TWI785902B - Manufacturing method for nut - Google Patents

Abstract

A method for manufacturing a nut is used for solving the problems that too many wastes are generated and manufacturing time consuming in the conventional vehicle nut manufacturing procedure. The method comprises a segmental forming method for processing a nut blank. In the segmental forming method, making a punch head move an upward distance toward a lifting direction in first, and then making the punch head move a segmental downward distance toward a compressing direction. The upward distance is smaller than the segmental downward distance. The segmental forming method is implemented for a segmental times, and the segmental times is implemented at least one time. After completing the segmental forming method, making the punch head move toward the compressing direction to forming the nut blank to a formed blank which has a shape and a blind hole. Said shape of the formed blank corresponds to the mold cavity with a second radial width smaller than a first radial width.

Description

Nut manufacturing method

The invention relates to a method for manufacturing a nut, in particular to a method for manufacturing a nut for a wheel.

Please refer to Figure 1, which is a known manufacturing method of wheel nuts and the state of blanks corresponding to each stage. The manufacturing method of the nuts includes the following stages: Stage 1: blanking to form a blank 9a; Stage 2 : the blank 9a is roughly forged and/or shaped to form a blank 9b with a specific shape, which may include the formation of a positioning hole 90; stage three: the blank 9b is through-holed to have a through-hole 90 A blank 9c of '; stage four: welding a cap 91 on one side of the through hole 90' to form a blank 9d with the cap 91; stage five: car repairing the blank 9d and the cap 91 The outer shape forms a blank 9e.

The above-mentioned conventional nut manufacturing method, that is, the so-called general through-hole nut forging, in the through-hole stage (stage 3), it is necessary to implement a punching and shearing forming after forging to remove the middle of the nut forging. For the web plate, the volume of the removed web plate is about 10% to 25% of the volume of the forging product. Therefore, mass production of through-hole nut forging products will lead to excessive waste, and due to the subsequent welding process ( Stage 4) and vehicle repair shape (stage 5), will lead to increased manpower consumption and time costs.

In view of this, it is necessary to improve the known nut manufacturing method.

In order to solve the above problems, the purpose of the present invention is to provide a method for manufacturing nuts, which can reduce the production of waste materials, and reduce labor and time costs.

The second object of the present invention is to provide a method for manufacturing nuts, which can provide an improved segmented process/multi-stage forging method according to the shape characteristics of the forming part of the master mold, so that the manufactured forming blanks are not easy to have stacking, and the manufacturing process is improved. quality.

Directionality or similar terms used throughout the present invention, such as "front", "rear", "left", "right", "upper (top)", "lower (bottom)", "inner", "outer" , "side", etc., mainly refer to the directions of the attached drawings, and each direction or its approximate terms are only used to assist in explaining and understanding the various embodiments of the present invention, and are not intended to limit the present invention.

The elements and components described throughout the present invention use the quantifier "a" or "an" only for convenience and to provide the usual meaning of the scope of the present invention; in the present invention, it should be interpreted as including one or at least one, and singular The notion of also includes the plural unless it is obvious that it means otherwise.

Approximate terms such as "combination", "combination" or "assembly" mentioned throughout the present invention mainly include forms that can be separated without destroying the components after connection, or that the components cannot be separated after connection, etc., which are common knowledge in the art. One can be selected according to the material of the components to be connected or assembly requirements.

The manufacturing method of the nut of the present invention includes: providing a female mold, the female mold has a first end and a second end opposite to each other in the axial direction, the first end defines a pressing direction toward the axial direction of the second end, The second end defines a lifting direction toward the axial direction of the first end, the master mold has a mold cavity extending along an axial direction, and the mold cavity has a first diameter width and a second diameter width less than the first diameter width; a billet to be processed is placed in the mold cavity; a punch is brought into contact with the billet to be processed and pressed down toward the Direction movement; perform a segmented process, in the segmented process, first move the punch to the lifting direction for a lifting distance, then move the punch to the pressing direction for a segmented punching distance, and the lifting The distance is less than the segmental punching distance; wherein, the segmented process is executed for a total number of segmented times, and the segmented number of times is at least 1; and after performing the segmented process, the punch is moved in the pressing direction, The blank to be processed is formed into a shaped blank, the shaped blank has a shape corresponding to the second diameter width smaller than the first diameter width in the mold cavity and has a blind hole.

