Length measuring equipment based on laser interference

Abstract

The invention relates to the technical field of length measurement, and particularly discloses a length measurement device based on laser interference, which comprises a laser measurement module, an air curtain channel module, an air curtain construction module and a channel adjustment module, the laser measuring module is used for transmitting and receiving laser, the optical path difference change is measured according to the interference principle, and the micro length change of the workpiece can be continuously and accurately measured in real time while the machining module carries out machining operation on the workpiece; a linear channel is formed between the laser head and the measuring reflector through the air curtain channel module, inert gas is continuously introduced into the channel through the air curtain construction module, and an air curtain atmosphere with stable laminar flow is formed, so that pollutants and interference factors such as oil mist, dust, cutting fluid splashing and hot air turbulence generated in a machining area are effectively blocked, and the machining precision is improved. Therefore, the measurement light beam is prevented from being interfered by environmental factors in the propagation process.

Description

TECHNICAL FIELD

[0001] The present application relates to the length measurement technical field, more particularly, it relates to a length measurement device based on laser interference. BACKGROUND

[0002] In the field of precision machining, laser interference measurement technology is widely used in real-time deformation monitoring of workpiece machining process due to its nanometer-level precision; however, in the actual machining environment, laser interference measurement is disturbed by machining pollution interference light path, and pollutants such as cutting fluid splashing, metal dust and oil mist will directly invade the laser propagation path, causing beam scattering, attenuation or refractive index mutation, resulting in distortion or even interruption of the measurement signal; in addition, air turbulence and thermal disturbance are also unfavorable factors affecting laser interference measurement. The temperature gradient (such as tool friction heat, cooling liquid temperature difference) in the machining area causes the change of air density, generates random thermal turbulence, and the airflow disturbance caused by equipment movement, which significantly changes the air refractive index, introduces uncontrollable optical path error, and seriously reduces the precision of laser interference measurement. SUMMARY

[0003] In order to overcome the above technical problems, the present application provides a length measurement device based on laser interference.

[0004] The purpose of the present application can be achieved by the following technical solutions: A length measurement device based on laser interference is applied to a machining unit, the machining unit includes a tooling module for clamping a workpiece and a machining module for machining the workpiece; the length measurement device includes: A laser measurement module includes a mounting plate arranged on the machining module and a measurement mirror attached to the workpiece, the mounting plate is provided with a laser head matched with the measurement mirror, and the laser head is internally provided with a reference measurement mirror; A sealing sleeve is arranged outside the laser head; An air curtain passage module is arranged on the sealing sleeve for forming an air curtain passage between the laser head and the measurement mirror; An air curtain construction module is arranged on the sealing sleeve for constructing an air curtain atmosphere in the air curtain passage; A passage adjusting module is arranged outside the air curtain passage module for adjusting the length of the air curtain passage.

[0005] As a further scheme of the present application, the air curtain passage module includes a bellows arranged on the lower end surface of the sealing sleeve and an elastic air curtain diaphragm coaxially arranged in the bellows, the upper end of the elastic air curtain diaphragm is telescopically arranged in the sealing sleeve, and the lower end of the elastic air curtain diaphragm is fixedly connected with the lower end of the bellows.

[0006] As a further scheme of the present application, the sealing sleeve is internally provided with an annular sliding groove, a sliding ring is embedded in the annular sliding groove, and a plurality of traction springs connected with the sliding ring are circumferentially arranged in the annular sliding groove.

[0007] As a further scheme of the present application, the lower end of the bellows is provided with a conical cover, and a flow guide cover is arranged on the inner side of the conical cover.

[0008] As a further scheme of the present application, the air curtain construction module comprises an air cavity arranged in the sealing sleeve, a plurality of air injection ports in communication with the air curtain channel are circumferentially arranged on the inner side of the air cavity, and an air pipe is in communication with the outer side of the air cavity.

[0009] As a further scheme of the present application, the channel adjusting module comprises a mounting sleeve arranged on the mounting plate and a bearing seat arranged on the conical cover, a threaded rod is rotatably arranged in the bearing seat, the threaded rod is threaded through the mounting sleeve, and a crank handle is arranged on the upper end of the threaded rod.

[0010] As a further scheme of the present application, the anti-condensation module further comprises a driving motor fixed to the mounting plate and a tooth ring rotatably embedded in the sealing sleeve, a gear wheel engaged with the tooth ring is arranged on the output end of the driving motor, a wiper blade is fixed to the lower end of the tooth ring through a connecting frame, and the wiper blade is attached to the inner wall of the elastic air curtain diaphragm.

