An integrated upsetting and bending forming process and forming mold for a large crankshaft with high balance weights

Abstract

This invention relates to an integrated upsetting and bending forming process and forming die for a large crankshaft containing a high balance block. The integrated upsetting and bending process includes simple machining blank preparation, local heating of a single crankshaft section, local horizontal upsetting, upsetting-bending coordinated deformation, rotating the blank according to the included angle of adjacent cranks, and forming the cranks sequentially until the overall crankshaft forming is completed. The bending and upsetting die includes: a bending die mechanism, including a lower bending die and an upper bending die, which, after being closed, can compress the connecting rod journal of the single crank under external pressure and perform bending processing; an upsetting and forging die mechanism, which has two sets and is symmetrically placed on both sides of the bending die mechanism; and a clamping mechanism that can clamp and protect the pre-formed and unformed main journals and connecting rod journals of the single crank on the multi-crankshaft part. Compared with the prior art, this invention achieves one-step full-fiber forming of a large medium-speed crankshaft containing a high balance block through an integrated upsetting and bending process.

Description

Technical Field

[0001] This invention belongs to the field of crankshaft forming technology and mold technology, and relates to an integrated upsetting and bending forming process and forming mold for a large crankshaft containing a high balance block. Background Technology

[0002] Large, medium-speed crankshafts used in ships or locomotives are core components that convert the vertical motion of cylinders into their own rotational motion. Mainstream forming technologies for crankshafts include free forging, die forging, and bending upsetting. However, for large marine crankshafts, integral die forging is difficult to achieve due to limitations in equipment tonnage and mold costs. Therefore, in actual production, all-fiber forging (RR, TR, and NTR methods) has become a commonly used method for manufacturing large crankshafts. For crankshafts with castings that significantly exceed the main journal counterweight (i.e., high counterweight), traditional bending upsetting methods have some limitations: during the bending process, the flow of the billet against the counterweight direction can lead to incomplete filling at the high counterweight of the crankshaft, failing to meet the dimensional requirements of the forging; to ensure filling at the high counterweight, the billet size needs to be increased, but this will cause a sharp increase in forming load, requiring compliance with the company's equipment tonnage.

[0003] To address the filling problem of balance blocks, a common approach in existing technologies is to employ a multi-stage pre-forging + final forging scheme. This involves pre-forging to initially distribute the billet, followed by final forging to improve filling and control flash and folding. Patent CN102744356A explicitly includes a pre-forging stage in the bending upsetting process to improve pre-forging quality and reduce the difficulty of final forging. However, the addition of the pre-forging process increases mold and processing costs. Furthermore, pre-forging introduces an additional heating step, subjecting the billet to repeated thermal cycles, leading to decreased material microstructure uniformity and significant performance dispersion, ultimately hindering the achievement of stable crankshaft microstructure quality. Utility model CN210121661U provides an upsetting mold for forming crankshaft crankpins, but lacks analysis of the upsetting process. Its forming capability is limited by the flow within the mold cavity, posing certain limitations for forming crankpins with higher balance blocks.

[0004] Finite element simulations revealed that for the forming of large, medium-speed crankshafts containing high-balance blocks, it is difficult to simultaneously satisfy high equipment loads and the filling requirements of the high-balance block crankshaft. Increasing the billet size and improving the filling at the balance block location would increase machining allowances and generate excessive flash at the connecting rod journal. Using closed-die forging, allowing the easily filled billet near the connecting rod journal to contact the die earlier and thus reflowing the billet, could easily lead to defects such as folding and result in higher forming forces. Therefore, ensuring good filling of the high-balance block in a single continuous forming process while meeting the enterprise's forming load requirements is crucial for crankshaft manufacturing.

