Forging method of eccentric crankshaft

Abstract

The invention provides a forging method of an eccentric crankshaft, which comprises the following steps of: stamping a round bar-shaped blank to divide the round bar-shaped blank into a first part, a second part and a third part along the axial direction; the circular section of the round bar type blank in the radial direction is evenly divided into n fan-shaped parts with the central angle being theta in the circumferential direction, theta is larger than or equal to 30 degrees and smaller than or equal to 60 degrees, and 360 degrees are divided by theta to be an integer; the second part is placed on the lower V-shaped anvil, and the to-be-machined structures at different positions are rotated to the position below the upper flat anvil through the clamping piece; an upper flat anvil is used for carrying out pressing-down machining on the to-be-machined structure located on the lower portion so that the second part can be machined into an eccentric part, the extension length of the upper flat anvil in the radial direction of the second part is L, the chord length corresponding to each fan-shaped part is L1, the chord length corresponding to every two adjacent fan-shaped parts is L2, and L is larger than or equal to L1 and smaller than or equal to L2; and drawing out and finishing the first part and the third part. According to the scheme, the machining efficiency of the eccentric part can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of forging processing, and more particularly to a forging method for an eccentric crankshaft. Background Art

[0002] With the increasing demand for large crankshafts in the industrial field, traditional crankshaft forging technologies face many challenges. At present, the forming of crankshaft forgings mainly adopts two methods: die forging and open die forging. Among them, die forging is suitable for the production of small crankshafts, and for large-sized crankshafts, only the open die forging method can be used for manufacturing.

[0003] The existing open die forging technology first pre-forges and stretches the blank into a square structure, then forges it using an upper flat anvil and a lower platform, and then uses an upper flat and lower V-shaped anvil or upper and lower flat anvils to round it to form an eccentric part, and finally stretches it to produce the finished product. However, the above method requires multiple tooling changes when processing the eccentric part, which not only increases the operation difficulty but also prolongs the manufacturing cycle, thus affecting the production efficiency of the eccentric part. Summary of the Invention

[0004] The problem solved by the present invention is how to improve the production efficiency of the eccentric part.

[0005] To solve the above problems, the present invention provides a forging method for an eccentric crankshaft.

[0006] The present invention provides a forging method for an eccentric crankshaft, including: imprinting a round bar blank to axially divide the round bar blank into a first part, a second part, and a third part; evenly dividing the circular cross-section of the round bar blank in the radial direction into n fan-shaped parts with a central angle of θ, and the outer peripheral walls of the second part corresponding to every two adjacent fan-shaped parts are a group of structures to be processed, where 30° ≤ θ ≤ 60° and 360° divided by θ is an integer; placing the second part on a lower V-shaped anvil, clamping one end of the round bar blank through a clamping member, driving the round bar blank to rotate along its own axis, so that the structures to be processed at different positions rotate to the lower part of the upper flat anvil; using the upper flat anvil to perform pressing processing on the structure to be processed located below to process the second part into an eccentric part, where the extension length of the upper flat anvil along the radial direction of the second part is L, the chord length corresponding to each fan-shaped part is L1, and the chord length corresponding to two adjacent fan-shaped parts is L2, and L1 ≤ L ≤ L2; performing stretching and finishing on the first part and the third part.

[0007] Optionally, the step of evenly dividing the circular cross-section of the round bar blank in the radial direction into n sector parts with a central angle of θ along the circumferential direction specifically includes: according to the preset forging requirement information, calculating to drive the round bar blank to rotate C times along its own axis in a counterclockwise and clockwise alternating manner, where C = ((360° / θ) - 2) * n, and C is an even number, and n is the number of rounds for the round bar blank to rotate one week along its own axis.

[0008] Optionally, the step of calculating to drive the round bar blank to rotate C times along its own axis in a counterclockwise and clockwise alternating manner specifically includes: driving the round bar blank to rotate counterclockwise P times, and the angles of the counterclockwise rotation of the round bar blank are successively from θ to ((360° / θ) - 3) * θ, P is an even number and P ≤ 1 / 2 * ((360° / θ) - 2); driving the round bar blank to rotate clockwise Q times, Q = P, and the angles of the clockwise rotation of the round bar blank are successively from 2 * θ to ((360° / θ) - 2) * θ.

[0009] Optionally, after driving the round bar blank to rotate a total of C times along its own axis in a counterclockwise and clockwise alternating manner, the method further includes: according to the preset forging requirement information, determining the eccentric circular cross-section of the eccentric part in the radial direction of the round bar blank, so that the diameter of the eccentric circular cross-section in the vertical direction coincides with the diameter of the circular cross-section in the vertical direction; respectively measuring the diameters of the circular cross-section and the eccentric circular cross-section, and taking the diameter of the circular cross-section in the vertical direction as the reference line, calculating the difference H between the diameters corresponding to each θ when the circular cross-section and the eccentric circular cross-section rotate successively from the reference line.

