Double-head numerical control milling machine

Abstract

The application discloses a double-head numerical control milling machine tool, and relates to the technical field of numerical control milling equipment. The double-head numerical control milling machine tool is provided with air joints, air flow grooves and a plurality of elastic damping adhesion layers. The air joints and the air flow grooves are used for synchronously supplying air to each telescopic cavity, and the elastic damping adhesion layers are used for adhering to the inner wall of a workpiece. The telescopic cavity is provided with an arc-shaped adhesion supporting plate. The arc-shaped adhesion supporting plate is driven to extend radially outward, so that the elastic damping adhesion layers are tightly adhered to the inner wall of the workpiece, and multi-point supporting is formed on the inner periphery of the workpiece. An axial limiting part is arranged to limit the axial deflection of the workpiece. The elastic damping adhesion layers absorb milling vibration, reduce vibration and deformation caused by double-side cutting, and the milling cutter is fed to the front of the workpiece. The supporting plate is synchronously retracted under the action of a reset spring and exits the machining track, so that the milling cutter is prevented from damaging the elastic damping adhesion layers. After the milling hole machining is completed, the supporting plate is extended again, the supporting plate located at the machined hole is inserted into the hole to form an embedded supporting, and the supporting plate located below the next machining position continues to adhere to the inner wall of the workpiece, so that the rigidity reduction caused by continuous hole opening is compensated, and the hole position precision, contour precision and surface quality of subsequent milling holes are improved.

Description

Technical Field

[0001] This invention relates to the field of CNC milling equipment technology, specifically a double-head CNC milling machine tool. Background Technology

[0002] A double-head CNC milling machine is a CNC device that uses two milling systems to simultaneously process workpieces from both sides. It is suitable for ring-shaped workpieces, sleeve-shaped workpieces, and workpieces with circumferentially distributed milled holes. During processing, the workpiece is fitted onto the outside of the rotary fixture and positioned and clamped by an axial clamping mechanism; the rotary spindle drives the workpiece to rotate in an indexing manner, and the milling cutters on both sides sequentially process the milled holes at different positions on the circumference of the workpiece.

[0003] Existing dual-head CNC milling machines primarily fix the workpiece using a rotary clamping body and axial clamping mechanism. The inner side of the workpiece's milling section lacks a support structure that adapts to changing machining conditions. When the milling cutters on both sides machine the partially penetrated hole walls, radial cutting forces, circumferential cutting forces, and the impact from intermittent cutting are transmitted to the workpiece, causing radial vibration and axial sway. This results in deviations in the milled hole contour, hole position offsets, and chatter marks on the machined surface. As milled holes are formed sequentially, material is continuously removed from the workpiece, and the cutting load between adjacent milled holes is borne only by the remaining connecting parts. Consequently, the overall rigidity of the workpiece and the uniformity of circumferential stress decrease. The cutting forces generated by subsequent milling operations are transmitted to the already machined hole walls, causing vibration in the machined holes and further increasing the dimensional and angular errors of subsequent milled holes. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a dual-head CNC milling machine tool, which solves the problem that existing fixtures cannot switch between the inner wall support state and the retraction avoidance state according to the processing stage during continuous milling. This results in a decrease in workpiece rigidity as the number of holes increases, increased cutting vibration and hole wall deformation, and interference between the inner support component and the milling cutter's penetration trajectory, affecting hole position accuracy, contour accuracy, and machining surface quality.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a double-head CNC milling machine tool, including a rotary spindle box, an annular rotary fixture body disposed at its output end, a double-sided milling system disposed on both sides of the annular rotary fixture body, and an axial clamping mechanism coaxially disposed with the annular rotary fixture body. The annular rotary fixture body is provided with an air passage connector, an air flow groove one, a plurality of air flow groove two, and a plurality of mounting cavities disposed along the circumference. The air passage connector is connected to each air flow groove two via the air flow groove one. Each of the aforementioned mounting cavities is provided with a pneumatic telescopic support assembly. The pneumatic telescopic support assembly includes a telescopic cavity communicating with a corresponding airflow groove, a piston slidably disposed in the telescopic cavity, a telescopic support rod disposed radially, and a return spring. The two ends of the telescopic support rod are respectively connected to the piston and the arc-shaped fitting support plate, and the return spring connects the piston and the mounting cavity. The arc-shaped bonding support plate is provided with an elastic damping bonding layer facing the workpiece. When the piston is inlet into the telescopic cavity, it drives the arc-shaped bonding support plate to extend radially outward and stretch the return spring. When the telescopic cavity is venting, the return spring drives the arc-shaped bonding support plate to retract radially.

