Numerical control punch and clamp tooling thereof

Abstract

The present application relates to a kind of numerical control punch and its clamp tooling, including punch workstation and for installing forming die clamp tooling, clamp tooling is installed between punch workstation and forming die, clamp tooling is used as the coupling interface of mould and machine tool, clamp tooling includes base body, the clamping groove being opened in the upper end of base body, the lower die of being arranged in clamping groove, the connecting seat being arranged in the bottom of base body, buffer damping component is arranged on the lower die;The present application is connected by buffer damping component, spherical self-aligning component, and high-frequency impact load and eccentric load moment are buffered, buffer damping component directly buffers downward impact, so that the load transmitted to aligning component becomes quasi-static smooth pressure, while the connection of spherical self-aligning component, the adaptive deflection of mould is facilitated, further buffers eccentric load moment, and the processing of asymmetric forming is facilitated, and practicality is improved.

Description

Technical Field

[0001] This invention relates to the field of CNC punching machine technology, specifically to a CNC punching machine and its fixture. Background Technology

[0002] In the integral plastic forming of metal sheets (such as deep drawing, flanging, bulging, etc.), the fixture of CNC punching machines serves as the coupling interface between the forming mold and the machine tool table. Its performance directly determines the forming quality and equipment life. Since plastic forming parts are often geometrically asymmetrical, the center of the forming force is seriously deviated from the geometric center of the mold, generating a huge overturning moment. If the fixture base cannot adaptively compensate for this moment, it will lead to quality problems such as mold tilting, unilateral wear of the guide plate, and uneven wall thickness of the parts. At the same time, if the hundred-ton-level high-frequency impact load generated during the stamping is directly transmitted to the connection interface between the base and the worktable, it will cause fretting wear of the connecting pair and bolt loosening, resulting in dynamic drift of the installation reference. For example, patent number CN114669645B discloses a fixture base for CNC punching machines, which absorbs impact energy through the spring between the base plate and the functional block, as well as the hollow box-piston buffer mechanism set in the base, and has the function of automatically ejecting the workpiece.

[0003] First, existing punch press fixtures do not consider the overturning problem under asymmetrical forming conditions. The fixture base and the punch press table are still rigidly connected, which cannot adaptively compensate for the overturning moment. This causes the die to tilt dynamically during the loading stroke, resulting in uneven distribution of the forming cavity gap, which directly affects the uniformity of the wall thickness and dimensional accuracy of the parts. Based on this, we propose a CNC punch press and its fixture to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a CNC punch press and its fixture, which, through impact isolation and self-alignment, buffers impacts while adapting to asymmetric forming processes, thus solving the problem of overturning under eccentric loads in existing fixtures that do not consider asymmetric forming conditions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a CNC punch press and its fixture, comprising a punch press worktable and a fixture for mounting a forming mold, the fixture being installed between the punch press worktable and the forming mold, the fixture serving as a coupling interface between the mold and the machine tool; The fixture includes a base body, a clamping groove on the upper end of the base body, a lower mold in the clamping groove, and a connecting seat at the bottom of the base body. The lower mold is equipped with a buffer and shock absorption component, which is used to isolate the transmission of forming impact load to the base body. A spherical self-aligning component is provided between the upper end of the connecting seat and the bottom of the base body. The spherical self-aligning assembly includes a convex ball connector and a concave ball fixing seat that cooperate with each other. The spherical self-aligning assembly is used to adaptively compensate for the tilt angle of the base body under eccentric load. A reset buffer assembly is provided circumferentially on the outer side of the spherical self-aligning assembly at the bottom of the base body. The reset buffer assembly is used to provide a restoring torque to make the base body return to the center. A circumferential limiting assembly is provided at the edge of the lower end face of the base body. The circumferential limiting assembly is used to limit the circumferential rotational freedom of the base body.

[0006] It should be noted that the lower end of the connecting seat is fixedly connected to the punch press table via a prestressed tie rod assembly or a hydraulic zero-point positioning unit. The prestressed tie rod assembly is evenly distributed circumferentially and applies a constant axial preload to eliminate the microscopic gap between the connecting seat and the punch press table, ensuring the axial stiffness of the forming force transmission path. When a hydraulic zero-point positioning unit is used, the bottom of the connecting seat is equipped with a matching pull stud interface to achieve second-level quick change and micron-level repeatable positioning accuracy of the mold interface.

