A hot extrusion die and method for forming stepped shaft forgings

Abstract

This invention provides a hot extrusion die and method for forming stepped shaft forgings, relating to the field of forging technology. The hot extrusion die for forming stepped shaft forgings includes an upper die mechanism, a first lower die mechanism, an extrusion cylinder, lower die inserts, and a base. The upper die mechanism includes an upper die column with an upper die cavity at its bottom for forming a journal. The first lower die mechanism has a through-hole lower die cavity for forming the shaft body. The bottom of the first lower die mechanism is supported on the base by a lower die seat. The extrusion cylinder is coaxially disposed on the top of the first lower die mechanism. Multiple lower die inserts are stacked vertically to form a second lower die mechanism with a second lower die cavity for forming another journal. The maximum vertical dimension of the lower die insert is less than or equal to the distance from the bottom of the first lower die mechanism to the base. This hot extrusion die not only enables the hot extrusion forming of large stepped shaft forgings but also has high production efficiency.

Description

Technical Field

[0001] This invention relates to the field of forging technology, and more specifically, to a hot extrusion die and method for forming stepped shaft forgings. Background Technology

[0002] Forging processes include many techniques, among which hot extrusion is a common one. This process is mainly used to manufacture long parts, bars, tubes, and profiles with ordinary cross-sections. These extruded parts can be used directly as structural components or cut and then precision-machined as machined forgings. Compared to manufacturing large forgings using vacuum smelting or electroslag remelting of steel ingots, forgings formed by hot extrusion have higher quality. Compared to manufacturing large forgings using traditional free forging methods, hot extrusion also offers higher production efficiency. Therefore, the manufacture of some large forgings is gradually adopting hot extrusion. However, hot extrusion forgings of shafts are generally made of bars of uniform diameter with simple shapes, making them unsuitable for forming large stepped shaft forgings. Summary of the Invention

[0003] The present invention aims to solve, to some extent, the problem that existing hot extrusion dies are difficult to apply to large stepped shaft forgings.

[0004] To address the aforementioned problems, this invention provides a hot extrusion die for forming stepped shaft forgings. The stepped shaft forging includes a shaft body and journals located at both ends of the shaft body. The die includes an upper die mechanism, a first lower die mechanism, an extrusion cylinder, a lower die insert, and a base. The upper die mechanism includes an upper die column with an upper die cavity at its bottom end. The first lower die mechanism has a through-hole lower die cavity, and its bottom is supported on the base by a lower die holder. The extrusion cylinder is coaxially disposed at the top of the first lower die mechanism, and its inner diameter is larger than that of the first lower die. The inner diameter of the cavity, the inner diameter of the extrusion cylinder is greater than or equal to the outer diameter of the upper die column, and a plurality of lower die inserts are used to stack vertically in sequence to form a second lower die mechanism with a second lower die cavity, and the outer diameter of the second lower die mechanism is equal to the inner diameter of the first lower die cavity, the top end of the second lower die mechanism is flush with the top end of the first lower die mechanism, the bottom end of the second lower die mechanism is supported on the base, the maximum vertical dimension of the lower die insert is less than or equal to the distance from the bottom end of the first lower die mechanism to the base, and the inner diameter of the second lower die cavity and the inner diameter of the upper die cavity are respectively smaller than the inner diameter of the first lower die cavity.

[0005] The hot extrusion die for forming stepped shaft forgings provided by this invention has, but is not limited to, the following technical advantages compared to the prior art:

