Nut forming combined die

Abstract

The utility model discloses a nut forming combined die, which comprises a third die, a fourth die and a fifth die, the third die is used for forming a mushroom head from a front blank to obtain a third blank, and the third die is used for forming the mushroom head in advance to reduce the stress concentration generated when the fourth die is used. Therefore, a procedure corresponding to the fourth die is easier to form, and cracks are not easy to generate. A large space is reserved in the head of the fourth die firstly, so that in the working procedure corresponding to the fifth die, metal on the rim portion flows around preferentially, and a formed chamfer is small and is almost hidden.

Description

Technical Field

[0001] The utility model relates to the field of nut manufacturing equipment, in particular to a nut forming combined die. Background Art

[0002] Fasteners are a type of mechanical parts used for fastening and connection and are extremely widely used. Various fasteners can be seen on various machines, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, meters and supplies.

[0003] Nuts are nuts that are screwed together with bolts or screws to fasten metal or non-metal together. Nuts and bolts of the same specifications can be connected together through the inner threads. Nuts are also divided into different types according to their functions, including anti-loosening nuts, welding nuts, internal and external thread nuts, etc.

[0004] In the prior art, cold heading is used to form the nut. However, when the rim is directly formed by a mold, it is found that the rim is prone to cracking, and on the other hand, there is a large external chamfer between the bottom surface of the rim and the transition of the tooth. Therefore, not only a larger riveting force is required during riveting, but also the external chamfer will interfere with the fitting surface of the fastener to be fastened, resulting in poor sealing during application. In order to reduce the external chamfer, an additional machining process is required, and the machining position is at the bottom of the tooth and the rim surface, which has high requirements and is difficult to process, and is also prone to damage to the tooth. Utility Model Content

[0005] The purpose of the utility model is to overcome the above-mentioned defects or problems existing in the background technology and provide a nut forming combined die.

[0006] In order to achieve the above-mentioned purpose, the present invention and its preferred embodiments adopt the following technical solutions, but the embodiments are not limited to the following solutions:

[0007] Solution 1: A nut forming combined die, comprising:

[0008] The third die is used to shape the front blank into a mushroom head and obtain the third blank; it includes a third lower die and a third upper die; the third lower die is provided with a third groove and a fourth groove, the diameter of the third groove is greater than the diameter of the fourth groove, and the fourth groove opens to the groove bottom of the third groove; the third upper die is provided with a molding surface and a third molding column, and the third molding column protrudes from the molding surface; the molding surface and the third molding column are suitable for extending into the third groove and cooperating with the third groove to shape the mushroom head on the front blank;

[0009] The fourth mold is used to continue shaping the mushroom head of the third blank and obtain a fourth blank; it includes a fourth lower mold and a fourth upper mold, the fourth lower mold is provided with a fifth groove and a sixth groove, the diameter of the fifth groove is greater than the diameter of the sixth groove, and the sixth groove opens at the bottom of the fifth groove; the fourth upper mold includes a third plane, a fourth molding column and a fifth molding column, the two ends of the fourth molding column are respectively connected to the third plane and the fifth molding column, the fourth molding column is truncated cone-shaped and its diameter gradually decreases in the direction close to the fifth molding column; the third plane, the fourth molding column and the fifth molding column are suitable for extending into the fifth groove and cooperating with the fifth groove to continue shaping the mushroom head on the third blank;

[0010] The fifth mold is used to form the wheel rim; it includes a fifth lower mold and a fifth upper mold, the fifth lower mold is provided with a seventh groove and an eighth groove, the diameter of the seventh groove is larger than the diameter of the eighth groove, the eighth groove opens to the bottom of the seventh groove, the fifth upper mold is provided with a fourth plane, the fourth plane is parallel to the bottom of the eighth groove; the fourth plane is suitable for extending into the seventh groove and cooperating with the seventh groove to form the wheel rim.

[0011] Option 2, based on Option 1, the third upper mold is provided with a molding groove, the molding groove is open toward the third lower mold, and the molding groove is truncated cone-shaped and its diameter gradually increases in the direction approaching the third lower mold, and the bottom of the molding groove forms the molding surface.

[0012] Solution three, based on solution one, the side wall of the sixth groove is provided with in-mold bundle teeth, and the fourth mold is also used for forming flower teeth.

[0013] Option 4, based on Options 1 to 3, the third lower die is provided with a first column suitable for positioning the pre-blank, and the first column protrudes from the bottom of the fourth groove; the fourth lower die is provided with a second column suitable for positioning the third blank, and the second column protrudes from the bottom of the sixth groove; the fifth lower die is provided with a third column suitable for positioning the fourth blank, and the third column protrudes from the bottom of the eighth groove.

[0014] Solution five, based on solution four, also includes a countersink mold, which is suitable for forming a countersink on the original blank, and the first column, the second column and the third column are suitable for the countersink to be set to achieve the positioning of the blank.