[0005] Therefore, it is crucial to provide an integrated upsetting and bending forming process and mold that is applicable to large crankshafts with high balance blocks, has a wide range of applications, high filling capacity, and a large forming window. This invention is based on this principle. Summary of the Invention

[0006] The purpose of this invention is to provide a forming process and mold for a large medium-speed machine crankshaft containing a high balance block, and to achieve one-step full-fiber forming of the large medium-speed machine crankshaft containing a high balance block through an integrated upsetting and bending process.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a forming method for a large medium-speed engine crankshaft containing a high balance block, for machining a multi-crankshaft part composed of multiple single cranks connected in sequence, each single crank including a connecting rod journal, and a crank arm and a main journal respectively located on both sides of the connecting rod journal, the forming method comprising the following steps:

[0009] S1. Heat the single-crank blank to be formed on the multi-crankshaft part to the forging temperature and hold it at that temperature;

[0010] S2. Move the heated single-crank blank so that the main journals at both ends are in complete contact with the upsetting lower die. The section to be formed of the connecting rod journal is placed above the bending lower die and fits into the bending upper die. The remaining single-crank blanks are clamped and protected by a clamping mechanism.

[0011] S3. Under the action of the external press, the upsetting die mechanism on both sides of the single-crank billet is driven to move horizontally towards the center at a different speed, so as to squeeze the curved arm section of the single-crank billet to be formed, so that it flows in the circumferential direction and undergoes upsetting deformation.

[0012] S4. When the horizontal movement in S3 reaches the preset displacement, the vertical movement of the bending upper die is started, and the bending upper die is controlled to move downward at a constant speed. At the same time, the horizontal upsetting operation continues. When bending and upsetting are carried out simultaneously until the vertical displacement of the bending upper die reaches the design requirements, the processing and forming of a single crank of the multi-crankshaft part is completed.

[0013] S5. Demold and repeat the process of moving the multi-crankshaft part to the next single-crank blank.

[0014] Furthermore, in the multi-crankshaft component, there is a circumferential angle between two adjacent single cranks.

[0015] Furthermore, the blank of the multi-crankshaft part is first made according to the shape and size of the final formed product, combined with the machining allowance requirements, and based on the single-crank finite element simulation results, to increase the volume of the crank arm part, so as to ensure that the balance block of the crank arm part on the blank is completely filled.

[0016] In a second aspect, the present invention provides a forming mold for a large medium-speed engine crankshaft containing a high balance block, the forming mold comprising:

[0017] The bending die mechanism includes a lower bending die fixed on the processing frame and an upper bending die that can move up and down. After the upper bending die and the lower bending die are closed, they can squeeze the connecting rod journal of the single crank under external pressure and perform bending processing.

[0018] The upsetting die mechanism has two sets, which are symmetrically arranged on both sides of the bending die mechanism. Each set of upsetting die mechanism includes an upper upsetting die and a lower upsetting die. The upper upsetting die has side cavities on both sides, and the upper part of the side cavities is open. The lower upsetting die is machined with a disc-shaped cavity for accommodating the crank arm. When the upper upsetting die and the lower upsetting die are closed, the disc-shaped cavity and the lower bending die are in a closed state, and can perform upsetting deformation of the crank arm under horizontal pressure.

[0019] The clamping mechanism includes a main journal clamp and a connecting rod journal clamp. The main journal clamp is configured to clamp and protect the main journal of the multi-crankshaft part that has been machined and the single-crank that is to be formed. The connecting rod journal clamp is configured to clamp and protect the connecting rod journal of the multi-crankshaft part that has been machined and the single-crank that is to be formed.

[0020] Furthermore, the upper bending die and the lower bending die are symmetrically structured along the central plane, and the upper bending die and the lower bending die also cooperate to form a circular cavity that matches the connecting rod journal. When the mold is closed, the connecting rod journal of the single crank being machined is in complete contact with the circular cavity.

[0021] Furthermore, the upper part of the bending die is provided with a top edge cavity for accommodating the balance block of the curved arm. The top edge cavity is also provided with an arc-shaped flow-blocking surface to allow the extruded blank to flow to both sides during the downward movement of the bending die. The bending die is provided with a conical sidewall, and the blank forms an open flash under the combined action of the conical sidewall and the upsetting die.

