Inner-cooling type longitudinal-torsional ultrasonic milling cutter

Abstract

The invention relates to an inner-cooling type longitudinal-torsional ultrasonic milling cutter, belongs to the technical field of milling, and solves the technical problem that an existing cooling medium cannot be flexibly adjusted according to different machining stages and cooling requirements of parts. The cutter comprises a cutter handle assembly, a connector assembly, a transducer assembly, a cutter assembly and a cooling flow channel, the connector assembly comprises an outer sleeve and an inner sleeve, the inner sleeve can be movably arranged in the outer sleeve in a penetrating mode to form a first position and a second position to achieve adjustment of a cooling medium path, and when the inner sleeve is located at the first position, the transducer assembly is located at the second position; the cooling medium flows out of the cutter assembly to cool the cutter assembly and the cutting area; and when the inner sleeve is located at the second position, the cooling medium cools the cutter handle assembly and the transducer assembly, so that the position change of the inner sleeve enables the cooling system to have good flexibility and adaptability, and the flowing path and strength of the cooling medium can be rapidly adjusted according to different machining stages and cooling requirements of different parts.

Description

Technical Field

[0001] The present invention relates to the field of milling technology, and in particular to an internal-cooling longitudinal-torsional ultrasonic milling cutter. Background Art

[0002] Composite materials such as titanium alloys and superalloys have excellent properties such as high strength, wear resistance, and corrosion resistance, and have been widely used in fields such as machinery, aerospace, and shipbuilding. Usually, these composite materials are processed into precision parts by milling processes. However, traditional milling processes are inefficient and costly. With the continuous progress of technology, ultrasonic processing technology has emerged. Compared with high-speed milling, longitudinal-torsional ultrasonic milling can achieve the same machining accuracy in a low rotational speed range, and has small cutting forces, which can reduce tool wear and extend the service life of the tool.

[0003] Long-term machining of the tool will cause the overall temperature of the tool to be too high. In related technologies, a flow path of a cooling medium is set in the tool to cool part of the tool. The flow path of the cooling medium is usually fixed and cannot be flexibly adjusted according to different machining stages and the cooling requirements of components. For example, in some machining stages, the tool assembly requires more cooling, while in other stages, the transducer assembly or the tool holder assembly may also require cooling. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide an internal-cooling longitudinal-torsional ultrasonic milling cutter to solve the technical problem that the cooling medium in the prior art cannot be flexibly adjusted according to different machining stages and the cooling requirements of components.

[0005] The object of the present invention is mainly achieved by the following technical solutions: An internal-cooling longitudinal-torsional ultrasonic milling cutter includes a tool holder assembly, a joint assembly, a transducer assembly, a tool assembly, and a cooling channel. The tool holder assembly is connected to the machine tool spindle. The joint assembly is connected between the tool holder assembly and the transducer assembly. The tool assembly is connected to the transducer assembly. The cooling channel penetrates through the tool holder assembly, the joint assembly, the transducer assembly, and the tool assembly; The joint assembly includes an outer sleeve and an inner sleeve. The outer sleeve is arranged between the tool holder assembly and the transducer assembly. The inner sleeve can move through the outer sleeve to form a first position and a second position; The outer sleeve is provided with a first fluid inlet and a first fluid outlet. When the inner sleeve is in the first position, the first fluid inlet is communicated with the inner sleeve to cool the tool assembly; when the inner sleeve is in the second position, the first fluid inlet is communicated with both the inner sleeve and the first fluid outlet to cool the transducer assembly and the tool assembly; The tool assembly is provided with a milling cutter.

[0006] Further, the joint assembly further includes an elastic member disposed between the inner sleeve and the transducer assembly to enable the top end of the inner sleeve to block part of the first inlet.

[0007] Further, the first inlet includes a central inlet and a circumferential inlet formed at the top end of the outer sleeve. When the inner sleeve is in the first position, the top end of the inner sleeve blocks the central inlet. When the inner sleeve is in the second position, the top end of the inner sleeve is away from the central inlet.

[0008] Further, the inner sleeve includes a second inlet and a second outlet that communicate with each other. The second inlet communicates with the first inlet, and the second outlet communicates with the cooling channel.

[0009] Further, the tool shank assembly includes a pull stud, a tool shank body, and a secondary side power supply coil. The pull stud is connected to the machine tool spindle, the tool shank body is connected to the pull stud, and the secondary side power supply coil is disposed on the tool shank body to supply power to the transducer assembly.

[0010] Further, the transducer assembly includes a rear cover plate, a horn, and a piezoelectric ceramic body. The rear cover plate is connected to the joint assembly, the horn is connected to the rear cover plate, and the piezoelectric ceramic is sleeved on the rear cover plate and abuts against the horn.

[0011] Further, the piezoelectric ceramic body includes a plurality of stacked piezoelectric ceramic units. Each piezoelectric ceramic unit includes a piezoelectric ceramic sheet and an electrode sheet disposed on the piezoelectric ceramic sheet.