Accordingly, the nut manufacturing method of the present invention can produce a high-quality formed blank with blind holes and a predetermined shape through the step-by-step process of processing the blank to be processed, and does not need to perform welding and turning Modifying the shape can reduce waste generation, manpower consumption and time cost.

Wherein, there may be a female mold forming part in the mold cavity, and the female mold forming part may have an inwardly convex shape, and the forming blank may have a blank forming part corresponding to the female mold forming part. In this way, through the configuration of the forming part of the master mold, the forming blank can have a shape corresponding to the forming part of the master mold and is easy to manufacture, which has the effect of improving the quality and overall appearance of the forming blank.

Wherein, the female molding portion may have a surface defined by at least one fillet radius. In this way, through the lifting distance, it can be ensured that the punch is completely separated from the blank to be processed, which has the effect of improving the quality of the formed blank.

Wherein, the forming part of the master mold may have a surface defined by at least one fillet radius, and the lift distance may be equal to the sum of the fillet radius of the forming part of the master mold and the margin value, and the range of the margin value may be Between 0.01mm~0.1mm. In this way, an appropriate lifting distance can be obtained through the selection of the margin value, ensuring that the punch is completely separated from the blank to be processed, and has the effect of improving the quality of the formed blank.

Wherein, the number of divisions may be at least 2 times. In this way, the blank to be processed can be processed by executing the segmented process for a large number of segmentation times, which has the effect of improving the quality of the formed blank.

Wherein, there may be a female mold forming part in the mold cavity, and the surface of the female mold forming part may be having a first end, a second end, and a critical position, the critical position may be located between the first end and the second end of the master mold forming portion, a second distance may be defined as from the master mold As for an axial length from the first end of the forming part to a critical position, the segmental stamping distance may be equal to the second distance divided by the number of segments and then the lifting distance added. In this way, through the segmental punching distance, the occurrence of overlapping materials during the forging and pressing forming process can be avoided, which has the effect of improving the quality of the forming blank.

Wherein, there may be a forming angle at any position on the surface of the forming portion of the master mold, and the forming angle may be defined as an acute angle between a tangent direction from any position and an axial direction; the critical position may be It is a position having a forming angle not greater than an inclination angle and closest to the first end of the forming part of the master mold; the inclination angle can range from 10 degrees to 20 degrees. In this way, an appropriate segmented punching distance can be obtained through the selection of the inclination angle, avoiding the occurrence of overlapping materials during the forging and pressing forming process, and having the effect of improving the quality of the formed blank.

Wherein, the inclination angle may be 15 degrees. In this way, a better segmented punching distance can be obtained through the selection of the inclination angle, avoiding the overlapping of materials during the forging process, and having the effect of improving the quality of the formed blank.

Wherein, in the case where the blank to be processed is placed in the mold cavity, there may be a first distance between the blank to be processed and the forming part of the female mold, which is the smallest distance in the axial direction; the punch After contacting the workpiece to be processed and moving the first distance in the pressing direction, the segmented process is executed. In this way, the segmented process can be carried out at a preferred position (such as the position corresponding to the change in the diameter and width of the mold cavity or the position that initially contacts the forming part of the master mold), so as to avoid the occurrence of overlapping materials during the forging and pressing forming process, and has the effect of improving the The effect of forming blank quality.

Wherein, the material of the blank to be processed is any one selected from carbon steel, alloy and stainless steel; in the case of carbon steel, the number of divisions is 3 to 5 times; When the material of the billet to be processed is alloy, the number of divisions is more than 6; when the material of the billet to be processed is stainless steel, the number of divisions is more than 10 times. Thus, depending on the material Formability selects the optimal number of times for multi-stage forging of the blank to be processed, avoiding material stacking during the forging process, and has the effect of improving the quality of the forming blank.