[0015] Solution 6, based on Solution 5, the countersink mold includes a first mold and a second mold, the first mold is used to shape the original blank and prepare the countersink, and obtain the first blank; it includes a first lower mold and a first upper mold, the first lower mold is provided with a first groove; the first upper mold is provided with a first plane and a first forming column, the first forming column protrudes from the first plane and transitions with the first plane arc surface; the first plane and the first forming column are suitable for extending into the first groove and cooperating with the first groove to prepare the countersink;

[0016] The second die is used to deepen the countersink of the first blank and obtain a second blank; the second die comprises a second lower die and a second upper die, the second lower die is provided with a second groove, the second upper die is provided with a second plane and a second forming column, the second forming column protrudes from the second plane and transitions with the arc surface of the second plane; the second plane and the second forming column are suitable for extending into the second groove and cooperating with the second groove to deepen the countersink;

[0017] The third die is used to shape the inverted second blank into a mushroom head.

[0018] Option seven, based on Option six, the upper end surface of the first column is lower than the bottom of the third groove, the outer diameter of the third molding column is the same as the outer diameter of the first column, and the positions correspond to each other; the upper end surface of the second column is lower than the bottom of the fifth groove, the outer diameter of the fifth molding column is the same as the outer diameter of the second column, and the positions correspond to each other, the fifth molding column is suitable for extending into the sixth groove and being spaced apart from the second column; the third column extends into the seventh groove, and the fifth upper mold is provided with a molding hole, which opens on the fourth plane and is suitable for being sleeved on the outside of the third column to form a through hole.

[0019] From the above description of the utility model and its preferred embodiments, it can be seen that, compared with the prior art, the technical solution of the utility model and its preferred embodiments have the following beneficial effects due to the adoption of the following technical means:

[0020] 1. In scheme 1 and its preferred embodiment,

[0021] A nut forming combined die comprises a third die, a fourth die and a fifth die. The third die is used to form a mushroom head of a pre-formed blank and obtain a third blank. The third die pre-forms the mushroom head to reduce the stress concentration generated by the fourth die, making the process corresponding to the fourth die easier to form and less prone to cracks.

[0022] The fourth mold reserves a large space at the head first, so that in the process corresponding to the fifth mold, the metal of the rim part flows to the surroundings first, and the formed outer chamfer is smaller and almost hidden.

[0023] When used specifically, the front blank is placed in the fourth groove of the third lower die, the third upper die is moved downward, the forming surface of the third upper die and the third forming column extend into the third groove of the third lower die and cooperate with the third groove to form a mushroom head on the front blank, thereby obtaining the third blank;

[0024] The third blank is placed in the sixth groove of the fourth lower die, and the fourth upper die is moved downward. The third plane, the fourth forming column and the fifth forming column of the fourth upper die are suitable for extending into the fifth groove of the fourth lower die, and cooperate with the fifth groove to continue shaping the mushroom head on the third blank to obtain the fourth blank;

[0025] The fourth blank is placed in the eighth groove of the fifth lower die, and the fifth upper die is moved downward. The fourth plane of the fifth upper die extends into the seventh groove of the fifth lower die and cooperates with the seventh groove to form the wheel rim.

[0026] 2. In scheme 2 and its preferred embodiment, the third upper die is provided with a forming groove, which opens toward the third lower die, and is truncated cone-shaped and gradually increases in diameter in the direction approaching the third lower die, so that during forming, the blank is easier to move around, thereby easily forming a mushroom head, and also makes it less likely for oil to swell when pre-forming holes in the next workstation.

[0027] 3. In the third scheme and its preferred embodiment, the side wall of the sixth groove is provided with an in-mold bundled tooth, and the fourth mold is also used to form the flower teeth. Since a small external chamfer is left during the forming process, the subsequent workstation does not need to repair the external chamfer, and the flower teeth at the bottom of the rim will not be squeezed and deformed during processing, and the effective length of the flower teeth will not change. In addition, in the process corresponding to the fifth mold, the metal of the rim part will flow around first, and will not flow downward, nor will it crush the flower teeth.

[0028] 4. In scheme four and its preferred embodiment, the third lower die is provided with a first column suitable for positioning the front blank, and the first column protrudes from the bottom of the fourth groove; the fourth lower die is provided with a second column suitable for positioning the third blank, and the second column protrudes from the bottom of the sixth groove; the fifth lower die is provided with a third column suitable for positioning the fourth blank, and the third column protrudes from the bottom of the eighth groove. After the blank is positioned, it can be processed. It is not easy to move during processing and the position is relatively correct, which is convenient for molding and processing.

[0029] 5. In scheme five and its preferred embodiment, the countersink mold is suitable for forming countersinks on the original blank, and the first column, the second column and the third column are suitable for being provided for the countersink to realize the positioning of the blank, which is simple and convenient.

[0030] 6. In Scheme 6 and its preferred embodiment, the countersink mold includes a first mold and a second mold, the first mold is used to shape the original blank and prepare the countersink to obtain the first blank; it includes a first lower mold and a first upper mold, the first lower mold is provided with a first groove; the first upper mold is provided with a first plane and a first forming column, the first forming column protrudes from the first plane and transitions with the arc surface of the first plane; the first plane and the first forming column are suitable for extending into the first groove and cooperating with the first groove to prepare the countersink; after the pressure of the first plane and the vertical shape of the first groove, the first blank is smoother and convenient for subsequent processing.

