forming gear grinding machine tool

Abstract

The application discloses a method for grinding a large-diameter internal circular-arc rack by using a numerical control forming gear grinding machine tool, which comprises the following steps: determining the rotation center of a machine tool rotary table, positioning a circular-arc rack to be processed on the machine tool rotary table through two positioning pins, and symmetrically arranging the two positioning pins on the two sides of the rotation center; and judging whether the center line of the circular-arc rack passes through the rotation center of the rotary table according to the height of the positioning pins and the rotation center. The method provided by the application can enable a small-specification machine tool with a small-rotation-diameter rotary table to process a large-diameter internal circular-arc rack, and the center line of the circular-arc rack can be adjusted to pass through the rotation center before grinding, so that the subsequent rotation and displacement are avoided, high-precision grinding is realized, space is saved, and cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of CNC forming grinding technology for gear racks, specifically to a method for grinding large-diameter internal arc gear racks using a CNC forming grinding machine. Background Technology

[0002] Currently, the grinding of gear racks is done by selecting the machine tool with the largest diameter of the gear rack. This results in larger machine tool sizes and higher processing costs for such workpieces. Summary of the Invention

[0003] The purpose of this invention is to provide a method for grinding large-diameter internal arc gear racks on a CNC forming gear grinding machine, so as to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides a method for grinding large-diameter internal arc gear racks on a CNC forming gear grinding machine, the method comprising the following steps:

[0005] S1. Determine the rotation center of the machine tool rotary table. The circular arc rack to be processed is positioned on the rotary table of the machine tool by two locating pins, which are symmetrically arranged on both sides of the rotation center.

[0006] S2. Based on the height of the locating pin and the center of rotation. Determine whether the centerline of the circular arc rack passes through the rotation center of the rotary table. ;

[0007] If so, do not adjust the position of the rotary table and proceed to step S3;

[0008] If not, adjust the position of the rotary table, obtain the position coordinates of the locating pin after adjustment and the rotation center of the rotary table, and proceed to step S3;

[0009] S3. Based on the coordinates of the rotation center and the coordinates of the two locating pins, calculate the theoretical center of the complete gear ring of the circular arc rack using trigonometric functions. ;

[0010] S4. During grinding, obtain the number of tooth grooves of the complete tooth ring of the arc rack. and the number of tooth grooves of the arc rack Based on the number of tooth grooves of the circular arc rack Calculate the tooth groove number;

[0011] S5. Based on the number of tooth grooves of the complete gear ring. Calculate the angle occupied by a single tooth groove Rotate the A-axis of the rotary table to the current tooth slot number based on the tooth slot number. Grinding;

[0012] S6. Divide the arc rack into several segments according to the tooth groove number, and treat each segment as the segment to be ground. Grind each segment in sequence according to the number.

[0013] S7. Determine whether the center of the arc of the current section to be ground is concentric with the rotation center of the rotary table. Based on the determination result, determine the rotation center and calculate the rotation center at any point on the section to be ground. The point after rotating around the center of rotation After rotating the A-axis of the rotary table according to the tooth groove number of the current grinding section, move the X-axis and Y-axis positions of the circular arc rack to the rotated point. Move the Y-axis to bring the rack close to the grinding gear, and grind it with the grinding wheel;

[0014] S8. Grind the sections to be ground according to the numbers in sequence until all sections to be ground are ground, thus completing the machining of each tooth groove.

[0015] Furthermore, the specific steps of step S2 are as follows:

[0016] S21. Use a dial indicator to calibrate the levelness of the two locating pins to within the preset range, and determine the position coordinates of the two locating pins in the machine tool using a probe. , ;

[0017] S22, Judgment Whether this is true or not depends on whether the heights of the two locating pins are consistent, and Is it valid?

[0018] If so, the centerline of the circular arc rack passes through the center of rotation;

[0019] If not, proceed to step S23 to adjust the A-axis and X-axis of the rotary table;

[0020] S23. Adjust the rotation angle of the rotary table A-axis. make And based on the position coordinates of the two locating pins in the machine tool , And the state of the rotary table after A-axis adjustment, calculate the coordinates of the center of the locating pin after the rotary table adjustment. The slewing center is adjusted according to its calculation. .