〔this invention〕

1a: Initial stock

1b: Shaping embryo material

10b: Positioning hole

1c: blank material to be processed

10c: inner hole

11c: first end

12c: second end

13c: head

14c: Extension

1d: Formed blank

10d: blind hole

11d: first end

12d: second end

13d: head

14d: Extension

15: Blank forming department

2: master model

2a: first end

2b: second end

20: Mold cavity

201: The first space

201A: The first subspace

202: Second space

203: The third space

21: Master mold forming department

21a: first end

21b: second end

21c: critical position

3: Punch

D _1c : Maximum head diameter width

D _2c : Diameter width of extension

D _1d : Maximum head diameter width

D _2d : Diameter width of extension

D ₂₀₁ : diameter width of the first space

D ₂₀₂ : Diameter width of the second space

D ₂₀₃ : Diameter width of the third space

L1: first distance

L2: second distance

R: fillet radius

S _u : Lifting distance

S _d : segmental stamping distance

T: number of segments

θc: critical forming angle

△T: margin value

〔usual〕

9a, 9b, 9c, 9d, 9e: blank material

90: positioning hole

90': through hole

91: cap

[Fig. 1] A manufacturing process of a conventional wheel nut.

[Fig. 2] Nut manufacturing process of a preferred embodiment of the present invention.

[Fig. 3] a master mold of a preferred embodiment of the present invention.

[Fig. 4] Corresponding to Fig. 3, a partially enlarged cross-sectional schematic diagram of the forming part of the master die.

[Fig. 5] The implementation schematic diagram of the method of the present invention when the blank to be processed is placed on the master mold.

[Fig. 6] A schematic diagram of the implementation of the method of the present invention to press the punch down a first distance.

[Fig. 7] A schematic diagram of the implementation of the method of the present invention to lift the punch up by a lifting distance.

[the 8th figure] the implementation schematic diagram of the method of the present invention makes the punch press down a segmental stamping distance.

[Fig. 9] It is a schematic diagram of punch stroke versus time in an example of implementing the method of the present invention.

In order to make the above-mentioned and other objects, features and advantages of the present invention more obvious and understandable, the preferred embodiments of the present invention are specifically cited below, and are described in detail in conjunction with the accompanying drawings; in addition, the same symbols are marked in different drawings are considered the same, and their descriptions will be omitted.

Please refer to Fig. 2, which is a nut manufacturing method of a preferred embodiment of the present invention and the state of blanks corresponding to each stage. The nut manufacturing method includes the following stages: Stage 1: blanking to form an initial blank 1a; Stage 2: rough forging and/or shaping the initial blank 1a to form a shaped blank 1b having a specific shape, which may include the shape of a positioning hole 10b into; stage three: form the shaping blank material piece 1b into a blank material piece 1c to be processed with an inner hole 10c; stage four: process the blank material 1c to be processed with a multi-stage forging/stamping method, and make the blank material piece 1c to be processed The blank to be processed 1c is formed into a shaped blank 1d having a blind hole 10d and a predetermined shape.

Please refer to FIG. 2 , the blank to be processed 1c has a first end 11c and a second end 12c opposite to each other in the axial direction. The blank to be processed may have an inner hole 10c, the inner hole 10c is a blind hole, and the inner hole 10c is recessed from the first end 11c toward the second end 12c. The blank 1c to be processed may have a head 13c and an extension 14c; the head 13c may have a maximum head diameter D 1c in a radial direction, and the extension 14c may have a radial width D _1c The extension width D _2c , the head width D _1c is greater than the extension width D _2c .