[0007] Furthermore, the buffer and shock absorption assembly includes multiple mounting slots opened at the bottom of the inner side of the clamping slot, a hydraulic damper installed in the mounting slot, and a buffer spring sleeved on the outside of the hydraulic damper. The multiple mounting slots are arranged in an array. The upper end of the hydraulic damper is connected to the lower end of the lower mold, and the upper and lower sides of the buffer spring abut against the bottom of the clamping slot and the lower end of the lower mold, respectively.

[0008] It is important to note that the damping coefficient of the hydraulic damper and the stiffness of the buffer spring are matched to ensure that the natural frequency of the buffer shock absorption component is far away from the main frequency band of the stamping impact, thus avoiding the resonance amplification effect. The preload is set to more than 1.2 times the maximum forming impact force to ensure that the buffer spring is always in a compressed state during the impact unloading stage, preventing the lower die from separating and impacting the bottom of the clamping groove.

[0009] Furthermore, the lower mold integrates a pneumatic auxiliary ejection mechanism, which includes an ejector plate slidably installed at the bottom of the forming cavity of the lower mold, an airbag column set at the lower end of the ejector plate, and a pressure storage cavity set at the lower end of the lower mold. The multiple airbag columns are distributed at equal intervals, and the bottoms of the multiple airbag columns are connected to the pressure storage cavity through airflow channels. When the mold is closed and stamping is performed, the ejector plate is pressed down and compresses the airbag column, and the gas is forced into the pressure storage cavity for storage. After the mold is opened and the pressure is released, the high-pressure gas in the pressure storage cavity flows back to the airbag column, driving the ejector plate to pop up to assist the workpiece demolding.

[0010] It is important to note that the ratio of the volume of the pressure storage chamber to the total compression volume of the airbag column is set to 3:1-5:1 to ensure that the pressure inside the pressure storage chamber is still more than 0.3MPa higher than atmospheric pressure after the final energy storage, so as to ensure that the ejector plate has sufficient initial acceleration when the mold is opened. The airbag column is made of oil-resistant and pressure-resistant polyurethane elastomer.

[0011] Furthermore, the upper end of the convex ball connector is fixedly connected to the lower end of the base body, the upper end of the concave ball fixing seat is provided with a spherical groove, the lower end of the convex ball connector is slidably fitted in the spherical groove, the lower end of the concave ball fixing seat is fixedly connected to the connecting seat, the inner wall of the spherical groove is provided with annularly distributed hydraulic chambers, the interior of the concave ball fixing seat is provided with an oil passage connected to the hydraulic chambers, and the lower end of the base body is provided with a circumferential seal outside the convex ball connector, the lower end of the circumferential seal abuts against the upper end face of the concave ball fixing seat to seal the upper opening gap of the spherical groove.

[0012] It is important to note that the spherical mating pair between the convex ball joint and the concave ball fixing seat is lubricated with synthetic lubricating oil. The lubricating oil has excellent extreme pressure anti-wear properties and viscosity-temperature stability, and can maintain a complete elastic fluid dynamic pressure oil film under contact stress of hundreds of tons, preventing spherical wear and jamming caused by boundary friction. At the same time, the radius of curvature of the spherical pair is set to 2.53 times the height of the base body. While ensuring a self-aligning angle of ±1°2°, the eccentricity is minimized to the maximum extent, thereby geometrically reducing the overturning instability moment arm.

[0013] Furthermore, the circumferential seal is an annular wear-resistant sealing ring, and the contact pressure between the circumferential seal and the upper end face of the concave ball fixing seat is greater than the maximum working oil pressure in the oil pressure chamber.

[0014] It should be noted that the circumferential seal has a stepped or lip-shaped cross-section with its lip facing the inside of the hydraulic chamber. It utilizes the self-tightening effect of hydraulic pressure to enhance the sealing reliability. The seal material is a polytetrafluoroethylene composite material, which has both a low coefficient of friction and high wear resistance, ensuring that the sealing surface does not experience abnormal wear during the frequent tilting and straightening process of the base body.

