An ultrasonic-assisted broaching machine tool based on resonant broach and design method

Abstract

This application discloses an ultrasonic-assisted broaching machine tool and its design method based on a resonant broach. The machine tool includes: a broaching structure; an ultrasonic broach with its groove located at the position corresponding to the peak of the broach's vibration mode; a main piezoelectric actuator device disposed in the groove; a compensating piezoelectric actuator device disposed at the position corresponding to the radial vibration mode on the ultrasonic broach; and an ultrasonic power supply. The main power supply frequency is the frequency corresponding to the maximum axial ultrasonic vibration amplitude and the minimum radial ultrasonic vibration amplitude under different power supply frequencies. The main driving voltage is determined based on the main power supply frequency, the preset maximum broaching speed of the broach, and the ultrasonic-assisted broaching effectiveness coefficient. The compensating power supply frequency is the same as the main power supply frequency but with a phase difference of 180°. The compensating driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold among different driving voltages. This application enables ultrasonic assistance for broaches that require frequent clamping.

Description

Technical Field

[0001] This application relates to the technical field of broaching, and in particular to an ultrasonic-assisted broaching machine tool based on a resonant broach and its design method. Background Technology

[0002] Ultrasonic assistance can significantly improve the machining performance of materials with high hardness and high strength. Adding ultrasonic assistance to broaching can significantly improve the machining capabilities of existing broaching machines, reduce machine tool manufacturing costs, reduce cutting deformation and tool wear, and improve machining accuracy. However, because the workpiece is self-positioned in broaching (positioned by the broaching motion of the broach), it is difficult to fix the workpiece and excite ultrasonic vibration by adding an ultrasonic device to the worktable. Existing ultrasonic broaches are only used for side broaching and are not frequently clamped. By connecting the broach to an ultrasonic amplitude transformer, the amplitude transformer drives the broach movement, eliminating the need for frequent tool changes. However, machine tool broaching tools require frequent clamping, making it difficult to add an ultrasonic device to the clamping end of the broaching machine. Existing technologies also involve connecting the clamping body to the broach and the ultrasonic amplitude transformer to the clamping body, with the clamping body holding the broach. However, this method has difficulty transmitting ultrasonic vibration to the broach, resulting in low energy transmission efficiency, and the clamping body has a large mass, which makes it difficult for the ultrasonic device to excite ultrasonic vibration between the clamping body and the broach, significantly increasing the weight. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an ultrasonic-assisted broaching machine tool based on a resonant broach, which can realize ultrasonic assistance for broaches that require frequent clamping, thereby improving machining accuracy and efficiency.

[0004] This application also provides a design method for an ultrasonic-assisted broaching machine tool based on a resonant broach, a control device for obtaining the target broach vibration mode and the compensated broach vibration mode, and a computer-readable storage medium.

[0005] An ultrasonic-assisted broaching machine tool according to a first aspect embodiment of this application includes:

[0006] The broaching machine structure has a tool clamping body and a tool feeding device;

[0007] An ultrasonic baffle has one end engaged with the baffle body and the other end connected to the baffle delivery device. The ultrasonic baffle has a groove located at the position corresponding to the peak of the baffle's vibration mode.

[0008] The main piezoelectric actuator device is disposed in the groove;

[0009] A compensating piezoelectric actuator device is disposed at the position corresponding to the radial vibration mode on the ultrasonic broach, and the polarization direction of the compensating piezoelectric actuator device is orthogonal to the polarization direction of the main piezoelectric actuator device.

[0010] An ultrasonic power supply is electrically connected to both the main piezoelectric actuator device and the compensating piezoelectric actuator device. The ultrasonic power supply is used to generate the target broach vibration mode to excite the ultrasonic broach to produce high-frequency ultrasonic vibration, and to generate a compensating broach vibration mode to symmetrically compensate for the radial vibration generated by the ultrasonic broach. The target broach vibration mode is generated at the main power supply frequency and the main driving voltage, and the compensating broach vibration mode is generated at the compensating power supply frequency and the compensating driving voltage. The main power supply frequency is such that the axial ultrasonic vibration amplitude is the upper limit boundary value at different power supply frequencies. The radial ultrasonic vibration amplitude is the frequency corresponding to the radial lower limit boundary value. The main driving voltage is determined based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. The compensation power supply frequency is the same as the main power supply frequency, with a phase difference of 180°. The compensation driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage.

[0011] The ultrasonic-assisted broaching machine tool based on a resonance broach according to the embodiments of this application has at least the following beneficial effects:

[0012] This application significantly reduces the structure and number of parts of the ultrasonic device by setting a main piezoelectric actuator on the ultrasonic broach and using the broach as the ultrasonic vibration amplitude transformer, thus meeting the requirements of frequent broach assembly. However, using the broach as the ultrasonic vibration amplitude transformer will generate ultrasonic axial and radial vibrations. The radial ultrasonic vibration amplitude will significantly reduce the dimensional accuracy of broaching. It is necessary to maximize the axial ultrasonic vibration amplitude and minimize the radial ultrasonic vibration amplitude. This application improves machining accuracy and efficiency by setting the main power supply frequency of the main piezoelectric actuator to the frequency corresponding to the upper limit of the axial ultrasonic vibration amplitude and the lower limit of the radial ultrasonic vibration amplitude under different power supply frequencies. It determines the main driving voltage of the main piezoelectric actuator based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. Furthermore, it sets a compensating piezoelectric actuator at the position corresponding to the radial vibration mode of the ultrasonic broach, and controls the polarization direction of the compensating piezoelectric actuator to be orthogonal to the polarization direction of the main piezoelectric actuator. The compensating driving voltage is set to the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator generates high-frequency ultrasonic vibration under the main driving voltage.

[0013] According to some embodiments of this application, the target preload between the main piezoelectric actuator device and the ultrasonic broach is the preload corresponding to the difference between the axial ultrasonic vibration amplitude and the radial ultrasonic vibration amplitude of the ultrasonic broach under the target broach vibration mode, which is the upper limit boundary value of the difference.

[0014] According to some embodiments of this application, the ultrasonic broach is further provided with a counterweight structure, which is located at an overall symmetrical position between the main piezoelectric actuator device and the compensating piezoelectric actuator device.

[0015] According to some embodiments of this application, the main piezoelectric actuator device includes four main piezoelectric ceramics, which are stacked symmetrically in a ring, with adjacent main piezoelectric ceramics having opposite polarization directions.

[0016] The design method of the ultrasonic-assisted broaching machine tool based on a resonant broach according to the second aspect of this application, applied to the ultrasonic-assisted broaching machine tool based on a resonant broach described in the first aspect of the present application, includes:

[0017] Obtain the positions corresponding to the baffle mode peaks and the radial vibration modes on the ultrasonic baffle.

[0018] The main piezoelectric actuator is positioned at the position corresponding to the peak of the ultrasonic broach vibration mode, and the compensating piezoelectric actuator is positioned at the position corresponding to the radial vibration mode on the ultrasonic broach.

[0019] The ultrasonic power supply is controlled to generate the target broach vibration mode on the main piezoelectric actuator device to excite the ultrasonic broach to generate ultrasonic high-frequency vibration. The target broach vibration mode is generated under the main power supply frequency and the main driving voltage. The main power supply frequency is the frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value of the axial direction and the radial ultrasonic vibration amplitude being the lower limit boundary value of the radial direction at different power supply frequencies. The main driving voltage is determined according to the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient.

[0020] The ultrasonic power supply is controlled to generate the compensated broach vibration mode of the compensated piezoelectric actuator device to symmetrically compensate for the radial vibration generated by the ultrasonic broach. The compensated broach vibration mode is generated under the compensated power supply frequency and the compensated driving voltage. The compensated power supply frequency is the same as the main power supply frequency but has a phase difference of 180°. The compensated driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude of the compensated piezoelectric actuator device being less than or equal to a preset threshold when the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage.