[0006] Before hot extruding the initial billet into a stepped shaft forging, multiple lower die inserts can be stacked vertically to form a second lower die mechanism coaxial with the first lower die cavity. For example, multiple lower die inserts can be stacked from the top and / or bottom ports of the first lower die cavity to form a second lower die mechanism with a second lower die cavity. After the multiple lower die inserts form the second lower die mechanism, the top end of the second lower die mechanism is flush with the bottom end of the first lower die mechanism, the bottom end of the second lower die mechanism is supported on a base, and the outer diameter of the second lower die mechanism is equal to the inner diameter of the first lower die cavity. The inner diameter of the extrusion cylinder is larger than the inner diameter of the first lower die cavity, and the inner diameter of the extrusion cylinder is larger than or equal to the outer diameter of the upper die column. In this way, the initial billet can be placed in the extrusion cylinder, and then the upper die column can be lowered into the extrusion cylinder to extrude the initial billet, thereby forming the journal of the stepped shaft forging in the upper die cavity and the second lower die cavity, respectively. After the journal is formed, since the maximum vertical dimension of the lower die insert is less than or equal to the distance from the bottom of the first lower die mechanism to the base, it is only necessary to move multiple lower die inserts in the second lower die mechanism sequentially along a predetermined direction perpendicular to the vertical. As the lower die inserts that abut against the base are moved away, the adjacent upper lower die inserts will move out of the second lower die cavity under gravity and abut against the base, thus ensuring that there are no lower die inserts in the first lower die cavity. Then, the upper die column can continue to move downwards to extrude the initial blank. Since the inner diameters of the second lower die cavity and the upper die cavity are smaller than the inner diameter of the first lower die cavity, as the upper die column continues to move downwards, the shaft body of the stepped shaft forging gradually forms in the first lower die cavity. This hot extrusion die not only enables the hot extrusion forming of large stepped shaft forgings, but also, after the journal is formed, there is no need to reset the upper die column upwards, nor to move the extrusion cylinder and the first lower die mechanism; only the second lower die mechanism needs to be moved, resulting in high production efficiency.

[0007] Furthermore, the number of lower mold inserts is greater than or equal to three. Between two adjacent lower mold inserts in the vertical direction of the second lower mold mechanism, the bottom side surface of the upper lower mold insert includes a bottom plane and a bottom inclined surface connected in sequence along a set direction, and the end of the bottom inclined surface away from the bottom plane is higher than the bottom plane. The top side surface of the lower mold insert includes a second top inclined surface, a top plane and a first top inclined surface connected in sequence along the set direction, the end of the first top inclined surface away from the top plane is higher than the top plane, and the end of the second top inclined surface away from the top plane is lower than the top plane.

[0008] Wherein, the set direction is perpendicular to the vertical direction, and the first top inclined surface, the second top inclined surface, and the bottom inclined surface are all parallel to each other.

[0009] Furthermore, the projected area of ​​the bottom plane on the base is greater than the projected area of ​​the bottom inclined surface on the base, the intersection line between the bottom inclined surface and the bottom plane is the bottom intersection line, the intersection line between the top plane and the first top inclined surface is the top intersection line, and the top intersection line and the bottom intersection line are on the same vertical plane.

[0010] Furthermore, the lower mold base has an arc-shaped concave surface on the side facing the axis of the first lower mold mechanism, and the arc-shaped concave surface matches the peripheral surface of the lower mold insert.

[0011] Furthermore, along the top-to-bottom direction of the second lower mold mechanism, at least a portion of the lower mold inserts are provided with insert holes, and a plurality of insert holes are used to combine to form the second lower mold cavity.

[0012] Furthermore, the hot extrusion die for forming the stepped shaft forging also includes a guide groove, which is disposed on the base and extends along the set direction, and the lower die insert is used to move along the guide groove.

[0013] Furthermore, the hot extrusion die for forming the stepped shaft forging also includes a driving mechanism, which is disposed on the base and is used to drive the lower die insert to move along the guide groove.

[0014] Furthermore, the driving mechanism includes a motor, a lead screw, a support, and a threaded component. Multiple supports are sequentially arranged on the base along the set direction. The lead screw is rotatably connected to the support, and one end of the lead screw is connected to the motor. The threaded component is threadedly connected to the lead screw. The threaded component is used to connect to the lower mold insert at the end of the multiple lower mold inserts.

[0015] Furthermore, the upper mold mechanism also includes an upper mold base and an upper mold connecting frame arranged sequentially from top to bottom. The upper mold column is fixed to the lower side of the upper mold base through the upper mold connecting frame. The upper mold base is used to connect with the pressure device.

[0016] The present invention also provides a hot extrusion method for forming stepped shaft forgings, based on the hot extrusion die for forming stepped shaft forgings as described above, comprising:

[0017] Multiple lower mold inserts are stacked vertically to form a second lower mold mechanism with a second lower mold cavity, and the second lower mold mechanism is located in the first lower mold cavity;

[0018] The initial blank is placed in the extrusion cylinder and supported at the top of the first lower die mechanism and the second lower die mechanism;

[0019] The upper die column is lowered into the extrusion cylinder so that the initial blank forms journals in the upper die cavity and the second lower die cavity, respectively.

