A device for a three-throw eccentric crankshaft and an eccentric forging method

Abstract

The application provides a device for a three-throw eccentric crankshaft and an eccentric forging method, and a blank for supporting a three-throw eccentric crankshaft during forging, the three-throw eccentric crankshaft comprising a crankshaft part, a center throw part, a first side throw part and a second side throw part, the device for the three-throw eccentric crankshaft comprising a first support part and a second support part, the first support part being provided with a first support groove, the first support groove supporting the first side throw part, the second support part being provided with a second support groove, the second support groove supporting the second side throw part, and the center throw part being horizontally supported by the first support groove and the second support groove, so that the forging effect is better, manual intervention is reduced, the first side throw part, the center throw part and the second side throw part are equiangular and equidistant, the positioning precision of the finished product is high, the dependence on manual experience is reduced, and the degree of automation is improved.

Description

Technical Field

[0001] This invention relates to the field of eccentric crankshaft forging technology, and more particularly to an apparatus and eccentric forging method for a three-crank eccentric crankshaft. Background Technology

[0002] As the transmission core of a high-power power system, the large three-crankshaft with eccentricity has a complex structure, uneven mass distribution, and large eccentricity, which puts extremely high demands on the positioning accuracy, clamping stability and forming uniformity during the forging process.

[0003] Currently, the forging of large three-crankshaft eccentric crankshafts mainly relies on general forging platforms and manual adjustment and positioning, lacking the support of special tooling. In actual production, hoisting and simple support are often used for operation. Because it relies heavily on manual experience, the angle positioning is inaccurate, the forging quality is unstable, and the forgings are prone to displacement, twisting and deformation during the forging process, which leads to low production efficiency and makes it difficult to meet the manufacturing requirements of high efficiency and high consistency. Summary of the Invention

[0004] This invention provides an apparatus and an eccentric forging method for a three-crankshaft eccentric crankshaft, in order to solve the technical problems of low positioning accuracy and unstable forging quality of the three-crankshaft eccentric crankshaft.

[0005] This invention provides an apparatus and an eccentric forging method for a three-crankshaft. The apparatus for the three-crankshaft supports the blank of the three-crankshaft during forging. The three-crankshaft includes a crankshaft portion, a central crank portion, a first side crank portion, and a second side crank portion. The central crank portion, the first side crank portion, and the second side crank portion are all fixedly connected to the crankshaft portion. The apparatus for the three-crankshaft includes a first support member and a second support member. The first support member has a first support groove that supports the first side crank portion. The second support member has a second support groove that supports the second side crank portion. The support of the first support groove and the second support groove makes the upper surface of the central crank portion horizontal.

[0006] In one embodiment of the present invention, the first support member and the second support member are the same.

[0007] In one embodiment of the present invention, both the first support groove and the second support groove are V-shaped grooves.

[0008] In one embodiment of the present invention, the first support member includes a first support surface and a second support surface, both of which are in contact with the first side bend, and the angle between the first support surface and the second support surface is a right angle. The second support member includes a third support surface and a fourth support surface, both of which are in contact with the second side bend, and the angle between the third support surface and the fourth support surface is a right angle.

[0009] In one embodiment of the present invention, the first supporting surface has an angle of 30 degrees with the horizontal plane, and the second supporting surface has an angle of 60 degrees with the horizontal plane. The third support surface has an angle of 30 degrees with the horizontal plane, and the fourth support surface has an angle of 60 degrees with the horizontal plane.

[0010] In one embodiment of the present invention, the first support surface, the second support surface, the third support surface and the fourth support surface are all subjected to heat treatment.

[0011] In one embodiment of the present invention, the thickness of the first support member is greater than the thickness of the first side bend, and the thickness of the second support member is greater than the thickness of the second side bend.

[0012] In one embodiment of the present invention, the first support member further includes a limiting stop bar, the limiting stop bar including a limiting surface near the first side bend, the limiting surface being perpendicular to the horizontal plane.

