A bevel gear hobbing machine tool

Abstract

This invention relates to the field of gear manufacturing technology and discloses a bevel gear hobbing machine tool, including a machine base, a hobbing cutter, a rotary table, and a control unit. A three-axis module is mounted on the machine base, and the rotary table is rotatably mounted on the upper surface of the machine base. A first geared motor is installed inside the machine base to drive the rotary table to rotate according to the machining angle. A second geared motor is fixedly mounted on the rotary table, and the gear to be processed is detachably clamped and mounted on the rotating end of the second geared motor. The hobbing machine tool proposed in this invention, by setting up a rotary table, uses the rotation of the rotary table to adjust the angle of the gear to be processed, making the conical profile of the gear parallel to the X-axis of the three-axis module. The hobbing cutter reciprocates along the X-axis to cut the gear. When the taper of the gear to be processed is different, the rotation angle of the rotary table can be changed to meet the production needs of processing gears with different taper angles.

Description

Technical Field

[0001] This invention relates to the field of gear manufacturing technology, and in particular to a bevel gear hobbing machine. Background Technology

[0002] Gear machining is a key process in the field of mechanical manufacturing. Its methods can be categorized into various technical paths depending on the gear type (spur, spiral, etc.) and machining accuracy requirements. For example, patent document CN104985260B discloses a continuous hobbing method for straight bevel gears. This method is based on an approximately straight internal cycloid, where the cutter head rotates at a speed of ωt, and the gear rotates at a speed of ωg. The relative motion between the gear and the cutter is equivalent to a pure rolling meshing motion of the cutter and gear. When the rolling radius of the cutter is consistent with the reference radius and equal to half the rolling radius of the gear, the trajectory formed by the cutter tip on the gear is approximately a straight line, thus making it suitable for continuous hobbing of straight bevel gears.

[0003] The taper of bevel gears varies mainly due to design functions, processing technology, and application scenarios. During the bevel gear hobbing process, when machining gears with different tapers, it is necessary to adjust the cutting path of the machine tool, which is very troublesome in practice. As a result, existing gear hobbing machine tools have the defect of being inconvenient to process gears with different tapers, which urgently needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing gear hobbing machine tools, which are inconvenient for processing gears with different bevels, and to propose a bevel gear hobbing machine tool.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A bevel gear hobbing machine tool includes a machine base, a hobbing cutter, a rotary table, and a control unit. A three-axis module is mounted on the machine base. The three-axis module includes an X-axis module, a Y-axis module, a Z-axis module, and a movable platform that are orthogonal to each other. The three-axis module drives the movable platform to translate in the coordinate system XYZ. A cutting drive motor is fixedly mounted on the movable platform, and the hobbing cutter is fixedly mounted on the rotating end of the cutting drive motor. The rotary table is rotatably mounted on the upper surface of the machine base, and a first reduction motor is installed inside the machine base to drive the rotary table to rotate according to the processing angle; A second reduction motor is fixedly installed on the rotating platform, and the gear to be processed is detachably clamped and installed on the rotating end of the second reduction motor. The upper surface of the machine base is provided with a displacement detection mechanism, and a reference gear is installed on the displacement detection mechanism. When the rotating table rotates to the first angle, the gear to be processed is cut by the reciprocating translation of the hobbing cutter. When the rotating table rotates to the second angle, the gear to be processed meshes with the reference gear and is driven by it. The displacement L2 of the reference gear is detected by the displacement detection mechanism. The control unit is electrically connected to the first reduction motor and the displacement detection mechanism, and is configured to: control the rotary table to be positioned and locked to a first angle during machining, and to be positioned to a second angle during detection; control the three-axis module and the cutting drive motor to perform rolling machining; collect the displacement L2 output by the displacement detection mechanism in the detection posture; calculate the tool compensation amount based on the geometric projection relationship of the first angle, and write the tool compensation amount into the tool compensation parameters of the CNC system; execute in the order of "roughing-detection-compensation-finishing" to achieve adaptive compensation for tool wear and machining deviation; when the taper of the gear to be machined is different, the rotation angle of the rotary table can be changed to meet the production needs of machining gears with different taper.

