A mold for improving the internal hole step and its processing method

Abstract

This invention relates to a mold for improving the internal diameter step, comprising a moving mold base and a stationary mold base, and further comprising multiple forming stations for cold heading, a punching station, and an internal diameter shaping station for stretching and shaping the internal diameter, arranged sequentially. The punching station includes a punching die and a punching punch for punching through holes into the cold-headed blank. The punching die is provided with a positioning block and a first pad block, which are respectively positioned at both ends of the positioning hole. The first pad block has a discharge channel. The internal diameter shaping station includes a shaping die and a stretching punch for stretching and shaping the punched internal diameter. The shaping die is positioned on the stationary mold base, and the stretching punch is positioned on the moving mold base. The shaping die is provided with a positioning block and a second pad block positioned below the blank. The second pad block has a receiving cavity, and a gap is provided between the stretching punch and the receiving cavity. By adopting the above technical solution, problems such as excessive internal diameter step, excessive internal diameter flare angle, and internal diameter tearing can be solved, enabling automated production.

Description

Technical Field

[0001] This invention belongs to the field of mechanical technology, specifically relating to a mold for improving the internal hole steps and its processing method. Background Technology

[0002] Existing mold products have pre-punching before punching, which results in steps and flared mouths in the inner hole of the product after punching. In addition, the extrusion of waste material during punching by the punch can cause tearing marks in the inner hole, which does not meet the current product requirements. Therefore, how to achieve simple and efficient production to meet the product requirements of smooth inner hole, no tearing marks after punching, and no steps is an urgent problem to be solved. Summary of the Invention

[0003] In summary, to overcome the shortcomings of the prior art, the present invention provides a machining mold assembly for improving the inner hole step flange diameter and eccentric threaded hole integral molding, thereby improving dimensional accuracy.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a mold for improving the internal hole step, comprising a moving mold base and a stationary mold base, and further comprising a plurality of forming stations for cold heading, a punching station for punching, and an internal hole shaping station for stretching and shaping the internal hole, arranged sequentially. The punching station includes a punching die and a punching punch for punching through holes in the cold-headed blank. The punching die is provided with a first positioning block and a first pad for positioning the blank. The first pad and the punching punch are respectively disposed on the... At both ends of a positioning block, the first pad block is provided with a discharge channel adapted to the punching punch; the inner hole shaping station includes a shaping die and a stretching punch for stretching and shaping the inner diameter of the punched blank. The shaping die is set on the stationary die base, and the stretching punch is set on the moving die base. The shaping die is provided with a second positioning block 52 for positioning the blank and a second pad block set below the blank. The second pad block is provided with a receiving cavity adapted to the stretching punch, and a gap is provided between the stretching punch and the receiving cavity.

[0005] By adopting the above technical solution, compared with the prior art, where cold heading punching is mostly located in the last step of the process and there is often a pre-punching step before punching to avoid a large number of tears caused by direct punching, the existing technology still has problems such as steps in the inner hole, large flared openings, and tears. Even if there is a shaping station mold after punching in the prior art, it is used to shape the shape of the final product blank rather than the inner diameter. The technical solution of this invention adds an inner hole shaping station after punching, and through stretching and shaping of the punch rather than the shaping of the mold, it can solve the problems of steps in the inner hole, large flared openings, and inner diameter tears in punched products. The punch has a distinct flared opening, with a difference in inner diameter between the upper and lower ends reaching 0.4-0.5mm. In contrast, the inner diameter difference at the upper end of the product obtained in the technical solution of this invention is only 0.05-0.1mm, which almost solves the problem of excessive flared opening angle. Moreover, it can be implemented on a multi-station cold heading machine, enabling automated production with high efficiency. The gap between the drawing punch and the receiving cavity is set so that the stroke and depth of the drawing punch into the receiving cavity can be adjusted according to the product specifications, but the drawing punch does not collide with the bottom wall of the receiving cavity, reducing wear and extending service life. Depending on the shape of the product, the punch can be set on either the moving die base or the stationary die base as required.

[0006] The present invention further comprises: the stretching punch includes a guide section, a shaping section and an extension section arranged in sequence, the diameter of the shaping section is larger than the diameter of the guide section, the guide section is disposed at one end of the stretching punch corresponding to the stationary mold base, and a transition section is provided between the guide section and the shaping section, the longitudinal section of the transition section is an isosceles trapezoid, and the included angle formed between the two sides of the trapezoid is 20-32°.