[0013] In one embodiment of the present invention, both the first support groove and the second support groove are rounded.

[0014] An eccentric forging method for multi-crankshafts, employing the aforementioned apparatus for three-crankshafts, includes the following process: After the billet of the three-crank eccentric crankshaft is forged by cutting the shoulder to the three-crank billet size, the billet of the three-crank eccentric crankshaft is heated to the initial forging temperature and then hoisted onto the device for the three-crank eccentric crankshaft by a lifting device. The first side crank is supported by the first support member of the device for the three-crank eccentric crankshaft, and the second side crank is supported by the second support member of the device for the three-crank eccentric crankshaft. The positioning limits the first side bend and the second side bend, ensuring that the first side bend corresponds to the cavity of the first support mold and the second side bend corresponds to the cavity of the second support mold. The thickness of the first support is greater than the thickness of the first side bend. The first support limits the change in the angle and outer contour of the first side bend. The thickness of the second support is greater than the thickness of the second side bend. The second support limits the change in the angle and outer contour of the second side bend. Calculate the reduction amount, and feed the billet of the three-crankshaft and the device for the three-crankshaft into a hot forging press. The hot forging press forges the upper end face of the central crank of the three-crankshaft, and performs multiple pre-forging and final forging to eccentrically press the central crank to the finished eccentric size. The hot forging press forges the remaining parts of the three-crankshaft eccentric crankshaft. After forging, the crankshaft is straightened, removed, and finished to become a finished product.

[0015] The beneficial effects of this invention are as follows: The device and eccentric forging method for a three-crankshaft proposed in this invention effectively support the first and second side cranks by setting a first support member and a second support member, respectively, while ensuring that the upper end face of the central crank is horizontal. This results in better forging effect and more stable forging quality. By reducing manual intervention, it ensures that the first side crank, the central crank, and the second side crank are equiangular and equidistant, thereby producing a product with high positioning accuracy. This reduces reliance on manual experience, improves automation, and ultimately increases production efficiency, meeting the manufacturing requirements of high efficiency and high consistency. It is particularly suitable for the free forging or die forging production of three-crankshaft eccentric crankshafts weighing several tons, used in equipment such as marine engines, large compressors, and heavy-duty diesel engines. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] In the attached diagram: Figure 1 This is a perspective view of a device for a three-crankshaft eccentric crankshaft provided in one embodiment of the present invention; Figure 2 This is a front view of a device for a three-crankshaft eccentric crankshaft provided in one embodiment of the present invention; Figure 3 This is a side view of a device for a three-crankshaft eccentric crankshaft provided in one embodiment of the present invention; Figure 4 This is a front view of the first support member provided in one embodiment of the present invention; Figure 5 This is a perspective view of the first support member provided in one embodiment of the present invention; Figure 6 This is a front view of the second support member provided in one embodiment of the present invention; Figure 7 This is a perspective view of the second support member provided in one embodiment of the present invention.

[0018] The attached figures are labeled as follows: 100, First support member; 110, First support surface; 120, Second support surface; 130, First support groove; 140, Limiting stop bar; 141, Limiting surface; 200, Second support member; 210, Third support surface; 220, Fourth support surface; 230, Second support groove; 300, Three-crank eccentric crankshaft; 310, Crankshaft section; 320, Central crank section; 330, First side crank section; 340, Second side crank section. Detailed Implementation