[0011] As a further scheme of the present application, the inner side of the conical cover is provided with an annular drainage plate matched with the elastic air curtain diaphragm, a drainage groove is formed between the annular drainage plate and the elastic air curtain diaphragm, and a drainage flow channel in communication with the bottom of the drainage groove is arranged in the conical cover.

[0012] As a further scheme of the present application, the tool module comprises a magnetic attraction plate for magnetically attracting and fixing the lower end surface of the workpiece, and an inner support assembly for radially expanding and fixing the inner wall of the workpiece is arranged on the magnetic attraction plate.

[0013] As a further scheme of the present application, the inner support assembly comprises a clamping air cylinder mounted in the magnetic attraction plate and a plurality of groups of inner support plates circumferentially distributed on the periphery of the clamping air cylinder, a lifting platform is arranged on the output end of the clamping air cylinder, and a connecting rod is hingedly connected between the lifting platform and each inner support plate.

[0014] The present application has the following advantages: The present application can accurately measure the micro-length change of the workpiece in real time and continuously while the machining module is machining the workpiece by emitting and receiving laser through the laser measurement module and measuring the change of optical path difference by using the interference principle. An air curtain channel module forms a straight channel between the laser head and the measuring reflector, and an air curtain construction module continuously introduces inert gas into the channel to form a laminar and stable air curtain atmosphere, thereby effectively blocking pollutants and interference factors such as oil mist, dust, cutting fluid splash, and hot air turbulence generated in the processing area, preventing them from entering the laser path and ensuring that the measuring beam is not disturbed by environmental factors during its propagation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] Figure 1 It is a structural schematic diagram of the present invention and the machining unit; Figure 2 A schematic structural diagram of the present invention and the machining unit from another perspective; Figure 3 It is a structural schematic diagram of the present invention; Figure 4 It is a schematic diagram of the local structure of the present invention; Figure 5 Schematic diagram of the internal structure of the air curtain channel module of the present invention; Figure 6 for Figure 5 Enlarged view of point A in the middle; Figure 7 for Figure 5 Enlarged view of point B in the middle; Figure 8 It is a structural diagram of the machining unit; Figure 9 It is a structural diagram of the tooling module; Figure 10 for Figure 9 Enlarged view of point C in the middle.

[0017] In the picture: 100, laser measurement module; 110, mounting plate; 120, laser head; 130, measurement reflector; 200, sealing sleeve; 300, air curtain channel module; 310, bellows; 320, conical cover; 330, elastic air curtain diaphragm; 340, annular chute; 350, slip ring; 360, traction spring; 370, annular guide plate; 380, drainage channel; 390, deflector cover; 400, air curtain construction module; 410, air cavity; 420, air jet; 430, air pipe; 500, channel adjustment module; 510, bearing seat; 520, threaded rod; 530, mounting sleeve; 540, crank; 600, Anti-condensation module; 610, Driving motor; 620, Gear; 630, Gear ring; 640, Connecting frame; 650, Scraper; 700, Tooling module; 710, Magnetic plate; 720, Inner support assembly; 721, Clamping cylinder; 722, Lifting platform; 723, Inner support plate; 724, Connecting rod; 800, Machining module; 810, Horizontal moving part; 811, Horizontal moving guide rod; 812, Horizontal moving sliding block; 813, Horizontal moving motor; 814, Horizontal moving screw; 820, Vertical moving part; 821, Vertical moving guide rod; 822, Vertical moving sliding block; 823, Vertical moving motor; 824, Vertical moving screw; 830, Lifting part; 831, Lifting guide rod; 832, Lifting sliding block; 833, Lifting motor; 834, Lifting screw; 840, Machining part; 841, Machining motor; 842, Milling disc; 900, Workpiece. DETAILED DESCRIPTION

[0018] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is merely meant to provide a better understanding of the subject matter described herein and can be changed in function and arrangement without departing from the scope of the disclosure. Various examples can omit, substitute, or add various procedures or components as appropriate. Also, features described with respect to some examples can be combined in other examples.