Please refer to Figure 2, the forming blank 1d has a first end 11d and a second end 12d axially opposite, the blind hole 10d of the forming blank 1d is from the first end 11d toward the second The two ends 12d are recessed. The shaped blank 1d has a blank forming portion 15 having a shape corresponding to a predetermined outer shape. Preferably, the billet forming portion 15 extends from the second end 12d toward the first end 11d. The blank forming portion 15 can be in a concave shape; preferably, the forming portion 15 is tapered from a place near the first end 11d to the second end 12d; more preferably, the forming portion 15 is smaller A radial width near the first end 11d is not smaller than a radial width closer to the second end 12d. The forming blank 1d may have a head 13d and an extension 14d, the head 13d extends from the first end 11d toward the second end 12d, the extension 14d is connected to the head 13d and the forming portion 15 between. The head portion 13d may have a maximum head diameter width D _1d in a radial direction, and the extension portion 14d may have an extension portion width D _2d in a radial direction, the head width D _1d being greater than the extension portion width D _2d .

Please refer to Figure 3, which shows a female mold 2 for forming the blank 1c to be processed into the shaped blank 1d, the female mold 2 has a mold cavity 20 extending along an axial direction, the mold cavity 20 The diameter width of the mold cavity varies in the axial direction; preferably, the mold cavity 20 has a first diameter width and a second diameter width smaller than the first diameter width, so as to define a diameter variation of the mold cavity 20 /area. Specifically, the female mold 2 has a female mold forming part 21 in the mold cavity 20, and the female mold forming part 21 has an inwardly convex shape; preferably, the mold cavity 20 has a A closed end 20c, the female mold forming portion 21 is connected to the closed end 20c; preferably, the female mold forming portion 21 has a gradually expanding shape from an end far away from the closed end 20c toward the closed end 20c. Preferably, the above-mentioned place where the diameter width changes can be the forming part 21 of the female mold.

Please refer to Figure 3, in detail, the female mold 2 may have a first end 2a and a second end 2b axially opposite each other, and the mold cavity 20 is from the first end 2a to the second end 2b The depression forms a blind hole; preferably, the position where the second diameter is wider than the first diameter is closer to the second end 2b. A first space 201, a second space 202, and a third space 203 can be defined between the master mold 2 and the mold cavity 20, and the first space 201, the second space 202, and the third space 203 have a first space respectively. A space diameter D ₂₀₁ , a second space diameter D ₂₀₂ and a third space diameter D ₂₀₃ , the first space diameter D ₂₀₁ is greater than the second space diameter D ₂₀₂ , the third space diameter D ₂₀₃ is tapered from the overlapping boundary of the second space 202 and the third space 203 toward the direction of the second end 2b. In one example, the above-mentioned first diameter may be the second space diameter D ₂₀₂ , and the above-mentioned second diameter may be the third space diameter D ₂₀₃ ; in another example, the above-mentioned first diameter, the second space diameter The two diameters are respectively the diameters away from and close to the second end 2 b of the third space diameter D ₂₀₃ . Preferably, the first space 201 includes a first subspace 201A, the first subspace 201A is connected between the first space 201 and the second space 202, the diameter of the first subspace 201A is from the The first space 201 tapers toward the direction of the second space 202 . The female molding part 21 can be formed in the third space 203 . Preferably, the profile of the female mold forming portion 21 gradually expands along the direction from the first end 2 a to the second end 2 b.

Please refer to Figure 4, which shows the schematic diagram of the change in diameter or the forming part 21 of the female mold. Preferably, the change in diameter or the forming part 21 of the female mold has at least one fillet radius R Defined surface; preferably, any position on the surface of the change in diameter width or the forming part 21 of the master mold has a forming angle, and the forming angle is defined as forming from the change in diameter width or the master mold An acute included angle between a tangential direction at any part of the portion 21 and an axial direction. More preferably, the change in diameter or the surface of the mold forming part 21 has a first end 21a, a second end 21b and a critical position 21c, the critical position 21c is located at the change in diameter or the master mold Between the first end 21a and the second end 21b of the forming part 21, the critical position 21c is the part that has a critical forming angle θc not greater than an inclination angle and is closest to the change in diameter or the forming part of the master mold. A position of the first end 21a; in other words, the critical position 21c has an inclination equal to an inclination angle on the surface of the first end 21a toward the second end 21b of the diameter width variation or the female mold forming portion 21 An initial position, and the forming angle of the change in diameter width or any position of the female mold forming portion 21 on the surface between the first end 21a and the critical position 21c is greater than the critical forming angle θc; the inclination The angle ranges from 10° to 20°, and can be adjusted at intervals of 0.1°; the inclination angle is preferably 15°.

