Turning mechanism for machining cylindrical thin-wall workpiece

Abstract

The invention discloses a turning mechanism for machining a cylindrical thin-wall workpiece, and belongs to the technical field of turning, the turning mechanism comprises a fixer for fixing the workpiece to turn an inner hole, the fixer is provided with a monitoring section at a weak part of the workpiece in the inner hole turning process, and the periphery of the workpiece is provided with a jacking piece capable of moving in the radial direction; and the friction power generation set is used for monitoring the radial outward movement of the jacking piece and reflecting the outward protruding state of the outer wall of the workpiece cylinder in the turning process, so that the turning back engagement is adjusted, and the turning quality is improved.

Description

Technical Field

[0001] This invention relates to the field of turning technology, and more specifically, to a turning mechanism for machining cylindrical thin-walled workpieces. Background Technology

[0002] Aircraft landing gear includes some thin-walled cylindrical parts with a high length-to-diameter ratio, which are typically machined using turning equipment. Some thin-walled parts require internal turning.

[0003] These types of parts have thin walls and a large length-to-diameter ratio, resulting in poor structural rigidity and making them highly susceptible to deformation in weak areas during machining. If the depth of cut is too large when machining weak areas, exceeding the workpiece's elastic buffer range, deformations such as outward bulging of the cylindrical wall and accumulation of wrinkles may occur. Therefore, it is necessary to monitor the condition of the workpiece's cylindrical wall during the turning process, promptly reduce the depth of cut if deformation is detected, and stop machining and discard the workpiece if the deformation is too large. Existing turning structures, such as the turning mechanism disclosed in patent document CN214349631U, use a cylindrical clamping mechanism that is fixedly fitted onto the outer wall of the workpiece to be turned. Only the outer walls of the workpiece at both ends are attached and fixed to the inner wall of the cylindrical structure, while the middle part (except for a very small portion of the outer wall in contact with a few circumferentially distributed pins) is suspended and not constrained by the contact between the cylindrical wall and the pins. That is, during the turning process, a large amount of the axial middle part of the workpiece is suspended and not constrained by the external mechanism, and its outer wall is completely surrounded and covered by the clamping mechanism, making it impossible to observe and judge the actual state of the cutting area of ​​the inner hole. If the depth of cut is too large when machining the weak points in this area of ​​the workpiece, the unconstrained and unobserved deformation of the workpiece cylinder wall will cause it to deform and bulge outwards. It will be difficult for personnel to detect and adjust the depth of cut in time to remedy the situation or to stop the workpiece and discard it. If the depth of cut is blindly reduced in order to avoid machining deformation, the machining efficiency will be significantly reduced.

[0004] Therefore, how to monitor the deformation and outward bulging state of the workpiece cylinder wall has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a turning mechanism for machining cylindrical thin-walled workpieces, so as to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A turning mechanism for machining cylindrical thin-walled workpieces includes a fixture for fixing the workpiece to turn an inner hole. The fixture includes a cylindrical fixing part and a triboelectric generator. The fixing part is fitted and sleeved on the outer wall of the workpiece. Along the axial direction of the fixing part, one end of the fixing part is fixed to the lathe spindle of the turning device. A monitoring section is provided in the middle, located at the weak point of the workpiece during the turning process. The inner cylindrical side of the monitoring section is provided with a first annular groove, and the outer cylindrical wall is provided with a radial guide hole. The workpiece, the cylindrical fixing part, the first annular groove and the lathe spindle are coaxial. The monitoring section is equipped with a triboelectric generator set of the triboelectric power generation device. The triboelectric generator set includes a first friction element and a second friction element, both mounted on a cylindrical fixing part and insulated from the workpiece and the cylindrical fixing part. The monitoring section also has two or more top supports, the number of which corresponds to the number of radial guide holes. Each top support includes a top support portion and a connecting portion. The top support portion is located within a first annular groove, with one side facing and fitting against the cylindrical outer wall of the workpiece. All top supports together cover the entire circumference of the workpiece corresponding to the monitoring section. One end of the connecting portion is fixed to the other side of the top support portion. The other end extends along the diameter direction corresponding to its corresponding radial guide hole, movably passing through the radial guide hole, and one end is fixed to the first friction member. In the triboelectric generator set, the first friction member and the second friction member are arranged opposite each other along the radial movement direction of the connecting part on the first friction member. When there is no external force, the first and second friction members of the triboelectric generator set are not in contact. The top support member is subjected to force and moves radially outward, causing the first friction member to deform and contact the second friction member, thus generating triboelectric power. The triboelectric generator set is also equipped with a detector for real-time monitoring and feedback of the triboelectric power generation status of its first and second friction members to the controller of the turning device. The controller adjusts the turning state accordingly.

