CNC milling machine minimal quantity lubrication spray head control device driven by ultrasonic motor

Abstract

The invention discloses a CNC milling machine minimal quantity lubrication spray head control device driven by an ultrasonic motor, the CNC milling machine minimal quantity lubrication spray head control device driven by the ultrasonic motor comprises an annular rotating table, a linear lifting part and a rotating part, and the annular rotating table drives the linear lifting part connected with the annular rotating table to rotate; the annular rotating table is composed of an annular rotor, an annular motor base, an annular stator and a rotating structure connected with a bearing inner ring, piezoelectric ceramic pieces are evenly distributed on the surface of the annular stator, the polarization direction of the piezoelectric ceramic pieces is the radial direction, and an annular ultrasonic motor is arranged in the annular motor base; the angle adjusting precision of the spray head is improved to + / -0.01 degrees from + / -0.1 degrees in the prior art, the cutting fluid spraying precision is remarkably improved, cutting fluid waste and workpiece machining quality problems caused by spray head angle deviation are reduced, meanwhile, compared with devices of the same type, the size is reduced by about 30%, and the production cost is reduced. The adverse effect on the maximum stroke of the milling machine after the control device is installed can be effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, and in particular to a control device for a micro-lubrication nozzle of a CNC milling machine driven by an ultrasonic motor. Background Art

[0002] In the field of metal processing, traditional machining widely uses a large amount of emulsions, cutting oils, coolants, etc. to cool and lubricate the processing area; however, this cooling and lubrication method has many disadvantages, such as low utilization rate, which leads to a significant increase in processing costs; if the scrapped coolant is not handled properly, it will cause serious pollution to the environment; dry machining technology has emerged as a green and environmentally friendly processing technology. It abolishes the use of cutting fluids while ensuring the processing accuracy of parts and the service life of tools, and has been successfully applied to a variety of mechanical processing processes; but dry machining fails to effectively solve the problem of cooling the cutting area, and is prone to cause adverse consequences such as burns on the workpiece surface and deterioration of surface integrity.

[0003] Minimum lubrication technology has gradually become an inevitable trend to replace traditional cooling and lubrication methods and dry machining technology. It conforms to the concept of green manufacturing and sustainable development. This technology mixes a small amount of lubricating fluid, water and gas with a certain pressure into atomized form and sprays it into the cutting area. The water and high-pressure gas play a cooling role, while the oil lubricates the cutting area and prolongs the tool life. At present, although the research on minimum lubrication technology has made some progress and many designers have designed minimum lubrication systems, there are still many problems in practical applications.

[0004] The connection nozzle of the micro-lubrication device designed in the prior art mostly adopts an ordinary universal pipe joint, and the nozzle is approximately aligned with the milling cutter. However, when the milling machine is processing at a tricky angle such as milling the circumference and deep grooves, the cutting fluid cannot be sprayed around the working point of the milling cutter, resulting in waste of cutting fluid and burns on the workpiece surface. There is no way to achieve continuous tracking and spraying of cutting fluid for milling machine processing. Some designers have designed a nozzle control device that can be continuously tracked, but there are problems such as the large size of the device and the high requirements for the free space of the milling machine. After installation, it will affect the normal operation of some small milling machines.

[0005] An existing multi-degree-of-freedom micro-lubrication intelligent nozzle system for CNC milling machines, disclosed in Patent No. CN108555685B, has the advantages of being structurally compact, easy to operate, precise in oil quantity control, continuously supplying cutting fluid, and convenient to install. Its device includes a peristaltic pump, an air source processor, a gas-liquid joint, an air source air pipe, an input air pipe, an infusion hose, an output liquid hose, a gas-liquid coaxial pipe, a nozzle, and a box body for installing the above components. However, its nozzle control system is composed of a stepper motor and a power transmission mechanism (synchronous belt, ring gear, bearing) in the rotating part, which has the problem of a relatively large volume in the rotating part, occupies a large space during the installation of the milling machine, has a complex mechanism, and may even be unable to be installed for some milling machine mechanisms with a compact structure. Moreover, the synchronous belt in the transmission part is prone to wear and deformation under the action of tension, and needs to be replaced regularly to maintain the control accuracy, increasing the downtime and maintenance cost. Summary of the Invention

[0006] In view of the problems existing in the above multi-degree-of-freedom micro-lubrication intelligent nozzle system for CNC milling machines during use, the present invention is proposed.

