A clamping process and die suitable for an automatic line swaging press for a four-balance-block crankshaft

Abstract

The present application relates to a kind of automatic line swaging press clamping processes and mould suitable for four balance block crankshafts, and the automatic line swaging press clamping process suitable for four balance block crankshafts, comprising the following steps: blank is placed in clamping lower die by automatic line step beam tong finger clamping after heating;Swaging press slider drops;Clamping upper die is contacted with blank under the driving of slider;Clamping forming;Slider rises;Clamping upper die returns to upper dead point;Ejection system lifts clamping work step piece;Automatic line step beam tong finger clamps away clamping work step piece.The mould includes upper die and lower die, and the upper die includes upper seat, clamping upper die and positioning key;The lower die includes lower seat, clamping lower die, lower ejector rod holder, ejector rod holder pressure block and ejection mechanism.The present application reduces the local cross-sectional area of blank, increases overall length, optimizes the volume distribution of blank, achieves the effect of blank making close to roll forging process, and improves material utilization rate;Research finds that the material utilization rate of four balance block crankshaft is improved from 70% in prior art to more than 75%.

Description

Technical Field

[0001] This invention belongs to the field of forging technology, specifically relating to an automatic line forging press pressing process and mold suitable for four-balance block crankshafts of passenger vehicles. Background Technology

[0002] Currently, automated forging lines for passenger vehicle crankshafts both domestically and internationally do not feature roll forging machines; they typically employ a two-step process: pre-forging and final forging. This lack of a billet preparation step prevents the proper allocation of billet volume, necessitating the selection of larger blank sizes. This restricts the production of passenger vehicle crankshafts, especially four-balance-block crankshafts. Figure 1 As shown, the material utilization rate has been improved.

[0003] Under current technology, the material utilization rate of four-balance-block crankshafts is only about 70%, resulting in high manufacturing costs and seriously affecting the product's market competitiveness and profitability.

[0004] The existing forging process for a four-balance-block crankshaft is as follows: heating → pre-forging → final forging, such as... Figure 2 As shown. Because there are no balance blocks at the J2 and J4 positions of the main journal, less material is needed for forming. During die forging, excess metal is discharged outside the mold cavity, causing excessively large local flash size, resulting in low material utilization. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic line forging press clamping process for a four-balance block crankshaft of a passenger vehicle, and to provide a clamping die for the automatic line forging press clamping process for a four-balance block crankshaft of a passenger vehicle, so as to solve the problem of clamping and pressing a passenger vehicle crankshaft blank on a forging press.

[0006] The objective of this invention is achieved through the following technical solution: An automatic linear forging press clamping process for a four-balance-block crankshaft includes the following steps: A. After the billet is heated, it is held by the automatic line's stepping beam clamps and placed in the pressing mold 6; B. The forging press slide descends; C. The upper die 2 contacts the blank under the action of the slider; D. Press forming; E. The slider rises; F. Press the upper mold 2 back to the top dead center; G. Ejection system lifting and clamping step components; H. Automatic line step beam clamp finger clamping pressing step component.

[0007] A die for the clamping process of an automatic line forging press for a four-balance-block crankshaft includes an upper die and a lower die. The upper die includes an upper seat 1, a clamping upper die 2, and a positioning key 3. The lower die includes a lower seat 5, a clamping lower die 6, a lower ejector rod support 7, an ejector rod support block 8, and an ejection mechanism 9. The upper clamping die 2 is fastened to the upper seat 1. The upper clamping die 2 and the upper seat 1 are positioned in the front-back direction by the positioning key 3, and in the left-right direction by the extrusion positioning surface I1-2 of the upper seat 1. The lower clamping die 6 is fastened to the lower seat 5. The keyway is designed on the lower clamping die 6. The lower clamping die 6 and the lower seat 5 are positioned in the front-back direction by the lower seat front-back positioning key 5-2, and in the left-right direction by the extrusion positioning surface II5-3 of the lower seat 5. The ejection mechanism 9, the ejector rod support 7, and the ejector rod support block 8 form a clamping step ejection system.