[0031] The second mold is used to deepen the countersink of the first blank and obtain the second blank; it includes a second lower mold and a second upper mold, the second lower mold is provided with a second groove, the second upper mold is provided with a second plane and a second forming column, the second forming column protrudes from the second plane and transitions with the arc surface of the second plane; the second plane and the second forming column are suitable for extending into the second groove and cooperating with the second groove to deepen the countersink; the two-step molding process reduces stress and facilitates the subsequent smooth molding of through holes.

[0032] The third mold is used to shape the inverted second blank into a mushroom head. The countersunk hole of the inverted second blank opens downward and can be sleeved on the first column, the second column and the third column to achieve positioning.

[0033] 7. In scheme seven and its preferred embodiment, the upper end surface of the first column is lower than the bottom of the third groove, the outer diameter of the third forming column is the same as the outer diameter of the first column, and the positions correspond to each other, so that a countersunk groove corresponding to the countersunk hole can be formed.

[0034] The upper end surface of the second column is lower than the bottom of the fifth groove. The outer diameter of the fifth forming column is the same as the outer diameter of the second column, and the positions correspond to each other. The fifth forming column is suitable for extending into the sixth groove and is spaced apart from the second column to further deepen the sinking groove, so that the distance between the sinking groove and the sinking hole is closer, which is convenient for subsequent forming of the through hole.

[0035] The third column extends into the seventh groove. The fifth upper mold is provided with a forming hole. The forming hole opens on the fourth plane and is suitable for being sleeved outside the third column to form a through hole.

[0036] Forming the through hole involves five steps, making the process smoother and with less residual stress.

[0037] Furthermore, the third forming column and the fifth forming column participate in the forming of the rim as well as the forming of the through hole, and have multiple functions, thus making the mold simpler and the processing efficiency higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 is a cross-sectional view of the nut in Example 1;

[0040] Figure 2 It is a schematic diagram of the assembly of the comparative example and the object to be fixed;

[0041] Figure 3 This is a schematic diagram of the assembly of the first embodiment and the object to be fixed;

[0042] Figure 4 is a cross-sectional view of the first mold in Example 1;

[0043] Figure 5 is a cross-sectional view of the first blank in Example 1;

[0044] Figure 6 is a cross-sectional view of the second mold in Example 1;

[0045] Figure 7 is a cross-sectional view of the second blank in Example 1;

[0046] Figure 8 is a cross-sectional view of the third mold in Example 1;

[0047] Fig. 9 is a cross-sectional view of the third blank in Example 1;

[0048] Fig.10 is a cross-sectional view of the fourth mold in Example 1;

[0049] Fig.11 is a cross-sectional view of the fourth lower mold in Example 1;

[0050] Fig.12 is a cross-sectional view of the fourth blank in Example 1;

[0051] Fig.13 is a cross-sectional view of the fifth mold in Example 1;

[0052] Fig.14 It is a front view of the nut in the first embodiment;

[0053] Fig.15 This is the processing drawing of the fourth process in Example 1.

[0054] Description of main reference numerals:

[0055] First mold 1; first lower mold 11; first groove 111; first upper mold 12; first plane 121; first molding column 122; second mold 2; second lower mold 21; second groove 211; second upper mold 22; second plane 221; second molding column 222; third mold 3; third lower mold 31, third groove 311, fourth groove 312; first column 313; third upper mold 32; molding groove 321; third molding column 322; fourth mold 4; fourth lower mold 41; fifth groove 411; sixth groove 412; mold interior The bundle tooth 4121; the second column 413; the fourth upper mold 42; the third plane 421; the fourth forming column 422; the fifth forming column 423; the fifth mold 5; the fifth lower mold 51; the seventh groove 511; the eighth groove 512; the third column 513; the fifth upper mold 52; the fourth plane 521; the forming hole 522; the nut 6; the rim 61; the inner chamfer 62; the through hole 63; the countersunk hole 631; the countersunk groove 632; the outer chamfer 64; the flower tooth 65; the first blank 66; the second blank 67; the third blank 68; the fourth blank 69. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are preferred embodiments of the utility model and should not be regarded as excluding other embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0057] In the claims, specification and the above-mentioned drawings of the utility model, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" etc. is to distinguish different objects rather than to describe a specific order.

[0058] In the claims, specification and the above-mentioned drawings of the utility model, unless otherwise explicitly defined, directional words, such as the terms "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise", etc., indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the specific protection scope of the utility model.

[0059] In the claims, specification and the above drawings of the utility model, unless otherwise clearly defined, if the term "fixed connection" or "fixed connection" is used, it should be understood in a broad sense, that is, any connection method without a displacement relationship and relative rotation relationship between the two, that is to say, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements.

[0060] In the claims, specification and drawings of the present utility model, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0061] Embodiment 1

[0062] refer to Figure 1-Figure 14 A nut 6 forming combined mold includes a countersink mold, a third mold 3, a fourth mold 4 and a fifth mold 5.

