Automatic telescopic reverse counter boring cutter

Abstract

The invention discloses an automatic telescopic reverse countersinking cutter, relates to the technical field of reverse countersinking cutters, and aims to solve the technical problems that machining accidents occur due to inaccurate positioning during reverse countersinking, and the machining efficiency is influenced by cutter avoiding action. The invention has the following advantages: firstly, the step of feeding without avoiding is realized through the automatic retraction and release of the tool apron, the redundant operation is omitted, and the processing efficiency is greatly improved; 2, a two-stage elastic buffer structure is designed, so that hard collision caused by positioning deviation is effectively avoided, and the loss of cutters, workpieces and equipment is reduced; thirdly, head and tail dual axis positioning protection is adopted, the axis deviation problem of sliding connection is solved, and the counter sinking machining precision is remarkably improved; fourthly, cutting heat recycling multi-stage utilization is achieved, passive autonomous operation is achieved in the whole process, and external power and manual intervention are not needed; and fifthly, a whole-course uninterrupted positive pressure protection system is constructed, the overall service life of the tool is greatly prolonged, and the machining efficiency, precision, safety and equipment durability are all considered.

Description

An automatic telescopic reverse counterboring tool Technical Field

[0001] This invention relates to the field of reverse countersinking technology, and more specifically, to an automatic telescopic reverse countersinking tool. Background Technology

[0002] Countersinking tools, as core tools in the machining field, are mainly used to countersink pre-drilled holes to create a flat hole surface or a specific countersunk structure, adapting to the installation requirements of fasteners such as bolts and nuts, and ensuring the flatness and reliability of workpiece assembly. Reverse countersinking, as a special machining process, involves countersinking holes on the back of a workpiece or in specific structures. It is a common machining step in industries such as aerospace, automotive manufacturing, and precision mold making, and has strict requirements for machining accuracy and efficiency.

[0003] The current reverse counterboring tool workflow generally relies on the traditional operation mode of "coordinate positioning - tool avoidance and retreat - reset machining", which has significant technical defects and seriously affects machining quality and production efficiency. First, the positioning process needs to be completed manually, and the accuracy of manual positioning is difficult to guarantee, which easily leads to coordinate positioning deviation. Once the positioning is incorrect, the positioning deviation may cause direct collision between the tool and the workpiece, resulting in tool chipping, workpiece scrap, or even failure of machining equipment, causing huge economic losses.

[0004] Secondly, to avoid collisions between the tool and workpiece during the feed process, a tool avoidance and retraction step must be added to the traditional process. This involves shifting the tool to a safe coordinate after positioning, and then resetting it to start machining after passing through the hole. This extra step significantly extends the machining cycle time, reduces overall machining efficiency, and fails to meet the demands of modern manufacturing for high-efficiency production. Furthermore, multiple coordinate shifting and resetting operations introduce cumulative errors, further affecting the machining accuracy of reverse counterboring and making it difficult to adapt to the machining standards of high-precision workpieces.

[0005] The subjectivity of existing manual positioning and the redundancy of tool avoidance steps jointly limit the quality and efficiency of reverse countersinking. Therefore, we propose an automatically telescopic reverse countersinking tool. Summary of the Invention

[0006] The purpose of this invention is to provide an automatic telescopic reverse countersinking tool to solve the technical problems of machining accidents caused by inaccurate positioning during reverse countersinking and the impact of tool avoidance actions on machining efficiency.

[0007] To solve the above technical problems, the present invention provides the following technical solution: an automatic telescopic reverse counterboring tool, comprising a main sleeve, a tool shank fixed at the center of the main sleeve, a telescopic tool tube at one end of the main sleeve, the telescopic tool tube being sleeved around the outer periphery of the tool shank, the telescopic tool tube and the main sleeve being in a limited sliding relationship, a fixing ring fixed around the outer periphery of the tool shank, a telescopic spring connected between the fixing ring and the telescopic tool tube, a secondary telescopic component being provided around the outer periphery of the telescopic spring and sliding in a limited sliding relationship with the main sleeve, the secondary telescopic component being composed of a sliding sleeve and a backing seat, the backing seat being... Compression springs and tenons are staggered between the top seat and the sliding sleeve. The sliding sleeve and the telescopic cutter tube are connected by a telescopic and limiting sliding connection. A constraint head is fixed on the outer periphery of the main sleeve to constrain the movement distance of the back top seat. A receiving groove is opened at the end of the cutter bar. A notch is opened near the receiving groove of the telescopic cutter tube. A central shaft is rotatably connected inside the receiving groove. A cutter holder is fixed on the outer periphery of the central shaft. A blade is detachably connected to the side of the cutter holder. A side bevel is opened on the cutter holder. A torsion spring is provided on one side of the side bevel and surrounds the central shaft.

[0008] Preferably, the tool holder has a curved groove near the tool holder, and a curved locking block adapted to the curved groove is connected to one side of the tool holder. A shaft stabilizing mechanism is provided between the fixing ring and the main sleeve, and a temperature difference sensing mechanism for providing energy is provided on the outside of the shaft stabilizing mechanism.

[0009] Preferably, the shaft stabilizing mechanism includes a positioning ring fixed to the fixed ring and the main sleeve. The positioning ring has an annular structure, and a movable ring is provided on one side of the positioning ring. A top support plate is connected between the movable ring and the inner and outer circumferential sides of the positioning ring. The top support plate and the fixed ring or the main sleeve are designed to fit together for stabilizing the shaft.