[0012] Further, a horn flange is provided on the horn, and the horn flange is connected to the tool shank assembly.

[0013] Further, the tool assembly includes a chuck and a fastening nut. The milling cutter is inserted into the chuck, the chuck is assembled in the fastening nut, and the fastening nut is connected to the transducer assembly.

[0014] Further, the milling cutter includes a milling cutter body, a main flow channel, and a branch flow channel. The main flow channel penetrates through the milling cutter body and communicates with the cooling channel. One end of the branch flow channel communicates with the main flow channel, and the other end of the branch flow channel is formed between the side wall and the cutting head of the milling cutter.

[0015] Further, the first inlet communicates between the cooling channel and the inner sleeve.

[0016] Further, the first outlet communicates with the gap between the tool shank assembly and the transducer assembly.

[0017] Furthermore, the cooling channel includes a first cooling channel, a second cooling channel, a third cooling channel, and a fourth cooling channel that are sequentially connected. The first cooling channel penetrates the tool holder assembly, the second cooling channel penetrates the joint assembly, the third cooling channel penetrates the transducer assembly, and the fourth cooling channel penetrates the tool assembly.

[0018] The technical solution of the present invention can at least achieve one of the following effects: (1) In the internal cooling longitudinal-torsional ultrasonic milling cutter of the present invention, the inner sleeve can move within the outer sleeve. Thus, a first position and a second position are generated, thereby controlling the flow path and direction of the cooling medium in the cooling channel. When the inner sleeve is in the first position, the cooling medium enters the inner sleeve through the first flow inlet and then passes through the cooling channel, flowing out from the tool assembly to cool the tool assembly and the cutting area. When the inner sleeve is in the second position, part of the cooling medium enters the inner sleeve through the first flow inlet, and part of the cooling medium enters the gap between the tool holder assembly and the transducer assembly through the first flow inlet and the first flow outlet to cool the two. Thus, the position change of the inner sleeve makes the cooling system have good flexibility and adaptability, and can quickly adjust the flow path and intensity of the cooling medium according to the cooling requirements of different processing stages and different components. (2) In the internal cooling longitudinal-torsional ultrasonic milling cutter of the present invention, the gap between the tool holder assembly and the transducer assembly is close to or opposite to the secondary side power supply coil. The cooling medium flowing through the gap between the tool holder assembly and the transducer assembly directly contacts or approaches the secondary side power supply coil, thereby providing cooling capacity for the secondary side power supply coil. Thus, the temperature of the secondary side power supply coil can be reduced, ensuring its operation within a safe temperature range, which helps to improve the efficiency and reliability of the secondary side power supply coil and extend its service life. (3) In the internal cooling longitudinal-torsional ultrasonic milling cutter of the present invention, the milling cutter includes a milling cutter body, a main flow channel, and branch flow channels. The outlet of the main flow channel inside the milling cutter body is divided into multiple branch flow channels, and the main flow channel communicates with the multiple branch flow channels. The cooling medium can flow to the lateral cutting edges and the processing area, absorb the heat generated during the processing, reduce the temperature of the bottom edge, side edge of the tool, and the processing area. At the same time, the cooling medium can reduce the friction coefficient between the cutting edge and the contact surface of the processing area, reduce the chip adhesion on the cutting edge. Compared with the straight flow channel with the outlet at the bottom of the tool, chips are not easily introduced into the branch flow channels, and no through-hole blockage will occur, which is convenient for maintenance. Thus, it can effectively reduce the cutting temperature, reduce tool wear, extend the tool life, optimize the cutting conditions, reduce the temperature of the cutting area, reduce the thermal deformation of the workpiece and the tool caused by high temperature, and improve the machining accuracy.

[0019] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent specification. Moreover, some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained from the content specifically pointed out in the specification and the drawings. Description of the Drawings

[0020] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation to the present invention. Throughout the drawings, the same reference signs denote the same components. Figure 1 It is a schematic structural diagram of an internal-cooling longitudinal-torsional ultrasonic milling cutter in an embodiment of the present invention. Figure 2 It is a schematic cross-sectional structural diagram of an internal-cooling longitudinal-torsional ultrasonic milling cutter in an embodiment of the present invention. Figure 3 It is Figure 2 an enlarged structural diagram of part A in Figure 4 It is a schematic structural diagram of a transducer assembly in an embodiment of the present invention. Figure 5 It is a schematic structural diagram of a joint assembly in an embodiment of the present invention. Figure 6 It is a schematic diagram of the flow direction of the cooling medium when the inner sleeve is in the first position in an embodiment of the present invention. Figure 7 It is a schematic diagram of the flow direction of the cooling medium when the inner sleeve is in the second position in an embodiment of the present invention. Figure 8 It is a schematic structural diagram of a tool assembly in an embodiment of the present invention. Figure 9 It is a schematic cross-sectional structural diagram of a milling cutter in an embodiment of the present invention. Figure 10 It is a modal analysis diagram of a tool without a spiral groove in the prior art. Figure 11 It is a modal analysis diagram of a tool with a spiral groove (the spiral groove has a reverse helix direction to the cutting edge of the milling cutter) in an embodiment of the present invention. Figure 12 It is a modal analysis diagram of a tool when the spiral groove has the same helix direction as the cutting edge of the milling cutter in an embodiment of the present invention.

