Four-component strain type milling force measuring machine tool cutter system

Abstract

The invention relates to the technical field of intelligent manufacturing, and discloses a four-component strain type milling force measuring machine tool cutter system which comprises a cutter handle, an upper connecting flange, a strain elastic body, a lower connecting flange, a cutter base and a cutter base clamping cutter which are sequentially and coaxially assembled. A loading platform is arranged in the center of a cross-shaped cross beam of the strain elastomer, the cross-shaped cross beam is connected with double-layer cross floating beam groups, and an outer ring connecting table is connected between every two adjacent double-layer cross floating beam groups; film strain gauges combined into a Wheatstone bridge are adhered to the surfaces of the cross-shaped cross beam and the double-layer cross floating beam group; a PCB (Printed Circuit Board) loaded with a data acquisition and wireless transmission system is arranged in a stepped shell sleeved outside the knife handle; and the PCB is electrically connected with the film strain gauge. According to the invention, independent detection and dynamic calculation of four-component milling force are realized, inter-dimensional coupling is small, the structure is compact, the measurement precision is high, and the application range is wide.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent manufacturing technology, and in particular relates to the field of online measurement of milling force, and specifically relates to a four-component strain gauge milling force measurement machine tool system. Background Art

[0002] Milling force is one of the most fundamental signals that reflects milling process information and is also the most widely used signal for milling process monitoring. 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] Existing strain gauge milling force measurement systems offer advantages such as low cost, stable signals, and high reliability. However, existing systems have several challenges. These challenges stem from the structural limitations of their strain gauge elastomers, resulting in a large toolholder, making it difficult to integrate into compact machine tools. Furthermore, these systems often employ a fixed design that is incompatible with various toolholder interfaces, hindering their flexibility in actual machining processes. This significantly limits the applicability and usability of milling force measurement technology. Summary of the Invention

[0004] In order to solve a series of problems such as the existing milling force online measurement system being limited by the strain elastomer structure design, being difficult to integrate into a compact machine tool, resulting in the inability to be flexibly applied in actual machining processes, greatly limiting the scope of application and ease of use of the milling force measurement technology, the present invention provides a four-component strain milling force measurement machine tool tool system.

[0005] The present invention is implemented by the following technologies:

[0006] The present invention provides a four-component strain gauge milling force measurement machine tool tool system, comprising a tool holder, an upper connecting flange, a strain elastic body, a lower connecting flange, and a tool base that are coaxially assembled in sequence, wherein the tool base clamps the tool; the strain elastic body comprises a cross beam, a loading platform is provided in the center of the cross beam, each end of the cross beam is vertically connected to a pair of double-layer cross floating beam groups, and an outer ring connecting platform is connected between two adjacent double-layer cross floating beam groups; thin film strain gauges that are combined into a Wheatstone bridge are adhered to the surface of the cross beam and the surface of the double-layer cross floating beam group; 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 lower part of the tool holder is covered with a stepped shell through an upper end cover, the lower end surface of the stepped shell is installed with a lower end cover, a PCB board carrying a data acquisition and wireless transmission system is installed in the stepped shell, the PCB board is powered by a battery installed in a battery compartment, the battery compartment is installed in the stepped shell, and the PCB board is electrically connected to the thin film strain gauge.

[0007] During implementation, it includes a tool handle, an upper connecting flange, a strain elastic body, a lower connecting flange, and a tool base that are coaxially assembled in sequence; the upper end of the strain elastic body is connected to the tool handle 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, and the tool base clamps the tool.

[0008] To ensure coaxial assembly, a first positioning hole is opened in the center of the lower end surface of the tool handle to match the upper flange boss on the upper end surface of the upper connecting flange, that is, the first positioning hole on the lower end surface of the tool handle is engaged with the upper flange boss on the upper connecting flange.

[0009] A second positioning hole is opened in the center of the lower end face of the upper connecting flange to cooperate with the outer periphery of the outer ring connecting platform of the strain elastic body, that is, the curved outer edge of the outer ring connecting platform of the strain elastic body is a concentric arc surface, and the second positioning hole on the lower end face of the upper connecting flange cooperates with the curved outer edge of the outer ring connecting platform.

