CN114309696B - A Drilling Device for Measuring Axial Force of Drill Bit Under Ultrasonic Auxiliary Vibration Condition - Google Patents

Abstract

The invention relates to a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic auxiliary vibration, which comprises a machine tool main shaft, a machine tool main shaft shell, a mounting sleeve, a connecting sleeve, a fixing sleeve, an amplitude transformer, a longitudinal ultrasonic transducer and a middle cylindrical structure which are positioned in the mounting sleeve, a non-contact electric energy transmission system positioned outside the mounting sleeve, an ultrasonic power supply and signal processing equipment. The middle cylindrical structure and the amplitude transformer are sequentially connected below the longitudinal ultrasonic transducer by a flange structure, and the upper end of the longitudinal ultrasonic transducer is not contacted with other mechanisms; a flange mounting plate is arranged on the circumferential surface of the cylinder, and the flange mounting plate and the bottom of the mounting sleeve are fastened by bolts to form a flange structure II; according to the traditional ultrasonic vibration processing device, the middle cylindrical structure with two piezoelectric materials (upper and lower circular surfaces) is designed, so that the device has the function of accurately measuring the axial force under the ultrasonic auxiliary vibration processing condition under the condition that the original device is not influenced.

Description

A Drilling Device for Measuring Axial Force of Drill Bit Under Ultrasonic Auxiliary Vibration Condition

technical field

The invention belongs to the technical field of drilling and relates to a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic auxiliary vibration.

Background technique

Ultrasonic vibration assisted drilling is an emerging special processing technology that combines traditional drilling rotary processing technology with axial ultrasonic vibration technology. It makes the cutting amount change periodically, fundamentally changes the drilling mechanism, and makes the drill bit capable of pulsed intermittent cutting. This kind of processing technology can significantly reduce cutting force, improve processing efficiency, reduce surface roughness and improve tool life, and has processing advantages that cannot be compared with traditional drilling and rotating processing technology.

The axial force on the drill bit is an important processing parameter in the drilling process. Unreasonable axial force may lead to cracking of the workpiece material, breakage of the drill bit, and failure of the tool wear. The research on the axial force of drilling, especially It is very important to analyze the process of ultrasonic vibration assisted drilling under the condition of ultrasonic vibration.

In Document 1 (Structure Optimization Design and Experimental Research of Piezoelectric Grinding Dynamometer [D]. Harbin Engineering University, 2008), it is disclosed that the piezoelectric effect can be divided into positive piezoelectric effect and inverse piezoelectric effect. Positive piezoelectric effect means that when the crystal is subjected to an external force in a fixed direction, electric polarization will occur inside and at the same time, charges with opposite signs will be generated on two surfaces. The amount of charge generated by the crystal force is proportional to the magnitude of the external force. . Piezoelectric dynamometers are mostly based on the positive piezoelectric effect. The inverse piezoelectric effect refers to the phenomenon that the crystal is mechanically deformed by applying an alternating electric field to the crystal. Ultrasonic transducers are mostly based on the inverse piezoelectric effect.

In the traditional machining process, the piezoelectric dynamometer based on the piezoelectric effect is an important technology, which can accurately measure the axial force on the tool, but in the ultrasonic vibration-assisted machining, the existence of ultrasonic waves will also cause the piezoelectric effect of the piezoelectric material; as described in Document 2 (PVDF piezoelectric film calibration and application for ultrasonic vibration-assisted cutting force measurement [D]. Tianjin University, 2019.), the piezoelectric film is pasted on the variable On the surface of the rod, use the electrical signal generated by the deformation of the film to measure the axial force, or document 3 (Research on the key technology of ultrasonic machining piezoelectric three-way force measuring instrument [D]. Hangzhou Dianzi University, 2018.) The piezoelectric force measuring instrument made of piezoelectric material is placed at the bottom of the tool, and the axial force on the tool is used to reflect the axial force on the drill bit. Due to the influence of the piezoelectric effect, force measurement cannot be guaranteed under the condition of ultrasonic vibration. Accuracy, which seriously affects the force measurement accuracy of the force measurement device.

Therefore, it is of great significance to design a drilling device that can improve the measurement accuracy of the axial force of the drill bit under the condition of ultrasonic assisted vibration.