[0006] Furthermore, the dual-sided milling system includes two milling cutters arranged in opposite directions, and the axial clamping mechanism includes an axial clamping ring coaxially arranged with the annular rotary clamp body, the axial clamping ring reciprocating along the axial direction of the annular rotary clamp body.

[0007] Furthermore, there are eight mounting cavities, eight airflow slots, eight pneumatic telescopic support components, and eight arc-shaped fitting support plates. The eight mounting cavities are arranged at equal angular intervals along the circumference of the annular rotary clamp, and the eight airflow slots, eight pneumatic telescopic support components, and eight arc-shaped fitting support plates are arranged in a one-to-one correspondence.

[0008] Furthermore, the annular rotary clamp is specifically provided with a sealing cavity, and each airflow groove is located within the sealing range of the sealing cavity. A sealing strip is provided at the opening edge of the sealing cavity.

[0009] Furthermore, the telescopic cavity extends radially along the annular rotary clamp body, the inner radial end of the telescopic cavity is connected to the corresponding airflow groove, the outer radial end of the telescopic cavity is provided with a guide hole for the telescopic support rod to pass through, the piston is in a sealed sliding connection with the inner wall of the telescopic cavity, and the return spring is sleeved on the outer side of the telescopic support rod.

[0010] Furthermore, the arc-shaped bonding support plate is provided with a first axial limiting part and a second axial limiting part on both axial sides, and the elastic damping bonding layer is located between the first axial limiting part and the second axial limiting part. The elastic damping bonding layer abuts against the inner wall of the workpiece. At the position of the milled hole, the arc-shaped bonding support plate extends into the milled hole. The first axial limiting part and the second axial limiting part are respectively located on both sides of the axial direction of the milled hole. After the arc-shaped bonding support plate retracts, the arc-shaped bonding support plate, the first axial limiting part, the second axial limiting part and the elastic damping bonding layer are all spaced apart from the extension machining trajectory of the milling cutter.

[0011] Furthermore, it also includes a CNC control system, which is connected to the rotary spindle box, the double-sided milling system, the axial clamping mechanism, and the positive pressure air supply device. During the thick-wall milling stage, the CNC control system controls the positive pressure air supply device to supply air to all the telescopic cavities, so that all the arc-shaped fitting support plates extend outward synchronously. When the milling cutter reaches the retraction trigger position set by the machining program, the control system controls the milling cutter to withdraw from the workpiece and controls all the telescopic cavities to exhaust air. After all the arc-shaped fitting support plates retract, the control system controls the milling cutter to re-feed and penetrate the remaining thin-walled material of the workpiece.

[0012] Furthermore, it also includes an automatic feeding system, which is connected to the CNC control system. After the current milling hole is completed, the CNC control system controls the milling cutter to retract from the workpiece and controls all telescopic cavities to re-intake air, so that the arc-shaped fitting support plate located at the position of the milled hole extends into the milled hole, and the arc-shaped fitting support plate located below the unprocessed part abuts against the inner wall of the workpiece. The CNC control system controls the rotary spindle box to drive the workpiece to rotate indexing, and repeats the machining cycle of thick-walled support milling, arc-shaped fitting support plate retraction, thin-walled through milling, arc-shaped fitting support plate extension, and workpiece indexing in sequence.