According to aforementioned structure, the present invention can implement a kind of nut manufacturing method, comprises the following steps:

Please refer to Figures 3 to 4, the aforementioned female mold 2 is provided, the female mold has a first end 2a and a second end 2b axially opposite each other, the first end 2a faces the axial direction of the second end 2b The direction defines a pressing direction, and the second end 2b defines a lifting direction toward the axial direction of the first end 2a. The female mold 2 has a mold cavity 20 extending along an axial direction, and the mold cavity 20 has a A first diameter and a second diameter are smaller than the first diameter. Preferably, the female mold 2 has a female mold forming portion 21 inside the mold cavity 20 , and the female mold forming portion 21 has an inwardly protruding shape.

Please refer to FIG. 5 , place the blank 1c to be processed in the mold cavity 20 . Preferably, the blank 1c to be processed does not coincide with the forming portion 21 of the female mold in the radial direction, so that there is a first distance L1 between the blank 1c to be processed and the forming portion 21 of the female mold; The first distance L1 can be defined as the minimum axial distance between the blank 1c to be processed and the forming part 21 of the master mold; in one example In this case, only the adjacent ends of the blank 1c to be processed and the forming portion 21 of the master mold overlap each other in the radial direction, so that the first distance L1 is zero.

Please refer to Figures 5-6, make a punch 3 contact with the blank 1c to be processed (as shown in Figure 5), and make the punch 3 move towards the pressing direction (as shown in Figure 6 shown), preferably move the first distance L1 toward the pressing direction. Preferably, the punch 3 extends into the inner hole 10c of the blank 1c to be processed, and the end of the punch 3 abuts against the bottom end of the inner hole 10c.

Please refer to Figures 7 to 8 to perform a step-by-step process to process the blank 1c to be processed. In the segmented process, the punch 3 is first moved toward the lifting direction by a lifting distance _Su (as shown in Figure 7), and then the punch 3 is moved toward the pressing direction by a segmental punching distance S _d (as shown in Figure 8); wherein, the lifting distance Su is less than the _segmented stamping distance S _d ; and wherein, the segmented process is executed for a segmented number of times T, and the segmented number of times T is at least 1 Second-rate. Process the blank to be processed 1c through the step-by-step process, especially when the blank to be processed 1c is punched by the punch 3 to the position corresponding to the change of the first diameter width and the second diameter width in the mold cavity 20 (preferably corresponding to the forming part 21 of the mother mold), the blank to be processed 1c or the forming blank 1d can be made to correspond to the change in diameter of the mold cavity 20 (preferably at the forming part 21 of the mother mold) The location/area has better material properties and form quality.

Please refer to Fig. 9, after performing the step-by-step process, the punch 3 is moved toward the pressing direction, so that the blank 1c to be processed is formed into a forming blank 1d, and the forming blank 1d has a corresponding The mold cavity 20 has a shape in which the second diameter is smaller than the first diameter (preferably has a blank forming portion 15 corresponding to the female mold forming portion 21 ) and has the blind hole 10d. It has a blank forming portion 15 corresponding to the female mold forming portion 21 and has the blind hole 10d. In detail, the aforementioned blank forming part 15 corresponds to the master mold forming part 21 means that the blank forming part 15 and the master mold forming part 21 fit each other in contour geometry.

It should be noted that Figures 5-8 mainly illustrate the stroke and position changes of the punch 3 during the manufacturing process of the nut, and do not specifically show the deformation of the blank 1c to be processed during the manufacturing process.