[0020] The lower mold inserts that abut against the base are gradually moved away from the lower mold base in a set direction until all the lower mold inserts are moved out of the second lower mold cavity;

[0021] The upper mold column continues to move downward so that the initial blank forms a shaft in the first lower mold cavity.

[0022] Since the hot extrusion method for forming stepped shaft forgings is based on the hot extrusion die for forming stepped shaft forgings, the technical effect of the hot extrusion method for forming stepped shaft forgings is at least the same as the technical effect of the hot extrusion die for forming stepped shaft forgings, and the technical effect of the hot extrusion method for forming stepped shaft forgings will not be described further. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of the hot extrusion die before hot extrusion of the initial blank, according to a specific embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the upper mold mechanism and the first lower mold mechanism after forming a journal on the initial blank, according to a specific embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of the stepped shaft forging finally formed according to a specific embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the horizontal cross-section of the lower mold base according to a specific embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the main structure of the lower mold insert according to a specific embodiment of the present invention;

[0028] Figure 6 A bottom view of the lower mold insert without insert holes, according to a specific embodiment of the present invention;

[0029] Figure 7 A bottom view of a lower mold insert with insert holes, as shown in a specific embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram illustrating the removal of the second lower mold mechanism from the first lower mold mechanism according to a specific embodiment of the present invention.

[0031] Figure 9 This is a flowchart of a hot extrusion method for forming stepped shaft forgings according to a specific embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Stepped shaft forging; 11. First journal; 12. Second journal; 13. Shaft body; 2. Extrusion cylinder; 3. Upper die mechanism; 31. Upper die column; 311. Upper die cavity; 32. Upper die connecting frame; 33. Upper die base; 4. First lower die mechanism; 41. First lower die cavity; 42. Lower die base; 421. Arc-shaped concave surface; 5. Second lower die mechanism; 51. Lower die insert; 511. Insert hole; 512. First top inclined surface; 513. Top plane; 514. Second top inclined surface; 515. Bottom plane; 516. Bottom inclined surface; 52. Second lower die cavity; 6. Initial blank; 7. Base; 8. Guide groove; 91. Lead screw; 92. Threaded part; 93. Support. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Furthermore, in the attached figures, the Z-axis represents the vertical direction, that is, the up-down position, with the positive direction of the Z-axis indicating up and the negative direction indicating down; the Y-axis represents the horizontal direction, that is, the left-right position, with the positive direction of the Y-axis indicating left and the negative direction indicating right; the X-axis represents the vertical direction, that is, the front-back position, with the positive direction of the X-axis indicating front and the negative direction indicating back. It should also be noted that the aforementioned representations of the Z, Y, and X axes are merely for the convenience of describing the present invention and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0037] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0038] See Figure 1-3 and Figure 8This embodiment provides a hot extrusion die for forming stepped shaft forgings, used to forge stepped shaft forgings 1. The stepped shaft forging 1 includes a shaft body 13 and journals located at both ends of the shaft body 13. It includes an upper die mechanism 3, a first lower die mechanism 4, an extrusion cylinder 2, a lower die insert 51, and a base 7. The upper die mechanism 3 includes an upper die column 31, with an upper die cavity 311 at its bottom end. The first lower die mechanism 4 has a through-hole first lower die cavity 41, and its bottom is supported on the base 7 by a lower die seat 42. The extrusion cylinder 2 is coaxially disposed on the top of the first lower die mechanism 4, and the inner diameter of the extrusion cylinder 2 is larger than that of the first lower die cavity. The inner diameter of the extrusion cylinder 2 is greater than or equal to the outer diameter of the upper die column 31. Multiple lower die inserts 51 are used to stack vertically to form a second lower die mechanism 5 with a second lower die cavity 52. ​​The outer diameter of the second lower die mechanism 5 is equal to the inner diameter of the first lower die cavity 41. The top end of the second lower die mechanism 5 is flush with the top end of the first lower die mechanism 4. The bottom end of the second lower die mechanism 5 is supported on the base 7. The maximum vertical dimension of the lower die insert 51 is less than or equal to the distance from the bottom end of the first lower die mechanism 4 to the base 7. The inner diameter of the second lower die cavity 52 and the inner diameter of the upper die cavity 311 are respectively smaller than the inner diameter of the first lower die cavity 41.