[0013] The present invention has the following beneficial effects: This dual-head CNC milling machine supplies air synchronously to each telescopic cavity through an air connector and airflow slot one and several airflow slots two, driving the arc-shaped support plate to extend radially outward. This causes the elastic damping bonding layer to adhere tightly to the inner wall of the workpiece, forming multi-point support on the inner circumference of the workpiece. The axial limiting part restricts axial sway of the workpiece, and the elastic damping bonding layer absorbs milling vibration, reducing vibration and deformation caused by double-sided cutting. Before the milling cutter penetrates the workpiece, the support plate retracts synchronously under the action of the return spring and exits the machining trajectory, preventing the milling cutter from damaging the elastic damping bonding layer. After the milled hole is machined, the support plate extends outward again. The support plate located at the machined hole extends into the hole to form an embedded support, and the support plate located below the next machining section continues to adhere to the inner wall of the workpiece. This compensates for the decrease in stiffness caused by continuous hole opening, improves the hole position accuracy, contour accuracy, and surface quality of subsequent milled holes, and extends the service life of the elastic damping bonding layer.

[0014] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the dual-head CNC milling machine tool of the present invention; Figure 2 This is a schematic diagram of the internal structure of the dual-head CNC milling machine tool of the present invention; Figure 3 This is a schematic diagram of the overall structure of the dual-sided milling system of the present invention; Figure 4This is a schematic diagram of the overall structure of the rotary spindle box of the present invention; Figure 5 This is a schematic diagram of the internal structure of the annular rotary clamp of the present invention; Figure 6 This is a schematic diagram of the internal structure of the annular rotary clamp of the present invention from another perspective; Figure 7 This is a schematic diagram of the overall structure of the pneumatic telescopic support assembly of the present invention; Figure 8 This is a schematic diagram of the overall structure of the arc-shaped bonding support plate of the present invention.

[0016] In the diagram: 1. Double-head CNC milling machine; 101. Rotary spindle box; 102. Annular rotary fixture. 2. Dual-sided milling system; 201. Milling cutter; 3. Axial clamping mechanism; 301. Axial clamping ring; 4. Air line connector; 401. Airflow slot one; 402. Airflow slot two; 5. Sealed cavity; 6. Sealing strip; 7. Pneumatic telescopic support assembly; 701. Mounting cavity; 702. Telescopic cavity; 703. Telescopic support rod; 704. Piston; 705. Return spring; 8. Arc-shaped bonding support plate; 801. First axial limiting part; 802. Second axial limiting part; 803. Elastic damping bonding layer; 9. Automatic feeding system. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0019] Please see Figures 1-8The present invention provides a technical solution: a double-head CNC milling machine tool, including a rotary spindle box 101, an annular rotary fixture 102 disposed at its output end, a double-sided milling system 2 disposed on both sides of the annular rotary fixture 102, and an axial clamping mechanism 3 coaxially disposed with the annular rotary fixture 102. The annular rotary fixture 102 is provided with an air passage connector 4, an air flow channel 401, a plurality of air flow channels 402 and a plurality of mounting cavities 701 disposed along the circumference. The air passage connector 4 is connected to each air flow channel 402 via the air flow channel 401. Each of the mounting cavities 701 is provided with a pneumatic telescopic support assembly 7. The pneumatic telescopic support assembly 7 includes a telescopic cavity 702 that communicates with the corresponding airflow groove 402, a piston 704 that is slidably disposed in the telescopic cavity 702, a telescopic support rod 703 arranged radially, and a return spring 705. The two ends of the telescopic support rod 703 are respectively connected to the piston 704 and the arc-shaped fitting support plate 8, and the return spring 705 connects the piston 704 and the mounting cavity 701. The arc-shaped bonding support plate 8 is provided with an elastic damping bonding layer 803 facing the workpiece. When the piston 704 is inlet into the telescopic cavity 702, it drives the arc-shaped bonding support plate 8 to extend radially and stretch the return spring 705. When the telescopic cavity 702 is venting, the return spring 705 drives the arc-shaped bonding support plate 8 to retract radially. The compressed air is distributed to each airflow channel 402 through the first airflow channel 401, so that multiple pneumatic telescopic support components 7 operate synchronously. After the arc-shaped bonding support plate 8 extends radially, it forms multi-point support for the inner wall of the workpiece. The elastic damping bonding layer 803 absorbs milling vibration and limits the radial deformation of the workpiece. After the air supply stops, the return spring 705 drives the arc-shaped bonding support plate 8 to retract.