[0021] Reference Signs: 1 - Tool shank assembly, 11 - Pull stud, 12 - Tool shank body, 13 - Secondary side power supply coil; 2 - Transducer assembly, 21 - Rear cover plate, 22 - Piezoelectric ceramic body, 221 - Piezoelectric ceramic sheet, 222 - Electrode sheet, 23 - Amplitude transformer, 231 - Amplitude transformer flange, 232 - Conical wall; 3 - Joint assembly, 31 - Outer sleeve, 311 - First fluid inlet, 3111 - Central inlet, 3112 - Circumferential inlet, 312 - First fluid outlet, 32 - Inner sleeve, 321 - Second fluid inlet, 322 - Second fluid outlet, 33 - Elastic member; 4 - Tool assembly, 41 - Fastening nut, 42 - Chuck, 43 - Milling cutter, 431 - Milling cutter body, 432 - Main flow channel, 433 - Branch flow channel; 5 - Cooling channel, 51 - First cooling channel, 52 - Second cooling channel, 53 - Third cooling channel, 54 - Fourth cooling channel. Detailed implementation manners

[0022] The preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The accompanying drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0023] Embodiment 1 A specific embodiment of the present invention discloses an internally cooled longitudinal-torsional ultrasonic milling cutter, as Figure 1 , Figure 2 and Figure 3 shown. The cutter includes a tool shank assembly 1, a joint assembly 3, a transducer assembly 2, a tool assembly 4, and a cooling channel 5. The tool shank assembly 1 is connected to the machine tool spindle. The joint assembly 3 is connected between the tool shank assembly 1 and the transducer assembly 2. The tool assembly 4 is connected to the transducer assembly 2. The cooling channel 5 penetrates through the tool shank assembly 1, the joint assembly 3, the transducer assembly 2, and the tool assembly 4. The joint assembly 3 includes an outer sleeve 31 and an inner sleeve 32. The outer sleeve 31 is arranged between the tool shank assembly 1 and the transducer assembly 2. The inner sleeve 32 can move through the outer sleeve 31 to form a first position and a second position. The outer sleeve 31 is provided with a first fluid inlet 311 and a first fluid outlet 312. When the inner sleeve 32 is in the first position, the first fluid inlet 311 is communicated with the inner sleeve 32 to cool the tool assembly 4. When the inner sleeve 32 is in the second position, the first fluid inlet 311 is communicated with both the inner sleeve 32 and the first fluid outlet 312 to cool the transducer assembly 2 and the tool assembly 4. The tool assembly 4 is provided with a milling cutter 43.

[0024] The tool shank assembly 1 is used to connect with the machine tool spindle. The functions of the tool shank assembly 1 include: receiving power, transmitting the power of the machine tool spindle to the joint assembly 3, providing power support for the ultrasonic vibration of the tool assembly 4 to ensure that the tool assembly 4 can perform effective machining operations; playing a role in supporting the whole tool and shock absorption and buffering. The tool shank assembly 1 can reduce the influence of the vibration of the machine tool spindle on the tool assembly 4 and improve the service life of the tool assembly 4; the joint assembly 3 is used to connect the tool shank assembly 1 and the transducer assembly 2 to ensure their close fit and connection; the transducer assembly 2 is used to convert electrical energy into mechanical energy, generate ultrasonic vibration, and transmit the ultrasonic vibration to the tool assembly 4, making it have the characteristics of longitudinal-torsional composite vibration, thereby improving the cutting performance and machining efficiency of the tool; the tool assembly 4 is used for cutting and machining. It can receive the ultrasonic vibration generated by the transducer assembly 2 to enhance the cutting ability; the cooling channel 5 runs through the whole tool and can convey the cooling medium to the tool shank assembly 1, the joint assembly 3, the transducer assembly 2 and the tool assembly 4 to realize the cooling of the whole tool. The cooling medium takes away the heat generated during the cutting process, reduces the temperature of the tool, reduces the thermal deformation, and improves the service life and machining accuracy of the tool; the cooling medium passes through the tool assembly 4 and sprays to the cutting area, which can play a lubricating role. Thus, the friction coefficient between the tool assembly 4 and the workpiece is reduced, the cutting force is reduced, the wear of the tool is reduced, and at the same time, it also helps to reduce the generation of cutting heat, further improving the machining quality and the service life of the tool; exemplarily, by adjusting the pressure of the cooling medium in the cooling channel 5, the adjustment of the first position and the second position of the inner sleeve 32 in the outer sleeve 31 is realized; exemplarily, the cooling medium can adopt a cooling gas, and this cooling gas should be non-corrosive, specifically such as liquid nitrogen, liquid oxygen, liquid argon, , thereby avoiding liquid entering the inside of the tool shank and contacting the circuit of the transducer to damage the power supply system.