[0039] In this embodiment, before hot extruding the initial blank 6 to form a stepped shaft forging 1, multiple lower die inserts 51 can be stacked vertically to form a second lower die mechanism 5 coaxial with the first lower die cavity 41. For example, multiple lower die inserts 51 can be stacked from the top port and / or bottom port of the first lower die cavity 41 to form a second lower die mechanism 5 with a second lower die cavity 52. ​​After the multiple lower die inserts 51 form the second lower die mechanism 5, the top end of the second lower die mechanism 5 is flush with the bottom end of the first lower die mechanism 4, the bottom end of the second lower die mechanism 5 is supported on the base 7, and the outer diameter of the second lower die mechanism 5 is equal to the inner diameter of the first lower die cavity 41. The inner diameter of the extrusion cylinder 2 is greater than the inner diameter of the first lower die cavity 41, and the inner diameter of the extrusion cylinder 2 is greater than or equal to the outer diameter of the upper die column 31. Thus, the initial blank 6 can be placed into the extrusion cylinder 2, and then the upper die column 31 can be lowered into the extrusion cylinder 2 to extrude the initial blank 6, thereby forming the journal of the stepped shaft forging 1 in the upper die cavity 311 and the second lower die cavity 52 respectively (e.g., Figure 2 (As shown).

[0040] After the journal is formed, since the maximum vertical dimension of the lower die insert 51 is less than or equal to the distance from the bottom of the first lower die mechanism 4 to the base 7, it is only necessary to move multiple lower die inserts 51 in the second lower die mechanism 5 sequentially along a set direction perpendicular to the vertical. As the lower die insert 51 that abuts against the base 7 is moved away, the adjacent upper lower die insert 51 will move out of the second lower die cavity 52 under gravity and abut against the base 7, thereby ensuring that there are no lower die inserts 51 in the first lower die cavity 41. Then, the upper die column 31 can continue to move down to compress the initial blank 6. Since the inner diameter of the second lower die cavity 52 and the inner diameter of the upper die cavity 311 are smaller than the inner diameter of the first lower die cavity 41, as the upper die column 31 continues to move down, the shaft body 13 of the stepped shaft forging 1 is gradually formed in the first lower die cavity 41 (e.g., Figure 3 (As shown).

[0041] This hot extrusion die can not only realize the hot extrusion forming of large stepped shaft forgings 1, but also, after the journal is formed, there is no need to reset the upper die column 31 upwards, nor is there a need to move the extrusion cylinder 2 and the first lower die mechanism 4. Only the second lower die mechanism 5 needs to be moved away, which has high production efficiency.

[0042] Here, "removing the second lower mold mechanism 5" means that there are no lower mold inserts 51 in the first lower mold cavity 41. For example... Figure 1 As shown, for example, the second lower mold mechanism 5 is composed of seven vertically stacked lower mold inserts 51. From top to bottom, these seven lower mold inserts 51 are designated as the first insert, the second insert, the third insert, the fourth insert, the fifth insert, the sixth insert, and the seventh insert. When the second lower mold mechanism 5 needs to be removed, the seventh insert is first moved along a set direction, for example, to the right. As the seventh insert is moved, the sixth insert replaces the original position of the seventh insert under gravity, that is, the sixth insert abuts against the base 7. Then the sixth insert is moved again. After that, the fifth insert, the fourth insert, the third insert, the second insert, and the first insert are moved in sequence.

[0043] Wherein, the maximum vertical dimension of the lower mold insert 51 is less than or equal to the distance from the bottom end of the first lower mold mechanism 4 to the base 7, meaning that the maximum vertical dimension of any lower mold insert 51 is less than or equal to the distance from the bottom end of the first lower mold mechanism 4 to the base 7.

