A four-component strain-type milling force measuring machine tool cutting tool system

Abstract

This invention relates to the field of intelligent manufacturing technology and discloses a four-component strain gauge milling force measuring machine tool system. The system includes a tool holder, an upper connecting flange, a strain gauge elastomer, a lower connecting flange, and a tool base, all coaxially assembled in sequence. The tool base holds the tool. A loading platform is located at the center of the crossbeam of the strain gauge elastomer. The crossbeam is connected to a double-layered cross-floating beam assembly, with an outer connecting platform connecting adjacent double-layered cross-floating beam assemblies. Thin-film strain gauges forming Wheatstone bridges are adhered to the surfaces of the crossbeam and the double-layered cross-floating beam assemblies. A PCB board carrying a data acquisition and wireless transmission system is installed inside a stepped housing fitted outside the tool holder. The PCB board is electrically connected to the thin-film strain gauges. This invention achieves independent detection and dynamic calculation of four-component milling forces, with low inter-dimensional coupling, a compact structure, high measurement accuracy, and wide applicability.

Description

Technical Field

[0001] This invention belongs to the field of intelligent manufacturing technology, and particularly relates to the field of online milling force measurement technology, specifically a four-component strain-type milling force measuring machine tool system. Background Technology

[0002] Milling force is one of the most fundamental signals reflecting information about the milling process and is also the most widely used signal for monitoring the milling process. It is closely related to tool parameters, milling conditions, tool status, and workpiece surface quality. Therefore, online measurement of milling force is of great significance for studying the milling process and guiding actual machining.

[0003] In existing technologies, strain gauge milling force measurement machine tool systems have advantages such as low cost, stable signal, and high reliability. However, existing strain gauge milling force measurement machine tool systems have some problems. These are mainly due to limitations in their strain elastomer structure design, resulting in a large overall tool holder size, making integration into compact machine tools difficult. Furthermore, they often employ a fixed design, making them incompatible with different tool holder interfaces. Therefore, they cannot be flexibly applied in actual machining processes, significantly limiting the applicability and ease of use of milling force measurement technology. Summary of the Invention

[0004] To address the limitations of existing online milling force measurement systems, such as the constraints of strain-elastic body structure design making integration into compact machine tools difficult and hindering flexible application in actual machining processes, thus significantly restricting the applicability and ease of use of milling force measurement technology, this invention provides a four-component strain-based milling force measurement machine tool system.

[0005] This invention is achieved using the following techniques:

[0006] This invention provides a four-component strain-type milling force measuring machine tool system, comprising a tool holder, an upper connecting flange, a strain elastomer, a lower connecting flange, and a tool base, which are coaxially assembled in sequence. The tool base holds the tool. The strain elastomer includes a crossbeam with a loading platform at its center. Each end of the crossbeam is vertically connected to a pair of double-layer cross-floating beams, and an outer ring connecting platform connects adjacent double-layer cross-floating beams. Thin-film strain gauges forming a Wheatstone bridge are attached to the surfaces of the crossbeam and the double-layer cross-floating beams. The upper end of the strain elastomer is connected to the tool holder via the upper connecting flange, and the lower end of the strain elastomer is connected to the tool base via the lower connecting flange. A stepped housing is fitted onto the lower part of the tool holder via an upper end cover, and a lower end cover is installed on the lower end face of the stepped housing. A PCB board carrying a data acquisition and wireless transmission system is installed inside the stepped housing. The PCB board is powered by a battery installed in a battery compartment, which is also installed inside the stepped housing. The PCB board is electrically connected to the thin-film strain gauges.

[0007] In practice, the device consists of a tool holder, an upper connecting flange, a strain elastic body, a lower connecting flange, and a tool base, which are coaxially assembled in sequence. The upper end of the strain elastic body is connected to the tool holder through the upper connecting flange, and the lower end of the strain elastic body is connected to the tool base through the lower connecting flange. The tool base holds the tool.

[0008] To ensure coaxial assembly, a first positioning hole is opened in the center of the lower end face of the tool holder, which mates with the upper flange boss on the upper end face of the upper connecting flange. That is, the first positioning hole on the lower end face of the tool holder is fitted with the upper flange boss of the upper connecting flange.

[0009] The lower end face of the upper connecting flange has a second positioning hole in the center that mates with the outer circumference of the outer ring connecting platform of the strain elastomer. That is, the outer edge of the curved surface of the outer ring connecting platform of the strain elastomer is a concentric arc surface, and the second positioning hole on the lower end face of the upper connecting flange mates with the outer edge of the curved surface of the outer ring connecting platform.