Contents of the invention

In order to overcome the shortcomings of the existing technical solutions, the present invention provides a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic auxiliary vibration.

In order to achieve the above object, the scheme adopted by the present invention is as follows:

A drilling device for measuring the axial force of a drill bit under ultrasonic-assisted vibration conditions, including a machine tool spindle, a machine tool spindle shell, a mounting sleeve and a horn, and also includes a longitudinal ultrasonic transducer located in the mounting sleeve and a mounting Non-contact power transmission system outside the sleeve, connecting sleeve, fixing sleeve, ultrasonic power supply and signal processing equipment;

The lower part of the longitudinal ultrasonic transducer is connected to the middle cylindrical structure and the horn with a flange structure in turn; the upper end of the longitudinal ultrasonic transducer is not in contact with other mechanisms; the flange structure is convenient for installing wires and piezoelectric materials, and can withstand the drill bit during processing. transmitted axial force.

The main body of the intermediate cylindrical structure is a cylindrical structure, the upper end surface of the cylinder is provided with a groove A with an opening upward, and the lower end surface of the cylinder is provided with a groove B with an opening downward. The shape and size of groove A and groove B are the same, and The line connecting the points at the same position on the two grooves is parallel to the central axis of the cylinder (such as the cross section of groove A is a square of 1mm×1mm, and the depth of groove A is 0.5mm, then the connecting line can be two concave The connection line between the center points of the bottom surface of the groove, preferably the connection line coincides with the central axis of the cylinder, that is, to ensure the accuracy of force measurement, the piezoelectric materials at the upper and lower places need to be located on the same straight line parallel to the central axis) ; A piezoelectric assembly with the same shape and size as the corresponding groove is placed in both groove A and groove B; the piezoelectric assembly is composed of nylon gaskets, piezoelectric materials (using PVDF film) and nylon gaskets stacked in sequence , the nylon gasket and the piezoelectric material are sheet-like structures, and the projected area of the two along the thickness direction is the same as the cross-sectional area of the groove A. If the groove is a rectangular groove with a certain depth, the length and width of the piezoelectric component The height is consistent with the length, width and depth of the groove, ensuring that the piezoelectric component and the groove are in a state of natural contact without additional force; the flange mounting plate c is placed on the circumferential surface of the cylinder, and the upper flange mounting plate c The surface is not higher than the bottom of the groove A, and the lower surface of the flange mounting plate c is not lower than the bottom of the groove B; the flange mounting plate c and the bottom of the mounting sleeve are fastened with bolts to form a flange structure II;

The non-contact power transmission system includes three primary side structures (each primary side structure is composed of a primary side magnetic core and a primary side coil) and three secondary side structures (each secondary side structure is composed of a secondary side magnetic core and a secondary side coil Composition); 1 primary structure and 1 secondary structure are recorded as a group, and the primary structure and secondary structure in the same group are on the same horizontal plane with an air gap between them; among them, a group of primary structures The primary side structure and the secondary side structure are respectively connected to the longitudinal ultrasonic power supply and the longitudinal ultrasonic transducer by wires, and the other two groups of primary side structures and secondary side structures are respectively connected to the signal processing equipment and the two piezoelectric components by wires;

The connecting sleeve is set on the outside of the installation sleeve and fastened on the installation sleeve with bolts;

The fixed sleeve is set on the outside of the connecting sleeve and fastened to the machine tool spindle shell with bolts;

The contactless power transmission system is installed on the connecting sleeve and the fixing sleeve.

Because the ultrasonic waves received by piezoelectric materials on the same horizontal plane may have deviations, which will affect the time domain difference method, and if multiple piezoelectric materials are installed, multiple symmetrical grooves must be opened on the end face of the middle cylindrical structure. If it cannot be guaranteed If it is strictly symmetrical, there may be differences in the received ultrasonic waves, resulting in unnecessary errors. Therefore, only one piezoelectric material is placed at each place, and the present invention uses a longitudinal ultrasonic transducer, and ultrasonic waves propagate along the axial direction, and the piezoelectric effect determines that the piezoelectric material in the present invention can only receive ultrasonic waves in the vertical direction of ultrasonic propagation. Ultrasonic signals, therefore, the piezoelectric material is placed at the upper and lower circular surfaces of the middle cylindrical structure.

