A bottom hole forming method for high-strength steel plate

Abstract

The invention discloses a bottom hole forming method applied to a high-strength steel plate. Firstly, a convex punch and a convex die are used to punch a material to make the material convex; then, a forming punch, a forming die and a forming top core are used to punch the convex part of the material, the forming top core is arranged in the inner hole of the forming die, and a circle of bosses is arranged on the top of the forming top core. Under the action of the bosses on the top surface of the forming top core in the forming die, the material between the forming top core and the punch is squeezed to make the material flow to the outside and inside of the bosses, so that the material fills the forming die; then, a punching punch and a punching die are used to punch the forming part of the material to form a preliminary bottom hole on the material; then, a shaping punch and a shaping die are used to shape the preliminary bottom hole on the material; finally, the bottom of the bottom hole on the material is chamfered.

Description

Technical Field

[0001] The invention belongs to the technical field of metal punching, and in particular relates to a bottom hole forming method applied to a high-strength steel plate. Background Art

[0002] like Figure 1-3 As shown, it is a fixing bracket for car locks, made of SPFC590, with a material thickness of 2.0mm. The difficulty of this product lies in the M8 bottom hole forming part. The inner diameter of the bottom hole requires tapping, the inner diameter requires Ф6.7m, the outer diameter requires Ф9.7mm, the height requires 6.0±0.1mm, and the bottom surface of the product's flange requires a flatness of 0.2.

[0003] The locks must be precise, without misalignment or abnormal noise. To ensure the dimensions of the drawings are qualified, the wall thickness of the M8 bottom hole must be qualified and uniform. If the conventional flanging method is used, the pre-punching and then flanging, the flanging height will not meet the requirements. For 2.0mm thick high-strength steel plate materials, the pre-punching punch has a small diameter and a short lifespan, and the rear end face of the flanging is prone to cracking. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a bottom hole forming method for high-strength steel plates.

[0005] The present invention is achieved through the following technical solutions:

[0006] A bottom hole forming method for high-strength steel plate comprises the following steps:

[0007] Step 1, using a convex punch and a convex die to punch the material to make the material convex;

[0008] Step 2, punching the convex part of the material in step 1 by using a forming punch, a forming die, and a forming top core;

[0009] The molding top core is arranged in the inner hole of the molding die, a circle of bosses is arranged on the top of the molding top core, the top portion of the molding top core outside the bosses is divided into an outer top surface, the outer top surface is a plane, when the molding top core is at the lower limit position, the height position of the outer top surface of the molding top core is just the terminal position of the bottom hole of the material to be made; the top surface portion of the molding top core inside the boss is a circular area, the circular area is milled to make the bottom surface height of the circular area smaller than the height of the outer top surface;

[0010] The forming punch presses downward the convex part of the material in step 1, and under the action of the boss on the top surface of the forming top core in the forming die, the material between the forming top core and the forming punch is squeezed, so that the material flows to the outside and inside of the boss, so that the material fills the forming die, and the circular area accommodates the excess material squeezed to the inside of the boss;

[0011] Step 3, using a punching punch and a punching die to punch the formed part of the material processed in step 2 to form a preliminary bottom hole on the material;

[0012] Step 4, shaping the preliminary bottom hole on the material processed in step 3 using a shaping punch and a shaping die to eliminate the punching residual in step 3;

[0013] Step 5, chamfering the bottom of the bottom hole on the material processed in step 4.

[0014] In the above technical solution, the active end of the embossing punch is hemispherical, and the embossing die has an inner hole corresponding to the embossing punch. The embossing punch punches toward the inner hole of the embossing die, so that the punched material forms an arc-shaped embossment in the inner hole of the embossing die.

[0015] In the above technical solution, a supporting core is also arranged in the inner hole of the embossing die, and a return spring is arranged at the bottom of the supporting core. The supporting core can be used to push the embossed part of the material out of the embossing die after the material is stamped and embossed.

[0016] In the above technical solution, the boss is drafted, the draft angle is 45°-55°, and the boss height is 1.0mm.

[0017] In the above technical solution, the effective action end of the forming punch includes a cylindrical section and a chamfered section above the cylindrical section.