[0019] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0020] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0022] like Figures 1 to 7As shown, a device for a three-crank eccentric crankshaft is used to support the blank of the three-crank eccentric crankshaft 300 during forging. The three-crank eccentric crankshaft 300 includes a crankshaft portion 310, a central crank portion 320, a first side crank portion 330, and a second side crank portion 340. The central crank portion 320, the first side crank portion 330, and the second side crank portion 340 are all fixedly connected to the crankshaft portion 310. The central crank portion 320 is located between the first side crank portion 330 and the second side crank portion 340. The phase angles of the three cranks of the finished three-crank eccentric crankshaft 300—the central crank portion 320, the first side crank portion 330, and the second side crank portion 340—are 120 degrees apart to ensure uniform ignition intervals. The three-crank eccentric crankshaft 300 is a crankshaft specifically designed for three-cylinder reciprocating machinery. The connecting rod journals on the three cranks are all designed with an eccentric structure. This design changes the piston stroke or top dead center position relative to a standard concentric crankshaft. Its main engineering purpose is to achieve variable compression ratio, optimize engine balance, or meet special motion requirements. The central crank 320, the first side crank 330, and the second side crank 340 in the three-crank eccentric crankshaft 300 are all composed of a connecting rod journal and crank arms connecting their two sides. The three cranks are arranged along the crankshaft axis, and the uniform 120-degree phase angle ensures the balance of the working sequence of the three cylinders (or three sets of pistons).

[0023] like Figure 1 and Figure 2 As shown, the device for the three-crankshaft eccentric crankshaft includes a first support 100 and a second support 200.

[0024] like Figure 4 and Figure 5As shown, the first support member 100 has a first support groove 130, which supports the first side bend 330. The first support groove 130 is a recess, and its shape is not limited here, including but not limited to a V-groove. Those skilled in the art will understand that the present invention uses any existing material that meets the requirements of high strength, high toughness, high heat fatigue resistance, and high wear resistance to manufacture the first support member 100, including but not limited to hot work die steel and high-toughness alloy structural steel. The first support groove 130 supports the first side bend 330 in a surface-to-surface contact manner. When the upper end face of the center bend 320 is forged by a hot forging press, the surface-to-surface contact between the first support groove 130 and the first side bend 330 reduces stress concentration. Simultaneously, the first support member 100 can better restrict and constrain the metal flow of the first side bend 330, thus regulating the shape of the three-bend eccentric crankshaft 300 blank. To improve the strength and wear resistance of the contact surface, the surface of the first support groove 130 is nitrided and polished. In a nitrogen-rich atmosphere at a lower temperature, nitrogen atoms penetrate into the surface of the first support groove 130 to form a nitride layer with high hardness and high stability. As a result, the first support groove 130 and the first side bend 330 have a better contact effect. The first support member 100 can better restrict and constrain the metal flow of the first side bend 330, reduce the problem of folding and material accumulation between bends, reduce the amount of residual material in subsequent machining, and improve the material utilization rate.

[0025] like Figure 6 and Figure 7 As shown, the second support member 200 has a second support groove 230, which supports the second side bend 340. The material of the second support member 200 is not limited here, for example, it is hot work die steel and high toughness alloy structural steel. The shape of the second support groove 230 is not limited here, including but not limited to V-groove. In one embodiment of the present invention, the first support member 100 and the second support member 200 are both made of hot work die steel. The first support member 100 and the second support member 200 are the same, which reduces manufacturing costs and makes them highly substitutable. The first support member 100 and the second support member 200 can be quickly replaced after long-term operation.

[0026] like Figure 3As shown, the upper surface of the central bend 320 is made horizontal by the support of the first support groove 130 and the second support groove 230. When the upper end face of the central bend 320 of the three-bend eccentric crankshaft 300 is forged by a hot forging press, the first support groove 130 applies a reaction force to the first side bend 330, and the second support groove 230 applies a reaction force to the second side bend 340. On the one hand, this makes the phase angle between the central bend 320, the first side bend 330, and the second side bend 340 more precise, with a difference of 120 degrees. The first support member 100 can better restrict the metal flow of the first side bend 330, and the second support member 200 can better restrict the metal flow of the second side bend 340, thereby standardizing the shape of the three-bend eccentric crankshaft 300 blank, reducing the subsequent processing time of the first support member 100 blank and the second support member 200 blank, and improving the processing accuracy. On the other hand, the horizontal upper end face of the central bend 320 facilitates the forging operation of the hot forging press, eliminating the need to repeatedly adjust the blank angle.