As a preferred technical solution:

As mentioned above, a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic auxiliary vibration, the horn is composed of a circular flange mounting plate a, a transition cylinder, a horn cone and a tool head in sequence from top to bottom It is an integral molding, and the central axes of the four are on the same straight line. The outer contour of the luffing cone is a frustum-shaped structure with the large end on the top and the small end on the bottom; the outer diameter of the flange mounting plate a is larger than the outer diameter of the transition cylinder, and the outer diameter of the transition cylinder is the same as the outer diameter of the large end of the luffing cone. The outer diameter of the small end of the luffing cone is the same as that of the tool head.

As mentioned above, a drilling device for measuring the axial force of the drill bit under the condition of ultrasonic assisted vibration, the circumferential surface of the intermediate cylindrical structure (4) is located at the upper end surface and at the lower end surface, respectively, with two flange mounting plates, Denote as flange mounting plate b and flange mounting plate d; flange mounting plate a and flange mounting plate b are attached and fastened with bolts to form flange structure I.

As mentioned above, a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic auxiliary vibration, the longitudinal ultrasonic transducer includes load-bearing bolts (bolt steel material), front cover plate (YL12 material), several layers of piezoelectric ceramics (such as 4 layers, PZT8 material), several electrode sheets (made of beryllium bronze, the number of electrode sheets = the number of piezoelectric ceramics + 1), the rear cover (45 steel material) and insulating sleeve; Compress the front cover, piezoelectric ceramics and rear cover sequentially from top to bottom; the load-bearing bolts and piezoelectric ceramics are separated by insulating sleeves; piezoelectric ceramics and electrode sheets are placed alternately; the lower end of the rear cover is a flange mounting plate e; Flange mounting plate d is attached to flange mounting plate e and fastened with bolts to form flange structure III.

As mentioned above, a drilling device for measuring the axial force of the drill bit under the condition of ultrasonic assisted vibration, the non-contact power transmission system installed on the connecting sleeve and the fixed sleeve refers to:

The connecting sleeve is provided with three wire holes o1 and three outer annular grooves, and the wire holes o1 correspond to and communicate with the outer annular grooves one by one; the outer annular groove is formed on the outer surface of the connecting sleeve, and the wire hole o1 runs through the connecting sleeve. The side wall is formed, and the secondary side structure is placed in the outer annular groove;

The fixed sleeve includes three wire holes o2 and three inner annular grooves, the wire holes o2 correspond to and communicate with the inner annular grooves one by one, the inner annular groove is formed on the inner surface of the fixed sleeve, and the wire hole o2 runs through the fixed sleeve The side wall is formed, and the original edge structure is placed in the inner annular groove.

As mentioned above, a drilling device for measuring the axial force of the drill bit under the condition of ultrasonic assisted vibration, the secondary side structure is connected to the longitudinal ultrasonic transducer with a wire, which means that the piezoelectric ceramic is connected to the secondary side structure through the electrode sheet and the wire x , the wire x passes through the wire hole o1 corresponding to the outer annular groove where the secondary side structure is placed.

As mentioned above, a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic assisted vibration, the secondary side structure uses a wire to connect two piezoelectric components means:

On the end face of the cylinder where groove A and groove B are located, respectively set grooves for placing wires (no shape and depth requirements, just place wires);

The piezoelectric component in the groove A is connected to the secondary side structure through the wire y, and the wire y passes through the groove on the groove A and the wire hole o1 corresponding to the outer annular groove where the secondary side structure is placed;

The piezoelectric component in the groove B is connected to the secondary structure through the wire z, and the wire z passes through the groove on the groove B and the wire hole o1 corresponding to the outer annular groove where the secondary structure is placed.

As mentioned above, a drilling device for measuring the axial force of the drill bit under the condition of ultrasonic auxiliary vibration, in order to protect the wire so that it is not exposed in the processing environment, the flange structure connecting the intermediate cylindrical structure and the horn is connected with a Conduit, the conduit passes through the installation sleeve and connects with the connection sleeve, and the wire z passes through the groove on the groove B, and the conduit is connected to the wire hole o1 corresponding to the outer annular groove where the secondary side structure is placed.