[0007] By adopting the above technical solution, due to the problems of the steps and large flared mouth in the inner hole, when the stretching punch is pushed into the inner hole of the punching blank, it first becomes smaller and then larger, forming a guiding effect, making the inner hole of the blank smoother, while reducing the pressure of inner hole shaping and avoiding the generation of tear marks. The transition section makes the insertion from the guiding section to the shaping section smoother. However, if the included angle is greater than 32 degrees, it will lead to excessive resistance, and the stretching punch will not be able to stretch and shape.

[0008] The present invention further provides that the included angle between the two sides of the longitudinal section of the transition segment is 25-30°.

[0009] By adopting the above technical solution, when the included angle is too large, the resistance will increase, causing the inner hole to expand and deform. When the included angle is too small, the stroke needs to be lengthened. However, if the stroke is too long, the mold will become too large, increasing unnecessary production costs.

[0010] The present invention further comprises: the diameter of the molding section is larger than the diameter of the extension section, and a narrowing section for reducing resistance is provided between the molding section and the extension section.

[0011] By adopting the above technical solution, a narrowing section is set to relieve pressure, making the molding section smoother and less labor-intensive when molding the inner hole, reducing the occurrence of tear marks, and improving the smoothness of the inner hole. At the same time, when the stretching punch is pulled back, the narrowing section does not affect the pull-back molding of the molding section, further improving the quality of the inner hole molding. In addition, the stretching punch adopts the stretching principle, which can strengthen the strength of the inner hole.

[0012] The present invention further provides that the outer periphery of the guide segment relative to the other end of the molding segment is rounded.

[0013] By adopting the above technical solution, when the inner diameter of the blank is small, the guide section slides into the inner diameter along the rounded corner, making the inner hole shaping smoother.

[0014] The present invention further comprises: the diameter of the shaping section of the stretching punch is d, the diameter of the guiding section is d1, 0.9d≤d1<0.98d, the diameter of the extension section is d2, d-0.13 mm≤d2≤d-0.1 mm, and the punching punch includes a punching part, the maximum diameter of the punching part being d3, d3=d1+0.05mm.

[0015] The present invention further provides that: a narrowing section is provided on the other side of the punching part relative to the front end, and the slope of the narrowing section of the stretching punch is the same as the slope of the narrowing section of the punching punch.

[0016] The present invention further specifies that the length of the guide segment is L, where L = 0.2d + 2mm, and L is a positive integer, with decimals rounded up.

[0017] By adopting the above technical solution, the guide section has the best stretching and shaping effect on the molding section, resulting in high production efficiency. For example, the diameter of the molding section of the stretching punch is 6mm, and the length of the guide section is 3.2mm, which is rounded up to 4mm.

[0018] The present invention further provides that the surfaces of the guide section, transition section, molding section and extension section are plated with titanium, and the surface finish reaches Ra0.2 or less.

[0019] By adopting the above technical solutions, the hardness and wear resistance of the guide section, transition section, shaping section and extension section of the drawing punch can be further improved, thereby improving dimensional accuracy.

[0020] The present invention further specifies that the material of the stretching punch is M42 or ASP60, and the hardness is 64-67HRC.

[0021] By adopting the above technical solution, the drawing punch has high hardness, strong wear resistance, and extended service life.

[0022] A processing method for improving the inner hole step involves using a mold for improving the inner hole step, and sequentially performing the following steps on the blank: S1: pre-upsetting; S2: second upsetting; S3: upsetting the blank; S4: punching; and S5: stretching and shaping the inner hole.

[0023] By adopting the above technical solution, molds for different internal hole products can be used. Depending on the product shape, steps S1-S3 can be added or removed according to the corresponding requirements of the forming steps. It is not limited to 3-step forming, but can be 4-step, 5-step forming, etc. The technical solution of this invention can solve the problem of excessive inner hole steps and inner hole flared mouth slope in punched products; it can improve the dimensional deviation and quality risk of inner hole steps; it can improve the quality stability of inner hole step components and reduce costs.