[0027] The device for the three-crank eccentric crankshaft provides precise angle control, eliminating the need for repeated adjustments to the billet angle, reducing manual intervention and labor intensity. A single device for the three-crank eccentric crankshaft can be adapted to multiple three-crank eccentric crankshafts 300 of different specifications, exhibiting good versatility and expandability, and saving operation time. The device for the three-crank eccentric crankshaft is not only adapted to the three-crank eccentric crankshaft 600, but also to various models of multi-crank eccentric crankshafts, such as six-crank and nine-crank eccentric crankshafts, exhibiting good versatility and expandability. like Figure 1 As shown, both the first support groove 130 and the second support groove 230 are V-shaped grooves.

[0028] like Figure 1 and Figure 4 As shown, the first support member 100 includes a first support surface 110 and a second support surface 120. Both the first support surface 110 and the second support surface 120 are in contact with the first side bend 330, and the angle between the first support surface 110 and the second support surface 120 is a right angle.

[0029] like Figure 1 and Figure 6 As shown, the second support member 200 includes a third support surface 210 and a fourth support surface 220. Both the third support surface 210 and the fourth support surface 220 are in contact with the second side bend 340, and the included angle between the third support surface 210 and the fourth support surface 220 is a right angle.

[0030] like Figure 4 As shown, the first support surface 110 forms a 30-degree angle with the horizontal plane, and the second support surface 120 forms a 60-degree angle with the horizontal plane. Figure 6 As shown, the third support surface 210 has an angle of 30 degrees with the horizontal plane, and the fourth support surface 220 has an angle of 60 degrees with the horizontal plane. These angle settings ensure that when the upper surface of the central bend 320 is horizontal, the central bend 320, the first side bend 330, and the second side bend 340 are at equal angles and distances. The angle difference between two adjacent circumferential directions between the central bend 320, the first side bend 330, and the second side bend 340 is 120 degrees. This results in more accurate eccentricity forging, reduced difficulty in controlling the forging process, and more stable forging quality. Precise angle control is achieved, avoiding angle deviations during misalignment.

[0031] The first support surface 110, the second support surface 120, the third support surface 210, and the fourth support surface 220 are all subjected to heat treatment. This reduces the probability of deformation of the first support surface 110, the second support surface 120, the third support surface 210, and the fourth support surface 220 after multiple forging processes.

[0032] like Figure 2 As shown, the thickness of the first support member 100 is greater than the thickness of the first side bend 330, and the thickness of the second support member 200 is greater than the thickness of the second side bend 340. Figure 2 As shown, d1 represents the thickness of the first support member 100, d2 represents the thickness of the first side bend 330, d3 represents the thickness of the second support member 200, and d4 represents the thickness of the second side bend 340. That is, the thickness d1 of the first support member 100 is greater than the thickness d2 of the first side bend 330, and the thickness d3 of the second support member 200 is greater than the thickness d4 of the second side bend 340. By restricting and constraining the metal flow of the first side bend 330 through the first support member 100, the problem of material accumulation between folds and bends is reduced, the amount of residual material in subsequent machining is reduced, and the material utilization rate is improved.

[0033] like Figure 4 and Figure 5 As shown, the first support member 100 also includes a limiting stop 140, the limiting stop 140 including a limiting surface 141 near the first side bend 330, the limiting surface 141 being perpendicular to the horizontal plane.

[0034] Both the first support groove 130 and the second support groove 230 are rounded. This reduces the probability of cracking at the bottom of the first support groove 130 and the second support groove 230 due to stress concentration. Before rounding, an additional allowance needs to be left for the finished product of the three-crank eccentric crankshaft 300.