According to the above-mentioned drilling device for measuring the axial force of the drill bit under the condition of ultrasonic assisted vibration, the distance between the upper end surface and the lower end surface of the middle cylindrical structure is 40mm-50mm. The distance between the upper end surface and the lower end surface ensures that the middle cylindrical structure in the structure has sufficient thickness so as not to be crushed by the axial force when the drill bit is processed, and the propagation speed of ultrasonic waves in solids is between 2km/s and 6km /s, and the height unit of the designed middle cylindrical structure is mm, the propagation of the ultrasonic wave between the two piezoelectric materials has almost no loss, so it can be guaranteed that under the sole action of the ultrasonic wave, the height of the middle cylindrical structure above and below The electrical signal is consistent.

As mentioned above, a drilling device for measuring the axial force of a drill bit under the condition of ultrasonic assisted vibration, in order to ensure that the normal processing is not affected, the projection surface of the piezoelectric material along the thickness direction is a square, and the area does not exceed the longitudinal ultrasonic transducer The projected surface area of the medium piezoelectric ceramic along the thickness direction, the thickness of the piezoelectric material does not exceed the thickness of a layer of piezoelectric ceramics, so as to prevent excessive absorption of ultrasonic vibration and poor drilling effect.

Principle of the present invention is:

The invention integrates the forward and reverse piezoelectric effects, eliminates the interference of the ultrasonic waves while generating the ultrasonic waves, and accurately measures the axial force. Specifically, by changing the structure of the existing ultrasonic drilling processing device, the present invention installs piezoelectric sensing elements capable of measuring ultrasonic waves and axial forces in both the stressed area and the non-stressed area, so as to ensure that the two places can receive the same In the case of ultrasonic waves, the time-domain difference method is used to remove the interference of ultrasonic waves, so as to obtain accurate axial force signals on the piezoelectric sensing element in the force-bearing area.

Beneficial effect

(1) According to the traditional ultrasonic vibration processing device, the present invention designs an intermediate cylindrical structure with two piezoelectric materials (upper and lower circular surfaces), so that the device can be used in ultrasonic-assisted vibration processing without affecting the work of the original device. The function of accurately measuring the axial force under certain conditions;

(2) The electrical signals obtained from the upper and lower piezoelectric materials of the middle cylindrical structure can be processed by signal processing equipment to remove the interference of ultrasonic waves, so as to obtain the axial force on the drill bit more accurately;

(3) The shape of the upper and lower piezoelectric materials in the middle cylindrical structure is specially designed, which can improve the measurement accuracy during measurement and reduce the absorption effect of the measurement part on the ultrasonic waves generated by the longitudinal ultrasonic transducer.

Description of drawings

Fig. 1 is the overall structural representation of drilling device of the present invention;

Fig. 2 is a cross-sectional view of the longitudinal ultrasonic transducer, the middle cylindrical structure and the horn;

3 is a schematic structural diagram of a non-contact power transmission system;

Fig. 4 is a schematic diagram of the propagation direction of ultrasonic waves and axial force;

Among them, 1-longitudinal ultrasonic transducer, 2-installation sleeve, 3-connecting sleeve, 4-middle cylindrical structure, 5-horn, 6-non-contact power transmission system, 7-ultrasonic power supply, 8- Signal processing equipment, 9-bearing bolts, 10-piezoelectric ceramics, 11-electrode sheet, 12-flange structure III, 13-flange structure II, 14-flange structure I, 15-transition cylinder, 16-transformer Width cone, 17-tool head, 18-front cover, 19-insulating sleeve, 20-back cover, 21-piezoelectric material, 22-nylon gasket, 23-machine spindle, 24-fixing sleeve, 25 -wire x, 26-wire y, 27-wire z, 28-primary core, 29-primary coil, 30-secondary core, 31-secondary coil, 32-air gap, 33-conduit, 34 - Machine tool spindle housings.

detailed description

The present invention will be further described below in combination with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

