A forging die for a hollow shaft and a flat forging machine for a hollow shaft

Abstract

The utility model provides a kind of forging press die for hollow shaft and is used for the flat forging machine of hollow shaft, it is related to forging press die field, the scheme using is as follows: including die body, the die body is along its axial setting and is forged and pressed hole, the hole bottom of the forging and pressed hole can be with blank end surface abut, coaxially be provided with mandrel in the forging and pressed hole, the end of the mandrel protrudes the forging and pressed hole, the mandrel with the die body is integrated structure, when forging, the mandrel can be inserted into blank inner hole. The utility model can support the inner hole of blank of hollow structure during forging process, realize the control to inner hole deformation, avoid finished product to produce shrink neck and other deformation conditions, it is favorable to promote production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of forging dies, and in particular to a forging die for hollow shafts and a flat forging machine for hollow shafts. Background Technology

[0002] Hollow shafts are commonly used components. With a hollow core, they require less material and are lighter than solid shafts for the same outer diameter and length. This is advantageous for equipment with strict weight requirements. The hollow structure increases the moment of inertia of the shaft's cross-section. Under the same external force, the bending deformation of a hollow shaft is smaller than that of a solid shaft, allowing it to better maintain its shape and stability. This makes it suitable for applications subject to large bending moments, such as machine tool spindles and automotive drive shafts. Furthermore, the hollow structure facilitates airflow, improving the shaft's heat dissipation performance.

[0003] In the commercial vehicle sector, hollow half-shafts are mostly manufactured using the following series of processes: 1) Flange pretreatment process: pre-upsetting → rolling → drilling center hole → clamping → cutting → machining end face and inner hole; 2) Shaft tube process: Cutting → Heating → Die forging → Inspection → Grinding → Shot blasting; 3) Hollow half-shaft process: friction welding → end face machining and chamfering → shaft machining → tempering → rough straightening → shot blasting → rough flange machining → finish machining → knurling → medium frequency induction hardening → tempering → shot blasting → fine straightening → finish machining → drilling → flaw detection → cleaning → inspection and marking → packaging and warehousing.

[0004] During the forging process of shaft tubes, the mold used cannot support the interior of the hollow billet. During the deformation process, the internal deformation of the billet is difficult to control, which can easily lead to internal deformation, resulting in inconsistent inner diameters of the product parts, causing problems such as reduced diameter and poor straightness. This increases the allowance for subsequent machining and reduces production efficiency. Utility Model Content

[0005] To address the technical problem of low forging efficiency caused by the disassembly and assembly of split molds in the forging of long hollow shafts in the prior art, this utility model provides a forging die for hollow shafts and a flat forging machine for hollow shafts. During the forging process, the inner hole of the hollow structure billet is supported, thereby controlling the deformation of the inner hole and avoiding deformation such as necking, which helps to improve production efficiency.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is: a forging die for hollow shafts, including a die body, a forging hole provided along its axial direction, the bottom of the forging hole being able to abut against the end face of the blank, a mandrel being coaxially arranged inside the forging hole, the diameter of the mandrel being larger than the inner diameter of the corresponding blank, the end of the mandrel extending out of the forging hole, the mandrel and the die body being an integral structure, and during forging, the mandrel being able to extend into the inner hole of the blank.

[0007] This invention, by setting a mandrel inside the forging die, can support the inner hole of the billet during forging, control the deformation of the inner hole, avoid deformation problems such as inner hole shrinkage and poor straightness, reduce subsequent machining allowance, reduce subsequent machining steps, and help improve production efficiency.

[0008] Furthermore, the mandrel has a tapered structure, with its thicker end connected to the bottom of the forging hole and its thinner end extending out of the forging hole.

[0009] This invention facilitates demolding by using a conical mandrel.

[0010] Furthermore, the taper of the mandrel is a, where 1:10 ≤ a ≤ 1:5.