[0025] Specifically, such as Figure 3 , Figure 5 , Figure 6 and Figure 7As shown, the joint assembly 3 includes an outer sleeve 31 and an inner sleeve 32. The outer sleeve 31 is provided with a first fluid inlet 311 and a first fluid outlet 312. The inner sleeve 32 moves within the outer sleeve 31 to generate a first position and a second position, thereby controlling the flow path and direction of the cooling medium in the cooling channel 5. When the inner sleeve 32 is in the first position, the cooling medium enters the inner sleeve 32 through the first fluid inlet 311 and then passes through the cooling channel 5 (the dotted arrows in the figure indicate the flow direction of the cooling medium), flows out through the tool assembly 4, and cools the tool assembly 4 and the cutting area. When the inner sleeve 32 is in the second position, a part of the cooling medium enters the inner sleeve 32 through the first fluid inlet 311, and a part of the cooling medium enters the gap between the tool holder assembly 1 and the transducer assembly 2 through the first fluid inlet 311 and the first fluid outlet 312 to cool the two. Thus, the position change of the inner sleeve 32 makes the cooling system have good flexibility and adaptability, and can quickly adjust the flow path and intensity of the cooling medium according to the cooling requirements of different machining stages and different components, optimize the cooling effect, and improve the cooling performance and machining efficiency of the entire tool system.

[0026] Among them, the first fluid inlet 311 is connected between the cooling channel 5 and the inner sleeve 32 to cool the tool assembly 4, and the first fluid outlet 312 is connected to the gap between the tool holder assembly 1 and the transducer assembly 2 to cool the transducer assembly 2 and the tool assembly 4.

[0027] As Figure 3 shown, the upper end of the outer sleeve 31 is connected to the connecting tool holder assembly 1, and the two can be hermetically connected. The lower end of the outer sleeve 31 is connected to the transducer assembly 2 (for example, by thread), and the two can be hermetically connected. The first fluid outlet 312 is opened at the middle end of the outer sleeve 31. Exemplarily, 6 first fluid outlets 312 are opened at the middle end of the outer sleeve 31; a sealing ring can be provided between the inner sleeve 32 and the outer sleeve 31.

[0028] Furthermore, as Figure 3As shown, the connector assembly 3 also includes an elastic member 33, which is arranged between the inner sleeve 32 and the transducer assembly 2 so that the top of the inner sleeve 32 can block part of the first inlet 311; the elastic member 33 provides a reverse force for the inner sleeve 32, so that the top of the inner sleeve 32 can closely contact and block part of the first inlet 311, so that the inner sleeve 32 is kept in the first position. Specifically, when the transducer assembly 2 generates ultrasonic vibration, the vibration will be transmitted to the inner sleeve 32, and the elastic member 33 can play a role of buffering and stabilization. The inner sleeve 32 can still maintain close contact with the first inlet 311 to achieve sealing during the vibration process, thereby ensuring the stability and controllability of the cooling medium flow path, thereby better controlling the flow direction and flow rate of the cooling medium to achieve cooling and lubrication; when the pressure of the cooling medium in the cooling channel 5 is large enough, the elastic member 33 is compressed to move the inner sleeve 32 downward, and the first inlet 311 is connected to the first outlet 312. At this time, the inner sleeve 32 remains in the second position; illustratively, the elastic member 33 can be a spring.

[0029] Furthermore, if Figure 3 As shown, the first inlet 311 includes a central inlet 3111 and a circumferential inlet 3112 opened at the top of the outer sleeve 31. When the inner sleeve 32 is located at the first position, the top of the inner sleeve 32 is blocked on the central inlet 3111; when the inner sleeve 32 is located at the first position, its top blocks the central inlet 3111. At this time, the cooling medium flows into the inner sleeve 32 through the circumferential inlet 3112. At this time, the cooling medium can give priority to meeting the cooling needs of the tool assembly 4 to ensure that the cutting area is fully cooled and lubricated. After passing through the tool assembly 4, the cooling medium is directly sprayed into the cutting area to take away the heat generated during the cutting process, reduce the friction between the tool and the workpiece, thereby improving the processing quality and the service life of the tool; when the inner sleeve 32 is located at the second position, the top of the inner sleeve 32 is away from the central inlet 3111. At this time, the central inlet 3111 is no longer blocked. The cooling medium can enter the outer sleeve 31 through the central inlet 3111 and the circumferential inlet 3112 at the same time, and the cooling medium enters the annular space between the outer sleeve 31 and the inner sleeve 32 through the central inlet 3111 and the circumferential inlet 3112. In the annular space, a part of the cooling medium enters the gap between the tool handle assembly 1 and the transducer assembly 2 through the first flow outlet 312 (the first flow outlet 312 is opened because the top of the inner sleeve 32 is far away from the central inlet 3111) to cool these components. This design ensures that the tool handle assembly 1 and the transducer assembly 2 can be effectively cooled during operation to prevent performance degradation or damage due to overheating. Another part of the cooling medium still enters through the second flow inlet 321 and flows out from the second flow outlet 322, continuing to flow along the cooling channel 5 to the tool assembly 4 to cool the tool assembly 4 and the cutting area.

