High-rigidity turning and milling composite power tool spindle structure

Abstract

The invention belongs to the field of numerical control machine tool power spindles, and discloses a high-rigidity turning and milling composite power tool spindle structure. The high-rigidity turning and milling composite power tool spindle structure adopts a CAPTO standard tool interface, can realize high-rigidity connection of a tool and a spindle, and is very suitable for two working modes of turning and milling. The state monitoring method for the spindle structure of the high-rigidity turning and milling hybrid power tool comprises two parts: the distance measuring sensor is used for measuring the non-contact axial position change of the mechanical labyrinth flange plate rotating together with the spindle; the axial thermal displacement of the distance measuring sensor installation part is measured through a contact type displacement sensor and a thermal extension detection rod. The real-time monitoring of the thermal elongation of the main shaft, the running state of the bearing, the cutting vibration and the accidental collision is realized by embedding a plurality of sensors.

Description

Technical Field

[0001] This invention belongs to the field of CNC machine tool power spindles and relates to a high-rigidity turning and milling composite power tool spindle structure. Background Technology

[0002] Milling-turning machining is one of the development directions of high-end CNC machine tools. Horizontal milling-turning machining centers with slant beds and inclined Y-axis structures have become the mainstream for medium-to-large-sized heavy-duty horizontal milling-turning machining due to their excellent structural rigidity and small footprint. The tool spindle is the core component of the machine tool, and its comprehensive performance requirements are extremely high. In addition to complete milling spindle functions, when switching to turning processes, the tool spindle must achieve rigid locking to ensure that the tool tip does not abruptly change under cutting force, achieving good surface quality and dimensional accuracy of the workpiece. The conical tool holder interface commonly used in existing tool spindles cannot fully meet these requirements in principle. During spindle operation, thermal expansion occurs due to localized temperature rise in the bearings, leading to changes in machining dimensions. Furthermore, vibration of the tool spindle due to changes in cutting force during milling also affects machining accuracy. Existing composite machining tool spindles also lack comprehensive monitoring functions. Therefore, milling-turning machine tool manufacturers have been continuously improving the rigidity and intelligence of tool spindles. Li Xiankai's paper, "Key Technologies of Five-Spindle Heads in Turning-Milling Composite Machines," also mentions that the position of the three-tooth disc mechanism in a five-spindle turning-milling head has a significant impact on machining performance; how to prevent the spindle bearing from being impacted during tool release is a challenge for five-spindle turning-milling heads. This invention addresses these problems through structural innovations such as a completely new spindle bearing and locking tooth disc layout, and the embedding of multiple sensors. It can meet all the requirements of both turning and milling processes for the tool-driven spindle, and features high rigidity, comprehensive digital detection and monitoring. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention proposes a novel spindle bearing layout structure that uses a CAPTO standard tool interface, enabling a high-rigidity connection between the tool and the spindle, making it ideal for both turning and milling operations. The front bearing employs a double-row cylindrical roller bearing, while the rear bearing uses a three-row angular contact ball bearing. The three-tooth disc for spindle locking is located near the rear bearing, and a flexible sleeve for auxiliary spindle locking is also designed at the front end of the spindle. This is a rear-end positioned spindle support structure. The front bearing uses a double-row cylindrical roller bearing, and the spindle locking three-tooth disc is arranged at the rear end. This layout gives the front bearing very high radial stiffness, and the front bearing support position is as close as possible to the tool's point of action, ensuring that the spindle can complete milling work with high performance. There is also an auxiliary locking flexible sleeve at the front end of the spindle. The locking three-tooth disc is arranged together with the ball bearing at the rear end, which has slightly weaker radial stiffness. This minimizes over-positioning interference between the locking three-tooth disc and the support bearing, which is beneficial for high-rigidity locking of the spindle during turning operations. The three-tooth disc mechanism also has a positioning base surface, which can reduce the impact of the tool release piston on the spindle bearing during tool changes.

[0004] A high-rigidity milling and turning composite power tool spindle structure includes a spindle extension mechanism comprising two parts: a distance sensor for non-contact measurement of the axial position variation of a mechanical labyrinth flange rotating with the spindle; and a contact displacement sensor and a thermal expansion detection rod for measuring the axial thermal displacement of the parts mounted on the distance sensor. This monitoring method takes into account the local thermal deformation of parts such as the spindle housing caused by the temperature rise of the bearing outer ring and the thermal expansion of the spindle spindle caused by the temperature rise of the bearing inner ring. The combined measurement data from these two parts can directly reflect the thermal expansion between the spindle tool interface and the spindle housing swing centerline. Other status monitoring methods include: two radial distance sensors arranged at the front end of the spindle to monitor the radial runout of the mechanical labyrinth flange in real time; continuous measurement of the tool release piston position through transmission mechanisms such as rocker arms and guide rods; real-time monitoring of the working status of the flexible sleeve and locking gear plate that complete the spindle locking using displacement sensors; and temperature sensors in direct contact with the outer rings of the front and rear bearings to monitor the bearing temperature rise.

[0005] The technical solution of the present invention:

[0006] A high-rigidity milling and turning composite power tool spindle structure includes the following structure:

[0007] The spindle housing is a cuboid with mounting flanges on its upper and lower planes. The rotation center line of the mounting flange is the spindle swing center line. The mounting flange is used to connect with the machine tool swivel head and to exchange electromechanical and hydraulic pipelines. The high-rigidity milling and turning composite power tool spindle structure can swing around the spindle swing center line to perform multi-angle machining on the workpiece.

[0008] The two ends of the spindle mandrel are respectively installed in the spindle housing via front support bearings and rear support bearings;

[0009] The front support bearing is a double-row cylindrical roller bearing with a 1:12 taper in the inner diameter direction. The axial position of the front support bearing on the spindle is determined by grinding the front bearing adjusting shim, so that the inner ring of the front support bearing expands to eliminate the initial clearance, thereby achieving the preload and radial stiffness designed for the front support bearing.

