Numerical control equipment capable of continuously, ultrasonically and compositely rolling gear and control method

Abstract

The invention discloses numerical control equipment capable of continuously performing ultrasonic composite rolling on a gear and a control method, and relates to the technical field of gear machining, the numerical control equipment comprises a multi-axis moving platform, a workpiece shaft, a driving shaft, a rolling gear and an ultrasonic vibration assembly, the multi-axis moving platform has driving strokes of an X axis, a Y axis, a Z axis and a B axis, and the B axis is in the direction rotating around the Y axis; the end part of the workpiece shaft is used for clamping a gear to be machined; the driving shaft is parallel to the workpiece shaft, the driving shaft can be driven to rotate around the axis of the driving shaft, and the driving shaft is connected with the multi-shaft moving platform; the rolling gear is arranged at the end of the driving shaft and used for being meshed with a to-be-machined gear. The ultrasonic vibration assembly is connected with the rolling gear and applies ultrasonic vibration to the rolling gear. According to the numerical control equipment capable of continuously, ultrasonically and compositely rolling the gear and the control method, on the premise that the same modulus and pressure angle are met, ultrasonic rolling can be conducted on gears of different gear systems, and the ultrasonic rolling performance and efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gear processing, and particularly relates to a numerical control device and a control method for continuously ultrasonic composite rolling gears. Background Art

[0002] As a composite machining method that combines ultrasonic vibration and transmission rolling, the ultrasonic-assisted rolling technology is of great significance in improving the mechanical properties of the metal surface layer and extending the fatigue life of the machined parts. In the application of gear processing, ultrasonic-assisted rolling gears can improve the surface finish of the tooth surface, enhance the tooth surface hardness and wear resistance, thereby improving the fatigue life of the gears.

[0003] At the present stage, the existing ultrasonic-assisted rolling gear equipment can only perform ultrasonic-assisted rolling on complete meshing gears of the same type and the same tooth system, and can only roll one gear at a time, unable to continuously roll gears, with low efficiency. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present invention provides a numerical control device for continuously ultrasonic composite rolling gears, which can perform ultrasonic rolling on gears of different tooth systems on the premise of meeting the same module and pressure angle, improving the ultrasonic rolling performance and efficiency.

[0005] The present invention also provides a control method for continuously ultrasonic composite rolling gears.

[0006] According to the numerical control device for continuously ultrasonic composite rolling gears of the first aspect embodiment of the present invention, it includes a multi-axis moving platform, and the multi-axis moving platform has driving strokes of the X-axis, Y-axis, Z-axis and B-axis, wherein the X-axis, Y-axis and Z-axis are perpendicular to each other in pairs, and the B-axis is the direction of rotation around the Y-axis; A workpiece shaft, the workpiece shaft is parallel to the X-axis, and the end of the workpiece shaft is used for clamping the gear to be processed; A driving shaft, the driving shaft is parallel to the workpiece shaft, the driving shaft can be driven to rotate around the axis of the driving shaft, and the driving shaft is connected to the multi-axis moving platform; A rolling gear, the rolling gear is arranged at the end of the driving shaft, and the rolling gear is used for meshing with the gear to be processed; An ultrasonic vibration assembly, the ultrasonic vibration assembly is connected to the rolling gear and applies ultrasonic vibration to the rolling gear.

[0007] The numerical control equipment for continuously ultrasonic composite rolling gears according to the embodiments of the present invention has at least the following beneficial effects: The multi-axis moving platform drives the driving shaft, enabling the rolling gear on the driving shaft to move along the Z-axis for vertical adjustment to ensure that the rolling gear and the gear to be processed are at the same height; the rolling gear can move along the X-axis for axial feeding, that is, move along the axis of the gear to be processed, achieving full tooth width coverage; the rolling gear can move along the Y-axis to control the feeding of the rolling gear towards the tooth surface of the gear to be processed, adjusting or applying the rolling pressure; the rolling gear can rotate on the B-axis to adapt to the helical contact angle; the multi-axis moving platform can drive the rolling gear to move in space, enabling the processing curve of the rolling gear to follow the tooth surface contour of the gear to be processed in real time; the driving shaft rotates around its own axis, and the rolling gear and the gear to be processed maintain meshing transmission, enabling continuous rolling of the gear to be processed, improving the ultrasonic rolling performance and efficiency.