[0007] Optionally, the detector is used to compare the peak voltage generated by the triboelectric generator with a first threshold and a second threshold. If the second threshold is less than the peak voltage generated by the triboelectric generator and less than the first threshold, the controller generates a control command to reduce the depth of cut. If the peak voltage generated by the triboelectric generator is greater than or equal to the first threshold, the controller generates a control command to stop processing.

[0008] Optionally, the workpiece is a workpiece with its outer diameter turned, and one axial end of the workpiece has an external thread. One axial end of the cylindrical fixing part is connected to the lathe spindle, and this end has an internal thread for connecting with the external thread at the axial end of the workpiece.

[0009] Optionally, the workpiece is a workpiece with its outer diameter turned. One axial end of the workpiece is away from the lathe spindle and has a connecting flange. The other axial end faces the lathe spindle and is installed on the lathe spindle by the retainer. The retainer also includes a reinforcing member. The reinforcing member is clamped and fixed to the annular convex wall of the connecting flange. The cylindrical outer wall of the cylindrical fixing part is provided with a reinforcing seat along the axial direction of the lathe spindle. There is a preset distance between the reinforcing seat and the reinforcing member. The reinforcing seat is located between the lathe spindle and the reinforcing member. The reinforcing member and the reinforcing seat are pre-tightly connected.

[0010] Optionally, the reinforcing member and the reinforcing seat are pre-tightened bolts.

[0011] Optionally, the workpiece is a workpiece with its outer diameter machined. One axial end of the workpiece has an axially extending protrusion forming a shoulder. The root of the protrusion has a second annular groove with the groove opening radially outward. The inner wall of the cylindrical fixing part has a third annular groove. The second and third annular grooves are arranged opposite to each other. The fixing device also includes a retaining spring. The retaining spring is sleeved in the second annular groove of the workpiece and passes through the third annular groove. The retaining spring is no longer squeezed by the cylindrical wall and naturally expands outward. The outer annular side of the retaining spring protrudes outward from the side wall of the workpiece and extends into the second annular groove, while the inner annular side is still in the third annular groove. An operating port is provided through the outer annular side of the third annular groove for operating the retaining spring to release its axial limitation.

[0012] Optionally, in the top support member, the contact area between the connecting part and the first friction member is smaller than the contact area between the top support member and the workpiece.

[0013] Optionally, the connecting part is a long rod, and the top support part is an arc-shaped plate for fitting against the outer wall of the workpiece. One rod-shaped end of the connecting part is fixed to the middle of the outer wall of the arc-shaped plate.

[0014] Optionally, the number of triboelectric generator sets in the triboelectric power generation device is the same as the number of monitoring sections and they are arranged one-to-one. The first and second friction components of the triboelectric generator set are both cylindrical. The first friction component is coaxially sleeved outside the monitoring section of the cylindrical fixed part and there is a first gap between the cylindrical walls. The second friction component is coaxially sleeved outside the first friction component and there is a second gap between the cylindrical walls. One end of the connecting part is fixed to the inner wall of the first friction element. When not subjected to external force, the first friction element is always cylindrical. The workpiece, the cylindrical fixing part, the first annular groove, the first friction element, the second friction element and the lathe spindle are coaxial. The top support is subjected to force and moves outward radially, causing the first friction element to deform and contact the second friction element, thus generating electricity through friction.

[0015] Optionally, at the monitoring section, the number of triboelectric generator sets is consistent with the number of top support members and is set in a one-to-one correspondence. Each triboelectric generator set includes a first cylindrical member and a second cylindrical member. The inner wall of the first cylindrical member has a friction layer as a first friction member, and the outer wall of the second cylindrical member has a friction layer as a second friction member. The axial directions of the first and second cylindrical members are consistent with the lathe spindle. The first cylindrical member is nested outside the second cylindrical member. The radial cross-section of the triboelectric generator set is always eccentrically nested, and the center of the eccentric circle is located on a first straight line. The first straight line of all radial cross-sections of the triboelectric generator set intersects perpendicularly with the lathe spindle axis. The axis of the first cylindrical member is close to the lathe spindle axis, and the axis of the second cylindrical member is far from the lathe spindle axis. When there is no external force, the first cylindrical member does not deform, the first friction member and the second friction member do not contact each other, and the triboelectric generator set does not generate electricity. When the top support member is subjected to force and moves radially outward, the first cylindrical member deforms, the first friction member contacts the second friction member, and triboelectric generation occurs.

