Blanking method and die for sensor diaphragm

Abstract

The invention discloses a blanking method and die for a sensor diaphragm, and relates to the technical field of sensor diaphragm machining, and the blanking method for the sensor diaphragm comprises the following steps: before a to-be-cut plate is blanked, pretreatment is firstly carried out; the to-be-cut plate comprises a blanking area and a fixing area, and the pretreatment method comprises the steps that the fixing area of the to-be-cut plate is fixed, and the blanking area of the to-be-cut plate generates vibration. The blanking die comprises a male die used for blanking a to-be-cut plate and a restraining part used for bearing the to-be-cut plate, a blank holder used for pressing the to-be-cut plate is arranged above the restraining part, the restraining part and the blank holder are each provided with a through hole allowing the male die to penetrate through, and the inner diameter size of each through hole is matched with the outer diameter size of the male die. The male die is matched with the restraining piece to cut the to-be-cut plate; a vibration source enabling the blanking area of the to-be-cut plate to generate vibration is arranged below the restraining piece. Before blanking, the strain rate sensitivity of the to-be-cut plate is reduced through vibration, the initial residual stress is eliminated, and the blanking yield is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sensor diaphragm processing, in particular to a punching method and a die for a sensor diaphragm. Background Art

[0002] The diaphragm cutting process achieves material separation by making the relative displacement between the punch and the blank holder reach a set value, so that the stress in the edge area of ​​the diaphragm exceeds the fracture strength of the material. In the prior art, the sheet to be cut is placed on a flexible lower die, and then a punching machine is used to simultaneously complete the forming and cutting of the diaphragm in a one-time forming process.

[0003] However, for materials with high strain rate sensitivity (such as metals and their alloys), the strain rate increases sharply due to high-speed shear deformation during the blanking process, and the thermal activation process of dislocation slip inside the material is suppressed. At the same time, the dynamic dislocation proliferation and entanglement effect are intensified, thereby inducing strong work hardening behavior. Although this hardening mechanism can increase the local flow stress, it also enhances the ductility of the material, causing the fracture mode to change from ideal brittle cleavage to ductile fracture. Specifically, when the blanking edge cuts into the sheet, the high strain rate sensitivity causes the crack tip plastic zone to expand at a lower rate, and the crack expansion path deviates from the pure shear surface, forming a tear ligament and a fibrous fracture, and finally producing a rough fracture surface and burrs, resulting in quality problems such as reduced surface finish of the blanking section and uncontrolled dimensional tolerances.

[0004] At the same time, since the initial residual stress inside the sheet has not been pre-treated, these residual stresses will be superimposed on the external loading stress during the blanking process, resulting in a significant change in the stress distribution inside the diaphragm after cutting. This uneven stress distribution will interfere with the elastic recovery behavior of the diaphragm, making it difficult to accurately control the springback process, thereby affecting the geometric accuracy and dimensional stability of the diaphragm. Summary of the invention

[0005] The purpose of the present invention is to provide a punching method and mold for a sensor diaphragm to solve the problems existing in the above-mentioned prior art. The diaphragm is pretreated before punching to eliminate initial residual stress, avoid edge wrinkling, and improve the yield of the diaphragm.

[0006] To achieve the above object, the present invention provides the following solutions: A method for punching a sensor diaphragm, before punching a sheet to be punched, pretreatment is first performed; the sheet to be punched includes a punching area and a fixing area, and the pretreatment method is to fix the fixing area of ​​the sheet to be punched and vibrate the punching area of ​​the sheet to be punched, thereby reducing the strain rate sensitivity of the sheet to be punched and eliminating the initial residual stress.

[0007] In an exemplary embodiment, ultrasonic waves are used to vibrate the blanking area of ​​the blank to be cut.

[0008] In an exemplary embodiment, when the material of the sheet to be cut is metal, an alternating magnetic field is used to vibrate the punching area of ​​the sheet to be cut. The sheet to be cut is in the alternating magnetic field, and the changing magnetic field induces eddy currents in the sheet to be cut. The eddy currents interact with the magnetic field to generate force, causing the sheet to vibrate.

[0009] In an exemplary embodiment, the failure number N of the sheet to be cut is obtained based on the stress-life curve obtained from the material fatigue test, the frequency of the AC power supply of the alternating magnetic field is ω, and the vibration duration is between 0.1N / ω and 0.3N / ω.