[0010] Preferably, the top support piece has a multi-wave structure, and the top support piece on the inner circumference is integrally formed with a protrusion. The outer circumference of the fixing ring is provided with multiple grooves of the same size as the protrusion. A disk for conducting current is fixed between one side of the multiple top support pieces. The top support piece can be transformed from martensitic to austenitic with higher hardness and inserted into the groove under the influence of current.

[0011] Preferably, the temperature difference sensing mechanism includes a thermoelectric element, a supercapacitor connected to one side of the thermoelectric element, a flexible PI micro PCB board connected to the supercapacitor via electrode pins, the flexible PI micro PCB board being fixed inside the main sleeve, a voltage comparator and a current-limiting resistor being mounted on the flexible PI micro PCB board, and the current-limiting resistor being connected to the disk.

[0012] Preferably, the cutter bar is coated with a heat-insulating coating except for the curved groove and the thermoelectric element position, and the thermoelectric element is attached to the outer wall of the cutter bar and the inner wall of the telescopic cutter tube on both sides.

[0013] Preferably, an expansion airbag is bonded between the multiple top support plates, and an anti-chip mechanism is provided on one side of the expansion airbag. Multiple micro air passages are opened on the outer periphery of the tool holder.

[0014] Preferably, the anti-dumping mechanism includes a piston ring fixed to a positioning ring, a piston plate inside the piston ring, a return spring connected between the piston plate and the piston ring, an air outlet area and an air return area on both sides of the piston plate, a flow restrictor connecting the air outlet area and the micro air passage to limit the air flow, and an air inlet pipe fixed between the temperature difference sensing mechanism and the air outlet area.

[0015] Preferably, the air intake pipe is equipped with a first one-way valve that can only supply air to the air outlet area, the air return area is connected to the inflatable air bladder by a second one-way valve that supplies air to the inflatable air bladder, the air return area is connected to the outside by a differential pressure valve, and a limit post is installed on the inner wall of the air return area.

[0016] Preferably, the micro-air passage is surrounded by a telescopic tube in the area of ​​the inner circumference of the main sleeve, and the telescopic tube is a tenon-type telescopic structure.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention, through the cooperation of the tool holder end receiving groove, the rotatable tool holder and the torsion spring, allows the telescopic tool tube to press against the tool holder during the cutting process, causing the blade to automatically retract into the receiving groove. There is no need for manual operation to deflect the tool to a safe coordinate, and the cutting can be completed by directly passing through the workpiece hole. This completely eliminates the redundant tool avoidance steps of "coordinate positioning - tool avoidance retreat - reset processing" in the traditional reverse counterboring process, greatly shortening the single-process processing cycle time. At the same time, the automatic retraction and extension of the tool holder is driven by mechanical pressure and spring force, without the need for external electrical control components. The action response is accurate and without delay, which is suitable for continuous batch processing requirements, effectively improving the overall production efficiency of reverse counterboring and meeting the high-efficiency processing standards of modern manufacturing industry.

[0018] 2. This invention addresses the problem of deviations and hard collisions between the tool and workpiece caused by manual positioning of traditional cutting tools. The tool is designed with an elastic protection structure consisting of a primary buffer (extension spring) and a secondary buffer (extension component). When positioning deviations occur, the telescopic tool tube first compresses the extension spring to achieve initial collision avoidance. When the resistance is greater, the compression spring of the secondary buffer contracts to complete the secondary buffering, transforming the hard collision into elastic contact. Simultaneously, the constraint head limits the maximum movement distance of the secondary buffer, preventing structural dislocation. This effectively prevents tool chipping, tool holder deformation, and workpiece scrapping, while also reducing the impact of collisions on the machine tool spindle, lowering wear and tear on machining equipment, reducing economic losses due to machining accidents, and improving the stability and safety of the machining process.

[0019] 3. This invention addresses the problem of axial instability and misalignment that easily occurs during prolonged use of the sliding connection between the telescopic tool tube and the tool holder. This tool achieves pre-positioning of the tool holder's front end through a curved groove and a curved retaining block, limiting radial misalignment of the tool holder and forming local support. Simultaneously, it utilizes the self-powered energy from the temperature difference of the cutting heat to drive the deformation of the NiTi alloy top support plate, forming radial full-circumferential support and longitudinal positioning in the middle and rear sections. This double protection at both ends completely prevents relative misalignment between the tool holder and the telescopic tool tube. After deformation, the top support plate is in a high-hardness austenitic state, which can effectively counteract the radial vibration force during cutting, ensuring coaxiality during machining and avoiding problems such as uneven countersink end faces and dimensional deviations caused by axial misalignment. This significantly improves the machining accuracy of reverse countersinking and is suitable for machining high-precision workpieces.

[0020] 4. This invention utilizes the high temperature generated by the cutting blade to convert the temperature difference between the tool holder and the telescopic tool tube into electrical energy through a thermoelectric element. After being stored in a supercapacitor and triggered by a voltage comparator threshold, this electrical energy provides deformation current to the top support plate of the shaft stabilization mechanism, realizing the resource utilization of cutting heat without the need for an external power supply. At the same time, the deformation of the top support plate directly drives the expansion airbag and the chip-proof mechanism, converting deformation energy into pneumatic power to provide a power source for chip protection, thus realizing multi-level energy utilization. The entire linkage process of temperature difference power supply, shaft stabilization, and chip protection is realized through the inherent physical characteristics of the components and circuit logic, without the need for external programs, electrical control modules, or manual intervention. It is compatible with various processing equipment, reducing the operating threshold and usage costs.