The lifting distance _Su is used to completely separate the punch 3 from the blank 1c to be processed before stamping the blank 1c to be processed, so as to achieve segmental stamping, which has the effect of improving the quality of the blank 1d to be processed. effect. It should be noted that, as shown in FIG. 6 , regardless of the deformation of the blank 1c to be processed, when the punch 3 punches the blank 1c with the first distance L1, the blank 1c to be processed will A radial position corresponds to the change in diameter of the mold cavity 20 (preferably the female mold forming part 21); however, if considering the deformation of the blank 1c to be processed during the forging process, at this time, the waiting The processing blank 1c may have been in contact with the diameter variation of the mold cavity 20 (preferably the forming part 21 of the female mold), and by raising the punch 3 by the lifting distance S _u , the punch 3 and the The complete detachment of the blank to be processed 1c will facilitate the subsequent segmental punching, so that a shape/region (preferably the blank forming part 15) of the formed blank 1d is more suitable for the diameter of the mold cavity 20 Wide variation (preferably the master mold forming part 21). The lift distance S _u can be defined as follows: S _u =R+ΔT; wherein, R is the change in diameter of the mold cavity 20 or a fillet radius of the female mold forming portion 21; in one example, the mold cavity 20 The change of the diameter width of the or the female mold forming part 21 may have several fillet radii, and R is the maximum value among the several fillet radii. ΔT is a margin value, the margin value ΔT ranges from 0.01mm to 0.1mm, and can be adjusted at a pitch of 0.01mm; the margin S _a is preferably 0.05mm. Therefore, the lifting distance _Su is equal to the sum of the fillet radius R and a margin value ΔT. In addition, the lifting distance _Su can also only be equal to the fillet radius R.

The segmented stamping distance S _d is corresponding to the change in the diameter of the mold cavity 20 or the contour characteristics of the forming part 21 of the master mold. The blank 1c is stamped in a segmented manner to make the blank forming part of the formed blank 1d 15 It is not easy to have the situation of overlapping materials, which has the effect of improving the quality of the forming blank 1d. The segmental stamping distance S _d can be defined as follows: S _d =L2/T+S _u ; wherein, as shown in Figure 8, L2 is a second distance, and the second distance L2 is defined as changing from the diameter or the axial length from the first end 21a of the female mold forming part 21 to the critical position 21c. Wherein, the inclination angle can correspond to the draft angle, so by properly selecting the inclination angle, the quality of the blank forming portion 15 of the formed blank 1d can be better improved. Therefore, the segmented stamping distance S _d is equal to the second distance L2 divided by the number of segments T plus the lifting distance _Su . It should be noted that, according to the above definition, in some examples, the critical position 21c can be the second end 21b.

Preferably, the segmentation times T is at least 2 times; more preferably, the segmentation times T is at least 3 times. In detail, the number of divisions T is mainly determined according to the material formability of the blank to be processed 1c. For example, when the material of the blank 1c to be processed is carbon steel, the number of divisions T is 3~5 times; when the material of the blank 1c is an alloy, the number of divisions T is more than 6 times; when the material of the blank 1c is stainless steel, the number of divisions T is more than 10 times. Therefore, the number of divisions T can be appropriately selected according to the formability of the material, so that the quality of the blank forming portion 15 of the formed blank 1d can be better improved.

Please refer to Figure 9, which is an implementation example of the method according to the present invention, showing the stamping stroke diagram of the punch 3, and the symbol _PS is a trigger position, indicating that the punch 3 starts to execute the multi-stage stamping stroke position; label _PE is an end position, indicating that the punch 3 completes the stroke position of the multi-stage punching; The blank 1c fills the mold cavity 20 to form the shaped blank 1d having the blank forming portion 15 and a blind hole 10d of a predetermined depth. In this implementation example, the first distance L1 is 2mm, the second distance L2 is 5mm, the inclination angle is 15 degrees, the fillet radius R is 0.2mm, and the margin value ΔT is 0.05mm. The material of the billet 1c is carbon steel, and the corresponding number of subsections T is 4; accordingly, the corresponding lifting distance _Su is 0.25 mm, and the subdivision punching distance S _d is 1.5 mm.

To sum up, the nut manufacturing method of the present invention proposes a step-by-step processing method through the variation of the die cavity diameter corresponding to the female mold (especially through the characteristics of the forming part of the corresponding female mold), and A nut with a specific shape and blind hole can be formed in one processing pass, which can help to improve the waste problem of the mass production of the nut, and help to reduce the cost and improve the forming quality.