[0008] Furthermore, the upper clamping mold 2 is fastened to the upper seat 1 by screw I4, and the lower clamping mold 6 is fastened to the lower seat 5 by screw III11.

[0009] Furthermore, the stroke of the lower push rod support 7 is limited within the bottom groove of the lower seat 5 by the push rod support pressure block 8 and the screw II 10.

[0010] Furthermore, the ejection mechanism 9 consists of a lower ejector rod a, a lower ejector rod spring b, a spring guide post c, an ejector rod pressure block d, and a screw e. The spring guide post c is limited by the limiting groove on the lower ejector rod a and the ejector rod pressure block d. The spring guide post c is installed in the limiting groove of the lower ejector rod a. The lower ejector rod spring b is sleeved on the spring guide post c. The ejector rod pressure block d is fixed to the lower ejector rod a by the screw e.

[0011] Furthermore, the cavity of the clamping lower mold 6 is divided into a cavity that participates in forming and a cavity that does not participate in forming. The cavity that does not participate in forming adopts a design of circular cross section + inclined surface + large fillet. The diameter (2R) of the circular cross section of the cavity is equal to the diameter of the blank D + 5~10mm. The angle of the inclined surface 19 is between 15° and 20°. The value of the large fillet R120 is generally 15-25mm. The mold closing height H is equal to the diameter of the blank D + 20~30mm. The clamping lower mold 6 has slots at both ends. The cavity that participates in forming adopts a design of clamping boss 6-4 and inclined surface 19. The angle of the inclined surface in this area is 1°-3° smaller than the angle of the inclined surface in the cavity that does not participate in forming. The fillet R221 at the root of the clamping boss 6-4 is 20~25mm.

[0012] Furthermore, the clamping boss corresponds to the main journal position of the four balance block crankshaft J2 / J4. The mold closing height H1 / H2 is determined by the material volume required for the final forging of the main journal area of ​​the four balance block crankshaft J2 / J4. The diameter D1 of the thrust surface near the main journal J4 is greater than the diameter D2 of the main journal, so H1 = D1 + 1~2mm is sufficient. The mold closing height H2 at the position of the main journal J2 is D2 + 6~10mm.

[0013] Furthermore, the height Y of the clamping die 6 is the same as the height of the pre-forging die. The height A1 / C1 of the clamping boss of the clamping die 6 is determined by the amount of blank deformation, i.e., blank diameter D - closing die height H1 / H2. At section C, the height C1 of the clamping boss of the clamping die 6 is greater than the amount of blank deformation (blank diameter D - closing die height H1) / 2. At section A, the height A1 of the clamping boss of the clamping die 6 is greater than the amount of blank deformation (blank diameter D - clamping die height H2) / 2. The drop A1-C1 of the clamping boss 6-4 of the clamping die 6 is controlled between 0 and 10 mm. The minimum wall thickness Y1 of the clamping die 6 is between 25 and 30 mm.

[0014] Furthermore, the thickness T1 / T2 of the clamping boss 6-4 of the clamping die 6 is determined by the axial length L1 / L2 of the main journal region of the four balance block crankshaft J2 / J4 and the material volume required for final forging. The thickness T1 of the clamping boss 6-4 of the clamping die 6 is equal to the axial length L1-1 to 3 mm of the J2 main journal, and the thickness T2 of the clamping boss 6-4 is equal to the axial length L2-1 to 3 mm of the J4 main journal. To ensure the strength of the clamping boss, a draft angle of 40° to 45° is designed in the thickness direction of the clamping boss 6-4.