[0010] Optionally, after calculating the difference H between the diameters corresponding to each θ when the circular cross-section and the eccentric circular cross-section rotate successively from the reference line, the method further includes: calculating the reduction amount X of the upper flat anvil under the difference in diameter corresponding to each θ, X = H / n, and the units digit of X is rounded up when it is 0 or 5.

[0011] Optionally, the step of using the upper flat anvil to perform a reduction process on the workpiece structure located below to process the second part into an eccentric part specifically includes: when the round bar blank rotates counterclockwise to rotate the workpiece structures at different positions below the upper flat anvil, the clamping member controls the round bar blank to move from the first part towards the third part, so that the upper flat anvil performs a reduction on the parts of the workpiece structure arranged successively in the direction from the third part towards the first part.

[0012] Optionally, the method of using the upper anvil to press down the structure to be processed located below so as to process the second part into an eccentric part specifically includes: when the round rod-shaped blank rotates clockwise to rotate the structure to be processed at different positions below the upper anvil, the clamping member controls the round rod-shaped blank to move from the third part toward the first part, so that the upper anvil presses down the parts of the structure to be processed that are arranged sequentially in the direction from the first part to the third part.

[0013] Optionally, the overlap amount between the upper flat anvil and the structure to be processed is between 10% and 15%.

[0014] Optionally, after using the upper flat anvil to press down the structure to be processed below to process the second part into an eccentric part, the method further includes: using the upper flat anvil to press down the first part and the third part.

[0015] Optionally, before stamping the round bar blank, the process also includes: sequentially heating the steel ingot, pressing the jaws, chamfering, gas cutting the bottom of the water nozzle, upsetting, stretching with upper and lower wide flat anvils, and chamfering the octagonal rounding, so as to process the steel ingot into the round bar blank.

[0016] The beneficial effects of the forging method of the eccentric crankshaft of the present invention are:

[0017] The round bar blank is embossed to form a three-section blank structure, which is convenient for effectively reducing the excess generated by forging in subsequent processing, ensuring the flatness of the end face, and providing stable support for the round bar blank through the lower V-shaped anvil. The upper flat anvil is used as a forming tool, and the radial extension length L of the upper flat anvil is set between L1 and L2, so as to ensure stability during the pressing process, and the circular cross-section is divided into multiple structures to be processed along the circumferential direction, so as to facilitate the subsequent processing of the structures to be processed at different positions, thereby reducing the processing difficulty. In addition, each structure to be processed can be accurately rotated and positioned through the clamping part, thereby improving the processing accuracy of the round bar blank. In summary, the present invention uses the structure of the upper flat anvil and the lower V-shaped anvil to undertake the second part, and uses the upper flat anvil to process the structures to be processed at different positions. In this way, there is no need to replace the processing tooling, which not only reduces the operating difficulty of the processing device, but also shortens the manufacturing cycle, thereby improving the production efficiency of the eccentric part. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic flow chart of a forging method for an eccentric crankshaft provided in an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the difference distribution between a circular cross section and an eccentric circular cross section at different angles provided in an embodiment of the present invention;

[0020] Figure 3 Schematic diagram of the first machining during the first-round machining provided by the embodiment of the present invention;

[0021] Figure 4 Schematic diagram of the second machining during the first-round machining provided by the embodiment of the present invention;

[0022] Figure 5 Schematic diagram of the third machining during the first-round machining provided by the embodiment of the present invention;

[0023] Figure 6 Schematic diagram of the fourth machining during the first-round machining provided by the embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the fifth machining during the first-round machining provided by the embodiment of the present invention;

[0025] Figure 8 Schematic diagram of the sixth machining during the first-round machining provided by the embodiment of the present invention;

[0026] Figure 9 Schematic diagram of the seventh machining during the first-round machining provided by the embodiment of the present invention;

[0027] Figure 10 Schematic diagram of the second machining during the first-round machining provided by the embodiment of the present invention;

[0028] Figure 11 Schematic diagram of the anvil misalignment movement of the forging method of the eccentric crankshaft provided by the embodiment of the present invention;

[0029] Figure 12 Schematic diagram after embossing of the round bar blank provided by the embodiment of the present invention;

[0030] Figure 13 Schematic structural diagram during embossing of the round bar blank provided by the embodiment of the present invention;

[0031] Description of reference numerals:

[0032] Round bar blank 10, first part 11, second part 12, third part 13, pliers handle 14, circular cross-section 15, eccentric circular cross-section 16,

[0033] Sector part 20,

[0034] Lower V-shaped anvil 30,

[0035] Clamping member 40,

[0036] Upper flat anvil 50,

[0037] Triangular auxiliary tool 60,

[0038] Axial direction X of the round bar blank, radial direction Y of the round bar blank. Detailed implementation manners

[0039] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not used to limit the protection scope of the present invention.