[0007] Therefore, the object of the present invention is to provide a micro-lubrication nozzle control device for a CNC milling machine driven by an ultrasonic motor, which solves the above technical problems.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A micro-lubrication nozzle control device for a CNC milling machine driven by an ultrasonic motor, including an annular rotating table, a linear lifting part, and a rotating part, and the annular rotating table drives the linear lifting part connected thereto to rotate.

[0010] Preferably, the annular rotating table is composed of an annular rotor, an annular motor base, an annular stator, and a rotating structure connected to the inner ring of the bearing. Piezoelectric ceramic pieces are evenly distributed on the surface of the annular stator, the polarization direction of the piezoelectric ceramic pieces is radial, and an annular ultrasonic motor is arranged in the annular motor base.

[0011] Preferably, by applying a high-frequency alternating voltage of 20 - 40 kHz, the stator generates high-frequency vibration. The annular stator (103) drives the annular rotor (101) to rotate by relying on the frictional force with the annular rotor (101). The inner part of the annular rotor (101) is grooved to form a bearing structure with the inner ring of the bearing (102). The annular stator is composed of piezoelectric ceramics and a metal ring pasted on it. When a voltage is applied to the piezoelectric ceramics, it will deform (on a small scale). At this time, if a high-frequency alternating traveling wave voltage is applied, the contact point between the annular stator and the rotor will move forward with the deformation, thereby pushing the upper annular stator to move by relying on the frictional force.

[0012] Preferably, the annular rotor is directly connected to the linear lifting part, and by adjusting the frequency and phase difference of the driving signal, precise control with a rotational speed of 0 - 300 rpm and a rotational angle accuracy of ±0.01° is achieved.

[0013] Preferably, the annular ultrasonic motor drive module integrates a magnetic encoder AS5048A to real - time feedback the position of the annular rotor. A displacement sensor detects the position of the linear lifting groove. The small joint motor is embedded with an encoder to output the angle of the rotating robotic arm and the incident angle of the nozzle, forming a closed - loop control.

[0014] Preferably, in the linear lifting part, the stator of the linear ultrasonic motor is installed on the linear track chute, and the linear bearing serves as the mover, which can move linearly in the linear track chute and drive the linear lifting groove to move linearly, and is connected to the rotating part through a connecting joint;

[0015] The linear ultrasonic motor drives the linear bearing to move up and down in the linear track chute.

[0016] Preferably, the rotating robotic arm of the rotating part is connected to the connecting joint of the linear lifting part. A small joint motor is used to connect between the rotating robotic arm and the connecting joint, and a small joint motor is used to connect the end of the rotating robotic arm and the nozzle bracket, for controlling the incident angle of the nozzle.

[0017] Preferably, the spatial position of the nozzle is calculated by the following formula: Let the center of rotation be the origin, the machining position of the milling cutter be (x1, y1, z1), the rotation angle of the rotating part be Φ, the radius be R, the lifting height be h, the length of the lifting rod be m, the rotation angle of the rotating part be θ, and the length be n. Then the spatial position of the nozzle is:

[0018]

[0019] In the above - mentioned technical solution, the technical effects and advantages provided by the present invention are:

[0020] In the present invention, the nozzle angle adjustment accuracy is improved from ±0.1° in the prior art to ±0.01°, significantly improving the accuracy of cutting fluid spraying, reducing the waste of cutting fluid and workpiece machining quality problems caused by nozzle angle deviation. At the same time, the volume is reduced by about 30% compared with the same - type device, and it can effectively avoid the adverse impact on the maximum stroke of the milling machine after the control device is installed;

[0021] The dynamic performance of the present invention is improved: the response time is less than 5 ms, which is significantly shorter than 50 ms of the stepping - motor solution, and can quickly respond to the angle change requirements during the machining process; at the same time, it supports high - frequency micro - amplitude oscillation (such as ±2°@100Hz), can better adapt to complex machining conditions, and ensure that the cutting fluid can always be accurately sprayed around the working point of the milling cutter;