[0019] Referring now to Figure 1 and Figure 2 a length measurement device based on laser interference is disclosed, which is applied to a machining unit, the machining unit comprising a tooling module 700 for clamping a workpiece 900 and a machining module 800 for machining the workpiece 900; Referring now to Figure 3 and Figure 4The length measuring device comprises a laser measuring module 100, a sealing sleeve 200, an air curtain channel module 300, an air curtain construction module 400 and a channel adjusting module 500, the laser measuring module 100 comprises a mounting plate 110 arranged on a machining module 800 and a measuring mirror 130 attached to a workpiece 900, the mounting plate 110 is provided with a laser head 120 matched with the measuring mirror 130, and the laser head 120 is internally provided with a reference measuring mirror (not shown in the figure); the sealing sleeve 200 is arranged outside the laser head 120; the air curtain channel module 300 is arranged on the sealing sleeve 200 and used for forming an air curtain channel between the laser head 120 and the measuring mirror 130; the air curtain construction module 400 is arranged on the sealing sleeve 200 and used for constructing an air curtain atmosphere in the air curtain channel; and the channel adjusting module 500 is arranged outside the air curtain channel module 300 and used for adjusting the length of the air curtain channel. Specifically, the workpiece 900 is clamped and fixed by the tool module 700, the measuring mirror 130 is attached to the upper end surface of the workpiece 900, the air curtain channel module 300 is adjusted by the channel adjusting module 500, so that the lower end cover of the air curtain channel module 300 is arranged outside the periphery of the measuring mirror 130, a straight air curtain channel connecting the laser head 120 and the measuring mirror 130 is formed, and then the laminar stable air curtain atmosphere is formed in the air curtain channel by continuously introducing the inert gas such as nitrogen into the air curtain channel by the air curtain construction module 400, so as to prevent the interference on the laser path. When the machining module 800 performs machining work on the workpiece 900, the laser emitted by the laser head 120 is divided into a reference beam and a measuring beam by an internal beam splitter, the reference beam is vertically emitted to the fixed reference mirror and reflected back to the beam splitter, and the measuring beam is vertically emitted to the measuring mirror 130 fixed on the workpiece 900 through the stable air curtain atmosphere in the air curtain channel and reflected back to the beam splitter; the two reflected beams meet again at the beam splitter and interfere, and the micro length change of the workpiece 900 in the machining process can be accurately measured by calculating the optical path difference change of the two coherent beams.

[0020] It should be noted that the laser measuring module 100 emits and receives laser, and measures the optical path difference change by using the interference principle, so that the micro length change of the workpiece 900 can be accurately measured in real time and continuously while the machining module 800 performs machining work on the workpiece 900. The air curtain channel module 300 forms a straight channel between the laser head 120 and the measuring mirror 130, and the inert gas is continuously introduced into the channel by the air curtain construction module 400 to form a laminar stable air curtain atmosphere, so as to effectively block the oil mist, dust, cutting fluid splashing, heat flow turbulence and other pollutants and interference factors generated in the machining area, prevent them from entering the laser path, and ensure that the measuring beam is not disturbed by environmental factors in the propagation process. The stable inert gas curtain atmosphere has more stable density and refractive index than air, which minimizes the optical path error and beam drift caused by air disturbance, temperature gradient, humidity change and other factors, and provides a highly stable optical environment for laser interferometry, thereby ensuring extremely high measurement accuracy and reliability. The sealing sleeve 200 is arranged outside the laser head 120, and the gas curtain passage module 300 covers the measurement mirror 130, thereby forming a relatively closed measurement light path space, which further enhances the protection against external pollution and disturbance.

[0021] In an embodiment, referring to Figure 4 and Figure 5 , the gas curtain passage module 300 includes a bellows 310 mounted on the lower end surface of the sealing sleeve 200 and an elastic gas curtain diaphragm 330 coaxially distributed in the bellows 310, the upper end of the elastic gas curtain diaphragm 330 is telescopically arranged in the sealing sleeve 200, and the lower end of the elastic gas curtain diaphragm 330 is fixedly connected with the lower end of the bellows 310. Specifically, the elastic gas curtain diaphragm 330 forms a straight gas curtain passage inside, and the bellows 310 wraps and protects the elastic gas curtain diaphragm 330 to prevent the straight gas curtain passage from being deformed due to external environmental interference; the bellows 310 can be telescopically adjusted according to the distance between the laser head 120 and the measurement mirror 130, and during the telescopically adjusting process of the bellows 310 driven by the passage adjusting module 500, the elastic gas curtain diaphragm 330 inside can be elastically deformed in the axial direction to always maintain a straight state, so that the straight extension of the internal gas curtain passage can be maintained regardless of the length change of the gas curtain passage, thereby keeping the gas atmosphere in each region of the gas curtain passage consistent and improving the accuracy of the beam propagation path.