[0040] As used herein, the term "including" and its variants are open-ended, that is, "including but not limited to"; the term "based on" is "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiment". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence relationship of the functions performed by these devices, modules or units.

[0041] It should be noted that the modifications of "one" and "plural" mentioned in the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly stated in the context, it should be understood as "one or more".

[0042] As Figures 1 to 13 shown, the present invention provides a forging method for an eccentric crankshaft, including:

[0043] S100: Imprint the round bar blank 10 to axially divide the round bar blank 10 into a first part 11, a second part 12 and a third part 13;

[0044] S200: Uniformly divide the circular cross-section 15 of the round bar blank 10 in the radial direction into n sector parts 20 with a central angle of θ, and the outer peripheral walls of the second part 12 corresponding to every two adjacent sector parts 20 are a group of structures to be processed, where 30° ≤ θ ≤ 60° and θ is a common divisor of 360°;

[0045] S300: Place the second part 12 on the lower V-shaped anvil, clamp one end of the round bar blank 10 through the clamping member 40, and drive the round bar blank 10 to rotate along its own axis so that the structures to be processed at different positions rotate below the upper flat anvil 50;

[0046] S400: Use the upper flat anvil 50 to perform a pressing process on the structure to be processed located below to process the second part 12 into an eccentric part. Here, the extension length of the upper flat anvil 50 along the radial direction of the second part 12 is L, the chord length corresponding to each sector part 20 is L1, and the chord length corresponding to two adjacent sector parts 20 is L2, where L1 ≤ L ≤ L2;

[0047] S500: Perform cogging and sizing on the first part 11 and the third part 13.

[0048] In this embodiment, chamfer and trim the eccentric part processed from the second part 12 until the finished product requirements are met.

[0049] In this embodiment, X is the axial direction of the round bar billet 10, and Y is one of the diameter directions of the round bar billet 10.

[0050] In this embodiment, a clamp handle 14 is provided at one end of the third part 13 away from the first part 11, and the clamping member 40 is clamped and fixed to the clamp handle 14.

[0051] In this embodiment, a triangular auxiliary tool 60 can be arranged below the round bar billet 10, and then by driving the round bar billet 10 to move, the triangular part of the triangular auxiliary tool 60 is aligned with the upper flat anvil 50, and the upper flat anvil 50 is used to press down on the round bar billet 10. During the pressing process, an impression is gradually formed. The impression depth in this embodiment is one-third of the diameter difference between the circular cross-section 15 and the eccentric circular cross-section 16.

[0052] In this embodiment, rotational drive means periodically changing the processing orientation of the round bar billet 10. Specifically, the clamping end of the manipulator can be used in cooperation with a servo motor to achieve precise angle control, and the cumulative error caused by single-direction processing can be eliminated by alternately rotating counterclockwise and clockwise, which can improve the processing accuracy of the eccentric part.

[0053] In this embodiment, the size of the upper flat anvil 50 is between the chord length of a single sector and the chord length formed by combining adjacent sectors. This not only ensures that the upper flat anvil 50 can cover the target area in a single processing, but also prevents the edge of the upper flat anvil 50 from contacting the non-processing area, resulting in a situation where the local position cannot be effectively forged.

[0054] In this embodiment, the heating temperature for cogging and sizing is selected as 1250 ± 10 °C, and the holding time ≥ 16H.

[0055] In this embodiment, the round rod blank 10 is embossed to form a three-section blank structure, which is convenient for effectively reducing the excess generated by forging in subsequent processing and ensuring the flatness of the end face. The lower V-shaped anvil provides stable support for the round rod blank 10, and the upper flat anvil 50 is used as a forming tool. The radial extension length L of the upper flat anvil 50 is set between L1 and L2, so as to ensure stability during pressing. The circular cross-section 15 is divided into a plurality of sector-shaped portions 20 using a common divisor angle of 30° to 60° at the central angle of the circle. The outer peripheral wall of the second part 12 corresponding to each two adjacent sector-shaped portions 20 is a group of structures to be processed, ensuring the symmetry and continuity of the plurality of structures to be processed, thereby facilitating the subsequent processing of the structures to be processed at different positions, reducing the processing difficulty. In addition, each structure to be processed can be precisely rotated and positioned through the clamping member 40, thereby improving the processing accuracy of the round rod blank 10. In summary, this embodiment utilizes the structure of the upper flat anvil 50 and the lower V-shaped anvil to support the second part 12, and simultaneously utilizes the upper flat anvil 50 to process the structures to be processed at different positions. This eliminates the need to replace processing tools, which not only reduces the operating difficulty of the processing device, but also shortens the manufacturing cycle, thereby improving the production efficiency of the eccentric part.