[0010] The present invention also provides a sensor diaphragm punching die, comprising a punch for punching a sheet to be cut and a restraining member for supporting the sheet to be cut, a pressure ring for pressing the sheet to be cut is arranged above the restraining member, and both the restraining member and the pressure ring are provided with a through hole for the punch to pass through, and the inner diameter of the through hole is adapted to the outer diameter of the punch, and the punch cooperates with the restraining member to cut the sheet to be cut; the area of ​​the sheet to be cut that is pressed by the pressure ring and the restraining member is a fixed area, and the area corresponding to the through hole is a punching area; a vibration source is arranged below the restraining member to cause the punching area of ​​the sheet to be cut to vibrate.

[0011] In an exemplary embodiment, a bottom plate is disposed below the restraining member, an elastic member for returning the restraining member to its original position is disposed between the restraining member and the bottom plate, and the elastic member is disposed around the through hole.

[0012] In an exemplary embodiment, a flexible lower mold is also provided on the base plate, and the flexible lower mold extends upward into the through hole of the restraint member; a molding pattern is provided on the lower surface of the punch, and the flexible lower mold cooperates with the punch to perform stamping and forming in the punching area of ​​the sheet to be cut.

[0013] In an exemplary embodiment, the vibration source is an alternating magnetic field generator, and the alternating magnetic field generator includes an excitation coil, a capacitor, and a sliding resistor connected in series.

[0014] In an exemplary embodiment, the excitation coil is a circular coil wound by a square cross-section wire with a side length of a, 0.01D≤a≤0.1D, D is the diameter of the punching area, the number of turns is n, 1≤n≤5; the inner diameter of the coil is d, and 0.5d+n*a=0.5D. The distribution of the electromagnetic force generated by the excitation coil in series with the AC power supply is simulated to ensure that the sheet to be cut is subjected to unidirectional electromagnetic force and the maximum value is close to the center of the punching area, so that the stress at the junction of the punching area and the fixed area is maximized; if the result shows that the electromagnetic force does not meet the requirements, d is increased until the requirements are met and the inductance of the excitation coil is determined to be L.

[0015] In an exemplary embodiment, the resistance R of the sliding rheostat is adjusted, the maximum stress at the junction of the fixed area and the blanking area of ​​the sheet to be cut obtained in the electromagnetic structure coupling analysis simulation is σ, and the yield strength of the sheet to be cut is σ s ,σ / σ s =x, then R=0.9 / x.

[0016] Compared with the prior art, the present invention has achieved the following technical effects: Before blanking the sheet to be cut, pretreatment is performed. By generating mechanical vibration in the blanking area, cyclic load is used to induce controllable micro-damage (such as dislocation cell structure reorganization, microcrack initiation and subgrain boundary slip) inside the material, especially at the junction of the fixed area and the blanking area, which can effectively reduce its strain rate sensitivity. The core mechanism is that the micro-defect network induced by vibration will significantly shorten the mean free path of dislocations, inhibit dynamic dislocation proliferation and long-range slip, and cause the thermally activated deformation mechanism of the material (such as dislocation climb and cross slip) to be blocked. In this state, the strain rate sensitivity index value decreases, and the deformation behavior of the material changes from rate-dependent to rate-insensitive. Specifically, in the subsequent high-speed shearing process, the pre-existing micro-damage acts as a stress concentration source, preferentially triggers the nucleation of cleavage cracks (Griffith crack theory), and at the same time, the micro-defect network hinders the expansion of the plastic zone at the crack tip, so that the fracture mode changes from ductile fracture dominated by hole aggregation to brittle fracture dominated by cleavage. This transformation can effectively inhibit the necking phenomenon and reduce the formation of tear ligaments, thereby obtaining a smooth shear surface and precise geometric contour (dimensional tolerance is controlled at IT7-IT8 level), which is especially suitable for high-precision cutting process optimization of low stacking fault energy metals.