[0010] The lower connecting flange has an upper boss and a lower boss on its two ends respectively. The upper boss has a third positioning hole in the center that mates with the outer periphery of the loading platform. The tool base has a fourth positioning hole in the center of its upper end face that mates with the lower boss. That is, the upper boss of the lower connecting flange is positioned with the loading platform through the third positioning hole, while the lower boss of the lower connecting flange is engaged with the fourth positioning hole of the tool base.

[0011] Furthermore, the lower part of the tool holder has a first stepped through hole, and the tool holder is connected to the upper connecting flange by a bolt passing through the first stepped through hole.

[0012] The upper connecting flange has four second-step through holes corresponding to the positions of the first bolt holes on the four outer ring connecting platforms. The upper connecting flange is connected to the strain elastic body by bolts that pass through the second-step through holes and the first bolt holes in sequence.

[0013] The loading platform of the strain elastomer has a second threaded hole evenly distributed along the circumference. The lower connecting flange has a third stepped through hole corresponding to the position of the second threaded hole. The lower connecting flange is connected to the strain elastomer by bolts that pass through the third stepped through hole and the second threaded hole in sequence.

[0014] The upper annular protrusion of the tool base has through holes evenly distributed around its circumference, and the lower connecting flange has a third screw hole corresponding to the position of the through holes. The tool base is connected to the lower connecting flange by bolts that pass through the through holes and the third screw hole in sequence.

[0015] The strain-elastic body includes a crossbeam with a loading platform at its center. Each end of the crossbeam is vertically connected to a pair of double-layered intersecting floating beams. Adjacent double-layered intersecting floating beam groups are connected by an outer ring connecting platform. Each double-layered intersecting floating beam group includes two staggered front and rear double-layered floating beams. The loading surface of the front double-layered floating beam is connected to the crossbeam, and the fixing surface of the rear double-layered floating beam is connected to the outer ring connecting platform. This is to achieve the desired effect during milling. , , , The four-component milling force measurement involves attaching thin-film strain gauges, which are assembled into a Wheatstone bridge, to the surface of the crossbeam and the surface of the double-layer cross floating beam assembly. Both the front and rear double-layer floating beams consist of two parallel beams, with thin-film strain gauges attached to the outer surface of the beams. Specifically, thin-film strain gauges are attached to the outer surface of each front double-layer floating beam.

[0016] The crossbeam consists of four crossbeams arranged in a cross shape, namely the first crossbeam, the second crossbeam, the third crossbeam, and the fourth crossbeam. Only two of the crossbeams have thin-film strain gauges attached to their side surfaces. The two crossbeams with attached thin-film strain gauges are arranged radially symmetrically along the loading platform, that is, the first crossbeam and the third crossbeam have thin-film strain gauges attached to their side surfaces. The remaining two crossbeams do not have thin-film strain gauges attached to them, that is, the second crossbeam and the fourth crossbeam.

[0017] Thin-film strain gauges are attached to the upper and lower outer surfaces of the rear double-layer floating beam. The two sets of double-layer cross floating beams containing the rear double-layer floating beams with attached thin-film strain gauges are connected to the crossbeams without attached thin-film strain gauges. That is, the rear floating beams connected to the second and fourth crossbeams have thin-film strain gauges attached to their upper and lower outer surfaces.

[0018] Thin-film strain gauges are divided into four groups to detect surface strain caused by milling force, corresponding to... , , , The detection of four components of milling force is used to generate voltage changes to characterize the changes in milling force, thereby realizing the voltage signal output of the strain gauge.

[0019] The lower part of the tool holder is fitted with a stepped housing through an upper end cover. The stepped housing includes an upper housing and a lower housing fixed by a stepped annular surface. The upper end face of the upper housing is bolted to the outer ring of the upper end cover, and the inner ring of the upper end cover is bolted to the lower annular protrusion of the tool holder. A lower end cover is installed on the lower end face of the stepped housing. That is, the lower housing has an internal threaded post fixed on the stepped annular surface. The lower end cover is installed on the lower end face of the lower housing by bolts that mate with the internal threaded post.

[0020] The stepped housing houses a PCB board carrying a data acquisition and wireless transmission system. The PCB board has mounting holes evenly distributed on the stepped ring surface. The PCB board is fixedly connected to the stepped ring surface by bolts passing through the mounting holes. The PCB board is powered by a battery installed in the battery compartment. The battery compartment is installed in the stepped housing, that is, the battery compartments are symmetrically installed in the upper housing and are located above the PCB board. The PCB board is electrically connected to the thin film strain gauge.

[0021] Specifically, the PCB board includes a DC power output unit, an amplifier module, an AD conversion module, a main control module, and a wireless transmission module.