[0011] Furthermore, the forging hole is a tapered hole, with the coarse end of the forging hole close to the fine end of the mandrel.

[0012] This invention utilizes a tapered forging hole to facilitate the smooth entry of the blank into the forging hole.

[0013] Furthermore, the taper of the forging hole is b, where 1:10 ≤ b ≤ 1:5.

[0014] Furthermore, a mounting shaft is coaxially provided at one end of the mold body, and the mounting shaft is used for detachable connection with the flat forging machine body.

[0015] Furthermore, a high-temperature resistant protective layer is provided on the wall of the forging hole and on the outer circular surface of the mandrel.

[0016] This invention protects the mold by setting a high-temperature resistant protective layer, which has a good heat insulation and cooling effect on the mold and extends the service life of the mold.

[0017] Furthermore, the high-temperature resistant protective layer is made of forged graphite emulsion material.

[0018] This invention uses forged graphite emulsion material as a high-temperature resistant protective layer, which facilitates demolding of forgings and improves the quality and surface finish of forgings.

[0019] This utility model also provides a flat forging machine for hollow shafts, including a flat forging machine body and three forging dies for hollow shafts arranged side by side. The forging dies for hollow shafts are horizontally and movably mounted on the flat forging machine body. The three forging dies for hollow shafts are, in order, die one, die two, and die three. Die one is used for pre-forging one end of the billet, die two is used for final forging one end of the pre-forged billet, and die three is used for final forging the other end of the billet. The mandrel length of die one is greater than that of die two, and the forging hole depth of die one is greater than that of die two. Die two and die three have the same structure, and the mandrel diameters of die one, die two, and die three are all the same.

[0020] This invention enables pre-forging and final forging of one or both ends of a billet by setting multiple molds on the body of the flat forging machine, thereby improving forging accuracy, reducing subsequent machining steps, and increasing production efficiency.

[0021] Furthermore, it also includes a pushing mold, which includes a pushing disk and a mounting shaft arranged coaxially. The pushing mold is horizontally and movably arranged on the body of the flat forging machine, and the pushing mold and the second mold are symmetrically arranged on both sides of the third mold.

[0022] This invention facilitates the removal of flash generated during forging by setting up a pushing mold.

[0023] As can be seen from the above technical solutions, this utility model has the following advantages: This utility model provides a forging die for hollow shafts and a flat forging machine for hollow shafts. By setting a mandrel inside the forging die, the inner hole of the billet can be supported during forging, controlling the deformation of the inner hole and avoiding deformation problems such as inner hole shrinkage and poor straightness. This reduces the subsequent machining allowance and machining steps, which is conducive to improving production efficiency. The conical mandrel facilitates demolding. The conical forging hole facilitates the smooth entry of the billet into the forging hole. The high-temperature resistant protective layer protects the die, providing good heat insulation and cooling, and extending the service life of the die. Using forged graphite emulsion as a high-temperature resistant protective layer facilitates demolding of the forging, improving the quality and surface finish of the forging. By setting multiple dies on the flat forging machine body, pre-forging and final forging of one or both ends of the billet can be achieved, improving forging accuracy, reducing subsequent machining steps, and improving production efficiency. The push die facilitates the removal of flash generated during forging. Attached Figure Description

[0024] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a structural diagram of a specific embodiment of the present invention. Figure 1 .

[0026] Figure 2 This is a structural diagram of a specific embodiment of the present invention. Figure 2 .

[0027] Figure 3 This is a partial structural diagram of a specific embodiment two of the present utility model.

[0028] Figure 4 This is a schematic diagram of the lower concave mold in the second specific embodiment of this utility model.