[0008] According to some embodiments of the present invention, the ultrasonic vibration assembly includes a transducer and a horn. The horn is arranged at the end of the driving shaft. The horn is coaxially arranged with the driving shaft, and the transducer is connected to the horn.

[0009] According to some embodiments of the present invention, the horn and the driving shaft are of an integral structure. The driving shaft is provided with a horn section. The horn section includes a first cylindrical section, a first curve transition section, and a second cylindrical section. The diameter of the first cylindrical section is larger than that of the second cylindrical section. The first curve transition section smoothly connects the first cylindrical section and the second cylindrical section. The second cylindrical section extends axially along the driving shaft to the end of the driving shaft. The first cylindrical section, the first curve transition section, and the second cylindrical section together form the horn, and the rolling gear is connected to the second cylindrical section.

[0010] According to some embodiments of the present invention, both ends of the workpiece shaft are used to clamp the gear to be processed. The driving shaft is further provided with a third cylindrical section. The third cylindrical section is located on the opposite side of the second cylindrical section. The diameter of the third cylindrical section is smaller than that of the first cylindrical section. There is a second curve transition section between the third cylindrical section and the first cylindrical section, and a rolling gear is also connected to the third cylindrical section.

[0011] According to some embodiments of the present invention, the generatrix of the first curve transition section and the generatrix of the second curve transition section are both Gaussian curves.

[0012] According to some embodiments of the present invention, the length of the driving shaft is L. The lengths of the second cylindrical section and the third cylindrical section are both 0.1L, and the diameters are both 0.35R. The length of the first cylindrical section is 0.2L, and the diameter is R. The axial lengths of the first curve transition section and the second curve transition section are both 0.3L. The Gaussian curve function satisfies the following formula: ; ; Wherein, K is the attenuation ratio coefficient, and X is the distance in the X-axis direction.

[0013] According to some embodiments of the present invention, a plurality of spiral grooves are provided on the surfaces of the second cylindrical section and the third cylindrical section, and the plurality of spiral grooves are centrosymmetric about the axis center of the driving shaft.

[0014] According to some embodiments of the present invention, a first guiding and adjusting assembly and a second guiding and adjusting assembly are provided. The workpiece shaft is in driving connection with the first guiding and adjusting assembly, the driving shaft is in driving connection with the second guiding and adjusting assembly, and the guiding and adjusting directions of the first guiding and adjusting assembly and the second guiding and adjusting assembly are both parallel to the Y-axis.

[0015] According to some embodiments of the present invention, the multi-axis moving platform further has a driving stroke of the C-axis, and the C-axis is the direction of rotation around the Z-axis.

[0016] According to the control method of the continuously ultrasonic composite rolling gear according to the second aspect embodiment of the present invention, the above-mentioned numerical control equipment for the continuously ultrasonic composite rolling gear is used, and the gear is subjected to ultrasonic composite rolling through the following steps; Step S1, the gear to be processed is fixed on the workpiece shaft, a rolling gear with the same module and pressure angle as the gear to be processed is selected, and the rolling gear is arranged on the driving shaft; Step S2, move the workpiece shaft and the driving shaft along the Y-axis direction, adjust the meshing clearance between the gear to be processed and the rolling gear, and adjust the meshing clearance within the set threshold; Step S3, the ultrasonic vibration assembly drives the rolling gear to perform ultrasonic vibration, the multi-axis moving platform drives the rolling gear to move forward, and at the same time the driving shaft drives the rolling gear to rotate, so that the rolling gear and the gear to be processed generate meshing transmission. The rolling gear moves and rolls along the X-axis direction. After feeding from one end of the gear to be processed to the other end, the gear to be processed rotates synchronously for one week, the rolling gear moves in the reverse direction to reset, the gear to be processed rotates by one pitch, and the rolling gear moves along the X-axis direction for the next rolling. Repeat until all tooth surfaces of the gear to be processed are completed with rolling.