[0056] like Figure 2 As shown, optionally, the circular cross-section 15 of the round rod blank 10 in the radial direction is evenly divided into n sector-shaped portions 20 with a central angle of θ along the circumferential direction, specifically comprising: according to the preset forging requirement information, calculating the number of times the round rod blank 10 is rotated along its own axis in alternating counterclockwise and clockwise directions for a total of C times, wherein C = ((360° / θ)-2)*n, and C is an even number, and n is the number of times the round rod blank 10 rotates along its own axis for one circle.

[0057] Among them, the preset forging requirement information refers to the geometric parameters and process conditions that need to be met during the forging process. Specifically, the material deformation coefficient, forging eccentricity, and anvil size data can be used for dynamic adjustment to determine the number and direction of rotation of the round rod blank 10.

[0058] In this embodiment, the number of rotations C is based on the number of sectors 20 required to cover the entire circumference. It is subtracted by 2 to eliminate unnecessary rotation processing at the head and tail, and multiplied by the number of rounds n to achieve multi-turn processing to eliminate errors caused by local deformation. Alternating counterclockwise and clockwise driving refers to changing the rotation direction of the blank in a preset order, which is used to balance the errors generated during processing in different directions.

[0059] In this embodiment, θ is set to 30°, and n is 4, so C is calculated to be 40, and the round bar blank 10 rotates 10 times per round.

[0060] Optionally, the calculation of driving the round bar blank 10 to rotate C times in sequence counterclockwise and clockwise along its own axis specifically includes: driving the round bar blank 10 to rotate counterclockwise P times, and the angles of the counterclockwise rotation of the round bar blank 10 are successively from θ to ((360° / θ) - 3) * θ, where P is an even number and P ≤ 1 / 2 * ((360° / θ) - 2); driving the round bar blank 10 to rotate clockwise Q times, Q = P, and the angles of the clockwise rotation of the round bar blank 10 are successively from 2 * θ to ((360° / θ) - 2) * θ.

[0061] It can be seen from this that the angles of counterclockwise rotation are successively from θ to ((360° / θ) - 3) * θ, which means that the angles of each counterclockwise rotation increase in an arithmetic progression to cover the positions of adjacent structures to be processed. The angles of clockwise rotation are successively from 2θ to ((360° / θ) - 2) * θ, which means that the angles of clockwise rotation start to increase from twice the value of θ to form a symmetric coverage area that cooperates with the counterclockwise rotation. By alternately performing counterclockwise rotation and clockwise rotation in each round of forging, it is ensured that the round bar blank 10 deforms uniformly under the state of two-way stress.

[0062] In this embodiment, the round bar blank 10 is driven to rotate counterclockwise 20 times and driven to rotate clockwise 20 times.

[0063] Optionally, after driving the round bar blank 10 to rotate C times in sequence counterclockwise and clockwise along its own axis, it further includes: determining the eccentric circular cross-section 16 of the eccentric part in the radial direction of the round bar blank 10 according to the preset forging requirement information, and making the diameter of the eccentric circular cross-section 16 in the vertical direction coincide with the diameter of the circular cross-section 15 in the vertical direction; respectively measuring the diameters of the circular cross-section 15 and the eccentric circular cross-section 16, and taking the diameter of the circular cross-section 15 in the vertical direction as the reference line, calculating the difference H between the diameters corresponding to each θ of rotation of the circular cross-section 15 and the eccentric circular cross-section 16 starting from the reference line.

[0064] In this embodiment, the eccentric circular cross-section 16 is determined to be in the radial direction of the circular cross-section 15, and its vertical diameter completely coincides with the vertical diameter of the circular cross-section 15, ensuring that they have a common measurement reference. The measuring device starts from the reference line position and measures the diameter every θ angle to obtain the corresponding diameter data sets of the circular cross-section 15 and the eccentric circular cross-section 16. By calculating the difference between the two sets of data at the same angle, the distribution of the H values in each sector area is generated, and this distribution directly reflects the deviation between the blank forming amount and the target value at different angles.