[0010] The rear support bearing consists of three sets of angular contact ball bearings. Two sets of angular contact ball bearings have the same contact angle direction, which together resists the axial component force of milling. The other set of angular contact ball bearings has the opposite contact angle direction. A bearing spacer is also arranged between the rear support bearing and the other two sets of angular contact ball bearings. The preload of the rear support bearing is adjusted by grinding the bearing spacer. The outer ring of the rear support bearing is pressed into the mounting hole of the spindle housing by a fixed gear disc and a matching fixed gear disc adjusting shim. The inner ring of the rear support bearing is fixed to the spindle mandrel by a rotating gear disc and matching rotating gear disc adjusting shims and an axial locking adjusting shim. The spindle mandrel is axially positioned by the rear support bearing.

[0011] Both the mechanical labyrinth flange and the tool interface flange are mounted on the front end of the spindle mandrel;

[0012] The locking gear, the rear cylinder of the spindle, and the sealing end cover constitute the hydraulic oil chamber for locking and releasing the three-gear mechanism. The three-gear mechanism mainly consists of a fixed gear, a rotating gear, and a locking gear. The rear cylinder of the spindle is mounted on the end face of the fixed gear. The sealing end cover is pressed against the inner end face of the rear cylinder by the rear cylinder cover. The locking gear is mounted inside the rear cylinder and can reciprocate under hydraulic pressure. The sealing end cover is mounted at the front end of the rear cylinder cover, and a guide cylindrical pin is fixed to the end face of the sealing end cover. The rear cylinder cover is mounted on the end face of the rear cylinder. The tool release piston is installed in the rear cylinder cover and forms a tool release oil chamber through a sealing element.

[0013] The transmission bevel gear is mounted on the main spindle and driven by a flat key;

[0014] The tool draw mechanism is installed in the inner hole of the spindle mandrel, and the tool release flange is installed at the rear end of the tool draw mechanism;

[0015] Under hydraulic pressure, the tool release flange is pushed, and the tool is loaded into the broaching mechanism. After the hydraulic pressure is disconnected, the nitrogen spring inside the broaching mechanism drives the broaching claw at its front end to lock the tool onto the tool interface flange. The transmission bevel gear drives the spindle mandrel to rotate through the flat key, and the milling operation begins. After the spindle mandrel drives the rotating gear plate and the fixed gear plate to achieve angular positioning, the locking gear plate moves towards the rotating gear plate under the hydraulic pressure in the rear cylinder of the spindle. During the movement, it is guided by the guide cylindrical pin on the sealing end cover to prevent circumferential rotation. Under the action of the locking gear plate, the positioning base surfaces of the rotating gear plate and the fixed gear plate are in close contact, and the tooth surfaces of the fixed gear plate, the rotating gear plate and the locking gear plate are in complete contact. The three-gear plate mechanism completes the locking. The spindle mandrel is restricted from rotating by the rotating gear plate, and the high-rigidity milling and turning composite power tool spindle structure switches to the turning operation mode.

[0016] The front end of the spindle mandrel also has a flexible conical locking mechanism. The front locking cylinder is installed on the front face of the spindle housing, and the front sealing disc is installed on the end face of the front locking cylinder. The flexible locking sleeve moves back and forth in the front locking cylinder under the action of hydraulic oil. When the high-rigidity milling and turning composite power tool spindle structure switches to the turning working mode, the flexible conical locking mechanism starts to work. The locking conical surface of the flexible locking sleeve is closely fitted with the outer conical surface of the front of the spindle mandrel, and the radial force acting on the front end of the spindle mandrel is transmitted to the front locking cylinder. There are also six cuts evenly distributed along the circumference on the locking conical surface of the flexible locking sleeve.

[0017] The high-rigidity milling and turning composite power tool spindle structure monitors the tool release and pull-out process: a tool release displacement sensor continuously digitally measures the position of the tool release piston. Under the action of hydraulic oil, the front end of the tool release piston contacts the tool release flange, pushing the pull-out mechanism to complete the tool release action; a round-headed pin is tightened on the tool release piston; a rocker arm is installed inside the spindle rear cylinder head via a support shaft; one end of the rocker arm is in contact with the round-headed pin, and the gear at the other end of the rocker arm meshes with the rack at one end of the guide rod; the other end of the guide rod is equipped with an angular positioning pin, which moves in the guide groove of the sensor mounting block. On the side of the spindle housing, a cylindrical compression spring is mounted on the guide rod via a spring washer and a locking nut. The cylindrical compression spring applies spring force to the rocker arm through the meshing tooth surfaces, ensuring that the rocker arm and the round-headed pin remain in contact during the movement of the release piston. The movement of the release piston is converted into the displacement of the detection plate mounted on the guide rod. The detection plate is fixed to the guide rod by another locking nut. The detection plate contacts the spring-reset detection rod in the release displacement sensor. The release displacement sensor is mounted on the sensor mounting block. By measuring the movement of the guide rod, the continuous measurement of the release piston stroke is indirectly achieved.

[0018] In this high-rigidity turning-milling composite power tool spindle structure, the spindle mandrel's working mode is monitored: a locking gear plate measuring bend is installed on the locking gear plate, and the locking gear plate measuring bend is in contact with the spring-reset detection rod in the gear plate displacement sensor. When the locking gear plate moves in the rear cylinder of the spindle, the gear plate displacement sensor directly feeds back the position of the locking gear plate; a locking sleeve measuring bend is installed on the flexible locking sleeve, and the locking sleeve measuring bend is in contact with the spring-reset detection rod in the locking sleeve displacement sensor. When the flexible locking sleeve moves in the front locking cylinder, the locking sleeve displacement sensor directly feeds back the position of the flexible locking sleeve. The spindle mandrel is monitored to be in turning or milling working mode through the gear plate displacement sensor and the locking sleeve displacement sensor.