[0017] The control method of the continuously ultrasonic composite rolling gear according to the embodiment of the present invention has at least the following beneficial effects: controlling the multi-axis moving platform can drive the rolling gear to move in space, so that the processing curve of the rolling gear can follow the tooth surface contour of the gear to be processed in real time; the driving shaft rotates around its own axis, and the rolling gear and the gear to be processed maintain meshing transmission, which can continuously roll the gear to be processed, improving the ultrasonic rolling performance and efficiency.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Brief Description of the Drawings

[0019] The present invention will be further described below in conjunction with the drawings and embodiments, where: Figure 1 is a top view schematic diagram of the numerical control device for the first type of continuously ultrasonic composite rolling gear in the embodiment of the present invention; Figure 2 is a top view schematic diagram of the numerical control device for the second type of continuously ultrasonic composite rolling gear in the embodiment of the present invention.

[0020] Reference Numerals in the Drawings: Multi-axis moving platform 100, workpiece shaft 200, driving shaft 300, first cylindrical section 310, first curve transition section 320, second cylindrical section 330, third cylindrical section 340, second curve transition section 350, rolling gear 400, ultrasonic vibration assembly 500, transducer 510, amplitude transformer 520, first guiding and adjusting assembly 600, second guiding and adjusting assembly 700, flange 800, gear to be machined 900. Detailed Embodiments

[0021] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as up and down, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0023] In the description of the present invention, "a plurality of" means more than two. If there is a description of first and second, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0024] In the description of the present invention, unless otherwise clearly defined, terms such as "arrangement", "installation", and "connection" should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0025] Refer to Figure 1As shown, a numerical control device capable of continuous ultrasonic composite rolling of gears according to an embodiment of the present invention comprises a multi-axis moving platform 100 , a workpiece axis 200 , a driving axis 300 , a rolling gear 400 and an ultrasonic vibration component 500 .

[0026] The multi-axis mobile platform 100 has driving strokes of the X-axis, Y-axis, Z-axis and B-axis, wherein the X-axis, Y-axis and Z-axis are perpendicular to each other, and the B-axis is the direction of rotation around the Y-axis. In some embodiments, the plane formed by the X-axis and the Y-axis is a horizontal plane, and the Z-axis is perpendicular to the horizontal plane, and the Z-axis is in the vertical direction. In order to realize the driving strokes in the directions of the X-axis, Y-axis and Z-axis, the multi-axis mobile platform 100 can use high-precision roller linear guides, which can realize three-axis linkage adjustment and feeding, and has high rigidity and high damping characteristics.

[0027] The workpiece axis 200 is parallel to the X axis, and the end of the workpiece axis 200 is used to clamp the gear 900 to be processed. An adjustable self-centering three-jaw chuck or a special gear fixture can be set at the end of the workpiece axis 200 to clamp the gear to be processed. It should be understood that the three-jaw chuck and other fixtures are mature technologies, and their structure will not be described in detail here.

[0028] The driving shaft 300 is parallel to the workpiece axis 200, and the driving shaft 300 can be driven to rotate around the axis of the driving shaft 300, and the driving shaft 300 is connected to the multi-axis mobile platform 100. The multi-axis mobile platform 100 can drive the driving shaft 300 to move along the X-axis, Y-axis, Z-axis and B-axis in space. In addition, the driving shaft 300 can also be driven to rotate around its own axis. For example, a servo spindle motor is provided to be connected to the driving shaft 300 for transmission, which belongs to conventional technology and can realize the continuous rotation of the driving shaft 300 and the precise division according to different module gears. Furthermore, a rotary encoder can be installed to perform closed-loop control of the rotation angle. Preferably, the division progress of the rotation of the driving shaft 300 can reach 0.001° to ensure the progress of ultrasonic-assisted rolling. The driving shaft 300 can also support constant speed and variable speed control to match the rhythm of ultrasonic-assisted rolling.

[0029] The multi-axis mobile platform 100 drives the driving shaft 300, so that the rolling gear 400 on the driving shaft 300 can move along the Z axis for vertical adjustment to ensure that the rolling gear 400 is at the same height as the gear to be processed. The rolling gear 400 can move along the X axis for axial feeding, that is, move along the axial direction of the gear to be processed to achieve full tooth width coverage. The rolling gear 400 can move along the Y axis to control the rolling gear 400 to feed the tooth surface of the gear to be processed, adjust or apply rolling force. The rolling gear 400 can rotate on the B axis to adapt to the helical tooth contact angle, for example, the gear to be processed is a helical gear. The multi-axis mobile platform 100 can drive the rolling gear 400 to move in space, so that the processing curve of the rolling gear 400 follows the tooth surface contour of the gear to be processed in real time.