[0065] Such as Figure 2As shown, in this embodiment, when θ is set to 30°, values such as H0, H1, H2, H3, H4, and H5 can be measured and calculated at angular positions of 0°, 30°, 60°, 90°, 120°, 150°, etc., respectively, to form a complete deviation distribution map.

[0066] Through the above technical solution, aligning with the reference line ensures the consistency of multi-process measurement data. Calculating the difference by angle can reduce the deviation during the forging process, providing a direct basis for adjusting the reduction amount, thereby improving the regularity of the cross-sectional shape of the eccentric part, reducing the machining allowance in the subsequent finishing process, and enhancing the product size qualification rate.

[0067] Optionally, after calculating the difference H between the diameters corresponding to each rotation of θ from the reference line for the circular cross-section 15 and the eccentric circular cross-section 16, it further includes: calculating the reduction amount X of the upper flat anvil 50 under the difference in diameters corresponding to each θ, X = H / n, and rounding up when the units digit of X is 0 or 5.

[0068] In this embodiment, since the diameter of the circular cross-section 15 is 1800 mm and the diameter of the eccentric circular cross-section 16 is 1440 mm, the value of H0 is 360 mm at this time. It can be seen from the figure that it is symmetric about the center line at 30°, and the corresponding angular drop values are the same, with H1 being 340 mm, H2 being 285 mm, H3 being 200 mm, H4 being 105 mm, and H5 being 30 mm. For example, when H0 is 360 mm, the total forging reduction amount can be divided into 4 times of 90 mm for reduction, that is, the value of X is 4. For example, when H2 is 285 mm, the total forging reduction amount can be divided into 4 times of 75 mm for reduction.

[0069] As Figures 3 to 9 shown, the first-round hammer head is pressed down to a diameter target value of:

[0070] 1440 + (1 - 1 / 4)*H0 = 1400 + 3 / 4H0 = 1400 + 240 = 1710.

[0071] Where (1 - 1 / 4)*H0 (the units digit of the target value is rounded up according to 0 or 5). After each subsequent rotation during forging, the diameter target values of 1440 + (1 - number of rounds / 4)*H corresponding to the rotation angles of the next round (subsequent rounds 1, 2, 3, 4) are respectively:

[0072] 3 / 4H0 == 270 mm, and the corresponding reduction diameter target value is 1440 + 270 = 1710 mm;

[0073] 3 / 4H1 == 255 mm, and the corresponding reduction diameter target value is 1440 + 255 = 1695 mm;

[0074] 3 / 4H2 = 215 mm, the corresponding target value of the reduction diameter is 1440 + 215 = 1655 mm;

[0075] 3 / 4H3 = 150 mm, the corresponding target value of the reduction diameter is 1440 + 150 = 1590 mm;

[0076] 3 / 4H4 = 80 mm, the corresponding target value of the reduction diameter is 1440 + 80 = 1520 mm;

[0077] 3 / 4H5 = 25 mm, the corresponding target value of the reduction diameter is 1440 + 23 = 1465 mm.

[0078] The target value of the reduction diameter of the second-round hammer head is:

[0079] 2 / 4H0 == 180 mm, the corresponding target value of the reduction diameter is 1440 + 180 = 1620 mm;

[0080] 2 / 4H1 == 170 mm, the corresponding target value of the reduction diameter is 1440 + 170 = 1610 mm;

[0081] 2 / 4H2 = 145 mm, the corresponding target value of the reduction diameter is 1440 + 145 = 1685 mm;

[0082] 2 / 4H3 = 100 mm, the corresponding target value of the reduction diameter is 1440 + 100 = 1540 mm;

[0083] 2 / 4H4 = 55 mm, the corresponding target value of the reduction diameter is 1440 + 55 = 1495 mm;

[0084] 2 / 4H5 = 15 mm, the corresponding target value of the reduction diameter is 1440 + 15 = 1455 mm.

[0085] The target value of the reduction diameter of the third-round hammer head is:

[0086] 1 / 4H0 == 90 mm, the corresponding target value of the reduction diameter is 1440 + 90 = 1530 mm;

[0087] 1 / 4H1 == 85 mm, the corresponding target value of the reduction diameter is 1440 + 85 = 1525 mm;

[0088] 1 / 4H2 = 75 mm, the corresponding target value of the reduction diameter is 1440 + 75 = 1515 mm;

[0089] 1 / 4H3 = 50 mm, the corresponding target value of the reduction diameter is 1440 + 50 = 1490 mm;

[0090] 1 / 4H4 = 30 mm, the corresponding target value of the reduction diameter is 1440 + 30 = 1470 mm;

[0091] 1 / 4H5 = 10 mm, the corresponding target value of the reduction diameter is 1440 + 10 = 1450 mm.