[0019] In this high-rigidity milling and turning composite power tool spindle structure, the thermal expansion of the spindle mandrel is monitored: the front fixed end flange of the thermal expansion detection rod is pressed against the end face of the front locking cylinder by the front sealing disc. The rear moving end of the thermal expansion detection rod is flush with the spindle swing center line and is assisted by the support seat 46, which is installed on the side of the spindle housing. The outer circle of the thermal expansion detection rod slides in the inner hole of the front locking cylinder and the support seat. When the front sealing disc undergoes thermal displacement due to local temperature rise in the high-rigidity milling and turning composite power tool spindle structure, it also drives the thermal expansion detection rod to move together. The contact displacement sensor, which is in contact with the rear moving end of the thermal expansion detection rod, measures the distance change between the front sealing disc and the spindle swing center line. The probe of the contact displacement sensor is always in contact with the rear of the thermal expansion detection rod through the built-in return spring. The mobile end contacts a contact-type displacement sensor, which is locked in the support base. The axial distance sensor is fixed in the square groove of the front sealing plate through a sensor cover, which is installed on the end face of the front sealing plate. The eddy current probe inside the axial distance sensor directly measures the axial displacement of the mechanical labyrinth flange. The axial position of the mechanical labyrinth flange is the same as that of the tool interface flange. By monitoring the axial displacement of the mechanical labyrinth flange, the axial displacement change between the tool mounting end face on the tool interface flange and the front sealing plate is obtained. A labyrinth clearance adjustment shim is also provided between the spindle mandrel and the mounting surface of the mechanical labyrinth flange to adjust the distance between the axial distance sensor and the corresponding measuring surface on the mechanical labyrinth flange. The cable of the axial distance sensor passes through the wiring hole in the front locking cylinder and the thermal expansion detection rod.

[0020] The high-rigidity milling and turning composite power tool spindle structure monitors the vibration of the spindle mandrel: two radial distance sensors with a 90° circumferential gap are arranged in the front sealing plate. The radial distance sensors are pressed into the V-groove of the front sealing plate by sensor clamps, which are then fixed to the front sealing plate. When the spindle mandrel rotates, the eddy current probe inside the radial distance sensor measures the radial runout of the circumferential measuring surface on the mechanical labyrinth flange in real time. The measured value reflects the change in the spindle mandrel rotation accuracy. The measurement data from the two radial distance sensors and the axial distance sensor monitor the excessive displacement of the mechanical labyrinth flange caused by accidental tool collisions.

[0021] The high-rigidity milling and turning composite power tool spindle structure monitors the temperature rise of the front and rear support bearings: temperature sensor mounting holes are machined at the front and rear support bearings in the spindle housing. The front bearing temperature sensor is screwed into the temperature sensor mounting hole by its own thread, and its probe is in direct contact with the outer ring of the front support bearing; the rear bearing temperature sensor is screwed into the temperature sensor mounting hole by its own thread, and its probe is in direct contact with the outer ring of the angular contact ball bearing in the rear support bearing, thus monitoring the temperature change of the bearings in real time during spindle operation.

[0022] The beneficial effects of this invention are:

[0023] 1. This invention proposes a rear-end positioning bearing layout structure for a power tool spindle used in milling and turning composite machining. The bearings that bear radial support and axial positioning are arranged separately at the front and rear, and the preload is adjusted by grinding adjustment shims. This can simultaneously meet the requirements of high-rigidity milling and turning machining.

[0024] 2. The CAPTO standard structure is adopted as the tool interface form, which ensures high rigidity positioning of the tool tip during turning.

[0025] 3. In the critical actions of tool changing and spindle locking, the position information of the tool release piston, locking gear plate, and flexible locking sleeve are continuously monitored by displacement sensors and directly output as digital quantities, which improves the reliability of spindle operation.

[0026] 4. The spindle locking three-tooth disc is arranged at the rear end, which reduces the adverse effect of spindle thermal expansion on the locking rigidity of the tooth surface. A positioning base surface is added between the rotating tooth disc and the fixed tooth disc, eliminating the impact of the tool release force on the spindle bearing.

[0027] 5. A flexible locking sleeve is arranged at the front end of the spindle, with six empty tools evenly distributed along the circumference on the locking sleeve, which further improves the radial stiffness of the spindle during turning.

[0028] 6. By embedding multiple sensors, real-time monitoring of spindle thermal expansion, bearing operating status, cutting vibration, and accidental collisions is achieved. Attached Figure Description

[0029] Figure 1 This is the front view of a milling and turning spindle.

[0030] Figure 2 This is the rear view of a milling and turning spindle.

[0031] Figure 3 yes Figure 1 Sectional view AA of the milling and turning composite spindle.

[0032] Figure 4 yes Figure 3 Partial view of the milling spindle I of the CRRC.

[0033] Figure 5 yes Figure 2 BB section view of the milling compound spindle of the lap machine.

[0034] Figure 6 yes Figure 2 CC section view of the milling compound spindle of the CRRC.

[0035] Figure 7 yes Figure 1 DD section view of the milling and turning composite spindle of the lap machine.

[0036] Figure 8 yes Figure 1 Cross-sectional view of the milling and turning composite spindle FF (GG).

[0037] Figure 9 This is the left view of the milling and turning spindle.

[0038] Figure 10 yes Figure 9 Partial view of the milling spindle II of the CRRC.