[0018] In the above technical solution, the radial gap between the cylindrical section of the forming punch and the inner hole of the forming die is smaller than the material thickness, so that the effect of material thinning can be eliminated by extrusion.

[0019] In the above technical solution, the inner hole of the punching die is a stepped hole, including an upper hole section and a lower hole section. The diameter of the upper hole section is 0.1 mm larger than the outer diameter of the forming part of the material after processing in step 2, so that it can be placed in the upper hole section of the punching die; the shearing clearance between the punch and the lower hole section of the punching die is 0.05 mm, ensuring a sufficient bright band.

[0020] In the above technical solution, the gap between the shaping punch and the shaping die is given to be 1.5mm, and a supporting core is also arranged in the inner hole of the shaping die. A reset spring is arranged at the bottom of the supporting core, and the supporting core is used to push the bottom hole after shaping out of the shaping die.

[0021] In the above technical scheme, a pressing plate, a chamfering sleeve and a chamfering insert are used to chamfer the bottom of the bottom hole on the material processed in step 4. The pressing plate is used to press the material against the chamfering sleeve. The chamfering insert is embedded in the chamfering sleeve. The top of the chamfering insert is provided with an effective action end for chamfering the bottom of the bottom hole of the material. The effective action end includes a first cylindrical section and a chamfering bevel section located below the first cylindrical section. The diameter of the chamfering bevel section gradually increases from top to bottom. Below the chamfering bevel section is the main body section of the chamfering insert. The diameter of the main body section is greater than the maximum diameter of the chamfering bevel section.

[0022] In the above technical solution, a push rod is vertically provided in the chamfering sleeve, and the bottom end of the push rod is connected to a return spring, so that the chamfered material is pushed upward out of the chamfering sleeve by the push rod.

[0023] The advantages and beneficial effects of the present invention are:

[0024] The method of the present invention can well perform drilling on high-strength steel plates, and the bottom holes produced have a large height, which can be more than 6 mm, and the bottom holes produced have uniform thickness, high strength, and are not easy to crack. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a fixing bracket of a car lock.

[0026] Figure 2 It is a side view of a fixing bracket of a car lock.

[0027] Figure 3 It is a cross-sectional view of a bottom hole on a fixing bracket of a car lock.

[0028] Figure 4 It is a schematic diagram of the processing state of step 1 of the bottom hole forming method of the present invention.

[0029] Figure 5 It is a schematic diagram of the processing state of step 2 of the bottom hole forming method of the present invention.

[0030] Figure 6 It is an enlarged schematic diagram of the top of the forming top core used in step 2 of the present invention.

[0031] Figure 7 It is a top plan view of the forming top core used in step 2 of the present invention.

[0032] Figure 8 It is a schematic diagram of the processing state of step three of the bottom hole forming method of the present invention.

[0033] Fig. 9 It is a schematic diagram of the processing state of step four of the bottom hole forming method of the present invention.

[0034] Fig.10 It is a schematic diagram of the processing state of step five of the bottom hole forming method of the present invention.

[0035] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with specific embodiments.

[0037] A bottom hole forming method for high-strength steel plate comprises the following steps:

[0038] Step 1: Use the convex punch 1 and the convex die 2 to punch the material 3 to make the material convex. Figure 4 , the thickness of the material is 2mm, the action end 1.1 of the embossing punch 1 is hemispherical with a radius of 6mm, the embossing die has an inner hole corresponding to the embossing punch, and the embossing punch punches the inner hole of the embossing die, so that the punched material forms an arc-shaped embossment in the inner hole of the embossing die. Furthermore, a core 4 is also provided in the inner hole of the embossing die, and a reset spring 5 is provided at the bottom of the core, so that the core can be used to push the embossed part of the material out of the embossing die after the material is embossed by punching.

[0039] Step 2, using the forming punch 6, the forming die 7, and the forming top core 8 to punch the convex part of the material in step 1, so that the convex part of the material is formed. Figure 5-7 The effective end of the forming punch 6 includes a cylindrical section 6.1 and a chamfered section 6.2 above the cylindrical section. The cylindrical section 6.1 is used to press and stretch the convex part of the material downward so that the convex part of the material is stretched into an inner hole of equal diameter. The chamfered section 6.2 is used to chamfer the top of the inner hole of the material.