Although the present invention has been disclosed by using the above-mentioned preferred embodiments, it is not intended to limit the present invention. It is still within the scope of this invention for anyone skilled in the art to make various changes and modifications relative to the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall include all changes within the meaning and equivalent scope described in the appended scope of application.

1a: Initial stock

1b: Shaping embryo material

10b: Positioning hole

1c: blank material to be processed

10c: inner hole

11c: first end

12c: second end

13c: head

14c: Extension

1d: Formed blank

10d: blind hole

11d: first end

12d: second end

13d: head

14d: Extension

15: Blank forming department

D _1c : Maximum head diameter width

D _2c : Diameter width of extension

D _1d : Maximum head diameter width

D _2d : Diameter width of extension

Claims (10)

A method for manufacturing a nut, comprising: providing a female mold, the female mold has a first end and a second end opposite to each other in the axial direction, the first end defines a pressing direction toward the axial direction of the second end, the first end The two ends define a lifting direction toward the axial direction of the first end, the master mold has a mold cavity extending along an axial direction, and the mold cavity has a first diameter width and a second diameter width smaller than the The first diameter is wide; a billet to be processed is placed in the mold cavity; a punch is brought into contact with the billet to be processed and moved toward the pressing direction; a segmented process is performed, and in the segmented process, First move the punch to the lifting direction for a lifting distance, and then move the punch to the pressing direction for a segmented punching distance, and the lifting distance is smaller than the segmented punching distance; wherein, the segmented process is executed in total a number of divisions, the number of divisions being at least 1; and after performing the division process, moving the punch in the pressing direction so that the blank to be processed is formed into a shaped blank, the formed blank It has a shape corresponding to the second diameter width smaller than the first diameter width in the mold cavity and has a blind hole. The method for manufacturing nuts as claimed in claim 1, wherein, there is a female mold forming part in the mold cavity, the female mold forming part has an inwardly convex shape, and the forming blank has a blank corresponding to the female mold forming part Forming department. The method for manufacturing a nut according to claim 2, wherein the female die forming portion has a surface defined by at least one fillet radius, and the lift distance is equal to the fillet radius of the female die forming portion. The nut manufacturing method according to claim 2, wherein the female mold forming portion has a surface defined by at least one fillet radius, and the lift distance is equal to the sum of the fillet radius of the female mold forming portion and a margin value, The margin value ranges from 0.01 mm to 0.1 mm. The nut manufacturing method according to claim 1, wherein the number of divisions is at least 2. The method for manufacturing nuts according to claim 5, wherein, there is a female mold forming part in the mold cavity, and the surface of the female mold forming part has a first end, a second end and a critical position, and the critical position is located at the Between the first end and the second end of the female mold forming portion, a second distance is defined as an axial length from the first end of the female mold forming portion to a critical position, the segmented punching distance It is equal to dividing the second distance by the number of divisions and adding the lifting distance. The nut manufacturing method according to claim 6, wherein there is a forming angle at any position on the surface of the forming part of the master mold, and the forming angle is defined as between a tangent line direction from the any position and an axial direction The acute angle included angle; the critical position is a position having a forming angle not greater than an inclination angle and closest to the first end of the mold forming part; the inclination angle ranges from 10 degrees to 20 degrees. The method for manufacturing a nut according to claim 7, wherein the inclination angle is 15 degrees. The nut manufacturing method according to claim 2, wherein, when the blank to be processed is placed in the mold cavity, there is a minimum distance between the blank to be processed and the forming part of the female mold in the axial direction A first distance; after making the punch contact with the blank to be processed and moving the first distance toward the pressing direction, the segmented process is executed. The nut manufacturing method according to any one of claims 1 to 9, wherein the material of the blank to be processed is any one selected from carbon steel, alloy and stainless steel; the material of the blank to be processed is In the case of carbon steel, the number of divisions is 3 to 5 times; when the material of the billet to be processed is an alloy, the number of divisions is more than 6 times; In some cases, the number of divisions is 10 or more.

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