[0020] The dual-sided milling system 2 includes two milling cutters 201 arranged in opposite directions. The axial clamping mechanism 3 includes an axial clamping ring 301 arranged coaxially with the annular rotary fixture 102. The axial clamping ring 301 moves back and forth along the axial direction of the annular rotary fixture 102. The two milling cutters 201 cut from both sides of the workpiece in opposite directions, so that the cutting forces on both sides form opposing forces, reducing the unilateral radial load on the workpiece. The axial clamping ring 301 clamps the workpiece along the axial direction, restricting the axial movement of the workpiece, and transmits the rotational torque through the friction between the end face of the workpiece and the annular rotary fixture 102, thereby improving the positional symmetry of the milled holes on both sides.

[0021] The number of mounting cavities 701, airflow channels 402, pneumatic telescopic support components 7, and arc-shaped fitting support plates 8 are all eight. The eight mounting cavities 701 are arranged at equal angular intervals along the circumference of the annular rotary fixture 102. The eight airflow channels 402, the eight pneumatic telescopic support components 7, and the eight arc-shaped fitting support plates 8 are arranged in a one-to-one correspondence. The eight pneumatic telescopic support components 7 and the eight arc-shaped fitting support plates 8 are distributed at equal angular intervals along the circumference of the annular rotary fixture 102, forming a one-to-one correspondence with the eight milling hole positions of the workpiece. This ensures that the circumferential support force of the workpiece is evenly distributed, and the workpiece has corresponding support points when processed at different indexing positions, reducing processing errors caused by changes in support positions.

[0022] The annular rotary clamp body 102 is provided with a sealing cavity 5. Each airflow groove 402 is located within the sealing range of the sealing cavity 5. The opening edge of the sealing cavity 5 is provided with a sealing strip 6. The sealing cavity 5 and the sealing strip 6 form an air passage seal for the first airflow groove 401 and the second airflow groove 402, reducing the leakage of compressed air from the airflow groove connection position and keeping the air supply pressure of each telescopic cavity 702 stable.

[0023] The telescopic cavity 702 extends radially along the annular rotary clamp body 102. The radial inner end of the telescopic cavity 702 is connected to the corresponding airflow groove 402. The radial outer end of the telescopic cavity 702 is provided with a guide hole for the telescopic support rod 703 to pass through. The piston 704 is sealed and slidably connected to the inner wall of the telescopic cavity 702. The return spring 705 is sleeved on the outside of the telescopic support rod 703. The telescopic cavity 702 is arranged radially, so that the piston 704 and the telescopic support rod 703 move in a fixed direction. The guide hole restricts the radial deviation of the telescopic support rod 703. The piston 704 is sealed and slidably connected to the telescopic cavity 702 to reduce compressed air leakage. The return spring 705 is sleeved on the outside of the telescopic support rod 703 to keep the telescopic movement of the support rod and the return movement of the spring coaxial, thereby improving the movement stability of the arc-shaped fitting support plate 8.

[0024] The arc-shaped bonding support plate 8 is provided with a first axial limiting part 801 and a second axial limiting part 802 on both sides of the axial direction, and the elastic damping bonding layer 803 is located between the first axial limiting part 801 and the second axial limiting part 802. The elastic damping bonding layer 803 abuts against the inner wall of the workpiece. At the position of the milled hole, the arc-shaped bonding support plate 8 extends into the milled hole. The first axial limiting part 801 and the second axial limiting part 802 are located on both sides of the axial direction of the milled hole. After the arc-shaped bonding support plate 8 retracts, the arc-shaped bonding support plate 8, the first axial limiting part 801, the second axial limiting part 802 and the elastic damping bonding layer 803 are all spaced apart from the extension machining trajectory of the milling cutter 201. When the elastic damping bonding layer 803 abuts against the inner wall of the workpiece, it forms an inner support for the current milling position and absorbs vibration. After the arc-shaped bonding support plate 8 extends into the milled hole, it forms radial support and circumferential limiting for the milled hole, compensating for the decrease in stiffness caused by continuous opening of the workpiece. The first axial limiting part 801 and the second axial limiting part 802 restrict the axial deflection of the workpiece; after the arc-shaped bonding support plate 8 retracts, it separates from the extended machining trajectory of the milling cutter 201 to prevent the milling cutter 201 from cutting the elastic damping bonding layer 803.