[0039] In the diagram: 1. Spindle housing; 2. Spindle spindle; 3. Front support bearing; 4. Rear support bearing; 5. Mechanical labyrinth flange; 6. Tool interface flange; 7. Front bearing adjusting shim; 8. Broaching mechanism; 9. Bearing spacer; 10. Rotary gear disc adjusting shim; 11. Fixed gear disc adjusting shim; 12. Fixed gear disc; 13. Rotary gear disc; 14. Axial locking adjusting shim; 15. Locking gear disc; 16. Spindle rear cylinder; 17. Spindle rear cylinder cover; 18. Tool release piston; 19. Sealing end cover; 20. Tool release flange; 21. Drive bevel gear; 22. Flat key; 23. Flexible locking sleeve; 24. Front locking cylinder; 25. Front sealing disc; 26. Guide cylindrical pin; 27. Round head pin 28. Pin; 29. ​​Swing rod; 30. Support shaft; 31. Guide rod; 32. Cylindrical compression spring; 33. Washer; 34. Locking nut; 35. Angular positioning pin; 36. Detection plate; 37. Knife release displacement sensor; 38. Sensor mounting block; 49. Locking gear plate measuring bend; 40. Gear plate displacement sensor; 41. Locking sleeve displacement sensor; 42. Labyrinth clearance adjustment shim; 43. Axial distance sensor; 44. Sensor cover; 45. Thermal elongation detection rod; 46. Support base; 47. Contact displacement sensor; 48. Radial distance sensor; 49. Sensor pressure block; 50. Rear bearing temperature sensor; 51. Front bearing temperature sensor. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings and technical solutions.

[0041] The specific structure of a high-rigidity milling and turning composite power tool spindle is as follows:

[0042] Figure 1 , Figure 2 , Figure 9 This is an outline drawing of the high-rigidity milling and turning composite power tool spindle structure. The spindle housing 1 is a cuboid with mounting flanges on its upper and lower planes. The rotation center line of the mounting flange is the spindle swing center line. The mounting flange is used to connect with the machine tool swivel head and to exchange electromechanical and hydraulic pipelines. The high-rigidity milling and turning composite power tool spindle structure can swing around the spindle swing center line to perform multi-angle machining on the workpiece.

[0043] like Figure 3As shown, the two ends of the spindle mandrel 2 are respectively mounted in the spindle housing 1 via front support bearings 3 and rear support bearings 4. The front support bearing 3 is a double-row cylindrical roller bearing with a 1:12 taper in the inner diameter direction. The axial position of the front support bearing 3 on the spindle mandrel 2 is determined by grinding the front bearing adjusting shim 7, which causes the inner ring of the front support bearing 3 to expand to eliminate the initial clearance, thereby achieving the designed preload and radial stiffness of the front support bearing 3. The rear support bearing 4 consists of three sets of angular contact ball bearings, two of which have the same contact angle direction to jointly resist the milling axial force, and the other set of angular contact ball bearings has the same contact angle direction. The antennae are in opposite directions, and a bearing spacer 9 is arranged between the bearing and the other two sets of angular contact ball bearings. The preload of the rear support bearing 4 is adjusted by grinding the bearing spacer 9. The outer ring of the rear support bearing 4 is pressed into the mounting hole of the spindle housing 1 by the fixed gear plate 12 and the fixed gear plate adjusting shim 11 that cooperates with it. The inner ring of the rear support bearing 4 is fixed to the spindle mandrel 2 by the rotating gear plate 13 and the rotating gear plate adjusting shim 10 and the axial locking adjusting shim 14 that cooperate with it. The spindle mandrel 2 is axially positioned by the rear support bearing 4. The mechanical labyrinth flange 5 and the tool interface flange 6 are both installed at the front end of the spindle mandrel 2.

[0044] The locking gear 15, the spindle rear cylinder 16, and the sealing end cover 19 constitute the hydraulic oil chamber for locking and releasing the three-gear mechanism. The three-gear mechanism mainly consists of a fixed gear 12, a rotating gear 13, and a locking gear 15. The spindle rear cylinder 16 is mounted on the end face of the fixed gear 12. The sealing end cover 19 is pressed against the inner end face of the spindle rear cylinder 16 by the spindle rear cylinder cover 17. The locking gear 15 is installed inside the spindle rear cylinder 16 and can reciprocate under hydraulic pressure. The sealing end cover 19 is installed at the front end of the spindle rear cylinder cover 17, and a guide cylindrical pin 26 is fixed to the end face of the sealing end cover 19. The spindle rear cylinder cover 17 is installed on the end face of the spindle rear cylinder 16. The tool release piston 18 is installed in the spindle rear cylinder cover 17 and forms a tool release oil chamber through a sealing element.

[0045] The transmission bevel gear 21 is mounted on the main spindle 2 and is driven by the flat key 22;

[0046] The tool puller mechanism 8 is installed in the inner hole of the spindle spindle 2, and the tool release flange 20 is installed at the rear end of the tool puller mechanism 8;

[0047] Under hydraulic pressure, the tool release flange 20 is pushed, and the tool is loaded into the broaching mechanism 8. After the hydraulic pressure is disconnected, the nitrogen spring inside the broaching mechanism 8 drives the broaching claw at its front end to lock the tool onto the tool interface flange 6. The transmission bevel gear 21 drives the spindle spindle 2 to rotate through the flat key 22, and the milling operation begins. When the spindle spindle 2 drives the rotating gear disk 13 to achieve angular positioning with the fixed gear disk 12, the locking gear disk 15 moves towards the rotating gear disk 13 under the hydraulic pressure in the spindle rear cylinder 16. During the movement, it is guided by the guide cylindrical pin 26 on the sealing end cover 19 to prevent circumferential rotation. Under the action of the locking gear disk 15, the rotating gear disk 13 and the positioning base surface of the fixed gear disk 12 are in close contact, and the tooth surfaces of the fixed gear disk 12, the rotating gear disk 13 and the locking gear disk 15 are in complete contact. The three-gear mechanism completes the locking. The spindle spindle 2 is restricted from rotating by the rotating gear disk 13, and the high-rigidity milling and turning composite power tool spindle structure switches to the turning operation mode.