[0022] The volume of the present invention is reduced: After canceling the transmission part of the rotating part (in addition to the type driven by a belt, there is also a type composed of the combination of the x, y, and z axes), the volume of the device is reduced, which is more conducive to installation on a CNC milling machine with a compact structure, does not affect the normal operation of the equipment, improves the space utilization rate of the equipment, and meets the installation requirements of different models of milling machines;

[0023] The energy-saving performance of the present invention is improved: The power consumption is reduced by 70%. The rated power of the stepping motor is 50W, while the rated power of the ultrasonic motor adopted in the present invention is only 15W, effectively reducing the energy consumption and meeting the development requirements of green manufacturing. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of a micro-lubrication nozzle control device for a CNC milling machine driven by an ultrasonic motor proposed by the present invention;

[0026] Figure 2 It is Figure 1 the front view of;

[0027] Figure 3 It is Figure 1 the top view of;

[0028] Figure 4 It is Figure 1 the left view of;

[0029] Figure 5 It is Figure 1 the exploded view of the annular rotating table of;

[0030] Figure 6 It is Figure 5 the three-view drawing of the annular rotor;

[0031] Figure 7 It is Figure 5 the three-view drawing of the inner ring of the bearing;

[0032] Figure 8 It is Figure 5 the two-view drawing of the annular stator;

[0033] Figure 9 It is Figure 5 the two-view drawing of the annular motor base;

[0034] Figure 10 It is Figure 1 the exploded view of the linear lifting part;

[0035] Figure 11 For Figure 1 Exploded view of the rotating part.

[0036] Description of the reference numerals:

[0037] 1. Ring-shaped rotating table; 101. Ring-shaped rotating table; 102. Inner ring of bearing; 103. Ring-shaped stator; 104. Ring-shaped motor base; 2. Linear lifting part; 201. Linear track chute; 202. Linear ultrasonic motor stator; 203. Linear bearing; 204. Linear lifting groove; 205. Connecting joint; 3. Rotating part; 301. Rotating robotic arm; 302. Nozzle bracket; 303. Small joint motor. Detailed implementation manners

[0038] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further introduced in detail below with reference to the accompanying drawings.

[0039] An embodiment of the present invention discloses a micro-lubrication nozzle control device for a CNC milling machine driven by an ultrasonic motor.

[0040] Refer to Figure 1-11 , the micro-lubrication nozzle control device for a CNC milling machine driven by an ultrasonic motor includes a ring-shaped rotating table, a linear lifting part and a rotating part, and the ring-shaped rotating table drives the linear lifting part connected thereto to rotate.

[0041] The ring-shaped rotating table is composed of a ring-shaped rotor, a ring-shaped motor base, a ring-shaped stator and a rotating structure connected to the inner ring of the bearing. Piezoelectric ceramic sheets are evenly distributed on the surface of the ring-shaped stator, the polarization direction of the piezoelectric ceramic sheets is radial, and a ring-shaped ultrasonic motor is arranged in the ring-shaped motor base.

[0042] By applying a high-frequency alternating voltage of 20 - 40 kHz, the stator generates high-frequency vibration. The ring-shaped stator (103) and the ring-shaped rotor (101) drive the ring-shaped rotor (101) to rotate by means of friction. A bearing structure is formed by the inner groove of the ring-shaped rotor (101) and the inner ring of the bearing (102); the ring-shaped stator is composed of piezoelectric ceramics and a metal ring pasted thereon. When a voltage is applied to the piezoelectric ceramics, it will deform (on a small scale). At this time, if a high-frequency alternating traveling-wave voltage is applied, the contact point between the ring-shaped stator and the rotor will move forward with the deformation, thereby pushing the upper ring-shaped stator to move by means of friction.

[0043] The ring-shaped rotor is directly connected to the linear lifting part. By adjusting the frequency and phase difference of the driving signal, precise control with a rotational speed of 0 - 300 rpm and a rotational angle accuracy of ±0.01° is achieved.

[0044] The ring ultrasonic motor drive module integrates the magnetic encoder AS5048A to real-time feedback the position of the ring rotor. The displacement sensor detects the position of the linear lifting groove. The small joint motor is embedded with an encoder to output the angle of the robotic arm and the incident angle of the nozzle, forming a closed-loop control.