[0035] An eccentric forging method for multi-crankshafts, employing the aforementioned apparatus for three-crankshafts, includes the following process: After the billet of the three-crank eccentric crankshaft 300 is forged by cutting the shoulder to form the three-crank billet size, the billet of the three-crank eccentric crankshaft 300 is heated to the initial forging temperature and then hoisted onto the device for the three-crank eccentric crankshaft by a lifting device. The first side crank 330 is supported by the first support member 100 of the device for the three-crank eccentric crankshaft, and the second side crank 340 is supported by the second support member 200 of the device for the three-crank eccentric crankshaft. The positioning limits the first side bend 330 and the second side bend 340, ensuring that the first side bend 330 corresponds to the mold cavity of the first support member 100 and the second side bend 340 corresponds to the mold cavity of the second support member 200. The thickness of the first support member 100 is greater than the thickness of the first side bend 330, thereby limiting the change in angle and outer contour size of the first side bend 330. The thickness of the second support member 200 is greater than the thickness of the second side bend 340, thereby limiting the change in angle and outer contour size of the second side bend 340. Based on the dimensions of the first support member 100 and the second support member 200, as well as the finished dimensions of the three-crank eccentric crankshaft 300, the reduction amount is calculated. The billet of the three-crank eccentric crankshaft 300 and the device for the three-crank eccentric crankshaft are fed into a hot forging press. The hot forging press forges the upper end face of the central crank portion 320 of the three-crank eccentric crankshaft 300, and performs multiple pre-forging and final forging passes until the central crank portion 320 reaches the finished eccentric size. The first support member 100 and the second support member 200 act as a support frame, and together with the lifting device, they move the three-crank eccentric crankshaft 300, moving the remaining parts of the three-crank eccentric crankshaft 300 other than the central crank portion 320 to be forged to the area directly below the hot forging press, where the hot forging press forges the remaining parts of the three-crank eccentric crankshaft 300. After forging, the shaft is straightened and the three-crank eccentric crankshaft 300 is removed, thus becoming the finished product.

[0036] The hot forging press forges the upper surface of the center bend 320 with a flat anvil to offset it, and the center bend 320 is offset to the process dimension under pressure.

[0037] The beneficial effects of this invention are: This invention proposes a device and eccentric forging method for a three-crankshaft with eccentricity. It provides a standard angle positioning fixture, which, by setting a first support 100 and a second support 200, effectively supports the first side crank 330 and the second side crank 340 respectively, ensuring that the upper surface of the central crank 320 is horizontal. This results in better forging of the central crank 320, eliminating the need for repeated adjustments to the billet angle, reducing manual intervention, and ensuring that the first side crank 330, the central crank 320, and the second side crank 340 are equiangularly and equally spaced. Precise control of angles and eccentricities leads to high positioning accuracy in the forged product, reducing reliance on manual experience, increasing automation, and ultimately improving production efficiency, meeting the requirements of high efficiency and high performance. To meet the manufacturing requirements of consistency, when the hot forging press forges the upper surface of the center bend 320, since the first support surface 110 and the second support surface 120 are both in contact with the first side bend 330, the first support member 100 and the second support member 200 correspondingly standardize the shape of the first side bend 330, thereby improving the overall blank appearance of the three-bend eccentric crankshaft 300. The shape and size of the first support member 100 and the second support member 200 are equal, reducing manufacturing costs. At the same time, the first support member 100 and the second support member 200 can be quickly replaced after long-term operation. In addition, the present invention can reduce the number of forging passes, reducing one pass compared with the traditional dieless eccentric forging, reducing the occupation of the heating furnace and natural gas consumption. It can be adapted to various models of multi-crank eccentric crankshafts, such as six-crank eccentric crankshafts and nine-crank eccentric crankshafts, and has good versatility and expandability. It is especially suitable for free forging or die forging production of equipment such as marine engines, large compressors, and heavy-duty diesel engines, as well as three-crank eccentric crankshafts 300, six-crank eccentric crankshafts and nine-crank eccentric crankshafts weighing several tons.