[0015] Furthermore, the reset buffer assembly includes multiple hydraulic damping cylinders evenly distributed along the circumference of the base body. The telescopic ends of the hydraulic damping cylinders are fixedly connected to the base body. The cylinder body of the hydraulic damping cylinder and the connecting seat are fixedly connected. An outer plate is fixedly installed on the upper end of the connecting seat outside the hydraulic damping cylinder. A constant pressure oil tank is provided on the outer wall of the outer plate.

[0016] Furthermore, the connecting seat is equipped with a proportional directional valve assembly. The constant pressure oil tank is pre-filled with high-pressure hydraulic oil. The oil inlet of the proportional directional valve assembly is connected to the constant pressure oil tank. The oil outlet of the proportional directional valve assembly is connected to multiple hydraulic damping cylinders and oil passages through branch lines. When the base body is in a horizontal state, the proportional directional valve assembly remains in the neutral closed position. When the base body is tilted, the hydraulic damping cylinder on the tilted side is compressed to generate a displacement signal or pressure feedback, triggering the proportional directional valve assembly to switch to the corresponding working position, so that the high-pressure hydraulic oil in the constant pressure oil tank is actively injected into the oil pressure chamber on that side for forced lubrication.

[0017] It should be noted that the lubrication logic is a forced lubrication mode. The pre-charge pressure of the constant pressure oil tank is set to 1.5-2 times the minimum pressure required for the spherical pair to form a complete elastic hydrodynamic oil film. The triggering method of the proportional directional valve group can be any one or a combination of mechanical or electronic tilt sensor triggering. The hydraulic damping cylinder extended on the opposite side receives oil replenishment through another working position of the proportional directional valve group to avoid cavitation and imbalance of reset torque caused by negative pressure suction.

[0018] Furthermore, a filter screen is installed at one end of the inner side of the constant pressure oil tank, and a cooling coil is installed at the other end of the inner side of the constant pressure oil tank. The constant pressure oil tanks are connected in series on the oil return path of the oil pressure chamber for filtering and cooling the lubricating oil.

[0019] It is important to note that the filter screen has a filtration accuracy of 10μm-25μm to intercept metal particles generated by spherical wear and external dust. The heat exchange area of ​​the cooling coil is designed to match the stamping cycle and the oil temperature rise rate, so that the working temperature of the lubricating oil is kept stable in the range of 40℃-60℃, avoiding viscosity reduction and oil film rupture due to excessive oil temperature. A back pressure valve is also installed on the oil return path to maintain a return oil back pressure of 0.2MPa-0.5MPa, preventing cavitation in the return oil pipeline and constant pressure oil tank, and ensuring continuous and stable flow in the lubrication circuit.

[0020] Furthermore, four circumferential limiting components are distributed in a circumferential ring array. Each circumferential limiting component includes an anti-rotation pin fixedly installed at the lower edge of the base body and a limiting groove opened at the upper edge of the concave ball fixing seat. The lower end of the anti-rotation pin is fixedly connected to a wear-resistant ball head, which slides in the limiting groove. The arc trajectory of the limiting groove is concentric with the self-aligning trajectory of the spherical self-aligning component. The circumferential limiting components are used to constrain the circumferential rotational degree of freedom without interfering with the tilt compensation motion.

[0021] It is important to note that the radius of the arc-shaped trajectory of the limiting groove is equal to the distance from the center of curvature of the spherical pair to the axis of the anti-rotation pin, ensuring that the wear-resistant ball head always slides along the tangent direction of the limiting groove under any self-aligning angle of the base body, without generating additional radial constraint force. The surface of the wear-resistant ball head is nitrided, and the inner wall of the limiting groove is inlaid with a self-lubricating copper bushing.

[0022] A CNC punch press includes a machine body and a punch press worktable mounted on the machine body. A fixture is installed on the punch press worktable, and a forming die is coupled to the punch press worktable through the fixture.