[0006] Preferably, the displacement detection mechanism includes a detection box, a movable seat is slidably installed inside the detection box, a displacement sensor is fixedly installed inside the detection box, the movable end of the displacement sensor is fixedly connected to the movable seat, and a reference gear is assembled with the movable seat. A rotating shaft is rotatably mounted inside the movable seat. The axis of the rotating shaft is coplanar and parallel to the axis of the second geared motor. The end of the rotating shaft extends to the outside of the detection box. The reference gear is fixedly mounted on the end of the rotating shaft by a nut. A guide rod is fixedly mounted inside the detection box. The movable seat is slidably mounted on the surface of the guide rod. A return spring is sleeved on the surface of the guide rod. Under the action of the return spring, the return spring pushes the movable seat to a position away from the displacement sensor. Based on the measured displacement, the tool compensation parameters of the machine tool are modified to complete the final finishing process. This avoids the increase in error due to tool wear, thereby achieving an adaptive compensation machining effect and improving machining accuracy.

[0007] Preferably, when the rotary table rotates to the first angle, the angle between the axis of the second reduction motor and the X coordinate axis is α, 0°≤α≤90°, and the size of α is determined by the taper size of the gear to be processed. The rotation angle of the rotary table 3 is α.

[0008] Preferably, when the rotary table rotates to the second angle, the axis of the second reduction motor is parallel to the X-axis, and the gear to be processed is meshed with the reference gear. The rotary table can be repeatedly positioned so that multiple error measurements can be performed as needed.

[0009] Preferably, the Y-axis module includes a first guide rail assembly fixedly mounted on the base, a first lead screw rotatably mounted inside the first guide rail assembly, and a first servo motor fixedly mounted at the end of the first guide rail assembly, thereby driving the first lead screw to rotate. The X-axis module includes a second guide rail assembly that is slidably mounted on a first guide rail assembly. A second lead screw is rotatably mounted inside the second guide rail assembly and is threadedly connected to the first guide rail assembly. A second servo motor is fixedly mounted at the end of the second guide rail assembly, and the second lead screw is driven to rotate by the second servo motor. The Z-axis module includes a third guide rail assembly that is slidably mounted on the second guide rail assembly. A third lead screw is rotatably mounted inside the third guide rail assembly. The movable platform is slidably mounted on the third guide rail assembly, and the third lead screw is threadedly connected to the movable platform. A third servo motor is fixedly mounted at the end of the third guide rail assembly. The third servo motor drives the third lead screw to rotate, thereby enabling the three-axis module to drive the movable platform to translate in the XYZ coordinate system.

[0010] The present invention has the following beneficial effects: 1. The hobbing machine tool proposed in this invention uses a rotating table to adjust the angle of the gear to be processed, so that the conical profile of the gear to be processed is parallel to the X-axis of the three-axis module. The hobbing cutter moves back and forth along the X-axis to cut the gear to be processed. When the taper of the gear to be processed is different, the rotation angle of the rotating table can be changed to meet the production needs of processing gears with different taper.

[0011] 2. The hobbing machine tool proposed in this invention, by setting up a combination of a rotating table and a displacement detection mechanism, allows a certain allowance to be reserved before the gear to be machined is finished. When the rotating table rotates to the second angle, the gear to be machined meshes with the reference gear. The displacement of the reference gear is detected by the displacement detection mechanism. Using this displacement as reference data, the accurate value of the reserved allowance can be truly reflected. Based on the measured reference data, the tool compensation parameters of the machine tool are modified to complete the final finishing, avoiding the increase of error due to tool wear, thereby achieving an adaptive compensation machining effect and improving machining accuracy.