[0044] Optionally, see Figure 1 , Figure 5 and Figure 8The number of lower mold inserts 51 is greater than or equal to three. Between two adjacent lower mold inserts 51 in the vertical direction of the second lower mold mechanism 5, the bottom side of the upper lower mold insert 51 includes a bottom plane 515 and a bottom inclined surface 516 connected in sequence along a set direction, and the end of the bottom inclined surface 516 away from the bottom plane 515 is higher than the bottom plane 515. The top side of the lower mold insert 51 includes a second top inclined surface 514, a top plane 513 and a first top inclined surface 512 connected in sequence along the set direction, the end of the first top inclined surface 512 away from the top plane 513 is higher than the top plane 513, and the end of the second top inclined surface 514 away from the top plane 513 is lower than the top plane 513.

[0045] The set direction is perpendicular to the vertical direction, and the first top inclined surface 512, the second top inclined surface 514, and the bottom inclined surface 516 are all parallel to each other.

[0046] In this embodiment, as Figure 1 As shown, for example, the second lower mold mechanism 5 is composed of 7 vertically stacked lower mold inserts 51, which are named as the first insert, second insert, third insert, fourth insert, fifth insert, sixth insert and seventh insert from top to bottom. The principle of the second lower mold mechanism 5 from the use state to the removal state is as follows: First, the seventh insert is moved along the set direction. For example, the seventh insert is moved to the right. When the second top inclined surface 514 of the seventh insert moves to the right and matches the bottom inclined surface 516 of the sixth insert, the sixth insert will gradually descend as the seventh insert moves to the right until the bottom plane 515 of the sixth insert abuts against the base 7. Similarly, after the sixth insert abuts against the base 7, the fifth insert also gradually descends until it abuts against the base 7 as the sixth insert moves to the right. And so on. Except for the seventh insert, all other inserts gradually descend until they abut against the base 7, ensuring the stability of the lower mold insert 51 when it moves, and preventing it from suddenly hitting the base 7, avoiding the generation of abnormal noises from impact, so as to ensure that the base 7 and the lower mold insert 51 are not damaged.

[0047] See Figure 1 , Figure 6-8 Along the second lower mold mechanism 5 from top to bottom, at least a portion of the lower mold insert 51 is provided with insert holes 511, and a plurality of insert holes 511 are used to form the second lower mold cavity 52.

[0048] Optionally, some of the lower mold inserts 51 may have insert holes 511, for example... Figure 1As shown, the first, second, and third inserts have insert holes 511. The insert holes 511 on the first and second inserts are through holes, while the insert hole 511 on the third insert can be a blind hole. Thus, when multiple lower mold inserts 51 are stacked to form the second lower mold mechanism 5, the insert holes 511 on the first, second, and third inserts form the second lower mold cavity 52, wherein the depth of the second lower mold cavity 52 is greater than or equal to... Figure 2 The length of the second journal 12.

[0049] The upper journal is the first journal 11, which is formed in the upper mold cavity 311, and the lower journal is the second journal 12, which is formed in the second lower mold cavity 52.

[0050] See Figure 6 and Figure 7 The projected area of ​​the bottom plane 515 on the base 7 is greater than the projected area of ​​the bottom inclined surface 516 on the base 7. The intersection line between the bottom inclined surface 516 and the bottom plane 515 is the bottom intersection line. The intersection line between the top plane 513 and the first top inclined surface 512 is the top intersection line. The top intersection line and the bottom intersection line are on the same vertical plane.

[0051] In this embodiment, the projected area of ​​the bottom plane 515 on the base 7 is greater than the projected area of ​​the bottom inclined surface 516 on the base 7. The intersection line between the bottom inclined surface 516 and the bottom plane 515 is the bottom intersection line, and the intersection line between the top plane 513 and the first top inclined surface 512 is the top intersection line. The top intersection line and the bottom intersection line are on the same vertical plane. Thus, the center of gravity of the lower mold insert 51 is located directly above the bottom plane 515, ensuring that the lower mold insert 51 will not tip over due to the presence of the bottom inclined surface 516. In other words, it ensures that the lower mold insert 51 is always supported on the base 7 by the bottom plane 515, which facilitates the cooperation between the second top inclined surface 514 and the bottom inclined surface 516.

[0052] See Figure 1 and Figure 4 Optionally, the lower mold base 42 is provided with an arc-shaped concave surface 421 on one side facing the axis of the first lower mold mechanism 4, and the arc-shaped concave surface 421 matches the peripheral surface of the lower mold insert 51.