[0015] Furthermore, the upper clamping die 2 adopts a structure of a plane + clamping boss. The fillet radius of the clamping boss is generally between 15 and 25 mm. The minimum wall thickness Z1 of the upper clamping die 2 is between 50 and 60 mm. The length A of the increased blank is determined by the deformation of the blank (the diameter of the blank D - the closing height H1 / H2). The length of the increased blank is between 10 mm and 20 mm.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention is applicable to the automatic line forging press pressing process of four-balance block crankshafts for passenger vehicles. By pressing, the local cross-sectional area of ​​the billet is reduced, the overall length is increased, and the volume distribution of the billet is optimized, achieving a billet-making effect close to that of roll forging and improving material utilization. Research has found that the material utilization rate of four-balance block crankshafts has been increased from 70% in the prior art to over 75%. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 Schematic diagram of the four balanced crankshafts in this invention; Figure 2 The present invention utilizes the existing forging process flow; Figure 3 Forging process flow in this invention; Figure 4 Assembly structure diagram of the clamping mold in this invention; Figure 5 Schematic diagram of the clamping mold structure in this invention; Figure 6 A partially enlarged view of the ejection mechanism in its non-operational state in this invention; Figure 7 A schematic diagram of the clamping mold in the lifted state in this invention; Figure 8 Enlarged view of a portion of the lifted state in this invention; Figure 9 Schematic diagram of the lower seat structure in this invention; Figure 10 Schematic diagram of the pressing die structure in this invention; Figure 11 Schematic diagram of the upper seat structure in this invention; Figure 12 Schematic diagram of the pressing upper mold structure in this invention; Figure 13 A partial enlarged view of the ejection mechanism in this invention; Figure 14 In this invention, a pressing die is used; Figure 15 In this invention, the upper mold is pressed; Figure 16 Schematic diagram of the clamping mold in this invention; Figure 17 Side view of section A in this invention; Figure 18 Side view of section B in this invention; Figure 19 Side view of section C in this invention; Figure 20 A simplified diagram illustrating the principle of the clamping mold in this invention.

[0019] In the diagram: 1. Upper seat 1-1. Upper seat front and rear positioning keyway 1-2. Extrusion positioning surface I 2. Pressing upper die 2-1. Pressing upper die keyway 2-2. Pressing upper die extrusion positioning surface 3. Positioning key 4. Screw I 5. Lower seat 5-1. Ejector hole I 5-2. Lower seat front and rear positioning key 5-3. Extrusion positioning surface II 6. Pressing lower die 6-1. Ejector hole II 6-2. Pressing lower die keyway 6-3. Pressing lower die extrusion positioning surface 6-4. Pressing boss 6-5. Pliers finger slot 7. Lower ejector rod support 8. Ejector rod support pressure block 9. Ejection mechanism 9-1. Spring guide post C limiting groove 10. Screw II 11. Screw III 12. W1 balance block 13. W4 balance block 14. W5 balance block 15. W8 balance block 16. Section A 17. Section B 18. Section C 19. Inclined surface 20. Large fillet R1 21. Root fillet R2 22. Circular section 2R a. Lower push rod b. Lower push rod spring c. Spring guide post d. Push rod pressure block e. Screw F. Push rod hole end face. Detailed Implementation

[0020] The present invention will be further described below with reference to embodiments: The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] The forging process of this invention is as follows: Figure 3 As shown, the process includes: 1. Heating; 2. Pressing; 3. Pre-forging; 4. Final forging. At the corresponding positions of the J2 / J4 main journals, a pressing die is used to reduce the local cross-sectional area of ​​the billet and increase its overall length, optimizing the billet volume distribution and achieving a billet-making effect close to that of roll forging, thereby improving the material utilization rate of the four-balance crankshaft. The four-balance crankshaft structure is as follows: Figure 1 As shown, it includes W1 balance block 12, W4 balance block 13, W5 balance block 14 and W8 balance block 15.