[0012] 3. The hobbing machine tool proposed in this invention, by installing a driven rotatable reference gear on the displacement detection mechanism, when inspecting the finishing allowance of the gear to be processed, the gear to be processed meshes with the reference gear, and through the drive of the second reduction motor, the gear to be processed and the reference gear can be rotated. The displacement detection mechanism can detect the allowance of each tooth wall of the gear to be processed, providing compensation data for compensation processing, so as to ensure the machining accuracy of the gear to be processed. When the difference in the allowance of each tooth wall is large, it indicates that the hobbing tool is severely worn. Based on this feedback signal, the control unit issues a warning signal to remind the operator to replace the hobbing tool in time. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of the rolling cutter proposed in this invention. Figure 1 ; Figure 2 This is a three-dimensional structural diagram of the rolling cutter proposed in this invention. Figure 2 ; Figure 3 This is a partial top view of the machine base structure proposed in this invention (processing posture); Figure 4 This is a partial top view of the base structure proposed in this invention (for attitude detection). Figure 5 This is a partial top view of the machine base structure proposed in this invention (loading and unloading posture). Figure 6 This is a top-section structural diagram of the detection box proposed in this invention; Figure 7 This is a schematic diagram of the contact between the gear to be processed and the reference gear proposed in this invention; Figure 8 This is a schematic diagram of a hobbing tool cutting the gear to be machined.

[0014] In the diagram: 1. Machine base; 2. Roll cutting tool; 3. Rotary table; 4. Movable platform; 5. Cutting drive motor; 6. First geared motor; 7. Second geared motor; 8. Gear to be processed; 9. Reference gear; 10. Detection box; 11. Movable seat; 12. Displacement sensor; 13. Rotating shaft; 14. Guide rod; 15. Return spring; 16. First guide rail assembly; 17. First lead screw; 18. First servo motor; 19. Second guide rail assembly; 20. Second lead screw; 21. Second servo motor; 22. Third guide rail assembly; 23. Third lead screw; 24. Third servo motor. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0016] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0017] Reference Figures 1-8A bevel gear hobbing machine tool includes a machine base 1, a hobbing cutter 2, a rotary table 3, and a control unit. A three-axis module is mounted on the machine base 1. The three-axis module includes an X-axis module, a Y-axis module, a Z-axis module, and a movable platform 4, which are orthogonal to each other. The three-axis module drives the movable platform 4 to translate in the coordinate system XYZ. A cutting drive motor 5 is fixedly mounted on the movable platform 4. The hobbing cutter 2 is fixedly mounted on the rotating end of the cutting drive motor 5. Specifically, the Y-axis module includes a first guide rail assembly 16 fixedly mounted on the base 1, a first lead screw 17 rotatably mounted inside the first guide rail assembly 16, and a first servo motor 18 fixedly mounted at the end of the first guide rail assembly 16, which drives the first lead screw 17 to rotate. The X-axis module includes a second guide rail assembly 19 that is slidably mounted on a first guide rail assembly 16. A second lead screw 20 is rotatably mounted inside the second guide rail assembly 19 and is threadedly connected to the first guide rail assembly 16. A second servo motor 21 is fixedly mounted at the end of the second guide rail assembly 19, and the second lead screw 20 is driven to rotate by the second servo motor 21. The Z-axis module includes a third guide rail assembly 22 that is slidably mounted on the second guide rail assembly 19. A third lead screw 23 is rotatably mounted inside the third guide rail assembly 22. A movable platform 4 is slidably mounted on the third guide rail assembly 22, and the third lead screw 23 is threadedly connected to the movable platform 4. A third servo motor 24 is fixedly mounted at the end of the third guide rail assembly 22, and the third lead screw 23 is driven to rotate by the third servo motor 24.

[0018] like Figure 1 As shown, controlled by the control unit, the first servo motor 18 rotates in both directions, driving the movable platform 4 to reciprocate along the Y-axis via the transmission of the first lead screw 17; the second servo motor 21 rotates in both directions, driving the movable platform 4 to reciprocate along the X-axis via the transmission of the second lead screw 20; the third servo motor 24 rotates in both directions, driving the movable platform 4 to reciprocate along the Z-axis via the transmission of the third lead screw 23; and the rotation of the cutting drive motor 5 drives the rotation of the hobbing cutter 2.