[0023] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. This invention buffers high-frequency impact loads and off-center torques by connecting a buffer and shock-absorbing component and a spherical self-aligning component in series. The buffer and shock-absorbing component directly buffers the downward impact, making the load transmitted to the self-aligning component a quasi-static stable pressure. At the same time, the connection of the spherical self-aligning component facilitates the adaptive deflection of the mold, further buffering the off-center torque, which is convenient for asymmetric molding and improves practicality. 2. This invention uses a constant pressure oil storage tank as an independent pressure source and a tilt-triggered proportional directional valve group as a distribution hub. At the same time as the tilt occurs, the corresponding oil is injected into the oil pressure chamber, thereby establishing sufficient oil film pressure to achieve elastic fluid dynamic pressure lubrication, ensuring the lubrication effect of the spherical structure. At the same time, the constant pressure oil storage tank filters and cools the lubricating oil to avoid friction causing the lubricating oil temperature to be too high. 3. This invention couples the ejection function with the stamping process timing, using the stamping energy during mold closing to compress the air bladder column to store energy, and automatically releases the drive ejection plate when the mold opens, which facilitates demolding and ejection. 4. The present invention achieves circumferential constraint through a circumferential limiting component. The anti-rotation pin slides radially in the limiting groove to form a circumferential limit, so that the base body will not deflect in direction when tilted, thereby ensuring the molding accuracy when tilted and reset. Attached Figure Description

[0024] Figure 1 The diagram shown is a schematic representation of the overall internal structure of the present invention. Figure 2 The diagram shown is a three-dimensional structural schematic of the present invention; Figure 3 The diagram shown is a schematic representation of the internal structure of the base body of this invention. Figure 4 The diagram shown is a schematic representation of the connector structure of the present invention. Figure 5 The diagram shown is a schematic representation of the internal structure of the concave ball fixing seat of the present invention. Figure 6 The diagram shown is a top view of the clamping groove structure of the present invention; Figure 7 The diagram shown is a top view of the concave ball fixing base of the present invention. Figure 8 The diagram shown is a schematic representation of the internal structure of the constant pressure oil storage tank of the present invention. Figure 9 The diagram shown is a schematic of the punch press worktable structure of the present invention.

[0025] Explanation of reference numerals in the attached drawings: 1. Punch press worktable; 2. Base body; 21. Hydraulic damping cylinder; 22. Outer plate; 23. Constant pressure oil tank; 231. Filter screen; 232. Cooling coil; 24. Proportional directional valve assembly; 3. Clamping slot; 31. Mounting slot; 32. Hydraulic damper; 33. Buffer spring; 4. Lower die; 41. Ejector plate; 42. Airbag column; 43. Pressure storage chamber; 5. Connecting seat; 6. Convex ball joint; 7. Concave ball fixing seat; 71. Hydraulic chamber; 72. Oil passage one; 8. Anti-rotation pin; 81. Wear-resistant ball head; 9. Limiting groove. Detailed Implementation

[0026] 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.

[0027] Please see Figures 1-8 This embodiment of a CNC punch press and its fixture includes a punch press worktable 1 and a fixture for mounting a forming die. The fixture is installed between the punch press worktable 1 and the forming die, and serves as a coupling interface between the die and the machine tool. The fixture includes a base body 2, a clamping groove 3 on the upper end of the base body 2, a lower die 4 disposed in the clamping groove 3, and a connecting seat 5 disposed at the bottom of the base body 2. The lower die 4 is provided with a buffer and shock absorption assembly, which is used to isolate the transmission of forming impact load to the base body 2. The connecting seat... A spherical self-aligning assembly is provided between the upper end of 5 and the bottom of the base body 2; the spherical self-aligning assembly includes a convex ball connector 6 and a concave ball fixing seat 7 that cooperate with each other. The spherical self-aligning assembly is used to adaptively compensate the tilt angle of the base body 2 under the action of eccentric load; a reset buffer assembly is provided circumferentially on the outside of the spherical self-aligning assembly at the bottom of the base body 2. The reset buffer assembly is used to provide a restoring torque to make the base body 2 return to the center. A circumferential limiting assembly is provided at the edge of the lower end face of the base body 2. The circumferential limiting assembly is used to limit the circumferential rotational freedom of the base body 2.

[0028] It should be noted that the base body 2 and the punch press worktable 1 are rigidly fixedly connected. During punch press operation, the impact force is buffered by the buffer and shock absorption components, reducing the impact force on the base body 2 and avoiding the impact on the connection during cyclic operation. At the same time, the deflection of the spherical self-aligning component facilitates the tilting of the base body 2, making it easy to adapt to the forming and processing of asymmetrical workpieces, achieving adaptive adjustment and improving practicality.