[0021] 5. This invention addresses the problem of coolant and chip intrusion into the sliding gap due to capillary action and negative pressure. This tool utilizes a top support plate deformation linkage with an expanding and contracting airbag for exhaust, combined with a flow-limiting port for flow stabilization and a piston plate for energy storage, forming a two-stage air supply. This continuously delivers gas to the sliding gap, creating a micro-positive pressure air curtain that completely counteracts negative pressure and disrupts the capillary tension of the coolant. A tenon-type telescopic sleeve ensures no air leakage in the air path. The piston plate resets, providing secondary air compression, and the expanding and contracting airbag replenishes the air, ensuring positive pressure is maintained in the gap under all operating conditions, including cutting, retraction, and collision avoidance. This prevents coolant and chip intrusion, effectively avoiding jamming and damage to the sliding pair due to abrasive wear and corrosion. Simultaneously, it protects the electronic components of the temperature sensing mechanism from contamination, significantly extending the service life of all tool components, reducing daily maintenance and replacement costs, and improving the overall efficiency of the tool. Attached Figure Description

[0022] Figure 1 is a schematic diagram of the structure of the present invention.

[0023] Figure 2 is a schematic diagram of the internal structure along the direction of the temperature difference sensing mechanism in this invention.

[0024] Figure 3 is a schematic diagram of a half-section structure along the direction of the temperature difference sensing mechanism in this invention.

[0025] Figure 4 is a schematic diagram of a half-section structure along the direction of the constraint head in this invention.

[0026] Figure 5 is an enlarged view of the structure at point A in Figure 4 of this invention.

[0027] Figure 6 is a schematic diagram of the half-section structure of the chip-preventing mechanism and the shaft stabilizing mechanism in this invention.

[0028] Figure 7 is an enlarged view of the structure at point B in Figure 6 of this invention.

[0029] Figure 8 is a schematic diagram of the axial stabilizing mechanism in this invention.

[0030] Figure 9 is an enlarged view of the structure at point C in Figure 8 of this invention.

[0031] Figure 10 is a schematic diagram of the fit between the top support plate and the fixing ring in this invention.

[0032] Figure 11 is a schematic diagram of the state structure of the shaft stabilization mechanism and the chip prevention mechanism of the present invention in operation.

[0033] Figure 12 is a schematic diagram of the cooperation structure between the knife bar and the telescopic tube in this invention.

[0034] Figure 13 is a schematic diagram of the half-section structure of the knife bar and telescopic tube in this invention.

[0035] Explanation of the numbers in the diagram: 1. Main sleeve; 2. Tool holder; 21. Micro air passage; 3. Telescopic tool tube; 4. Fixing ring; 5. Telescopic spring; 6. Secondary telescopic component; 601. Sliding sleeve; 602. Backrest; 603. Compression spring; 604. Tenon; 7. Constraint head; 8. Receiving groove; 901. Central shaft; 902. Tool holder; 903. Tool; 904. Torsion spring; 905. Side bevel; 10. Curved block; 11. Shaft stabilization mechanism; 12. Temperature difference sensing mechanism; 13. Inflatable airbag; 14. Chip prevention mechanism; 15. Telescopic sleeve ; 111, Positioning ring; 112, Movable ring; 113, Top support plate; 114, Convex clip; 115, Groove; 116, Disc; 121, Thermoelectric element; 122, Supercapacitor; 123, Flexible PI micro PCB board; 124, Voltage comparator; 125, Current limiting resistor; 141, Piston ring; 142, Piston plate; 1421, Exhaust area; 1422, Return area; 143, Flow limiting port; 144, Intake pipe; 1451, First check valve; 1452, Second check valve; 146, Differential pressure valve; 147, Limiting post. Detailed Implementation

[0036] As shown in Figures 1 to 13, the present invention relates to an automatic telescopic reverse counterboring tool, comprising a main sleeve 1, a tool shank 2 fixed at the center of the main sleeve 1, a telescopic tool tube 3 at one end of the main sleeve 1, the telescopic tool tube 3 being sleeved around the outer periphery of the tool shank 2, and the telescopic tool tube 3 sliding with the main sleeve 1 in a limited manner; a fixing ring 4 is fixed around the outer periphery of the tool shank 2, and a telescopic spring 5 is connected between the fixing ring 4 and the telescopic tool tube 3; a secondary telescopic component 6 is provided around the outer periphery of the telescopic spring 5, which slides with the main sleeve 1 in a limited manner; the secondary telescopic component 6 consists of a sliding sleeve 601 and a back support 602; compression springs 603 and tenon bars 604 are alternately distributed between the back support 602 and the sliding sleeve 601; the sliding sleeve 601... The main sleeve 1 and the telescopic cutter tube 3 are connected by a telescopic limit sliding connection. The outer periphery of the main sleeve 1 is fixed with a constraint head 7 that restricts the movement distance of the back top seat 602. The constraint head 7 can limit the maximum movement distance of the back top seat 602 to prevent the secondary telescopic component 6 from excessively contracting and causing structural dislocation. The end of the cutter bar 2 is provided with a receiving groove 8. The telescopic cutter tube 3 is provided with a notch near the receiving groove 8. The receiving groove 8 is rotatably connected to a central shaft 901. The outer periphery of the central shaft 901 is fixed with a cutter holder 902. The side of the cutter holder 902 is detachably connected with a blade 903. The cutter holder 902 is provided with a side bevel 905. A torsion spring 904 is provided on one side of the side bevel 905 and surrounds the central shaft 901.