[0019] The rotating table 3 is rotatably mounted on the upper surface of the machine base 1. The machine base 1 contains a first reduction motor 6 that drives the rotating table 3 to rotate according to the machining angle. Figure 2 As shown, a worm is fixedly installed on the rotating end of the first geared motor 6, and a worm wheel is fixedly installed on the bottom of the rotating table 3. The worm and the worm wheel mesh and drive each other. Under the driving action of the first geared motor 6, the rotating table 3 can maintain any rotation angle. A second reduction motor 7 is fixedly mounted on the rotary table 3. The gear 8 to be processed is detachably clamped and mounted on the rotating end of the second reduction motor 7. (Refer to...) Figure 3 , Figure 4 , Figure 5By rotating the rotary table 3, the orientation of the gear 8 to be processed is changed, such as... Figure 5 As shown, the gear 8 to be processed faces the operator, making it easier to disassemble and assemble the gear 8.

[0020] In this embodiment, a displacement detection mechanism is provided on the upper surface of the base 1. A reference gear 9 is installed on the displacement detection mechanism. The module, number of teeth, pitch cone angle, and tooth direction of the reference gear 9 are matched with those of the gear 8 to be processed. When the rotating table 3 rotates to the first angle, the gear 8 to be processed is cut by the reciprocating translation of the hobbing cutter 2. When the rotating table 3 rotates to the second angle, the gear 8 to be processed meshes with the reference gear 9. The displacement L2 of the reference gear 9 is detected by the displacement detection mechanism.

[0021] like Figure 6 As shown, the displacement detection mechanism includes a detection box 10, a movable seat 11 is slidably installed inside the detection box 10, a displacement sensor 12 is fixedly installed inside the detection box 10, the movable end of the displacement sensor 12 is fixedly connected to the movable seat 11, and the reference gear 9 is assembled with the movable seat 11.

[0022] A rotating shaft 13 is rotatably mounted inside the movable seat 11. The axis of the rotating shaft 13 is coplanar and parallel to the axis of the second reduction motor 7. The end of the rotating shaft 13 extends to the outside of the detection box 10. The reference gear 9 is fixedly mounted on the end of the rotating shaft 13 by a nut.

[0023] A guide rod 14 is fixedly installed inside the detection box 10. The movable seat 11 is slidably installed on the surface of the guide rod 14. A reset spring 15 is sleeved on the surface of the guide rod 14. Under the action of the reset spring 15, the reset spring 15 pushes the movable seat 11 to a position away from the displacement sensor 12.

[0024] In this embodiment, as Figure 3 As shown, when the rotary table 3 rotates to the first angle, the angle between the axis of the second reduction motor 7 and the X coordinate axis is α, where 0°≤a≤90°. The size of α is determined by the taper of the gear 8 to be processed. The hobbing cutter 2 moves back and forth along the X coordinate axis to cut the gear 8 to be processed. When the taper of the gear 8 to be processed is different, the rotation angle α of the rotary table 3 can be changed to meet the production requirements of processing gears with different tapers. It should be noted that wear or tooth breakage can occur during the cutting process of the hobbing tool 2, resulting in a decrease in the accuracy of gear machining.