[0022] The PCB board's DC power output unit outputs 3.3V to power the thin-film strain gauges, which in turn power the four Wheatstone bridges. These strain gauges form four Wheatstone bridges connected to the input channels of their respective amplification modules. Each amplification module contains four independent amplification circuits, amplifying the millivolt-level voltage signals output by the Wheatstone bridges to a range of -5V to +5V for acquisition by the AD conversion module. The AD conversion module connects to the four amplification circuits to synchronously acquire the amplified voltage signals. The output of each amplification module is connected to the main control module via SPI communication through the AD conversion module. The main control module is connected to a PC via a wireless transmission module. In other words, the output of each amplification circuit is connected to the AD conversion module, which performs synchronous analog-to-digital conversion on the amplified voltage signals and connects to the main control module via SPI communication. The main control module is connected to a PC via a wireless transmission module, which sends the processed data from the main control unit to the external PC.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This application provides a four-component strain-type milling force measuring machine tool system, which adopts a double-layer cross-floating beam group and a cross beam composite strain elastic body structure. Through space optimization layout, the overall volume is greatly reduced, solving the problem of excessive size caused by structural redundancy in traditional force measuring instruments. It can be directly integrated into standard machine tool systems without modifying the machining environment.

[0025] This application utilizes a strain gauge elastomer in conjunction with modularly designed components to measure milling force in a tool system. The tool holder, upper connecting flange, strain gauge elastomer, lower connecting flange, and tool base are assembled in series using bolts with holes, ensuring high coaxiality, reducing reliance on installation precision, and improving system stability. The circuit system is connected to the tool holder to achieve milling force signal acquisition and wireless transmission. Furthermore, the outer ring connecting platform of the strain gauge elastomer, designed with bolts and threaded holes, ensures high coaxiality, reducing reliance on installation precision and improving system stability. By replacing different upper and lower connecting flanges, different types of tool holders and tool bases can be connected to adapt to different machining scenarios.

[0026] This application is based on four sets of Wheatstone full-bridge circuits composed of twenty thin-film strain gauges, combined with the mechanical decoupling design of double-layer cross floating beam group and cross beam, to realize independent detection and dynamic calculation of four components of milling force. It has low inter-dimensional coupling and compact structure, and solves the problems of low measurement accuracy and limited applicability of existing milling force measurement technology.

[0027] This application features a reasonable structure and ingenious design, effectively solving the problems of large size and limited applicability of existing strain gauge wireless rotary force measuring instruments. It is suitable for milling operations in various settings, such as laboratories and production sites. Attached Figure Description

[0028] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0029] Figure 2 This is an exploded view of the present invention.

[0030] Figure 3 This is a cross-sectional view of the present invention.

[0031] Figure 4 This is a schematic diagram of the structure of the knife handle 1 in this invention.

[0032] Figure 5 This is a half-sectional view of the knife handle 1 in this invention.

[0033] Figure 6 This is a top view of the knife handle 1 in this invention.

[0034] Figure 7 This is a half-sectional view of the upper connecting flange 7 in this invention.

[0035] Figure 8 This is a top view of the upper connecting flange 7 in this invention.

[0036] Figure 9 This is a three-dimensional structural schematic diagram of the strain elastomer 19 in this invention.

[0037] Figure 10 This is a schematic diagram of the structure of the double-layer cross-floating beam group 1906 in this invention.

[0038] Figure 11 This is a half-sectional view of the lower connecting flange 9 in this invention.

[0039] Figure 12 This is a top view of the lower connecting flange 9 in this invention.

[0040] Figure 13 This is a half-sectional view of the tool base 11 in this invention.

[0041] Figure 14 This is a top view of the tool base 11 in this invention.

[0042] Figure 15 This is a bottom view of the stepped housing 14 in this invention.

[0043] Figure 16 This is a structural block diagram of the data acquisition and wireless transmission system in this invention.

[0044] Figure 17 This is a diagram showing the arrangement of the thin-film strain gauge 8 in this invention.

[0045] Figure 18 This is a schematic diagram of the installation of the thin film strain gauge 8 on the strain elastomer 19 in this invention.

[0046] Figure 19 These are four Wheatstone bridges composed of strain gauges used in this invention to detect milling forces.