[0063] In this embodiment, a nut 6 of one size is cited as a reference, so as to compare the advantages of this embodiment over the comparative example when manufacturing nuts 6 of the same size.

[0064] Specifically, refer to Figure 1 The nut 6 includes a rim 61, an inner chamfer 62, a through hole 63 (the hole wall of the through hole 63 has an internal thread), an outer chamfer 64, and a flower tooth 65. The nut 6 includes a circular rim 61 of φ23mm to 24mm. The shape of the rim 61 includes but is not limited to a circle, and can also be a quadrangular, hexagonal, etc. The lower end surface of the rim 61 has a flower tooth 65 that is 13-15mm long and 0.8mm deep from the bottom of the nut 6. Below the inner chamfer 62 is an M10 internal thread with a length of 6-8mm. The size of the internal thread is designed according to the actual application conditions, and M5, M6, etc. can also be used. There is an outer chamfer 64 in the gap between the external flower tooth 65 and the bottom surface of the rim 61. The size of the outer chamfer 64 can be changed by using different processes according to different needs.

[0065] refer to Figure 2 The finished product manufactured by conventional molding method has an outer chamfer 64 size of about R0.8-R1.5. When the nut 6 is riveted, the outer flower teeth 65 are interference-fitted with the fastener to be fastened, and interference occurs at the flower teeth 65. The longitudinal friction force provides a certain torque. However, a large outer chamfer 64 will cause a gap between the nut 6 and the fastener to be fastened, and the lower plane of the rim 61 of the nut 6 cannot completely fit the fastening surface.

[0066] refer to Figure 3 In one implementation method listed in this embodiment, the outer chamfer 64 of the lower end surface of the rim 61 is smaller in size by about R0.04-R0.15, which reduces the gap between the rim 61 and the fastener to be fastened and enhances the sealing ability after being fastened.

[0067] The countersink mold is suitable for forming a countersink 631 on the original blank, and the countersink mold includes a first mold 1 and a second mold 2.

[0068] refer to Figure 4 , Figure 5 The first mold 1 corresponds to the first process, and realizes the preparation and shaping of the countersunk hole 631. The first mold 1 is used to shape the original blank and prepare the countersunk hole 631, and obtain the first blank 66; wherein the original blank is roughly an irregular cylinder. The first mold 1 includes a first lower mold 11 and a first upper mold 12. The first lower mold 11 is provided with a first groove 111, and the first groove 111 is roughly cylindrical. The side wall of the first groove 111 transitions with the arc surface of its groove bottom; the first upper mold 12 is provided with a first plane 121 and a first molding column 122, and the first molding column 122 protrudes from the first plane 121 and transitions with the arc surface of the first plane 121. During processing, the original blank is first placed in the first groove 111, the first upper mold 12 moves downward, the first plane 121 and the first forming column 122 gradually extend into the first groove 111, and the first forming column 122 first presses against the original blank, so that the middle part of the upper side of the original blank is recessed due to the first forming column 122, so as to realize the preliminary forming of the countersunk hole 631, and the countersunk hole 631 eventually becomes a through hole 63 at the fifth mold 5, and the through hole 63 is used to process the internal thread. When the first upper mold 12 continues to move downward, the end surface around the recess becomes flat due to the contact with the first plane 121, and at the same time, during the deformation process of the original blank, the outer wall of the original blank contacts the groove wall of the first groove 111, so as to shape the original blank and obtain the first blank 66. Among them, the reason for the arc surface transition is to make the blank easier to deform, and will not generate large stress to cause cracks, and it is also easy to process the mold.

[0069] refer to Figure 6 , Figure 7The second mold 2 corresponds to the second process. The second mold 2 is used to further shape and deepen the countersunk hole 631 of the first blank 66 to obtain the second blank 67; the second mold 2 includes a second lower mold 21 and a second upper mold 22. The second lower mold 21 is provided with a second groove 211. The side wall of the second groove 211 transitions with the arc surface of its groove bottom; the second upper mold 22 is provided with a second plane 221 and a second molding column 222. The second molding column 222 protrudes from the second plane 221 and transitions with the arc surface of the second plane 221. The distance between the second molding column 222 and the second plane 221 is greater than the distance between the first molding column 122 and the first plane 121, so as to deepen the countersunk hole 631. During processing, the first blank 66 is placed in the second groove 211, the second upper mold 22 moves downward, the second plane 221 and the second forming column 222 gradually extend into the second groove 211, and the second forming column 222 first abuts against the countersunk hole 631 of the first blank 66 to further deepen the countersunk hole 631 until the second plane 221 abuts against the upper end surface of the first blank 66, so that the upper end surface of the first blank 66 becomes flat (the upper end surface of the first blank 66 may become uneven after deformation), and the second blank 67 is obtained. Through multiple processes, the subsequent forming of the through hole 63 can be smoother.