[0030] As an improved solution of this embodiment, as Figure 3 shown, the inner sleeve 32 includes a second fluid inlet 321 and a second fluid outlet 322 that are in communication with each other. The second fluid inlet 321 is in communication with the first fluid inlet 311, and the second fluid outlet 322 is in communication with the cooling channel 5. The second fluid inlet 321 is the inlet for the cooling medium to enter the inner sleeve 32, and the second fluid outlet 322 is the outlet for the cooling medium to flow out of the inner sleeve 32. When the inner sleeve 32 is in the first position, the top end of the inner sleeve 32 blocks the central inlet 3111 of the outer sleeve 31, preventing the cooling medium from entering through the central inlet 3111. The cooling medium enters the second fluid inlet 321 of the inner sleeve 32 through the circumferential inlet 3112, and then flows out through the second fluid outlet 322 and enters the cooling channel 5. At this time, the cooling medium mainly flows towards the tool assembly 4 to cool and lubricate the tool assembly 4. When the pressure of the cooling medium increases, the cooling medium pushes the inner sleeve 32 away from the first position to the second position. The cooling medium can enter the second fluid inlet 321 and the first fluid outlet 312 of the inner sleeve 32 through the central inlet 3111 and the circumferential inlet 3112 simultaneously, and then enters the gap between the cooling channel 5, the tool holder assembly 1, and the transducer assembly 2.

[0031] As an improved solution of this embodiment, as Figure 1 shown, the tool holder assembly 1 includes a pull stud 11, a tool holder body 12, and a secondary power supply coil 13. The pull stud 11 is connected to the machine tool spindle, the tool holder body 12 is connected to the pull stud 11, and the secondary power supply coil 13 is arranged on the tool holder body 12 to supply power to the transducer assembly 2. The pull stud 11, as a connecting piece, is used to connect the tool holder body 12 to the machine tool spindle, enabling the tool holder assembly 1 to be stably installed on the machine tool. The tool holder body 12 serves to connect between the pull stud 11 and the joint assembly 3 and provides mechanical support for the tool holder assembly 1. Exemplarily, the tool holder body 12 can adopt a BT40 (type of tool holder) tool holder. The secondary power supply coil 13 transmits electrical energy to the transducer assembly 2 through electromagnetic induction or other means, enabling the transducer assembly 2 to generate ultrasonic vibrations. Exemplarily, the tool holder body 12 can be in the shape of a frustum of a cone, the pull stud 11 is connected to the top end of the tool holder body 12, and the secondary power supply coil 13 is arranged at the bottom end of the tool holder body 12.

[0032] On this basis, the gap between the tool handle assembly 1 and the transducer assembly 2 is close to or facing the secondary side power supply coil 13 to provide cooling capacity for the secondary side power supply coil 13; thus, the cooling medium flows through the gap between the tool handle assembly 1 and the transducer assembly 2 and directly contacts or approaches the secondary side power supply coil 13, thereby providing cooling capacity for the secondary side power supply coil 13. During the process of powering the transducer assembly 2, the secondary side power supply coil 13 will generate heat. If the heat cannot be dissipated in time, it will affect the performance and service life of the secondary side power supply coil 13, and further affect the normal operation of the entire tool system. By allowing the cooling medium to flow through the gap, the temperature of the secondary side power supply coil 13 can be reduced to ensure that it operates within a safe temperature range. This helps to improve the efficiency and reliability of the secondary side power supply coil 13, extend its service life, and at the same time ensures that the transducer assembly 2 can stably receive power and maintain the normal generation and transmission of ultrasonic vibration, thus ensuring the normal operation of the tool.

[0033] As an improved solution of this embodiment, as Figure 2 and Figure 4 shown, the transducer assembly 2 includes a rear cover plate 21, a horn 23, and a piezoelectric ceramic body 22. The rear cover plate 21 is connected to the joint assembly 3, the horn 23 is connected to the rear cover plate 21, and the piezoelectric ceramic body 22 is sleeved on the rear cover plate 21 and abuts against the horn 23.

[0034] The rear cover plate 21 is connected between the joint assembly 3 and the horn 23, playing a role of mechanical support. In addition, the rear cover plate 21 also provides a certain sealing performance to prevent external impurities or cooling medium from entering the interior of the transducer assembly 2. The connection between the rear cover plate 21 and the horn 23 provides an appropriate pre-tightening force to maintain the overall stiffness, resonant frequency, and working impedance stability of the transducer assembly 2; the main function of the horn 23 is to transmit and amplify the ultrasonic vibration generated by the piezoelectric ceramic body 22, amplify the tiny vibration of the piezoelectric ceramic body 22, and transmit it to the tool assembly 4, thereby enhancing the cutting ability of the tool. Moreover, the horn 23 can also adjust the impedance of the vibration system to better match it with the tool assembly 4, improve the energy transfer efficiency, and ensure that the ultrasonic vibration can be effectively applied to the cutting process; through the cooperation of the rear cover plate 21, the horn 23, and the piezoelectric ceramic body 22, ultrasonic vibration is achieved, reducing the friction and cutting force during the cutting process, reducing the generation of cutting heat, thereby improving the cutting efficiency and the quality of the machined surface. In addition, combined with the gap between the tool handle assembly 1 and the transducer assembly 2, the cooling medium can effectively cool the piezoelectric ceramic body 22 and the horn 23 during operation, preventing performance degradation or damage due to overheating, and improving the reliability and efficiency of the entire system.