[0047] In the diagram: 1-Tool holder; 101-First positioning hole; 102-First stepped through hole; 103-Fifth screw hole; 2-First bolt; 3-Second bolt; 4-Upper end cap; 5-Third bolt; 6-Fourth bolt; 7-Upper connecting flange; 701-Upper flange boss; 702-Second positioning hole; 703-Second stepped through hole; 704-Fourth screw hole; 8-Third film strain gauge; 801-First thin film strain gauge; 802-Second thin film strain gauge; 803-Third thin film strain gauge; 804-Fourth thin film strain gauge 805-Fifth thin film strain gauge; 806-Sixth thin film strain gauge; 807-Seventh thin film strain gauge; 808-Eighth thin film strain gauge; 809-Ninth thin film strain gauge; 810-Tenth thin film strain gauge; 811-Eleventh thin film strain gauge; 812-Twelfth thin film strain gauge; 813-Thirteenth thin film strain gauge; 814-Fourteenth thin film strain gauge; 815-Fifteenth thin film strain gauge; 816-Sixteenth thin film strain gauge; 817-Seventeenth thin film strain gauge; 818-Eighteenth thin film strain gauge. Membrane strain gauge; 819 - Nineteenth thin film strain gauge; 820 - Twentieth thin film strain gauge; 9 - Lower connecting flange; 901 - Upper boss; 902 - Lower boss; 903 - Third screw hole; 904 - Third stepped through hole; 905 - Third positioning hole; 10 - Fifth bolt; 11 - Tool holder; 1101 - Fourth positioning hole; 1102 - Through hole; 12 - Sixth bolt; 13 - Tool; 14 - Stepped housing; 1401 - Battery compartment; 1402 - PCB board mounting hole; 1403 - Internal screw hole 1404 - Upper end cap connection hole; 1405 - Upper shell; 1406 - Lower shell; 1407 - Stepped annular surface; 15 - Battery; 16 - PCB board; 17 - Lower end cap; 18 - Seventh bolt; 19 - Strain elastic body; 1901 - Outer ring connecting platform; 1902 - Loading platform; 1903 - Cross beam; 1904 - First screw hole; 1905 - Second screw hole; 1906 - Double-layer cross floating beam assembly; 19061 - Front double-layer floating beam; 19062 - Rear double-layer floating beam. Detailed Implementation

[0048] The specific embodiments of the present invention will be described in detail below.

[0049] A four-component strain-based milling force measuring machine tool system, such as Figures 1-18 As shown, the tool holder 1, upper connecting flange 7, strain elastic body 19, lower connecting flange 9, and tool base 11 are coaxially assembled in sequence. The upper end of the strain elastic body 19 is connected to the tool holder 1 through the upper connecting flange 7, and the lower end of the strain elastic body 19 is connected to the tool base 11 through the lower connecting flange 9. The tool base 11 holds the tool 13.

[0050] To ensure coaxial assembly, a first positioning hole 101 is provided at the center of the lower end face of the tool holder 1, which mates with the upper flange boss 701 on the upper end face of the upper connecting flange 7. That is, the first positioning hole 101 on the lower end face of the tool holder 1 is fitted with the upper flange boss 701 on the upper connecting flange 7.

[0051] like Figure 7 As shown, a second positioning hole 702 is opened in the center of the lower end face of the upper connecting flange 7, which mates with the outer periphery of the outer ring connecting platform 1901 of the strain elastomer 19. That is, the outer edge of the curved surface of the outer ring connecting platform 1901 of the strain elastomer 19 is a concentric arc surface, and the second positioning hole 702 on the lower end face of the upper connecting flange 7 mates with the outer edge of the curved surface of the outer ring connecting platform 1901.

[0052] like Figure 11 , 12 As shown, the two end faces of the lower connecting flange 9 are respectively provided with an upper boss 901 and a lower boss 902. The upper boss 901 has a third positioning hole 905 in the center that mates with the outer periphery of the loading platform 1902. The upper end face of the tool base 11 has a fourth positioning hole 1101 in the center that mates with the lower boss 902. That is, the upper boss 901 of the lower connecting flange 9 is positioned with the loading platform 1902 through the third positioning hole 905, while the lower boss 902 of the lower connecting flange 9 is engaged with the fourth positioning hole 1101 of the tool base 11.

[0053] In this embodiment, the tool holder 1 is a BT40 tool holder, and a stepped housing 14 is fitted onto the lower part of the tool holder 1 through the upper end cover 4, such as... Figure 15 As shown, the stepped housing 14 includes an upper housing 1405 and a lower housing 1406 fixed by a stepped annular surface 1407. The upper end face of the upper housing 1405 has an upper end cover connecting hole 1404. The upper end cover 4 is installed on the upper end face of the upper housing 1405 by a second bolt 3 passing through the outer ring of the upper end cover 4 and the upper end cover connecting hole 1404. The lower annular protrusion of the tool handle 1 has six fifth screw holes 103 at the intervals of the first stepped through hole 102. The inner ring of the upper end cover 4 is connected to the lower annular protrusion of the tool handle 1 by a first bolt 2 passing through the inner ring of the upper end cover 4 and the fifth screw holes 103. The lower end cover 17 is installed on the lower end face of the stepped housing 14. That is, the lower housing 1406 has three internal threaded posts 1403 fixed on the stepped annular surface 1407. The lower end cover 17 is installed on the lower end face of the lower housing 1406 by a seventh bolt 18 that mates with the internal threaded posts 1403.