[0030] The rolling gear 400 is arranged at the end of the driving shaft 300 and is used to mesh with the gear to be processed; the ultrasonic vibration assembly 500 is connected to the rolling gear 400 and applies ultrasonic vibration to the rolling gear 400.

[0031] When performing ultrasonic-assisted rolling machining on the gear to be processed, the ultrasonic vibration assembly 500 applies ultrasonic vibration to the rolling gear 400. At the same time, the driving shaft 300 rotates around its own axis, and the rolling gear 400 remains in meshing transmission with the gear to be processed. When the rolling gear 400 and the gear to be processed are in meshing transmission, ultrasonic-assisted rolling can be carried out, enabling continuous rolling of the gear to be processed and improving the ultrasonic rolling performance and efficiency. During the meshing process of the rolling gear 400 and the gear to be processed, it is necessary to ensure that the meshing line of the gears is continuous and has sufficient contact ratio. Generally, it is ensured that the contact ratio ε > 1.

[0032] It can be understood that the ultrasonic vibration assembly 500 includes a transducer 510 and a horn 520. The horn 520 is arranged at the end of the driving shaft 300 and is coaxially arranged with the driving shaft 300. The transducer 510 is connected to the horn 520.

[0033] The transducer 510 is a device that converts electromagnetic energy into mechanical energy and is used to connect an ultrasonic signal generator (high-frequency electrical signal). In some embodiments, the transducer 510 can adopt piezoelectric ceramics and can stack multiple piezoelectric ceramics. For example, the power of a single piezoelectric ceramic is 1 kW. After stacking four piezoelectric ceramics, the total power can reach 4 kW. Further, a cooling jacket can be arranged at the piezoelectric ceramics to cool the piezoelectric ceramics and reduce the risk of overheating of the piezoelectric ceramics, enabling them to operate for a long time. The horn 520 is connected to the transducer 510 and is used to amplify the mechanical vibration amplitude and concentrate the ultrasonic energy. The horn 520 focuses the ultrasonic energy on a smaller area by changing the vibration displacement or speed, thereby increasing the power density of the ultrasonic wave. The rolling gear 400 is used to be connected to the output end of the horn 520.

[0034] Refer to Figure 2 As shown, it can be understood that the horn 520 and the driving shaft 300 are of an integral structure. The driving shaft 300 is provided with a variable-amplitude section, and the variable-amplitude section includes a first cylindrical section 310, a first curve transition section 320, and a second cylindrical section 330. The diameter of the first cylindrical section 310 is larger than that of the second cylindrical section 330. The first curve transition section 320 smoothly connects the first cylindrical section 310 and the second cylindrical section 330. The second cylindrical section 330 extends along the axial direction of the driving shaft 300 to the end of the driving shaft 300. The first cylindrical section 310, the first curve transition section 320, and the second cylindrical section 330 together constitute the horn 520, and the rolling gear 400 is connected to the second cylindrical section 330.

[0035] Further, both ends of the workpiece shaft 200 are used to clamp the gear to be processed. The driving shaft 300 is further provided with a third cylindrical section 340. The third cylindrical section 340 is located on the opposite side of the second cylindrical section 330. The diameter of the third cylindrical section 340 is smaller than that of the first cylindrical section 310. A second curve transition section 350 is provided between the third cylindrical section 340 and the first cylindrical section 310. A rolling gear 400 is also connected to the third cylindrical section 340.

[0036] Both the workpiece shaft 200 and the driving shaft 300 are of symmetric structures, which can ensure the uniform stress of the entire numerical control equipment and can also realize the simultaneous ultrasonic-assisted rolling of two gears to be processed, further improving the efficiency.

[0037] Further, the generatrices of the first curve transition section 320 and the second curve transition section 350 are both Gaussian curves.