[0017] At the same time, vibration can also eliminate the initial residual stress of the sheet to be cut, effectively homogenize the stress distribution inside the sheet, reduce the superposition effect of the initial residual stress and the external loading stress during the punching process, and thus significantly improve the stress state of the diaphragm after cutting. This stress homogenization helps stabilize the elastic recovery behavior of the diaphragm, improve the control accuracy of the springback process, and ensure the geometric accuracy and dimensional stability of the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic structural diagram of a sensor diaphragm punching die disclosed in a specific embodiment of the present invention; Figure 2 Design process diagram for blanking die; Figure 3 is a circuit diagram of an alternating magnetic field generator; Among them, 1. Punch; 2. Pressure ring; 3. Sheet material to be cut; 4. Constraint; 5. Flexible lower die; 6. Elastic part; 7. Vibration source. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. People familiar with the technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The purpose of the present invention is to provide a punching method and mold for a sensor diaphragm to solve the problems existing in the prior art, pre-treat the diaphragm before punching, eliminate initial residual stress, avoid edge wrinkling, and improve the yield of the diaphragm.

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Embodiment 1 Please refer to Figure 1 This embodiment provides a method for punching a sensor diaphragm. Before punching the sheet material 3 to be punched, pretreatment is performed first. The sheet material 3 to be punched includes a punching area and a fixing area. The pretreatment method is to fix the fixing area of ​​the sheet material 3 to be punched and vibrate the punching area of ​​the sheet material 3 to be punched to eliminate the initial residual stress.

[0024] The working principle of this embodiment is as follows: before blanking the sheet 3 to be cut, pretreatment is first performed, and mechanical vibration is generated in the blanking area, and cyclic load is used to induce controllable micro-damage (such as dislocation cell structure reorganization, microcrack initiation and subgrain boundary slip) inside the material, especially at the junction of the fixed area and the blanking area, so as to effectively reduce its strain rate sensitivity. Its core mechanism is that the micro-defect network induced by vibration will significantly shorten the mean free path of dislocations, inhibit dynamic dislocation proliferation and long-range slip, and cause the thermally activated deformation mechanism of the material (such as dislocation climb and cross slip) to be blocked. In this state, the strain rate sensitivity index value decreases, and the deformation behavior of the material changes from rate-dependent to rate-insensitive. Specifically, in the subsequent high-speed shearing process, the pre-existing micro-damage acts as a stress concentration source, preferentially triggers the nucleation of cleavage cracks (Griffith crack theory), and at the same time, the micro-defect network hinders the expansion of the plastic zone at the crack tip, so that the fracture mode changes from ductile fracture dominated by hole aggregation to brittle fracture dominated by cleavage. This transformation can effectively inhibit the necking phenomenon and reduce the formation of tear ligaments, thereby obtaining a smooth shear surface and precise geometric contour (dimensional tolerance is controlled at IT7-IT8 level), which is especially suitable for high-precision cutting process optimization of low stacking fault energy metals.

[0025] At the same time, the initial residual stress of the sheet 3 to be cut can be eliminated through vibration, which can effectively homogenize the stress distribution inside the sheet, reduce the superposition effect of the initial residual stress and the external loading stress during the punching process, and thus significantly improve the stress state of the diaphragm after cutting. This stress homogenization helps to stabilize the elastic recovery behavior of the diaphragm, improve the control accuracy of the springback process, and ensure the geometric accuracy and dimensional stability of the diaphragm.

[0026] Specifically, the vibration source 7 that causes the punching area of ​​the sheet 3 to be cut to vibrate can be an ultrasonic wave or an alternating magnetic field. Among them, for non-metallic materials, such as organic materials, ultrasonic waves are used to vibrate the punching area of ​​the sheet 3 to be cut; for metal materials, such as 316L, etc., an alternating magnetic field is used to vibrate the punching area of ​​the sheet 3 to be cut. The principle is that the sheet 3 to be cut is in an alternating magnetic field, and the changing magnetic field induces eddy currents in the sheet 3 to be cut. The interaction between the eddy currents and the magnetic field generates a Lorentz force (electromagnetic force), which causes the sheet 3 to be cut to vibrate. The frequency of the ultrasonic wave and the alternating magnetic field must be adapted to the natural frequency of the sheet 3 to be cut. Regarding the vibration duration, the number of failures N of the sheet to be cut is obtained based on the stress-life curve obtained from the material fatigue test. The frequency of the AC power supply of the alternating magnetic field is ω, and the vibration duration is between 0.1N / ω and 0.3N / ω.