[0054] like Figures 4-6As shown in Figure 8, the lower part of the tool holder 1 is provided with a lower annular protrusion, and the lower annular protrusion has six first stepped through holes 102 along the axial direction. The six first stepped through holes 102 are evenly arranged in the circumferential direction. The upper connecting flange 7 has a fourth screw hole 704 at the corresponding position of the first stepped through holes 102. The tool holder 1 is connected to the upper connecting flange 7 by six third bolts 5 that pass through the first stepped through holes 102 and the fourth screw hole 704 in sequence.

[0055] like Figures 8-10 As shown, the outer ring connecting platform 1901 of the strain elastomer 19 is provided with a first screw hole 1904, and the upper connecting flange 7 is provided with a second stepped through hole 703 corresponding to the position of the four first screw holes 1904. The upper connecting flange 7 is connected to the strain elastomer 19 by a fourth bolt 6 that passes through the second stepped through hole 703 and the first screw hole 1904 in sequence.

[0056] The loading platform 1902 of the strain elastomer 19 has six second screw holes 1905 evenly opened along the circumference. The lower connecting flange 9 has six third stepped through holes 904 corresponding to the positions of the second screw holes 1905. The lower connecting flange 9 is connected to the strain elastomer 19 by fifth bolts 10 that pass through the third stepped through holes 904 and second screw holes 1905 in sequence.

[0057] like Figure 13 , 14 As shown, the upper part of the tool base 11 is provided with an upper annular protrusion, and four through holes 1102 are evenly distributed around the circumference of the upper annular protrusion. The lower connecting flange 9 is provided with four third screw holes 903 corresponding to the positions of the through holes 1102. The tool base 11 is connected to the lower connecting flange 9 by a sixth bolt 12 that passes through the through holes 1102 and the third screw holes 903 in sequence.

[0058] The strain elastic body 19 includes a crossbeam 1903, which includes four crossbeams arranged in a cross shape, namely a first crossbeam, a second crossbeam, a third crossbeam, and a fourth crossbeam. In this embodiment, the first crossbeam and the third crossbeam are in the Y direction, and the second crossbeam and the fourth crossbeam are in the X direction.

[0059] A loading platform 1902 is provided in the center of the crossbeam 1903. Each end of the crossbeam 1903 is vertically connected to a pair of double-layered cross-floating beam groups 1906. An outer ring connecting platform 1901 connects each adjacent pair of double-layered cross-floating beam groups 1906. Each double-layered cross-floating beam group 1906 includes two staggered front double-layered floating beams 19061 and a rear double-layered floating beam 19062. The loading surface of the front double-layered floating beam 19061 is connected to the crossbeam 1903, and the fixing surface of the rear double-layered floating beam 19062 is connected to the outer ring connecting platform 1901. This is to achieve the desired loading surface during milling. , , , The four-component milling force measurement is performed on the surface of the crossbeam 1903 and the surface of the double-layer cross floating beam assembly 1906, where thin film strain gauges 8 are attached to form a Wheatstone bridge. The front double-layer floating beam 19061 and the rear double-layer floating beam 19062 each include two parallel beams. Thin film strain gauges 8 are attached to the outer surface of the beams. The beams of the front double-layer floating beam 19061 are arranged longitudinally, while the beams of the rear double-layer floating beam 19062 are arranged transversely.

[0060] Specifically, a thin film strain gauge 8 is attached to the outer surface of each front-end double-layer floating beam 19061;

[0061] Thin film strain gauges 8 are attached to the side surfaces of the first and third crossbeams, while thin film strain gauges 8 are not attached to the second and fourth crossbeams.

[0062] Thin film strain gauges 8 are attached to the upper and lower outer surfaces of the rear double-layer floating beam 19062, which is connected to the second and fourth crossbeams via the front double-layer floating beam 19061.

[0063] In this embodiment, the double-layer cross floating beam group 1906 serves as a force measuring unit for milling forces in the X, Y, and Z directions. When the loading platform 1902 is subjected to X / Y direction forces, the front section of the double-layer floating beam 19061 in the X / Y direction undergoes strain; when the loading platform 1902 is subjected to Z direction forces, the rear section of the double-layer floating beam 19062 in the Z direction undergoes strain; the cross beam 1903 serves as a force measuring unit for Z-direction torque. When the loading platform 1902 is subjected to Z-direction torque, all four cross beams undergo strain.

[0064] The thin-film strain gauges are divided into four groups of eight to detect the surface strain caused by milling force, corresponding to... , , , The detection of four components of milling force is used to generate voltage changes to characterize the changes in milling force, thereby realizing the voltage signal output of the strain gauge.