[0021] The design method of the ultrasonic-assisted broaching machine tool based on resonance broach according to the embodiments of this application has at least the following beneficial effects:

[0022] This application significantly reduces the structure and number of parts of the ultrasonic device by setting a main piezoelectric actuator on the ultrasonic broach and using the broach as the ultrasonic vibration amplitude transformer, thus meeting the requirements of frequent broach assembly. However, using the broach as the ultrasonic vibration amplitude transformer will generate ultrasonic axial and radial vibrations. The radial ultrasonic vibration amplitude will significantly reduce the dimensional accuracy of broaching. It is necessary to maximize the axial ultrasonic vibration amplitude and minimize the radial ultrasonic vibration amplitude. This application improves machining accuracy and efficiency by setting the main power supply frequency of the main piezoelectric actuator to the frequency corresponding to the upper limit of the axial ultrasonic vibration amplitude and the lower limit of the radial ultrasonic vibration amplitude under different power supply frequencies. It determines the main driving voltage of the main piezoelectric actuator based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. Furthermore, it sets a compensating piezoelectric actuator at the position corresponding to the radial vibration mode of the ultrasonic broach, and controls the polarization direction of the compensating piezoelectric actuator to be orthogonal to the polarization direction of the main piezoelectric actuator. The compensating driving voltage is set to the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator generates high-frequency ultrasonic vibration under the main driving voltage.

[0023] According to some embodiments of this application, the target broach vibration mode and the compensated broach vibration mode are obtained through the following steps:

[0024] Obtain the position information of the main piezoelectric actuator device, the material parameters of the ultrasonic broach, and the preset initial preload;

[0025] A three-dimensional model of the broach is established based on the location information, the material parameters, and the preset initial preload.

[0026] Based on the three-dimensional model of the broach, modal simulations of different broach vibration modes under different power supply frequencies are performed. The frequencies corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value are extracted from all broach vibration modes and used as the main power supply frequency.

[0027] The main drive voltage is determined based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient.

[0028] The compensation power frequency is determined based on the main power frequency, and the compensation power frequency has the same magnitude as the main power frequency, with a phase difference of 180°.

[0029] When the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage, the radial ultrasonic vibration amplitude and axial ultrasonic vibration amplitude of the compensation piezoelectric actuator device under different driving voltages are measured. The driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold is selected as the compensation driving voltage.

[0030] The target broach vibration mode is generated based on the main power supply frequency and the main drive voltage, and the compensated broach vibration mode is generated based on the compensation power supply frequency and the compensation drive voltage.

[0031] According to some embodiments of this application, establishing a three-dimensional model of the broach based on the position information, the material parameters, and the preset initial preload includes:

[0032] The position information, material parameters, and preset initial preload are input into the finite element model, and boundary conditions are set to simulate the actual clamping state. The simulation is performed to obtain the three-dimensional model of the broach. The actual clamping state represents the clamping state of the ultrasonic broach and the clamping body. The clamping point between the ultrasonic broach and the clamping body is the broach vibration mode node.

[0033] According to some embodiments of this application, the method further includes:

[0034] Under the target broach vibration mode, the axial and radial ultrasonic vibration amplitudes of the ultrasonic broach are obtained corresponding to different preload forces between the main piezoelectric actuator device and the ultrasonic broach.

[0035] The difference between the axial and radial ultrasonic vibration amplitudes corresponding to each preload is determined, resulting in multiple differences;

[0036] The preload force corresponding to the upper limit boundary value of the multiple differences is determined as the target preload force between the main piezoelectric actuator device and the ultrasonic broach.

[0037] According to some embodiments of this application, when measuring the ultrasonic high-frequency vibration generated by the main piezoelectric actuator device under the main driving voltage, the compensation piezoelectric actuator device selects the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold as the compensation driving voltage, including:

[0038] When the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage, the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude is measured when the driving voltage of the compensated piezoelectric actuator device is successively 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times and 1 times the main driving voltage, and multiple ratios are obtained.

[0039] The driving voltage corresponding to a ratio less than or equal to a preset threshold is used as the compensation driving voltage.

[0040] According to some embodiments of this application, the constraint formula for the main drive voltage is:

[0041] ;

[0042] ;

[0043] in, The preset maximum broaching speed, The preset ultrasonic-assisted broaching effectiveness coefficient, The amplitude of ultrasonic vibration. The main power supply frequency, This refers to the main drive voltage.

[0044] The control device according to a third aspect embodiment of this application includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method for obtaining the target broach mode and the compensated broach mode in the design method of an ultrasonic-assisted broaching machine tool based on a resonant broach as described in the second aspect embodiment above. Since the control device employs all the technical solutions of the method for obtaining the target broach mode and the compensated broach mode in the design method of an ultrasonic-assisted broaching machine tool based on a resonant broach in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0045] According to a fourth aspect embodiment of this application, a computer-readable storage medium stores computer-executable instructions for performing the method for obtaining the target broach mode shape and the compensated broach mode shape in the design method of an ultrasonic-assisted broaching machine tool based on a resonant broach as described in the second aspect embodiment above. Since the computer-readable storage medium employs all the technical solutions of the method for obtaining the target broach mode shape and the compensated broach mode shape in the design method of an ultrasonic-assisted broaching machine tool based on a resonant broach in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0046] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing this application. Attached Figure Description

[0047] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0048] Figure 1 This is a schematic diagram of the structure of an ultrasonic-assisted broaching machine tool based on a resonance broach according to an embodiment of this application;

[0049] Figure 2 This is a schematic diagram of a mode node according to an embodiment of this application;

[0050] Figure 3 This is a flowchart illustrating the design method of an ultrasonic-assisted broaching machine tool based on a resonant broach, according to an embodiment of this application.

[0051] Figure label:

[0052] Tool body 100;

[0053] Ultrasonic baffle 200;

[0054] Main piezoelectric ceramic 300;

[0055] 400 ultrasonic vibration amplitude transformer. Detailed Implementation

[0056] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein 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 with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0057] In the description of this application, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0058] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0059] In the description of this application, it should be noted that, unless otherwise explicitly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0060] The following will combine Figures 1 to 3 The ultrasonic-assisted broaching machine tool based on resonance broaching tool of this application is clearly and completely described. Obviously, the embodiments described below are some embodiments of this application, not all embodiments.

[0061] refer to Figures 1 to 3 , Figure 1 This is a schematic diagram of the structure of an ultrasonic-assisted broaching machine tool based on a resonance broach according to an embodiment of this application; Figure 2 This is a schematic diagram of a mode node according to an embodiment of this application; Figure 3 This is a flowchart illustrating the design method of an ultrasonic-assisted broaching machine tool based on a resonant broach, according to an embodiment of this application.

[0062] An ultrasonic-assisted broaching machine tool based on a resonant broach according to a first aspect embodiment of this application includes a broaching structure, an ultrasonic broach 200, a main piezoelectric actuator device, a compensating piezoelectric actuator device, and an ultrasonic power supply.

[0063] The broaching machine structure includes a tool holder 100 and a tool feeding device.

[0064] The ultrasonic broach 200 has one end engaged with the broach body 100 and the other end connected to the broach feeding device. The ultrasonic broach 200 has a groove located at the position corresponding to the peak of the broach vibration mode.

[0065] The main piezoelectric actuator is located in the groove;

[0066] The compensating piezoelectric actuator device is located at the position corresponding to the radial vibration mode on the ultrasonic broach 200, and the polarization direction of the compensating piezoelectric actuator device is orthogonal to the polarization direction of the main piezoelectric actuator device.

[0067] An ultrasonic power supply is electrically connected to both the main piezoelectric actuator and the compensating piezoelectric actuator. The ultrasonic power supply generates a target broach vibration mode to excite the ultrasonic broach 200 to produce high-frequency ultrasonic vibration, and also generates a compensating broach vibration mode to symmetrically compensate for the radial vibration generated by the ultrasonic broach 200. The target broach vibration mode is generated at the main power supply frequency and the main driving voltage, while the compensating broach vibration mode is generated at the compensating power supply frequency and the compensating driving voltage. The main power supply frequency is the frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value at different power supply frequencies. The main driving voltage is determined based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. The compensating power supply frequency is the same as the main power supply frequency but has a 180° phase difference. The compensating driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator generates high-frequency ultrasonic vibration at the main driving voltage.

[0068] It is understood that the ultrasonic-assisted broaching machine tool of this application is based on the traditional broaching machine tool, except that the traditional broach is replaced with the ultrasonic broach 200 of this application. Except for the ultrasonic broach 200, the other structures are consistent with the structure of the traditional broaching machine tool. The basic working principle and working process of the broaching machine tool will not be described in detail here.