[0021] Furthermore, the calculation of the tooth groove number in step S4 is specifically as follows:

[0022] like If the number is even, then the left half of the rack has a total of There are 1 tooth groove, and the tooth groove number is 0~ The right half of the tooth groove numbering starts from: ;

[0023] like If the number is odd, then the left and right halves of the tooth grooves have respectively There are 1 tooth groove, numbered from left to right: 0~ -1.

[0024] Furthermore, in step S5 , .

[0025] Furthermore, step S7 specifically includes:

[0026] If the section to be ground is concentric with the rotation center of the rotary table, and the rotation center of the rotary table is taken as the rotation center, calculate the value of any point on the section to be ground. The point after rotating around the center of rotation ;

[0027] If the section to be ground is not concentric with the center of rotation, the theoretical center of the complete gear ring of the circular arc rack will be... Using the center of rotation, calculate any point on the section to be ground. The point reached after rotating around the center of rotation. .

[0028] Furthermore, the specific calculation formula in step S23 is as follows:

[0029]

[0030] In the above formula, The coordinates of the center of the positioning pin after A-axis adjustment. and These are the position coordinates of the locating pin in the machine tool. The rotation angle is the A-axis rotation angle.

[0031] Furthermore, any point on the section to be ground The point after rotating around the center of rotation The calculation formula is:

[0032]

[0033] In the above formula, This indicates the rotation angle of the section to be ground.

[0034] Beneficial effects: The method provided by this invention enables small-sized machine tools with small-diameter rotary tables to process large-diameter internal arc racks. Furthermore, by adjusting the center line of the arc rack to pass through the center of rotation before grinding, it avoids affecting subsequent rotation and displacement, achieving high-precision grinding, and saving space and reducing costs. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart of the method of the present invention;

[0037] Figure 2 This is a schematic diagram illustrating the principle of adjusting the position of the rotary table in this invention.

[0038] Figure 3 This is a schematic diagram of the processing scenario for the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] like Figures 1-3 As shown, this embodiment takes a grinding rack with an internal tooth radius of 2463.5mm as an example. If conventional machining methods are used, a 5000mm rotation space of the worktable is required. This invention uses a three-axis CNC linkage of the linear X-axis, linear Y-axis, and rotary worktable A-axis, with a worktable diameter of 400mm, which greatly saves machining space. The theoretical large-diameter internal arc rack trajectory is decomposed into several small arc segments according to a single tooth. The center line of each arc segment and the center line of the grinding wheel are located in the same plane. Each tooth is ground by a high-precision forming grinding wheel.

[0041] This invention provides a method for grinding large-diameter internal arc gear racks on a CNC forming gear grinding machine. This method utilizes a small-sized machine tool with a small-diameter rotary table to process large-diameter internal arc gear racks. The method includes the following steps:

[0042] Preparation phase:

[0043] S1. Determine the rotation center of the machine tool rotary table. The circular arc rack to be processed is positioned on the rotary table of the machine tool by two locating pins, which are symmetrically arranged on both sides of the rotation center. The rotary table and the fixture locating pins on the table are set on the fixture. The locating pins are interference-fitted with the circular arc rack. These are all existing devices and will not be described in detail here.

[0044] Specifically, the rotational center of the machine tool's rotary table is determined by using a fixed-radius ring on the machine tool and calibrating the ring's rotational and initial positions with a probe. In this embodiment, it is set as follows: The ring diameter used is 40MM. Using a ring with a fixed radius (usually referring to a standard ring gauge) to calibrate the rotation center is a classic and highly accurate method. In industrial applications, this method is often used for the calibration of the probe's own eccentricity and the measurement of the rotation axis center. It can also be extended to the calibration of the worktable's rotation center. This is existing technology and will not be elaborated here.

[0045] S2. Based on the height of the locating pin and the center of rotation. Determine whether the centerline of the circular arc rack passes through the rotation center of the rotary table. This allows us to determine whether the position of the rotary table needs to be adjusted to avoid affecting subsequent rotation and displacement.

[0046] If so, do not adjust the position of the rotary table and proceed to step S3;

[0047] If not, adjust the position of the rotary table, obtain the position coordinates of the locating pin after adjustment and the rotation center of the rotary table, so as to facilitate the subsequent calculation of the theoretical center of the complete gear ring of the circular arc rack, and proceed to step S3.

[0048] In this method, the movement of the X-axis and Y-axis is achieved by moving the X-axis slide and Y-axis slide on the rotary table. The A-axis is the rotation axis of the rotary table, which is a conventional setting in the prior art and will not be described in detail here.