[0023] This invention is applicable to the automatic line forging press pressing process of four-balance-block crankshafts for passenger vehicles, and includes the following steps: 1. After the billet is heated, it is held by the stepping beam clamp fingers of the automatic line and placed in the pressing mold 6; 2. The forging press slide descends; 3. The upper die 2 contacts the blank under the action of the slider; 4. Press forming; 5. The slider rises; 6. Press the upper mold 2 back to the top dead center; 7. Ejection system lifting and clamping step components; 8. Automatic line step beam clamping finger clamping step component.

[0024] The pressing die of the present invention includes an upper die and a lower die, such as... Figure 4 As shown.

[0025] The upper mold includes: upper seat 1, clamping upper mold 2, positioning key 3, and screw I 4.

[0026] The lower mold includes: lower base 5, clamping lower mold 6, lower ejector rod support 7, ejector rod support pressure block 8, ejection mechanism 9, screw II 10 and screw III 11; The upper clamping die 2 is fastened to the upper seat 1 by screw I4. The upper clamping die 2 and the upper seat 1 are positioned in the front-to-back direction by positioning key 3, and in the left-to-right direction by the pressing positioning surface I1-2 of the upper seat 1, as shown below. Figure 11 , Figure 12 As shown in the figure. This positioning method effectively limits the front-to-back / left-to-right displacement of the upper clamping die 2. The position of the upper seat front-to-back positioning keyway 1-1 on the upper seat 1 is shown in the figure. The clamping die keyway 2-1 and the clamping die extrusion positioning surface 2-2 on the upper clamping die 2 are as shown in the figure. Figure 12 As shown.

[0027] The lower clamping die 6 is fastened to the lower base 5 by screws III11. The die bodies at both ends of the lower clamping die 6 are relatively thin; opening keyways would affect the die strength and pose a risk of cracking. Therefore, the keyways are designed into the lower clamping die 6. Figure 10 Position. The lower die 6 and the lower seat 5 are positioned in the front-to-back direction by the lower seat's front-to-back positioning keys 5-2, and in the left-to-right direction by the extrusion positioning surface II 5-3 of the lower seat 5. Figure 9 , Figure 10 As shown. The stroke of the lower push rod support 7 is limited within the groove on the bottom surface of the lower seat 5 by the push rod support pressure block 8 and screw II 10. The position of the upper push rod hole I 5-1 on the lower seat 5 is as follows. Figure 9 As shown. The positions of the ejector pin hole II 6-1, the keyway 6-2, the extrusion positioning surface 6-3, and the clamping finger slot 6-5 of the lower clamping die 6 are as follows. Figure 10 , Figures 14-15 As shown.

[0028] The ejection mechanism 9 consists of a lower ejector rod a, a lower ejector rod spring b, a spring guide post c, an ejector rod pressure block d, and a screw e. Figure 6 As shown. The spring guide post c passes through the limiting groove on the push rod block d via the lower push rod a, as... Figure 12As shown, the limiting position is achieved. The spring guide post c is installed in the limiting groove of the lower push rod a (limiting groove 9-1 of spring guide post C), the lower push rod spring b is sleeved on the spring guide post c, and the push rod pressure block d is fixed to the lower push rod a by screw e.

[0029] The ejection mechanism 9, along with the ejector rod support 7 and the ejector rod support pressure block 8, forms a clamping step ejection system. When the ejection system moves upward, the lower ejector rod support 7, pushed by the mold body ejector rod, drives the ejection mechanism 9 upward. The lower ejector rod spring b is compressed under force, and its top end is limited by the ejector rod hole end face F of the lower seat 6. The lower ejector rod a continues to move upward, passing through the clamping lower mold cavity 5 to lift the clamping step component, as... Figure 7 , Figure 8 As shown; after the ejection action is completed, the lower ejector rod support 7 returns to its initial position under the restoring force of the lower ejector rod spring b. After the clamping step is completed, the equipment slider rises, and the clamping step component is lifted and clamped away by the clamping fingers.