[0069] refer to Figure 1 This application significantly reduces the structure and number of parts of the ultrasonic device by setting a main piezoelectric actuator device on the ultrasonic broach 200 and using the broach as the ultrasonic vibration amplitude transformer 400, thus meeting the requirements of frequent broach assembly. However, using the broach as the ultrasonic vibration amplitude transformer 400 will generate ultrasonic axial and radial vibrations. The radial ultrasonic vibration amplitude will significantly reduce the dimensional accuracy of broaching. It is necessary to increase the axial ultrasonic vibration amplitude as much as possible and reduce the radial ultrasonic vibration amplitude.

[0070] It should be noted that, Figure 1 The ultrasonic vibration amplitude transformer 400 in this application is equivalent to the corresponding structure of the main piezoelectric actuator device and is part of the ultrasonic baffle 200. In other words, the ultrasonic vibration amplitude transformer 400 and the ultrasonic baffle 200 in this application are the same structure.

[0071] In some embodiments of this application, the main piezoelectric actuator device includes four main piezoelectric ceramics 300, corresponding to four grooves, which are embedded in the grooves of the ultrasonic baffle 200. The ultrasonic power supply converts conventional power into ultrasonic power, and the main piezoelectric ceramics 300, under the action of the ultrasonic power supply, become piezoelectric actuators, exciting the ultrasonic vibration amplitude transformer 400, i.e., the ultrasonic baffle 200, to generate high-frequency ultrasonic vibration. The main piezoelectric ceramics 300 are installed at positions corresponding to the peaks of the baffle's vibration mode, with the primary goal of exciting axial vibration.

[0072] In some embodiments of this application, the main piezoelectric actuator device includes four main piezoelectric ceramics 300, which are stacked symmetrically in a ring, with adjacent main piezoelectric ceramics 300 having opposite polarization directions. The four main piezoelectric ceramics 300 are symmetrically arranged along the axis of the ultrasonic broach 200, with their polarization directions aligned with the axial direction. This partitioning of the four main piezoelectric ceramics 300, with adjacent main piezoelectric ceramics 300 employing opposite polarization, enhances the uniformity of axial strain.

[0073] Polarization is the process by which piezoelectric ceramics align their domains in a directional manner under a high-voltage electric field, giving them the piezoelectric effect. Adjacent main piezoelectric ceramics 300 adopt reverse polarization (+ / - alternation) which means that the polarization directions of two adjacent main piezoelectric ceramics 300 are opposite (the polarization direction of one main piezoelectric ceramic 300 is +Z, and the polarization direction of the other main piezoelectric ceramic 300 is -Z).

[0074] The process of achieving reverse polarization is as follows: Four unpolarized main piezoelectric ceramics 300 of uniform size are selected. The main piezoelectric ceramics 300 are placed in a high-voltage electric field (usually 2kV / mm~4kV / mm), and the temperature is raised to slightly below the Curie point (e.g., 150℃). Forward polarization (+Z): the upper electrode is connected to a positive high voltage, and the lower electrode is grounded; reverse polarization (-Z): the upper electrode is grounded, and the lower electrode is connected to a positive high voltage; alternating arrangement: when stacked, the polarization directions of adjacent main piezoelectric ceramics 300 are opposite. The same-oriented electrodes of all main piezoelectric ceramics 300 (e.g., the +Z surface) are connected in parallel to the positive terminal of the ultrasonic power supply, and the -Z surface is connected in parallel to the negative terminal of the ultrasonic power supply. The actual electric field directions of adjacent main piezoelectric ceramics 300 are the same (both from top to bottom).

[0075] The principle behind reverse polarization enhancing axial strain uniformity is as follows: the axial strain of the main piezoelectric ceramic 300... Determined by the piezoelectric equation: ,in, It represents the longitudinal piezoelectric constant (with opposite signs for +Z and -Z polarization). Indicates the direction of the applied electric field (determined by the polarity of the driving voltage). If the polarization directions of adjacent main piezoelectric ceramics 300 are opposite ( The signs are opposite, but the electric field directions are also opposite (because the electrodes are reversed), so the strain directions are the same (negative times negative equals positive). For example, the first main piezoelectric ceramic 300 (+Z polarization): down (Elongation). Second main piezoelectric ceramic 300 (-Z polarization): up (Similar elongation). If all the main piezoelectric ceramics 300 have the same polarization direction, the electric field directions of adjacent main piezoelectric ceramics 300 will be opposite during series driving, causing one to elongate and the other to shorten, resulting in overall strain cancellation. Advantages of reverse polarization: By reversing the polarization direction and the electric field direction, the strain direction of all main piezoelectric ceramics 300 is ensured to be consistent, and the total displacement is greatly increased after superposition.

[0076] It should be noted that the number of main piezoelectric ceramics 300 can also be eight or other even numbers, and they are also stacked in a ring symmetrical manner. The polarization directions of two adjacent main piezoelectric ceramics 300 are opposite. The specific number of main piezoelectric ceramics 300 mentioned above should not be regarded as a limitation of this application.

[0077] In some embodiments of this application, the target broach mode of the main piezoelectric actuator device is obtained through the following steps:

[0078] Acquire the position information of the main piezoelectric actuator device, the material parameters of the ultrasonic broach 200, and the preset initial preload;

[0079] The position information, material parameters and preset initial preload are input into the finite element model, and boundary conditions are set to simulate the actual clamping state. The simulation is performed to obtain the three-dimensional model of the broach. The actual clamping state represents the clamping state of the ultrasonic broach 200 and the clamping body 100. The clamping point between the ultrasonic broach 200 and the clamping body 100 is the broach vibration mode node.

[0080] Based on the three-dimensional model of the broach, modal simulations of different broach vibration modes under different power supply frequencies were performed. The frequencies corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value were extracted from all broach vibration modes and used as the main power supply frequency.

[0081] The main drive voltage is determined based on the main power frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient.

[0082] The target broach vibration mode is generated based on the main power supply frequency and the main drive voltage.

[0083] The location information includes the quantity and position of the main piezoelectric ceramics 300. The material parameters of the ultrasonic broach 200 are high-speed steel or cemented carbide.

[0084] like Figure 2 As shown, the nodes of the broach vibration mode are the nodes where the vibration amplitude is 0 in the broach vibration mode, because the broach vibration mode is a sine wave or a cosine wave. Figure 2The position connecting the center and the Z-axis is the node of the broach vibration mode, with a vibration amplitude of 0. The broach vibration mode is obtained through modal analysis finite element calculation, thus yielding the node.

[0085] During modal simulation, the broach working condition is referenced, constraints are applied, and modal analysis is performed. The first 100 modes can be calculated. The axial resonant frequency (e.g., 20kHz) is selected as the interval, avoiding the mode shape of the adjacent radial mode. The axial (longitudinal) and radial (bending / torsion) natural frequencies and mode shapes of all broach vibration modes are extracted. The frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value of the axial mode and the radial ultrasonic vibration amplitude being the lower limit boundary value of the radial mode (i.e., the axial ultrasonic vibration amplitude is the largest and the radial ultrasonic vibration amplitude is the smallest) is selected as the main power supply frequency.

[0086] In some embodiments of this application, the constraint formula for the main drive voltage is:

[0087] ;Formula (1)

[0088] ;Formula (2)

[0089] in, The preset maximum broaching speed, The preset ultrasonic-assisted broaching effectiveness coefficient, The amplitude of ultrasonic vibration. Main power supply frequency, The main driving voltage.

[0090] The maximum broaching speed is generally related to the machine tool and is provided by the manufacturer, but there is a general range in the industry, which is usually 5m / min to 15m / min.

[0091] The effectiveness coefficient of ultrasonic-assisted broaching can be determined through orthogonal right-angle ultrasonic cutting experiments, by detecting changes in the cutting force during broaching. The value of is determined as follows:

[0092] (1) Turn on the ultrasonic power supply, assuming a rated power of 300W. Measure the ultrasonic vibration amplitude when the power is 50% using a Doppler laser vibrometer, and record it as follows: The main power supply frequency is By conducting orthogonal right-angle ultrasonic cutting experiments at different cutting speeds (e.g., with ultrasonic assistance) and comparing the cutting forces at different cutting speeds with and without ultrasonic assistance, it was determined that ultrasonic assistance failed when the ultrasonic-assisted cutting force exceeded 90% of the conventional cutting force (when the ultrasonic cutting force approached 80% of the conventional cutting force, ultrasonic assistance failed to reduce the cutting force and thus could not improve cutting performance; only when the cutting force was reduced could cutting performance be improved). The cutting speed under this ultrasonic-assisted cutting force was identified as the critical cutting speed. 1.