[0029] In the diagram, 1. Die body; 2. Mandrel; 3. High-temperature resistant protective layer; 4. Mounting shaft; 5. Upper die; 6. Flat forging machine body; 7. Lower die; 8. Die one; 9. Die two; 10. Die three; 11. Pushing die; 12. Semicircular groove; 13. Flash groove; 14. Forging hole. Detailed Implementation

[0030] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent. Specific Implementation Method 1 like Figure 1 and Figure 2 As shown in the figure, this specific embodiment provides a forging die for a hollow shaft, including a die body 1. The die body 1 is provided with a forging hole 14 along its axial direction. The bottom of the forging hole 14 can abut against the end face of the blank. A mandrel 2 is coaxially arranged in the forging hole 14. The diameter of the mandrel 2 is larger than the inner diameter of the corresponding blank. The end of the mandrel 2 extends out of the forging hole 14. The mandrel 2 and the die body 1 are integrally cast. During forging, the mandrel 2 can extend into the inner hole of the blank.

[0032] This specific embodiment, by setting a mandrel 2 inside the forging die, can support the inner hole of the billet during forging, control the deformation of the inner hole, avoid deformation problems such as inner hole shrinkage and poor straightness, reduce subsequent machining allowance, reduce subsequent machining steps, and help improve production efficiency.

[0033] like Figure 1 As shown, to facilitate demolding, in this specific embodiment, the mandrel 2 has a tapered structure. The thick end of the mandrel 2 is connected to the bottom of the forging hole 14, and the thin end of the mandrel 2 extends out of the forging hole 14. The taper of the mandrel 2 is a, 1:10≤a≤1:5. Its taper cannot be greater than the design tolerance of the taper of the half shaft. In this specific embodiment, the taper a is 1:5.

[0034] like Figure 1 As shown, in order to facilitate the entry of the blank into the mold, the forging hole 14 is a tapered hole, the coarse end of the forging hole 14 is close to the fine end of the mandrel 2, and the taper of the forging hole 14 is b, 1:10≤b≤1:5. In this specific embodiment, the taper b is 1:5.

[0035] To facilitate the installation of this mold, a mounting shaft 4 is coaxially provided at one end of the mold body 1. The mounting shaft 4 is used to detachably connect with the flat forging machine body 6. In this specific embodiment, both the mold body 1 and the mounting shaft 4 are made of hot work die steel.

[0036] like Figure 1 and Figure 2 As shown, in order to protect the mold, in this specific embodiment, a high-temperature resistant protective layer 3 is provided on the wall of the forging hole 14 and the outer circular surface of the mandrel 2; by providing the high-temperature resistant protective layer 3, the mold can be protected, and the mold has a good heat insulation and cooling effect, thus extending the service life of the mold; furthermore, the high-temperature resistant protective layer is made of forged graphite emulsion material. By using forged graphite emulsion material as the high-temperature resistant protective layer 3, it is easier to demold the forging, and the quality and surface finish of the forging can be improved.

[0037] like Figure 1 and Figure 2 As shown, it can be understood that the axial dimensions of the forging hole 14 and the mandrel 2, as well as the protrusion dimension of the mandrel 2, are determined according to the design requirements of the hollow shaft. Specific Implementation Method Two like Figure 3As shown, this specific embodiment also provides a flat forging machine for hollow shafts, including a flat forging machine body 6, and three forging dies for hollow shafts arranged side by side according to Specific Embodiment 1. The forging dies for hollow shafts are horizontally and movably arranged on the flat forging machine body 6. The forging dies for hollow shafts can move towards the end of the billet. The three forging dies for hollow shafts are, in order, die one 8, die two 9, and die three 10. Die one 8 is used for pre-forging one end of the billet, die two 9 is used for final forging one end of the pre-forged billet, and die three 10 is used for final forging the other end of the billet. The length of the mandrel 2 of die one 8 is greater than the length of the mandrel 2 of die two 9, and the depth of the forging hole 14 of die one 8 is greater than the depth of the forging hole 14 of die two 9. The structures of die two 9 and die three 10 are the same, and the diameters of the mandrel 2 of die one 8, die two 9, and die three 10 are all the same.