[0022] Furthermore, the bottom of the bending die is provided with an I-shaped groove for mounting with the processing frame.

[0023] Furthermore, the upsetting die mechanism and the clamping mechanism are both installed in the upsetting module that applies horizontal extrusion force to the upsetting die mechanism, and move horizontally together with the upsetting module.

[0024] Furthermore, both the main journal fixture and the connecting rod journal fixture are divided into two types corresponding to the formed single crank and the blank to be formed. The main journal fixture has a cavity for matching and clamping the main shaft, and the connecting rod journal fixture has a cavity for matching and clamping the connecting rod journal.

[0025] Furthermore, the outer diameter dimensions of the upsetting die mechanism and the fixture mechanism remain consistent.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) The simple machining and one-step bending upsetting process proposed in this invention replaces the pre-forging process with simple machining of the billet, reduces the cost of changing the mold, and can realize one-step forming of large cranks with high balance blocks, reduce flash, save materials and production time, and greatly improve production efficiency.

[0028] (2) The crankshaft bending upsetting forming die provided by the present invention optimizes the cavity and sets open flash, which can effectively control the shape of the forging and avoid insufficient filling of the high balance block crank; the stress state in the die cavity is balanced during the forming process, the metal flow line distribution of the forging is reasonable, and the forming load is effectively controlled.

[0029] (3) When forging subsequent crankshafts, the billet only needs to be heated again. During assembly, it can be rotated in conjunction with the fixture to achieve continuous forming of a set of molds for multi-crankshafts. Attached Figure Description

[0030] Figure 1 A schematic diagram of the component structure for a single crankshaft.

[0031] Figure 2 This is a schematic diagram of a single crankshaft blank, from left to right: left view, front view, and isometric view.

[0032] Figure 3 This is a front view of the crankshaft six-crank blank;

[0033] Figure 4 A schematic diagram of the bending upsetting die and the billet structure;

[0034] Figure 5 This is a schematic diagram of the upper bending die;

[0035] Figure 6 This is a schematic diagram of the lower bending die;

[0036] Figure 7 This is a schematic diagram of the upper upsetting die;

[0037] Figure 8 This is a schematic diagram of the lower upsetting die;

[0038] Figure 9 A schematic diagram of the main journal fixture;

[0039] Figure 10 A schematic diagram of the pre-formed crankshaft journal fixture (left) and the fixture for the pre-formed connecting rod journal section (right);

[0040] Figure 11This is a schematic diagram of the mold in the closed state;

[0041] Figure 12 This is a schematic diagram of the assembly of the die and the blank during the first turn of the forged crankshaft.

[0042] Figure 13 This is a schematic diagram of the crankshaft structure formed according to the present invention;

[0043] Figure 14 for Figure 13 AA sectional view.

[0044] Explanation of annotations in the diagram:

[0045] 1- Bending upper die, 101- Arc-shaped flow-blocking surface, 102- Conical open flash; 2- Bending lower die, 201- Crank arm groove, 202- I-shaped groove, 203- Circular cavity; 3- Left upsetting upper die; 4- Left upsetting lower die; 5- Billet; 6- Right upsetting upper die; 7- Right upsetting lower die; 8- Left main journal upper clamp; 9- Left main journal lower clamp; 10- Formed crank connecting rod journal upper clamp; 11- Formed crank connecting rod journal lower clamp; 12- Billet connecting rod journal to be formed section upper clamp; 13- Billet connecting rod journal to be formed section lower clamp; 14- Right main journal upper clamp; 15- Right main journal lower clamp; 16- Connecting rod journal; 17- Main journal; 18- Crank arm. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] Unless otherwise specified, the functional components or structures in the following embodiments or examples are conventional components or structures used in the art to achieve the corresponding functions.