[0065] like Figure 17 , 18 As shown, in this embodiment, the seventeenth thin-film strain gauge 817 and the eighteenth thin-film strain gauge 818 are attached to both sides of the first crossbeam, and the twentieth thin-film strain gauge 820 and the nineteenth thin-film strain gauge 819 are attached to both sides of the third crossbeam.

[0066] The outer sides of the two front-end double-layer floating beams 19061 connected to the end of the first crossbeam are respectively attached with the sixth thin film strain gauge 806 and the eighth thin film strain gauge 808. The outer sides of the two front-end double-layer floating beams 19061 connected to the end of the third crossbeam are respectively attached with the fifth thin film strain gauge 805 and the seventh thin film strain gauge 807.

[0067] The outer sides of the two front-end double-layer floating beams 19061 connected to the end of the second crossbeam are respectively attached with a first thin film strain gauge 801 and a third thin film strain gauge 803. The outer sides of the two front-end double-layer floating beams 19061 connected to the end of the fourth crossbeam are respectively attached with a second thin film strain gauge 802 and a fourth thin film strain gauge 804.

[0068] The upper side of the rear double-layer floating beam 19062 connected to the second crossbeam is respectively attached to the ninth thin-film strain gauge 809 and the eleventh thin-film strain gauge 811, and the lower side is respectively attached to the tenth thin-film strain gauge 810 and the twelfth thin-film strain gauge 812; the upper side of the rear double-layer floating beam 19062 connected to the fourth crossbeam is respectively attached to the thirteenth thin-film strain gauge 813 and the fifteenth thin-film strain gauge 815, and the lower side is respectively attached to the fourteenth thin-film strain gauge 814 and the sixteenth thin-film strain gauge 816.

[0069] When the loading platform 1902 is subjected to a positive X-force, the first thin-film strain gauge 801 and the third thin-film strain gauge 803 are compressed, while the second thin-film strain gauge 802 and the fourth thin-film strain gauge 804 are stretched; conversely, when the loading platform 1902 is subjected to a negative X-force, the first thin-film strain gauge 801 and the third thin-film strain gauge 803 are stretched, while the second thin-film strain gauge 802 and the fourth thin-film strain gauge 804 are compressed. The strains generated by the four thin-film strain gauges 8 are respectively denoted as... , , , .

[0070] When the loading platform 1902 is subjected to a positive Y-force, the fifth and seventh thin-film strain gauges 805 and 807 are compressed, while the sixth and eighth thin-film strain gauges 806 and 808 are stretched; conversely, when the loading platform 1902 is subjected to a negative Y-force, the fifth and seventh thin-film strain gauges 805 and 807 are stretched, while the sixth and eighth thin-film strain gauges 806 and 808 are compressed. The strains generated by the four thin-film strain gauges 8 are denoted as follows: , , , .

[0071] When the loading platform 1902 is subjected to a positive Z force, the tenth, twelfth, fourteenth, and sixteenth thin-film strain gauges 810, 812, 814, and 816 are compressed, while the ninth, eleventh, thirteenth, and fifteenth thin-film strain gauges 819 and 810 are stretched. Conversely, when the loading platform 1902 is subjected to a negative Z force, the tenth, twelfth, 812, fourteenth, and sixteenth thin-film strain gauges 814 and 816 are stretched, while the ninth, eleventh, thirteenth, and fifteenth thin-film strain gauges 819 and 810 are compressed. The strains generated by the eight thin-film strain gauges 8 are denoted as follows: , , , , , , , .

[0072] When the loading platform 1902 is subjected to a positive Z-direction torque, the eighteenth thin-film strain gauge 818 and the twentieth thin-film strain gauge 820 are compressed, while the seventeenth thin-film strain gauge 817 and the nineteenth thin-film strain gauge 819 are stretched; conversely, when the loading platform 1902 is subjected to a negative Z-direction torque, the eighteenth thin-film strain gauge 818 and the twentieth thin-film strain gauge 820 are stretched, while the seventeenth thin-film strain gauge 817 and the nineteenth thin-film strain gauge 819 are compressed. The strains generated by the four thin-film strain gauges 8 are denoted as follows: , , , .

[0073] like Figure 19 As shown, the strain values ​​measured by strain gauges at various locations on the strained elastic body. The strain values ​​output by the Wheatstone bridge under various external forces are related as follows:

[0074] & ε F x = ε 801 - ε 802 + ε 803 - ε 804 & ε F y = ε 805 - ε 806 + ε 807 - ε 808 & ε F z = 1 2 [( ε 809 + ε 811 )-( ε 810 + ε 812 )+( ε 813 + ε 815 )-( ε 814 + ε 816 )] & ε M z = ε 817 - ε 818 + ε 819 - ε 820 &&

[0075] Output voltage of the four Wheatstone bridges , , , Signal and strain value of elastic body , , , The following relationship exists:

[0076]

[0077] In the formula, denoted as the sensitivity coefficient of the strain gauge.