A drilling device for measuring the axial force of a drill bit under ultrasonic-assisted vibration conditions, as shown in Figure 1, comprising a machine tool spindle 23, a machine tool spindle shell 34, an installation sleeve 2, a connecting sleeve 3, a fixed sleeve 24, a variable Rod 5, longitudinal ultrasonic transducer 1 and intermediate cylindrical structure 4 located inside the installation sleeve 2, non-contact power transmission system 6 located outside the installation sleeve 2, ultrasonic power supply 7 and signal processing equipment 8;

The lower part of the longitudinal ultrasonic transducer 1 is sequentially connected with the intermediate cylindrical structure 4 and the horn 5 with a flange structure, and the upper end of the longitudinal ultrasonic transducer 1 is not in contact with other mechanisms;

The longitudinal ultrasonic transducer 1, as shown in Figure 2, includes load-bearing bolts 9 (bolt steel material), front cover plate 18 (YL12 material), 4 layers of piezoelectric ceramics 10 (PZT8 material), 5 electrode pieces 11 ( beryllium bronze), rear cover 20 (No. 45 steel) and insulating sleeve 19; load-bearing bolts 9 press the front cover 18, piezoelectric ceramics 10 and rear cover 20 sequentially from top to bottom; load-bearing bolts 9 and the piezoelectric ceramic 10 are separated by an insulating sleeve 19; the piezoelectric ceramic 10 and the electrode sheet 11 are alternately placed; the lower end of the rear cover 20 is a flange mounting plate e;

The middle cylindrical structure 4, as shown in Figure 2, its main body is a cylindrical structure, the distance between the upper end surface and the lower end surface of the middle cylindrical structure is 40mm-50mm; the upper end surface of the cylinder is provided with an upward groove A, and the cylindrical The lower end surface of the body is provided with a groove B with an opening downward. The cross-sections of groove A and groove B are both 1mm×1mm square, and the depth is 0.5mm. The line coincides with the central axis of the cylinder; a group of piezoelectric components with the same shape and size as the corresponding grooves are placed in groove A and groove B, and the piezoelectric components are composed of nylon gaskets 22, piezoelectric Material 21 (using PVDF film) and nylon gasket; nylon gasket 22 and piezoelectric material 21 are sheet-like structures, and the projected area of the two along the thickness direction is the same as the cross-sectional area of groove A, and the piezoelectric component The length, width, and height are consistent with the length, width, and depth of the groove (and the thickness of the piezoelectric material in it does not exceed the thickness of a layer of piezoelectric ceramics), ensuring that the piezoelectric component and the groove maintain natural contact without additional force state; two flange mounting plates are respectively arranged at the upper end surface and the lower end surface of the middle cylindrical structure 4, which are recorded as flange mounting plate b and flange mounting plate d;

Horn 5, as shown in Figure 2, is an integral molding composed of circular flange mounting plate a, transition cylinder 15, horn cone 16 and tool head 17 from top to bottom, and the central axis of the four Located on the same straight line; the outer contour of the luffing cone 16 is a frustum-shaped structure with the large end on the top and the small end on the bottom; the outer diameter of the flange mounting plate a is greater than the outer diameter of the transition cylinder 15, and the outer diameter of the transition cylinder 15 is the same as that of the variable The outer diameter of the large end of the wide cone 16 is the same, and the outer diameter of the small end of the luffing cone 16 is the same as that of the tool head 17;

The lower part of the longitudinal ultrasonic transducer 1 is sequentially connected with the intermediate cylindrical structure 4 and the horn 5 by a flange structure, which refers to: the flange mounting plate d is attached to the flange mounting plate e and fastened with bolts to form a flange structure III 12, and the flange The mounting plate a is attached to the flange mounting plate b and fastened with bolts to form the flange structure I14;

The connection sleeve 3 is set on the outside of the installation sleeve 2 and fastened on the installation sleeve 2 with bolts; the fixed sleeve 24 is set on the outside of the connection sleeve 3 and fastened on the machine tool spindle shell 34 with bolts; non-contact power transmission System 6 is installed on the connecting sleeve 3 and the fixed sleeve 24; as shown in Figure 1, a flange mounting plate c is arranged on the circumferential surface of the cylinder, and the upper surface of the flange mounting plate c is not higher than the bottom of the groove A , the lower surface of the flange mounting plate c is not lower than the bottom of the groove B; the flange mounting plate c and the bottom of the mounting sleeve 2 are fastened with bolts to form a flange structure II 13;