[0022] It should be noted that the elastic gas curtain diaphragm 330 forms a straight gas curtain passage inside, and the elastic gas curtain diaphragm 330 can always maintain a straight state when the bellows 310 is telescopically adjusted by the passage adjusting module 500 to adapt to different distances, so as to ensure that the internal passage always maintains a straight extension regardless of the length change of the gas curtain passage, thereby providing a straight propagation path for the light beam; The straight and stable gas curtain passage enables the inert gas introduced by the gas curtain construction module 400 to form a consistent gas atmosphere (density, flow rate, and laminar flow characteristics) in each region of the passage, and the uniform and stable atmosphere effectively improves the accuracy and reliability of the laser measurement beam (from the laser head 120 to the measurement mirror 130 and back) propagating in the passage, thereby reducing the optical path deviation caused by the change of the passage shape or uneven gas flow; The bellows 310 is coaxially distributed outside the elastic air curtain diaphragm 330, and the bellows 310 is wrapped and protected. The rigidity or semi-rigidity structure of the bellows 310 can effectively resist the interference of the external environment (such as splashing cutting fluid, accidental collision or air flow impact), and prevent the elastic air curtain diaphragm 330 and the straight air curtain channel inside from being deformed or damaged unexpectedly; When the channel adjusting module 500 drives the bellows 310 to stretch and retract, the elastic air curtain diaphragm 330 inside can synchronously and smoothly follow the stretching and retracting, and always maintain the effective sealing cover of the channel lower end port to the measuring mirror 130, so as to ensure the sealing and isolation effect of the air curtain.

[0023] Further, referring to Figure 5 and Figure 6 , for the axial stretching and retracting adjustment of the elastic air curtain diaphragm 330, the sealing sleeve 200 is provided with an annular sliding groove 340, the annular sliding groove 340 is slidably embedded with a sliding ring 350, and the annular sliding groove 340 is circumferentially provided with a plurality of traction springs 360 connected with the sliding ring 350; Specifically, the elastic air curtain diaphragm 330 itself has a certain elastic deformation performance, and at the same time the traction spring 360 can exert a pulling force on the sliding ring 350, so as to use the sliding ring 350 to pull the elastic air curtain diaphragm 330, so as to ensure that the elastic air curtain diaphragm 330 can always keep straight; when the bellows 310 is stretched, the elastic air curtain diaphragm 330 can be self-adapted to stretch, and at the same time the sliding ring 350 can slide downward in the annular sliding groove 340 by a distance, so as to compensate the stretching amount of the elastic air curtain diaphragm 330, to avoid the elastic air curtain diaphragm 330 from being broken due to exceeding the elastic limit.

[0024] It should be noted that the traction spring 360 continuously exerts an axial traction force on the elastic air curtain diaphragm 330 through the sliding ring 350, effectively overcoming the influence of gravity or deformation relaxation, so as to ensure that the elastic air curtain diaphragm 330 always keeps straight at any length, thereby maintaining the straight extension of the internal air curtain channel, and ensuring the accuracy of the light beam propagation path; When the bellows 310 is stretched under the driving of the channel adjusting module 500, the elastic air curtain diaphragm 330 is self-adapted to stretch, and at the same time the sliding ring 350 slides downward along the annular sliding groove 340 under the action of the traction spring 360, and this sliding action compensates the additional length required by the elastic air curtain diaphragm 330, so as to avoid the elastic air curtain diaphragm 330 from being broken or permanently deformed due to the stretching amount exceeding the elastic limit, thereby improving the structural reliability and service life; The sliding of the sliding ring 350 in the annular sliding groove 340 and the stretching and retracting characteristics of the traction spring 360 make the structure dynamically adapt to the length change of the bellows 310; during the adjustment process, the deformation amount is automatically compensated, and the straightness and integrity of the elastic air curtain diaphragm 330 can be maintained without additional control.