[0016] Compared to existing technologies, this invention incorporates a monitoring section to monitor the deformation state of the outer wall of the cylinder during processing. The outer wall of the workpiece is completely surrounded and covered by the inner wall of the cylindrical fixing part and the top support part. The deformation of the outer wall of the workpiece is constrained and prevented by the frictional force of the contact surfaces of the cylindrical fixing part and the two adjacent top supports, the frictional force of the connecting part moving radially outward in the radial guide hole, and the elastic deformation capacity of the first friction element. If the depth of cut is within the normal range, the outer wall of the cylinder does not deform or expands slightly outward, the top support part does not move radially outward or is buffered and absorbed by the slight elastic deformation of the first friction element. The first friction element and the second friction element do not contact each other and do not generate electricity. At this time, the measuring instruments (ammeter, voltmeter, indicator light, buzzer, etc.) show normal readings, and processing can proceed normally. If the adjusted depth of cut is too large, the top support part moves outward, the elastic deformation of the first friction element is large, and it comes into contact with the second friction element to generate electricity through friction. This is monitored and fed back by the measuring instruments, which then reduce the depth of cut for remedial purposes or to stop the process and discard the workpiece. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the structure of a fixator provided in one embodiment of this application; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 for Figure 1 Radial cross-sectional view of the monitoring section in the embodiment; Figure 4 for Figure 3 A magnified view of a portion of the image; Figure 5 This is a schematic diagram of the structure of a fixator provided in one embodiment of this application; Figure 6 for Figure 5 Radial cross-sectional view of the monitoring section in the embodiment; Figure 7 for Figure 5 Radial cross-sectional view of the triboelectric generator in the embodiment; Figure 8 This is a radial cross-sectional view of a triboelectric generator according to an embodiment of this application; Figure 9 This is a radial cross-sectional view of a triboelectric generator according to an embodiment of this application.