[0050] To achieve one-step forming of large crankshafts with high balance blocks, this invention provides a forming mold for a large medium-speed engine crankshaft containing high balance blocks. This mold is used to process and form multi-crankshaft parts composed of multiple single cranks connected sequentially. Each single crank includes a connecting rod journal 16, and crank arms 18 and main journals 17 located sequentially on both sides of the connecting rod journal. (See also...) Figures 4 to 13 As shown, the forming mold includes:

[0051] The bending die mechanism includes a lower bending die 2 fixed on the processing frame and an upper bending die 1 that can move up and down. After the upper bending die 1 and the lower bending die 2 are closed, they can squeeze the connecting rod journal of the single crank under external pressure and perform bending processing.

[0052] The upsetting die mechanism has two sets, which are symmetrically arranged on both sides of the bending die mechanism. Each set of upsetting die mechanism includes an upper upsetting die and a lower upsetting die. The upper upsetting die has side cavities on both sides, and the upper part of the side cavities is open. The lower upsetting die is machined with a disc-shaped cavity for accommodating the crank arm. When the upper upsetting die and the lower upsetting die are closed, the disc-shaped cavity and the lower bending die are in a closed state, and can perform upsetting deformation of the crank arm under horizontal pressure.

[0053] The clamping mechanism includes a main journal clamp and a connecting rod journal clamp. The main journal clamp is configured to clamp and protect the main journal of the multi-crankshaft part that has been machined and the single-crank that is to be formed. The connecting rod journal clamp is configured to clamp and protect the connecting rod journal of the multi-crankshaft part that has been machined and the single-crank that is to be formed.

[0054] In some specific embodiments, the upper bending die 1 and the lower bending die 2 are symmetrically structured along their central plane. A circular cavity 203 is also formed between the upper bending die 1 and the lower bending die 2 to match the connecting rod journal. During die closing, the machining of the single-crank connecting rod journal is in complete contact with the circular cavity 203. Additionally, please refer to [further details omitted]. Figure 5 and Figure 6 As shown, the bending upper die 1 of the present invention can be roughly "door" shaped, while the bending lower die 2 has slideways on both sides of the part forming the circular cavity 203, which slide in cooperation with the two "feet" of the bending upper die 1. In this way, the bending upper die 1 can achieve good cooperation with the bending lower die 2 under the guidance of the slideways during the downward movement. At the same time, the bending lower die 2 has curved arm grooves 201 on both sides of the circular cavity 203 (connecting rod journal), which slide in cooperation with the protruding cavity of the upsetting lower die, so that when the upsetting lower die moves horizontally, the billet 5 is squeezed into the closed curved arm cavity.

[0055] In some specific embodiments, the upper part of the bending die 1 is provided with a top edge cavity for accommodating the balance block of the curved arm. The top edge cavity is also provided with an arc-shaped flow-blocking surface 101 to enable the extruded blank 5 to flow to both sides during the downward movement of the upper part of the bending die 1. At the same time, a conical open flash 102 is designed to accommodate excess metal while ensuring filling and reducing the forming load.

[0056] In some specific embodiments, the bottom of the bending lower die 2 is also provided with an I-shaped groove 202 for installation in conjunction with the processing frame.

[0057] In some specific embodiments, the upsetting die mechanism and the fixture mechanism are both installed within the upsetting module that applies horizontal extrusion force to the upsetting die mechanism, and move horizontally together with the upsetting module. Furthermore, the outer diameter dimensions of the upsetting die mechanism and the fixture mechanism are kept consistent, thus enabling the machining of different single cranks on multi-crankshaft parts using a single upsetting module.

[0058] In some specific embodiments, both the main journal fixture and the connecting rod journal fixture are divided into two types corresponding to the formed single crank and the blank to be formed. The main journal fixture has a cavity for clamping the main shaft, and the connecting rod journal fixture has a cavity for clamping the connecting rod journal. Preferably, as above, the distance between the cavities on the main journal fixture corresponding to the formed single crank and the blank to be formed is the displacement of the bending upper die 1 as it compresses the main journal to continue moving downward.