[0010] The two end surfaces of the lower connecting flange are respectively provided with an upper boss and a lower boss. A third positioning hole is opened in the center of the upper boss to cooperate with the outer periphery of the loading platform. A fourth positioning hole is opened in the center of the upper end surface of the tool base to cooperate 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, and at the same time, the lower boss of the lower connecting flange is engaged with the fourth positioning hole of the tool base.

[0011] Furthermore, a first stepped through hole is protruded from the lower ring of the knife handle, and the knife handle is connected to the upper connecting flange via bolts passing through the first stepped through hole.

[0012] The upper connecting flange is provided with four second stepped through holes corresponding to the positions of the first screw holes on the four outer ring connecting platforms. The upper connecting flange is connected to the strain elastic body by bolts passing through the second stepped through holes and the first screw holes in sequence.

[0013] A second screw hole is evenly opened along the circumference of the loading platform of the strain elastic body, and a third stepped through hole corresponding to the position of the second screw hole is opened on the lower connecting flange. The lower connecting flange is connected to the strain elastic body by bolts that pass through the third stepped through hole and the second screw hole in sequence.

[0014] The upper ring convex of the tool base is uniformly distributed with through holes along the circumference, and the lower connecting flange is provided with a third screw hole corresponding to the position of the through holes. The tool base is connected to the lower connecting flange by bolts passing through the through holes and the third screw holes in sequence.

[0015] The strain elastomer comprises a cross beam, a loading platform is arranged in the center of the cross beam, a pair of double-layer cross floating beam groups are vertically connected to each end of the cross beam, an outer ring connecting table is connected between two adjacent double-layer cross floating beam groups, the double-layer cross floating beam group comprises two staggered front double-layer floating beams and rear double-layer floating beams, the loading surface of the front double-layer floating beam is connected with the cross beam, and the fixing surface of the rear double-layer floating beam is connected with the outer ring connecting table; in order to realize the milling process 、 、 、 The surface of the cross beam and the surface of the double-layer cross floating beam group are pasted with thin film strain gauges combined into a Wheatstone bridge, the front double-layer floating beam and the rear double-layer floating beam each comprise two mutually parallel beam bodies, the outer surface of the beam body is pasted with a thin film strain gauge, and specifically, the outer side surface of each front double-layer floating beam is pasted with a thin film strain gauge.

[0016] The cross beam comprises four cross-arranged cross beams, namely a first cross beam, a second cross beam, a third cross beam and a fourth cross beam, and the side surfaces of only two cross beams are pasted with thin film strain gauges; the two cross beams pasted with the thin film strain gauges are arranged in a radial symmetry along the loading platform, that is, the side surfaces of the first cross beam and the third cross beam are pasted with the thin film strain gauges, and the remaining two cross beams, namely the second cross beam and the fourth cross beam, are not pasted with the thin film strain gauges.

[0017] The upper and lower outer surfaces of the rear double-layer floating beam are pasted with thin film strain gauges, and the two double-layer cross floating beam groups in which the rear double-layer floating beam pasted with the thin film strain gauges is arranged are connected with the cross beams not pasted with the thin film strain gauges, that is, the upper and lower outer surfaces of the rear floating beam connected with the second cross beam and the fourth cross beam are pasted with the thin film strain gauges.

[0018] The thin film strain gauges are divided into four groups to detect the surface strain caused by the milling force, and correspond to 、 、 、 The detection of the four-component milling force, and then the voltage change is formed to represent the change of the milling force, so that the voltage signal output of the strain gauge is realized.

[0019] The lower part of the tool shank is sleeved with a stepped shell through an upper end cover, the stepped shell comprises an upper shell and a lower shell fixed through a stepped ring surface, the upper end surface of the upper shell is connected with the outer ring of the upper end cover through a bolt, and the inner ring of the upper end cover is connected with the lower part of the tool shank through a bolt; the lower end surface of the stepped shell is provided with a lower end cover, that is, the lower shell is provided with an inner hole threaded column fixed on the stepped ring surface, and the lower end cover is installed on the lower end surface of the lower shell through a bolt matched with the inner hole threaded column.