[0035] Specifically, the piezoelectric ceramic body 22 includes a plurality of (even number) stacked piezoelectric ceramic units. Each piezoelectric ceramic unit includes a piezoelectric ceramic sheet 221 and an electrode sheet 222 disposed on the piezoelectric ceramic sheet 221. The piezoelectric ceramic sheet 221 has a piezoelectric effect. When an alternating electric field is applied to the piezoelectric ceramic sheet 221, the piezoelectric ceramic sheet 221 will generate mechanical vibrations, and these vibrations can significantly reduce the cutting force and cutting heat. The electrode sheet 222 is disposed on the piezoelectric ceramic sheet 221 for applying an electric field. Exemplarily, the electrode sheet 222 can be made of a conductive material and can uniformly apply the electric field to the piezoelectric ceramic sheet 221 to ensure that the piezoelectric ceramic sheet 221 can effectively generate vibrations. Through the design of the stacked piezoelectric ceramic units, the piezoelectric ceramic body 22 can provide powerful ultrasonic vibration energy for the ultrasonic tool, which can significantly improve the cutting performance of the tool and meet the requirements of high-efficiency precision machining.

[0036] Further, a horn flange 231 is provided on the horn 23, and the horn flange 231 is connected to the tool handle assembly 1.

[0037] The horn flange 231 is used to connect the horn and the tool handle assembly. By means of mechanical connection (such as threaded connection, welding or riveting, etc.), the horn 23 is firmly fixed on the tool handle assembly 1 to reduce the energy loss and vibration attenuation during the vibration transmission process, improve the cutting efficiency and machining quality of the tool. In addition, it also helps to reduce the wear and fatigue between components and extend the service life of the horn, the tool handle assembly and the entire ultrasonic tool system.

[0038] Further, the cooling channel 5 includes a first cooling channel 51, a second cooling channel 52, a third cooling channel 53 and a fourth cooling channel 54 that are sequentially connected. The first cooling channel penetrates through the tool handle assembly, the second cooling channel penetrates through the joint assembly, the third cooling channel penetrates through the transducer assembly, and the fourth cooling channel penetrates through the tool assembly.

[0039] Embodiment 2 In Embodiment 2 of the present invention, on the basis of Embodiment 1, the tool assembly 4 is further improved, as Figure 8 shown, the tool assembly 4 includes a chuck 42 and a fastening nut 41. The milling cutter 43 is inserted into the chuck 42, the chuck 42 is assembled in the fastening nut 41, and the fastening nut 41 is connected to the transducer assembly 2.

[0040] The chuck 42 is used to fix the milling cutter 43. It firmly clamps the milling cutter 43 therein through an internal clamping structure (such as a spring collet, a wedge collet, etc.), ensuring that the milling cutter does not loosen during the cutting process. Exemplarily, the chuck 42 adopts an ER (elastic ring) chuck; the fastening nut 41 is used to assemble the chuck 42 on the transducer assembly 2. Exemplarily, the fastening nut 41 adopts an ER fastening nut; the milling cutter 43 is used to cut the cutting area. In addition, the milling cutter 43 also serves as a channel for the cooling medium, introducing the cooling medium into the cutting area to reduce the cutting temperature and improve the machining quality.

[0041] As an improved scheme of this embodiment, as Figure 8 and Figure 9 shown, the milling cutter 43 includes a milling cutter body 431, a main flow channel 432 and branch flow channels 433. The main flow channel 432 penetrates through the milling cutter body 431, and the main flow channel 432 is connected to the cooling flow channel 5. One end of the branch flow channel 433 is connected to the main flow channel 432, and the other end of the branch flow channel 433 is opened between the side wall and the cutting head of the milling cutter 43. Exemplarily, the main flow channel 432 can be linear or spiral. The cross-sectional area of the main flow channel 432 can be circular, and the aperture of the main flow channel can be adjusted as needed. The branch flow channel 433 can be linear, and the aperture of the branch flow channel 433 can also be adjusted as needed. Two branch flow channels 433 can be provided, and both of the two branch flow channels 433 are connected to the main flow channel 432.

[0042] It should be noted that the structure of the milling cutter 43 is not limited to this and can be adjusted according to different processing requirements. For example, by changing the number and position of the branch flow channels 433, the distribution of the cooling medium can be optimized to adapt to different cutting conditions.