[0078] This is the input voltage of the Wheatstone bridge.

[0079] Four-component cutting force obtained from strained elastic body , , , The relationship between the voltage and the output voltage of the Wheatstone bridge can be determined by the following formula:

[0080]

[0081] In the formula, The tensile and compressive forces acting in the X direction.

[0082] The tensile and compressive forces acting in the Y direction.

[0083] The tensile and compressive forces acting in the Z direction.

[0084] This is the torque in the Z direction.

[0085] This is the calibration matrix obtained after calibrating the tool holder 1 using a force calibration device.

[0086] A PCB board 16 carrying a data acquisition and wireless transmission system is installed inside the stepped housing 14. PCB board mounting holes 1402 are evenly distributed on the stepped annular surface 1407. The PCB board 16 is fixedly connected to the stepped annular surface 1407 by bolts passing through the PCB board mounting holes 1402. The PCB board 16 is powered by a battery 15 installed in a battery compartment 1401. The battery compartment 1401 is installed inside the stepped housing 14, that is, symmetrically installed inside the upper housing 1405. The battery compartment 1401 is located above the PCB board 16. The PCB board 16 is electrically connected to a thin-film strain gauge 8. In this embodiment, the nominal resistance of the thin-film strain gauge 8 is 350Ω, the sensitivity coefficient of the thin-film strain gauge 8 is 2±1%, the substrate size is 3.6mm×3.1mm, and the sensitive grid size is 1.0mm×2.0mm.

[0087] Specifically, PCB board 16 includes a DC power output unit, an amplifier module, an AD conversion module, a main control module, and a wireless transmission module.

[0088] The DC power output unit of PCB board 16 outputs 3.3V voltage to power the thin-film strain gauge 8, which in turn powers the four Wheatstone bridges. The thin-film strain gauge 8 forms four Wheatstone bridges that connect to the input channels of their respective amplification modules. The amplification modules contain four independent amplification circuits that amplify millivolt-level voltage signals to the range of -5V to +5V. The output of each amplification circuit is connected to the AD conversion module. The AD conversion module performs synchronous analog-to-digital conversion on the amplified voltage signals and connects to the main control module via SPI communication. The main control module connects to the PC via a wireless transmission module, which sends the data processed by the main control unit to the external PC.

[0089] like Figure 16 As shown, the data acquisition and wireless transmission system has a 3.3V DC power output to power the four Wheatstone bridges on the strain elastic body 19. Since the voltage change of the Wheatstone bridge caused by strain is relatively weak, the voltage signal of the Wheatstone bridge is first amplified to -5V to +5V by the amplification module. Then, the AD conversion module synchronously acquires the four-channel voltage signals and performs AD conversion. The AD conversion module transmits the four-channel voltage values ​​to the main control module through SPI communication. The main control module processes the signal and sends it to the PC through the wireless transmission module. The milling force acquisition software acquires the signal to complete the online monitoring of the four-component milling force.

[0090] The scope of protection claimed by this invention is not limited to the specific embodiments described above. Moreover, for those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A four-component strain gauge milling force measuring machine tool system, characterized in that, It includes a tool holder (1), an upper connecting flange (7), a strain elastic body (19), a lower connecting flange (9), and a tool base (11) that are coaxially assembled in sequence, wherein the tool base (11) holds the tool (13). The strain elastic body (19) includes a crossbeam (1903), with a loading platform (1902) at the center of the crossbeam (1903). Each end of the crossbeam (1903) is vertically connected to a pair of double-layer cross floating beam groups (1906), and an outer ring connecting platform (1901) connects two adjacent double-layer cross floating beam groups (1906). The double-layer cross floating beam group (1906) includes two staggered front double-layer floating beams (19061) and rear double-layer floating beams (19062). Both the front double-layer floating beam (19061) and the rear double-layer floating beam (19062) include two parallel beams. The beams of the front double-layer floating beam (19061) are arranged longitudinally, and the beams of the rear double-layer floating beam (19062) are arranged transversely. The loading surface of the front double-layer floating beam (19061) is connected to the cross beam (1903), and the fixing surface of the rear double-layer floating beam (19062) is connected to the outer ring connecting platform (1901); the surface of the cross beam (1903) and the surface of the double-layer cross floating beam assembly (1906) are covered with thin film strain gauges (8) that form a Wheatstone bridge. The cross beam (1903) includes four cross beams arranged in a cross shape, namely the first cross beam, the second cross beam, the third cross beam, and the fourth cross beam. Two cross beams with attached thin film strain gauges (8) are arranged radially symmetrically along the loading platform (1902). Each front-end double-layer floating beam (19061) has a thin film strain gauge (8) attached to its outer surface. Thin film strain gauges (8) are attached to the side surfaces of the first and third crossbeams, while thin film strain gauges (8) are not attached to the second and fourth crossbeams; thin film strain gauges (8) are attached to the upper and lower outer surfaces of the rear double-layer floating beam (19062) which is connected to the second and fourth crossbeams through the front double-layer floating beam (19061). The upper end of the strain elastomer (19) is connected to the tool holder (1) via the upper connecting flange (7), and the lower end of the strain elastomer (19) is connected to the tool base (11) via the lower connecting flange (9). The lower part of the tool holder (1) is fitted with a stepped housing (14) through an upper end cover (4). A lower end cover (17) is installed on the lower end face of the stepped housing (14). A PCB board (16) carrying a data acquisition and wireless transmission system is installed inside the stepped housing (14). The PCB board (16) is powered by a battery (15) installed in a battery compartment (1401). The battery compartment (1401) is installed inside the stepped housing (14). The PCB board (16) is electrically connected to a thin film strain gauge (8).