[0020] The stepped shell is internally provided with a PCB board loaded with a data acquisition and wireless transmission system, i.e., a stepped ring surface is uniformly provided with PCB board mounting holes, the PCB board is fixedly connected with the stepped ring surface through bolts penetrating through the PCB board mounting holes, the PCB board is powered by a battery installed in a battery compartment, the battery compartment is installed in the stepped shell, i.e., the battery compartment is symmetrically installed in the upper shell and is located above the PCB board; and the PCB board is electrically connected with the thin film strain gauge.

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

[0022] The DC power output unit of the PCB board outputs a 3.3V voltage to power the thin film strain gauge, i.e., to power four Wheatstone bridges, the thin film strain gauge is connected with the input channels of the respective amplification modules by forming four Wheatstone bridges, the amplification module comprises four independent amplification circuits, the millivolt-level voltage signals output by the Wheatstone bridges are amplified to a range of -5V to +5V to be collected by the AD conversion module, the AD conversion module synchronously collects the voltage signals amplified by the amplification module through the four amplification circuits; the output end of each amplification module is connected with the main control module through the AD conversion module by using SPI communication, and the main control module is connected with a PC through the wireless transmission module; i.e., the output end of each amplification circuit is connected to the AD conversion module, the AD conversion module synchronously converts the amplified voltage signals into digital signals and is connected with the main control module by using SPI communication, the main control module is connected with the PC through the wireless transmission module, and the wireless transmission module sends the data processed by the main control unit to the external PC.

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

[0024] The four-component strain type milling force measuring machine tool system provided by the application adopts a double-layer cross floating beam group and a cross beam composite strain elastomer structure, greatly reduces the overall volume through spatial optimization layout, solves the problem of excessive volume of traditional force gauges due to structural redundancy, and can be directly integrated into a standard machine tool system without the need to modify the processing environment.

[0025] The application measures the milling force of the tool system through the strain elastomer and the modularly designed components, wherein the tool shank, the upper connecting flange, the strain elastomer, the lower connecting flange and the tool base are assembled in series through hole cooperation and bolt connection, high coaxiality assembly is ensured, the dependence on installation accuracy is reduced, the system stability is improved, the circuit system and the tool shank are connected, milling force signal acquisition and wireless transmission are realized, the outer ring connecting table of the strain elastomer is designed through bolt and screw hole cooperation, high coaxiality assembly is ensured, the dependence on installation accuracy is reduced, and the system stability is improved; different tool shanks and tool bases can be connected by replacing different upper connecting flanges and lower connecting flanges, so as to adapt to different processing scenes.

[0026] The application is based on four groups of Wheatstone full-bridge circuits composed of twenty thin film strain gauges, and realizes independent detection and dynamic calculation of four-component milling forces by combining the mechanical decoupling design of double-layer cross floating beam group and cross beam, the inter-group coupling is small, the structure is compact, and the problems of low measurement accuracy and limited application range of the existing milling force measurement technology are solved.

[0027] The application has reasonable structure and ingenious design, effectively solves the problems of large size and limited application range of the existing strain type wireless rotary force meter, and is suitable for milling processing in various occasions, such as laboratory, production site and the like. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a perspective structural schematic diagram of the application.

[0029] Figure 2 is an explosion view of the application.

[0030] Figure 3 is a sectional view of the application.

[0031] Figure 4 is a structural schematic diagram of the tool shank 1 in the application.

[0032] Figure 5 is a half-sectional view of the tool shank 1 in the application.

[0033] Figure 6 is a top view of the tool shank 1 in the application.

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

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

[0036] Figure 9 is a perspective structural schematic diagram of the strain elastic body 19 in the application.

[0037] Figure 10 is a structural schematic diagram of the double-layer cross floating beam group 1906 in the application.

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

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

[0040] Figure 13 is a half-sectional view of the tool holder 11 in the application.

[0041] Figure 14 is a top view of the tool holder 11 in the application.

[0042] Figure 15 It is a bottom view of the stepped housing 14 of the present invention.

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

[0044] Figure 17 Schematic diagram of the arrangement of the thin film strain gauge 8 in the present invention.

[0045] Figure 18 Schematic diagram of the installation of the thin film strain gauge 8 on the strain elastic body 19 in the present invention.

[0046] Figure 19 The present invention comprises four Wheatstone bridges for detecting milling forces, formed by strain gauges.