[0027] Embodiment 2 Please refer to Figures 1 to 3The present embodiment provides a sensor diaphragm blanking die, comprising a punch 1 for blanking a sheet material 3 to be blanked and a constraint 4 for carrying the sheet material 3 to be blanked, a blank holder 2 for pressing the sheet material 3 to be blanked is arranged above the constraint 4, both the constraint 4 and the blank holder 2 are provided with a through hole for the punch 1 to pass through, the inner diameter of the through hole is adapted to the outer diameter of the punch 1, and the punch 1 and the constraint 4 cooperate to cut the sheet material 3 to be blanked; the area where the sheet material 3 to be blanked is pressed by the blank holder 2 and the constraint 4 is a fixed area, and the area corresponding to the through hole is a blanking area; a vibration source 7 for vibrating the blanking area of ​​the sheet material 3 to be blanked is arranged below the constraint 4. A bottom plate is arranged below the constraint 4, and an elastic member 6 for returning the constraint 4 is arranged between the constraint 4 and the bottom plate, and the elastic member 6 is arranged around the through hole. A flexible lower mold 5 is also provided on the bottom plate, and a molding pattern is provided on the lower surface of the punch 1. The flexible lower mold 5 cooperates with the punch 1 to perform stamping and molding in the punching area of ​​the sheet material 3 to be cut to form a specific texture or pattern. The flexible lower mold 5 extends upward into the through hole of the restraint part 4, so that the elastic part 6 arranged around the through hole also surrounds the flexible lower mold 5.

[0028] In the initial state of stamping, the vertical direction from top to bottom is: punch 1, blank holder 2, sheet material 3 to be cut, constraint 4, flexible lower die 5, bottom plate, vibration source 7. The sheet material 3 to be cut is placed on the upper surface of the constraint 4, and a groove for accommodating the sheet material 3 to be cut can be provided on the upper surface of the constraint 4 to position the sheet material 3 to be cut. When the sheet material 3 to be cut is placed in the groove, the upper surface of the sheet material 3 to be cut needs to protrude from the groove.

[0029] During stamping, firstly, the blank holder 2 is controlled to move downward to contact the sheet material 3 to be cut on the upper surface of the constraint 4, and then the constraint 4 is driven downward by a distance d0 to ensure that the edge of the sheet material 3 to be cut is fixed during pretreatment. d0=F 反 *0.9 / x / k / K, where F 反 is the radial constraint reaction force of the fixed boundary of the electromagnetic structure simulation result, K is the total stiffness of the elastic part 6, k is the static friction coefficient between the sheet and the die, the maximum stress at the junction of the fixed area and the blanking area of ​​the sheet to be cut obtained in the electromagnetic structure coupling analysis simulation is σ, the resistance value in the simulation is unit resistance, and the yield strength of the sheet to be cut is σ s , then x=σ / σ s .

[0030] In this embodiment, the vibration source 7 is an alternating magnetic field generator, which includes an excitation coil, a capacitor, a sliding resistor, an AC power supply, a control switch, etc. connected in series.

[0031] After the sheet material 3 to be cut is stabilized under the fixation of the pressure ring 2 and the constraint 4, through reasonable design of the excitation coil and circuit control, the punching area of ​​the sheet material 3 to be cut is vibrated at a specific frequency by the electromagnetic force when the fixed area is fixed and constrained, and the residual stress inside the sheet material 3 to be cut is released and damage begins to accumulate on the edge.

[0032] After the vibration ends, the blank holder 2 continues to drive the sheet material 3 to be cut downward until the sheet material 3 to be cut contacts the flexible lower die 5 extending into the through hole of the restraining member 4 .

[0033] Then, the blank holder 2 and the restraining member 4 are kept stationary, and the punch 1 is moved downward to form the sheet and cut off the diaphragm.

[0034] In order to ensure that the die does not deform during the stamping process, the punch 1, the blank holder 2, the constraint 4, the elastic member 6, and the bottom plate must all be made of suitable materials, such as heat-treated die steel. Under the premise of ensuring strength, the top plate of the shell of the magnetic field generator can be directly used as the bottom plate.

[0035] Please refer to the blanking die design process Figure 2 , the specific design process of each parameter is as follows: 1. Excitation coil and circuit control design Coil design: An axisymmetric circular excitation coil is used, which is wound with a square cross-section wire with a side length of a. The value range of a is 0.01D≤a≤0.1D, where D is the diameter of the finished diaphragm, which is actually the diameter of the punching area. The number of coil turns n is in the range of 1≤n≤5, and the inner diameter d of the coil satisfies the constraint condition 0.5d+n*a=0.5D. The electromagnetic force distribution generated by the excitation coil in series with the AC power supply on the sheet 3 to be cut is simulated to ensure that the sheet 3 to be cut is subjected to unidirectional electromagnetic force and the maximum value is close to the center of the punching area, so that the stress at the junction of the punching area and the fixed area is maximized. If the result shows that the electromagnetic force does not meet the requirements, increase d until it meets the requirements, and determine the inductance L of the excitation coil.