The non-contact power transmission system 6, as shown in Figure 3, comprises three primary side structures (each primary side structure is made up of primary side magnetic core 28 and primary side coil 29) and three secondary side structures (each secondary side structure The structure is composed of a secondary side magnetic core 30 and a secondary side coil 31); a primary side structure and a secondary side structure are recorded as a group, and the primary side structure and the secondary side structure in the same group are on the same horizontal plane and between the two There is an air gap 32 between them; wherein, one group of primary side structures and secondary side structures are respectively connected to the longitudinal ultrasonic power supply 7 and the longitudinal ultrasonic transducer 1 with wires, and the other two groups of primary side structures and secondary side structures are respectively connected to signal processing equipment with wires 8 and two piezoelectric components; the non-contact power transmission system 6 is installed on the connecting sleeve 3 and the fixed sleeve 24. Specifically, it means that the connecting sleeve 3 is provided with three wire holes o1 and three outer annular grooves, and the wire hole o1 and the The outer annular grooves are one-to-one corresponding and connected. The outer annular grooves are formed on the outer surface of the connecting sleeve 3. The wire hole o1 is formed through the side wall of the connecting sleeve 3. The secondary side structure is placed in the outer annular groove; the fixing sleeve 24 Including three wire holes o2 and three inner annular grooves, the wire holes o2 correspond to and communicate with the inner annular grooves one by one, the inner annular groove is formed on the inner surface of the fixed sleeve 24, and the wire hole o2 runs through the fixed sleeve 24 The side wall is formed, and the primary side structure is placed in the inner annular groove; the secondary side structure is connected with a wire. The longitudinal ultrasonic transducer 1 means: the piezoelectric ceramic 10 is connected to the secondary side structure through the electrode sheet 11 and the wire x25, and the wire x25 passes through Place the wire hole o1 corresponding to the outer annular groove of the secondary side structure; connecting the two piezoelectric components with wires in the secondary side structure refers to: setting grooves for placing wires on the end faces of the cylinder where the groove A and the groove B are located , the piezoelectric component in the groove A is connected to the secondary structure through the wire y26, the wire y26 passes through the groove on the groove A and the wire hole o1 corresponding to the outer annular groove where the secondary structure is placed, and the pressure in the groove B The electrical component is connected to the secondary side structure through the wire z27. In order to protect the wire z27 so that it is not exposed to the processing environment, the flange structure (that is, the flange structure I14) connecting the middle cylindrical structure 4 and the horn 5 is connected with a conduit 33 , the conduit 33 is connected to the connecting sleeve 3 through the installation sleeve 2, and the wire z27 passes through the groove on the groove B, and the conduit 33 is connected to the wire hole o1 corresponding to the outer annular groove where the secondary structure is placed.

A drilling device for measuring the axial force of a drill bit under the condition of ultrasonic assisted vibration, the measurement process is as follows:

As shown in Figure 4, when the drill bit is working, the machine tool spindle 23 drives the longitudinal ultrasonic transducer 1, the middle cylindrical structure 4, the horn 5, the tool head 17, the mounting sleeve 2 and the connecting sleeve 3 to rotate together, The fixed sleeve 24 is connected to the machine tool main shaft shell 34 by bolts, and remains stationary; the four-layer piezoelectric ceramic 10 generates longitudinal ultrasonic waves after receiving the electrical signal sent by the ultrasonic power supply 7, and passes through the lower end of the longitudinal ultrasonic transducer 1, After the middle cylindrical structure 4, two piezoelectric materials 21, and the horn 5, it is transmitted to the drill bit; the axial force sequentially passes through the tool head 17, the horn 5, the lower end of the middle cylindrical structure 4, the flange structure 13, and finally passes through the The installation sleeve 2 is transmitted to the machine tool spindle 23; the longitudinal ultrasonic transducer 1, the middle cylindrical structure 4 and the horn 5 can be regarded as a whole in the force analysis, because the middle flange structure II13 of the middle cylindrical structure 4 and the installation sleeve The cylinder 2 is connected, and the upper end of the longitudinal ultrasonic transducer 1 is not in contact with other mechanisms. During processing, the lower part of the flange structure II13 bears the axial force, and the upper end of the middle cylindrical structure 4 and the longitudinal ultrasonic transducer 1 are not affected by the axial force. effect;