[0025] refer to Figure 4 When the rotating table 3 rotates to the second angle, the axis of the second reduction motor 7 is parallel to the X-axis, and the gear 8 to be processed is in meshing contact with the reference gear 9. At this time, if... Figure 7As shown, assuming the allowance after rough machining of the gear 8 is L1 (in reality, the allowance refers to the thickness of the gear 8 in the Y-axis direction at a specific machining angle; for ease of understanding below, it is represented by L1 in the figure), when the axis of the second reduction motor 7 is parallel to the X-axis, the return spring 15 is compressed, and the reference gear 9 moves along... Figure 7 The displacement sensor 12 detects the displacement of the reference gear 9 as L2 when it moves in the direction indicated by the middle arrow. Since the displacement of the reference gear 9 is generated by the pressure of the gear 8 to be processed, L1 and L2 represent the straight distance in the same direction, L1=L2, and thus the allowance is detected by the displacement sensor 12. refer to Figure 8 The allowance after rough machining of gear 8 is L1, which is a measured value. When the hobbing tool 2 wears, the theoretical value of the allowance will be smaller than L1. If the theoretical value of the allowance is used directly for finishing, the error will be relatively large. To compensate for the wear error, the compensation increase of the hobbing tool 2 is Lx, where Lx = sin(90° - a) * L1. This is a geometric calculation; please refer to the appendix. Figure 8 This will not be elaborated here, but the increase in the movement of the hobbing cutter 2 along the Y-axis is Lx.

[0026] The control unit, electrically connected to the first reduction motor 6 and the displacement detection mechanism, is configured to: control the rotary table 3 to position and lock it to a first angle during processing. Figure 3 As shown, the device is positioned at the second angle during posture detection; the three-axis module and cutting drive motor 5 are controlled to perform rolling cutting; as shown... Figure 4 As shown, the displacement L2 output by the displacement detection mechanism is collected under the detection posture; the tool compensation amount Lx is calculated based on the geometric projection relationship of the first angle, and the tool compensation amount Lx is written into the tool compensation parameters of the CNC system; the process is executed in the order of "roughing-detection-compensation-finishing" to achieve adaptive compensation for tool wear and machining deviation.

[0027] The hobbing machine tool proposed in this invention, by setting up a combination of a rotating table 3 and a displacement detection mechanism, allows a certain allowance to be reserved before the gear 8 to be machined is finished. When the rotating table 3 rotates to the second angle, the gear 8 to be machined meshes with the reference gear 9. The displacement of the reference gear 9 is detected by the displacement detection mechanism. Using this displacement as reference data, the accurate value of the reserved allowance can be truly reflected. Based on the measured reference data, the tool compensation parameters of the machine tool are modified to complete the final finishing, avoiding the increase of error due to tool wear, thereby achieving an adaptive compensation machining effect and improving machining accuracy.

[0028] By installing a rotatable reference gear 9 on the displacement detection mechanism, when inspecting the finishing allowance of the gear 8 to be processed, the gear 8 to be processed meshes with the reference gear 9, and is driven by the second reduction motor 7 to rotate the gear 8 to be processed and the reference gear 9. The displacement detection mechanism can detect the allowance of each tooth wall of the gear 8 to be processed, providing compensation data for compensation processing, so as to ensure the processing accuracy of the gear 8 to be processed. When the difference in the allowance of each tooth wall is large, it indicates that the hobbing tool 2 is severely worn. Based on this feedback signal, the control unit issues a warning signal to remind the operator to replace the hobbing tool 2 in time.

[0029] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A bevel gear hobbing machine tool, comprising a machine base (1), a hobbing cutter (2), a rotary table (3), and a control unit, characterized in that: The base (1) is equipped with a three-axis module, which includes an X-axis module, a Y-axis module, a Z-axis module and a movable platform (4) that are orthogonal to each other. The three-axis module drives the movable platform (4) to translate in the coordinate system XYZ. A cutting drive motor (5) is fixedly installed on the movable platform (4), and a rolling cutter (2) is fixedly installed on the rotating end of the cutting drive motor (5). The rotating table (3) is rotatably mounted on the upper plane of the machine base (1), and a first reduction motor (6) is provided inside the machine base (1) to drive the rotating table (3) to rotate according to the processing angle. The second geared motor (7) is fixedly installed on the rotating table (3), and the gear (8) to be processed is detachably clamped and installed on the rotating end of the second geared motor (7). The upper surface of the base (1) is provided with a displacement detection mechanism, and a reference gear (9) is installed on the displacement detection mechanism. When the rotating table (3) rotates to the first angle, the gear to be processed (8) is cut by the reciprocating translation of the hobbing cutter (2). When the rotating table (3) rotates to the second angle, the gear to be processed (8) meshes with the reference gear (9) and the displacement L2 of the reference gear (9) is detected by the displacement detection mechanism. The control unit is electrically connected to the first reduction motor (6) and the displacement detection mechanism, and is configured to: control the rotary table (3) to be positioned and locked to the first angle in the machining posture, and to be positioned to the second angle in the detection posture; control the three-axis module and the cutting drive motor (5) to perform rolling cutting; collect the displacement L2 output by the displacement detection mechanism in the detection posture; calculate the tool compensation amount according to the geometric projection relationship of the first angle, and write the tool compensation amount into the tool compensation parameters of the CNC system; execute in the order of "roughing-detection-compensation-finishing" to achieve adaptive compensation for tool wear and machining deviation.