[0036] Circuit Design: Please refer to the circuit diagram of the alternating magnetic field generator Figure 3 .

[0037] The excitation coil is connected in series with the AC power supply, and the matching capacitor C is calculated according to the AC frequency ω. .

[0038] The circuit resistance R is adjusted by sliding the rheostat. The maximum stress at the junction of the fixed area and the blanking area of ​​the sheet to be cut obtained in the electromagnetic structure coupling analysis simulation is σ. The resistance value in the simulation is unit resistance, and the yield strength of the sheet to be cut is σ s ,σ / σ s=x, then R=0.9 / x. A magnetic flux concentrator may be provided between the excitation coil and the sheet material 3 to be cut to enhance the electromagnetic coupling effect.

[0039] 2. Diaphragm vibration preprocessing analysis Material property acquisition: The mechanical property parameters of the material are determined by tension and compression tests, and the stress-life curve of the sheet material 3 to be cut can be obtained by fatigue tests.

[0040] Stress control: Set the sliding rheostat to make the maximum stress at the edge of the diaphragm reach 0.9σ s .

[0041] 3. Structural design of punch 1 and blank holder 2 The outer diameter of the punch of the punch 1 is D, and the inner diameter of the through hole of the blank holder 2 is close to the outer diameter of the punch 1, and the value range is D to 1.02D to ensure that the die gap is minimized. The outer diameter of the blank holder 2 is greater than the side length 2D of the square sheet, and the bottom plate or the top plate of the housing of the magnetic field generator is consistent with the outer diameter of the blank holder 2 to achieve structural unity.

[0042] 4. Design of the size of the restraint 4 Geometric parameters: Through simulation analysis, the position difference d1 between the blank holder 2 and the punch 1 during cutting is determined, and the minimum thickness of the constraint 4 is 3d1. The inner diameter of the through hole of the constraint 4 is close to the outer diameter of the punch 1, and the value range is D to 1.02D to ensure that the mold gap is minimized. The outer diameter of the constraint 4 is consistent with the outer diameter of the blank holder 2.

[0043] After the sheet material 3 to be cut contacts the flexible lower die 5 extending to the inside of the through hole of the restraint part 4, the flexible lower die 5 will be deformed under the action of the punch 1 during the downward cutting process of the punch 1. During the deformation of the flexible lower die 5, its outer wall will contact the inner wall of the through hole of the restraint part 4. The inner diameter of the through hole of the restraint part 4 and the thickness of the restraint part 4 can restrain the radial deformation of the flexible lower die 5, so that the flexible lower die 5 has stronger elastic restoring force in the axial direction, and cooperates with the punch 1 to realize stamping forming of the blanking area.

[0044] 5. Elastic parts 6 system design Arrangement and quantity: The elastic member 6 in this embodiment is a spring, and multiple springs are evenly distributed on the same circumference, with a quantity of 4 to 6, to achieve uniform force distribution.

[0045] Spring parameters: Through the simulation analysis in step 2, it is determined that the blank holder force required for the vibration of the sheet 3 to be cut is F1, and the blank holder force required for forming is determined to be F2 through stamping simulation. The blank holder force provided by the spring is F3=max{F1, F2}. The weight M of the constraint 4 is calculated based on the size and material density. The total stiffness K and compressibility of the spring must ensure that the maximum force can be provided>F3+M; the spring setting space is limited by the difference in the inner and outer diameters of the constraint 4, so the maximum outer diameter of the spring is determined; the spring height should be greater than 3d1+A+d0, where A is the pre-processed vibration amplitude of the sheet 3 to be cut; based on the above design requirements, the pitch, cross-sectional shape and size, inner diameter, and height of the spring are comprehensively determined.

[0046] 6. Flexible lower mold 5 design Geometric parameters: The thickness of the flexible lower die 5 is the sum of the thickness of the constraint 4 and the remaining height of the spring after being compressed.

[0047] Material hardness: The lower die hardness ranges from 80A to 100A to ensure sufficient elastic recovery force to optimize the diaphragm molding quality.