[0029] Please see Figure 1 , Figure 3, Figure 6 In this embodiment, the buffer and shock absorption assembly includes multiple mounting slots 31 formed at the bottom of the inner side of the clamping slot 3, a hydraulic damper 32 installed in the mounting slot 31, and a buffer spring 33 sleeved on the outside of the hydraulic damper 32. The multiple mounting slots 31 are arranged in an array. The upper end of the hydraulic damper 32 is connected to the lower end of the lower mold 4. The upper and lower sides of the buffer spring 33 abut against the bottom of the clamping slot 3 and the lower end of the lower mold 4, respectively.

[0030] It should be noted that the damping coefficient of the hydraulic damper 32 and the stiffness of the buffer spring 33 are designed to be matched. The impact force is buffered by the hydraulic damper 32, reducing the impact force on the tooling connection.

[0031] In this embodiment, another implementation of the buffer and shock absorption component uses a disc spring damping composite module to replace the separate structure of the hydraulic damper 32 and the buffer spring 33. The module is coaxially assembled from multiple sets of stacked disc springs and a viscoelastic damping spindle embedded in the inner ring of the disc spring. It has both high load-bearing stiffness and high-frequency energy absorption characteristics, and is suitable for stamping conditions with larger tonnage and faster cycle time.

[0032] In this embodiment, a pneumatic auxiliary ejection mechanism is integrated inside the lower mold 4. The pneumatic auxiliary ejection mechanism includes an ejector plate 41 slidably installed at the bottom of the forming cavity of the lower mold 4, an airbag column 42 disposed at the lower end of the ejector plate 41, and a pressure storage cavity 43 disposed at the lower end of the lower mold 4. The multiple airbag columns 42 are distributed at equal intervals, and the bottoms of the multiple airbag columns 42 are connected to the pressure storage cavity 43 through airflow channels. When the mold is closed and stamping is performed, the ejector plate 41 is pressed down and compresses the airbag column 42. The gas is forced into the pressure storage cavity 43 for storage. After the mold is opened and the pressure is released, the high-pressure gas in the pressure storage cavity 43 flows back to the airbag column 42, driving the ejector plate 41 to pop up to assist the workpiece demolding.

[0033] It should be noted that the connection between the pressure storage chamber 43 and the air bladder column 42 means that under high pressure, the air bladder column 42 is compressed, thereby maintaining high pressure in the pressure storage chamber 43. During discharge, the pressure drives the ejector plate 41 to reset, forming an ejection.

[0034] Please see Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 7In this embodiment, the upper end of the convex ball connector 6 is fixedly connected to the lower end of the base body 2. The upper end of the concave ball fixing seat 7 is provided with a spherical groove. The lower end of the convex ball connector 6 is slidably fitted in the spherical groove. The lower end of the concave ball fixing seat 7 is fixedly connected to the connecting seat 5. The inner wall of the spherical groove is provided with annularly distributed hydraulic chambers 71. The interior of the concave ball fixing seat 7 is provided with an oil passage 72 that communicates with the hydraulic chambers 71. The lower end of the base body 2 is provided with a circumferential seal outside the convex ball connector 6. The lower end of the circumferential seal abuts against the upper end face of the concave ball fixing seat 7 to seal the upper opening gap of the spherical groove. The circumferential seal is an annular wear-resistant sealing ring. The contact pressure between the circumferential seal and the upper end face of the concave ball fixing seat 7 is greater than the maximum working oil pressure in the hydraulic chamber 71.

[0035] It should be noted that the convex ball connector 6 and the concave ball fixing seat 7 rotate at multiple angles. In the forming process of asymmetrical workpieces, the mold can form an adaptive tilt according to the different thicknesses on both sides of the workpiece. When tilted, the circumferential seal abuts against the spherical groove to seal it and prevent lubrication from overflowing. The cross-sectional shape of the circumferential seal is a lip structure, with the lip facing the inside of the hydraulic chamber 71. The self-tightening effect of the hydraulic pressure enhances the sealing reliability.