[0049] Please refer to Figure 2 To achieve the adjustment in step S2, this embodiment further elaborates on the following steps. In the figure, D1 is the diameter of the rotary table, D2 is the radius of the complete arc of the rack where the two locating pins are located, and D3 is the diameter of the locating pin. In this embodiment, the center position of the locating pin is used for calculation. , These are all the center positions of the locating pins; actual processing can be adjusted according to the actual situation.

[0050] S21. Use a dial indicator to calibrate the levelness of the two locating pins to within the preset range, and determine the position coordinates of the two locating pins in the machine tool using a probe. , In this implementation, the high point levelness of the positioning pin is set within 0.01mm;

[0051] S22, Judgment Whether this is true or not depends on whether the heights of the two locating pins are consistent, and Is it valid?

[0052] If so, the centerline of the circular arc rack passes through the center of rotation;

[0053] If not, proceed to step S23 to adjust the A-axis and X-axis of the rotary table;

[0054] S23. Adjust the rotation angle of the rotary table A-axis. make And based on the position coordinates of the two locating pins in the machine tool , And the state of the rotary table after A-axis adjustment, calculate the coordinates of the center of the locating pin after the rotary table adjustment. The slewing center is adjusted according to its calculation. :

[0055]

[0056] In the above formula, These represent the coordinates of the center of the positioning pin after the rotary table has been adjusted.

[0057] S3. Based on the coordinates of the rotation center and the coordinates of the two locating pins, calculate the theoretical center of the complete gear ring of the circular arc rack using trigonometric functions. ;

[0058] Grinding stage:

[0059] S4. In this embodiment, the arc-shaped rack is a partial arc-shaped rack cut from a complete gear ring. During grinding, the number of tooth grooves of the complete gear ring is obtained. and the number of tooth grooves of the arc rack Based on the number of tooth grooves of the circular arc rack Calculate the tooth groove number. In this embodiment, the machining sequence of the arc rack during operation is from the leftmost tooth groove to the rightmost tooth groove.

[0060] Since the circular arc rack is symmetrical about the rotary table, if If the number is even, then the left half of the rack has a total of There are 1 tooth groove, and the tooth groove number is 0~ The right half of the tooth groove numbering starts from: ;

[0061] like If the number is odd, then the left and right halves of the tooth grooves have respectively There are 1 tooth groove, numbered from left to right: 0~ -1.

[0062] S5. Based on the number of tooth grooves of the complete gear ring. Calculate the angle occupied by a single tooth groove Rotate the A-axis of the rotary table to the current tooth slot number based on the tooth slot number. Grinding is performed, among which... , ;

[0063] S6. Divide the arc rack into several segments according to the tooth groove number, and treat each segment as the segment to be ground. Grind each segment in sequence according to the number.

[0064] S7. Determine whether the center of the arc of the current section to be ground is concentric with the rotation center of the rotary table. Based on the determination result, determine the rotation center and calculate the rotation center at any point on the section to be ground. The point after rotating around the center of rotation After rotating the A-axis of the rotary table according to the tooth groove number of the current grinding section, wait until the center line of the teeth in the grinding section is parallel to the center line of the grinding wheel, and then move the X-axis and Y-axis positions of the arc rack to the rotated position. Moving the X-axis can make the center line of the inner teeth of the rack to be ground coincide with the center line of the grinding wheel. Moving the Y-axis brings the rack closer to the grinding gear, and the grinding wheel performs grinding, simulating the trajectory of the entire gear ring around the theoretical rotation center.

[0065] Specifically: if the section to be ground is concentric with the rotation center of the rotary table, the rotation center of the rotary table is taken as the rotation center; if the section to be ground is not concentric with the rotation center, the theoretical center of the complete gear ring of the circular arc rack is taken as the rotation center. Using the center of rotation, calculate any point on the section to be ground. The point reached after rotating around the center of rotation. The calculation formula is:

[0066]

[0067] In the above formula, This indicates the rotation angle of the section to be ground.

[0068] S8. Grind each numbered section in sequence until all numbered sections have been ground, completing the machining of each tooth groove. The entire process is divided into rough grinding and fine grinding. Rough grinding uses a CBN grinding wheel to quickly process to a certain size, while fine grinding is responsible for the final size, shaping, and ideal waviness.