[0048] The above design optimizes the key parameters of the excitation coil, circuit control, punch 1, blank holder 2, constraint 4, spring system and flexible lower die 5 through multi-physics field simulation and mechanical analysis, ensuring the accuracy, stability and reliability of the diaphragm cutting and molding process.

[0049] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third" and the like are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0050] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by one-piece molding using a casting process) (except when it is obviously impossible to use an one-piece molding process).

[0052] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any technical solution disclosed in the present invention include states or shapes that are approximate, similar, or close thereto.

[0053] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0054] It should be noted that the structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0055] It should also be noted that in the embodiments of the present application, the same figure mark is used to represent the same component or the same part.

[0056] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0057] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0058] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for punching a sensor diaphragm, characterized in that: Before blanking the sheet to be cut, pretreatment is performed first; the sheet to be cut includes a blanking area and a fixing area, and the pretreatment method is to fix the fixing area of ​​the sheet to be cut and vibrate the blanking area of ​​the sheet to be cut to reduce the strain rate sensitivity of the sheet to be cut and eliminate the initial residual stress.

2. The method for punching a sensor diaphragm according to claim 1, characterized in that: Ultrasonic waves are used to vibrate the blanking area of ​​the sheet to be cut.

3. The punching method of the sensor diaphragm according to claim 1, characterized in that: When the material of the sheet to be cut is metal, an alternating magnetic field is used to vibrate the punching area of ​​the sheet to be cut. The sheet to be cut is in the alternating magnetic field, and the changing magnetic field induces eddy currents in the sheet to be cut. The eddy currents interact with the magnetic field to generate force, causing the sheet to vibrate.

4. The method for punching a sensor diaphragm according to claim 3, characterized in that: According to the stress-life curve obtained from the material fatigue test, the failure number N of the sheet to be cut is obtained, the frequency of the AC power supply of the alternating magnetic field is ω, and the vibration duration is between 0.1N / ω and 0.3N / ω.

5. A sensor diaphragm punching die, characterized in that: It includes a punch for punching a sheet to be cut and a restraining member for carrying the sheet to be cut, a pressure ring for pressing the sheet to be cut is arranged above the restraining member, and the restraining member and the pressure ring are both provided with a through hole for the punch to pass through, the inner diameter of the through hole is adapted to the outer diameter of the punch, and the punch cooperates with the restraining member to cut the sheet to be cut; the area of ​​the sheet to be cut pressed by the pressure ring and the restraining member is a fixed area, and the area corresponding to the through hole is a punching area; a vibration source is arranged below the restraining member to vibrate the punching area of ​​the sheet to be cut.

6. The sensor diaphragm punching die according to claim 5, characterized in that: A bottom plate is arranged below the restraining member, an elastic member for returning the restraining member to its original position is arranged between the restraining member and the bottom plate, and the elastic member is arranged around the through hole.

7. The sensor diaphragm punching die according to claim 6, characterized in that: A flexible lower die is also provided on the bottom plate, and the flexible lower die extends upward into the through hole of the restraint member; a molding pattern is provided on the lower surface of the punch, and the flexible lower die cooperates with the punch to perform stamping and molding in the punching area of ​​the sheet to be cut.

8. The sensor diaphragm punching die according to claim 5, characterized in that: The vibration source is an alternating magnetic field generator, which includes an excitation coil, a capacitor, and a sliding resistor connected in series.

9. The sensor diaphragm punching die according to claim 8, characterized in that: The excitation coil is a circular coil wound by a square cross-section wire with a side length of a, 0.01D≤a≤0.1D, D is the diameter of the punching area, the number of turns is n, 1≤n≤5; the inner diameter of the coil is d, and 0.5d+n*a=0.5D. The electromagnetic force distribution generated by the excitation coil in series with the AC power supply is simulated to ensure that the sheet to be cut is subjected to unidirectional electromagnetic force and the maximum value is close to the center of the punching area, so that the stress at the junction of the punching area and the fixed area is maximized; if the result shows that the electromagnetic force does not meet the requirements, d is increased until the requirements are met and the inductance of the excitation coil is determined to be L.

10. The sensor diaphragm punching die according to claim 8, characterized in that: Adjust the resistance R of the sliding rheostat. The maximum stress at the junction of the fixed area and the blanking area of ​​the sheet to be cut obtained in the electromagnetic structure coupling analysis simulation is σ, and the yield strength of the sheet to be cut is σ s ,σ / σ s =x, then R=0.9 / x.

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