[0024] The embodiments describe specific implementations of the present invention. Attached Figure Description

[0025] Figure 1 This is a mold structure diagram for improving the inner hole step according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 Enlarged view of part A;

[0027] Figure 3 for Figure 1 Enlarged view of part B;

[0028] Figure 4 This is a diagram showing the changes in the inner hole of the blank before and after stretching and shaping according to an embodiment of the present invention;

[0029] Figure 5 This is a magnified view of a partial structure of the stretching punch according to an embodiment of the present invention;

[0030] Figure 6 This is a magnified view of a portion of the punching bar according to an embodiment of the present invention;

[0031] Figure 7 This is a process flow diagram of an embodiment of the present invention;

[0032] Figure 8 This is a diagram illustrating the blank forming process of an embodiment of the present invention;

[0033] Reference numerals: 1. Moving mold base, 11. Punching station, 12. Inner hole shaping station, 2. Stationary mold base, 3. Punching die, 31. First positioning block, 32. First pad block, 321. Discharge channel, 4. Punching punch, 41. Punching section, 5. Shaping die, 51. Second pad block, 511. Receiving cavity, 52. Second positioning block, 6. Drawing punch, 61. Guide section, 62. Transition section, 63. Shaping section, 64. Narrowing section, 65. Extension section. Detailed Implementation

[0034] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0035] See appendix Figure 1-8 A mold for improving the internal hole step includes a moving mold base 1 and a stationary mold base 2, and further includes multiple forming stations for cold heading, a punching station 11 for punching, and an internal hole shaping station 12 for stretching and shaping the internal hole, arranged sequentially. The punching station 11 includes a punching die 3 and a punching punch 4 for punching through holes in the cold-headed blank. The punching die 3 is provided with a first positioning block 31 and a first pad block 32 for positioning the blank. The first pad block 32 and the punching punch 4 are respectively disposed at both ends of the first positioning block. 2. A discharge channel 321 adapted to the punching punch 4 is provided; the inner hole shaping station 12 includes a shaping mold 5 and a stretching punch 6 for stretching and shaping the inner diameter of the punched blank. The shaping mold 5 is provided on the stationary mold base 2, and the stretching punch 6 is provided on the moving mold base 1. The shaping mold 5 is provided with a second positioning block 52 for positioning the blank and a second pad block 51 provided below the blank. The second pad block 51 is provided with a receiving cavity 511 adapted to the stretching punch 6, and a gap is provided between the stretching punch 6 and the receiving cavity 511.

[0036] In the technical solution of this invention, the punching station 11 includes a punching die 3 and a punching rod 4 for punching through holes in the cold-forged blank. The punching die 3 is provided with a first positioning block 31 and a first pad block 32 for positioning the blank. The first pad block 32 and the punching rod 4 are respectively disposed at both ends of the first positioning block. The punching rod 4 can be disposed on the moving die base 1 or the stationary die base 2 as required. (Refer to the attached drawing.) Figure 1 The punching rod 4 is set on the stationary mold base 2.

[0037] This embodiment further includes the following configuration: the stretching punch 6 comprises a guide section 61, a shaping section 63, and an extension section 65 arranged sequentially. The diameter of the shaping section 63 is larger than the diameter of the guide section 61. The guide section 61 is located at one end of the stretching punch 6 corresponding to the stationary mold base 2. A transition section 62 is provided between the guide section 61 and the shaping section 63. The longitudinal section of the transition section 62 is an isosceles trapezoid, and the included angle formed between the two sides of the trapezoid is 20-32°.

[0038] In this embodiment, the included angle between the two sides of the longitudinal section of the transition segment 62 is 25-30°.

[0039] In this embodiment, the diameter of the molding section 63 is larger than the diameter of the extension section 65, and a narrowing section 64 for reducing resistance is provided between the molding section 63 and the extension section 65.

[0040] In this embodiment, the outer periphery of the guide segment 61 relative to the other end of the molding segment 63 is rounded.

[0041] In this embodiment, the following configuration is further defined: the diameter of the shaping section 63 of the stretching punch 6 is d, the diameter of the guiding section 61 is d1, 0.9d ≤ d1 < 0.98d, the diameter of the extension section 65 is d2, d - 0.13 mm ≤ d2 ≤ d - 0.1 mm, and the punching punch 4 includes a punching part 41, the maximum diameter of the punching part 41 is d3, d3 = d1 + 0.05 mm.