[0069] like Figure 3 As shown, the above method is used for processing Figure 3 When grinding a single internal tooth, rotate the rotary table to make the center line of the internal tooth to be ground parallel to the center line of the grinding wheel. Then move the X-axis slide to make the center line of the internal tooth of the rack to be ground coincide with the center line of the grinding wheel. Move the Y-axis slide to move the rack to be ground to the grinding wheel, and then the subsequent grinding work can be carried out.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0071] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for grinding large-diameter internal arc gear racks on a CNC forming gear grinding machine, characterized in that, Includes the following steps: S1. Determine the rotation center of the machine tool rotary table. The circular arc rack to be processed is positioned on the rotary table of the machine tool by two locating pins, which are symmetrically arranged on both sides of the rotation center. S2. Based on the height of the locating pin and the center of rotation. Determine whether the centerline of the circular arc rack passes through the rotation center of the rotary table. ; If so, do not adjust the position of the rotary table and proceed to step S3; If not, adjust the position of the rotary table, obtain the position coordinates of the locating pin after adjustment and the rotation center of the rotary table, and proceed to step S3; S3. Based on the coordinates of the rotation center and the coordinates of the two locating pins, calculate the theoretical center of the complete gear ring of the circular arc rack using trigonometric functions. ; S4. During grinding, obtain the number of tooth grooves of the complete tooth ring of the arc rack. and the number of tooth grooves of the arc rack Based on the number of tooth grooves of the circular arc rack Calculate the tooth groove number; S5. Based on the number of tooth grooves of the complete gear ring. Calculate the angle occupied by a single tooth groove Rotate the A-axis of the rotary table to the current tooth slot number based on the tooth slot number. Grinding; S6. Divide the arc rack into several segments according to the tooth groove number, and treat each segment as the segment to be ground. Grind each segment in sequence according to the number. S7. Determine whether the center of the arc of the current section to be ground is concentric with the rotation center of the rotary table. Based on the determination result, determine the rotation center and calculate the rotation center at any point on the section to be ground. The point after rotating around the center of rotation After rotating the A-axis of the rotary table according to the tooth groove number of the current grinding section, move the X-axis and Y-axis positions of the circular arc rack to the rotated point. Move the Y-axis to bring the rack close to the grinding gear, and grind it with the grinding wheel; S8. Grind the sections to be ground according to the numbers in sequence until all sections to be ground are ground, thus completing the machining of each tooth groove.

2. The method according to claim 1, characterized in that: The specific steps of step S2 are as follows: S21. Use a dial indicator to calibrate the levelness of the two locating pins to within the preset range, and determine the position coordinates of the two locating pins in the machine tool using a probe. , ; S22, Judgment Whether this is true or not depends on whether the heights of the two locating pins are consistent, and Is it valid? If so, the centerline of the circular arc rack passes through the center of rotation; If not, proceed to step S23 to adjust the A-axis and X-axis of the rotary table; S23. Adjust the rotation angle of the rotary table A-axis. make And based on the position coordinates of the two locating pins in the machine tool , And the state of the rotary table after A-axis adjustment, calculate the coordinates of the center of the locating pin after the rotary table adjustment. The slewing center is adjusted according to its calculation. .

3. The method according to claim 1, characterized in that: The calculation of the tooth groove number in step S4 is as follows: like If the number is even, then the left half of the rack has a total of There are 1 tooth groove, and the tooth groove number is 0~ The right half of the tooth groove numbering starts from: ; like If the number is odd, then the left and right halves of the tooth grooves have respectively There are 1 tooth groove, numbered from left to right: 0~ -1.

4. The method according to claim 1, characterized in that: In step S5 , .

5. The method according to claim 1, characterized in that: Step S7 specifically involves: If the section to be ground is concentric with the rotation center of the rotary table, and the rotation center of the rotary table is taken as the rotation center, calculate the value of any point on the section to be ground. The point after rotating around the center of rotation ; If the section to be ground is not concentric with the center of rotation, the theoretical center of the complete gear ring of the circular arc rack will be... Using the center of rotation, calculate any point on the section to be ground. The point reached after rotating around the center of rotation. .

6. The method according to claim 2, characterized in that: The specific calculation formula in step S23 is as follows: ， In the above formula, The coordinates of the center of the positioning pin after A-axis adjustment. and These are the position coordinates of the locating pin in the machine tool. The rotation angle is the A-axis rotation angle.

7. The method according to claim 5, characterized in that: Any point on the section to be ground The point after rotating around the center of rotation The calculation formula is: ， In the above formula, This indicates the rotation angle of the section to be ground.

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