[0093] (2) Continue measuring the ultrasonic power supply at 40%, 30%, 20%, and 10% power as described above, and obtain the corresponding values. 2. 3. 4. 5. Considering the effectiveness of ultrasonic vibration at all power levels, 1. 2. 3. 4. The minimum value in 5 is determined as the final value. .

[0094] In some embodiments, under a cutting load of 10 tons, the maximum broaching speed is 15 m / min. It equals 0.377. The value of the main drive voltage can be calculated according to formula (1) and formula (2).

[0095] In some embodiments, the power of the ultrasonic power supply The following constraint formula is used for calculation:

[0096] ;Formula (3)

[0097] ;Formula (4)

[0098] in, The power of the ultrasonic power supply. The amplitude of ultrasonic vibration velocity. For system damping, The amplitude of ultrasonic vibration. Main power supply frequency, For a moment, This is the initial phase angle, which is typically 0.

[0099] In some embodiments of this application, when residual radial vibration still exists in the ultrasonic broach 200 with a symmetrical main piezoelectric ceramic 300 layout, it indicates that there is leakage of excitation energy in non-axial modes (such as bending or torsion). This application provides symmetrical compensation by setting a compensating piezoelectric actuator device at the position corresponding to the radial vibration mode of the ultrasonic broach 200, generating a counteracting torque or displacement, thereby neutralizing the radial vibration component. The radial vibration suppression condition must satisfy: the sum of the radial component generated by the main piezoelectric actuator device and the reverse radial component generated by the compensating piezoelectric actuator device is approximately equal to 0.

[0100] First, radial vibration measurement and modal identification experiments were conducted. An ultrasonic power supply generated the target broach vibration mode in the main piezoelectric actuator device to excite the ultrasonic broach 200 to produce high-frequency ultrasonic vibration. A laser Doppler vibrometer was used to scan the surface of the ultrasonic broach 200 to obtain the distribution of axial and radial ultrasonic vibration amplitudes. The vibration spectrum was analyzed using Fast Fourier Transform to identify the dominant frequency of radial vibration (e.g., bending mode frequency). Modal decomposition: If the radial vibration is a first-order bending mode, it manifests as the broach's ends oscillating in opposite directions; if it is a torsional mode, it manifests as the cross-section rotating around its axis.

[0101] The compensated piezoelectric actuator device is constructed in the form of a compensating piezoelectric ceramic. Based on the main piezoelectric ceramic 300 (symmetrically arranged), a compensating piezoelectric ceramic is added at the position corresponding to the radial vibration mode (e.g., at the antinode of the first-order bending mode). If the antinode of the first-order bending mode is located at 1 / 4 and 3 / 4 of the length of the ultrasonic broach 200, then the compensating piezoelectric ceramic is attached there. The polarization direction of the compensating piezoelectric ceramic is orthogonal to that of the main piezoelectric ceramic 300 (e.g., the main piezoelectric ceramic 300 is axially polarized, and the compensating piezoelectric ceramic is radially polarized).

[0102] By designing the polarization direction of the compensating piezoelectric ceramic to be orthogonal to the main piezoelectric ceramic 300 (e.g., the main piezoelectric ceramic 300 is axially polarized +Z, and the compensating piezoelectric ceramic is radially polarized +X / Y), precise suppression of non-target modal vibrations can be achieved. Specifically, a radial high-voltage electric field is first used to orthogonally polarize the compensating piezoelectric ceramic, giving it a transverse piezoelectric effect. Then, the compensating piezoelectric ceramic is placed at the antinodes of the radial vibration mode of the stacked main piezoelectric ceramics 300. A signal of the same frequency and out of phase (180° phase difference) with the main piezoelectric ceramic 300 is applied through an independent driving channel. The resulting reverse strain cancels out residual radial vibration. Finally, combined with real-time feedback from a laser vibrometer, a PID algorithm is used to dynamically adjust the amplitude of the compensating driving voltage, forming a closed-loop control. This application, through the synergistic effect of orthogonal polarization, spatial layout optimization, and active control, can improve the radial vibration suppression rate to over 75%, while maintaining the purity of axial vibration >95%.

[0103] The principle of orthogonal polarization directions: piezoelectric effect directionality: axial polarization (+Z): mainly excites longitudinal vibration ( Effect, strain along the Z-axis). Radial polarization (+X / Y): primarily excites shear or bending vibrations ( Effect, strain perpendicular to the Z-axis). Orthogonal purpose: To compensate for the residual radial vibration by compensating for the strain generated by the piezoelectric ceramic through radial polarization, which is orthogonal to the 300 vibration mode of the main piezoelectric ceramic.

[0104] The process of achieving orthogonal polarization direction: Select radially polarizable piezoelectric ceramic rings or rectangular plates (such as PZT-5H, which supports multi-directional polarization) as compensating piezoelectric ceramics. (1) Radial polarization method: Electrode design: Coat electrodes on the inner and outer walls of the piezoelectric ceramic ring (or the upper and lower surfaces of the rectangular plate). Polarization electric field: Axial polarization (main piezoelectric ceramic 300): The electric field is along the thickness direction (Z-axis). Radial polarization (compensating piezoelectric ceramic): The electric field is polarized radially (X / Y axis, applied through inner and outer electrodes). Polarization parameters: Electric field strength: 2kV / mm~4 kV / mm (same as axial polarization). Temperature: 120℃~150℃ (below the Curie point). (2) Layout of compensating piezoelectric ceramic: Installed at the antinodes of the radial vibration mode of the main piezoelectric ceramic 300 stack (such as the maximum displacement point of the bending vibration mode of a broach). Mechanical coupling: Bonded with epoxy resin to ensure strain transfer efficiency. (3) Drive circuit design: Independent drive channel: The compensating piezoelectric ceramic needs to be driven in a time-sharing or out-of-phase manner with the main piezoelectric ceramic 300. The compensation power supply frequency of the compensating piezoelectric ceramic is the same as the main power supply frequency of the main piezoelectric ceramic 300 but with a phase difference of 180° (or adjusted according to the mode). High voltage isolation: to avoid crosstalk between the drive signals of the main piezoelectric ceramic 300 and the compensating piezoelectric ceramic.

[0105] This application employs a multi-channel signal generator or FPGA to control the phase in real time, ensuring that the compensation power supply frequency of the compensating piezoelectric ceramic is the same as the main power supply frequency of the main piezoelectric ceramic 300, but with a phase difference of 180°. The compensation drive voltage amplitude of the compensating piezoelectric ceramic... Must meet: ,in Radial amplitude, is the strain coefficient of the piezoelectric ceramic.

[0106] The compensation drive voltage was calibrated experimentally. The specific calibration process was as follows: using a Doppler laser vibration meter, the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude was measured when the main piezoelectric actuator device generated ultrasonic high-frequency vibration under the main drive voltage. The driving voltage of the compensation piezoelectric actuator device was successively 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times, and 1 times the main drive voltage. Multiple ratios were obtained, and the driving voltage corresponding to the ratio less than or equal to the preset threshold was taken as the compensation drive voltage.

[0107] In some embodiments, the preset threshold is 5%, meaning that the driving voltage corresponding to a ratio of radial ultrasonic vibration amplitude to axial ultrasonic vibration amplitude of less than or equal to 5% is determined as the compensation driving voltage. It should be noted that if multiple driving voltages correspond to a ratio of radial ultrasonic vibration amplitude to axial ultrasonic vibration amplitude of less than or equal to the preset threshold, the driving voltage corresponding to the smallest ratio is selected as the compensation driving voltage.

[0108] It should be noted that the magnitude of the driving voltage and the specific value of the preset threshold mentioned above should not be regarded as limitations on this application.

[0109] By setting up a compensating piezoelectric actuator device, the ultrasonic broach 200 can be systematically made to achieve pure axial vibration under high pressure load, which significantly improves the machining accuracy and tool life of ultrasonic vibration broaching.