[0018] Reference numerals: 100, cylindrical fixing part; 110, reinforcing seat; 120, first annular groove; 121, radial guide hole; 130, third annular groove; 140, internal thread; 151, first annular component; 152, circular annular pipe; 153, second annular component; 154, preload screw; 155, preload nut; 160, top support; 170, connecting part; 180, mounting seat; 210, first cylindrical component; 211, first friction component; 220, second friction component; 230, insulating layer; 300, snap ring; 400, workpiece; 410, second annular groove; 420, connecting flange. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] See Figures 1 to 9 As shown, this application provides a turning mechanism for machining a cylindrical thin-walled workpiece 400, including a fixture for fixing the workpiece 400 to turn an inner hole. The fixture includes a cylindrical fixing part 100 and a triboelectric generator. The fixing part is fitted and sleeved on the outer wall of the workpiece 400. Along the axial direction of the fixing part, one end of the fixing part is fixed to the lathe spindle of the turning device. A monitoring section is provided in the middle, located at the weak point of the workpiece 400 during the turning process. The inner side of the cylindrical section of the monitoring section is provided with a first annular groove 120, and the outer wall of the cylindrical section is provided with a radial guide hole 121. The workpiece 400, the cylindrical fixing part 100, the first annular groove 120 and the lathe spindle are coaxial. The monitoring section is equipped with a triboelectric generator set, which includes a first friction element 211 and a second friction element 220, both of which are installed on the cylindrical fixing part 100 and are insulated from the workpiece 400 and the cylindrical fixing part 100 at various points. The monitoring section is also equipped with two or more top supports. The number of top supports is the same as the radial guide holes 121, and they are set one-to-one. Each top support includes a top support part 160 and a connecting part 170. The top support part 160 is located in the first annular groove 120, with one side facing and fitting against the cylindrical outer wall of the workpiece 400. All the top supports 160 together cover the entire circumference of the workpiece 400 corresponding to the monitoring section. One end of the connecting part 170 is fixed to the other side of the top support part 160, and the other end of the connecting part 170 extends along the diameter direction corresponding to its corresponding radial guide hole 121, movably passing through the radial guide hole 121, and the end of the connecting part 170 is fixed to the first friction member 211. In the triboelectric generator, the first friction member 211 and the second friction member 220 are arranged opposite each other along the radial movement direction of the connecting part 170 on the first friction member 211. When there is no external force, the first and second friction members 220 of the triboelectric generator are not in contact, and the top support is subjected to force and moves radially outward (the outward movement direction is as follows). Figure 2 , 4 (As indicated by the arrow), the first friction element 211 deforms and contacts the second friction element 220, generating triboelectric power. The triboelectric power generation device is also equipped with measuring instruments for real-time monitoring and feedback of the triboelectric power generation status of the first and second friction elements 220. Preferably, the measuring instruments include a voltmeter, an ammeter, an indicator light, a buzzer, or other alarms. Taking the voltmeter and ammeter as examples, if the measured voltage and / or current values ​​are within the allowable range, normal turning is not required. If the measured voltage and / or current are greater than zero but lower than the first threshold, the outward convexity of the workpiece 400 is within the normal radial outward convexity of its elastic deformation. The depth of cut can be left unchanged or appropriately reduced (to 50%-80% of the original depth of cut). If the measured voltage and / or current exceeds the first threshold, the radial bulge of workpiece 400 exceeds the radial bulge limit of elastic deformation. This indicates excessive cutting depth, radial cutting force exceeding the material yield strength, plastic deformation of the entire wall thickness of the thin-walled cylinder, increased and permanent outer wall bulge, and no need to continue machining. Work should be stopped immediately, workpiece 400 disassembled, the cause analyzed, and the machining process for the next workpiece 400 adjusted. This application can also set a second threshold, 0 < second threshold < first threshold. If the second threshold is exceeded but the first threshold is not, workpiece 400 remains in an elastic deformation state but carries a certain risk. The threshold can be set based on the actual amount exceeded (second threshold); the greater the exceedance, the greater the reduction in cutting depth should be. If the exceedance is excessive (greater than the first threshold), work should be stopped, disassembled, the cause analyzed, and the machining process for the next workpiece 400 adjusted. This application does not specifically limit the alarm threshold of the measuring instrument; it can be flexibly set according to actual needs.

[0021] It should be noted that the wires of the first friction element 211 and the second friction element 220 in the triboelectric generator can be electrically connected to the stationary components of the triboelectric generator through an electric slip ring, which will not be elaborated in this application.

[0022] Compared to existing technologies, this invention incorporates a monitoring section to monitor the deformation state of the outer wall of the cylinder during processing. The outer wall of the workpiece 400 is fully surrounded and covered by the inner wall of the cylindrical fixing part 100 and the top support part 160. Deformation of the outer wall of the workpiece 400 is constrained by the frictional force of the cylindrical fixing part 100, the contact surfaces of adjacent top supports 160, the frictional force of the connecting part 170 moving radially outward in the radial guide hole 121, and the elastic deformation capability of the first friction element 211. If the depth of cut is within the normal range, and the outer wall of the cylinder does not deform or expands slightly outward, the top support does not move radially outward or is buffered and absorbed by the slight elastic deformation of the first friction element 211. The first friction element 211 and the second friction element 220 do not contact each other, and no electricity is generated. At this time, the measuring instruments (ammeter, voltmeter, indicator light, buzzer, etc.) display normal readings, and processing can proceed normally. If the depth of cut is adjusted too much, the support component will move outward, the first friction component 211 will have a large elastic deformation, and it will come into contact with the second friction component 220 to generate frictional electricity. This electricity will be monitored and fed back by the measuring instrument, and the depth of cut will be reduced accordingly to make remedial measures or to stop the operation and abandon the device.

[0023] Optionally, the controller of the turning mechanism is electrically connected to a measuring instrument, which is an ammeter and / or a voltmeter. The controller generates control commands based on the measured data to adjust the depth of cut.

[0024] In one possible implementation, such as Figure 7 As shown, the first and second friction elements 220 are fixed to the outer wall of the cylindrical fixing part 100 via the mounting base 180. The mounting base 180 is an annular protrusion on the outer wall of the cylindrical fixing part 100 and is an insulating component. The connection and fixing method between the cylindrical fixing part 100 and the lathe spindle is specifically limited. It can be fixed by clamping with a three-jaw chuck or by a detachable coupling, as long as it can be fixed coaxially to the lathe spindle.