[0092] The reduction of the fourth-round hammer head to the target diameter is:

[0093] The corresponding target values are all 1440 mm for final finishing.

[0094] Optionally, using the upper flat anvil 50 to perform reduction processing on the to-be-processed structure located below to process the second part 12 into an eccentric part specifically includes: when the round bar blank 10 rotates counterclockwise to make the to-be-processed structures at different positions rotate below the upper flat anvil 50, the clamping member 40 controls the round bar blank 10 to move from the first part 11 towards the third part 13, so that the upper flat anvil 50 performs reduction on the parts arranged in sequence on the to-be-processed structure in the direction from the third part 13 towards the first part 11.

[0095] Among them, the clamping member 40 controlling the round bar blank 10 to move from the first part 11 towards the third part 13 means adjusting the displacement along the axial direction of the blank through a mechanical fixture, and the upper flat anvil 50 performing reduction on the parts arranged in sequence on the to-be-processed structure in the direction from the third part 13 towards the first part 11 means that the processing trajectory of the upper flat anvil 50 gradually advances along the axial direction of the blank from the starting end of the third part 13 to the end of the first part 11. This sequential arrangement can avoid overlapping of adjacent areas during processing and maintain uniform distribution of the deformation amount.

[0096] In this embodiment, when the round bar blank 10 rotates counterclockwise to make the to-be-processed structures at different positions rotate below the upper flat anvil 50, the reduction sequence is from B to A.

[0097] Taking the first-round processing as an example:

[0098] As Figure 3 shown in a and 3b, the reduction sequence is in the direction from A to B, the reduction amount is 1 / 4Hn, that is, 360 / 4 = 90 mm, and the target diameter is 1710 mm.

[0099] As Figure 4 shown in a and 4b, the round bar blank 10 is rotated counterclockwise by 30°, the reduction sequence is in the direction from B to A, the reduction amount is 340 / 4 = 85 mm, and the target diameter is 1695 mm.

[0100] As Figure 5 shown in a and 5b, the round bar blank 10 is rotated clockwise by 60°, the reduction sequence is in the direction from A to B, the reduction amount is 340 / 4 = 85 mm, and the target diameter is 1695 mm.

[0101] As Figure 6 shown, rotate the round bar blank 10 counterclockwise by 90°, press down in the order from direction B to A, the amount of press down is 285 / 4 = 70 mm, and the target diameter value is 1655 mm.

[0102] As Figure 7 shown, rotate the round bar blank 10 clockwise by 120°, press down in the order from direction A to B, the amount of press down is 285 / 4 = 70 mm, and the target diameter value is 1655 mm.

[0103] As Figure 8 shown, rotate the round bar blank 10 counterclockwise by 150°, press down in the order from direction B to A, the amount of press down is 200 / 4 = 50 mm, and the target diameter value is 1590 mm.

[0104] As Figure 9 shown, rotate the round bar blank 10 clockwise by 180°, press down in the order from direction A to B, the amount of press down is 200 / 4 = 50 mm, and the target diameter value is 1590 mm.

[0105] Rotate the round bar blank 10 counterclockwise by 210°, press down in the order from direction B to A, the amount of press down is 105 / 4 = 25 mm, and the target diameter value is 1520 mm.

[0106] Rotate the round bar blank 10 clockwise by 240°, press down in the order from direction A to B, the amount of press down is 105 / 4 = 25 mm, and the target diameter value is 1520 mm.

[0107] Rotate the round bar blank 10 counterclockwise by 270°, press down in the order from direction B to A, the amount of press down is 30 / 4 = 5 mm, and the target diameter value is 1465 mm.

[0108] Rotate the round bar blank 10 clockwise by 300°, press down in the order from direction A to B, the amount of press down is 30 / 4 = 5 mm, and the target diameter value is 1465 mm.

[0109] The operation methods of the subsequent three rounds are the same as those of the first round, that is, in the second circle, align the H0 part with the hammer head again, press down by H0 / 4 = 90 mm, and then perform rotary forging. The target diameter values for pressing down in the subsequent rounds are operated according to the corresponding reduced target values above. Forge out the eccentric part and perform finishing.

[0110] In the process of forging, if the "outer eight" situation occurs, it can be carried out according to the Figure 10 schematic diagram shown, rotate the part with a large drop downward and perform anvil misalignment correction.