[0040] The molding top core 8 is arranged in the inner hole of the molding die 7. When the molding top core 8 reaches the lower limit position, the height position of the top of the molding top core 8 is exactly the terminal position of the material bottom hole to be made. A circle of bosses 8.1 is arranged on the top of the molding top core 8. The bosses are used for drafting. The draft angle is about 50°. After testing, 51° is the best. The boss height is 1.0mm. The top surface of the molding top core 8 outside the boss 8.1 is named as the outer top surface 8.3. The outer top surface 8.3 is a plane. When the molding top core 8 reaches the lower limit position, the height position of the top of the molding top core 8 is exactly the terminal position of the material bottom hole to be made. That is, the height position of the outer top surface 8.3 of the molding top core 8 is exactly the terminal position of the material bottom hole to be made. The top surface of the molding top core 8 inside the boss 8.1 is a circular area 8.2. The circular area 8.2 is milled deep. Even if the bottom surface height of the circular area 8.2 is smaller than the height of the outer top surface 8.3, it is preferably 1mm smaller.

[0041] During operation, the forming punch 6 presses downward on the raised part of the material in step 1, and under the action of the boss on the top surface of the forming top core 8 in the forming die 7, the material between the forming top core 8 and the forming punch 6 is squeezed, so that the material flows to the outside and inside of the boss, so that the material fills the forming die 7, and the circular area 8.2 is milled deep, so that it can accommodate the excess material squeezed to the inside of the boss.

[0042] Furthermore, the radial clearance between the cylindrical section 6.1 of the forming punch and the inner hole of the forming die 7 is 1.7 mm, and the material thickness is 2.0 mm (i.e., the radial clearance between the cylindrical section 6.1 of the forming punch and the inner hole of the forming die 7 is smaller than the material thickness), so that the effect of material thinning can be eliminated by extrusion.

[0043] Furthermore, a push rod 9 is provided at the bottom of the molding top core 8, and a 1-ton nitrogen spring is provided below the push rod, through which the molded blank is pushed out of the molding die.

[0044] Step 3, using a punching punch 10 and a punching die 11 to punch the formed part of the material processed in step 2, to form a preliminary bottom hole on the material. Figure 8 The inner hole of the punching die 11 is a stepped hole, including an upper hole section 11.1 and a lower hole section 11.2. The diameter of the upper hole section 11.1 is 0.1 mm larger than the outer diameter of the forming part of the material after step 2, so that it can be placed in the upper hole section 11.1 of the punching die 11; the blanking clearance between the punch 10 and the lower hole section 11.2 of the punching die 11 is 0.05 mm, ensuring sufficient bright band.

[0045] Step 4, shaping the preliminary bottom hole on the material processed in step 3 using the shaping punch 13 and the shaping die 14. Fig. 9 , the gap between the shaping punch and the shaping die is given to be 1.5mm to eliminate the punching residual in step 3.

[0046] Furthermore, a supporting core 15 is provided in the inner hole of the shaping die 14 , and a return spring 16 is provided at the bottom of the supporting core. The supporting core 15 is used to push the bottom hole after shaping out of the shaping die 14 .

[0047] Step 5, using the pressing plate 17, the chamfering sleeve 18, and the chamfering insert 19 to chamfer the bottom of the bottom hole on the material processed in step 4. Fig.10 The pressing plate 17 is used to press the material onto the chamfering sleeve 18. The chamfering insert 19 is embedded in the chamfering sleeve 18. The top of the chamfering insert 19 is provided with an effective end for chamfering the bottom of the bottom hole of the material. The effective end includes a first cylindrical section 19.1 and a chamfering bevel section 19.2 located below the first cylindrical section 19.1. The diameter of the chamfering bevel section 19.2 gradually increases from top to bottom. Below the chamfering bevel section 19.2 is the main body section of the chamfering insert 19. The diameter of the main body section is slightly larger than the maximum diameter of the chamfering bevel section 19.2.

[0048] Furthermore, a push rod 20 is vertically provided in the chamfering sleeve 18 , and the bottom end of the push rod 20 is connected to a return spring 21 , so that the chamfered material is pushed upward out of the chamfering sleeve 18 through the push rod 20 .