[0110] In some embodiments of this application, the target preload between the main piezoelectric actuator device and the ultrasonic broach 200 is the preload corresponding to the difference between the axial ultrasonic vibration amplitude and the radial ultrasonic vibration amplitude of the ultrasonic broach 200 under the target broach vibration mode, which is the upper limit boundary value of the difference. By setting the target preload between the main piezoelectric actuator device and the ultrasonic broach 200 to the preload corresponding to the difference between the axial ultrasonic vibration amplitude and the radial ultrasonic vibration amplitude of the ultrasonic broach 200 under the target broach vibration mode, the axial ultrasonic vibration amplitude can be increased and the radial ultrasonic vibration amplitude can be decreased, thereby improving machining accuracy and efficiency.

[0111] In some embodiments, the minimum preload is 50N, the maximum is 500N, and the increment is 50N. The ultrasonic vibration amplitude is measured in sequence. The preload corresponding to the largest difference between the axial ultrasonic vibration amplitude and the radial ultrasonic vibration amplitude is determined as the target preload. This can increase the axial ultrasonic vibration amplitude and decrease the radial ultrasonic vibration amplitude, thereby improving processing accuracy and efficiency.

[0112] In some embodiments of this application, the ultrasonic broach 200 is further provided with a counterweight structure, which is located at a position symmetrical to the main piezoelectric actuator device and the compensating piezoelectric actuator device. When the ultrasonic broach 200 vibrates axially, radial vibration is inevitable. By adding a counterweight at a position symmetrical to the ultrasonic broach 200 and the main piezoelectric actuator device and the compensating piezoelectric actuator device, and adjusting the mass of the broach's symmetrical plane, mass balance is achieved, and bending moment is counteracted, thereby reducing radial ultrasonic vibration.

[0113] According to the ultrasonic assisted broaching machine tool based on resonant broach of the present application embodiment, the present application greatly reduces the structure and number of parts of the ultrasonic device by setting a main piezoelectric actuator device on the ultrasonic broach 200 and using the broach as the ultrasonic vibration amplitude rod 400, so as to meet the requirements of frequent broach assembly. However, using the broach as the ultrasonic vibration amplitude rod 400 will generate ultrasonic axial and radial vibrations. The radial ultrasonic vibration amplitude will significantly reduce the dimensional accuracy of broaching. It is necessary to increase the axial ultrasonic vibration amplitude as much as possible and reduce the radial ultrasonic vibration amplitude. This application improves machining accuracy and efficiency by setting the main power supply frequency of the main piezoelectric actuator to the frequency corresponding to the upper limit of the axial ultrasonic vibration amplitude and the lower limit of the radial ultrasonic vibration amplitude under different power supply frequencies. It determines the main driving voltage of the main piezoelectric actuator based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. Furthermore, it sets a compensation piezoelectric actuator at the position corresponding to the radial vibration mode of the ultrasonic broach 200, and controls the polarization direction of the compensation piezoelectric actuator to be orthogonal to the polarization direction of the main piezoelectric actuator. The compensation driving voltage is set to the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator generates high-frequency ultrasonic vibration under the main driving voltage.

[0114] The following will combine Figures 1 to 3 The design method of ultrasonic-assisted broaching machine tool based on resonance broaching tool according to the embodiments of this application is clearly and completely described. Obviously, the embodiments described below are some embodiments of this application, not all embodiments.

[0115] The design method of the ultrasonic-assisted broaching machine tool based on a resonant broach according to the second aspect of this application, applied to the ultrasonic-assisted broaching machine tool based on a resonant broach according to the first aspect of the present application, includes:

[0116] Acquire the positions of the baffle mode peaks and the radial vibration modes on the ultrasonic baffle 200.

[0117] The main piezoelectric actuator is positioned at the position corresponding to the peak of the ultrasonic broach 200, and the compensating piezoelectric actuator is positioned at the position corresponding to the radial vibration mode on the ultrasonic broach 200.

[0118] The ultrasonic power supply is controlled to generate a target broach vibration mode on the main piezoelectric actuator device, so as to excite the ultrasonic broach 200 to generate ultrasonic high-frequency vibration. The target broach vibration mode is generated under the main power supply frequency and the main driving voltage. The main power supply frequency is the frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value under different power supply frequencies. The main driving voltage is determined according to the main power supply frequency, the preset maximum broaching speed and the ultrasonic-assisted broaching effectiveness coefficient.

[0119] The ultrasonic power supply is controlled to generate a compensating broach vibration mode for the compensated piezoelectric actuator device, so as to symmetrically compensate for the radial vibration generated by the ultrasonic broach 200. The compensating broach vibration mode is generated under the compensating power supply frequency and the compensating driving voltage. The compensating power supply frequency is the same as the main power supply frequency, but the phase difference is 180°. The compensating driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude of the compensated piezoelectric actuator device being less than or equal to a preset threshold when the ultrasonic high-frequency vibration is generated by the main driving voltage.

[0120] It is understood that the ultrasonic-assisted broaching machine tool of this application is based on the traditional broaching machine tool, except that the traditional broach is replaced with the ultrasonic broach 200 of this application. Except for the ultrasonic broach 200, the other structures are consistent with the structure of the traditional broaching machine tool. The basic working principle and working process of the broaching machine tool will not be described in detail here.

[0121] refer to Figure 1 This application significantly reduces the structure and number of parts of the ultrasonic device by setting a main piezoelectric actuator device on the ultrasonic broach 200 and using the broach as the ultrasonic vibration amplitude transformer 400, thus meeting the requirements of frequent broach assembly. However, using the broach as the ultrasonic vibration amplitude transformer 400 will generate ultrasonic axial and radial vibrations. The radial ultrasonic vibration amplitude will significantly reduce the dimensional accuracy of broaching. It is necessary to increase the axial ultrasonic vibration amplitude as much as possible and reduce the radial ultrasonic vibration amplitude.

[0122] It should be noted that, Figure 1 The ultrasonic vibration amplitude transformer 400 in this application is equivalent to the corresponding structure of the main piezoelectric actuator device and is part of the ultrasonic baffle 200. In other words, the ultrasonic vibration amplitude transformer 400 and the ultrasonic baffle 200 in this application are the same structure.

[0123] In some embodiments of this application, the main piezoelectric actuator device includes four main piezoelectric ceramics 300, corresponding to four grooves, which are embedded in the grooves of the ultrasonic baffle 200. The ultrasonic power supply converts conventional power into ultrasonic power, and the main piezoelectric ceramics 300, under the action of the ultrasonic power supply, become piezoelectric actuators, exciting the ultrasonic vibration amplitude transformer 400, i.e., the ultrasonic baffle 200, to generate high-frequency ultrasonic vibration. The main piezoelectric ceramics 300 are installed at positions corresponding to the peaks of the baffle's vibration mode, with the primary goal of exciting axial vibration.

[0124] In some embodiments of this application, the main piezoelectric actuator device includes four main piezoelectric ceramics 300, which are stacked symmetrically in a ring, with adjacent main piezoelectric ceramics 300 having opposite polarization directions. The four main piezoelectric ceramics 300 are symmetrically arranged along the axis of the ultrasonic broach 200, with their polarization directions aligned with the axial direction. This partitioning of the four main piezoelectric ceramics 300, with adjacent main piezoelectric ceramics 300 employing opposite polarization, enhances the uniformity of axial strain.

[0125] Polarization is the process by which piezoelectric ceramics align their domains in a directional manner under a high-voltage electric field, giving them the piezoelectric effect. Adjacent main piezoelectric ceramics 300 adopt reverse polarization (+ / - alternation) which means that the polarization directions of two adjacent main piezoelectric ceramics 300 are opposite (the polarization direction of one main piezoelectric ceramic 300 is +Z, and the polarization direction of the other main piezoelectric ceramic 300 is -Z).

[0126] The process of achieving reverse polarization is as follows: Four unpolarized main piezoelectric ceramics 300 of uniform size are selected. The main piezoelectric ceramics 300 are placed in a high-voltage electric field (usually 2kV / mm~4kV / mm), and the temperature is raised to slightly below the Curie point (e.g., 150℃). Forward polarization (+Z): the upper electrode is connected to a positive high voltage, and the lower electrode is grounded; reverse polarization (-Z): the upper electrode is grounded, and the lower electrode is connected to a positive high voltage; alternating arrangement: when stacked, the polarization directions of adjacent main piezoelectric ceramics 300 are opposite. The same-oriented electrodes of all main piezoelectric ceramics 300 (e.g., the +Z surface) are connected in parallel to the positive terminal of the ultrasonic power supply, and the -Z surface is connected in parallel to the negative terminal of the ultrasonic power supply. The actual electric field directions of adjacent main piezoelectric ceramics 300 are the same (both from top to bottom).