[0038] Designing the generatrices of the first curve transition section 320 and the second curve transition section 350 as Gaussian curves can reduce the stress concentration value, solve the problem of easy fatigue fracture at the vicinity of the sudden change in the details, and at the same time make the actual resonance frequency of the horn 520 close to the theoretical value.

[0039] It can be understood that the length of the driving shaft 300 is L, the lengths of the second cylindrical section 330 and the third cylindrical section 340 are both 0.1L, the diameters are both 0.35R, the length of the first cylindrical section 310 is 0.2L, the diameter is R, the axial lengths of the first curve transition section 320 and the second curve transition section 350 are both 0.3L, and the Gaussian curve function satisfies the following formula: , (1); , (2); Among them, K is the attenuation ratio coefficient, and X is the distance in the X-axis direction.

[0040] Considering that the driving shaft 300 has the effect of a horn, it is necessary to meet the strength and stiffness requirements of the horn. The driving shaft 300 is preferably made of titanium alloy material.

[0041] In some embodiments, the driving shaft 300 is made of titanium alloy, and the attenuation ratio coefficient K is set to 0.35. Then the coefficient β of the Gaussian curve satisfies: , Substituting β into formula (1), the Gaussian curve function can be determined.

[0042] Furthermore, modal analysis is carried out to ensure no high-order modal interference, and parameters can be adjusted to avoid resonance. First, the first-order longitudinal vibration mode, i.e., the working mode, is obtained; as well as the second to fourth-order transverse / bending modes, high-frequency interference modes greater than or equal to the fifth order and their corresponding modal participation factors. The propagation speed of sound in the drive shaft 300 is 5090 m / s, and then frequency offset correction is performed. When the frequency exceeds 21000 Hz, the total length L of the drive shaft 300 is increased to reduce the frequency; if the frequency is lower than 19000 Hz, the total length L of the drive shaft 300 is decreased. When significant stress concentration appears in the horn section of the drive shaft 300, exceeding the tensile strength of its material (titanium alloy), the attenuation factor is decreased in proportion by 0.95 until the stress is not higher than the tensile strength of the titanium alloy. Through the above adjustments, it is ensured that there is no high-order modal interference in the horn section of the drive shaft 300 within the working frequency range (20 kHz ± 5%). Further, a laser Doppler vibrometer can be used to measure the vibration mode to determine whether the ultrasonic rolling amplitude conforms to the actual working conditions. If the measured vibration mode differs from the theoretical value by more than 10%, the amplitude can be changed by increasing or decreasing the power of the ultrasonic power supply until the requirements are met.

[0043] It can be understood that a plurality of flanges 800 are also provided on the drive shaft 300. The flanges 800 are coaxial with the drive shaft 300 and sleeved on the drive shaft 300, and are located at the vibration mode nodes of the horn section of the drive shaft 300. Therefore, the flanges 800 do not consume ultrasonic vibration energy. By adjusting the flanges 800, the transverse mode and its participation factor can be optimized.

[0044] It can be understood that a plurality of spiral grooves are provided on the surfaces of the second cylindrical section 330 and the third cylindrical section 340, and the plurality of spiral grooves are centrosymmetric about the axis center of the drive shaft 300.