When the drill bit is working, the piezoelectric material above the middle cylindrical structure 4 is only subjected to ultrasonic waves, and will not be subjected to the axial force generated during processing; while the piezoelectric material below the middle cylindrical structure 4 is simultaneously subjected to ultrasonic waves and axial forces. The effect of force; according to the electrical signals generated at the top and bottom of the middle cylindrical structure 4, signal processing equipment 8 is used to use time domain difference (Wei Xinhua, Zhang Jinmin, Dan Zhimin, Liu Chengliang. Impulse grain flow sensor to measure production signal Processing method [J]. Journal of Agricultural Engineering, 2014, 30 (15): 222-228.) to eliminate the same interference received by the two signals, so as to remove the interference of the ultrasonic signal;

According to the principle of piezoelectric force measurement, when the stress acting on the piezoelectric material changes, that is, the axial force on the drill bit changes, due to the positive piezoelectric effect, the piezoelectric material will generate a charge q=dσ, where σ is the pressure The stress on the electrical material in the z-axis direction, that is, the direction in which the drill bit is fed, d is the piezoelectric coefficient in all directions, and the generated charge q corresponds to the axial force one by one. By mathematically processing the restored electrical signal, The axial force on the drill bit can be obtained.

Claims (2)

1. The utility model provides a measure drilling device of drill bit axial force under ultrasonic wave auxiliary vibration condition, includes lathe main shaft (23), lathe main shaft shell (34), installation sleeve (2) and becomes width of cloth pole (5), characterized by: the device also comprises a longitudinal ultrasonic transducer (1) positioned in the mounting sleeve (2), a non-contact electric energy transmission system (6) positioned outside the mounting sleeve (2), a connecting sleeve (3), a fixing sleeve (24), an ultrasonic power supply (7) and signal processing equipment (8);

a flange structure is sequentially used below the longitudinal ultrasonic transducer (1) to connect the middle cylindrical structure (4) and the amplitude transformer (5); the upper end of the longitudinal ultrasonic transducer (1) is not contacted with other mechanisms;

the main body of the middle cylindrical structure (4) is in a cylindrical structure, the upper end surface of the cylinder is provided with a groove A with an upward opening, the lower end surface of the cylinder is provided with a groove B with a downward opening, the shapes and the sizes of the groove A and the groove B are the same, and the connecting line of points at the same positions on the two grooves is parallel to the central axis of the cylinder; piezoelectric components with the same shape and size as the corresponding grooves are arranged in the grooves A and the grooves B; the piezoelectric assembly consists of a nylon gasket (22), a piezoelectric material (21) and the nylon gasket (22) which are sequentially stacked, wherein the nylon gasket (22) and the piezoelectric material (21) are both of sheet structures; a flange mounting plate c is arranged on the circumferential surface of the cylinder, the upper surface of the flange mounting plate c is not higher than the bottom of the groove A, and the lower surface of the flange mounting plate c is not lower than the bottom of the groove B; the flange mounting plate c and the bottom of the mounting sleeve (2) are fastened by bolts to form a flange structure II (13);

the non-contact electric energy transmission system (6) comprises three primary side structures and three secondary side structures; the 1 primary side structure and the 1 secondary side structure are recorded as a group, the primary side structure and the secondary side structure which are positioned in the same group are positioned on the same horizontal plane, and an air gap (32) is formed between the primary side structure and the secondary side structure; one group of primary structures and one group of secondary structures are respectively connected with an ultrasonic power supply (7) and a longitudinal ultrasonic transducer (1) by leads, and the other two groups of primary structures and the other two groups of secondary structures are respectively connected with a signal processing device (8) and two piezoelectric components by leads;

the connecting sleeve (3) is sleeved outside the mounting sleeve (2) and fastened on the mounting sleeve (2) by bolts;

the fixed sleeve (24) is sleeved outside the connecting sleeve (3) and is fastened on a machine tool spindle shell (34) by bolts;

the non-contact electric energy transmission system (6) is arranged on the connecting sleeve (3) and the fixed sleeve (24);

the amplitude transformer (5) is an integrally formed part which consists of a circular flange mounting plate a, a transition cylinder (15), an amplitude-variable cone (16) and a tool head (17) from top to bottom in sequence, and the central shafts of the amplitude transformer and the tool head are positioned on the same straight line;