[0059] In another aspect, the present invention provides a method for forming a large medium-speed engine crankshaft containing a high balance block, which is implemented based on the forming mold described in the first aspect above, the forming method comprising the following steps:

[0060] S1. Heat the single-crank blank 5 to be formed on the multi-crankshaft part to the forging temperature and hold it at that temperature;

[0061] S2. Move the heated single-crank blank 5 so that the main journals at both ends of it are in complete contact with the upsetting lower die. The section to be formed of the connecting rod journal is placed above the bending lower die 2 and is fitted with the bending upper die 1. The remaining single-crank blanks are clamped and protected by a clamping mechanism.

[0062] S3. Under the action of the external press, the upsetting die mechanism on both sides of the single-crank blank 5 is driven to move horizontally towards the center at a different speed, so as to squeeze the curved arm section to be formed of the single-crank blank 5, so that it flows in the circumferential direction and undergoes upsetting deformation.

[0063] S4. When the horizontal movement in S3 reaches the preset displacement, the vertical movement of the bending upper die 1 is started, and the bending upper die 1 is controlled to move downward at a constant speed. At the same time, the horizontal upsetting operation continues. When bending and upsetting are carried out simultaneously until the vertical displacement of the bending upper die 1 reaches the design requirements, the processing and forming of a single crank of the multi-crankshaft part is completed.

[0064] S5. Demold and repeat the process of placing a single-crank blank on top of the multi-crankshaft part.

[0065] In some specific embodiments, in the multi-crankshaft component, there is an included angle along the circumference between two adjacent single cranks.

[0066] In some specific embodiments, the blank 5 of the multi-crankshaft part is first increased in volume according to the shape and size of the final formed product, combined with the machining allowance requirements, and based on the single-crankshaft finite element simulation results, to ensure that the balance block of the crankshaft part on the blank 5 is completely filled.

[0067] Each of the above implementation methods can be implemented individually, or in any combination of two or more without violating logic.

[0068] The above implementation methods will be described in more detail below with reference to specific embodiments.

[0069] Example 1:

[0070] For example Figures 1 to 3 The multi-crankshaft component shown is actually a six-crankshaft component, consisting of six single cranks connected sequentially and symmetrically distributed in the pattern of first crank-second crank-third crank-third crank-second crank-first crank, with adjacent cranks forming a 120° angle. Figure 13 As shown. Each single crank includes a connecting rod journal, and a crank arm and a main journal located sequentially on both sides of the connecting rod journal.

[0071] To obtain the aforementioned six-crankshaft part, the optimized process for simple machining and one-step bending and upsetting of a large six-crankshaft medium-speed machine provided in this embodiment specifically includes the following steps:

[0072] The first step is the design and pre-processing of billet 5. According to... Figure 3Based on the shape and dimensions of the six-crankshaft part shown, and considering machining allowances, the preliminary design of the blank 5 structure is performed. According to the finite element simulation results of a single crankshaft, it is determined whether the eight corners of the balance block of the crank arm are completely filled, and the machining allowances of the eight corners are measured. The volume of the crank arm portion in blank 5 is increased to ensure the balance block is completely filled and meets the machining allowance requirements. A tangent is drawn to the outer circle of the connecting rod journal at a direction ±50° to the vertical line, and the crank arm portion of blank 5 is cut to determine the final structure of blank 5. Each single-crankshaft blank 5 is symmetrically distributed along the centerline. The pre-machining methods for the two crank arms are the same. Excluding the third and fourth cranks, the pre-machined cut portions between each pair of cranks form a 120° angle.

[0073] The second step is to select the forming mold. For example... Figure 4 and Figure 11 As shown, the mold in this embodiment includes a bending mold mechanism and an upsetting mold mechanism, specifically including an upper bending mold 1, a lower bending mold 2, a left upsetting upper mold 3, a left upsetting lower mold 4, a right upsetting upper mold 6, and a right upsetting lower mold 7.