[0036] Please see Figure 1 , Figure 4 , Figure 5 , Figure 8 In this embodiment, the reset buffer assembly includes multiple hydraulic damping cylinders 21 evenly spaced along the circumference of the base body 2. The telescopic ends of the hydraulic damping cylinders 21 are fixedly connected to the base body 2. The cylinder body of the hydraulic damping cylinder 21 is fixedly connected to the connecting seat 5. An outer plate 22 is fixedly installed on the upper end of the connecting seat 5 outside the hydraulic damping cylinder 21. A constant pressure oil tank 23 is provided on the outer wall of the outer plate 22. A proportional directional valve group 24 is provided inside the connecting seat 5. The constant pressure oil tank 23 is pre-filled with high-pressure hydraulic oil. The oil inlet of the proportional directional valve group 24 is connected to the constant pressure oil tank 23. The oil outlet of the proportional directional valve group 24 is connected to the branch circuit and the multiple hydraulic damping cylinders respectively. The 21 and oil passage 72 are connected. When the base body 2 is in a horizontal state, the proportional directional valve group 24 remains in the neutral closed position. When the base body 2 tilts, the hydraulic damping cylinder 21 on the tilted side is compressed to generate a displacement signal or pressure feedback, triggering the proportional directional valve group 24 to switch to the corresponding working position, so that the high pressure hydraulic oil in the constant pressure oil tank 23 is actively injected into the oil pressure chamber 71 on that side for forced lubrication. A filter screen 231 is provided at one end of the inner side of the constant pressure oil tank 23, and a cooling coil 232 is provided at the other end of the inner side of the constant pressure oil tank 23. The constant pressure oil tank 23 is connected in series on the oil return path of the oil pressure chamber 71 for filtering and cooling the lubricating oil.

[0037] It should be noted that the pre-charge pressure of the constant pressure oil tank 23 is set to 1.5-2 times the minimum pressure required for the spherical pair to form a complete elastic hydrodynamic oil film. The filter screen 231 and the cooling coil 232 can filter and cool the lubricating oil, avoiding the mixing of impurities in the lubricating oil and the generation of high temperature during friction, which would lead to lubricating oil failure. In addition, the multiple hydraulic damping cylinders 21 are interconnected, and the outer plate 22 has interconnected flow channels inside, which are connected to the multiple hydraulic damping cylinders 21.

[0038] In this embodiment, another implementation of the proportional directional valve group 24 uses an electrically controlled tilt sensor in conjunction with a PLC to control the electromagnetic proportional valve. The tilt sensor collects the attitude data of the base body 2 in real time, and the PLC adjusts the valve opening proportionally according to the tilt angle and the rate of change, so as to realize continuous stepless adjustment of lubrication flow and reset torque, which is compatible with a more intelligent CNC punching machine system.

[0039] Please see Figure 1 , Figure 5 In this embodiment, four circumferential limiting components are distributed in a circumferential ring array. Each circumferential limiting component includes an anti-rotation pin 8 fixedly installed at the lower edge of the base body 2 and a limiting groove 9 opened at the upper edge of the concave ball fixing seat 7. The lower end of the anti-rotation pin 8 is fixedly connected to a wear-resistant ball head 81, which slides in the limiting groove 9. The arc trajectory of the limiting groove 9 is concentric with the self-aligning trajectory of the spherical self-aligning component. The circumferential limiting components are used to constrain the circumferential rotational degree of freedom without interfering with the tilt compensation motion.

[0040] It should be noted that the radius of the arc-shaped trajectory of the limiting groove 9 is equal to the distance from the center of curvature of the spherical pair to the axis of the anti-rotation pin 8, ensuring that the wear-resistant ball head 81 of the base body 2 always slides along the tangent direction of the limiting groove 9 under any self-aligning angle, without generating additional radial constraint force.