[0043] The milling cutter body 431 is the part that directly contacts the workpiece and performs cutting. It has a specific geometric shape and cutting edge and can remove materials with the assistance of ultrasonic vibration. The milling cutter body 431 provides physical support for the cooling medium channel (main channel 432 and branch channel 433) to ensure that the cooling medium can flow smoothly. The main channel 432 can pass through the milling cutter body 431 as a whole or partially, so as to serve as a channel for conveying the cooling medium. It obtains the cooling medium by connecting to the cooling channel 5. The lower end of the main channel 432 is connected with the branch channel 433. Therefore, the main channel 432 also has the function of distributing the cooling medium. By distributing the cooling medium to each branch channel 433, the cooling medium can flow evenly to each cutting area of the milling cutter 43. One end of the branch channel 433 is connected to the main channel 432, and the other end is opened between the side wall and the cutter head of the milling cutter 43, that is, the position of the cutter tip. Therefore, the cooling medium can be directly sprayed into the cutting area to provide cooling and lubrication for the contact part between the cutter head of the milling cutter 43 and the workpiece. In addition, The injection of cooling medium can also reduce cutting force, improve chip discharge, further optimize cutting conditions, and improve processing quality and efficiency. Structurally, the outlet of the main channel 432 inside the milling cutter body 431 is divided into multiple branch channels 433 (for example, two), and the main channel 432 connects multiple branch channels 433. The cooling medium can flow to the lateral blade and the processing area, and can absorb the heat generated during the processing, and reduce the temperature of the bottom blade, side blade and processing area of the tool. At the same time, the cooling medium can reduce the friction coefficient between the blade and the contact surface of the processing area, and reduce the adhesion of chips to the cutting edge. Compared with the straight channel with the outlet at the bottom of the tool, the chips are not easy to enter the branch channel 433, and will not cause blockage of the through hole, which is convenient for maintenance. By coordinating the main channel 432 and the branch channel 433, the cutting temperature can be effectively reduced, the tool wear can be reduced, the tool life can be extended, and the cutting conditions can be optimized. Through effective cooling, the temperature of the cutting area is reduced, the thermal deformation of the workpiece and the tool caused by high temperature is reduced, and the processing accuracy is improved.

[0044] Example 3 In the third embodiment of the present invention, the horn 23 is improved on the basis of the first or second embodiment, such as Figure 1 , Figure 2 and Figure 4 As shown, the amplitude transformer 23 also includes a conical wall 232, on which a plurality of spiral grooves are provided to convert the longitudinal vibration generated by the piezoelectric ceramic body 22 into a longitudinal-torsional composite vibration. Compared with ordinary milling and longitudinal ultrasonic milling, longitudinal-torsional resonance milling has good processing stability, small cutting force, low cutting heat, and can reduce tool wear. Exemplarily, four spiral grooves are provided on the conical wall 232.

[0045] The conical wall 232 is used to transfer the longitudinal vibration generated by the piezoelectric ceramic body 22 to the tool assembly 4. Its conical structure helps to concentrate and amplify the vibration energy, improving the vibration transfer efficiency. The multiple spiral grooves provided thereon are used to achieve longitudinal-torsional composite vibration. When the longitudinal vibration generated by the piezoelectric ceramic body 22 is transferred through the conical wall 232, the spiral grooves will guide the vibration energy to propagate along a spiral path, thereby converting the longitudinal vibration into longitudinal-torsional composite vibration. Thus, the cutting efficiency and machining quality of the tool can be significantly improved. In addition, the spiral grooves can also optimize the distribution of the vibration energy, ensuring that the vibration energy is evenly transferred to each part of the tool assembly 4, which helps to improve the stability and consistency of the cutting process. Through the conical wall 232 and the multiple spiral grooves provided thereon, the longitudinal vibration is converted into longitudinal-torsional composite vibration. During the cutting process, the tool can not only vibrate longitudinally but also generate torsional vibration. This composite vibration mode can more effectively break the material, reduce the generation of cutting force and cutting heat, and significantly improve the cutting efficiency. Moreover, the composite vibration helps to discharge the chips, reducing the adhesion of the chips to the tool and workpiece surfaces, and further optimizing the machining surface quality.

[0046] As an alternative scheme of this embodiment, as Figure 4 , Figure 8 and Figure 9 shown, the helix direction of the spiral groove along the axial direction is the same as the helix direction of the cutting edge of the milling cutter 43.