[0074] The left upsetting upper die 3 and the left upsetting lower die 4 are exactly the same as the right upsetting upper die 6 and the right upsetting lower die 7, and are symmetrically distributed. Each upsetting upper die has side cavities on both sides and an open design on the top, while the upsetting lower die has a disc-shaped cavity for accommodating and forming the curved arm, which is closed with the bending lower die 2 when the die is closed.

[0075] The upper bending die 1 and the lower bending die 2 are symmetrically structured along their central plane. The upper bending die 1 has an arc-shaped top cavity to accommodate the crank arm balance block. This cavity is designed to extrude the blank 5 to both sides during downward movement, allowing the balance block's sharp corners to be filled. A tapered open flash 102 is also designed to accommodate excess metal while ensuring filling, reducing the forming load. The lower bending die 2 has an I-shaped groove at its bottom for installation with the lower frame. The lower bending die 2 also has circular cavities 203 for connecting rod journals. When the die is closed, the connecting rod journals are in complete contact with the upper and lower circular cavities 203.

[0076] The third step is to select a fixture. For example... Figure 11 As shown, the fixture in this embodiment includes an upper fixture 8 for the left main journal, a lower fixture 9 for the left main journal, an upper fixture 10 for the formed crank connecting rod journal, a lower fixture 11 for the formed crank connecting rod journal, an upper fixture 12 for the section of the billet connecting rod journal to be formed, a lower fixture 13 for the section of the billet connecting rod journal to be formed, an upper fixture 14 for the right main journal, and a lower fixture 15 for the right main journal.

[0077] like Figure 9 As shown, the upper clamp 8 and lower clamp 9 of the left spindle journal have a cavity containing the spindle in the center. Figure 10As shown in (left), the upper fixture 10 and the lower fixture of the pre-formed crank connecting rod journal have cavities containing the pre-formed connecting rod journal. The distance between the center of the cavity and the center of the outer contour is the displacement of the bending die during downward movement; as shown in the left. Figure 10 As shown on the right, the upper fixture of the blank connecting rod journal to be formed section and the lower fixture of the blank connecting rod journal to be formed section have a cavity in the center containing the unformed connecting rod journal.

[0078] Step four, heating. Figure 2 The single-bend billet 5 shown is heated to the forging temperature by induction heating and held at that temperature for a certain period of time according to the process requirements.

[0079] The range of induction heating should preferably not exceed the length of a single bend.

[0080] The fifth step is to forge the first crutch.

[0081] (1) Positioning and assembly: such as Figure 12 As shown, the billet 5 in the heating furnace is moved onto the die by an overhead crane, so that the main shaft between the left flange and the first crank is in complete contact with the left upsetting die 4, the main journal between the first and second cranks is in complete contact with the right upsetting die 7, and the connecting rod journal of the second crank is in complete contact with the lower clamp of the billet connecting rod journal to be formed. The right end face of the upper clamp 10 and the lower clamp 11 of the formed crank connecting rod journal coincides with the left end face of the flange, serving as a flange plug. The section of the main journal to be formed between the second and third cranks is in complete contact with the lower clamp 15 of the right main journal. The upper clamp 8 and the lower clamp 9 of the left main journal are not assembled with the billet 5. The bending upper die 1 is attached to the section of the connecting rod journal to be formed of the first crank, and the bending lower die 2 is fixed on the lower frame. In addition, the upper clamp 12 and the lower clamp 13 of the billet connecting rod journal to be formed section are used to clamp the connecting rod journal area of ​​the single-crank billet to be formed later.

[0082] All the above-mentioned molds and fixtures are assembled in a left-right layout on the upsetting module that is driven to move horizontally by an external press, so as to achieve upsetting of the billet 5 curved arm by the horizontal movement of the upsetting modules on both sides.