[0025] In one possible implementation, the turning target is the emergency disconnect safety pin of the aircraft main landing gear disclosed in patent document CN118833386B. Optionally, the turning process includes a clamping mechanism for turning the outer diameter, which will not be elaborated here. The workpiece 400 to be machined into an inner hole is the workpiece 400 after its outer diameter is machined. One axial end of the workpiece 400 has an axially extending protrusion forming a shoulder. The root of the protrusion has a second annular groove 410 with the groove opening facing outward. The inner wall of the cylindrical fixing part 100 has a third annular groove 130. The second and third annular grooves 130 are arranged opposite to each other. The fixing device also includes a retaining spring 300. The retaining spring 300 is sleeved in the second annular groove 410 of the workpiece 400 and passes through the third annular groove 130. The retaining spring 300 is no longer squeezed by the cylindrical wall and naturally expands outward. The outer annular side of the retaining spring 300 protrudes outward from the side wall of the workpiece 400 and extends into the second annular groove 410. The inner annular side is still in the third annular groove 130. An operating port is provided through the outer annular side of the third annular groove 130 for operating the retaining spring 300 to release its axial limit.

[0026] Optionally, the workpiece 400 is the workpiece 400 after its outer diameter is turned. One axial end of the workpiece 400 has an external thread, and one axial end of the cylindrical fixing part 100 is connected to the lathe spindle. This end is provided with an internal thread 140 for connecting with the external thread at the axial end of the workpiece 400.

[0027] Optionally, the workpiece 400 is the workpiece 400 after its outer diameter has been turned. One axial end of the workpiece 400 is away from the lathe spindle and is provided with a connecting flange 420. The other axial end faces the lathe spindle and is installed on the lathe spindle by a retainer. The retainer also includes a reinforcing member, which is clamped and fixed to the annular convex wall of the connecting flange 420. The cylindrical outer wall of the cylindrical fixing part 100 is provided with a reinforcing seat 110. Along the axial direction of the lathe spindle, there is a preset distance between the reinforcing seat 110 and the reinforcing member. The reinforcing member and the reinforcing seat 110 are pre-tightened together. Optionally, the reinforcing member and the reinforcing seat 110 are pre-tightened together with bolts.

[0028] In one possible implementation, such as Figure 1As shown, the reinforcement includes a first annular component 151, a second annular component 153, a preload screw 154, and a preload nut 155. The first annular component 151 is circularly fitted onto the workpiece 400 whose inner bore is to be machined, and fits against the axial end of the connecting flange 420 facing the lathe spindle. An axially extending annular pipe 152 is connected to the outer edge of the first annular component 151. The annular pipe 152, the first annular component 151, and the second annular component 153 are all coaxial with the lathe spindle. One axial end of the second annular component 153 is flat and fits against the other axial end of the connecting flange 420 away from the lathe spindle. The first annular component 151 is located inside the annular pipe 152 and slides within it, with the sliding direction consistent with the lathe spindle axis. It can accommodate connecting flanges 420 of different thicknesses and radial outward projection dimensions. The preload screw 154 and preload nut 155 are used to preload and reinforce the distal end of the workpiece 400 with a high length-to-diameter ratio. The first annular member 151 has a threaded hole or a first opening, the second annular member 153 has a second opening, and the reinforcing seat 110 has a threaded hole. There are two or more second openings, distributed circumferentially around the axis of the first annular member 151. The number of second openings, threaded holes / first openings of the first annular member 151, and threaded holes of the reinforcing seat 110 are consistent and arranged opposite each other along the axial direction of the lathe spindle. The number of preload screws 154 is consistent with the number of second openings, and they pass through each other. The tail of the preload screw 154 passes through the first annular member 151, the second annular member 153, and the reinforcing seat 110 in sequence before connecting to the preload nut 155. If the second annular member 153 has a second opening, it passes through the second opening, connects to a preload nut 155, then passes through the reinforcing seat 110, and finally connects to the preload nut 155.

[0029] In one possible implementation, in the top support member, the contact area between the connecting portion 170 and the first friction member 211 is smaller than the contact area between the top support portion 160 and the workpiece 400. Optionally, the connecting portion 170 is a long rod, and the top support portion 160 is an arc-shaped plate for fitting against the outer wall of the workpiece 400, with one rod-shaped end of the connecting portion 170 fixed to the middle of the outer wall of the arc-shaped plate.