[0045] The rolling gear 400 is arranged on the second cylindrical section 330 and the third cylindrical section 340. Taking the arrangement of the rolling gear 400 on the second cylindrical section 330 as an example, the spiral groove is located at the contact surface between the rolling gear 400 and the second cylindrical section 330. When the driving shaft 300 drives the rolling gear 400 to rotate, it needs to be opposite to the spiral direction of the spiral groove. During the ultrasonic-assisted rolling process, the force borne by the rolling gear 400 is decomposed into a radial force and an axial force towards the first cylindrical section 310 on the spiral groove. As the ultrasonic-assisted rolling progresses, the connection between the rolling gear 400 and the second cylindrical section 330 becomes tighter. This is because a first curve transition section 320 is arranged between the second cylindrical section 330 and the first cylindrical section 310. In the direction from the second cylindrical section 330 towards the first cylindrical section 310, the diameter of the first curve transition section 320 gradually increases. Therefore, the first curve transition section 320 can limit the axial movement of the rolling gear 400 and make the connection between the rolling gear 400 and the second cylindrical section 330 tighter. At the same time, when the driving shaft 300 is a symmetric structure, that is, a rolling gear 400 is arranged on both the second cylindrical section 330 and the third cylindrical section 340, the axial component forces of the forces borne by the rolling gear 400 on the spiral groove reach balance. Specifically, the axial component force on the second cylindrical section 330 is in the direction from the second cylindrical section 330 towards the first cylindrical section 310, and the axial component force on the third cylindrical section 340 is in the direction from the third cylindrical section 340 towards the first cylindrical section 310, and the two are opposite to each other. Further, protrusions are arranged on the rolling gear 400 to cooperate with the spiral groove, so that the driving shaft 300 can drive the rolling gear 400 to rotate. At the same time, the cooperation between the protrusions and the spiral groove can reduce the transmission of sound waves from the amplitude transformer section of the driving shaft 300 to the rolling gear 400, reduce the influence on the vibration mode of the rolling gear 400, and at the same time ensure the contact strength between the rolling gear 400 and the driving shaft 300, ensuring the effectiveness of vibration transmission.

[0046] It can be understood that a first guiding and adjusting assembly 600 and a second guiding and adjusting assembly 700 are provided. The workpiece shaft 200 is in transmission connection with the first guiding and adjusting assembly 600, and the driving shaft 300 is in transmission connection with the second guiding and adjusting assembly 700. The guiding and adjusting directions of the first guiding and adjusting assembly 600 and the second guiding and adjusting assembly 700 are both parallel to the Y-axis.

[0047] The first guiding and adjusting assembly 600 and the second guiding and adjusting assembly 700 can respectively adjust the positions of the workpiece shaft 200 and the driving shaft 300 in the Y-axis direction, so as to adjust the gap between the rolling gear 400 and the gear to be machined.

[0048] It should be understood that the clearance between the rolling gear 400 and the gear to be processed can be measured by the feeler gauge method. In one embodiment, the clearance between the rolling gear 400 and the gear to be processed is approximately 6 μm. The workpiece shaft 200 can be moved by the first guiding and adjusting assembly 600 to adjust the gear to be processed, reduce the center distance between the gear to be processed and the rolling gear 400, and ensure that the clearance does not exceed 1 μm.

[0049] In a specific adjustment process, the gear to be processed is used as the driven gear, and the rolling gear 400 is used as the driving gear. The driven gear is fixed, and a dial indicator is installed at the end of the driving gear shaft. The driving gear is gently rotated in two directions to measure the angle or displacement within the free rotation range. The formula for converting the side clearance is: , where ΔD is the total radial runout of the gear and b is the side clearance.

[0050] It can be understood that the multi-axis moving platform 100 also has a driving stroke for the C-axis, and the C-axis is the direction of rotation around the Z-axis.

[0051] When the rolling gear 400 performs ultrasonic-assisted rolling, it can also be adjusted by rotating around the Z-axis in real time to adapt to the contact angle of special-shaped teeth, such as drum-shaped gears.

[0052] A control method for continuously ultrasonic composite rolling gears according to an embodiment of the present invention uses the above-mentioned numerical control equipment for continuously ultrasonic composite rolling gears, and performs ultrasonic composite rolling on the gears through the following steps; Step S1, the gear to be processed is fixed on the workpiece shaft, and a rolling gear with the same module and pressure angle as the gear to be processed is selected and set on the driving shaft; Step S2, move the workpiece shaft and the driving shaft along the Y-axis direction to adjust the meshing clearance between the gear to be processed and the rolling gear, and adjust the meshing clearance within the set threshold; Step S3, the ultrasonic vibration assembly drives the rolling gear to perform ultrasonic vibration, the multi-axis moving platform drives the rolling gear to move forward, and at the same time the driving shaft drives the rolling gear to rotate, so that the rolling gear and the gear to be processed generate meshing transmission. The rolling gear moves and rolls along the X-axis direction. After feeding from one end of the gear to be processed to the other end, the gear to be processed rotates synchronously for one week, the rolling gear moves in the reverse direction to reset, the gear to be processed rotates by one pitch, and the rolling gear moves along the X-axis direction for the next rolling. Repeat until all tooth surfaces of the gear to be processed are rolled.