[0042] In this embodiment, the length of the guide segment 61 is L, where L = 0.2d + 2mm, and L is a positive integer, rounded down to the nearest integer.

[0043] In this embodiment, the guide section 61, transition section 62, molding section 63 and extension section 65 are further configured to be titanium-plated, with a surface finish of Ra0.2 or less.

[0044] In this embodiment, the material of the stretching punch 6 is M42 or ASP60, and the hardness is 64-67HRC.

[0045] A processing method for improving the inner hole step involves using a mold for improving the inner hole step, and sequentially performing the following steps on the blank: S1: pre-upsetting; S2: second upsetting; S3: upsetting the blank; S4: punching; and S5: stretching and shaping the inner hole.

[0046] The "between" mentioned above does not only refer to the location or position, but also to the interaction between different parts.

[0047] Although this document frequently uses terms such as: moving mold base 1, punching station 11, inner hole shaping station 12, stationary mold base 2, punching die 3, first positioning block 31, first pad block 32, discharge channel 321, punching punch 4, punching section 41, shaping die 5, second pad block 51, receiving cavity 511, second positioning block 52, drawing punch 6, guide section 61, transition section 62, shaping section 63, narrowing section 64, extension section 65, etc., the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A mold for improving the internal bore step, comprising a moving mold base and a stationary mold base, characterized in that: It also includes multiple forming stations for cold heading, a punching station for punching, and an inner hole shaping station for stretching and shaping the inner hole, arranged sequentially. The punching station includes a punching die and a punching rod for punching through holes into the cold-headed blank. The punching die is provided with a first positioning block and a first pad for positioning the blank. The first pad and the punching rod are respectively located at both ends of the first positioning block. The first pad is provided with a discharge channel adapted to the punching rod. The inner hole shaping station includes a shaping die and a stretching rod for stretching and shaping the inner diameter of the punched blank. The shaping die is located on the stationary die base, and the stretching rod is located on the moving die base. The device includes a second positioning block for positioning the blank and a second pad block disposed below the blank. The second pad block has a receiving cavity adapted to the drawing punch, and a gap is provided between the drawing punch and the receiving cavity. The drawing punch includes a guide section, a shaping section, and an extension section arranged sequentially. The diameter of the shaping section is larger than the diameter of the guide section. The guide section is disposed at one end of the drawing punch corresponding to the stationary mold base. A transition section is provided between the guide section and the shaping section. The longitudinal section of the transition section is an isosceles trapezoid, and the included angle formed between the two sides of the trapezoid is 20-32°. The diameter of the shaping section is larger than the diameter of the extension section. A narrowing section is provided between the shaping section and the extension section to reduce resistance.

2. The mold for improving the internal bore step according to claim 1, characterized in that: The angle formed between the two sides of the longitudinal section of the transition segment is 25-30°.

3. A mold for improving the internal bore step according to claim 1, characterized in that: The guide section is provided with a rounded corner at the other end relative to the molding section.

4. A mold for improving the internal bore step according to claim 1, characterized in that: The diameter of the forming section of the stretching punch is d, the diameter of the guiding section is d1, 0.9d ≤ d1 < 0.98d, the diameter of the extension section is d2, d - 0.13 mm ≤ d2 ≤ d - 0.1 mm, and the punching punch includes a punching part with a maximum diameter of d3, d3 = d1 + 0.05 mm.

5. A mold for improving the internal bore step according to claim 4, characterized in that: The length of the guide segment is L, where L = 0.2d + 2mm, and L is a positive integer, rounded up when it is a decimal.

6. A mold for improving the internal bore step according to claim 1, characterized in that: The guide section, transition section, molding section and extension section are titanium-plated, and the surface finish reaches Ra0.2 or less.

7. A mold for improving the internal bore step according to claim 1, characterized in that: The material of the stretching punch is M42 or ASP60, and the hardness is 64-67HRC.

8. A processing method for improving the step of an internal hole, characterized in that: Using the mold for improving the inner hole step as described in any one of claims 1 to 7, the blank is subjected to the following steps in sequence: S1: pre-upsetting; S2: second upsetting; S3: upsetting the blank; S4: punching; S5: stretching and shaping the inner hole.

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