[0025] It also includes a CNC control system, which is connected to the rotary spindle box 101, the double-sided milling system 2, the axial clamping mechanism 3, and the positive pressure air supply device. During the thick-wall milling stage, the CNC control system controls the positive pressure air supply device to supply air to all the telescopic cavities 702, causing all the arc-shaped support plates 8 to extend outwards synchronously. When the milling cutter 201 reaches the retraction trigger position set in the machining program, the control system controls the milling cutter 201 to retract from the workpiece and controls all the telescopic cavities 702 to exhaust air. After all the arc-shaped support plates 8 retract... The control system controls the milling cutter 201 to refeed and penetrate the remaining thin-walled material of the workpiece. The CNC control system links the feed motion of the milling cutter 201 with the extension and retraction of the pneumatic telescopic support assembly 7. When the milling cutter 201 has not penetrated the workpiece, the arc-shaped fitting support plate 8 remains extended and supports the inner wall of the workpiece. Before the milling cutter 201 penetrates the workpiece, the arc-shaped fitting support plate 8 retracts synchronously, so that the milling cutter 201 obtains penetration space. This control method takes into account both support vibration reduction and penetration avoidance, and ensures that the position of the support plate retraction remains consistent each time.

[0026] It also includes an automatic feeding system 9, which is connected to the CNC control system. After the current milling hole is completed, the CNC control system controls the milling cutter 201 to exit the workpiece and controls all the telescopic cavities 702 to re-intake air, so that the arc-shaped fitting support plate 8 located at the position of the milled hole extends into the milled hole, and the arc-shaped fitting support plate 8 located below the unprocessed part abuts against the inner wall of the workpiece. The CNC control system controls the rotary spindle box 101 to drive the workpiece to rotate indexing, and repeats the machining cycle of thick-walled support milling, arc-shaped fitting support plate 8 retraction, thin-walled through milling, arc-shaped fitting support plate 8 extension and workpiece indexing in sequence. After the current milling hole is completed, the arc-shaped fitting support plate 8 extends outward again and enters the milled hole, forming an embedded support for the milled hole. The arc-shaped fitting support plate 8 located below the next part to be processed fits against the inner wall of the workpiece, providing inner support for the next milling hole. Continuous processing is achieved through automatic feeding, workpiece indexing, and cyclic extension and retraction of the support plate, reducing the number of manual clamping operations and improving the angular consistency and processing efficiency between milled holes.

[0027] The specific workflow of this invention is as follows: First, the automatic feeding system 9 transports the workpiece to be processed to the front end of the rotary spindle box 101, so that the workpiece is sleeved on the outside of the annular rotary fixture 102. After the end face of the workpiece contacts the axial positioning surface of the annular rotary fixture 102, the axial clamping mechanism 3 drives the axial clamping ring 301 to move towards the workpiece, pressing the workpiece onto the annular rotary fixture 102. The annular rotary fixture 102 determines the rotation center of the workpiece, and the axial clamping ring 301 restricts the movement of the workpiece along the rotation axis and transmits the rotation torque through the friction between the end face of the workpiece and the axial positioning surface. After the workpiece is positioned, the automatic feeding system 9 exits the processing area. The sealing strip 6 is set at the edge of the sealing cavity 5 to isolate the sealing cavity 5 from the external milling area, preventing the cutting fluid and chips generated during the processing from entering the airflow groove 402, and sealing the airflow groove 402.

[0028] After the workpiece is clamped, the external positive pressure air supply device delivers compressed air to the airflow channel 401 through the air connector 4. The compressed air is distributed through the airflow channel 401 to multiple airflow channels 402 arranged circumferentially along the annular rotary clamp 102. Then, each airflow channel 402 simultaneously enters the telescopic cavity 702 of the corresponding pneumatic telescopic support assembly 7. The compressed air acts on the piston 704, pushing the piston 704 to move radially outward along the annular rotary clamp 102. The piston 704 drives the telescopic support rod 703 to extend outward and stretch the return spring 705. The telescopic support rod 703 pushes the arc-shaped bonding support plate 8 to move towards the inner wall of the workpiece until the elastic damping bonding layer 803 presses against the inner wall of the workpiece. Each arc-shaped bonding support plate 8 forms multiple radial supports along the inner circumference of the workpiece. The first axial limiting part 801 and the second axial limiting part 802 are located on both sides of the workpiece's axial direction, respectively, forming an axial limit on the workpiece.