[0030] like Figure 1 As shown, J1 / J2 / J3 / J4 / J5 are main journals 1-5, P1 / P2 / P3 / P4 are connecting rod journals 1-4, D1 is the thrust surface diameter, and D2 is the main journal diameter.

[0031] The clamping mold adopts a concave-convex structure.

[0032] The 6-cavity mold of the pressing die is divided into cavities that participate in forming and cavities that do not participate in forming.

[0033] Cavities that do not participate in the forming process, such as Figure 18 As shown, a design using a circular cross-section, inclined plane, and large fillet is employed. The circular cross-section positions the blank in the left-right direction during clamping. The diameter of the circular cross-section of the cavity (2R) = the diameter of the blank D + 5~10mm; the angle of the inclined plane is between 15° and 20° to facilitate smooth demolding of the clamping step parts; the value of the large fillet R120 is generally 15-25mm to facilitate smooth demolding of the clamping step parts.

[0034] The mold closing height H = blank diameter D + 20~30mm. The lower clamping mold 6 has slots at both ends to prevent interference between the clamping fingers and the lower clamping mold 6 when gripping the clamping step parts. Figure 14 As shown.

[0035] Participating in the forming of the cavity, such as Figure 17 , Figure 19As shown, a design using a clamping boss and a bevel is employed. The bevel angle in this area is approximately 1°-3° smaller than that of the bevel angle of the non-forming cavity. The smaller the bevel angle, the more significant the change in blank volume at the boss position during clamping, the larger the increase in blank length A, and the greater the difficulty in demolding the clamped part. The radius R2 at the root of the clamping boss is generally 20-25mm. The clamping boss corresponds to the main journal position of the four-balance crankshaft J2 / J4. The mold closing height H1 / H2 is determined by the material volume required for the final forging of the main journal area of ​​the four-balance crankshaft J2 / J4. The diameter D1 of the thrust surface near the main journal J4 is greater than the diameter D2 of the main journal. The thrust surface requires more material for final forging. Based on the principle of constant volume, the mold closing height H1 at this position should be slightly greater than the diameter D1 of the thrust surface to prevent folding due to insufficient material during die forging. Based on experience, H1 = D1 + 1-2mm is sufficient; the mold closing height H2 at the main journal J2 position is D2 + 6-10mm. The higher the boss height, the smaller the mold closing height H1 / H2, the more significant the change in blank volume at the boss position during clamping, the greater the increase in blank length A, and the more significant the improvement in material utilization. The positions of inclined plane 19, large fillet R120, root fillet R221, and circular section 2R22 are as follows: Figures 17-19 As shown.

[0036] The height Y of the pressing die 6 is the same as the height of the pre-forging die, such as... Figure 20 As shown, ensure that the lifting height of the clamping step component and the pre-forging step component are consistent, and that the walking beam clamp fingers can hold the clamping step component and transfer it to the pre-forging step. The height A1 / C1 of the clamping boss 6-4 of the clamping lower die 6 is determined by the blank deformation amount (i.e., blank diameter D - die closing height H1 / H2). At section C, the height C1 of the clamping lower die 6 boss is greater than the blank deformation amount (blank diameter D - die closing height H1) / 2, and at section A, the height A1 of the clamping lower die 6 boss is greater than the blank deformation amount (blank diameter D - die closing height H2) / 2. To ensure stable deformation of the blank during the clamping process, the drop A1-C1 of the clamping boss 6-4 of the clamping lower die 6 is controlled between 0 and 10 mm. Since the clamping lower die 6 needs to have a long strip-shaped discharge groove and a positioning keyway, such as Figure 10 , Figure 14 As shown, to ensure the strength of the mold, the minimum wall thickness Y1 of the clamping lower mold 6 is between 25 and 30 mm in this invention.