[0025] Further, please refer to Figure 5 and Figure 7 In order to make the gas curtain atmosphere completely cover the peripheral space of the measuring mirror 130, the lower end of the bellows 310 is provided with a conical shell 320, and the inner side of the conical shell 320 is provided with a fairing 390; Specifically, by wrapping the measuring mirror 130 with the conical shell 320, the fairing 390 guides the airflow inward, so that the airflow in the gas curtain passage flows from top to bottom through the fairing 390. In this way, when the processing module 800 is displaced in the horizontal range, the conical shell 320 can always cover the reflection range of the measuring mirror 130, and the gas curtain atmosphere is always wrapped above the measuring mirror 130, so as to maintain the temperature of the laser propagation path.

[0026] It should be noted that the conical shell 320 is arranged at the lower end of the bellows 310, and the conical structure can always wrap and cover the measuring mirror 130 when the processing module 800 is horizontally displaced, so as to ensure that the reflection area of the measuring mirror 130 is always within the protection range of the gas curtain, avoiding the invalidation of the gas curtain protection due to the movement of the equipment; The fairing 390 is located inside the conical shell 320, and forcibly guides the inert gas airflow in the gas curtain passage inward and downward to form a directional laminar flow wrapping the measuring mirror 130, so as to tightly cover the gas curtain atmosphere above and around the measuring mirror 130, and effectively isolate external interference; The directional airflow continuously wraps the measuring mirror 130, forming a gas environment with uniform temperature and no disturbance on the surface of the mirror, significantly reducing the thermal gradient and air turbulence, and ensuring the stability of the reflection path and the consistency of the optical path of the laser beam at the measuring mirror 130.

[0027] In another embodiment, please refer to Figure 5 and Figure 6 The gas curtain construction module 400 includes a gas cavity 410 opened in the sealing sleeve 200, a plurality of gas injection ports 420 are circumferentially arranged on the inner side of the gas cavity 410 and communicated with the gas curtain passage, and a gas pipe 430 is communicated with the outer side of the gas cavity 410; Specifically, the inert gas is continuously introduced into the gas cavity 410 through the gas pipe 430, and the gas is uniformly injected into the gas curtain passage through the circumferential gas injection ports 420, so as to form a laminar stable gas curtain atmosphere in the gas curtain passage; The gas cavity 410 serves as a gas distribution chamber, and the inert gas is injected into the gas curtain passage through the circumferentially uniformly distributed gas injection ports 420. The annular array type gas supply ensures that the inert gas is uniformly and synchronously injected along the entire circumferential direction of the passage, so as to form a uniform, symmetrical and stable laminar gas curtain atmosphere in the gas curtain passage; The uniform injected air flow is more likely to form a stable and low-turbulence laminar flow state in the straight air curtain channel, which can effectively suppress the disturbance and vortex flow inside the gas, and provide a highly consistent and low-interference gas medium environment for the laser measurement beam (from the laser head 120 to the measurement mirror 130 and back), thereby minimizing the beam jitter and optical path error; The air cavity 410 is directly arranged inside the sealing sleeve 200, the air outlet 420 is located inside the air cavity 410 and communicates with the air curtain channel, and the air pipe 430 is connected to the outside of the air cavity 410. The integrated structure makes the gas supply system have better sealing performance, reduces the risk of leakage, and ensures the directness and efficiency of the gas supply path.

[0028] Further, referring to Figure 4 , the channel adjusting module 500 includes a mounting sleeve 530 arranged on the mounting plate 110 and a bearing seat 510 arranged on the conical shell 320. The bearing seat 510 is rotatably installed with a threaded rod 520, the threaded rod 520 is threaded through the mounting sleeve 530, and the upper end of the threaded rod 520 is provided with a crank 540. Specifically, by rotating the threaded rod 520 relative to the bearing seat 510 through the crank 540, the threaded rod 520 can be threaded in the mounting sleeve 530, so that the conical shell 320 at the lower end is driven by the threaded rod 520 to move up and down, so as to flexibly adjust the contraction state of the bellows 310 according to the distance between the laser head 120 and the measurement mirror 130.

[0029] By rotating the threaded rod 520 in the bearing seat 510 through the crank 540, the threaded rod 520 is screwed with the mounting sleeve 530 to convert the rotary motion into precise linear displacement, so as to flexibly control the lifting of the conical shell 320 and the bellows 310, thereby accurately adjusting the extension length of the air curtain channel according to the actual distance between the laser head 120 and the measurement mirror 130. The threaded rod 520 is stably supported on the conical shell 320 through the bearing seat 510, and the mounting sleeve 530 is fixed to the mounting plate 110, forming a rigid transmission and support structure. The threaded transmission itself has a self-locking feature, which can automatically maintain the position after adjustment, prevent the air curtain channel from accidentally expanding or contracting due to vibration or gravity, adapt to different sizes of workpieces 900 or changes in measurement point positions, and ensure that the lower end of the conical shell 320 is always effectively covered on the measurement mirror 130, maintaining the air curtain sealing and ensuring the stability of the channel shape during the measurement process.