[0029] After the arc-shaped bonding support plate 8 presses against the inner wall of the workpiece, the rotary spindle box 101 drives the annular rotary fixture 102, the pneumatic telescopic support assembly 7 and the workpiece to rotate synchronously, adjusting the current part to be processed to the processing position of the two end mills 201. The dual-sided milling system 2 drives the two end mills 201 to feed towards the workpiece, and performs synchronous milling on the thick wall part of the current milling hole. The arc-shaped bonding support plate 8 located below the current milling hole continues to be extended, so that the elastic damping bonding layer 803 always presses against the inner wall of the current milling part.

[0030] The cutting force generated by the milling cutter 201 is transmitted sequentially through the inner wall of the workpiece, the elastic damping bonding layer 803, the arc-shaped bonding support plate 8, the telescopic support rod 703 and the piston 704 to the annular rotary fixture 102. The arc-shaped bonding support plate 8 provides inner support for the current milling part. The elastic damping bonding layer 803 absorbs milling vibration through elastic deformation, suppressing the inward bending of the hole wall under the action of cutting force. The first axial limiting part 801 and the second axial limiting part 802 restrict the axial wobble of the current milling part, thereby improving the stability of the current thick-wall machining stage of the milled hole.

[0031] When the milling cutter 201 reaches the retraction trigger position set in the machining program, only thin-walled material remains to be penetrated in the current milled hole. The dual-sided milling system 2 pauses its feed and drives the milling cutters 201 on both sides to exit the workpiece. The external positive pressure air supply device stops supplying air, and the air connector 4 switches to the exhaust state, allowing the compressed air in each telescopic cavity 702 to be discharged sequentially through the second airflow groove 402, the first airflow groove 401, and the air connector 4. After the air pressure in the telescopic cavity 702 decreases, the return spring 705, which is in a stretched state, contracts, driving the piston 704, the telescopic support rod 703, and the arc-shaped bonding support plate 8 to retract radially inward synchronously. The elastic damping bonding layer 803 separates from the inner wall of the workpiece and exits the penetration trajectory of the milling cutter 201.

[0032] After the arc-shaped bonding support plate 8 retracts into place, a clearance gap is formed between the elastic damping bonding layer 803 and the machining trajectory of the milling cutter 201, preventing the milling cutter 201 from contacting the arc-shaped bonding support plate 8, the first axial limiting part 801, the second axial limiting part 802 and the elastic damping bonding layer 803 after penetrating the workpiece. After the pneumatic telescopic support assembly 7 completes its retraction, the axial pressing mechanism 3 continues to maintain the pressing state, and the axial pressing ring 301 presses the workpiece on the axial positioning surface of the annular rotary fixture 102. The annular rotary fixture 102 continues to determine the rotation center of the workpiece.

[0033] The dual-sided milling system 2 drives the two-sided milling cutters 201 to feed back towards the workpiece, milling away the remaining thin-walled material in the current milling hole. The two-sided milling cutters 201 form an opposing cutting action, reducing the unilateral radial load on the workpiece. After penetrating the thin wall of the workpiece, the milling cutter 201 enters the avoidance area formed by the retraction of the arc-shaped bonding support plate 8, and does not come into contact with the elastic damping bonding layer 803, thereby preventing the milling cutter 201 from cutting the elastic damping bonding layer 803 and preventing the elastic damping material from adhering to the surface of the milling cutter 201.

[0034] After the milling holes on both sides are completed, the dual-sided milling system 2 drives the milling cutters 201 on both sides to exit the workpiece, so that an indexing gap is formed between the milling cutters 201 and the workpiece. The external positive pressure air supply device re-supplied compressed air to the airflow channel 401 through the air passage connector 4. The compressed air simultaneously enters the corresponding telescopic cavity 702 through each airflow channel 402, pushing each arc-shaped bonding support plate 8 to extend radially outward. The arc-shaped bonding support plate 8 located at the corresponding position of the milled hole enters the milled hole from the inside of the workpiece, so that the elastic damping bonding layer 803 adheres to the inner edge surface of the milled hole. The first axial limiting part 801 and the second axial limiting part 802 are located on both sides of the axial direction of the milled hole, respectively, forming an axial limit for the milled hole.