2. The four-component strain-type milling force measuring machine tool system according to claim 1, characterized in that, The PCB board (16) includes a DC power output unit, an amplification module, an AD conversion module, a main control module, and a wireless transmission module. The DC power output unit of the PCB board (16) outputs a 3.3V voltage to power the thin film strain gauge (8). The thin film strain gauge (8) forms four Wheatstone bridges to connect the input channels of their respective amplification modules. The output of each amplification module is connected to the main control module via SPI communication through an AD conversion module. The main control module is connected to a PC through a wireless transmission module.

3. The four-component strain-type milling force measuring machine tool system according to claim 2, characterized in that, The amplification module contains four independent amplification circuits that amplify the millivolt-level voltage signal output from the Wheatstone bridge to a range of -5V to +5V for acquisition by the AD conversion module.

4. The four-component strain-type milling force measuring machine tool system according to claim 1, characterized in that, The stepped housing (14) includes an upper housing (1405) and a lower housing (1406) fixed by a stepped annular surface (1407); the lower housing (1406) is provided with an internal threaded post (1403) fixed on the stepped annular surface (1407), and the lower end cover (17) is installed on the lower end face of the lower housing (1406) by bolts that mate with the internal threaded post (1403). The stepped annular surface (1407) is evenly distributed with PCB board mounting holes (1402). The PCB board (16) is fixedly connected to the stepped annular surface (1407) by bolts passing through the PCB board mounting holes (1402). The battery compartment (1401) is symmetrically installed inside the upper housing (1405). The battery compartment (1401) is located above the PCB board (16). The upper end face of the upper housing (1405) is connected to the outer ring of the upper end cover (4) by bolts, and the inner ring of the upper end cover (4) is connected to the lower annular protrusion of the knife handle (1) by bolts.

5. The four-component strain-type milling force measuring machine tool system according to claim 4, characterized in that, The lower part of the tool handle (1) has a first stepped through hole (102) protruding, and the tool handle (1) is connected to the upper connecting flange (7) by a bolt passing through the first stepped through hole (102). The upper connecting flange (7) has four second stepped through holes (703) corresponding to the positions of the first screw holes (1904) on the four outer ring connecting platforms (1901). The upper connecting flange (7) is connected to the strain elastic body (19) by bolts passing through the second stepped through holes (703) and the first screw holes (1904) in sequence. The loading platform (1902) of the strain elastomer (19) has a second screw hole (1905) evenly opened along the circumference. The lower connecting flange (9) has a third stepped through hole (904) corresponding to the position of the second screw hole (1905). The lower connecting flange (9) is connected to the strain elastomer (19) by bolts that pass through the third stepped through hole (904) and the second screw hole (1905) in sequence. The upper annular protrusion of the tool base (11) has through holes (1102) evenly distributed around its circumference. The lower connecting flange (9) has a third screw hole (903) corresponding to the position of the through hole (1102). The tool base (11) is connected to the lower connecting flange (9) by bolts that pass through the through hole (1102) and the third screw hole (903) in sequence.

6. The four-component strain-type milling force measuring machine tool system according to claim 1, characterized in that, The lower end face of the tool holder (1) has a first positioning hole (101) that mates with the upper flange boss (701) on the upper end face of the upper connecting flange (7). The lower end face of the upper connecting flange (7) has a second positioning hole (702) that mates with the outer periphery of the outer ring connecting platform (1901) of the strain elastic body (19). The lower connecting flange (9) has an upper boss (901) and a lower boss (902) on its two ends respectively. The upper boss (901) has a third positioning hole (905) in the center that mates with the outer periphery of the loading platform (1902). The upper end face of the tool base (11) has a fourth positioning hole (1101) that mates with the lower boss (902) of the lower connecting flange (9).

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