[0048] The front end of the spindle mandrel 2 also has a flexible conical locking mechanism. The front locking cylinder 24 is installed on the front end face of the spindle housing 1, and the front sealing disc 25 is installed on the end face of the front locking cylinder 24. The flexible locking sleeve 23 moves back and forth in the front locking cylinder 24 under the action of hydraulic oil. When the high-rigidity milling and turning composite power tool spindle structure switches to the turning working mode, the flexible conical locking mechanism starts to work. The locking conical surface of the flexible locking sleeve 23 is closely fitted with the outer conical surface at the front of the spindle mandrel 2, and the radial force acting on the front end of the spindle mandrel 2 is transmitted to the front locking cylinder 24. There are also six cuts evenly distributed along the circumferential direction on the locking conical surface of the flexible locking sleeve 23.

[0049] The spindle support bearing generates heat during high-speed rotation. This heat causes localized temperature rises in components such as the spindle mandrel 2 and spindle housing 1, resulting in changes in the axial distance between the tool interface flange 6 and the spindle swing centerline, affecting machining accuracy. Therefore, it is necessary to monitor the spindle's thermal expansion. (See also...) Figure 1 , Figure 7 , Figure 9 , Figure 10The specific implementation method is as follows: In this high-rigidity milling and turning composite power tool spindle structure, the thermal expansion of the spindle mandrel 2 is monitored. The front fixed end flange of the thermal expansion detection rod 45 is pressed against the end face of the front locking cylinder 24 by the front sealing disc 25. The rear moving end of the thermal expansion detection rod 45 is flush with the spindle swing center line and is supported by the support seat 46. The support seat 46 is installed on the side of the spindle housing 1. The outer circle of the thermal expansion detection rod 45 slides in the inner holes of the front locking cylinder 24 and the support seat 46. When the front sealing disc 25 experiences thermal displacement due to local temperature rise in the high-rigidity milling and turning composite power tool spindle structure, it also drives the thermal expansion detection rod 45 to move together. The contact displacement sensor 47, which is in contact with the rear moving end of the thermal expansion detection rod 45, measures the distance change between the front sealing disc 25 and the spindle swing center line. The probe of the contact displacement sensor 47 is always in contact with the thermal expansion detection rod 45 through a built-in return spring. The rear moving end contacts the contact displacement sensor 47, which is locked in the support base 46. The axial distance sensor 43 is fixed in the square groove of the front sealing plate 25 by the sensor cover 44, which is installed on the end face of the front sealing plate 25. The eddy current probe inside the axial distance sensor 43 directly measures the axial displacement of the mechanical labyrinth flange 5. The mechanical labyrinth flange 5 and the tool interface flange 6 are in the same axial position. By monitoring the axial displacement of the mechanical labyrinth flange 5, the axial displacement change between the tool mounting end face on the tool interface flange 6 and the front sealing plate 25 is obtained. A labyrinth clearance adjustment shim 42 is also provided between the mounting surface of the spindle mandrel 2 and the mechanical labyrinth flange 5 to adjust the distance between the axial distance sensor 43 and the corresponding measuring surface on the mechanical labyrinth flange 5. The cable of the axial distance sensor 43 passes through the wiring hole in the front locking cylinder 24 and the thermal elongation detection rod 45. When the spindle structure operates at high speed, the local temperature rise caused by the bearing heating causes the temperature field of parts such as the spindle housing 1 and spindle spindle 2 to change in real time. The axial position change of the tool interface flange 6 where the tool is installed can be monitored in real time through the above measurement results.

[0050] The spindle of the milling-turning composite power tool not only needs high-speed rotation for milling but also requires turning capabilities. Therefore, the spindle must be locked to ensure that the cutting force from the turning tool is transmitted to the spindle housing 1 without backlash. This involves two key locking mechanisms: first, the connection between the tool and the spindle mandrel 2, which uses the CAPTO standard connection method to achieve a backlash-free connection in the tool rotation direction; second, the high-rigidity locking between the spindle mandrel 2 and the spindle housing 1. This invention employs a three-tooth disk mechanism with a positioning base surface, positioned on one side of the fixed end of the spindle. This arrangement reduces the axial position change of the rotating tooth disk 13 caused by spindle thermal expansion and weakens over-positioning interference caused by misalignment with the spindle support bearing during locking. Both improvements enhance the locking rigidity of the three-tooth disk. The three-tooth disk mechanism in this invention also features a positioning base surface; the tooth surface machining of the rotating tooth disk 13 and the fixed tooth disk 12 is performed in groups using this positioning base surface as the process reference. See also... Figure 3 , Figure 4 The specific implementation method is as follows: First, grind the fixed gear plate adjustment shim 11 so that the fixed gear plate 12 can press against the outer ring of the spindle rear support bearing. Then, use screws to install the fixed gear plate adjustment shim 11 and the fixed gear plate 12 together on the rear end face of the spindle housing 1. Pay attention to the angular position of the fixed gear plate 12 during assembly. Then, grind the rotating gear plate adjustment shim 10 and the axial locking adjustment shim 14 so that the positioning base surface on the fixed gear plate 12 and the rotating gear plate 13 maintains a gap of 0.02-0.03mm during the milling working mode. Use screws to lock the rotating gear plate 13 and the axial locking adjustment shim 14 to the rear end face of the spindle mandrel 2. At the same time, the inner ring of the spindle rear support bearing is pre-tightened. The locking gear 15, together with the spindle rear cylinder 16 and the sealing end cover 19, forms a hydraulic oil chamber for locking and releasing the three-tooth disc. Under the action of hydraulic oil, the locking gear 15 moves within the spindle rear cylinder 16. During movement, it is guided by the guide pin 26 on the sealing end cover 19 to prevent tooth ejection during locking. When the three-tooth disc mechanism locks, the locking gear 15 moves and first contacts the tooth surface of the rotating gear 13, then continues to move towards the fixed gear 12 until the positioning base surfaces of the rotating gear 13 and the fixed gear 12 are completely pressed together. All degrees of freedom of the rotating gear 13 are restricted, and the locking force of the locking gear 15 is relatively evenly distributed across the tooth surfaces of the rotating gear 13 and the fixed gear 12. The overall locking rigidity of the three-tooth disc mechanism is very high. At this time, the impact force acting on the spindle spindle 2 during tool release is also resisted by the locked three-tooth disc mechanism, which is beneficial to maintaining the accuracy of the spindle support bearing.