[0037] The thickness T1 / T2 of the clamping boss 6-4 of the clamping die 6 is as follows: Figure 14 The thickness of the clamping boss 6-4 in the lower clamping die 6 is determined by the axial lengths L1 / L2 of the main journal region of the J2 / J4 crankshaft and the material volume required for final forging. The thickness T1 of the clamping boss 6-4 is equal to the axial length L1-1 to 3 mm of the J2 main journal, and the thickness T2 of the clamping boss 6-4 is equal to the axial length L2-1 to 3 mm of the J4 main journal. To ensure the strength of the clamping boss 6-4, a draft angle of 40° to 45° is designed in the thickness direction of the clamping boss 6-4.

[0038] The lower ejector rod a participates in the blank clamping and forming process in the cavity of the lower clamping mold 6. It needs to be designed according to the shape of the cavity of the lower clamping mold 6, with a gap of 0.2 to 0.3 mm on one side of the mold, to ensure that the blank will not drill into the gap of the lower ejector rod a during clamping, and the lower ejector rod can smoothly eject the clamping step part.

[0039] The clamping die 2 adopts a structure of a flat surface and a clamping boss. The flat surface does not participate in the blank forming process, and the diameter of both ends of the blank remains unchanged after forming, which facilitates automatic line stepping beam finger transfer. After the ejector pin lifts the workpiece, the stepping beam fingers clamp both ends of the workpiece and move it to the pre-forging station. The clamping boss 6-4 should be designed with a large rounded corner for a smooth transition to prevent defects such as creases during blank forming, which would affect the final forming of the forging. The rounded corner of the clamping boss 6-4 is generally between 15 and 25 mm.

[0040] The design principle of the upper die boss and the lower die boss is the same, such as... Figure 12 , Figure 15 , Figure 20 As shown, since a positioning keyway is required on the upper clamping die 2, in order to ensure the strength of the die, the minimum wall thickness Z1 of the upper clamping die 2 is between 50-60 mm in this invention.

[0041] The increased length A of the billet, such as Figure 3 As shown, the length of the blank is determined by the deformation amount of the blank (the diameter of the blank D - the mold closing height H1 / H2). In the application examples of this invention, the length of the blank increased by 10mm to 20mm.

[0042] The technical solution provided by this invention has a stable and reliable process and is suitable for mass production on an automated four-balance block crankshaft forging line.