2 flange mounting plates are respectively arranged on the circumferential surface of the middle cylindrical structure (4) at the upper end surface and the lower end surface and are marked as a flange mounting plate b and a flange mounting plate d; the flange mounting plate a and the flange mounting plate b are attached and fastened by bolts to form a flange structure I (14);

the longitudinal ultrasonic transducer (1) comprises a bearing bolt (9), a front cover plate (18), a plurality of layers of piezoelectric ceramics (10), a plurality of electrode plates (11), a rear cover plate (20) and an insulating sleeve (19); the force bearing bolt (9) sequentially compresses the front cover plate (18), the piezoelectric ceramic (10) and the rear cover plate (20) from top to bottom; the bearing bolt (9) is separated from the piezoelectric ceramic (10) by an insulating sleeve (19); the piezoelectric ceramics (10) and the electrode plates (11) are alternately arranged; the lower end of the rear cover plate (20) is provided with a flange mounting plate e; the flange mounting plate d and the flange mounting plate e are attached and fastened by bolts to form a flange structure III (12);

the projection surface of the piezoelectric material (21) along the thickness direction is square, the area of the projection surface of the piezoelectric ceramic (10) in the longitudinal ultrasonic transducer (1) along the thickness direction is not more than the area of the projection surface, and the thickness of the piezoelectric material (21) is not more than the thickness of one layer of piezoelectric ceramic;

the non-contact type electric energy transmission system (6) is arranged on the connecting sleeve (3) and the fixed sleeve (24) and comprises the following components in percentage by weight:

the connecting sleeve (3) is provided with three wire holes o1 and three outer annular grooves, and the wire holes o1 are in one-to-one correspondence and communication with the outer annular grooves; an outer annular groove is formed on the outer surface of the connecting sleeve (3), a wire guide hole o1 is formed by penetrating through the side wall of the connecting sleeve (3), and a secondary edge structure is arranged in the outer annular groove;

the fixing sleeve (24) comprises three wire holes o2 and three inner annular grooves, the wire holes o2 correspond to and are communicated with the inner annular grooves one by one, the inner annular grooves are formed on the inner surface of the fixing sleeve (24), the wire holes o2 are formed by penetrating through the side wall of the fixing sleeve (24), and original edge structures are placed in the inner annular grooves;

the secondary side structure is connected with the longitudinal ultrasonic transducer (1) by a lead, and the method comprises the following steps: the piezoelectric ceramic (10) is connected with the secondary side structure through an electrode plate (11) and a lead x (25), and the lead x (25) penetrates through a lead hole o1 corresponding to an outer annular groove for placing the secondary side structure;

the secondary side structure is connected with the two piezoelectric components by a lead, and the secondary side structure is characterized in that:

grooves for placing wires are respectively arranged on the end surfaces of the cylinders where the grooves A and the grooves B are arranged;

the piezoelectric assembly in the groove A is connected with the secondary side structure through a lead y (26), and the lead y (26) penetrates through a groove on the groove A and a lead hole o1 corresponding to an outer annular groove for placing the secondary side structure;

the piezoelectric assembly in the groove B is connected with the secondary side structure through a lead z (27), and the lead z (27) passes through the groove on the groove B and a lead hole o1 corresponding to an outer annular groove for placing the secondary side structure.

2. A drilling assembly for measuring the axial force of a drill bit under ultrasonic-assisted vibration conditions as defined in claim 1 wherein the flange structure of the intermediate cylindrical structure (4) to the horn (5) is connected to a conduit (33), the conduit (33) is connected to the connecting sleeve (3) through the mounting sleeve (2), and the wire z (27) is connected to the wire guide (33) through the groove in the recess B and the wire guide opening o1 corresponding to the outer annular groove in which the secondary structure is located.

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