[0051] To further improve the locking rigidity of the spindle in turning mode, an auxiliary locking mechanism is also provided at the front end of the spindle. See [link / reference needed]. Figure 3The implementation method involves machining a locking conical surface at the front of the spindle mandrel. The flexible locking sleeve 23 reciprocates within the front locking cylinder 24 under the action of hydraulic oil. The locking conical surface of the flexible locking sleeve 23 fits tightly against the outer conical surface at the front of the spindle mandrel 2. This allows the radial force acting on the spindle mandrel 2 to be transmitted to the inner hole of the front locking cylinder 24 through the locking conical surface of the flexible locking sleeve 23. Furthermore, since there is a coaxiality error between the aforementioned locking conical surface and the front support bearing 3 of the spindle, six slits are uniformly machined along the circumferential direction on the locking conical surface of the flexible locking sleeve 23 to improve the contact rate between the locking conical surfaces.

[0052] The high-rigidity milling and turning composite power tool spindle structure monitors the broaching process, and the relevant implementation methods are as follows:

[0053] The status of the pull-out process was monitored; see [link / reference]. Figure 5 , Figure 9 The position of the release piston 18 is continuously digitally measured by the release displacement sensor 36. Under the action of hydraulic oil, the front end of the release piston 18 contacts the release flange 20, pushing the puller mechanism 8 to complete the release action. The round-headed pin 27 is tightened on the release piston 18. The rocker arm 28 is installed inside the rear cylinder head 17 of the main spindle via the support shaft 29. One end of the rocker arm 28 is in contact with the round-headed pin 27, and the gear at the other end of the rocker arm 28 meshes with the rack at one end of the guide rod 30. The other end of the guide rod 30 is equipped with an angular positioning pin 34, which moves in the guide groove of the sensor mounting block 37. The sensor mounting block 37 is installed on the side of the main spindle housing 1. The cylindrical compression spring 31 passes through... A spring washer 32 and a locking nut 33 are installed on the guide rod 30. The cylindrical compression spring 31 applies spring force to the rocker arm 28 through the meshing tooth surface, so that the rocker arm 28 and the round-headed pin 27 remain in contact during the movement of the knife release piston 18. The movement position of the knife release piston 18 is converted into the displacement of the detection plate 35 installed on the guide rod 30. The detection plate 35 is fixed to the guide rod 30 by another locking nut 33. The detection plate 35 contacts the spring-reset detection rod in the knife release displacement sensor 36. The knife release displacement sensor 36 is installed on the sensor mounting block 37. By measuring the movement position of the guide rod 30, the continuous measurement of the stroke of the knife release piston 18 is indirectly achieved.

[0054] The high-rigidity milling and turning composite power tool spindle structure monitors the working mode of the spindle mandrel 2: See [link / reference] Figure 6The locking gear plate measuring bend 38 is installed on the locking gear plate 15. The locking gear plate measuring bend 38 is in contact with the spring-reset detection rod in the gear plate displacement sensor 39. When the locking gear plate 15 moves in the rear cylinder 16 of the spindle, the gear plate displacement sensor 39 directly feeds back the position of the locking gear plate 15. The locking sleeve measuring bend 41 is installed on the flexible locking sleeve 23. The locking sleeve measuring bend 41 is in contact with the spring-reset detection rod in the locking sleeve displacement sensor 40. When the flexible locking sleeve 23 moves in the front locking cylinder 24, the locking sleeve displacement sensor 40 directly feeds back the position of the flexible locking sleeve 23. The spindle mandrel 2 is monitored to be in turning or milling mode through the gear plate displacement sensor 39 and the locking sleeve displacement sensor 40.

[0055] In this high-rigidity milling and turning composite power tool spindle structure, vibration of the spindle mandrel 2 is monitored: See [link / reference needed] Figure 1 , Figure 8 Because the monitored object rotates at high speed, a non-contact ranging sensor is selected. Two radial ranging sensors 48 with a circumferential gap of 90° are arranged in the front sealing disc 25. The radial ranging sensors 48 are pressed into the V-groove of the front sealing disc 25 by sensor pressure blocks 49, and the sensor pressure blocks 49 are fastened to the front sealing disc 25. When the spindle spindle 2 rotates, the eddy current probe inside the radial ranging sensor 48 measures the radial runout of the circumferential measuring surface on the mechanical labyrinth flange 5 in real time. The measured value reflects the change in the rotational accuracy of the spindle spindle 2. The measurement data of the two radial ranging sensors 48 and the axial ranging sensor 43 monitor the excessive displacement of the mechanical labyrinth flange 5 caused by accidental collision of the tool.

[0056] In this high-rigidity milling and turning composite power tool spindle structure, the temperature rise of the front support bearing 3 and the rear support bearing 4 is monitored: See [link / reference needed] Figure 9 Temperature sensor mounting holes are machined at the front support bearing 3 and the rear support bearing 4 in the spindle housing 1. The front bearing temperature sensor 51 is screwed into the temperature sensor mounting hole by its own thread, and its probe is in direct contact with the outer ring of the front support bearing 3. The rear bearing temperature sensor 50 is screwed into the temperature sensor mounting hole by its own thread, and its probe is in direct contact with the outer ring of the angular contact ball bearing in the rear support bearing 4, so as to monitor the temperature change of the bearing in real time when the spindle is running.