[0047] In the figure: 1-handle; 101-first positioning hole; 102-first stepped through hole; 103-fifth screw hole; 2-first bolt; 3-second bolt; 4-upper end cover; 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-thin 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 film strain gauge; 806 - sixth film strain gauge; 807 - seventh film strain gauge; 808 - eighth film strain gauge; 809 - ninth film strain gauge; 810 - tenth film strain gauge; 811 - eleventh film strain gauge; 812 - twelfth film strain gauge; 813 - thirteenth film strain gauge; 814 - fourteenth film strain gauge; 815 - fifteenth film strain gauge; 816 - sixteenth film strain gauge; 817 - seventeenth film strain gauge; 818 - eighteenth film strain gauge Membrane strain gauge; 819-19th membrane strain gauge; 820-20th membrane 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 base; 1101-fourth positioning hole; 1102-through hole; 12-sixth bolt; 13-tool; 14-step housing; 1401-battery compartment; 1402-PCB board mounting hole; 1403-inner screw Column; 1404-upper end cover connection hole; 1405-upper shell; 1406-lower shell; 1407-step annulus; 15-battery; 16-PCB board; 17-lower end cover; 18-seventh bolt, 19-strain elastomer; 1901-outer ring connection platform; 1902-loading platform; 1903-cross beam; 1904-first screw hole; 1905-second screw hole; 1906-double-layer cross floating beam group, 19061-front section double-layer floating beam; 19062-rear section double-layer floating beam. DETAILED DESCRIPTION

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

[0049] A four-component strain gauge milling force measurement system for machine tools, such as Figures 1 to 18 As shown, it includes a tool handle 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; the upper end of the strain elastic body 19 is connected to the tool handle 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, and the tool base 11 clamps the tool 13.

[0050] To ensure coaxial assembly, a first positioning hole 101 is opened in the center of the lower end surface of the shank 1 to cooperate with the upper flange boss 701 on the upper end surface of the upper connecting flange 7, that is, the first positioning hole 101 on the lower end surface of the shank 1 is engaged 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 to cooperate with the outer periphery of the outer ring connecting platform 1901 of the strain elastic body 19, that is, the curved outer edge of the outer ring connecting platform 1901 of the strain elastic body 19 is a concentric arc surface, and the second positioning hole 702 on the lower end face of the upper connecting flange 7 cooperates with the curved outer edge of the outer ring connecting platform 1901.

[0052] like Figure 11 、 12 As shown, the two end surfaces of the lower connecting flange 9 are respectively provided with an upper boss 901 and a lower boss 902, and the center of the upper boss 901 is provided with a third positioning hole 905 that cooperates with the outer periphery of the loading platform 1902, and the center of the upper end surface of the tool base 11 is provided with a fourth positioning hole 1101 that cooperates 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, and at the same time, 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 handle 1 adopts a BT40 handle, and the lower part of the handle 1 is covered with a stepped housing 14 through the upper end cover 4. Figure 15 As shown, the stepped shell 14 includes an upper shell 1405 and a lower shell 1406 fixed by a step annular surface 1407. The upper end surface of the upper shell 1405 is provided with an upper end cover connecting hole 1404. The upper end cover 4 is installed on the upper end surface of the upper shell 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 is located at the interval of the first stepped through hole 102 and has six fifth screw holes 103. 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 hole 103; the lower end surface of the stepped shell 14 is provided with a lower end cover 17, that is, three inner hole threaded columns 1403 fixed on the step annular surface 1407 are provided in the lower shell 1406, and the lower end cover 17 is installed on the lower end surface of the lower shell 1406 by a seventh bolt 18 cooperating with the inner hole threaded column 1403.

[0054] like Figures 4-6As shown in Figures 8 and 8, the lower part of the tool handle 1 is provided with a lower annular bulge, and the lower annular bulge has six first stepped through holes 102 opened in the axial direction. The six first stepped through holes 102 are evenly arranged along the circumferential direction. Fourth screw holes 704 are opened at corresponding positions of the upper connecting flange 7 and the first stepped through holes 102. The tool handle 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 holes 704 in sequence.

[0055] like Figures 8-10 As shown, the outer ring connecting platform 1901 of the strain elastic body 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 elastic body 19 by a fourth bolt 6 that passes through the second stepped through hole 703 and the first screw hole 1904 in sequence.