[0127] The principle behind reverse polarization enhancing axial strain uniformity is as follows: the axial strain of the main piezoelectric ceramic 300... Determined by the piezoelectric equation: ,in, It represents the longitudinal piezoelectric constant (with opposite signs for +Z and -Z polarization). Indicates the direction of the applied electric field (determined by the polarity of the driving voltage). If the polarization directions of adjacent main piezoelectric ceramics 300 are opposite ( The signs are opposite, but the electric field directions are also opposite (because the electrodes are reversed), so the strain directions are the same (negative times negative equals positive). For example, the first main piezoelectric ceramic 300 (+Z polarization): down (Elongation). Second main piezoelectric ceramic 300 (-Z polarization): up (Similar elongation). If all the main piezoelectric ceramics 300 have the same polarization direction, the electric field directions of adjacent main piezoelectric ceramics 300 will be opposite during series driving, causing one to elongate and the other to shorten, resulting in overall strain cancellation. Advantages of reverse polarization: By reversing the polarization direction and the electric field direction, the strain direction of all main piezoelectric ceramics 300 is ensured to be consistent, and the total displacement is greatly increased after superposition.

[0128] It should be noted that the number of main piezoelectric ceramics 300 can also be eight or other even numbers, and they are also stacked in a ring symmetrical manner. The polarization directions of two adjacent main piezoelectric ceramics 300 are opposite. The specific number of main piezoelectric ceramics 300 mentioned above should not be regarded as a limitation of this application.

[0129] In some embodiments of this application, the target broach vibration mode and the compensated broach vibration mode are obtained through the following steps:

[0130] Acquire the position information of the main piezoelectric actuator device, the material parameters of the ultrasonic broach 200, and the preset initial preload;

[0131] A three-dimensional model of the broach is established based on the location information, material parameters, and preset initial preload.

[0132] Based on the three-dimensional model of the broach, modal simulations of different broach vibration modes under different power supply frequencies were performed. The frequencies corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value were extracted from all broach vibration modes and used as the main power supply frequency.

[0133] The main drive voltage is determined based on the main power frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient.

[0134] The compensation power frequency is determined based on the main power frequency. The compensation power frequency has the same magnitude as the main power frequency, but the phase difference is 180°.

[0135] When measuring the ultrasonic high-frequency vibration generated by the main piezoelectric actuator device under the main driving voltage, the radial ultrasonic vibration amplitude and axial ultrasonic vibration amplitude of the piezoelectric actuator device under different driving voltages are compensated. The driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude is less than or equal to a preset threshold is selected as the compensation driving voltage.

[0136] The target broach vibration mode is generated based on the main power supply frequency and the main drive voltage, and the compensated broach vibration mode is generated based on the compensated power supply frequency and the compensated drive voltage.

[0137] In some embodiments of this application, reference is made to Figure 1 and Figure 2 A three-dimensional model of the broach is established based on the location information, material parameters, and preset initial preload, including:

[0138] The position information, material parameters, and preset initial preload are input into the finite element model, and boundary conditions are set to simulate the actual clamping state. The simulation is performed to obtain the three-dimensional model of the broach. The actual clamping state represents the clamping state of the ultrasonic broach 200 and the clamping body 100. The clamping point between the ultrasonic broach 200 and the clamping body 100 is the broach vibration mode node.

[0139] The location information includes the quantity and position of the main piezoelectric ceramics 300. The material parameters of the ultrasonic broach 200 are high-speed steel or cemented carbide.

[0140] like Figure 2 As shown, the nodes of the broach vibration mode are the nodes where the vibration amplitude is 0 in the broach vibration mode, because the broach vibration mode is a sine wave or a cosine wave. Figure 2 The position connecting the center and the Z-axis is the node of the broach vibration mode, with a vibration amplitude of 0. The broach vibration mode is obtained through modal analysis finite element calculation, thus yielding the node.

[0141] During modal simulation, the broach working condition is referenced, constraints are applied, and modal analysis is performed. The first 100 modes can be calculated. The axial resonant frequency (e.g., 20kHz) is selected as the interval, avoiding the mode shape of the adjacent radial mode. The axial (longitudinal) and radial (bending / torsion) natural frequencies and mode shapes of all broach vibration modes are extracted. The frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value of the axial mode and the radial ultrasonic vibration amplitude being the lower limit boundary value of the radial mode (i.e., the axial ultrasonic vibration amplitude is the largest and the radial ultrasonic vibration amplitude is the smallest) is selected as the main power supply frequency.

[0142] In some embodiments of this application, the constraint formula for the main drive voltage is:

[0143] ;Formula (1)

[0144] ;Formula (2)

[0145] in, The preset maximum broaching speed, The preset ultrasonic-assisted broaching effectiveness coefficient, The amplitude of ultrasonic vibration. Main power supply frequency, The main driving voltage.

[0146] The maximum broaching speed is generally related to the machine tool and is provided by the manufacturer, but there is a general range in the industry, which is usually 5m / min to 15m / min.

[0147] The effectiveness coefficient of ultrasonic-assisted broaching can be determined through orthogonal right-angle ultrasonic cutting experiments, by detecting changes in the cutting force during broaching. The value of is determined as follows:

[0148] (1) Turn on the ultrasonic power supply, assuming a rated power of 300W. Measure the ultrasonic vibration amplitude when the power is 50% using a Doppler laser vibrometer, and record it as follows: The main power supply frequency is By conducting orthogonal right-angle ultrasonic cutting experiments at different cutting speeds (e.g., with ultrasonic assistance) and comparing the cutting forces at different cutting speeds with and without ultrasonic assistance, it was determined that ultrasonic assistance failed when the ultrasonic-assisted cutting force exceeded 90% of the conventional cutting force (when the ultrasonic cutting force approached 80% of the conventional cutting force, ultrasonic assistance failed to reduce the cutting force and thus could not improve cutting performance; only when the cutting force was reduced could cutting performance be improved). The cutting speed under this ultrasonic-assisted cutting force was identified as the critical cutting speed. 1.

[0149] (2) Continue measuring the ultrasonic power supply at 40%, 30%, 20%, and 10% power as described above, and obtain the corresponding values. 2. 3. 4. 5. Considering the effectiveness of ultrasonic vibration at all power levels, 1. 2. 3. 4. The minimum value in 5 is determined as the final value. .

[0150] In some embodiments, under a cutting load of 10 tons, the maximum broaching speed is 15 m / min. It equals 0.377. The value of the main drive voltage can be calculated according to formula (1) and formula (2).

[0151] In some embodiments of this application, when residual radial vibration still exists in the ultrasonic broach 200 with a symmetrical main piezoelectric ceramic 300 layout, it indicates that there is leakage of excitation energy in non-axial modes (such as bending or torsion). This application provides symmetrical compensation by setting a compensating piezoelectric actuator device at the position corresponding to the radial vibration mode of the ultrasonic broach 200, generating a counteracting torque or displacement, thereby neutralizing the radial vibration component. The radial vibration suppression condition must satisfy: the sum of the radial component generated by the main piezoelectric actuator device and the reverse radial component generated by the compensating piezoelectric actuator device is approximately equal to 0.

[0152] First, radial vibration measurement and modal identification experiments were conducted. An ultrasonic power supply generated the target broach vibration mode in the main piezoelectric actuator device to excite the ultrasonic broach 200 to produce high-frequency ultrasonic vibration. A laser Doppler vibrometer was used to scan the surface of the ultrasonic broach 200 to obtain the distribution of axial and radial ultrasonic vibration amplitudes. The vibration spectrum was analyzed using Fast Fourier Transform to identify the dominant frequency of radial vibration (e.g., bending mode frequency). Modal decomposition: If the radial vibration is a first-order bending mode, it manifests as the broach's ends oscillating in opposite directions; if it is a torsional mode, it manifests as the cross-section rotating around its axis.