[0070] refer to Figure 8 , Fig. 9, the third mold 3 corresponds to the third process, and the third mold 3 is used to shape the inverted second blank 67 into a mushroom head (prepared for the rim 61), and obtain the third blank 68. The third mold 3 includes a third lower mold 31 and a third upper mold 32; the third lower mold 31 is provided with a third groove 311, a fourth groove 312 and a first column 313, the diameter of the third groove 311 is greater than the diameter of the fourth groove 312, the fourth groove 312 opens at the bottom of the third groove 311, the first column 313 protrudes from the bottom of the fourth groove 312 and the upper end surface is lower than the bottom of the third groove 311, and the first column 313 can be sleeved on the countersunk hole 631 to achieve positioning; the third upper mold 32 is provided with a molding groove 321 and a third molding column 322, the molding groove 321 opens toward the third lower mold 31, and the molding groove 321 is truncated cone-shaped and its diameter gradually increases in the direction close to the third lower mold 31, the bottom of the molding groove 321 forms a molding surface, and the third molding column 322 protrudes from the molding surface During processing, the fourth groove 312 is mainly used to position the second blank 67, and the third groove 311 is mainly used to form a mushroom head. Specifically, the second blank 67 is inverted so that the countersunk hole 631 of the second blank 67 is sleeved on the first column 313, and the third upper mold 32 descends, and the molding groove 321 and the third molding column 322 extend into the third groove 311, wherein the third molding column 322 first abuts against the upper end of the second blank 67, so that the metal at the upper end of the second blank 67 flows toward the groove wall of the third groove 311 (i.e., to the surroundings). At the same time, since the molding groove 321 is truncated cone-shaped and its diameter gradually increases in the direction close to the third lower mold 31, the groove wall guidance of the molding groove 321 also facilitates the metal to flow to the surroundings, and finally forms a mushroom head, and obtains the third blank 68. In this process, since the third forming column 322 protrudes from the bottom of the forming groove 321, and the outer diameter of the third forming column 322 is the same as the outer diameter of the first column 313, and the positions correspond to each other, a sink groove 632 of the same size as the sink hole 631 is also formed on the other side of the countersunk hole 631, which is convenient for the subsequent penetration of the sink groove 632 and the countersunk hole 631, thereby forming a through hole 63. The top of the third blank 68 is inclined downward from the notch of the sink groove 632 to the surrounding areas. The third mold 3 pre-forms the mushroom head, and the fourth mold 4 shapes the mushroom head, which apportions the deformation when forming the mushroom head. Compared with the direct forming of the fourth mold 4, this method can reduce the stress concentration generated by the fourth mold 4, making the next process easier to form and less prone to cracks.

[0071] Among them, the forming groove 321 and the third forming column 322 can be formed as one piece, and can also be formed by assembling a punch tube and a punch rod. Specifically, the punch tube is provided with a forming groove 321 and a mounting hole, the mounting hole is opened at the bottom of the forming groove 321, the punch rod is placed in the mounting hole and extends into the forming groove 321 to form the third forming column 322.

[0072] refer to Figure 10-12The fourth mold 4 corresponds to the fourth process. The fourth mold 4 is used to continue to shape the mushroom head of the third blank 68 and form the flower teeth 65, and obtain the fourth blank 69; the fourth mold 4 includes a fourth lower mold 41 and a fourth upper mold 42. The fourth lower mold 41 is provided with a fifth groove 411, a sixth groove 412 and a second column 413. The diameter of the fifth groove 411 is greater than the diameter of the sixth groove 412. The sixth groove 412 opens at the bottom of the fifth groove 411. The side wall of the sixth groove 412 is provided with an in-mold bundle tooth 4121; the second column 413 protrudes from the bottom of the sixth groove 412 and the upper end surface is lower than the bottom of the fifth groove 411. The second column 413 can be provided with a countersunk hole 631 The fourth upper die 42 includes a third plane 421, a fourth molding column 422 and a fifth molding column 423. The two ends of the fourth molding column 422 are connected to the third plane 421 and the fifth molding column 423 respectively. The fourth molding column 422 is truncated and its diameter gradually decreases in the direction close to the fifth molding column 423. The outer diameter of the fifth molding column 423 is the same as the outer diameter of the second column 413, and the positions correspond to each other. The fifth molding column 423 is suitable for extending into the sixth groove 412 and is spaced from the second column 413. During processing, the fifth groove 411 is mainly used to continue shaping the mushroom head, and the sixth groove 412 is mainly used to form the flower teeth 65. The countersunk hole 631 of the third blank 68 is sleeved on the second column 413 to achieve the positioning of the third blank 68. Then the fourth upper die 42 moves downward, the fifth molding column 423 abuts against the countersunk groove 632 and flows to the surroundings under the action of the inclined surface of the fourth molding column 422. The part of the third blank 68 located in the fifth groove 411 further forms a mushroom head. The outer wall of the third blank 68 located at the sixth groove 412 flows downward from top to bottom to form the flower teeth 65, and obtains the fourth blank 69, which is roughly Y-shaped, and the top of the fourth blank 69 is inclined upward from the notch of the sinking groove 632. In this process, since the outer diameter of the fifth forming column 423 is the same as the outer diameter of the second column 413, and the positions correspond to each other, the fifth forming column 423 continues to deepen the sinking groove 632, which is convenient for the subsequent sinking groove 632 and the countersunk hole 631 to penetrate, thereby forming the through hole 63.