[0041] The working principle of the above embodiments is as follows: During the stamping loading stage, the upper die descends and closes with the lower die 4. The forming impact force first acts on the buffer and shock absorption components. The hydraulic damper 32 and the buffer spring 33 jointly absorb the high-frequency impact energy, causing the peak load transmitted to the base body 2 to attenuate. This transforms the stress state of the connection interface from high-frequency impact to a quasi-static stable load, fundamentally blocking the causes of fretting wear and bolt loosening, and ensuring the long-term dynamic stability of the installation reference. When machining asymmetrical parts, the center of the forming force deviates from the geometric center of the die, generating an overturning moment. Under the action of the moment, the base body 2 rotates slightly around the center of the spherical self-aligning component. The convex ball connector 6 adaptively deflects within the spherical groove of the concave ball fixing seat 7, compensating for the tilt angle, so that the die axis follows the slider movement axis in real time, ensuring a uniform circumferential distribution of the convex and concave die clearance. At the same time, the tilt side... The hydraulic damping cylinder 21 is compressed, and the resulting displacement signal or pressure feedback triggers the proportional directional valve group 24 to switch to the corresponding working position. The high-pressure hydraulic oil in the constant pressure oil tank 23 is actively injected into the oil pressure chamber 71 on this side to form forced elastic fluid dynamic pressure lubrication. After the lubricating oil flows out of the oil pressure chamber 71, it enters the constant pressure oil tank 23 through the return oil path. It is filtered by the filter screen 231 and cooled by the cooling coil 232 in sequence to form a closed-loop active lubrication-reset linkage circuit. When the stamping is completed and the mold is opened, the upper mold moves upward to release pressure, the buffer and shock absorption components release the stored elastic potential energy, and the auxiliary base body 2 quickly returns to the center. At the same time, the high-pressure gas stored in the pressure storage chamber 43 flows back to the airbag column 42, driving the ejector plate 41 to pop up and automatically eject the formed workpiece from the forming cavity of the lower mold 4, realizing assisted demolding without the need for an external power source.

[0042] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A CNC punch press and its fixture, comprising a punch press worktable (1) and a fixture for mounting forming dies, characterized in that: The fixture is installed between the punch press worktable (1) and the forming die. The fixture is used as a coupling interface between the die and the machine tool. The fixture includes a base body (2), a clamping groove (3) opened on the upper end of the base body (2), a lower mold (4) set in the clamping groove (3), and a connecting seat (5) set at the bottom of the base body (2). A buffer and shock absorption component is provided on the lower mold (4). The buffer and shock absorption component is used to isolate the transmission of molding impact load to the base body (2). A spherical self-aligning component is provided between the upper end of the connecting seat (5) and the bottom of the base body (2). The spherical self-aligning assembly includes a convex ball connector (6) and a concave ball fixing seat (7) that cooperate with each other. The spherical self-aligning assembly is used to adaptively compensate the tilt angle of the base body (2) under eccentric load. The bottom of the base body (2) is provided with a reset buffer assembly on the outer side of the spherical self-aligning assembly. The reset buffer assembly is used to provide a restoring torque to make the base body (2) return to center. A circumferential limiting assembly is provided at the edge of the lower end face of the base body (2). The circumferential limiting assembly is used to limit the circumferential rotational freedom of the base body (2).

2. The CNC punching machine and its fixture according to claim 1, characterized in that: The buffer and shock absorption assembly includes multiple mounting slots (31) opened at the bottom of the inner side of the clamping slot (3), a hydraulic damper (32) installed in the mounting slot (31), and a buffer spring (33) sleeved on the outside of the hydraulic damper (32). The multiple mounting slots (31) are arranged in an array. The upper end of the hydraulic damper (32) is connected to the lower end of the lower mold (4). The upper and lower sides of the buffer spring (33) abut against the bottom of the clamping slot (3) and the lower end of the lower mold (4), respectively.

3. A CNC punching machine and its fixture according to claim 1, characterized in that: The lower mold (4) integrates a pneumatic auxiliary ejection mechanism. The pneumatic auxiliary ejection mechanism includes an ejector plate (41) that is slidably installed at the bottom of the forming cavity of the lower mold (4), an airbag column (42) set at the lower end of the ejector plate (41), and a pressure storage cavity (43) set at the lower end of the lower mold (4). Multiple airbag columns (42) are distributed at equal intervals, and the bottom of multiple airbag columns (42) is connected to the pressure storage cavity (43) through an airflow channel. When the mold is closed and stamped, the ejector plate (41) is pressed down and compresses the airbag column (42). The gas is pressed into the pressure storage cavity (43) for storage. After the mold is opened and the pressure is released, the high-pressure gas in the pressure storage cavity (43) flows back to the airbag column (42) and drives the ejector plate (41) to pop up to assist the workpiece demolding.