[0056] Six second screw holes 1905 are evenly arranged along the circumference on the loading platform 1902 of the strain elastic body 19, and six third stepped through holes 904 corresponding to the positions of the second screw holes 1905 are arranged on the lower connecting flange 9. The lower connecting flange 9 is connected to the strain elastic body 19 by a fifth bolt 10 that passes through the third stepped through holes 904 and the 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 bulge, and the upper annular bulge has four through holes 1102 evenly distributed along the circumference, and 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 cross beam 1903, which includes four cross beams arranged in a cross shape, namely the first beam, the second beam, the third beam, and the fourth beam. In this embodiment, the first beam and the third beam are in the Y direction, and the second beam and the fourth beam are in the X direction.

[0059] A loading platform 1902 is provided in the center of the cross beam 1903, and each end of the cross beam 1903 is vertically connected to a pair of double-layer cross floating beam groups 1906, and an outer ring connecting platform 1901 is connected between two adjacent double-layer cross floating beam groups 1906. The double-layer cross floating beam group 1906 includes two staggered front-section double-layer floating beams 19061 and rear-section double-layer floating beams 19062. The loading surface of the front-section double-layer floating beam 19061 is connected to the cross beam 1903, and the fixed surface of the rear-section double-layer floating beam 19062 is connected to the outer ring connecting platform 1901; in order to realize the milling process 、 、 、 For the measurement of four-component milling force, thin film strain gauges 8 that form a Wheatstone bridge are pasted on the surface of the cross beam 1903 and the surface of the double-layer cross floating beam group 1906. The front double-layer floating beam 19061 and the rear double-layer floating beam 19062 both include two parallel beam bodies, and thin film strain gauges 8 are pasted on the outer surfaces of the beam bodies. The beam body of the front double-layer floating beam 19061 is arranged longitudinally, and the beam body of the rear double-layer floating beam 19062 is arranged transversely.

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

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

[0062] Thin film strain gauges 8 are pasted on the upper and lower outer surfaces of the rear double-layer floating beam 19062 connected to the second beam and the fourth beam through 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 the milling forces in the X, Y and Z directions. When the loading platform 1902 is subjected to X / Y direction forces, the front double-layer floating beam 19061 in the X / Y direction is strained; when the loading platform 1902 is subjected to Z direction forces, the rear double-layer floating beam 19062 in the Z direction is strained; the cross beam 1903 is a force measuring unit for Z-direction torque. When the loading platform 1902 is subjected to Z-direction torque, the four beams are strained.

[0064] The thin film strain gauges 8 are divided into four groups to detect the surface strain caused by the milling force, corresponding to 、 、 、 The four-component milling force is detected, and then a voltage change is formed to characterize the milling force change, thereby realizing the voltage signal output of the strain gauge.

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

[0066] The outer sides of the two front 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 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 first thin film strain gauge 801 and the third thin film strain gauge 803 are respectively attached to the outer sides of the two front double-layer floating beams 19061 connected to the end of the second crossbeam. The second thin film strain gauge 802 and the fourth thin film strain gauge 804 are respectively attached to the outer sides of the two front double-layer floating beams 19061 connected to the end of the fourth crossbeam.

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

[0069] When the loading platform 1902 is subjected to a positive force in the X direction, the first film strain gauge 801 and the third film strain gauge 803 are compressed, and the second film strain gauge 802 and the fourth film strain gauge 804 are stretched. Conversely, when the loading platform 1902 is subjected to a negative force in the X direction, the first film strain gauge 801 and the third film strain gauge 803 are stretched, and the second film strain gauge 802 and the fourth film strain gauge 804 are compressed. The strains generated by the four film strain gauges 8 are recorded as 、 、 、 .

[0070] When the loading platform 1902 is subjected to a positive force in the Y direction, the fifth and seventh film strain gauges 805 and 807 are compressed, and the sixth and eighth film strain gauges 806 and 808 are stretched. Conversely, when the loading platform 1902 is subjected to a negative force in the Y direction, the fifth and seventh film strain gauges 805 and 807 are stretched, and the sixth and eighth film strain gauges 806 and 808 are compressed. The strains generated by the four film strain gauges 8 are recorded as 、 、 、 .