[0053] In this embodiment, one side of the lower mold base 42 is an arc-shaped concave surface 421, which matches the peripheral side surface of the lower mold insert 51, ensuring horizontal support and limiting the lower mold insert 51, which is in contact with the base 7, so that the lower mold insert 51 can only move to the right.

[0054] See Figure 1Optionally, the hot extrusion die for forming the stepped shaft forging further includes a guide groove 8, which is disposed on the base 7 and extends along the set direction. The lower die insert 51 is used to move along the guide groove 8.

[0055] In this embodiment, the lower mold insert 51 that abuts against the base 7 can move laterally in the guide groove 8, and under the limitation of the arc concave surface 421 of the lower mold base 42, the lower mold insert 51 that abuts against the base 7 is limited to moving only to the right in a straight line.

[0056] like Figure 1 As shown, for example, the second lower mold mechanism 5 is composed of seven vertically stacked lower mold inserts 51. From top to bottom, these seven lower mold inserts 51 are designated as the first insert, second insert, third insert, fourth insert, fifth insert, sixth insert, and seventh insert. The principle of the second lower mold mechanism 5 from its working state to its removed state is as follows: First, the seventh insert is moved to the right. When the second top inclined surface 514 of the seventh insert moves to the right and mates with the bottom inclined surface 516 of the sixth insert, the sixth insert will gradually descend along the arc-shaped concave surface 421 as the seventh insert moves to the right, until the bottom plane 515 of the sixth insert abuts against the base 7. Similarly, after the sixth insert abuts against the base 7, as the sixth insert moves to the right, the fifth insert also gradually descends until it abuts against the base 7, and so on. Except for the seventh insert, all other inserts gradually descend until they abut against the base 7 (e.g., ...). Figure 8 (As shown).

[0057] When it is necessary to form the next stepped shaft forging 1, the upper die post 31 can be moved upward to reset it, and then the previously formed stepped shaft forging 1 can be taken out upward. Afterwards, as... Figure 8 As shown, the seventh insert is moved to the left so that the first insert abuts against the arc-shaped concave surface 421 of the lower mold base 42. Then, the seventh insert continues to move to the left. With the first insert limited by the arc-shaped concave surface 421 and the cooperation of the second top inclined surface 514 of the sixth insert and the bottom inclined surface of the seventh insert, the seventh insert will move upwards along the arc-shaped concave surface 421 and gradually enter the first lower mold cavity 41. As the seventh insert continues to move to the left, it will eventually form as shown... Figure 1 The second lower die mechanism 5 is shown. The use and removal of the second lower die mechanism 5 do not require the removal of the first lower die mechanism 4 and the extrusion cylinder 2, which facilitates the efficient mass production of stepped shaft forgings 1.

[0058] See Figure 1 Optionally, the hot extrusion die for forming the stepped shaft forging further includes a driving mechanism, which is disposed on the base 7 and is used to drive the lower die insert 51 to move along the guide groove 8.

[0059] In this embodiment, a drive mechanism is also provided on the base 7, which can drive the lateral movement of the seventh insert, thus freeing up manpower.

[0060] See Figure 1 Optionally, the drive mechanism includes a motor (not shown in the figure), a lead screw 91, a support 93, and a threaded component 92. The plurality of supports 93 are sequentially arranged on the base 7 along the set direction. The lead screw 91 is rotatably connected to the support 93, and one end of the lead screw 91 is connected to the motor. The threaded component 92 is threadedly connected to the lead screw 91. The threaded component is used to connect with the lower mold insert 51 at the middle end of the plurality of lower mold inserts 51.

[0061] In this embodiment, the motor can drive the lead screw 91 to rotate, the threaded part 92 is connected to the seventh insert, and the lower die insert 51 is limited by the guide groove 8. The rotation of the lead screw 91 will drive the threaded part 92 to move laterally, so as to drive the seventh insert to move to the left or right.

[0062] See Figure 1 and Figure 8 Optionally, the upper mold mechanism 3 further includes an upper mold base 33 and an upper mold connecting frame 32 arranged sequentially from top to bottom. The upper mold column 31 is fixed to the lower side of the upper mold base 33 through the upper mold connecting frame 32. The upper mold base 33 is used to connect with the pressure device.