[0083] (2) One-step bending and upsetting forming: Under the action of the press, the elbow pushes the upsetting modules on both sides to move horizontally towards the center at a variable speed. The left upsetting upper die 3, the left upsetting lower die 4, the left main journal upper clamp 8, the left main journal lower clamp 9, the formed crank connecting rod journal upper clamp 10, and the formed crank connecting rod journal lower clamp 11 move to the right at the same time. The right upsetting upper die 6, the right upsetting lower die 7, the billet connecting rod journal upper clamp 12, the billet connecting rod journal lower clamp 13, the right main journal upper clamp 14, and the right main journal lower clamp 15 move to the left at the same time, squeezing the crank arm billet 5 to flow circumferentially, causing it to undergo upsetting deformation.

[0084] After the horizontal movement reaches the designed displacement, the vertical movement of the upper bending die 1 is activated. The upper bending die 1 moves downward at a constant speed, while the lower bending die 2 remains stationary. Bending and upsetting are carried out simultaneously until the vertical displacement reaches the designed displacement. The die is in the closed state, and the first crankshaft forming is completed.

[0085] Step 6: Demolding and heating the second bend. Remove the forging from the mold cavity and transport it to the heating furnace for heating the second bend.

[0086] Step 7: Forge the second crutch.

[0087] (1) Positioning and assembly: The upper clamp 8 and lower clamp 9 of the left main journal are assembled with the main shaft between the first crank and the flange; the upper clamp 10 and lower clamp 11 of the formed crank connecting rod journal are assembled with the connecting rod journal of the formed first crank; the upper die 3 and lower die 4 of the left upsetting are assembled with the main shaft between the first and second cranks. The assembly of the remaining dies and blanks 5 is the same as that in the fifth step of forging the first crank.

[0088] (2) One-step bending and upsetting: The mold movement is the same as that of the first bend in the fifth step of forging.

[0089] The preformed crank connecting rod journal upper fixture 10, the preformed crank connecting rod journal lower fixture 11, and the bending upper die 1 and bending lower die 2 form a 120° angle.

[0090] Step 8: Forging the subsequent crank.

[0091] After the third forging is completed, the billet 5 needs to be turned over and placed after heating.

[0092] The mold and optimized process provided in this embodiment can realize one-step continuous forming of a large six-crankshaft with a high balance block, and the forged part fully meets the shape and size requirements.

[0093] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An integrated upsetting and bending forming process for a large crankshaft with a high balance block, used to process and form a multi-crankshaft part composed of multiple single cranks connected in sequence, each single crank including a connecting rod journal, and a crank arm and a main journal respectively located on both sides of the connecting rod journal, characterized in that, The forming process includes the following steps: S1. Heat the single-crank blank to be formed on the multi-crankshaft part to the forging temperature and hold it at that temperature; S2. Move the heated single-crank blank so that the main journals at both ends of it are in complete contact with the upsetting lower die of the upsetting die mechanism. The section to be formed of the connecting rod journal is placed above the bending lower die and fits into the bending upper die. The remaining single-crank blanks are clamped and protected by a clamping mechanism. S3. Under the action of the external press, the upsetting die mechanism on both sides of the single-crank billet is driven to move horizontally towards the center at a different speed, so as to squeeze the curved arm section of the single-crank billet to be formed, so that it flows in the circumferential direction and undergoes upsetting deformation. S4. When the horizontal movement in S3 reaches the preset displacement, the vertical movement of the bending upper die is started, and the bending upper die is controlled to move downward at a constant speed. At the same time, the horizontal upsetting operation continues. When bending and upsetting are carried out simultaneously until the vertical displacement of the bending upper die reaches the design requirements, the processing and forming of a single crank of the multi-crankshaft part is completed. S5. Demolding, and repeating the process of moving the multi-crankshaft part to the next single-crank blank; The upsetting die mechanism also includes an upsetting upper die. The upper part of the bending upper die is provided with a top edge cavity for accommodating the balance block of the curved arm. The top edge cavity is also provided with an arc-shaped flow-blocking surface to allow the extruded blank to flow to both sides during the downward movement of the bending upper die. A chamfer is provided above the arc-shaped flow-blocking surface, which together with the upsetting upper die forms a conical open flash when the die is closed.