Claims

1. A high-rigidity milling and turning composite power tool spindle structure, characterized in that, The high-rigidity milling and turning composite power tool spindle structure includes the following components: The spindle housing (1) is a cuboid with mounting flanges on its upper and lower planes. The rotation center line of the mounting flange is the spindle swing center line. The mounting flange is used to connect with the machine tool swing head and perform electromechanical and hydraulic pipeline interaction. The high rigidity milling and turning composite power tool spindle structure can swing around the spindle swing center line to perform multi-angle machining on the workpiece. The two ends of the spindle mandrel (2) are respectively installed in the spindle housing (1) through the front support bearing (3) and the rear support bearing (4); The front support bearing (3) is a double-row cylindrical roller bearing with a 1:12 taper in the inner diameter direction. The axial position of the front support bearing (3) on the main spindle (2) is determined by grinding the front bearing adjusting shim (7), so that the inner ring of the front support bearing (3) expands to eliminate the initial clearance, thereby realizing the preload and radial stiffness designed for the front support bearing (3). The rear support bearing (4) consists of three sets of angular contact ball bearings. Two sets of angular contact ball bearings have the same contact angle direction and jointly resist the axial component force of milling. The other set of angular contact ball bearings has the opposite contact angle direction and a bearing spacer (9) is arranged between it and the other two sets of angular contact ball bearings. The preload of the rear support bearing (4) is adjusted by grinding the bearing spacer (9). The outer ring of the rear support bearing (4) is pressed into the mounting hole of the spindle housing (1) by the fixed gear plate (12) and the fixed gear plate adjusting shim (11) that cooperates with it. The inner ring of the rear support bearing (4) is fixed to the spindle mandrel (2) by the rotating gear plate (13) and the rotating gear plate adjusting shim (10) and the axial locking adjusting shim (14) that cooperate with it. The spindle mandrel (2) is axially positioned by the rear support bearing (4). The mechanical labyrinth flange (5) and the tool interface flange (6) are both installed at the front end of the spindle mandrel (2); The locking gear plate (15), the spindle rear cylinder (16), and the sealing end cover (19) constitute the hydraulic oil chamber for locking and releasing the three-gear plate mechanism; the three-gear plate mechanism is mainly composed of a fixed gear plate (12), a rotating gear plate (13), and a locking gear plate (15); the spindle rear cylinder (16) is installed on the end face of the fixed gear plate (12), and the sealing end cover (19) is pressed against the inner end of the spindle rear cylinder (16) by the spindle rear cylinder cover (17). On the surface, the locking gear plate (15) is installed inside the rear cylinder of the main spindle (16) and can reciprocate under hydraulic pressure. The sealing end cover (19) is installed at the front end of the rear cylinder cover of the main spindle (17). The guide cylindrical pin (26) is fixed on the end face of the sealing end cover (19). The rear cylinder cover of the main spindle (17) is installed on the end face of the rear cylinder of the main spindle (16). The tool release piston (18) is installed in the rear cylinder cover of the main spindle (17) and forms a tool release oil chamber through the sealing element. The transmission bevel gear (21) is mounted on the main spindle (2) and driven by a flat key (22); The drawbar mechanism (8) is installed in the inner hole of the spindle mandrel (2), and the tool release flange (20) is installed at the rear end of the drawbar mechanism (8); Under hydraulic pressure, the tool release flange (20) is pushed, and the tool is loaded into the tool puller mechanism (8). After the hydraulic pressure is disconnected, the nitrogen spring inside the tool puller mechanism (8) drives the puller claw at its front end to lock the tool onto the tool interface flange (6). The transmission bevel gear (21) drives the spindle mandrel (2) to rotate through the flat key (22) to start the milling operation. When the spindle mandrel (2) drives the rotating gear disk (13) to achieve angular positioning with the fixed gear disk (12), the locking gear disk (15) rotates under the hydraulic pressure in the rear cylinder of the spindle. The gear plate (13) moves in the direction of the movement and is guided by the guide cylindrical pin (26) on the sealing end cover (19) to prevent circumferential rotation. Under the action of the locking gear plate (15), the rotating gear plate (13) is in close contact with the positioning base surface of the fixed gear plate (12), and the tooth surfaces of the fixed gear plate (12), the rotating gear plate (13) and the locking gear plate (15) are in complete contact. The three-gear plate mechanism completes the locking. The spindle core (2) is restricted from rotating by the rotating gear plate (13), and the high-rigidity milling and turning composite power tool spindle structure switches to the turning working mode. The front end of the spindle mandrel (2) also has a flexible conical locking mechanism. The front locking cylinder (24) is installed on the front end face of the spindle housing (1), and the front sealing disc (25) is installed on the end face of the front locking cylinder (24). The flexible locking sleeve (23) moves back and forth in the front locking cylinder (24) under the action of hydraulic oil. When the high rigidity milling and turning composite power tool spindle structure is switched to the turning working mode, the flexible conical locking mechanism starts to work. The locking conical surface of the flexible locking sleeve (23) is closely fitted with the outer conical surface of the front of the spindle mandrel (2), and the radial force acting on the front end of the spindle mandrel (2) is transmitted to the front locking cylinder (24). There are also six cuts evenly distributed along the circumferential direction on the locking conical surface of the flexible locking sleeve (23).