4. A CNC punching machine and its fixture according to claim 1, characterized in that: The upper end of the convex ball connector (6) is fixedly connected to the lower end of the base body (2). The upper end of the concave ball fixing seat (7) is provided with a spherical groove. The lower end of the convex ball connector (6) is slidably fitted in the spherical groove. The lower end of the concave ball fixing seat (7) is fixedly connected to the connecting seat (5). The inner wall of the spherical groove is provided with annularly distributed oil pressure chambers (71). The interior of the concave ball fixing seat (7) is provided with an oil passage (72) connected to the oil pressure chambers (71). The lower end of the base body (2) is located outside the convex ball connector (6) and is provided with a circumferential seal. The lower end of the circumferential seal abuts against the upper end face of the concave ball fixing seat (7) to seal the upper opening gap of the spherical groove.

5. A CNC punching machine and its fixture according to claim 4, characterized in that: The circumferential seal is an annular wear-resistant seal ring. The contact pressure between the circumferential seal and the upper end face of the concave ball fixing seat (7) is greater than the maximum working oil pressure in the oil pressure chamber (71).

6. A CNC punching machine and its fixture according to claim 5, characterized in that: The reset buffer assembly includes multiple hydraulic damping cylinders (21) evenly distributed along the circumference of the base body (2). The telescopic end of the hydraulic damping cylinder (21) is fixedly connected to the base body (2). The cylinder body of the hydraulic damping cylinder (21) and the connecting seat (5) are fixedly connected. The upper end of the connecting seat (5) is located outside the hydraulic damping cylinder (21) and a peripheral plate (22) is fixedly installed. A constant pressure oil tank (23) is provided on the outer wall of the peripheral plate (22).

7. A CNC punching machine and its fixture according to claim 6, characterized in that: The connecting seat (5) is equipped with a proportional directional valve group (24). The constant pressure oil tank (23) is pre-filled with high pressure hydraulic oil. The oil inlet of the proportional directional valve group (24) is connected to the constant pressure oil tank (23). The oil outlet of the proportional directional valve group (24) is connected to a branch and multiple hydraulic damping cylinders (21) and oil passage channel 1 (72). When the base body (2) is in a horizontal state, the proportional directional valve group (24) remains in the neutral closed position. When the base body (2) is tilted, the hydraulic damping cylinder (21) on the tilted side is compressed to generate a displacement signal or pressure feedback, triggering the proportional directional valve group (24) to switch to the corresponding working position, so that the high pressure hydraulic oil in the constant pressure oil tank (23) is actively injected into the oil pressure chamber (71) on that side for forced lubrication.

8. A CNC punching machine and its fixture according to claim 7, characterized in that: A filter screen (231) is provided at one end of the inner side of the constant pressure oil storage tank (23), and a cooling coil (232) is provided at the other end of the inner side of the constant pressure oil storage tank (23). The constant pressure oil storage tank (23) is connected in series on the oil return path of the oil pressure chamber (71) for filtering and cooling the lubricating oil.

9. A CNC punching machine and its fixture according to claim 8, characterized in that: Four circumferential limiting components are distributed in a circumferential ring array. Each circumferential limiting component includes an anti-rotation pin (8) fixedly installed at the lower edge of the base body (2) and a limiting groove (9) opened at the upper edge of the concave ball fixing seat (7). The lower end of the anti-rotation pin (8) is fixedly connected to a wear-resistant ball head (81). The wear-resistant ball head (81) slides in the limiting groove (9). The arc trajectory of the limiting groove (9) is concentric with the self-aligning trajectory of the spherical self-aligning component. The circumferential limiting components are used to constrain the circumferential rotational degree of freedom without interfering with the tilt compensation motion.

10. A CNC punch press, comprising a machine body and a punch press worktable (1) disposed on the machine body, characterized in that, The punch press worktable (1) is equipped with a fixture as described in any one of claims 1-9, and the forming mold is coupled to the punch press worktable (1) through the fixture.

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