[0038] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A device for a three-crank eccentric crankshaft, used to support the blank of a three-crank eccentric crankshaft (300) during forging, said three-crank eccentric crankshaft (300) comprising a crankshaft portion (310), a central crank portion (320), a first side crank portion (330), and a second side crank portion (340), said central crank portion (320), the first side crank portion (330), and the second side crank portion (340) being fixedly connected to the crankshaft portion (310), characterized in that, The device for the three-crankshaft eccentric crankshaft includes: A first support member (100) is provided with a first support groove (130) which supports the first side bend (330). The first support member (100) includes a first support surface (110) and a second support surface (120). Both the first support surface (110) and the second support surface (120) are in contact with the first side bend (330), and the angle between the first support surface (110) and the second support surface (120) is a right angle. The second support member (200) has a second support groove (230) on it, which supports the second side bend (340). The second support member (200) includes a third support surface (210) and a fourth support surface (220). The third support surface (210) and the fourth support surface (220) are both in contact with the second side bend (340), and the angle between the third support surface (210) and the fourth support surface (220) is a right angle. The first support groove (130) and the second support groove (230) are both V-shaped grooves; the support of the first support groove (130) and the second support groove (230) makes the upper surface of the central bend (320) horizontal; The first support surface (110) has an angle of 30 degrees with the horizontal plane, and the second support surface (120) has an angle of 60 degrees with the horizontal plane; The third support surface (210) has an angle of 30 degrees with the horizontal plane, and the fourth support surface (220) has an angle of 60 degrees with the horizontal plane; The thickness of the first support member (100) is greater than the thickness of the first side bend (330), and the thickness of the second support member (200) is greater than the thickness of the second side bend (340).

2. The device for a three-crankshaft eccentric crankshaft according to claim 1, characterized in that, The first support member (100) and the second support member (200) are the same.

3. The device for a three-crankshaft eccentric crankshaft according to claim 1, characterized in that, The first support surface (110), the second support surface (120), the third support surface (210) and the fourth support surface (220) are all subjected to heat treatment.

4. The device for a three-crankshaft eccentric crankshaft according to claim 1, characterized in that, The first support member (100) further includes a limiting stop (140), the limiting stop (140) including a limiting surface (141) near the first side bend (330), the limiting surface (141) being perpendicular to the horizontal plane.

5. The device for a three-crankshaft eccentric crankshaft according to claim 1, characterized in that, Both the first support groove (130) and the second support groove (230) are rounded.

6. An eccentric forging method for a three-crankshaft eccentric crankshaft, employing the apparatus for a three-crankshaft eccentric crankshaft as described in any one of claims 1-5, characterized in that, The process includes the following: After the blank of the three-crank eccentric crankshaft (300) is forged to the size of the three-crank blank, the blank of the three-crank eccentric crankshaft (300) is heated to the initial forging temperature and then hoisted onto the device for the three-crank eccentric crankshaft by a lifting device. The first side crank (330) is supported by the first support member (100) of the device for the three-crank eccentric crankshaft, and the second side crank (340) is supported by the second support member (200) of the device for the three-crank eccentric crankshaft. Positioning limits the first side bend (330) and the second side bend (340) to ensure that the first side bend (330) corresponds to the first support groove (130) of the first support member (100) and the second side bend (340) corresponds to the second support groove (230) of the second support member (200). The thickness of the first support member (100) is greater than the thickness of the first side bend (330). The first support member (100) limits the change in the angle and outer contour size of the first side bend (330). The thickness of the second support member (200) is greater than the thickness of the second side bend (340). The second support member (200) limits the change in the angle and outer contour size of the second side bend (340). Calculate the reduction amount, and feed the billet of the three-crankshaft eccentric crankshaft (300) and the device for the three-crankshaft eccentric crankshaft into a hot forging press. The hot forging press forges the upper end face of the center crank (320) of the three-crankshaft eccentric crankshaft (300) and performs multiple pre-forging and final forging to eccentrically press the center crank (320) to the finished eccentric size. The hot forging press forges the remaining parts of the three-crankshaft eccentric crankshaft (300); After forging, straighten the three-crankshaft eccentric crankshaft (300), remove it, and finish the three-crankshaft eccentric crankshaft (300) to become the finished product.

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