[0045] In the linear lifting part, the stator of the linear ultrasonic motor is installed on the linear track chute. The linear bearing serves as the mover and can move linearly in the linear track chute and drive the linear lifting groove to move linearly. It is connected to the rotating part through a connecting joint.

[0046] The linear ultrasonic motor drives the linear bearing to move up and down in the linear track chute.

[0047] The robotic arm of the rotating part is connected to the connecting joint of the linear lifting part. A small joint motor is used to connect between the robotic arm and the connecting joint. A small joint motor is used to connect the end of the robotic arm and the nozzle bracket to control the incident angle of the nozzle.

[0048] The spatial position of the nozzle is calculated by the following formula: Let the center of rotation be the origin, the machining position of the milling cutter be (x1, y1, z1), the rotation angle of the rotating part be Φ, the radius be R, the lifting height be h, the length of the lifting rod be m, the rotation angle of the rotating part be θ, and the length be n. Then the spatial position of the nozzle is:

[0049]

[0050] In the present invention, in practical applications:

[0051] First, install the micro-lubrication nozzle control device of the ultrasonic motor-driven CNC milling machine on the CNC milling machine. After installation, perform the debugging work before operation. First, debug the ring turntable 1. Input drive signals with different frequencies and phase differences through the control system, and observe the rotation speed and rotation angle of the rotating structure connected to the inner ring 102 of the bearing. Utilize the position information real-time feedback by the magnetic encoder AS5048A to check whether the accuracy of the rotation angle can reach ±0.01°, and whether the rotation speed can be accurately controlled within the range of 0 - 300 rpm. If any deviation is found, adjust the parameters of the drive signal until the expected control accuracy is achieved.

[0052] Then, debug the linear lifting part 2. Start the linear ultrasonic motor and observe the linear movement of the linear bearing 203 in the linear lifting groove 204. Check whether its lifting movement is smooth and whether there is any jamming phenomenon. Control the lifting height of the linear bearing 203 through the control system to ensure that it can accurately reach the set height value.

[0053] Finally, debug the rotating part 3. Control the rotation of the small joint motor 303 through the control system, observe the rotation of the rotating robotic arm 301 and the nozzle bracket 302, and check whether the adjustment of the incident angle of the nozzle is accurate and flexible.

[0054] Control during the machining process

[0055] When machining on a CNC milling machine, determine the initial position and angle of the nozzle according to factors such as the machining process requirements, the shape and size of the workpiece, etc.; adjust the drive signal of the annular rotating table 1 through the control system to make the rotating part of the annular rotating table 1 rotate to the appropriate angle Φ, and adjust the rotation speed as needed;

[0056] According to the machining depth of the milling cutter and the height of the workpiece, control the linear ultrasonic motor to drive the linear bearing 203 to move up and down in the linear lifting groove 204, so that the linear lifting part 2 reaches the appropriate lifting height h, and then control the small joint motor 206 of the lifting part to rotate an appropriate angle θ to make the nozzle reach the appropriate spatial position;

[0057] During the machining process, if it is necessary to adjust the incident angle of the nozzle, control the small joint motor 303 of the rotating part 3 to rotate through the control system, so that the nozzle bracket 302 rotates to the appropriate angle, thereby accurately controlling the incident angle of the nozzle and ensuring that the cutting fluid can be accurately sprayed around the working point of the milling cutter;

[0058] During the entire machining process, the magnetic encoder AS5048A monitors the position of the rotating structure connected to the inner ring 102 of the bearing in real time, the displacement sensor detects the lifting height h, the joint motor embedded encoder outputs the angle θ and the incident angle of the nozzle, and feeds the position information back to the control system; the control system adjusts the drive signal in real time according to the feedback information to ensure that the nozzle is always in the set position and angle, realizing closed-loop control and improving the accuracy of nozzle position and angle control.