[0037] Working principle: When the tool moves towards the hole to be machined on the workpiece, the front end of the telescopic tool tube 3 first contacts the workpiece hole / end face. The resulting pressure is transmitted to the rotatable tool holder 902 at the end of the tool holder 2. After being pressed, the tool holder 902 rotates along the central axis 901. The torsion spring 904 is simultaneously twisted and stored. The tool holder 902, together with the cutting tool 903, gradually rotates and retracts into the receiving groove 8 at the end of the tool holder 2. The notch of the telescopic tool tube 3 provides sufficient space for the tool holder 902 to rotate and retract. During this process, the cutting tool 903 is completely housed in the receiving groove 8, realizing automatic avoidance during tool entry. There is no need for manual operation to deflect the tool to a safe coordinate. It can directly pass through the hole of the workpiece, greatly simplifying the tool entry process.

[0038] When the cutting tool passes through the workpiece hole and reaches the reverse counterboring position, the telescopic cutting tool tube 3 loses the pressure constraint of the workpiece. The elastic restoring force of the telescopic spring 5 pushes the telescopic cutting tool tube 3 to slide forward and return to its original position along the outer circumference of the tool holder 2. At the same time, the tool holder 902 loses the pressure, and the torsion spring 904 releases the torsional stored force, causing the tool holder 902 to rotate in the opposite direction along the central axis 901. The cutting tool 903 extends out from the receiving groove 8 and fits against the end face of the workpiece to be counterbored. At this time, the cutting tool is started to rotate, and the cutting tool 903 performs reverse counterboring on the workpiece hole. During the processing, the telescopic cutting tool tube 3 and the main sleeve 1 are in a limiting sliding fit to ensure the positional stability of the cutting tool 903 during processing and avoid processing deviation.

[0039] If a coordinate positioning deviation occurs during machining, and the tool does not align with the workpiece hole and directly contacts the hard surface of the workpiece, the first elastic contraction is activated: after the telescopic tool tube 3 is subjected to the workpiece's resistance pressure, the compressed telescopic spring 5 slides and contracts along the outer circumference of the tool holder 2 towards the main sleeve 1, achieving initial collision avoidance; if the resistance pressure is large, the sliding of the telescopic tool tube 3 will drive the sliding sleeve 601 of the secondary telescopic component 6 to move synchronously, and the second elastic contraction is activated: the sliding sleeve 601 compresses the compression spring 603 between the back top seat 602 and itself, and the tenon 604 slides to a limit position as the compression spring 603 contracts, achieving secondary buffer contraction. Through two stages of elastic telescopic buffering, the hard collision between the tool and the workpiece is transformed into elastic contact, completely avoiding tool chipping, workpiece scrapping, and equipment failure.

[0040] Furthermore, although the above structure achieves the functions of tool feed avoidance and collision buffering, the telescopic tool tube 3 and the tool holder 2 are slidably connected. However, when used for a long time, the axis of the tool holder 2 is prone to instability and axis offset.

[0041] The tool holder 2 has a curved groove near the tool holder 902. A curved locking block 10 that matches the curved groove is connected to one side of the tool holder 902. After the tool is assembled, the curved locking block 10 on one side of the tool holder 902 is precisely matched and engaged with the curved groove on the tool holder 2. This structure directly restricts the radial displacement of the tool holder 902 and forms a local positioning support for the end of the tool holder 2. The pre-positioning of the front end of the tool holder 2 is achieved before cutting, reducing the axial wobbling of the tool holder 2 due to the lack of support at the front end, and laying the foundation for the subsequent overall axial stability.

[0042] A shaft stabilizing mechanism 11 is provided between the fixed ring 4 and the main sleeve 1, and a temperature difference sensing mechanism 12 for providing energy is provided on the outside of the shaft stabilizing mechanism 11.

[0043] The shaft stabilizing mechanism 11 includes a positioning ring 111 fixed to the fixed ring 4 and the main sleeve 1. The positioning ring 111 has an annular structure. A movable ring 112 is provided on one side of the positioning ring 111. A top support plate 113 is connected between the movable ring 112 and the inner and outer circumferential sides of the positioning ring 111. The top support plate 113 and the fixed ring 4 or the main sleeve 1 are designed to fit together for stabilizing the shaft.

[0044] The top support plate 113 has a multi-wave structure. The top support plate 113 on the inner circumference is integrally formed with a protrusion 114. The outer circumference of the fixing ring 4 has multiple grooves 115 with the same size as the protrusion 114. A disc 116 for conducting current is fixed between one side of the multiple top support plates 113. Under the influence of current, the top support plate 113 can be transformed from martensitic to austenitic with higher hardness and be inserted into the groove 115.

[0045] The top support plate 113 is preferably a bidirectional nickel-titanium shape memory alloy (NiTi alloy, titanium-nickel alloy), with a specific grade recommended as NiTi-50.8at%Ni. It undergoes a rapid phase transformation (martensite → austenite) under microcurrent, resulting in high hardness and rigidity after deformation, stable support, and excellent conductivity, making it suitable for the conductivity of the 116 disc.