2. The bevel gear hobbing machine tool according to claim 1, characterized in that: The displacement detection mechanism includes a detection box (10), a movable seat (11) is slidably installed inside the detection box (10), a displacement sensor (12) is fixedly installed inside the detection box (10), the movable end of the displacement sensor (12) is fixedly connected to the movable seat (11), and the reference gear (9) is assembled with the movable seat (11).

3. A bevel gear hobbing machine tool according to claim 2, characterized in that: A rotating shaft (13) is rotatably installed inside the movable seat (11). The axis of the rotating shaft (13) is coplanar and parallel with the axis of the second gear motor (7). The end of the rotating shaft (13) extends to the outside of the detection box (10). The reference gear (9) is fixedly installed at the end of the rotating shaft (13) by a nut.

4. A bevel gear hobbing machine tool according to claim 3, characterized in that: A guide rod (14) is fixedly installed inside the detection box (10). The movable seat (11) is slidably installed on the surface of the guide rod (14). A reset spring (15) is sleeved on the surface of the guide rod (14). Under the action of the reset spring (15), the reset spring (15) pushes the movable seat (11) to move away from the displacement sensor (12).

5. A bevel gear hobbing machine tool according to claim 1, characterized in that: When the rotating platform (3) rotates to the first angle, the angle between the axis of the second reduction motor (7) and the X coordinate axis is a, 0°≤a≤90°.

6. A bevel gear hobbing machine tool according to claim 1, characterized in that: When the rotating table (3) rotates to the second angle, the axis of the second reduction motor (7) is parallel to the X coordinate axis, and the gear to be processed (8) meshes with the reference gear (9).

7. A bevel gear hobbing machine tool according to any one of claims 1-6, characterized in that: The Y-axis module includes a first guide rail assembly (16) fixedly mounted on a base (1), a first lead screw (17) rotatably mounted inside the first guide rail assembly (16), and a first servo motor (18) fixedly mounted at the end of the first guide rail assembly (16), which drives the first lead screw (17) to rotate.

8. A bevel gear hobbing machine tool according to claim 7, characterized in that: The X-axis module includes a second guide rail assembly (19) that is slidably mounted on the first guide rail assembly (16). A second lead screw (20) is rotatably mounted inside the second guide rail assembly (19), and the second lead screw (20) is threadedly connected to the first guide rail assembly (16). A second servo motor (21) is fixedly mounted at the end of the second guide rail assembly (19), and the second lead screw (20) is driven to rotate by the second servo motor (21).

9. A bevel gear hobbing machine tool according to claim 8, characterized in that: The Z-axis module includes a third guide rail assembly (22) that is slidably mounted on the second guide rail assembly (19). A third lead screw (23) is rotatably mounted inside the third guide rail assembly (22). A movable platform (4) is slidably mounted on the third guide rail assembly (22), and the third lead screw (23) is threadedly connected to the movable platform (4). A third servo motor (24) is fixedly mounted at the end of the third guide rail assembly (22), and the third lead screw (23) is driven to rotate by the third servo motor (24).

Images