[0063] In this embodiment, the upper die column 31 is a component of the upper die mechanism 3 that can be inserted into the extrusion cylinder 2. The axial movement of the upper die column 31 within the extrusion cylinder 2 extrudes the initial blank 6 located inside the extrusion cylinder 2, thereby cooperating with the second lower die cavity 52 of the second lower die mechanism 5 to complete the extrusion forming of the first journal 11 and the second journal 12, and subsequently cooperating with the first lower die cavity 41 of the first lower die mechanism 4 to complete the extrusion forming of the shaft body 13. Therefore, the length of the upper die column 31 is preferably not less than the length of the extrusion cylinder 2, so that the upper die column 31 can penetrate deep into the bottom end of the extrusion cylinder 2 during the extrusion process. Of course, the length of the upper die column 31 can also be less than the length of the extrusion cylinder 2. When the length of the upper die column 31 is less than the length of the extrusion cylinder 2, an extension die column can be added between the upper die column 31 and the upper die connecting frame 32 if necessary. This extension die column can penetrate deep into the extrusion cylinder 2. The upper die base 33 can be connected to a pressure device to provide power for the upward and downward movement of the upper die mechanism 3, wherein the pressure device can be a conventional press.

[0064] See Figure 9 Another embodiment of the present invention provides a hot extrusion method for forming stepped shaft forgings, based on the hot extrusion die for forming stepped shaft forgings as described above, comprising:

[0065] Multiple lower mold inserts 51 are stacked vertically to form a second lower mold mechanism 5 with a second lower mold cavity 52, and the second lower mold mechanism 5 is located in the first lower mold cavity 41;

[0066] The initial blank 6 is placed in the extrusion cylinder 2 and supported on the top of the first lower die mechanism 4 and the second lower die mechanism 5;

[0067] The upper die column 31 is lowered into the extrusion cylinder 2 so that the initial blank 6 forms journals in the upper die cavity 311 and the second lower die cavity 52 respectively;

[0068] The lower mold inserts 51 that abut against the base 7 are gradually moved away from the lower mold base 42 in a set direction until all the lower mold inserts 51 are moved out of the second lower mold cavity 52.

[0069] The upper mold column 31 is moved further down so that the initial blank 6 forms a shaft 13 in the first lower mold cavity 41.

[0070] Since the hot extrusion method for forming stepped shaft forgings is based on the hot extrusion die for forming stepped shaft forgings, the technical effect of the hot extrusion method for forming stepped shaft forgings is at least the same as the technical effect of the hot extrusion die for forming stepped shaft forgings, and the technical effect of the hot extrusion method for forming stepped shaft forgings will not be described further.

[0071] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A hot extrusion die for forming stepped shaft forgings, used for forging stepped shaft forgings (1), the stepped shaft forging (1) comprising a shaft body (13) and journals located at both ends of the shaft body (13), characterized in that, The assembly includes an upper die mechanism (3), a first lower die mechanism (4), an extrusion cylinder (2), a lower die insert (51), and a base (7). The upper die mechanism (3) includes an upper die column (31), with an upper die cavity (311) at the bottom end of the upper die column (31). The first lower die mechanism (4) has a through-hole first lower die cavity (41), and the bottom of the first lower die mechanism (4) is supported on the base (7) by a lower die seat (42). The extrusion cylinder (2) is coaxially disposed on the top of the first lower die mechanism (4), and the inner diameter of the extrusion cylinder (2) is larger than the inner diameter of the first lower die cavity (41). The inner diameter of the extrusion cylinder (2) is greater than or equal to the outer diameter of the upper die column (31). The lower mold inserts (51) are stacked vertically to form a second lower mold mechanism (5) with a second lower mold cavity (52). The outer diameter of the second lower mold mechanism (5) is equal to the inner diameter of the first lower mold cavity (41). The top of the second lower mold mechanism (5) is flush with the top of the first lower mold mechanism (4). The bottom of the second lower mold mechanism (5) is supported on the base (7). The maximum vertical dimension of the lower mold insert (51) is less than or equal to the distance from the bottom of the first lower mold mechanism (4) to the base (7). The inner diameter of the second lower mold cavity (52) and the inner diameter of the upper mold cavity (311) are respectively less than the inner diameter of the first lower mold cavity (41).