[0046] The temperature difference sensing mechanism 12 includes a thermoelectric element 121. A supercapacitor 122 is connected to one side of the thermoelectric element 121. The supercapacitor 122 is connected to a flexible PI micro PCB board 123 through electrode pins. The flexible PI micro PCB board 123 is fixed inside the main sleeve 1. A voltage comparator 124 and a current limiting resistor 125 are installed on the flexible PI micro PCB board 123. The current limiting resistor 125 is connected to the disk 116.

[0047] To increase the temperature difference, the tool holder 2 is coated with a heat insulation coating except for the curved groove and the position of the thermoelectric element 121. The thermoelectric element 121 is attached to the outer wall of the tool holder 2 and the inner wall of the telescopic tool tube 3 on both sides.

[0048] Working principle: After the tool starts reverse counterboring, the cutting friction between the insert 903 and the workpiece generates a large amount of high temperature. The heat is quickly conducted to the tool holder 2 body. Except for the curved groove and the contact position of the thermoelectric element 121, the rest of the tool holder 2 is coated with a heat insulation coating, which effectively prevents the heat from spreading to non-critical areas and ensures that the temperature of the hot end of the thermoelectric element 121 (attached to the outer wall of the tool holder 2) rises rapidly. Meanwhile, the cold end of the thermoelectric element 121 is attached to the inner wall of the telescopic tool tube 3. The telescopic tool tube 3 is an exposed structure and is in full contact with the air, so it always maintains a low temperature. This creates a stable temperature difference on both sides of the thermoelectric element 121 (mainly used for long-term deep counterboring or large-diameter counterboring).

[0049] Temperature difference drives thermoelectric element 121 to generate microcurrent, which is directly delivered to supercapacitor 122 for energy storage. Voltage comparator 124 on flexible PI micro PCB board 123 monitors the voltage of supercapacitor 122 in real time. When the voltage reaches the preset threshold of deformation of top support piece 113, the subsequent power supply process is automatically triggered, realizing the resource utilization of cutting heat throughout the process, without external power supply or additional energy consumption.

[0050] When the voltage of the supercapacitor 122 reaches the threshold, the voltage comparator 124 turns on the circuit. After the current is limited by the current-limiting resistor 125, the current is evenly delivered to all the top support plates 113 through the conductive disk 116. The top support plates 113 are made of shape memory alloy. After the current is applied, they are rapidly Joule heated, and a phase transformation from martensite to austenite occurs, which greatly improves the hardness and rigidity. At the same time, the top support plates 113 with multiple wave-shaped structures undergo directional stretching deformation, which drives the integrally formed convex clip 114 to accurately fit into the groove 115 on the outer periphery of the fixing ring 4. During this process, the positioning ring 111 serves as the fixed base, and the movable ring 112 moves adaptively with the deformation of the top support plates 113. Finally, the top support plates 113 are tightly fitted with the fixing ring 4 and the main sleeve 1, completing the preparation for the axial locking of the tool holder 2.

[0051] After deformation, the top support plate 113 is in a high-hardness austenitic state, and the engagement of the convex clip 114 and the groove 115 forms a longitudinal positioning, restricting the axial movement of the tool holder 2. At the same time, the inner and outer peripheral top support plates 113 between the positioning ring 111 and the movable ring 112 are tightly fitted with the fixed ring 4 and the main sleeve 1, respectively, forming a radial full-circumferential support, which counteracts the radial vibration force generated during tool rotation from multiple directions and prevents the relative displacement between the tool holder 2 and the telescopic tool tube 3. The pre-positioning of the front end of the curved groove + curved clip 10 and the radial + longitudinal fixation of the middle and rear sections of the top support plate 113 form a double protection at both ends, solving the problem of axial instability and displacement after long-term use of the sliding connection between the telescopic tool tube 3 and the tool holder 2, and ensuring coaxiality during processing.

[0052] After the countersinking is completed, the cutting tool 903 stops cutting, the temperature of the tool holder 2 gradually decreases, the temperature difference between the two sides of the thermoelectric element 121 disappears, and the current stops being generated. After the supercapacitor 122 has finished discharging, the voltage comparator 124 automatically shuts off the circuit. After the top support plate 113 loses the current heating, it cools naturally through heat conduction with the tool holder 2 and the telescopic tool tube 3. After the temperature drops below the phase transformation temperature, the top support plate 113 undergoes a reverse phase transformation from austenite to martensite, the hardness decreases, and it returns to the initial multi-wave-shaped contraction state. The convex clip 114 disengages from the groove 115, releasing the radial and longitudinal fixation of the tool holder 2. The locking and resetting are completely synchronized with the tool processing flow without any functional interference.

[0053] Furthermore, although the above structure achieves the functions of tool feed avoidance and collision buffering, the sliding gap between the telescopic tool tube 3 and the tool holder 2 will generate capillary and negative pressure during cutting, causing coolant and debris to enter the gap and damage the parts.

[0054] Multiple top support plates 113 are bonded together with expansion airbags 13, and a chip prevention mechanism 14 is provided on one side of the expansion airbags 13. Multiple micro air passages 21 are opened on the outer periphery of the tool bar 2.

[0055] The anti-dumping mechanism 14 includes a piston ring 141 fixed to the positioning ring 111. A piston plate 142 is provided inside the piston ring 141. A return spring is connected between the piston plate 142 and the piston ring 141. An air outlet area 1421 and an air return area 1422 are respectively provided on both sides of the piston plate 142. An air flow limiting port 143 is connected between the air outlet area 1421 and the micro air passage 21 to limit the air flow. An air inlet pipe 144 is fixed between the temperature difference sensing mechanism 12 and the air outlet area 1421.