[0153] The compensated piezoelectric actuator device is constructed in the form of a compensating piezoelectric ceramic. Based on the main piezoelectric ceramic 300 (symmetrically arranged), a compensating piezoelectric ceramic is added at the position corresponding to the radial vibration mode (e.g., at the antinode of the first-order bending mode). If the antinode of the first-order bending mode is located at 1 / 4 and 3 / 4 of the length of the ultrasonic broach 200, then the compensating piezoelectric ceramic is attached there. The polarization direction of the compensating piezoelectric ceramic is orthogonal to that of the main piezoelectric ceramic 300 (e.g., the main piezoelectric ceramic 300 is axially polarized, and the compensating piezoelectric ceramic is radially polarized).

[0154] By designing the polarization direction of the compensating piezoelectric ceramic to be orthogonal to the main piezoelectric ceramic 300 (e.g., the main piezoelectric ceramic 300 is axially polarized +Z, and the compensating piezoelectric ceramic is radially polarized +X / Y), precise suppression of non-target modal vibrations can be achieved. Specifically, a radial high-voltage electric field is first used to orthogonally polarize the compensating piezoelectric ceramic, giving it a transverse piezoelectric effect. Then, the compensating piezoelectric ceramic is placed at the antinodes of the radial vibration mode of the stacked main piezoelectric ceramics 300. A signal of the same frequency and out of phase (180° phase difference) with the main piezoelectric ceramic 300 is applied through an independent driving channel. The resulting reverse strain cancels out residual radial vibration. Finally, combined with real-time feedback from a laser vibrometer, a PID algorithm is used to dynamically adjust the amplitude of the compensating driving voltage, forming a closed-loop control. This application, through the synergistic effect of orthogonal polarization, spatial layout optimization, and active control, can improve the radial vibration suppression rate to over 75%, while maintaining the purity of axial vibration >95%.

[0155] The principle of orthogonal polarization directions: piezoelectric effect directionality: axial polarization (+Z): mainly excites longitudinal vibration ( Effect, strain along the Z-axis). Radial polarization (+X / Y): primarily excites shear or bending vibrations ( Effect, strain perpendicular to the Z-axis). Orthogonal purpose: To compensate for the residual radial vibration by compensating for the strain generated by the piezoelectric ceramic through radial polarization, which is orthogonal to the 300 vibration mode of the main piezoelectric ceramic.

[0156] The process of achieving orthogonal polarization direction: Select radially polarizable piezoelectric ceramic rings or rectangular plates (such as PZT-5H, which supports multi-directional polarization) as compensating piezoelectric ceramics. (1) Radial polarization method: Electrode design: Coat electrodes on the inner and outer walls of the piezoelectric ceramic ring (or the upper and lower surfaces of the rectangular plate). Polarization electric field: Axial polarization (main piezoelectric ceramic 300): The electric field is along the thickness direction (Z-axis). Radial polarization (compensating piezoelectric ceramic): The electric field is polarized radially (X / Y axis, applied through inner and outer electrodes). Polarization parameters: Electric field strength: 2kV / mm~4 kV / mm (same as axial polarization). Temperature: 120℃~150℃ (below the Curie point). (2) Layout of compensating piezoelectric ceramic: Installed at the antinodes of the radial vibration mode of the main piezoelectric ceramic 300 stack (such as the maximum displacement point of the bending vibration mode of a broach). Mechanical coupling: Bonded with epoxy resin to ensure strain transfer efficiency. (3) Drive circuit design: Independent drive channel: The compensating piezoelectric ceramic needs to be driven in a time-sharing or out-of-phase manner with the main piezoelectric ceramic 300. The compensation power supply frequency of the compensating piezoelectric ceramic is the same as the main power supply frequency of the main piezoelectric ceramic 300 but with a phase difference of 180° (or adjusted according to the mode). High voltage isolation: to avoid crosstalk between the drive signals of the main piezoelectric ceramic 300 and the compensating piezoelectric ceramic.

[0157] This application employs a multi-channel signal generator or FPGA to control the phase in real time, ensuring that the compensation power supply frequency of the compensating piezoelectric ceramic is the same as the main power supply frequency of the main piezoelectric ceramic 300, but with a phase difference of 180°. The compensation drive voltage amplitude of the compensating piezoelectric ceramic... Must meet: ,in Radial amplitude, is the strain coefficient of the piezoelectric ceramic.

[0158] In some embodiments of this application, when measuring the ultrasonic high-frequency vibration generated by the main piezoelectric actuator device under the main driving voltage, the radial and axial ultrasonic vibration amplitudes of the piezoelectric actuator device under different driving voltages are compensated, and the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold is selected as the compensation driving voltage, including:

[0159] When the main piezoelectric actuator generates ultrasonic high-frequency vibration under the main driving voltage, the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude is obtained when the driving voltage of the compensating piezoelectric actuator is successively 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times and 1 times the main driving voltage.

[0160] The driving voltage corresponding to a ratio less than or equal to a preset threshold is used as the compensation driving voltage.

[0161] In some embodiments, the preset threshold is 5%, meaning that the driving voltage corresponding to a ratio of radial ultrasonic vibration amplitude to axial ultrasonic vibration amplitude of less than or equal to 5% is determined as the compensation driving voltage. It should be noted that if multiple driving voltages correspond to a ratio of radial ultrasonic vibration amplitude to axial ultrasonic vibration amplitude of less than or equal to the preset threshold, the driving voltage corresponding to the smallest ratio is selected as the compensation driving voltage.

[0162] It should be noted that the magnitude of the driving voltage and the specific value of the preset threshold mentioned above should not be regarded as limitations on this application.

[0163] By setting up a compensating piezoelectric actuator device, the ultrasonic broach 200 can be systematically made to achieve pure axial vibration under high pressure load, which significantly improves the machining accuracy and tool life of ultrasonic vibration broaching.

[0164] According to the design method of the ultrasonic-assisted broaching machine tool based on the resonant broach of this application, this application sets a main piezoelectric actuator device on the ultrasonic broach 200 and uses the broach as the ultrasonic vibration amplitude transformer 400, which greatly reduces the structure and number of parts of the ultrasonic device and meets the requirements of frequent broach assembly. However, using the broach as the ultrasonic vibration amplitude transformer 400 will generate ultrasonic axial and radial vibrations. The radial ultrasonic vibration amplitude will significantly reduce the dimensional accuracy of broaching. It is necessary to increase the axial ultrasonic vibration amplitude as much as possible and reduce the radial ultrasonic vibration amplitude. This application improves machining accuracy and efficiency by setting the main power supply frequency of the main piezoelectric actuator to the frequency corresponding to the upper limit of the axial ultrasonic vibration amplitude and the lower limit of the radial ultrasonic vibration amplitude under different power supply frequencies. It determines the main driving voltage of the main piezoelectric actuator based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. Furthermore, it sets a compensation piezoelectric actuator at the position corresponding to the radial vibration mode of the ultrasonic broach 200, and controls the polarization direction of the compensation piezoelectric actuator to be orthogonal to the polarization direction of the main piezoelectric actuator. The compensation driving voltage is set to the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator generates high-frequency ultrasonic vibration under the main driving voltage.

[0165] In some embodiments of this application, the method further includes:

[0166] Under the target broach vibration mode, the axial and radial ultrasonic vibration amplitudes of the ultrasonic broach 200 are obtained corresponding to different preload forces between the main piezoelectric actuator device and the ultrasonic broach 200.

[0167] The difference between the axial and radial ultrasonic vibration amplitudes corresponding to each preload is determined, resulting in multiple differences;

[0168] The preload force corresponding to the upper limit boundary value of the multiple differences is determined as the target preload force between the main piezoelectric actuator device and the ultrasonic broach 200.

[0169] The preload is adjusted by adjusting the fit tolerance at the connection between the main piezoelectric ceramic 300 and the ultrasonic broach 200. Generally, an interference fit is used. The larger the interference, the larger the preload. Adjusting the interference of the fit tolerance ensures the coupling stiffness between the main piezoelectric ceramic 300 and the ultrasonic broach 200 and avoids nonlinear contact.