[0073] In order to reduce the outer chamfer 64 after forming, a larger space is reserved at the head in the fourth process (the mushroom head formed by the fourth forming column 422 and the fifth groove 411 has a large slope), so that in the next process, the metal of the rim 61 flows to the surroundings first, referring to Fig.15When the teeth are bundled, the top of the tooth is inclined 78° to the first chamfer level, and the rim 61 sinks 165° to the first chamfer level. The first chamfer between the rim 61 and the top of the tooth is R2.0 (the purpose is to cooperate with the rounded corner transition of the next process, and the specific size is not defined). When the rim 61 is finally formed, this design will fold inward at the first chamfer, so that the formed outer chamfer 64 is smaller and almost hidden. During forming, the second chamfer fits with the mold of the next process, so that the next process will not damage the flower tooth 65; because the fourth process reserves a large space at the head first, the position of the rim 61 will be bent downward under force when it reaches the fifth station, so it will fit the mold better.

[0074] refer to Fig.13 , Fig.14 The fifth mold 5 corresponds to the fifth process. The fifth mold 5 is used to form the rim 61 and trim the bottom of the flower tooth 65 and the through hole 63 to obtain the nut; the fifth mold 5 includes a fifth lower mold 51 and a fifth upper mold 52. The fifth lower mold 51 is provided with a seventh groove 511, an eighth groove 512 and a third column 513. The diameter of the seventh groove 511 is greater than the diameter of the eighth groove 512. The eighth groove 512 opens at the bottom of the seventh groove 511. The seventh groove 511 is mainly used to form the rim 61. The eighth groove 512 is mainly used to trim the bottom of the flower tooth 65. The third column 513 protrudes from the bottom of the eighth groove 512 and extends into the seventh groove 511. It is mainly used to form the through hole 63. The third column 513 can be set on the countersunk hole 631 to achieve positioning. The fifth upper die 52 is provided with a fourth plane 521 and a forming hole 522. The forming hole 522 opens on the fourth plane 521 and is suitable for being sleeved outside the third column 513. The fourth plane 521 is parallel to the bottom of the eighth groove 512, that is, the bottom of the eighth groove 512 is also a plane, so that the upper and lower ends of the rim 61 can be flat. During processing, the countersunk hole 631 of the fourth blank 69 is first inserted on the third column 513 to achieve positioning, and then the fifth upper die 52 moves downward, and the fourth plane 521 presses the mushroom head until the bottom of the mushroom head abuts against the plane of the bottom of the seventh groove 511. In this process, the third column 513 cooperates with the forming hole 522 to achieve punching, and the through hole 63 is formed. Thus, a nut is obtained. Since a smaller outer chamfer 64 is left during molding, the subsequent station does not need to repair the outer chamfer 64, and the phenomenon of the flower tooth 65 at the bottom of the rim 61 being squeezed and deformed during processing will not occur, and the effective length of the flower tooth 65 will not change. In the process corresponding to the fifth mold 5 , the metal of the rim 61 flows to the surroundings first, and does not flow downward, nor does it crush the teeth 65 .

[0075] In this embodiment, the third lower die 31 is provided with a first column 313 suitable for positioning the pre-blank, and the first column 313 protrudes from the bottom of the fourth groove 312; the fourth lower die 41 is provided with a second column 413 suitable for positioning the third blank 68, and the second column 413 protrudes from the bottom of the sixth groove 412; the fifth lower die 51 is provided with a third column 513 suitable for positioning the fourth blank 69, and the third column 513 protrudes from the bottom of the eighth groove 512. After the blank is positioned, it can be processed. It is not easy to move during processing and the position is relatively correct, which is convenient for molding and processing.

[0076] In this embodiment, the upper end surface of the first column 313 is lower than the bottom of the third groove 311, the outer diameter of the third molding column 322 is the same as the outer diameter of the first column 313, and the positions correspond to each other, so that the sink groove 632 corresponding to the countersunk hole 631 can be formed. The upper end surface of the second column 413 is lower than the bottom of the fifth groove 411, the outer diameter of the fifth molding column 423 is the same as the outer diameter of the second column 413, and the positions correspond to each other. The fifth molding column 423 is suitable for extending into the sixth groove 412 and is spaced from the second column 413 to further deepen the sink groove 632, so that the distance between the sink groove 632 and the countersunk hole 631 is closer, which is convenient for the subsequent molding of the through hole 63; the third column 513 extends into the seventh groove 511, and the fifth upper mold 52 is provided with a molding hole 522, which opens on the fourth plane 521 and is suitable for being sleeved outside the third column 513 to mold the through hole 63. The molding of the through hole 63 is realized through five steps, so that the molding of the through hole 63 is smoother and the residual stress is smaller. Furthermore, the third forming column 322 and the fifth forming column 423 participate in the forming of the rim 61 as well as the forming of the through hole 63 , and have multiple functions, thus making the mold simpler and the processing efficiency higher.