[0056] The intake pipe 144 is equipped with a first one-way valve 1451 that can only supply air to the exhaust area 1421. The return area 1422 is connected to the inflatable airbag 13 by a second one-way valve 1452 that supplies air to the inflatable airbag 13. The return area 1422 is connected to the outside by a differential pressure valve 146. A limit post 147 is installed on the inner wall of the return area 1422. The limit post 147 can limit the maximum movement distance of the piston plate 142, prevent the return spring from fatigue and breakage due to excessive stretching, and avoid hard collision between the piston plate 142 and the piston ring 141.

[0057] To ensure that the airflow does not leak along the path, the micro air passage 21 is wrapped with a telescopic tube 15 in the area of ​​the inner circumference of the main sleeve 1. The telescopic tube 15 is a tenon-type telescopic structure.

[0058] Working principle: During the cutting process, the temperature difference sensing mechanism 12 supplies power to the top support plate 113. The top support plate 113 undergoes a phase transformation from martensite to austenite and undergoes directional stretching deformation. The stretching of its multiple wave-shaped structure will compress the expansion bladder 13 that is bonded to itself, causing the volume of the expansion bladder 13 to shrink rapidly. After being compressed, the gas in the expansion bladder 13 is quickly transported to the intake pipe 144 through the pipeline. The first one-way valve 1451 on the intake pipe 144 only allows the gas to flow unidirectionally to the outlet area 1421 of the piston ring 141, effectively preventing gas backflow and ensuring stable exhaust pressure.

[0059] The compressed gas entering the outlet area 1421 is partially limited and stabilized by the flow limiting port 143 before being delivered to the micro-air passage 21 on the outer periphery of the tool holder 2. The micro-air passage 21 is distributed around the tool holder 2. The gas is evenly blown from the outlet of the micro-air passage 21 to the sliding gap between the telescopic tool tube 3 and the tool holder 2, forming an initial positive pressure air curtain in the gap. This directly counteracts the local negative pressure generated by the rotation and extension of the tool during cutting, while also breaking the capillary tension of the coolant. This prevents the coolant and chips from seeping into the gap from the source. Furthermore, the area of ​​the micro-air passage 21 located on the inner periphery of the main sleeve 1 is wrapped with a tenon-type telescopic sleeve 15, which can adapt to the relative sliding of the tool holder 2 and the telescopic tool tube 3. The micro-air passage 21 is completely wrapped to ensure that there is no leakage of gas in the transmission path and to ensure positive pressure gas supply efficiency.

[0060] Due to the flow restriction of the flow limit port 143, the gas in the outlet area 1421 cannot be completely discharged instantly. As the inflating airbag 13 continues to discharge gas, the gas pressure in the outlet area 1421 gradually increases. The high-pressure gas pushes the piston plate 142 to move towards the return area 1422. The return spring between the piston plate 142 and the piston ring 141 is stretched and stored in force. During this process, the movement of the piston plate 142 will continuously compress the gas in the outlet area 1421. Even after the inflating airbag 13 has finished discharging gas, the piston plate 142 can still continuously supply gas to the micro-air passage 21 under the dual action of gas pressure and the tension of the return spring, ensuring that the positive pressure air curtain of the sliding gap is not interrupted, and realizing "one-time inflation, continuous gas supply".

[0061] After the countersinking is completed, the temperature difference sensing mechanism 12 stops supplying power, the top support plate 113 cools naturally and undergoes a reverse phase transformation from austenite to martensite, returning to its initial multi-wave-shaped contraction state. The compressive force on the expansion bladder 13 disappears, and the volume of the expansion bladder 13 gradually expands as the top support plate 113 resets, forming a negative pressure inside and producing a suction effect. At this time, the differential pressure valve 146 connecting the return gas area 1422 and the outside automatically opens due to the internal and external pressure difference. Clean air from the outside enters the return gas area 1422 through the differential pressure valve 146, and is then drawn into the expansion bladder 13 through the second one-way valve 1452 (which only allows gas to flow unidirectionally to the expansion bladder 13), completing the replenishment of the expansion bladder 13 and preparing for the next exhaust.

[0062] At the same time, after the top support plate 113 is reset, the air pressure in the air outlet area 1421 decreases, the stretched reset spring releases its stored force, and pulls the piston plate 142 back to its initial position. During the return process, the piston plate 142 will squeeze the remaining gas in the air outlet area 1421 again and pressurize it to the micro air passage 21 for secondary air compression, further ensuring that the sliding gap still has positive pressure protection during the tool retraction / collision avoidance stage, and avoiding the negative pressure of the gap during tool retraction to suck up chips.

[0063] As described above, when the tool enters the next cutting operation, the top support plate 113 deforms again to compress the expanding air bag 13, repeating the above-mentioned cycle of "exhausting - pressurizing - storing energy - supplying air - resetting - drawing in air - replenishing air". Throughout the process, the expansion and contraction of the expanding air bag 13 is completely synchronized with the deformation of the top support plate 113. The reciprocating movement of the piston plate 142 and the steady flow output of the flow limiting port 143 form a "dual-stage air supply", so that the sliding gap between the telescopic tool tube 3 and the tool holder 2 always maintains a slightly positive pressure state under all working conditions such as cutting, retraction, and collision avoidance. This greatly reduces the intrusion of coolant and chips into the gap due to capillary action or negative pressure, and avoids problems such as wear, jamming, or even damage to the sliding pair.