[0053] In addition, preferably, the number of teeth of the rolling gear and the gear to be machined should not be too close. If the number of teeth of both is the same, resonance will occur, causing modal interference to the ultrasonic rolling device. Further preferably, the difference in the number of teeth between the rolling gear and the gear to be machined is not less than 2. At the same time, preferably, the tooth ratio is not an integer, which can avoid resonance and local wear of the gear.

[0054] Through the above control, while the rolling gear and the gear to be machined are engaged in transmission, the rolling gear can also follow the tooth surface contour of the gear to be machined in real time, apply a stable rolling force, and complete ultrasonic rolling strengthening at the same time. The tooth surfaces of the rolling gear and the gear to be machined are in continuous contact, maintaining a constant pressing force and position following to prevent impact and interrupted pressing. Under the control of the multi-axis moving platform, the rolling gear can perform linkage on the X-axis, Y-axis, and B-axis, and can calculate the rolling trajectory in real time through the interpolation algorithm, so that the rolling gear can follow the tooth surface contour of the gear to be machined in real time. Interpolation, that is, the process by which the machine tool numerical control system determines the tool movement trajectory according to a certain method, is a prior art. Preferably, the interpolation frequency is greater than or equal to 500 Hz. Further, tooth surface envelope following compensation can also be performed to ensure that the contact area of the rolling gear is always located at the center of the tooth surface of the gear to be machined. For the gear to be machined with helical teeth or drum-shaped teeth, a spatial surface fitting algorithm needs to be used to generate a three-dimensional trajectory. When the rolling gear performs ultrasonic-assisted rolling on the gear to be machined, the ultrasonic vibration mode includes longitudinal vibration and transverse vibration. Longitudinal vibration means that the ultrasonic wave direction is the same as the rolling contact force direction, which is suitable for directly applying a micro-hammering force to the tooth surface of the gear to be machined to improve the effect of gear plastic deformation; transverse vibration means that during the rolling process, there is a micro-slip along the contact surface direction between the rolling gear and the gear to be machined, which helps to improve the surface finish and hardening layer uniformity of the tooth surface of the gear to be machined.

[0055] In some embodiments, the gear to be machined is a helical gear, and the swing angle range of the rolling gear on the B-axis can be ±20°. By adjusting the swing angle of the B-axis, the rolling line can be kept consistent with the tooth line along the tooth width direction. In some embodiments, the gear to be machined is a drum-shaped gear, and the rolling gear performs linkage adjustment on the B-axis and C-axis, and the swing angle range can be ±15°, and it is variable-angle rolling. The middle of the tooth width of the drum-shaped gear protrudes, and variable-angle following of the curvature change is required. In some embodiments, the gear to be machined is an arc tooth or a special-shaped tooth, and the swing angle of the rolling gear needs to be adjusted in real time depending on the digital model trajectory to accurately fit the non-standard tooth surface curvature.

[0056] The above has described the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A numerical control device capable of continuous ultrasonic composite rolling of gears, characterized in that: include: A multi-axis mobile platform (100), the multi-axis mobile platform (100) having driving strokes of an X-axis, a Y-axis, a Z-axis and a B-axis, wherein the X-axis, the Y-axis and the Z-axis are mutually perpendicular in pairs, and the B-axis is a direction of rotation about the Y-axis; A workpiece shaft (200), the workpiece shaft (200) being parallel to the X-axis, and the end of the workpiece shaft (200) being used to clamp the gear to be processed; A driving shaft (300), the driving shaft (300) being parallel to the workpiece shaft (200), the driving shaft (300) being capable of being driven to rotate around the axis of the driving shaft (300), and the driving shaft (300) being connected to the multi-axis mobile platform (100); A rolling gear (400), the rolling gear (400) being arranged at the end of the driving shaft (300), the rolling gear (400) being used to mesh with the gear to be processed; An ultrasonic vibration component (500), the ultrasonic vibration component (500) is connected to the rolling gear (400) and applies ultrasonic vibration to the rolling gear (400).

2. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 1, characterized in that: The ultrasonic vibration component (500) comprises a transducer (510) and an horn (520), wherein the horn (520) is arranged at the end of the driving shaft (300), the horn (520) is coaxially arranged with the driving shaft (300), and the transducer (510) is connected to the horn (520).

3. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 2, characterized in that: The amplitude changing rod (520) and the driving shaft (300) are of an integrated structure; the driving shaft (300) is provided with an amplitude changing section, the amplitude changing section comprising a first cylindrical section (310), a first curved transition section (320) and a second cylindrical section (330); the diameter of the first cylindrical section (310) is greater than the diameter of the second cylindrical section (330); the first curved transition section (320) smoothly connects the first cylindrical section (310) and the second cylindrical section (330); the second cylindrical section (330) extends along the axial direction of the driving shaft (300) to the end of the driving shaft (300); the first cylindrical section (310), the first curved transition section (320) and the second cylindrical section (330) together constitute the amplitude changing rod (520); and the rolling gear (400) is connected to the second cylindrical section (330).

4. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 3, characterized in that: Both ends of the workpiece shaft (200) are used to clamp the gear to be processed. The driving shaft (300) is also provided with a third cylindrical section (340). The third cylindrical section (340) is located on the opposite side of the second cylindrical section (330). The diameter of the third cylindrical section (340) is smaller than the diameter of the first cylindrical section (310). A second curved transition section (350) is provided between the third cylindrical section (340) and the first cylindrical section (310). The third cylindrical section (340) is also connected to one of the rolling gears (400).

5. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 4, characterized in that: The generatrix of the first curve transition section (320) and the generatrix of the second curve transition section (350) are both Gaussian curves.

6. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 5, characterized in that: The length of the driving shaft (300) is L, the length of the second cylindrical section (330) and the third cylindrical section (340) are both 0.1L and 0.35R in diameter, the length of the first cylindrical section (310) is 0.2L and 0.35R in diameter, the axial length of the first curved transition section (320) and the second curved transition section (350) are both 0.3L, and the Gaussian curve function satisfies the following formula: ； ； Wherein, K is the attenuation proportional coefficient, and X is the distance in the X-axis direction.

7. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 6, characterized in that: The surfaces of the second cylindrical section (330) and the third cylindrical section (340) are both provided with a plurality of spiral grooves, and the plurality of spiral grooves are symmetrical around the axis of the driving shaft (300).

8. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 1, characterized in that: A first guide adjustment component (600) and a second guide adjustment component (700) are provided, the workpiece shaft (200) is transmission-connected to the first guide adjustment component (600), the driving shaft (300) is transmission-connected to the second guide adjustment component (700), and the guide adjustment direction of the first guide adjustment component (600) and the guide adjustment direction of the second guide adjustment component (700) are both parallel to the Y-axis.

9. The numerical control equipment capable of continuous ultrasonic composite rolling of gears according to claim 1, characterized in that: The multi-axis mobile platform (100) also has a C-axis driving stroke, and the C-axis is a direction of rotation around the Z-axis.

10. A control method for continuous ultrasonic composite rolling of gears, characterized in that: Using the numerical control equipment capable of continuous ultrasonic composite rolling of gears as claimed in any one of claims 1 to 9, and performing ultrasonic composite rolling of gears through the following steps; Step S1, the gear to be processed is fixed on the workpiece shaft, a rolling gear having the same module and pressure angle as the gear to be processed is selected, and the rolling gear is set on the driving shaft; Step S2, moving the workpiece axis and the driving axis along the Y-axis direction, adjusting the meshing clearance between the gear to be processed and the rolling gear, and adjusting the meshing clearance to within a set threshold; Step S3, the ultrasonic vibration component drives the rolling gear to ultrasonically vibrate, the multi-axis mobile platform drives the rolling gear to move and feed, and the active shaft drives the rolling gear to rotate, so that the rolling gear and the gear to be processed produce meshing transmission, and the rolling gear moves along the X-axis direction for rolling. After feeding from one end of the gear to be processed to the other end, the gear to be processed rotates synchronously for one circle, the rolling gear moves in the opposite direction to reset, the gear to be processed rotates one tooth pitch, and the rolling gear moves along the X-axis direction for the next rolling, and repeats until all tooth surfaces of the gear to be processed are rolled.

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