[0030] Further, referring to Figure 4 , Figure 5 and Figure 6, the humidity change of the processing environment is easy to cause the condensation of the water in the elastic air curtain diaphragm 330 inner wall to produce dew, and the size and position of the dew are relatively random, thereby affecting the propagation consistency of the air curtain atmosphere in the air curtain channel to the laser path; Therefore, it also includes an anti-dew module 600, the anti-dew module 600 includes a driving motor 610 fixed on the mounting plate 110 and a tooth ring 630 rotatingly embedded in the sealing sleeve 200, the driving motor 610 is provided with a gear 620 engaged with the tooth ring 630 at the output end, the lower end of the tooth ring 630 is fixed with a wiper 650 through a connecting frame 640, and the wiper 650 is attached to the inner wall of the elastic air curtain diaphragm 330; Specifically, when the dew is generated on the inner wall of the elastic air curtain diaphragm 330, the driving motor 610 drives the gear 620 to rotate, and under the meshing transmission of the gear 620 and the tooth ring 630, the tooth ring 630 and the connecting frame 640 are driven to rotate synchronously, thereby driving the wiper 650 to move circumferentially along the inner wall of the elastic air curtain diaphragm 330, so as to scrape off the dew attached to the inner wall of the elastic air curtain diaphragm 330, and keep the air curtain atmosphere inside the elastic air curtain diaphragm 330 consistent.

[0031] It should be noted that the wiper 650 closely attaches to the inner wall of the elastic air curtain diaphragm 330, and under the driving of the driving motor 610 through the meshing transmission of the gear 620 and the tooth ring 630, the wiper 650 moves circumferentially along the inner wall, effectively scraping off the dew droplets randomly formed on the inner wall due to the change of temperature and humidity, preventing the dew droplets from changing the local gas density or refractive index, and ensuring that the optical properties of the gas atmosphere in the air curtain channel are highly uniform; By timely removing the dew on the inner wall of the elastic air curtain diaphragm 330, the risk of local light path scattering, refraction anomaly or beam distortion caused by random attachment of dew droplets is eliminated, and the stability and optical path consistency of the laser measurement beam (from the laser head 120 to the measurement mirror 130 and back) in the air curtain channel are ensured.

[0032] Correspondingly, please refer to Figure 5 and Figure 7 , considering that after the wiper 650 scrapes off the dew on the inner wall of the elastic air curtain diaphragm 330, in order to avoid the dew falling on the lower measurement mirror 130 affecting the precision of laser interferometric measurement, the inner side of the conical cover 320 is provided with an annular drainage plate 370 matched with the elastic air curtain diaphragm 330, a drainage groove is formed between the annular drainage plate 370 and the elastic air curtain diaphragm 330, and a drainage flow channel 380 is formed in the conical cover 320 and communicates with the bottom of the drainage groove; Specifically, when the wiper 650 scrapes off the dew on the inner wall of the elastic air curtain diaphragm 330, the dew falls into the drainage groove between the annular drainage plate 370 and the elastic air curtain diaphragm 330 under the action of gravity, and then the accumulated water is discharged through the drainage flow channel 380, avoiding the direct contact of the accumulated water with the measurement mirror 130.

[0033] The drainage groove formed between the annular guide plate 370 and the elastic air curtain diaphragm 330 precisely catches condensation droplets scraped from the inner wall of the elastic air curtain diaphragm 330 by the scraper blade 650. This design effectively prevents condensation from dripping directly onto the surface of the measuring reflector 130 below, preventing water stains from contaminating the reflective surface or forming an uneven liquid film, thereby ensuring the optical cleanliness and reflection accuracy of the measuring reflector 130.