[0064] Its advantages are: no additional power source, deformation energy resource utilization: directly relying on the phase deformation of the top support plate 113 to generate extrusion force, driving the expansion airbag 13 and piston plate 142 to move, without the need for external air pumps, motors and other power components, sharing the energy generated by cutting heat with the temperature difference self-powered and the shaft stabilizing mechanism 11, realizing multi-level utilization of energy.

[0065] Uninterrupted positive pressure throughout the entire process, with protection covering all working conditions: Through the dual-stage air supply design of "flow limiting port 143 for flow stabilization + piston plate 142 for energy storage", the sliding gap maintains positive pressure under all working conditions such as cutting, tool retraction, and collision avoidance, solving the problem of protection gap in the bladder expansion and reset stage of a single air supply method.

[0066] Deeply linked with the shaft stabilizing mechanism 11, the action is completely synchronized: the operation of the chip prevention mechanism 14 is triggered by the deformation / reset of the top support plate 113 throughout the entire process, and is completely synchronized with the locking / unlocking of the shaft stabilizing mechanism 11. When the tool is machining (shaft locked), the positive pressure protection is activated, and when the tool avoids (shaft unlocked), the air is replenished and energy is stored, without any functional interference.

[0067] The structure is compact and provides multiple protections: the expansion airbag 13 is bonded between the top support plate 113, the anti-chip mechanism 14 is integrated next to the positioning ring 111, and all components are arranged in the annular gap between the tool holder 2 and the main sleeve 1, without occupying extra space, and at the same time achieving the dual functions of "axis stability + anti-chip and anti-coolant intrusion".

[0068] This section provides a specific embodiment of a temperature difference sensing mechanism 12: Component selection: Thermoelectric element: Inner diameter 8mm, outer diameter A 15mm diameter, 2mm thick miniature annular bismuth-tellurium thermoelectric element.

[0069] Supercapacitor: 2F ( (8×15mm) (Moderate capacity, smallest size, compatible with most reverse countersinks).

[0070] Voltage comparator: LM393 in SOT23-5 package (2.9×1.3×1.0mm, integrated threshold judgment + switching function).

[0071] Current limiting resistor: 0402 package (1×0.6mm) (limits the discharge current of NiTi alloy to prevent burnout).

[0072] Installation method: The hot end of the thermoelectric element is tightly attached to the outer wall of the blade holder 2 with high-temperature resistant thermally conductive silicone grease and initially fixed with high-temperature resistant double-sided thermally conductive adhesive. The cold end is naturally attached to the inner wall of the telescopic blade tube 3, and the edges are partially sealed with high-temperature resistant insulating potting compound. 0.1mm ultra-fine silver-plated wires are welded to the positive and negative poles of the thermoelectric element 121. The wires are inserted into the 0.5mm micro-groove reserved in the blade holder 2 and then welded to the reserved pads on the flexible PI micro PCB board 123 to achieve direct electrical connection with the supercapacitor.

[0073] A 10mm×20mm flexible PI micro PCB board is mounted on the rear section of the tool holder 2, and the voltage comparator and current limiting resistor are soldered onto the board.

[0074] The 2F supercapacitor is mounted on the side of the PCB board along the two circumferences of the blade, and soldered to the PCB board through the electrode pins. The whole assembly is sealed with high-temperature resistant insulating potting compound (thickness <0.5mm).

[0075] The annular gap between the tool holder 2 and the telescopic tool tube 3 retains a coolant flow space of ≥1mm. After the electronic component is packaged, its surface is flush with the tool holder 2 and does not interfere with the extension and retraction of the tool holder 2.

[0076] The wire is connected to the NiTi alloy through a 0.5mm micro groove reserved in the tool holder 2. The groove is sealed with sealant to prevent chips and coolant from entering.

[0077] This invention integrates a miniature power supply and control module in the non-cutting area of ​​the tool holder 2. This module consists of a 2F miniature cylindrical supercapacitor ( The module consists of an 8×15mm supercapacitor, an SOT23-5 packaged voltage comparator (2.9×1.3×1.0mm), and a 0402 packaged current-limiting resistor. The supercapacitor and voltage comparator are soldered onto a flexible PI micro PCB board and then attached to the inner wall. The entire module is sealed with high-temperature resistant insulating potting compound. The wires are connected to the NiTi shape memory alloy through a 0.5mm micro-groove reserved in the tool holder 2. The module is embedded in the annular gap between the tool holder 2 and the telescopic tool tube 3, occupying little space and being lightweight. It does not interfere with the elastic contraction of the tool holder 2 and the radial deformation support of the NiTi alloy. After encapsulation, it can withstand cutting vibration and coolant erosion, realizing the storage and precise triggering of thermoelectric power generation, providing a reliable drive for the phase change of NiTi alloy.

[0078] It is worth mentioning that the temperature difference sensing mechanism 12 relies on the thermoelectric element's self-generating characteristic of temperature difference, supercapacitor energy storage, and voltage comparator hardware threshold triggering pure mechanical and electrical linkage design. The entire process requires no external program, electrical control module, or manual intervention. It can achieve intermittent automatic power generation-storage-discharge cycle power supply to the top support plate 113 through the inherent physical characteristics and circuit logic of each component, which is completely synchronized with the tool cutting conditions.