[0043] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An automatic linear forging press clamping process suitable for four-balance-block crankshafts, characterized in that, Includes the following steps: A. After the billet is heated, it is held by the automatic line step beam clamp and placed in the pressing lower die (6); B. The forging press slide descends; C. The upper die (2) contacts the blank under the action of the slider; D. Press forming; E. The slider rises; F. Press the upper die (2) back to the top dead center; G. Ejection system lifting and clamping step components; H. Automatic line step beam clamp finger clamping pressing step component; A die for the automatic line forging press clamping process of a four-balanced crankshaft includes an upper die and a lower die. The upper die includes an upper seat (1), a clamping upper die (2), and a positioning key (3). The lower die includes a lower seat (5), a clamping lower die (6), a lower ejector rod support (7), an ejector rod support pressure block (8), and an ejection mechanism (9). The upper clamping die (2) is fastened to the upper seat (1). The upper clamping die (2) and the upper seat (1) are positioned in the front-to-back direction by positioning keys (3), and in the left-to-right direction by the extrusion positioning surface I (1-2) of the upper seat (1). The lower clamping die (6) is fastened to the lower seat (5). The keyway is designed on the lower clamping die (6). The lower clamping die (6) and the lower seat (5) are positioned in the front-to-back direction by the front-to-back positioning keys (5-2) of the lower seat (5), and in the left-to-right direction by the extrusion positioning surface II (5-3) of the lower seat (5). The ejection mechanism (9), the ejector rod support (7), and the ejector rod support pressure block (8) form the clamping step ejection. The system; the cavity of the clamping die (6) is divided into a cavity that participates in forming and a cavity that does not participate in forming; the cavity that does not participate in forming adopts a design of circular cross section combined with inclined surface combined with large rounded corner, the diameter of the circular cross section of the cavity = the diameter of the blank D + 5~10mm; the angle of the inclined surface (19) is between 15° and 20°, the value of the large rounded corner R1 (20) is generally 15-25mm, the mold closing height H = the diameter of the blank D + 20~30mm, and the clamping die (6) has slots at both ends; the cavity that participates in forming adopts a design of clamping boss (6-4) and inclined surface (19), the angle of the inclined surface is compared with that of the cavity that does not participate in forming. The slope angle is 1°-3° smaller, and the fillet radius R2 (21) at the root of the clamping boss (6-4) is 20-25mm; the clamping boss (6-4) corresponds to the main journal positions of the four balance block crankshaft J2 and J4. The mold closing height H1 is determined by the material volume required for the final forging of the main journal area of ​​the four balance block crankshaft J4, and the mold closing height H2 is determined by the material volume required for the final forging of the main journal area of ​​the four balance block crankshaft J2; the diameter of the thrust surface near the main journal J4 is D1 > the diameter of the main journal D2, and H1 = D1 + 1-2mm; the mold closing height H2 at the position of the main journal J2 is D2 + 6-10mm; the clamping lower mold (6) The height Y of the die body is the same as the height of the pre-forging die body. The heights A1 and C1 of the pressing boss of the pressing die (6) are determined by the amount of blank deformation. The height C1 of the pressing boss of the pressing die (6) at the C position is greater than the amount of blank deformation / 2. The amount of blank deformation is the blank diameter D - the closing height H1. The height A1 of the pressing boss of the pressing die (6) at the A position is greater than the amount of blank deformation / 2. The amount of blank deformation is the blank diameter D - the closing height H2. The drop A1-C1 of the pressing boss (6-4) of the pressing die (6) is controlled between 0 and 10 mm. The minimum wall thickness Y1 of the pressing die (6) is between 25 and 30 mm.The thickness T1 of the clamping boss (6-4) of the clamping die (6) is determined by the axial length L1 of the main journal region of the four balance block crankshaft J2 and the material volume required for final forging. The thickness T2 of the clamping boss (6-4) of the clamping die (6) is determined by the axial length L2 of the main journal region of the four balance block crankshaft J4 and the material volume required for final forging. The thickness T1 of the clamping boss (6-4) of the clamping die (6) is equal to the axial length L1 of the main journal of J2 - 1 to 3 mm, and the thickness T2 of the clamping boss is equal to the axial length L1 of the main journal of J4. The length L2-1~3mm, the draft angle of the pressing boss (6-4) in the thickness direction is designed to be 40°~45°; the pressing upper die (2) adopts a structure of plane and pressing boss (6-4), the fillet radius of the pressing boss (6-4) is generally between 15~25mm, the minimum wall thickness Z1 of the pressing upper die (2) is between 50-60mm, the length A of the increased blank is determined by the blank deformation, the blank deformation is the blank diameter D - the mold closing height H1, H2, the length of the increased blank is between 10mm~20mm.

2. The automatic linear forging press clamping process for a four-balance-block crankshaft according to claim 1, characterized in that: The upper clamping die (2) is fastened to the upper seat (1) by screw I (4), and the lower clamping die (6) is fastened to the lower seat (5) by screw III (11); the stroke of the lower push rod support (7) is limited in the groove on the bottom surface of the lower seat (5) by the push rod support pressure block (8) and screw II (10); the ejection mechanism (9) is composed of a lower push rod (a), a lower push rod spring (b), a spring guide column (c), a push rod pressure block (d) and a screw (e). The spring guide column (c) is limited by the limiting groove on the lower push rod (a) and the push rod pressure block (d). The spring guide column (c) is installed in the limiting groove of the lower push rod (a). The lower push rod spring (b) is sleeved on the spring guide column (c). The push rod pressure block (d) is fixed on the lower push rod (a) by screw (e).

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