[0047] When the helix direction of the spiral groove is the same as the helix direction of the cutting edge of the milling cutter 43, the longitudinal-torsional composite vibration transmitted by the horn 23 is consistent with the cutting direction of the milling cutter 43. This synergistic effect enables the tool to more effectively break the material during the cutting process, reducing the generation of cutting force and cutting heat. As Figure 10 , Figure 11 and Figure 12 shown, the colored lines in the figure represent the vibration transfer direction. When there are no spiral grooves on the horn 23, the arrows on the horn 23 and the milling cutter 43 in the simulated velocity vector diagram are transmitted along the z-axis direction, and this is longitudinal vibration at this time. When there are spiral grooves on the horn 23, the arrows on the horn 23 and the milling cutter 43 in the simulated result velocity vector diagram spread spirally at a certain angle, which is a longitudinal-torsional vibration composed of longitudinal vibration (parallel to the z-axis) and torsional vibration (rotating around the z-axis). When the helix direction of the spiral groove is the same as the helix direction of the cutting edge of the milling cutter 43, the amplitude of the torsional vibration output by the tool tip and the torsional-longitudinal ratio (the value of the torsional amplitude divided by the longitudinal amplitude) are larger. When the helix direction of the cutting edge is consistent with the helix direction of the spiral groove, it helps to discharge the chips. The chips will be discharged along the helix direction of the cutting edge during the cutting process, and the design of the spiral groove further optimizes this process, reducing the adhesion of the chips to the tool and workpiece surfaces. The helix direction of the cutting edge being consistent with the helix direction of the spiral groove enables the tool to more evenly bear the cutting force and vibration energy during the cutting process, reducing the local wear of the tool and extending the tool life.

[0048] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An internally cooled longitudinal-torsional ultrasonic milling cutter, characterized in that, It includes a tool shank assembly, a joint assembly, a transducer assembly, a tool component, and a cooling channel. The tool shank assembly is connected to the machine tool spindle. The joint assembly is connected between the tool shank assembly and the transducer assembly. The tool component is connected to the transducer assembly. The cooling channel penetrates through the tool shank assembly, the joint assembly, the transducer assembly, and the tool component; The joint assembly includes an outer sleeve and an inner sleeve. The outer sleeve is arranged between the tool shank assembly and the transducer assembly. The inner sleeve can move through the outer sleeve to form a first position and a second position; The outer sleeve is provided with a first fluid inlet and a first fluid outlet. When the inner sleeve is in the first position, the first fluid inlet is communicated with the inner sleeve to cool the tool component. When the inner sleeve is in the second position, the first fluid inlet is communicated with both the inner sleeve and the first fluid outlet to cool the transducer component and the tool component; The tool component is provided with a milling cutter.

2. The internal cooling type longitudinal-torsional ultrasonic milling cutter according to claim 1, wherein The joint assembly further includes an elastic member. The elastic member is arranged between the inner sleeve and the transducer assembly so that the top end of the inner sleeve can block part of the first fluid inlet.

3. The internal cooling type longitudinal-torsional ultrasonic milling cutter according to claim 2, wherein The first fluid inlet includes a central inlet and a circumferential inlet opened at the top end of the outer sleeve. When the inner sleeve is in the first position, the top end of the inner sleeve blocks the central inlet. When the inner sleeve is in the second position, the top end of the inner sleeve is away from the central inlet.

4. The internal cooling type longitudinal-torsional ultrasonic milling cutter according to claim 1, wherein The inner sleeve includes a second fluid inlet and a second fluid outlet which are communicated with each other. The second fluid inlet is communicated with the first fluid inlet, and the second fluid outlet is communicated with the cooling channel.

5. The internal cooling type longitudinal-torsional ultrasonic milling cutter according to claim 1, wherein, The tool shank assembly includes a pull stud, a tool shank body, and a secondary side power supply coil. The pull stud is connected to the machine tool spindle. The tool shank body is connected to the pull stud. The secondary side power supply coil is arranged on the tool shank body to supply power to the transducer assembly.

6. The internal-cooling longitudinal-torsional ultrasonic milling cutter according to claim 1, wherein The transducer assembly includes a rear cover plate, a horn, and a piezoelectric ceramic body. The rear cover plate is connected to the joint assembly. The horn is connected to the rear cover plate. The piezoelectric ceramic body is sleeved on the rear cover plate and abuts against the horn.

7. The internal cooling type longitudinal-torsional ultrasonic milling cutter according to claim 6, wherein The piezoelectric ceramic body includes a plurality of stacked piezoelectric ceramic units. The piezoelectric ceramic unit includes a piezoelectric ceramic sheet and an electrode sheet arranged on the piezoelectric ceramic sheet.

8. The internal-cooling longitudinal-torsional ultrasonic milling cutter according to claim 6, wherein The horn is provided with a horn flange which is connected to the tool shank assembly.

9. The internal-cooling longitudinal-torsional ultrasonic milling cutter according to claim 1, wherein, The tool component includes a chuck and a fastening nut. The milling cutter is inserted into the chuck. The chuck is assembled in the fastening nut. The fastening nut is connected to the transducer assembly.

10. The internal-cooling longitudinal-torsional ultrasonic milling cutter according to claim 9, characterized in that, The milling cutter includes a milling cutter body, a main flow channel, and a branch flow channel. The main flow channel penetrates through the milling cutter body and is communicated with the cooling channel. One end of the branch flow channel is communicated with the main flow channel, and the other end of the branch flow channel is opened between the side wall and the cutting head of the milling cutter.

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