[0077] The molding of the flower teeth 65 can be achieved by using the above-mentioned mold without rolling, thereby reducing the processing cost.

[0078] Compared with the prior art, this application has the following beneficial effects:

[0079] In the prior art, according to the conventional molding method, the mushroom head is prepared in the fourth process, and the rim 61 is directly formed in the fifth process. However, due to the large deformation and stress concentration caused by the conventional method, cracks in the rim 61 are easily generated from the beginning of the deformation of the rim 61. The cracks gradually intensify in the subsequent processes. Therefore, the present application adopts the third process to prepare the rim 61.

[0080] In the prior art, the conventional design of pre-processing the flower teeth 65 at the fourth station will leave a large outer chamfer 64 during molding, which will affect the sealing. If the outer chamfer 64 position needs to be repaired at a subsequent station, that is, the contact surface between the mold and the bottom of the rim 61 is sharpened, it will not only greatly reduce the life of the mold, but also cause the flower teeth 65 at the bottom of the rim 61 to be squeezed and deformed during processing, resulting in a shortened effective length of the flower teeth 65. Therefore, it is improved to reserve a larger space for the rim 61 at the fourth station, and the transition between the flower teeth 65 and the bottom of the rim 61 adopts a multi-angle and rounded design. This allows the metal of the rim 61 to flow outward more smoothly when the teeth are bundled, and will not flow downward to crush the flower teeth 65.

[0081] Of course, in other embodiments, the flower teeth 65 may not be formed in the fourth step, and the processing may be performed after the fifth step is completed.

[0082] Embodiment 2

[0083] A nut cold forging method is provided, which is based on the above-mentioned nut forming combined die to cold forge a nut 6; the method specifically comprises the following steps:

[0084] The original blank is placed in the first groove 111 of the first lower mold 11, and the first upper mold 12 is moved downward, and the first plane 121 and the first forming column 122 of the first upper mold 12 extend into the first groove 111 and cooperate with the first groove 111 to prepare the forming counterbore 631, thereby obtaining the first blank 66;

[0085] The first blank 66 is placed in the second groove 211 of the second lower mold 21, and the second upper mold 22 is moved downward. The second plane 221 and the second molding column 222 of the second upper mold 22 extend into the second groove 211 and cooperate with the second groove 211 to deepen the countersunk hole 631 of the first blank 66, thereby obtaining a second blank 67;

[0086] The countersunk hole 631 of the inverted second blank 67 is sleeved on the first column 313, and the second blank 67 is placed in the fourth groove 312 of the third lower die 31, and the third upper die 32 is moved downward, and the molding surface of the third upper die 32 and the third molding column 322 are suitable for extending into the third groove 311 of the third lower die 31 and cooperating with the third groove 311 to form a mushroom head and the countersunk groove 632 on the second blank 67, thereby obtaining a third blank 68;

[0087] The countersunk hole 631 of the third blank 68 is sleeved on the second column 413, and the third blank 68 is placed in the sixth groove 412 of the fourth lower die 41, and the fourth upper die 42 is moved downward, and the third plane 421, the fourth forming column 422 and the fifth forming column 423 of the fourth upper die 42 are suitable for extending into the fifth groove 411 of the fourth lower die 41, and cooperate with the fifth groove 411 to continue shaping the mushroom head on the third blank 68 and deepen the countersunk groove 632, so as to obtain the fourth blank 69;

[0088] The countersunk hole 631 of the fourth blank 69 is sleeved on the third column 513, and the fourth blank 69 is placed in the eighth groove 512 of the fifth lower mold 51, and the fifth upper mold 52 is moved downward, and the fourth plane 521 of the fifth upper mold 52 extends into the seventh groove 511 of the fifth lower mold 51 and cooperates with the seventh groove 511 to form the rim 61; and the forming hole 522 is sleeved outside the third column 513 to connect the countersunk groove 632 and the countersunk hole 631 to form the through hole 63.

[0089] The description of the above specification and embodiments is used to explain the protection scope of the utility model, but does not constitute a limitation on the protection scope of the utility model. Through the enlightenment of the utility model or the above embodiments, ordinary technicians in this field can obtain modifications, equivalent replacements or other improvements to the embodiments of the utility model or part of the technical features thereof through logical analysis, reasoning or limited experiments, which should be included in the protection scope of the utility model.