[0111] Due to the large diameter of this product, its H5 drop value is small, only 30 mm, allowing the number of passes to be reduced, and the reduction can be carried out in the second and fourth passes.

[0112] Optionally, using the upper flat anvil 50 to perform reduction processing on the underlying structure to be processed to process the second part 12 into an eccentric part specifically further includes: when the round bar blank 10 rotates clockwise to rotate the structures to be processed at different positions below the upper flat anvil 50, the clamping member 40 controls the round bar blank 10 to move from the third part 13 towards the first part 11, so that the upper flat anvil 50 performs reduction on the parts of the structure to be processed arranged in sequence in the direction from the first part 11 towards the third part 13.

[0113] Among them, the clamping member 40 controlling the round bar blank 10 to move from the third part 13 towards the first part 11 means adjusting the displacement along the axial direction of the blank through a mechanical fixture, and the upper flat anvil 50 performing reduction on the parts arranged in sequence in the direction from the first part 11 towards the third part 13 means that the processing trajectory of the upper flat anvil 50 gradually advances along the axial direction of the blank from the starting end of the first part 11 to the end of the third part 13. This sequential arrangement can avoid overlapping of adjacent areas and maintain a uniform distribution of the deformation amount.

[0114] In this embodiment, when the round bar blank 10 rotates clockwise to rotate the structures to be processed at different positions below the upper flat anvil 50, the anvil arrangement order is from A to B.

[0115] Such as Figure 3 shown, optionally, the anvil contact amount between the upper flat anvil 50 and the structure to be processed is between 10% and 15%.

[0116] Among them, the anvil contact amount refers to the ratio of the width of the contact area between the upper flat anvil 50 and the structure to be processed to the total width of the structure to be processed, and can be specifically achieved by adjusting the lateral movement distance of the upper flat anvil 50 or selecting anvils with different widths. In this embodiment, the anvil contact amount is limited between 10% and 15% to ensure that the effective contact area between the anvil and the blank can cover the area to be processed without causing overlapping deformation in adjacent areas due to excessive contact area.

[0117] Optionally, after using the upper flat anvil 50 to perform reduction processing on the underlying structure to be processed to process the second part 12 into an eccentric part, it further includes: using the upper flat anvil 50 to perform reduction on the first part 11 and the third part 13.

[0118] After multiple passes of rotary forging of the eccentric part, the overall round bar blank 10 remains within the hot working temperature range. The manipulator grips the round bar blank 10 to maintain its axial position, and moves the upper flat anvil 50 axially to the position corresponding to the first part 11 and the third part 13. By processing the first part 11 and the third part 13, continuous forging of three regions is completed in a single clamping state, thereby improving the processing efficiency.

[0119] Optionally, before embossing the round bar blank 10, it further includes: successively heating, pressing the jaws, chamfering, gas cutting the nozzle and the bottom of the ingot, upsetting, drawing out with upper and lower wide flat anvils, and chamfering and sizing to octagon the ingot to process it into a round bar blank 10.

[0120] In this embodiment, the ingot is heated in a furnace, the heating temperature is selected as 1250 ± 10 °C, and the holding time is ≥ 11H.

[0121] When upsetting the ingot, the heating temperature is selected as 1250 ± 10 °C, the holding time is ≥ 25H, and it is upset to a cylinder with a height of 1300 mm and a diameter of 3340 mm. Then the cylinder is drawn out to a cuboid of 1800 mm × 1800 mm × 3530 mm, the reduction amount of the upper flat anvil 50 is controlled to be ≥ 20%, the cuboid is chamfered and sized to an octagon to a cylinder with a diameter of 1800 mm and a height of 4500 mm, and the cylinder is embossed, and the embossing depth D1 = (1800 - 1440) / 3 = 120 mm.

[0122] Although the present invention is disclosed as above, the protection scope of the present invention 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 these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A forging method of an eccentric crankshaft, characterized in that, Including: Imprinting a round bar blank (10) to axially divide the round bar blank (10) into a first part (11), a second part (12), and a third part (13); Evenly dividing the circular cross-section (15) of the round bar blank (10) in the radial direction into n sector parts (20) with a central angle of θ in the circumferential direction. The outer peripheral walls of the second part (12) corresponding to every two adjacent sector parts (20) are a set of structures to be processed. Wherein, 30° ≤ θ ≤ 60°, and 360° divided by θ is an integer; Placing the second part (12) on a lower V-shaped anvil, clamping one end of the round bar blank (10) through a clamping member (40), and driving the round bar blank (10) to rotate along its own axis so that the structures to be processed at different positions rotate to below the upper flat anvil (50); Using the upper flat anvil (50) to perform a pressing process on the structure to be processed located below to process the second part (12) into an eccentric part. Wherein, the extension length of the upper flat anvil (50) in the radial direction of the second part (12) is L, the chord length corresponding to each sector part (20) is L1, and the chord length corresponding to two adjacent sector parts (20) is L2, L1 ≤ L ≤ L2; Performing drawing out and sizing on the first part (11) and the third part (13).