2. The upsetting and bending integrated forming process for a large crankshaft with a high balance block according to claim 1, characterized in that, In the multi-crankshaft component, there is an included angle along the circumference between two adjacent single cranks.

3. The upsetting and bending integrated forming process for a large crankshaft with a high balance block according to claim 1, characterized in that, The blank of the multi-crankshaft part is first made according to the shape and size of the final product, combined with the machining allowance requirements, and based on the finite element simulation results of the single crankshaft, to increase the volume of the crank arm part, so as to ensure that the balance block of the crank arm part on the blank is completely filled.

4. A large crankshaft upsetting and bending integrated forming mold containing a high balance block, used for implementing the upsetting and bending integrated forming process as described in any one of claims 1-3, characterized in that, The forming mold includes: The bending die mechanism includes a lower bending die fixed on the processing frame and an upper bending die that can move up and down. After the upper bending die and the lower bending die are closed, they can squeeze the connecting rod journal of the single-crank under external pressure and perform bending processing. The upsetting die mechanism has two sets, which are symmetrically arranged on both sides of the bending die mechanism. Each set of upsetting die mechanism includes an upper upsetting die and a lower upsetting die. The upper upsetting die has side cavities on both sides, and the upper part of the side cavities is open. The lower upsetting die is machined with a disc-shaped cavity for accommodating the crank arm. When the upper upsetting die and the lower upsetting die are closed, the disc-shaped cavity and the lower bending die are in a closed state, and can perform upsetting deformation of the crank arm under horizontal pressure. The clamping mechanism includes a main journal clamp and a connecting rod journal clamp, wherein the main journal clamp is configured to clamp and protect the main journal of the multi-crankshaft part that has been machined and the single-crank that is to be formed, and the connecting rod journal clamp is configured to clamp and protect the connecting rod journal of the multi-crankshaft part that has been machined and the single-crank that is to be formed. The upper part of the bending die is provided with a top edge cavity for accommodating the balance block of the curved arm. The top edge cavity is also provided with an arc-shaped flow-blocking surface to allow the extruded blank to flow to both sides during the downward movement of the bending die. A chamfer is provided above the arc-shaped flow-blocking surface, which together with the upsetting die forms a conical open flash when the die is closed.

5. The upsetting and bending integrated forming mold for a large crankshaft containing a high balance block according to claim 4, characterized in that, The upper bending die and the lower bending die are symmetrically structured along the central plane. The upper bending die and the lower bending die also cooperate to form a circular cavity that matches the connecting rod journal. When the mold is closed, the single-crank connecting rod journal being machined is in complete contact with the circular cavity.

6. The integrated upsetting and bending forming mold for a large crankshaft with a high balance block according to claim 4, characterized in that, The bottom of the bending die is also provided with an I-shaped groove for installation in conjunction with the processing frame.

7. The integrated upsetting and bending forming mold for a large crankshaft with a high balance block according to claim 4, characterized in that, The upsetting die mechanism and the clamping mechanism are both installed in the upsetting module that applies horizontal extrusion force to the upsetting die mechanism, and move horizontally together with the upsetting module.

8. The integrated upsetting and bending forming mold for a large crankshaft with a high balance block according to claim 4, characterized in that, Both the main journal fixture and the connecting rod journal fixture are divided into two types, corresponding to the formed single crank and the blank to be formed. The main journal fixture has a cavity for matching and clamping the main shaft, and the connecting rod journal fixture has a cavity for matching and clamping the connecting rod journal.

9. The integrated upsetting and bending forming mold for a large crankshaft with a high balance block according to claim 4, characterized in that, The outer diameter dimensions of the upsetting die mechanism and the fixture mechanism are kept consistent.

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