[0079] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. An automatic telescopic reverse counterboring tool, characterized in that, The system includes a main sleeve (1), a knife bar (2) fixed at the center of the main sleeve (1), a telescopic knife tube (3) at one end of the main sleeve (1), the telescopic knife tube (3) being sleeved on the outer periphery of the knife bar (2), the telescopic knife tube (3) and the main sleeve (1) being in a limited sliding relationship, a fixing ring (4) fixed on the outer periphery of the knife bar (2), a telescopic spring (5) connected between the fixing ring (4) and the telescopic knife tube (3), a secondary telescopic component (6) being provided on the outer periphery of the telescopic spring (5) and being in a limited sliding relationship with the main sleeve (1), the secondary telescopic component (6) being composed of a sliding sleeve (601) and a back top seat (602), a compression spring (603) and a tenon (604) being alternately distributed between the back top seat (602) and the sliding sleeve (601). 04), the sliding sleeve (601) and the telescopic knife tube (3) are connected by a telescopic limit sliding connection. The main sleeve (1) is fixed with a constraint head (7) that restricts the movement distance of the back top seat (602). The end of the knife bar (2) is provided with a receiving groove (8). The telescopic knife tube (3) is provided with a notch near the receiving groove (8). The receiving groove (8) is rotatably connected with a central shaft (901). The outer periphery of the central shaft (901) is fixed with a knife holder (902). The knife holder (902) is detachably connected with a blade (903) on its side. The knife holder (902) is provided with a side bevel (905). The side bevel (905) is provided with a torsion spring (904) surrounding the central shaft (901) on one side.

2. The automatic telescopic reverse counterboring tool according to claim 1, characterized in that, The tool holder (2) has a curved groove near the tool holder (902). A curved block (10) adapted to the curved groove is connected to one side of the tool holder (902). A shaft stabilizing mechanism (11) is provided between the fixing ring (4) and the main sleeve (1). A temperature difference sensing mechanism (12) for providing energy is provided on the outside of the shaft stabilizing mechanism (11).

3. The automatic telescopic reverse countersinking tool according to claim 2, characterized in that, The shaft stabilizing mechanism (11) includes a positioning ring (111) fixed to the fixed ring (4) and the main sleeve (1). The positioning ring (111) is a ring structure. A movable ring (112) is provided on one side of the positioning ring (111). A top support plate (113) is connected between the inner and outer circumferences of the movable ring (112) and the positioning ring (111). The top support plate (113) is designed to fit the fixed ring (4) or the main sleeve (1) to stabilize the shaft.

4. The automatic telescopic reverse counterboring tool according to claim 3, characterized in that, The top support plate (113) has a multi-wave structure. The top support plate (113) on the inner circumference is integrally formed with a protrusion (114). The outer circumference of the fixing ring (4) is provided with multiple grooves (115) of the same size as the protrusion (114). A disc (116) for conducting current is fixed between one side of the multiple top support plates (113). The top support plate (113) can be transformed from martensitic to austenitic with higher hardness and inserted into the groove (115) under the influence of current.

5. The automatic telescopic reverse counterboring tool according to claim 4, characterized in that, The temperature difference sensing mechanism (12) includes a thermoelectric element (121), a supercapacitor (122) is connected to one side of the thermoelectric element (121), the supercapacitor (122) is connected to a flexible PI micro PCB board (123) through electrode pins, the flexible PI micro PCB board (123) is fixed inside the main sleeve (1), a voltage comparator (124) and a current limiting resistor (125) are installed on the flexible PI micro PCB board (123), and the current limiting resistor (125) is connected to the disk (116).

6. The automatic telescopic reverse counterboring tool according to claim 5, characterized in that, The cutter bar (2) is coated with a heat-insulating coating except for the curved groove and the thermoelectric element (121). The thermoelectric element (121) is attached to the outer wall of the cutter bar (2) and the inner wall of the telescopic cutter tube (3) on both sides.

7. The automatic telescopic reverse counterboring tool according to claim 6, characterized in that, An expansion airbag (13) is bonded between multiple top support plates (113), and a chip-proof mechanism (14) is provided on one side of the expansion airbag (13). Multiple micro air passages (21) are opened on the outer periphery of the tool bar (2).

8. The automatic telescopic reverse counterboring tool according to claim 7, characterized in that, The anti-chip mechanism (14) includes a piston ring (141) fixed to a positioning ring (111). A piston plate (142) is provided inside the piston ring (141). A return spring is connected between the piston plate (142) and the piston ring (141). An air outlet area (1421) and an air return area (1422) are respectively provided on both sides of the piston plate (142). A flow restrictor (143) for limiting air flow is connected between the air outlet area (1421) and the micro air passage (21). An air inlet pipe (144) is fixed between the temperature difference sensing mechanism (12) and the air outlet area (1421).

9. An automatic telescopic reverse counterboring tool according to claim 8, characterized in that, The air inlet pipe (144) is equipped with a first one-way valve (1451) that can only supply air to the air outlet area (1421). The air return area (1422) is connected to the inflatable airbag (13) by a second one-way valve (1452) that supplies air to the inflatable airbag (13). The air return area (1422) is connected to the outside by a differential pressure valve (146). The inner wall of the air return area (1422) is equipped with a limit post (147).

10. An automatic telescopic reverse counterboring tool according to any one of claims 7-9, characterized in that, The micro-air passage (21) is surrounded by a telescopic tube (15) in the area of ​​the inner circumference of the main sleeve (1), and the telescopic tube (15) is a tenon-type telescopic structure.

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