Claims

1. A nut forming combined die, characterized in that: include The third die (3) is used to shape the front blank into a mushroom head and obtain the third blank (68); it comprises a third lower die (31) and a third upper die (32); the third lower die (31) is provided with a third groove (311) and a fourth groove (312); the diameter of the third groove (311) is greater than the diameter of the fourth groove (312), and the fourth groove (312) opens at the groove bottom of the third groove (311); the third upper die (32) is provided with a shaping surface and a third shaping column (322), and the third shaping column (322) protrudes from the shaping surface; the shaping surface and the third shaping column (322) are suitable for extending into the third groove (311) and cooperating with the third groove (311) to shape the mushroom head on the front blank; The fourth mold (4) is used to further shape the mushroom head of the third blank (68) to obtain a fourth blank (69); the fourth mold (4) comprises a fourth lower mold (41) and a fourth upper mold (42); the fourth lower mold (41) is provided with a fifth groove (411) and a sixth groove (412); the diameter of the fifth groove (411) is greater than the diameter of the sixth groove (412); the sixth groove (412) opens at the bottom of the fifth groove (411); the fourth upper mold (42) comprises a third plane (421), a fourth molding column (422) and a fifth molding column (423), wherein two ends of the fourth molding column (422) are respectively connected to the third plane (421) and the fifth molding column (423); the fourth molding column (422) is truncated cone-shaped and its diameter gradually decreases in a direction approaching the fifth molding column (423); the third plane (421), the fourth molding column (422) and the fifth molding column (423) are suitable for extending into the fifth groove (411) and cooperating with the fifth groove (411) on the third blank (68) to continue shaping the mushroom head; The fifth mold (5) is used for molding a wheel rim (61); it comprises a fifth lower mold (51) and a fifth upper mold (52); the fifth lower mold (51) is provided with a seventh groove (511) and an eighth groove (512); the diameter of the seventh groove (511) is greater than the diameter of the eighth groove (512); the eighth groove (512) opens at the groove bottom of the seventh groove (511); the fifth upper mold (52) is provided with a fourth plane (521); the fourth plane (521) is parallel to the groove bottom of the eighth groove (512); the fourth plane (521) is suitable for extending into the seventh groove (511) and cooperating with the seventh groove (511) to mold the wheel rim (61).

2. A nut forming combined die as claimed in claim 1, characterized in that: The third upper die (32) is provided with a molding groove (321), the molding groove (321) is open toward the third lower die (31), and the molding groove (321) is truncated cone-shaped and its diameter gradually increases in a direction approaching the third lower die (31), and the bottom of the molding groove (321) forms the molding surface.

3. A nut forming combined die as claimed in claim 1, characterized in that: The side wall of the sixth groove (412) is provided with an in-mold bundled tooth (4121), and the fourth mold (4) is also used for forming the flower tooth (65).

4. A nut forming combined die according to any one of claims 1 to 3, characterized in that: The third lower die (31) is provided with a first column (313) suitable for positioning the pre-blank, and the first column (313) protrudes from the bottom of the fourth groove (312); the fourth lower die (41) is provided with a second column (413) suitable for positioning the third blank (68), and the second column (413) protrudes from the bottom of the sixth groove (412); the fifth lower die (51) is provided with a third column (513) suitable for positioning the fourth blank (69), and the third column (513) protrudes from the bottom of the eighth groove (512).

5. A nut forming combined die as claimed in claim 4, characterized in that: It also includes a countersink die, which is suitable for forming a countersink (631) on the original blank. The first column (313), the second column (413) and the third column (513) are suitable for being fitted around the countersink (631) to achieve blank positioning.

6. A nut forming combined die as claimed in claim 5, characterized in that: The countersink die comprises a first die (1) and a second die (2), the first die (1) being used for shaping an original blank and preparing a countersink (631) to obtain a first blank (66); the first die (11) comprising a first lower die (11) and a first upper die (12), the first lower die (11) being provided with a first groove (111); the first upper die (12) being provided with a first plane (121) and a first forming column (122), the first forming column (122) protruding from the first plane (121) and transitioning with the first plane (121) in an arcuate surface; the first plane (121) and the first forming column (122) are suitable for extending into the first groove (111) and cooperating with the first groove (111) to prepare for forming the countersink (631); The second mold (2) is used to deepen the countersunk hole (631) of the first blank (66) and obtain a second blank (67); it comprises a second lower mold (21) and a second upper mold (22); the second lower mold (21) is provided with a second groove (211); the second upper mold (22) is provided with a second plane (221) and a second molding column (222); the second molding column (222) protrudes from the second plane (221) and transitions with the second plane (221) in an arc surface; the second plane (221) and the second molding column (222) are suitable for extending into the second groove (211) and cooperating with the second groove (211) to deepen the countersunk hole (631); The third mold (3) is used to shape the inverted second blank (67) into a mushroom head.

7. A nut forming combined die as claimed in claim 6, characterized in that: The upper end surface of the first column (313) is lower than the bottom of the third groove (311), the outer diameter of the third molding column (322) is the same as the outer diameter of the first column (313), and the positions correspond to each other; the upper end surface of the second column (413) is lower than the bottom of the fifth groove (411), the outer diameter of the fifth molding column (423) is the same as the outer diameter of the second column (413), and the positions correspond to each other, the fifth molding column (423) is suitable for extending into the sixth groove (412) and is spaced apart from the second column (413); the third column (513) extends into the seventh groove (511), and the fifth upper mold (52) is provided with a molding hole (522), the molding hole (522) opens on the fourth plane (521) and is suitable for being sleeved outside the third column (513) to form a through hole (63).

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