[0170] In some embodiments, the minimum preload is 50N, the maximum is 500N, and the increment is 50N. The ultrasonic vibration amplitude is measured in sequence. When the difference between the axial ultrasonic vibration amplitude and the radial ultrasonic vibration amplitude is the largest, it is determined as the target preload. This can increase the axial ultrasonic vibration amplitude and reduce the radial ultrasonic vibration amplitude, thereby improving the processing accuracy and efficiency.

[0171] In one specific embodiment, the target preload is 300N, which can avoid contact loss and improve the ultrasonic energy transfer efficiency.

[0172] Additionally, one embodiment of this application provides a control device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor and the memory can be connected via a bus or other means.

[0173] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0174] The non-transient software program and instructions required for obtaining the target broach mode and the compensated broach mode in the design method of the ultrasonic assisted broaching machine tool based on resonant broach in the above embodiments are stored in the memory. When executed by the processor, the method for obtaining the target broach mode and the compensated broach mode in the design method of the ultrasonic assisted broaching machine tool based on resonant broach in the above embodiments is executed.

[0175] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0176] Furthermore, one embodiment of this application provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, such as the processor in the above embodiment, causing the processor to perform the method for obtaining the target broach mode and the compensated broach mode in the design method of the ultrasonic-assisted broaching machine tool based on a resonant broach in the above embodiment.

[0177] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0178] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. An ultrasonic-assisted broaching machine tool based on a resonance broach, characterized in that, include: The broaching machine structure has a tool clamping body and a tool feeding device; An ultrasonic baffle has one end engaged with the baffle body and the other end connected to the baffle delivery device. The ultrasonic baffle has a groove located at the position corresponding to the peak of the baffle's vibration mode. The main piezoelectric actuator device is disposed in the groove; A compensating piezoelectric actuator device is disposed at the position corresponding to the radial vibration mode on the ultrasonic broach, and the polarization direction of the compensating piezoelectric actuator device is orthogonal to the polarization direction of the main piezoelectric actuator device. An ultrasonic power supply is electrically connected to both the main piezoelectric actuator and the compensating piezoelectric actuator. The ultrasonic power supply generates a target broach vibration mode to excite the ultrasonic broach to produce high-frequency ultrasonic vibration, and also generates a compensating broach vibration mode to symmetrically compensate for the radial vibration generated by the ultrasonic broach. The target broach vibration mode is generated at the main power supply frequency and the main driving voltage. The compensating broach vibration mode is generated at the compensating power supply frequency and the compensating driving voltage. The main power supply frequency is the frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value at different power supply frequencies. The main driving voltage is determined based on the main power supply frequency, a preset maximum broaching speed, and an ultrasonic-assisted broaching effectiveness coefficient. The compensating power supply frequency is the same as the main power supply frequency but with a 180° phase difference. The compensating driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold when the main piezoelectric actuator generates high-frequency ultrasonic vibration at the main driving voltage and the compensating piezoelectric actuator operates at different driving voltages.

2. The ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 1, characterized in that, The target preload between the main piezoelectric actuator and the ultrasonic broach is the preload corresponding to the difference between the axial ultrasonic vibration amplitude and the radial ultrasonic vibration amplitude of the ultrasonic broach under the target broach vibration mode, which is the upper limit boundary value of the difference.

3. The ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 1, characterized in that, The ultrasonic broach is also provided with a counterweight structure, which is located at an overall symmetrical position between the main piezoelectric actuator device and the compensating piezoelectric actuator device.

4. The ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 1, characterized in that, The main piezoelectric actuator device includes four main piezoelectric ceramics, which are stacked symmetrically in a ring, with adjacent main piezoelectric ceramics having opposite polarization directions.

5. A design method for an ultrasonic-assisted broaching machine tool based on a resonance broach, characterized in that, The method, applied to an ultrasonic-assisted broaching machine tool based on a resonant broach as described in any one of claims 1 to 4, comprises: Obtain the positions corresponding to the baffle mode peaks and the radial vibration modes on the ultrasonic baffle. The main piezoelectric actuator is positioned at the position corresponding to the peak of the ultrasonic broach vibration mode, and the compensating piezoelectric actuator is positioned at the position corresponding to the radial vibration mode on the ultrasonic broach. The ultrasonic power supply is controlled to generate the target broach vibration mode on the main piezoelectric actuator device to excite the ultrasonic broach to generate ultrasonic high-frequency vibration. The target broach vibration mode is generated under the main power supply frequency and the main driving voltage. The main power supply frequency is the frequency corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value of the axial direction and the radial ultrasonic vibration amplitude being the lower limit boundary value of the radial direction at different power supply frequencies. The main driving voltage is determined according to the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. The ultrasonic power supply is controlled to generate the compensated broach vibration mode of the compensated piezoelectric actuator device to symmetrically compensate for the radial vibration generated by the ultrasonic broach. The compensated broach vibration mode is generated under the compensated power supply frequency and the compensated driving voltage. The compensated power supply frequency is the same as the main power supply frequency but has a phase difference of 180°. The compensated driving voltage is the driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude of the compensated piezoelectric actuator device being less than or equal to a preset threshold when the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage.

6. The design method of the ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 5, characterized in that, The target broach vibration mode and the compensated broach vibration mode are obtained through the following steps: Obtain the position information of the main piezoelectric actuator device, the material parameters of the ultrasonic broach, and the preset initial preload; A three-dimensional model of the broach is established based on the location information, the material parameters, and the preset initial preload. Based on the three-dimensional model of the broach, modal simulations of different broach vibration modes under different power supply frequencies are performed. The frequencies corresponding to the axial ultrasonic vibration amplitude being the upper limit boundary value and the radial ultrasonic vibration amplitude being the lower limit boundary value are extracted from all broach vibration modes and used as the main power supply frequency. The main drive voltage is determined based on the main power supply frequency, the preset maximum broaching speed, and the ultrasonic-assisted broaching effectiveness coefficient. The compensation power frequency is determined based on the main power frequency, and the compensation power frequency has the same magnitude as the main power frequency, with a phase difference of 180°. When the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage, the radial ultrasonic vibration amplitude and axial ultrasonic vibration amplitude of the compensation piezoelectric actuator device under different driving voltages are measured. The driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold is selected as the compensation driving voltage. The target broach vibration mode is generated based on the main power supply frequency and the main drive voltage, and the compensated broach vibration mode is generated based on the compensation power supply frequency and the compensation drive voltage.

7. The design method of the ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 6, characterized in that, The step of establishing a three-dimensional model of the broach based on the position information, the material parameters, and the preset initial preload includes: The position information, material parameters, and preset initial preload are input into the finite element model, and boundary conditions are set to simulate the actual clamping state. The simulation is performed to obtain the three-dimensional model of the broach. The actual clamping state represents the clamping state of the ultrasonic broach and the clamping body. The clamping point between the ultrasonic broach and the clamping body is the broach vibration mode node.

8. The design method of the ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 5, characterized in that, The method further includes: Under the target broach vibration mode, the axial and radial ultrasonic vibration amplitudes of the ultrasonic broach are obtained corresponding to different preload forces between the main piezoelectric actuator device and the ultrasonic broach. The difference between the axial and radial ultrasonic vibration amplitudes corresponding to each preload is determined, resulting in multiple differences; The preload force corresponding to the upper limit boundary value of the multiple differences is determined as the target preload force between the main piezoelectric actuator device and the ultrasonic broach.

9. The design method of the ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 6, characterized in that, When the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage, the radial and axial ultrasonic vibration amplitudes of the compensating piezoelectric actuator device under different driving voltages are measured. The driving voltage corresponding to the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude being less than or equal to a preset threshold is selected as the compensating driving voltage, including: When the main piezoelectric actuator device generates ultrasonic high-frequency vibration under the main driving voltage, the ratio of the radial ultrasonic vibration amplitude to the axial ultrasonic vibration amplitude is measured when the driving voltage of the compensated piezoelectric actuator device is successively 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times and 1 times the main driving voltage, and multiple ratios are obtained. The driving voltage corresponding to a ratio less than or equal to a preset threshold is used as the compensation driving voltage.

10. The design method of the ultrasonic-assisted broaching machine tool based on a resonance broach according to claim 5, characterized in that, The constraint formula for the main drive voltage is: ； ； in, The preset maximum broaching speed, The preset ultrasonic-assisted broaching effectiveness coefficient, The amplitude of ultrasonic vibration. The main power supply frequency, This refers to the main drive voltage.

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