[0049] For ease of explanation, spatial relative terms such as "upper", "lower", "left", "right" and the like are used in the embodiments to illustrate the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "on" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0050] Furthermore, relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0051] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A bottom hole forming method for high-strength steel plate, characterized in that: The following steps are involved: Step 1, using a convex punch and a convex die to punch the material to make the material convex; Step 2, punching the convex part of the material in step 1 by using a forming punch, a forming die, and a forming top core; The molding top core is arranged in the inner hole of the molding die, a circle of bosses is arranged on the top of the molding top core, the top portion of the molding top core outside the bosses is divided into an outer top surface, the outer top surface is a plane, when the molding top core is at the lower limit position, the height position of the outer top surface of the molding top core is just the terminal position of the bottom hole of the material to be made; the top surface portion of the molding top core inside the boss is a circular area, the circular area is milled to make the bottom surface height of the circular area smaller than the height of the outer top surface; The forming punch presses downward the convex part of the material in step 1, and under the action of the boss on the top surface of the forming top core in the forming die, the material between the forming top core and the forming punch is squeezed, so that the material flows to the outside and inside of the boss, so that the material fills the forming die, and the circular area accommodates the excess material squeezed to the inside of the boss; Step 3, using a punching punch and a punching die to punch the formed part of the material processed in step 2 to form a preliminary bottom hole on the material; Step 4, shaping the preliminary bottom hole on the material processed in step 3 using a shaping punch and a shaping die to eliminate the punching residual in step 3; Step 5, chamfering the bottom of the bottom hole on the material processed in step 4; Among them, the effective end of the forming punch includes a cylindrical section and a chamfered section above the cylindrical section; the radial clearance between the cylindrical section of the forming punch and the inner hole of the forming die is smaller than the material thickness; the inner hole of the punching die is a stepped hole, including an upper hole section and a lower hole section, and the diameter of the upper hole section is 0.1mm larger than the outer diameter of the forming part of the material after processing in step 2; the blanking clearance between the punching punch and the lower hole section of the punching die is 0.05mm.

2. The bottom hole forming method for high-strength steel plate according to claim 1, characterized in that: The active end of the embossing punch is hemispherical, and the embossing die has an inner hole corresponding to the embossing punch. The embossing punch punches toward the inner hole of the embossing die, so that the punched material forms an arc-shaped embossment in the inner hole of the embossing die.

3. The bottom hole forming method for high-strength steel plate according to claim 2, characterized in that: A supporting core is also arranged in the inner hole of the embossing die, and a return spring is arranged at the bottom of the supporting core. The supporting core can be used to push the embossed part of the material out of the embossing die after the material is stamped and embossed.

4. The bottom hole forming method for high-strength steel plate according to claim 1, characterized in that: The boss is used for drafting, the draft angle is 45°-55°, and the boss height is 1.0mm.

5. The bottom hole forming method for high-strength steel plate according to claim 1, characterized in that: The gap between the shaping punch and the shaping die is given as 1.5mm. A supporting core is also arranged in the inner hole of the shaping die. A return spring is arranged at the bottom of the supporting core. The supporting core is used to push the bottom hole after shaping out of the shaping die.

6. The bottom hole forming method for high-strength steel plate according to claim 1, characterized in that: The bottom hole of the material processed in step 4 is chamfered by using a pressing plate, a chamfering sleeve and a chamfering insert. The pressing plate is used to press the material against the chamfering sleeve. The chamfering insert is embedded in the chamfering sleeve. The top of the chamfering insert is provided with an effective end for chamfering the bottom of the bottom hole of the material. The effective end includes a first cylindrical section and a chamfering bevel section located below the first cylindrical section. The diameter of the chamfering bevel section gradually increases from top to bottom. Below the chamfering bevel section is the main body section of the chamfering insert. The diameter of the main body section is greater than the maximum diameter of the chamfering bevel section.

7. The bottom hole forming method for high-strength steel plate according to claim 6, characterized in that: A push rod is also vertically arranged in the chamfering sleeve, and the bottom end of the push rod is connected to a return spring, so that the chamfered material is pushed upward out of the chamfering sleeve through the push rod.

Images