2. The forging method of the eccentric crankshaft according to claim 1, characterized in that, The evenly dividing the circular cross-section (15) of the round bar blank (10) in the radial direction into n sector parts (20) with a central angle of θ in the circumferential direction includes: According to preset forging requirement information, calculating to drive the round bar blank (10) to rotate C times along its own axis in a counterclockwise and clockwise alternating manner. Wherein, C = ((360° / θ) - 2) * n, and C is an even number, and n is the number of rounds of the round bar blank (10) rotating along its own axis for one week.

3. The forging method of the eccentric crankshaft according to claim 2, characterized in that, The calculating to drive the round bar blank (10) to rotate C times along its own axis in a counterclockwise and clockwise alternating manner includes: Driving the round bar blank (10) to rotate counterclockwise P times. The angles of the round bar blank (10) rotating counterclockwise are successively from θ to ((360° / θ) - 3) * θ. P is an even number and P ≤ 1 / 2 * ((360° / θ) - 2); Driving the round bar blank (10) to rotate clockwise Q times. Q = P, and the angles of the round bar blank (10) rotating clockwise are successively from 2 * θ to ((360° / θ) - 2) * θ.

4. The forging method of the eccentric crankshaft according to claim 2, characterized in that, After driving the round bar blank (10) to rotate C times in a counterclockwise and clockwise alternating manner along its own axis, it further includes: According to preset forging requirement information, determining an eccentric circular cross-section (16) of the eccentric part in the radial direction of the round bar blank (10), and making the diameter of the eccentric circular cross-section (16) in the vertical direction coincide with the diameter of the circular cross-section (15) in the vertical direction; Measure the diameters of the circular cross-section (15) and the eccentric circular cross-section (16) respectively. Taking the diameter of the circular cross-section (15) in the vertical direction as the reference line, calculate the difference H between the diameters of the circular cross-section (15) and the eccentric circular cross-section (16) corresponding to each rotation of θ from the reference line.

5. The forging method of the eccentric crankshaft according to claim 4, characterized in that, After calculating the difference H between the diameters of the circular cross-section (15) and the eccentric circular cross-section (16) corresponding to each rotation of θ from the reference line, it further includes: Calculate the reduction amount X of the upper flat anvil (50) under the difference in diameters corresponding to each θ, X = H / n, and perform a carry calculation when the units digit of X is 0 or 5.

6. The forging method of the eccentric crankshaft according to claim 1, characterized in that, The process of using the upper flat anvil (50) to press down the structure to be processed located below to process the second part (12) into an eccentric part includes: When the round bar blank (10) rotates counterclockwise to rotate the structure to be processed at different positions below the upper flat anvil (50), the clamping member (40) controls the round bar blank (10) to move from the first part (11) towards the third part (13), so that the upper flat anvil (50) presses down on the parts of the structure to be processed arranged in sequence in the direction from the third part (13) towards the first part (11).

7. The forging method of the eccentric crankshaft according to claim 1, characterized in that, The process of using the upper flat anvil (50) to press down the structure to be processed located below to process the second part (12) into an eccentric part includes: When the round bar blank (10) rotates clockwise to rotate the structure to be processed at different positions below the upper flat anvil (50), the clamping member (40) controls the round bar blank (10) to move from the third part (13) towards the first part (11), so that the upper flat anvil (50) presses down on the parts of the structure to be processed arranged in sequence in the direction from the first part (11) towards the third part (13).

8. The forging method of the eccentric crankshaft according to claim 1, characterized in that The anvil overlapping amount between the upper flat anvil (50) and the structure to be processed is between 10% and 15%.

9. The forging method of the eccentric crankshaft according to claim 1, characterized in that After using the upper flat anvil (50) to press down the structure to be processed located below to process the second part (12) into an eccentric part, it further includes: Using the upper flat anvil (50) to press down on the first part (11) and the third part (13).

10. The forging method of the eccentric crankshaft according to claim 1, characterized in that, Before embossing the round bar blank (10), it further includes: Heating the ingot, pressing the clamp mouth, chamfering, gas cutting the ingot bottom nozzle, upsetting, elongating with upper and lower wide flat anvils, and chamfering and circularizing the octagon in sequence to process the ingot into the round bar blank (10).

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