[0034] The bottom of the drainage trough is connected to the drainage channel 380 provided in the conical cover 320. The collected condensation water is automatically discharged from the system along the drainage channel 380 under the action of gravity, thereby preventing the accumulation of water at the bottom of the channel and eliminating the possibility of secondary interference with the measuring reflector 130 or the laser optical path due to shaking, evaporation or accidental splashing of the accumulated water. By quickly removing the scraped condensation, the interior of the air curtain channel (especially the key area near the measuring reflector 130) is ensured to remain dry for a long time, maintaining the purity and stability of the inert gas atmosphere. The laser measurement beam is not affected by the refractive index mutation or scattering caused by liquid water on the path to / from the measuring reflector 130, ensuring the consistency of the optical path.

[0035] In further embodiments, see Figure 8 and Figure 9 The tooling module 700 includes a magnetic plate 710 for magnetically fixing the lower end surface of the workpiece 900, and an inner support component 720 for radially expanding and fixing the inner wall of the workpiece 900 is provided on the magnetic plate 710; Further, see Figure 9 and Figure 10 The inner support assembly 720 includes a clamping cylinder 721 installed in the magnetic plate 710 and a plurality of inner support plates 723 circumferentially distributed around the clamping cylinder 721. A lifting platform 722 is installed at the output end of the clamping cylinder 721. A connecting rod 724 is hinged between the lifting platform 722 and each inner support plate 723. Specifically, the workpiece 900 is placed on the magnetic plate 710, and the workpiece 900 is magnetically fixed by the magnetic plate 710 to prevent the workpiece 900 from axial movement. The lifting platform 722 is then driven downward by the clamping cylinder 721. Under the transmission of the connecting rod 724, each inner support plate 723 is driven to expand radially outward, and the inner wall of the workpiece 900 in the inner support plate 723 is used to provide radial support to prevent the workpiece 900 from radial displacement.

[0036] It should be noted that the strong magnetic attraction force is applied to the lower end surface of the workpiece 900 by the magnetic attraction plate 710, effectively preventing the axial movement or disengagement of the workpiece 900 during machining; the inner support plate 723 is driven by the inner support assembly 720 to expand radially outward, tightly supporting the inner wall of the workpiece 900, eliminating the radial deviation or vibration of the workpiece 900 caused by machining stress; The magnetic attraction fixing does not require complex alignment, and the workpiece 900 is placed to achieve preliminary fixing, simplifying the operation process; the clamping cylinder 721 drives the lifting platform 722 to descend, and through the synchronous transmission of multiple groups of symmetrical connecting rods 724, the circumferentially distributed inner support plates 723 are synchronously and uniformly expanded radially, ensuring that the workpiece 900 is balanced in stress, avoiding local deformation or clamping stress concentration.

[0037] Further, please refer to Figure 1 , Figure 2 and Figure 8 , the machining module 800 includes a horizontal moving part 810, a vertical moving part 820, a lifting part 830 and a machining part 840, the horizontal moving part 810 includes a horizontal moving guide rod 811 fixed horizontally on the tooling module 700 and a horizontal moving slider 812 slidingly sleeved on the horizontal moving guide rod 811, one end of the horizontal moving guide rod 811 is provided with a horizontal moving motor 813, and the output end of the horizontal moving motor 813 is connected with a horizontal moving screw rod 814 threaded through the horizontal moving slider 812; The vertical moving part 820 includes a vertical moving guide rod 821 fixed vertically on the horizontal moving slider 812 and a vertical moving slider 822 slidingly sleeved on the vertical moving guide rod 821, one end of the vertical moving guide rod 821 is provided with a vertical moving motor 823, and the output end of the vertical moving motor 823 is connected with a vertical moving screw rod 824 threaded through the vertical moving slider 822; The lifting part 830 includes a lifting guide rod 831 fixed vertically on the vertical moving slider 822 and a lifting slider 832 slidingly installed on the lifting guide rod 831, one end of the lifting guide rod 831 is provided with a lifting motor 833, and the output end of the lifting motor 833 is connected with a lifting screw rod 834 threaded through the lifting slider 832; The machining part 840 includes a machining motor 841 installed on the lifting slider 832, and a milling disc 842 is detachably installed at the lower end of the machining motor 841; Specifically, through the three-axis independent driving and rigid guidance of the horizontal moving part 810, the vertical moving part 820 and the lifting part 830, the precise displacement of the machining part 840 in X / Y / Z three dimensions is realized, so as to perform milling machining on the upper end surface of the workpiece 900.

[0038] The specific embodiments of the present application are described above, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are merely illustrative, but not restrictive, and those skilled in the art can make many forms under the inspiration of the present application, which all belong to the protection of the present application.