[0030] Optionally, the number of triboelectric generator sets in the triboelectric generator is consistent with the number of monitoring sections and they are arranged one-to-one. The first and second friction components 220 of the triboelectric generator set are both cylindrical. The first friction component 211 is coaxially sleeved outside the monitoring section of the cylindrical fixing part 100 and there is a first gap between the cylindrical walls. The second friction component 220 is coaxially sleeved outside the first friction component 211 and there is a second gap between the cylindrical walls. One end of the connecting part 170 is fixed to the inner wall of the first friction member 211. When there is no external force, the first friction member is always cylindrical. The workpiece 400, the cylindrical fixing part 100, the first annular groove 120, the first friction member 211, the second friction member 220 and the lathe spindle are coaxial. The top support is subjected to force and moves radially outward, so that the first friction member 211 deforms and contacts the second friction member 220, generating electricity through friction.

[0031] When the cylindrical workpiece 400 is subjected to force, the force is evenly distributed and buffered along the circumferential curved surface. This application does not specify the material selection or elastic buffering capacity of the first friction element 211, as long as it can elastically deform when the outward convexity of the workpiece 400 increases and plastic deformation occurs, and can return to a cylindrical shape after the external force disappears.

[0032] The above embodiments can only distinguish between elastic and plastic deformation of workpiece 400 by the presence and magnitude of power generation. The following embodiments can also make the above judgment by whether power is generated and the magnitude of the voltage, and can further distinguish between elastic and plastic deformation of workpiece 400 by the type of DC or AC power generated.

[0033] In one possible implementation, at the monitoring section, the number of triboelectric generator sets corresponds to the number of top support components. Each triboelectric generator set includes a first (circular) cylindrical component and a second (circular) cylindrical component. The inner wall of the first cylindrical component 210 has a friction layer serving as a first friction element 211, and the outer wall of the second cylindrical component has a friction layer serving as a second friction element 220. The axial directions of the first and second cylindrical components are aligned with the lathe spindle. The first cylindrical component 210 is nested outside the second cylindrical component. The radial cross-section of the triboelectric generator set is always an eccentrically nested circle, with the center of the eccentric circle located on a first straight line. The axis of the first cylindrical component 210 is close to the lathe spindle axis, while the axis of the second cylindrical component is far from the lathe spindle axis. Preferably, as follows... Figure 6As shown, one end of the triboelectric generator along the first straight line is its outermost end along the lathe spindle, where the first and second cylinders are closest, and the second cylinder is fixed to the inner wall of the first cylinder 210. The other end of the triboelectric generator along the first straight line is its innermost end along the lathe spindle, where the first and second cylinders are furthest apart. Optionally, the first cylinder 210 is entirely the first friction element 211 (a friction layer of the friction pair) of the triboelectric generator, and the second cylinder is also entirely the second friction element 220 (another friction layer of the friction element) of the triboelectric generator. At the outermost end of the triboelectric generator along the lathe spindle, the two are fixedly connected by an insulating layer 230 to achieve insulation between them. Along the circumference of the first friction layer, the first straight line is located in the middle of the insulating layer 230, and the two ends of the insulating layer 230 form a central angle, which is less than 180°. Alternatively, the entire second cylindrical component may be the second friction element 220, while the first cylindrical component 210 is an insulating component. A first friction element 211 is bonded to the inner wall of the first cylindrical component 210, with a circular arc-shaped cross-section that adheres to the inner wall of the first cylindrical component 210, extending as a continuous thin layer along the axial direction of the first cylindrical component 210. Along the circumference of the first cylindrical component 210, a first straight line is located at the center of the first friction element 211, and the central angle of the first friction element 211 is greater than 90° and less than or equal to 180°. Alternatively, the entire first cylindrical component 210 may be the first friction element 211, while the outer wall of the second cylindrical component may be bonded to the second friction element 220, as described above.

[0034] The first straight line of all radial sections of the triboelectric generator intersects perpendicularly with the axis of the lathe spindle. When there is no external force, the first cylinder 210 is not deformed, the first friction element 211 and the second friction element 220 are not in contact, and the triboelectric generator does not generate electricity. When the top support is subjected to force and moves radially outward, the first cylinder 210 is deformed, the first friction element 211 contacts the second friction element 220, and triboelectric generation occurs.