[0059] Calculation and application of the spatial position of the nozzle

[0060] During the actual machining process, according to the set machining position (x1, y1, z1) of the milling cutter, the rotation angle Φ, radius R of the rotating part of the annular rotating table 1, the lifting height h of the linear lifting part 2, the length m of the linear lifting groove 204, the rotation angle θ of the rotating part 3, and the length n of the rotating robotic arm 301, calculate using the formula:

[0061] The spatial position of the nozzle;

[0062] Feed the calculated spatial position information of the nozzle to the control system. The control system further adjusts the movements of the annular rotating table 1, the linear lifting part 2, and the rotating part 3 based on this information to ensure that the nozzle can accurately spray the cutting fluid to the required position, improving the machining quality and efficiency.

[0063] Maintenance and servicing

[0064] Regularly carry out maintenance and servicing work on the device; check whether the piezoelectric ceramic chips on the surface of the annular stator 103 of the annular rotating table 1 are damaged. If damaged, replace them in a timely manner. Check whether there are sundries in the linear track chute 201 and the linear lifting chute 204 of the linear lifting part 2. If so, clean them in a timely manner to ensure the smooth movement of the linear bearing 203.

[0065] Check the operating conditions of the small joint motor 303 of the rotating part 3, such as the temperature and noise of the motor. If there are any abnormalities, carry out repairs in a timely manner. At the same time, regularly check the various connection parts of the device to ensure firm connections and avoid affecting the normal operation of the device due to looseness.

[0066] It should be understood that the embodiments of the present application are not limited to the precise structures already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the embodiments of the present application is only limited by the appended claims.

[0067] The above-described embodiments only represent several implementation manners of the embodiments of the present application. Their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the embodiments of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the embodiments of the present application.

Claims

1. Ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device, characterized in that: The invention comprises an annular rotating platform (1), a linear lifting part (2) and a rotating part (3), wherein the annular rotating platform (1) drives the linear lifting part (2) connected thereto to rotate.

2. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to claim 1, characterized in that: The annular rotating platform (1) is composed of an annular rotor (101), an annular motor base (104), an annular stator (103) and a rotating structure connected to a bearing inner ring (102); piezoelectric ceramic sheets are evenly distributed on the surface of the annular stator (103); the polarization direction of the piezoelectric ceramic sheets is radial; and an annular ultrasonic motor is arranged in the annular motor base (104).

3. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to claim 2, characterized in that: By applying a high-frequency alternating voltage of 20-40 kHz, the stator generates high-frequency vibration, and the annular stator (103) and the annular rotor (101) drive the annular rotor (101) to rotate by means of friction, and the internal grooves of the annular rotor (101) and the bearing inner ring (102) form a bearing structure.

4. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to claim 2, characterized in that: The annular rotor (101) is directly connected to the linear lifting part (2), and by adjusting the frequency and phase difference of the driving signal, precise control of the rotation speed within the range of 0-300 rpm and the rotation angle accuracy of ±0.01° is achieved.

5. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to claim 4, characterized in that: The ring-shaped ultrasonic motor drive module is integrated with a magnetic encoder to provide real-time feedback of the position of the ring-shaped rotor (101) to form a closed-loop control.

6. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to claim 1, characterized in that: In the linear lifting part (2), the linear ultrasonic motor stator (202) is installed on the linear track slide groove (201), and the linear bearing (203) serves as a mover, which can perform linear motion in the linear track slide groove (201) and drive the linear lifting groove (204) to perform linear motion, and is connected to the rotating part (3) via a connecting joint (205); The linear ultrasonic motor drives the linear bearing (203) to perform lifting motion in the linear rail slide groove (201).

7. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to claim 6, characterized in that: The rotating mechanical arm (301) of the rotating part (3) is connected to the connecting joint (205) of the linear lifting part (2); the rotating mechanical arm (301) and the connecting joint (205) are connected by a small joint motor (206); the end of the rotating mechanical arm (301) is connected to the nozzle bracket (302) by a small joint motor (303) for controlling the incident angle of the nozzle.

8. The ultrasonic motor driven CNC milling machine micro-lubrication nozzle control device according to any one of claims 1 to 7, characterized in that: The spatial position of the nozzle is calculated by the following formula: Assume that the rotation center is the origin, the milling cutter processing position is (x1, y1, z1), the rotation angle of the rotating part is Φ, the radius is R, the lifting height is h, the length of the lifting rod is m, the rotation angle of the rotating part is θ, and the length is n, then the spatial position of the nozzle is:

Images