2. The high-rigidity milling and turning composite power tool spindle structure according to claim 1, characterized in that, In this high-rigidity milling and turning composite power tool spindle structure, the status monitoring of the tool release and pull-out process is performed: the position of the tool release piston (18) is continuously digitally measured by the tool release displacement sensor (36). Under the action of hydraulic oil, the front end face of the tool release piston (18) contacts the tool release flange (20), pushing the pull-out mechanism (8) to complete the tool release action; the round-headed pin (27) is tightened on the tool release piston (18), and the rocker arm (28) is installed inside the spindle rear cylinder head (17) through the support shaft (29). One end of the rocker arm (28) is in contact with the round-headed pin (27), and the gear at the other end of the rocker arm (28) meshes with the rack at one end of the guide rod (30). The other end of the guide rod (30) is equipped with an angular positioning pin (34), which moves in the guide groove of the sensor mounting block (37). The sensor mounting block (37) is installed on the spindle housing ( 1) Side view; The cylindrical compression spring (31) is installed on the guide rod (30) through the spring washer (32) and a locking nut (33). The cylindrical compression spring (31) applies the spring force to the rocker arm (28) through the meshing tooth surface, so that the rocker arm (28) and the round-headed pin (27) always keep in contact during the movement of the release piston (18). The moving position of the release piston (18) is converted into the displacement of the detection plate (35) installed on the guide rod (30). The detection plate (35) is fixed to the guide rod (30) through another locking nut (33). The detection plate (35) contacts the spring-reset detection rod in the release displacement sensor (36). The release displacement sensor (36) is installed on the sensor mounting block (37). By measuring the moving position of the guide rod (30), the continuous measurement of the stroke of the release piston (18) is indirectly realized.

3. The high-rigidity milling and turning composite power tool spindle structure according to claim 1, characterized in that, In this high-rigidity milling and turning composite power tool spindle structure, the working mode of the spindle mandrel (2) is monitored: the locking gear plate measuring bend (38) is installed on the locking gear plate (15), and the locking gear plate measuring bend (38) contacts the spring-reset detection rod in the gear plate displacement sensor (39). When the locking gear plate (15) moves in the spindle rear cylinder (16), the gear plate displacement sensor (39) directly feeds back the position of the locking gear plate (15); the locking sleeve measuring bend... (41) Installed on the flexible locking sleeve (23), the locking sleeve measuring plate (41) contacts the spring-reset detection rod in the locking sleeve displacement sensor (40). When the flexible locking sleeve (23) moves in the front locking cylinder (24), the locking sleeve displacement sensor (40) directly feeds back the position of the flexible locking sleeve (23). The spindle mandrel (2) is monitored to be in turning or milling working mode by the gear plate displacement sensor (39) and the locking sleeve displacement sensor (40).

4. The high-rigidity milling and turning composite power tool spindle structure according to claim 1, characterized in that, In this high-rigidity milling and turning composite power tool spindle structure, the thermal expansion of the spindle mandrel (2) is monitored: the front fixed end flange of the thermal expansion detection rod (45) is pressed against the end face of the front locking cylinder (24) by the front sealing disc (25), the rear moving end of the thermal expansion detection rod (45) is flush with the spindle swing center line and is assisted by the support seat (46), the support seat (46) is installed on the side of the spindle housing (1), and the outer circle of the thermal expansion detection rod (45) is between the front locking cylinder (24) and the support seat. (46) slides in the inner hole. When the front sealing disc (25) undergoes thermal displacement due to local temperature rise in the spindle structure of the high-rigidity milling and turning composite power tool, it also drives the thermal expansion detection rod (45) to move together. The contact displacement sensor (47), which is in contact with the rear moving end of the thermal expansion detection rod (45), measures the distance change between the front sealing disc (25) and the spindle swing center line. The probe of the contact displacement sensor (47) is always in contact with the rear moving end of the thermal expansion detection rod (45) through the built-in reset spring. The contact displacement sensor (47) is locked in the support base (46); the axial distance sensor (43) is fixed in the square groove of the front sealing plate (25) by the sensor cover (44), and the sensor cover (44) is installed on the end face of the front sealing plate (25); the eddy current probe inside the axial distance sensor (43) directly measures the axial displacement of the mechanical labyrinth flange (5), the axial position of the mechanical labyrinth flange (5) is the same as that of the tool interface flange (6), and the mechanical labyrinth flange (5) is monitored. The axial displacement change of the tool interface flange (6) is obtained to obtain the axial displacement change between the tool mounting end face on the tool interface flange (6) and the front sealing disc (25); a labyrinth gap adjustment shim (42) is also provided between the mounting surfaces of the spindle mandrel (2) and the mechanical labyrinth flange (5) to adjust the distance between the axial distance sensor (43) and the corresponding measuring surface on the mechanical labyrinth flange (5). The cable of the axial distance sensor (43) passes through the wiring hole in the front locking cylinder (24) and the thermal elongation detection rod (45).

5. The high-rigidity milling and turning composite power tool spindle structure according to claim 1, characterized in that, In this high-rigidity milling and turning composite power tool spindle structure, the vibration of the spindle mandrel (2) is monitored: two radial distance sensors (48) with a circumferential interval of 90° are arranged in the front sealing plate (25). The radial distance sensors (48) are pressed into the V-groove of the front sealing plate (25) by sensor pressure block (49), and the sensor pressure block (49) is fastened to the front sealing plate (25). When the spindle mandrel (2) rotates, the eddy current probe inside the radial distance sensor (48) measures the radial runout of the circumferential measuring surface on the mechanical labyrinth flange (5) in real time. The measured value reflects the change in the rotation accuracy of the spindle mandrel (2). The measurement data of the two radial distance sensors (48) and the axial distance sensor (43) monitor the excessive displacement of the mechanical labyrinth flange (5) caused by accidental collision of the tool.

6. The high-rigidity milling and turning composite power tool spindle structure according to claim 1, characterized in that, In this high-rigidity milling and turning composite power tool spindle structure, the temperature rise of the front support bearing (3) and the rear support bearing (4) is monitored: temperature sensor mounting holes are machined at the front support bearing (3) and the rear support bearing (4) in the spindle housing (1). The front bearing temperature sensor (51) is screwed into the temperature sensor mounting hole by its own thread, and its probe is in direct contact with the outer ring of the front support bearing (3); the rear bearing temperature sensor (50) is screwed into the temperature sensor mounting hole by its own thread, and its probe is in direct contact with the outer ring of the angular contact ball bearing in the rear support bearing (4), so as to monitor the temperature change of the bearing in real time when the spindle is running.

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