[0035] If the depth of cut is appropriate, the cutting force will generate a radial component, acting directly on the cutting position of the inner wall of the thin-walled cylindrical workpiece 400. Due to the thinness of the cylindrical wall and its extremely poor radial rigidity, this radial force will directly push the inner wall outward, causing the outer wall to bulge outward simultaneously. This is a typical elastic deformation of a thin-walled cylindrical part under a concentrated radial force. As the workpiece 400 rotates, the deformed cylindrical wall moves circumferentially away from the tool, the cylindrical wall springs back, and the outward bulge of the outer wall disappears. That is, the position of the radial outward bulge is constantly changing. Each triboelectric generator set distributed circumferentially has its own independent measuring device. If each triboelectric generator set generates electricity sequentially in the clockwise circumferential direction, the power generation signal of the generator set shows alternating current characteristics, which is elastic deformation. If electricity is generated sequentially in both directions on both sides of the circumference, it is wrinkling and stacking; if no more electricity is generated and no alternating current characteristics are detected in this generation, it is plastic deformation expansion, requiring work stoppage, disassembly, analysis of the cause, and adjustment of the construction process for the next workpiece 400.

[0036] The detector in this application uses a full-bridge rectifier circuit for rectification, and adjusts the voltage divider circuit according to actual conditions. A comparator is then used to compare the voltage values ​​to determine whether power is being generated. Alternatively, full-bridge rectification can be used, with the voltage divider circuit adjusted as needed, followed by a comparator comparison to determine the relationship between the real-time voltage and the first and second threshold values. Or, after rectification, peak voltage holding can be performed, followed by a comparator comparison to output high and low levels and feed them back to the controller. A zero-crossing detection circuit can also be set to monitor whether the generator output is AC, and simultaneously determine whether power is being generated using the above methods. One cycle is defined as the time from the start to the stop of power generation. If a zero-crossing signal (positive / negative signal transition) is detected within one generation cycle, it is AC, and normal turning is possible. If no zero-crossing signal is detected within one generation cycle, it is DC, and the workpiece cannot elastically deform and recover its state, requiring work stoppage, disassembly, and analysis of the cause.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A turning mechanism for machining cylindrical thin-walled workpieces, characterized in that, The device includes a fixture for fixing the workpiece to an inner bore during machining. The fixture includes a cylindrical fixing part and a triboelectric generator. The fixing part is fitted and sleeved on the outer wall of the workpiece. Along the axial direction of the fixing part, one end of the fixing part is fixed to the lathe spindle of the turning device. A monitoring section is provided in the middle, located at the weak point of the workpiece during the inner bore machining process. The inner side of the cylindrical section of the monitoring section is provided with a first annular groove, and the outer wall of the cylindrical section is provided with a radial guide hole. The workpiece, the cylindrical fixing part, the first annular groove and the lathe spindle are coaxial. The monitoring section is equipped with a triboelectric generator set of the triboelectric power generation device. The triboelectric generator set includes a first friction element and a second friction element, both mounted on a cylindrical fixing part and insulated from the workpiece and the cylindrical fixing part. The monitoring section also has two or more top supports, the number of which corresponds to the number of radial guide holes. Each top support includes a top support portion and a connecting portion. The top support portion is located within a first annular groove, with one side facing and fitting against the cylindrical outer wall of the workpiece. All top supports together cover the entire circumference of the workpiece corresponding to the monitoring section. One end of the connecting portion is fixed to the other side of the top support portion. The other end extends along the diameter direction corresponding to its corresponding radial guide hole, movably passing through the radial guide hole, and one end is fixed to the first friction member. In the triboelectric generator set, the first friction member and the second friction member are arranged opposite each other along the radial movement direction of the connecting part on the first friction member. When there is no external force, the first and second friction members of the triboelectric generator set are not in contact. The top support member is subjected to force and moves radially outward, causing the first friction member to deform and contact the second friction member, thus generating triboelectric power. The triboelectric generator set is also equipped with a detector for real-time monitoring and feedback of the triboelectric power generation status of its first and second friction members to the controller of the turning device. The controller adjusts the turning state accordingly.

2. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, The detector is used to compare the peak voltage generated by the triboelectric generator with a first threshold and a second threshold. If the second threshold is less than the peak voltage generated by the triboelectric generator and less than the first threshold, the controller generates a control command to reduce the depth of cut. If the peak voltage generated by the triboelectric generator is greater than or equal to the first threshold, the controller generates a control command to stop processing.

3. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, The workpiece is a workpiece with its outer diameter turned. One axial end of the workpiece has an external thread. One axial end of the cylindrical fixing part is connected to the lathe spindle. This end has an internal thread for connecting with the external thread at the axial end of the workpiece.

4. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, The workpiece is a workpiece with its outer diameter turned. One axial end of the workpiece is away from the lathe spindle and has a connecting flange. The other axial end of the workpiece faces the lathe spindle and is installed on the lathe spindle by the fixing device. The fixing device also includes a reinforcing member. The reinforcing member is clamped and fixed to the annular convex wall of the connecting flange. The cylindrical outer wall of the cylindrical fixing part is provided with a reinforcing seat along the axial direction of the lathe spindle. There is a preset distance between the reinforcing seat and the reinforcing member. The reinforcing seat is located between the lathe spindle and the reinforcing member. The reinforcing member and the reinforcing seat are pre-tightly connected.

5. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 4, characterized in that, The reinforcing member and the reinforcing seat are pre-tightened bolts.

6. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, The workpiece is a workpiece with its outer diameter machined. One axial end of the workpiece has an axially extending protrusion forming a shoulder. The root of the protrusion has a second annular groove with the groove opening radially outward. The inner wall of the cylindrical fixing part has a third annular groove. The second and third annular grooves are arranged opposite to each other. The fixing device also includes a retaining spring. The retaining spring is sleeved in the second annular groove of the workpiece and passes through the third annular groove. The retaining spring is no longer squeezed by the cylindrical wall and naturally expands outward. The outer annular side of the retaining spring protrudes outward from the side wall of the workpiece and extends into the second annular groove, while the inner annular side is still in the third annular groove. An operating port is provided through the outer annular side of the third annular groove for operating the retaining spring to release its axial limitation.

7. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, In the top support member, the contact area between the connecting part and the first friction member is smaller than the contact area between the top support member and the workpiece.

8. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 7, characterized in that, The connecting part is a long rod, and the top support part is an arc-shaped plate used to fit the outer wall of the workpiece. One rod-shaped end of the connecting part is fixed to the middle of the outer wall of the arc-shaped plate.

9. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, The number of triboelectric generator sets in the triboelectric generator is the same as the number of monitoring sections and they are arranged one to one. The first and second friction components of the triboelectric generator set are both cylindrical. The first friction component is coaxially sleeved outside the monitoring section of the cylindrical fixed part and there is a first gap between the cylindrical walls. The second friction component is coaxially sleeved outside the first friction component and there is a second gap between the cylindrical walls. One end of the connecting part is fixed to the inner wall of the first friction element. When not subjected to external force, the first friction element is always cylindrical. The workpiece, the cylindrical fixing part, the first annular groove, the first friction element, the second friction element and the lathe spindle are coaxial. The top support is subjected to force and moves outward radially, causing the first friction element to deform and contact the second friction element, thus generating electricity through friction.

10. The turning mechanism for machining cylindrical thin-walled workpieces according to claim 1, characterized in that, At the monitoring section, the number of triboelectric generator sets is consistent with the number of top support members and is set in a one-to-one correspondence. Each triboelectric generator set includes a first cylindrical member and a second cylindrical member. The inner wall of the first cylindrical member has a friction layer as a first friction member, and the outer wall of the second cylindrical member has a friction layer as a second friction member. The axial directions of the first and second cylindrical members are consistent with the lathe spindle. The first cylindrical member is nested outside the second cylindrical member. The radial cross-section of the triboelectric generator set is always eccentrically nested, and the center of the eccentric circle is located on a first straight line. The first straight line of all radial cross-sections of the triboelectric generator set intersects perpendicularly with the lathe spindle axis. The axis of the first cylindrical member is close to the lathe spindle axis, and the axis of the second cylindrical member is far from the lathe spindle axis. When there is no external force, the first cylindrical member does not deform, the first friction member and the second friction member do not contact each other, and the triboelectric generator set does not generate electricity. When the top support member is subjected to force, it moves radially outward, causing the first cylindrical member to deform. The first friction member contacts the second friction member, and triboelectric generation occurs.

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