[0035] The arc-shaped fitting support plate 8 provides radial support and circumferential limit for the machined milled holes, so that the machined milled holes and the annular rotary fixture 102 form an embedded fixed relationship. The arc-shaped fitting support plate 8 located below the unmachined part continues to press the inner wall of the workpiece, providing inner support for the thick-wall machining of the next set of milled holes.

[0036] After each arc-shaped bonding support plate 8 extends into place, the rotary spindle box 101 drives the annular rotary fixture 102, the arc-shaped bonding support plate 8, and the workpiece to rotate synchronously, so that the next set of parts to be processed rotates to the processing position corresponding to the milling cutters 201 on both sides. During the thick-wall processing of the next set of milling holes, the arc-shaped bonding support plate 8 that enters the milled hole bears the radial cutting force and circumferential cutting force transmitted by the workpiece. The elastic damping bonding layer 803 absorbs the vibration generated by the hole wall of the milled hole and reinforces the workpiece whose stiffness has decreased due to the opening.

[0037] Meanwhile, the arc-shaped fitting support plate 8 located below the currently milled hole remains in a fitted state, forming an inner support for the current milling part. Therefore, in the thick-wall machining stage of the next set of milled holes, the arc-shaped fitting support plate 8 in the already machined hole plays an embedded reinforcement role, and the arc-shaped fitting support plate 8 below the current machining position plays an inner wall support and vibration reduction role. When the next set of milled holes is machined to the remaining thin-walled part, the air supply is stopped again, so that all the arc-shaped fitting support plates 8 retract synchronously, the axial clamping mechanism 3 keeps the workpiece fixed, and the double-sided milling system 2 completes the through machining of the remaining thin-walled material.

[0038] After the next set of milled holes is completed, each arc-shaped support plate 8 extends out synchronously again, enters the milled hole that has been completed, and fits against the inner wall of the unprocessed part. The double-head CNC milling machine tool 1 repeats the processing cycle of "thick-wall support milling, support plate retraction, thin-wall through milling, support plate extension into the machined hole and workpiece indexing" until all the milled holes on the workpiece are completed.

[0039] After all milled holes are machined, the double-sided milling system 2 drives the two-sided milling cutters 201 to exit the workpiece, the external positive pressure air supply device stops supplying air, all arc-shaped contact support plates 8 retract under the action of the return spring 705, the rotary spindle box 101 stops rotating, the axial clamping mechanism 3 drives the axial clamping ring 301 away from the workpiece, releases the axial clamping of the workpiece, the automatic feeding system 9 enters the processing area and transports the next workpiece to be processed.

Claims

1. A double-head CNC milling machine tool, comprising a rotary spindle box (101), an annular rotary fixture (102) disposed at its output end, a double-sided milling system (2) disposed on both sides of the annular rotary fixture (102), and an axial clamping mechanism (3) coaxially disposed with the annular rotary fixture (102), characterized in that: The annular rotary clamp body (102) is provided with an air passage connector (4), an air flow groove one (401), a number of air flow groove two (402) and a number of mounting cavities (701) arranged along the circumference. The air passage connector (4) is connected to each air flow groove two (402) through the air flow groove one (401); Each of the mounting cavities (701) is provided with a pneumatic telescopic support assembly (7). The pneumatic telescopic support assembly (7) includes a telescopic cavity (702) communicating with the corresponding airflow groove (402), a piston (704) slidably disposed in the telescopic cavity (702), a telescopic support rod (703) arranged radially, and a return spring (705). The two ends of the telescopic support rod (703) are respectively connected to the piston (704) and the arc-shaped fitting support plate (8). The return spring (705) connects the piston (704) and the mounting cavity (701). The arc-shaped bonding support plate (8) is provided with an elastic damping bonding layer (803) facing the workpiece. When the piston (704) is inlet into the telescopic cavity (702), it drives the arc-shaped bonding support plate (8) to extend radially and stretch the return spring (705). When the telescopic cavity (702) is venting, the return spring (705) drives the arc-shaped bonding support plate (8) to retract radially.