[0039] Since the billet is forged in one go, the deformation of the billet is large, which affects the accuracy. Therefore, in this specific embodiment, multiple molds are set on the body 6 of the flat forging machine to realize the pre-forging and final forging of one or both ends of the billet, improve the forging accuracy, reduce the subsequent machining steps, and improve production efficiency.

[0040] like Figure 3 and Figure 4 As shown, forging produces flash. In this specific embodiment, it also includes a push die 11, which includes a push disk and a mounting shaft 4 coaxially arranged. The push die 11 is horizontally and movably arranged on the flat forging machine body 6. The push die 11 and the second die 9 are symmetrically arranged on both sides of the third die 10. The flat forging machine body 6 also includes a die cavity, which includes an upper die cavity 5 and a lower die cavity 7. The lower die cavity 7 is mounted on the bed and does not move during operation. The upper die cavity 5 is mounted on the clamping slide and moves up and down with the clamping slide. In this specific embodiment... The lower die 7 is provided with four semi-circular grooves for accommodating the billet during forging. The radius of the semi-circular groove corresponding to the push die 11 is larger than that of the other semi-circular grooves 12, which enables the billet to move axially. The semi-circular groove corresponding to the push die 11 is also provided with two flash grooves 13. The two flash grooves 13 are symmetrically located on both sides of the semi-circular groove 12 to accommodate the flash generated during forging. Combined with the horizontal movement of the push die 11, the billet is driven to move axially within the corresponding semi-circular groove 12, which can separate the flash from the forged billet and achieve the trimming of the two ends of the billet.

[0041] In this specific embodiment, the flat forging machine body 6 is a commercially available 500T flat forging machine, and is equipped with an electromagnetic mold installation system, which can disassemble and assemble mold 1 8, mold 2 9, mold 3 10 and mold 4 through electromagnets. The electromagnetic mold installation system is equipped with a backup power supply to improve safety. The flat forging machine body 6 is existing technology, and its structure and working process will not be described in detail.

[0042] The working process of this flat forging machine used for hollow shafts is as follows: S01: Heating, using a medium-frequency electric furnace to heat one end of the billet; S02: One-time pre-forging, using die-8 of a 500t flat forging machine to perform one-time pre-forging on the heating end of the billet, the horizontal stroke of die-8 in one-time pre-forging is 77 mm; S03: First final forging, the pre-forged billet is moved laterally, and the pre-forged end of the billet is forged once using the die 29 of the 500t flat forging machine. The horizontal stroke of the first final forging die 29 is 21 mm. S04: First trimming, the billet after final forging is moved axially to the corresponding semi-circular groove 12 so that the flash enters the flash groove 13. The push die 11 of the 500t flat forging machine is used to trim the part after final forging once. The horizontal stroke of the push die 11 is 21 mm. S05: Cooling, placing the cut part in the air for natural cooling; S06: Heating. After the first edge has completely cooled down, heat the other end. S07: Secondary final forging, the billet is rotated 180° and the unforged end is forged using die 310 of a 500t flat forging machine. The stroke of die 310 during final forging is 23 mm. S08: Secondary edge trimming. The part after secondary final forging is placed into the semi-circular groove 12 corresponding to the push die 11, and the push die 11 of the 500t flat forging machine is used for secondary edge trimming. The stroke of the push die 11 is 20 mm. S09: Cooling, place the part with the second-cut edges in the air for natural cooling.

[0043] In this specific embodiment, since the mounting components at both ends of the hollow shaft are different and the precision requirements are different, one end needs to be pre-forged and final-forged once. The final forging can correct the deviation at the hole of the hollow shaft during the first pre-forging and improve the forging precision. The other end has lower precision requirements and can be forged directly into place through a second final forging. If both ends have high precision requirements, pre-forging and final forging are performed at both ends respectively.