2. The hot extrusion die for forming stepped shaft forgings according to claim 1, characterized in that, The number of the lower mold inserts (51) is greater than or equal to three. Between two adjacent lower mold inserts (51) in the vertical direction of the second lower mold mechanism (5), the bottom side of the upper lower mold insert (51) includes a bottom plane (515) and a bottom inclined surface (516) connected in sequence along a set direction, and the end of the bottom inclined surface (516) away from the bottom plane (515) is higher than the bottom plane (515). The top side of the lower mold insert (51) includes a second top inclined surface (514), a top plane (513) and a first top inclined surface (512) connected in sequence along the set direction, and the end of the first top inclined surface (512) away from the top plane (513) is higher than the top plane (513). The end of the second top inclined surface (514) away from the top plane (513) is lower than the top plane (513). The set direction is perpendicular to the vertical direction, and the first top inclined surface (512), the second top inclined surface (514), and the bottom inclined surface (516) are all parallel to each other.

3. The hot extrusion die for forming stepped shaft forgings according to claim 2, characterized in that, The projected area of ​​the bottom plane (515) on the base (7) is greater than the projected area of ​​the bottom inclined surface (516) on the base (7). The intersection line between the bottom inclined surface (516) and the bottom plane (515) is the bottom intersection line. The intersection line between the top plane (513) and the first top inclined surface (512) is the top intersection line. The top intersection line and the bottom intersection line are on the same vertical plane.

4. The hot extrusion die for forming stepped shaft forgings according to claim 2, characterized in that, The lower mold base (42) has an arc-shaped concave surface (421) on one side facing the axis of the first lower mold mechanism (4), and the arc-shaped concave surface (421) matches the peripheral surface of the lower mold insert (51).

5. The hot extrusion die for forming stepped shaft forgings according to claim 2, characterized in that, Along the second lower mold mechanism (5) from top to bottom, at least part of the lower mold insert (51) has insert holes (511), and a plurality of insert holes (511) are used to form the second lower mold cavity (52).

6. The hot extrusion die for forming stepped shaft forgings according to claim 2, characterized in that, It also includes a guide groove (8), which is disposed on the base (7) and extends along the set direction. The lower mold insert (51) is used to move along the guide groove (8).

7. The hot extrusion die for forming stepped shaft forgings according to claim 6, characterized in that, It also includes a drive mechanism, which is disposed on the base (7) and is used to drive the lower mold insert (51) to move along the guide groove (8).

8. The hot extrusion die for forming stepped shaft forgings according to claim 7, characterized in that, The drive mechanism includes a motor, a lead screw (91), a support (93), and a threaded component (92). Multiple supports (93) are sequentially arranged on the base (7) along the set direction. The lead screw (91) is rotatably connected to the support (93), and one end of the lead screw (91) is connected to the motor. The threaded component (92) is threadedly connected to the lead screw (91). The threaded component (92) is used to connect with the lower mold insert (51) located at the end of the multiple lower mold inserts (51).

9. The hot extrusion die for forming stepped shaft forgings according to claim 1, characterized in that, The upper mold mechanism (3) also includes an upper mold base (33) and an upper mold connecting frame (32) arranged sequentially from top to bottom. The upper mold column (31) is fixed to the lower side of the upper mold base (33) through the upper mold connecting frame (32). The upper mold base (33) is used to connect with the pressure device.

10. A hot extrusion method for forming stepped shaft forgings, based on the hot extrusion die for forming stepped shaft forgings as described in any one of claims 1-9, characterized in that, include: Multiple lower mold inserts (51) are stacked vertically to form a second lower mold mechanism (5) with a second lower mold cavity (52), and the second lower mold mechanism (5) is located in the first lower mold cavity (41); The initial blank (6) is placed in the extrusion cylinder (2) and supported at the top of the first lower die mechanism (4) and the second lower die mechanism (5); The upper die column (31) is lowered into the extrusion cylinder (2) so that the initial blank (6) forms journals in the upper die cavity (311) and the second lower die cavity (52) respectively; The lower mold inserts (51) that abut against the base (7) are gradually moved away from the lower mold base (42) in a set direction until all the lower mold inserts (51) are moved out of the second lower mold cavity (52); The upper mold column (31) is moved further down so that the initial blank (6) forms a shaft (13) in the first lower mold cavity (41).

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