[0071] When the loading platform 1902 is subjected to a positive Z force, the tenth film strain gauge 810, the twelfth film strain gauge 812, the fourteenth film strain gauge 814, and the sixteenth film strain gauge 816 are compressed, and the ninth film strain gauge 809, the eleventh film strain gauge 811, the thirteenth film strain gauge 813, and the fifteenth film strain gauge 815 are stretched. Conversely, when the loading platform 1902 is subjected to a negative Z force, the tenth film strain gauge 810, the twelfth film strain gauge 812, the fourteenth film strain gauge 814, and the sixteenth film strain gauge 816 are stretched, and the ninth film strain gauge 809, the eleventh film strain gauge 811, the thirteenth film strain gauge 813, and the fifteenth film strain gauge 815 are compressed. The strains generated by the eight film strain gauges 8 are recorded as 、 、 、 、 、 、 、 .

[0072] When the loading platform 1902 is subjected to a positive Z moment, the eighteenth and twentieth film strain gauges 818 and 820 are compressed, and the seventeenth and nineteenth film strain gauges 817 and 819 are stretched. Conversely, when the loading platform 1902 is subjected to a negative Z moment, the eighteenth and twenty film strain gauges 818 and 820 are stretched, and the seventeenth and nineteenth film strain gauges 817 and 819 are compressed. The strains generated by the four film strain gauges 8 are recorded as 、 、 、 .

[0073] like Figure 19 As shown, the strain values ​​measured by the strain gauges at various positions of the strain elastic body The relationship between the strain value output by the Wheatstone full bridge under various external forces is 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 four Wheatstone bridges 、 、 、 Signal and strain elastic body strain value 、 、 、 There are the following relationships:

[0076]

[0077] Where, is the sensitivity coefficient of the strain gauge.

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

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

[0080]

[0081] Where, is the tensile pressure in the X direction.

[0082] is the tensile pressure in the Y direction.

[0083] is the tensile pressure in the Z direction.

[0084] is the Z-direction moment.

[0085] It is the calibration matrix obtained after the tool holder 1 is calibrated by the force calibration device.

[0086] A PCB board 16 carrying a data acquisition and wireless transmission system is installed in the stepped housing 14, that is, PCB board mounting holes 1402 are evenly distributed on the stepped annular surface 1407, and 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, and the battery compartment 1401 is installed in the stepped housing 14, that is, the battery compartment 1401 is symmetrically installed in the upper housing 1405, and the battery compartment 1401 is located above the PCB board 16; the PCB board 16 is electrically connected to the 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 base size is 3.6mm×3.1mm, and the sensitive grid size is 1.0mm×2.0mm.

[0087] Specifically, 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:

[0088] The DC power output unit of the PCB board 16 outputs a 3.3V voltage to power the thin film strain gauge 8, that is, to power the four Wheatstone bridges. The thin film strain gauge 8 forms four Wheatstone bridges to connect the input channels of their respective amplifier modules. The amplifier module includes four independent amplifier circuits, which amplify the millivolt voltage signal to the range of -5V to +5V. The output end of each amplifier circuit is connected to the AD conversion module. The AD conversion module performs synchronous analog-to-digital conversion on the amplified voltage signal and connects to the main control module via SPI communication. The main control module is connected to the PC via the wireless transmission module, and the wireless transmission module 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 by the amplifier module to -5V to +5V, and then the AD conversion module synchronously collects 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 signals and sends them to the PC through the wireless transmission module. The signals are collected by the milling force acquisition software to complete the online monitoring of the four-component milling force.

[0090] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various variations and modifications. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A four-component strain gauge milling force measurement system for machine tools, characterized in that: It comprises a tool handle (1), an upper connecting flange (7), a strain elastic body (19), a lower connecting flange (9), and a tool base (11) which are coaxially assembled in sequence, wherein the tool base (11) clamps the tool (13); The strain elastic body (19) includes a cross beam (1903), a loading platform (1902) is provided at the center of the cross beam (1903), each end of the cross beam (1903) is vertically connected to a pair of double-layer cross floating beam groups (1906), and an outer ring connecting platform (1901) is connected between two adjacent double-layer cross floating beam groups (1906); thin film strain gauges (8) combined into a Wheatstone bridge are attached to the surface of the cross beam (1903) and the surface of the double-layer cross floating beam groups (1906); The upper end of the strain elastic body (19) is connected to the tool handle (1) via an upper connecting flange (7), and the lower end of the strain elastic body (19) is connected to the tool base (11) via a lower connecting flange (9). The lower portion of the shank (1) is sleeved with a stepped housing (14) via an upper end cover (4); a lower end cover (17) is mounted on the lower end surface of the stepped housing (14); a PCB board (16) carrying a data acquisition and wireless transmission system is mounted in the stepped housing (14); the PCB board (16) is powered by a battery (15) mounted in a battery compartment (1401); the battery compartment (1401) is mounted in the stepped housing (14); and the PCB board (16) is electrically connected to a thin film strain gauge (8).