[0044] As can be seen from the above specific embodiments, this utility model has the following beneficial effects: 1. By setting a mandrel 2 inside the forging die, the inner hole of the billet can be supported during forging, the deformation of the inner hole can be controlled, and deformation problems such as inner hole shrinkage and poor straightness can be avoided. This reduces the subsequent machining allowance and the number of subsequent machining steps, which is conducive to improving production efficiency. 2. The use of a conical mandrel 2 facilitates demolding; 3. The forging hole 14 with a conical structure facilitates the smooth entry of the billet into the forging hole 14; 4. By setting a high-temperature resistant protective layer 3, the mold can be protected, which has a good heat insulation and cooling effect on the mold and extends the service life of the mold; 5. Using forged graphite emulsion as a high-temperature resistant protective layer can facilitate demolding of forgings, improve forging quality and surface finish; 6. By setting multiple dies on the flat forging machine body, pre-forging and final forging of one or both ends of the billet can be achieved, improving forging accuracy, reducing subsequent machining steps, and improving production efficiency; 7. The push mold 11 is set to facilitate the removal of flash generated during forging.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A forging die for a hollow shaft, comprising a die body (1), characterized in that, The mold body (1) is provided with a forging hole (14) along its axial direction. The bottom of the forging hole (14) can abut against the end face of the blank. A mandrel (2) is coaxially arranged inside the forging hole (14). The diameter of the mandrel (2) is larger than the inner diameter of the corresponding blank. The end of the mandrel (2) extends out of the forging hole (14). The mandrel (2) and the mold body (1) are an integral structure. During forging, the mandrel (2) can extend into the inner hole of the blank.

2. The forging die for hollow shafts as described in claim 1, characterized in that, The mandrel (2) has a tapered structure. The thick end of the mandrel (2) is connected to the bottom of the forging hole (14), and the thin end of the mandrel (2) extends out of the forging hole (14).

3. The forging die for hollow shafts as described in claim 2, characterized in that, The taper of the mandrel (2) is a, where 1:10≤a≤1:

5.

4. The forging die for hollow shafts as described in claim 3, characterized in that, The forging hole (14) is a tapered hole, with the coarse end of the forging hole (14) close to the fine end of the mandrel (2).

5. The forging die for hollow shafts as described in claim 4, characterized in that, The taper of the forging hole (14) is b, where 1:10≤b≤1:

5.

6. The forging die for hollow shafts as described in any one of claims 1-5, characterized in that, The mold body (1) is also coaxially provided with an installation shaft (4) at one end, which is used to detachably connect with the flat forging machine body.

7. The forging die for hollow shafts as described in claim 6, characterized in that, A high-temperature resistant protective layer (3) is provided on the hole wall of the forging hole (14) and the outer circular surface of the mandrel (2).

8. The forging die for hollow shafts as described in claim 7, characterized in that, The high-temperature resistant protective layer (3) is made of forged graphite emulsion material.

9. A flat forging machine for hollow shafts, comprising a flat forging machine body (6), characterized in that, It also includes three hollow shaft forging dies arranged side by side as described in claim 1. The hollow shaft forging dies are horizontally and movably arranged on the flat forging machine body (6). The three hollow shaft forging dies are, in order, die one (8), die two (9) and die three (10). Die one (8) is used for pre-forging one end of the billet, die two (9) is used for final forging one end of the pre-forged billet, and die three (10) is used for final forging the other end of the billet. The length of the mandrel (2) of die one (8) is greater than the length of the mandrel (2) of die two (9), and the depth of the forging hole (14) of die one (8) is greater than the depth of the forging hole (14) of die two (9). The structures of die two (9) and die three (10) are the same, and the diameters of the mandrels (2) of die one (8), die two (9) and die three (10) are the same.

10. The flat forging machine for hollow shafts as described in claim 9, characterized in that, It also includes a push mold (11), which includes a push disk and a mounting shaft (4) arranged coaxially. The push mold (11) is horizontally and movably arranged on the flat forging machine body (6). The push mold (11) and the second mold (9) are symmetrically arranged on both sides of the third mold (10).

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