2. The double-head CNC milling machine tool according to claim 1, characterized in that: The dual-sided milling system (2) includes two milling cutters (201) arranged in opposite directions. The axial clamping mechanism (3) includes an axial clamping ring (301) arranged coaxially with the annular rotary clamping body (102). The axial clamping ring (301) reciprocates along the axial direction of the annular rotary clamping body (102).

3. The double-head CNC milling machine tool according to claim 1, characterized in that: The number of the mounting cavity (701), the second airflow groove (402), the pneumatic telescopic support assembly (7) and the arc-shaped fitting support plate (8) are all eight. The eight mounting cavities (701) are arranged at equal angular intervals along the circumference of the annular rotary clamp body (102). The eight second airflow grooves (402), the eight pneumatic telescopic support assemblies (7) and the eight arc-shaped fitting support plates (8) are arranged in a one-to-one correspondence.

4. A double-head CNC milling machine tool according to claim 1, characterized in that: The annular rotary clamp (102) is provided with a sealing cavity (5), and each airflow groove (402) is located within the sealing range of the sealing cavity (5). The opening edge of the sealing cavity (5) is provided with a sealing strip (6).

5. A double-head CNC milling machine tool according to claim 1, characterized in that: The telescopic cavity (702) extends radially along the annular rotary clamp body (102). The inner radial end of the telescopic cavity (702) is connected to the corresponding airflow groove (402). The outer radial end of the telescopic cavity (702) is provided with a guide hole for the telescopic support rod (703) to pass through. The piston (704) is in a sealed sliding connection with the inner wall of the telescopic cavity (702). The reset spring (705) is sleeved on the outside of the telescopic support rod (703).

6. A double-head CNC milling machine tool according to claim 5, characterized in that: The arc-shaped bonding support plate (8) has a first axial limiting part (801) and a second axial limiting part (802) on both sides of the axial direction, and the elastic damping bonding layer (803) is located between the first axial limiting part (801) and the second axial limiting part (802). The elastic damping bonding layer (803) abuts against the inner wall of the workpiece. At the position of the milled hole, the arc-shaped bonding support plate (8) extends into the milled hole. The first axial limiting part (801) and the second axial limiting part (802) are located on both sides of the axial direction of the milled hole. After the arc-shaped bonding support plate (8) retracts, the arc-shaped bonding support plate (8), the first axial limiting part (801), the second axial limiting part (802) and the elastic damping bonding layer (803) are all spaced apart from the extension machining trajectory of the milling cutter (201).

7. A double-head CNC milling machine tool according to claim 6, characterized in that: It also includes a CNC control system, which is connected to the rotary spindle box (101), the double-sided milling system (2), the axial clamping mechanism (3) and the positive pressure air supply device respectively. During the thick-wall milling stage, the CNC control system controls the positive pressure air supply device to supply air to all the telescopic cavities (702) so that all the arc-shaped fitting support plates (8) extend outward synchronously. When the milling cutter (201) reaches the retraction trigger position set by the machining program, the milling cutter (201) is controlled to withdraw from the workpiece and all the telescopic cavities (702) are controlled to exhaust air. After all the arc-shaped fitting support plates (8) retract, the milling cutter (201) is controlled to re-feed and penetrate the remaining thin-wall material of the workpiece.

8. A double-head CNC milling machine tool according to claim 7, characterized in that: It also includes an automatic feeding system (9), which is connected to the CNC control system. After the current milling hole is completed, the CNC control system controls the milling cutter (201) to exit the workpiece and controls all the telescopic cavities (702) to re-intake air, so that the arc-shaped fitting support plate (8) located at the position of the milled hole extends into the milled hole, so that the arc-shaped fitting support plate (8) located below the unprocessed part abuts against the inner wall of the workpiece. The CNC control system controls the rotary spindle box (101) to drive the workpiece to rotate by indexing, and repeats the machining cycle of thick wall support milling, arc-shaped fitting support plate (8) retraction, thin wall through milling, arc-shaped fitting support plate (8) extension and workpiece indexing in sequence.

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