2. A four-component strain gauge milling force measurement machine tool system according to claim 1, characterized in that: The double-layer cross floating beam group (1906) includes two staggered front double-layer floating beams (19061) and rear double-layer floating beams (19062), the loading surface of the front double-layer floating beam (19061) is connected to the cross beam (1903), and the fixed surface of the rear double-layer floating beam (19062) is connected to the outer ring connecting platform (1901).

3. The four-component strain gauge milling force measurement system for machine tools 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 the respective amplifier modules. The output end of each amplifier module is connected to the main control module via the AD conversion module using SPI communication. The main control module is connected to the PC via the wireless transmission module.

4. A four-component strain gauge milling force measurement machine tool system according to claim 3, characterized in that: The amplification module includes four independent amplification circuits, which amplify the millivolt voltage signal output by the Wheatstone bridge to a range of -5V to +5V for acquisition by the AD conversion module.

5. The four-component strain gauge milling force measurement system for machine tools according to claim 1, characterized in that: The stepped housing (14) comprises an upper housing (1405) and a lower housing (1406) fixed by a stepped annular surface (1407); an inner hole threaded column (1403) fixed on the stepped annular surface (1407) is provided in the lower housing (1406); the lower end cover (17) is mounted on the lower end surface of the lower housing (1406) by means of bolts that cooperate with the inner hole threaded column (1403). PCB board mounting holes (1402) are evenly distributed on the step annular surface (1407), the PCB board (16) is fixedly connected to the step annular surface (1407) by bolts passing through the PCB board mounting holes (1402), and a battery compartment (1401) is symmetrically installed in the upper shell (1405), and the battery compartment (1401) is located above the PCB board (16); The upper end surface of the upper shell (1405) is connected to the outer ring of the upper end cover (4) via bolts, and the inner ring of the upper end cover (4) is connected to the lower annular protrusion of the shank (1) via bolts.

6. A four-component strain gauge milling force measurement machine tool system according to claim 5, characterized in that: A first stepped through hole (102) is formed in a convex ring at the lower portion of the knife handle (1), and the knife handle (1) is connected to the upper connecting flange (7) via a bolt passing through the first stepped through hole (102); The upper connecting flange (7) is provided with four second stepped through holes (703) corresponding to the positions of the first screw holes (1904) on the four outer ring connecting platforms (1901), and 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 elastic body (19) is provided with second screw holes (1905) uniformly along the circumferential direction, the lower connecting flange (9) is provided with a third stepped through hole (904) corresponding to the position of the second screw hole (1905), and the lower connecting flange (9) is connected to the strain elastic body (19) by bolts passing through the third stepped through hole (904) and the second screw hole (1905) in sequence; The upper annular projection of the tool base (11) is provided with through holes (1102) uniformly distributed along the circumferential direction, and the lower connecting flange (9) is provided with 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 passing through the through hole (1102) and the third screw hole (903) in sequence.

7. The four-component strain gauge milling force measurement system for machine tools according to claim 1, characterized in that: A first positioning hole (101) is provided at the center of the lower end surface of the shank (1) and is engaged with the upper flange boss (701) on the upper end surface of the upper connecting flange (7); A second positioning hole (702) is provided in the center of the lower end surface of the upper connecting flange (7) and is matched with the outer periphery of the outer ring connecting platform (1901) of the strain elastic body (19); An upper boss (901) and a lower boss (902) are respectively provided on both end surfaces of the lower connecting flange (9), and a third positioning hole (905) is provided in the center of the upper boss (901) to cooperate with the outer periphery of the loading platform (1902); A fourth positioning hole (1101) is provided in the center of the upper end surface of the tool base (11) and is engaged with the lower boss (902) of the lower connecting flange (9).

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