Claims

1. A length measuring device based on laser interference, applied to a machining unit, wherein the machining unit comprises a tooling module (700) for clamping a workpiece (900) and a machining module (800) for machining the workpiece (900); characterized in that: The length measuring device comprises: A laser measurement module (100) comprising a mounting plate (110) disposed on a processing module (800) and a measurement reflector (130) attached to a workpiece (900), wherein a laser head (120) adapted to the measurement reflector (130) is mounted on the mounting plate (110), and a reference measurement mirror is built into the laser head (120); A sealing sleeve (200), wherein the sealing sleeve is arranged outside the laser head (120); An air curtain channel module (300) is provided on the sealing sleeve (200) and is used to form an air curtain channel between the laser head (120) and the measuring reflector (130); An air curtain construction module (400), which is arranged on the sealing sleeve (200) and is used to construct an air curtain atmosphere in the air curtain channel; The channel adjustment module (500) is arranged outside the air curtain channel module (300) and is used to adjust the length of the air curtain channel.

2. The length measuring device based on laser interferometry according to claim 1, characterized in that: The air curtain channel module (300) includes a bellows (310) installed on the lower end surface of the sealing sleeve (200) and an elastic air curtain diaphragm (330) coaxially distributed in the bellows (310), wherein the upper end of the elastic air curtain diaphragm (330) is telescopically arranged in the sealing sleeve (200), and the lower end of the elastic air curtain diaphragm (330) is fixedly connected to the lower end of the bellows (310).

3. The length measuring device based on laser interferometry according to claim 2, characterized in that: An annular sliding groove (340) is provided in the sealing sleeve (200), a slip ring (350) is slidably embedded in the annular sliding groove (340), and a plurality of traction springs (360) connected to the slip ring (350) are circumferentially arranged in the annular sliding groove (340).

4. The length measuring device based on laser interferometry according to claim 2, characterized in that: A conical cover (320) is provided at the lower end of the bellows (310), and a flow guide cover (390) is provided inside the conical cover (320).

5. The length measuring device based on laser interferometry according to claim 1, characterized in that: The air curtain construction module (400) includes an air cavity (410) opened in the sealing sleeve (200), a plurality of air jets (420) connected to the air curtain channel are opened circumferentially on the inner side of the air cavity (410), and an air pipe (430) is connected to the outer side of the air cavity (410).

6. The length measuring device based on laser interferometry according to claim 4, characterized in that: The channel adjustment module (500) includes a mounting sleeve (530) arranged on the mounting plate (110) and a bearing seat (510) arranged on the conical cover (320). A threaded rod (520) is rotatably mounted in the bearing seat (510). The threaded rod (520) is threadedly passed through the mounting sleeve (530). A crank (540) is provided at the upper end of the threaded rod (520).

7. The length measuring device based on laser interferometry according to claim 4, characterized in that: The invention also includes an anti-condensation module (600), wherein the anti-condensation module (600) includes a driving motor (610) fixed on the mounting plate (110) and a gear ring (630) rotatably embedded in the sealing sleeve (200), wherein the output end of the driving motor (610) is provided with a gear (620) meshing with the gear ring (630), and a scraper (650) is fixed to the lower end of the gear ring (630) via a connecting frame (640), and the scraper (650) is in contact with the inner wall of the elastic air curtain diaphragm (330).

8. The length measuring device based on laser interferometry according to claim 7, characterized in that: An annular drainage plate (370) adapted to the elastic air curtain diaphragm (330) is provided inside the conical housing (320), a drainage groove is formed between the annular drainage plate (370) and the elastic air curtain diaphragm (330), and a drainage channel (380) connected to the bottom of the drainage groove is provided inside the conical housing (320).

9. The length measuring device based on laser interferometry according to claim 1, characterized in that: The tooling module (700) comprises a magnetic plate (710) for magnetically fixing the lower end surface of the workpiece (900), and an inner support component (720) for radially expanding and fixing the inner wall of the workpiece (900) is provided on the magnetic plate (710).

10. The length measuring device based on laser interferometry according to claim 9, characterized in that: The inner support assembly (720) includes a clamping cylinder (721) installed in the magnetic plate (710) and a plurality of groups of inner support plates (723) circumferentially distributed around the clamping cylinder (721). A lifting platform (722) is installed at the output end of the clamping cylinder (721). Connecting rods (724) are hinged between the lifting platform (722) and each inner support plate (723).

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