A cold heading device for chassis bearing bolts of an automobile
By using a cold heading device with five molds in a continuous cold heading process, the problems of uneven material stress and low production efficiency in the forging process of automotive chassis bearing bolts have been solved, achieving high-quality, stable and efficient bolt forming.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG MINGTAI STANDARD PARTS CO LTD
- Filing Date
- 2026-04-30
- Publication Date
- 2026-05-29
Smart Images
Figure CN224294599U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of cold heading technology for bolts, specifically relating to a cold heading device for automotive chassis bearing bolts. Background Technology
[0002] The primary function of automotive chassis bearing bolts is to bear loads; they bear both axial and radial loads. Furthermore, bearing bolts play a role in balancing and stabilizing the engine and adjusting clearances for a smoother ride; they are crucial for maintaining the vehicle's structural stability and safe operation. Bearing bolts connect and secure different chassis components, each playing an irreplaceable role in its location, ensuring the vehicle's stability and safety during operation.
[0003] This automotive chassis bearing bolt has a cylindrical end with a central groove featuring a six-hole design for assembly, and a threaded end for fastening. The cylindrical and threaded ends differ significantly in depth. The bolt's forging process is complex, involving heating the blank to a red-hot state before hot stamping. This process results in uneven stress on the material, making it prone to cracking and deformation. Furthermore, the external burrs from the stamping process require machining for repair, leading to low production efficiency and poor finished product quality. Utility Model Content
[0004] In summary, to overcome the shortcomings of the prior art, this utility model provides a cold heading device for automobile chassis bearing bolts.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a cold forging device for automotive chassis bearing bolts, comprising a cutting mechanism, an ejection mechanism, a transfer mechanism, and five molds, wherein the cutting mechanism cuts the blank, the ejection mechanism lifts the blank, and the transfer mechanism moves and feeds the blank between the ejection mechanism and the five molds; the five molds include: a forging mold for initially shaping the initial blank and extruding and stretching the lower end to form a small-diameter rod portion; a forging mold for initially flattening the upper section of the first blank and forming positioning recesses at the upper and lower ends of the first blank respectively. The mold comprises a second upsetting mold, a third upsetting mold for further flattening the upper section of the second blank into a large-diameter cylinder and deepening the upper positioning recess, a fourth upsetting mold for deepening the upper positioning recess of the third blank into an upper groove and for extruding and stretching the upper section of the third blank as a whole, and a fifth upsetting mold for deepening the bottom of the upper groove of the fourth blank into a plum blossom hole and for extruding and stretching the upper section of the fourth blank as a whole; each of the five molds includes a lower mold and an upper mold, the lower mold including a lower mold shell, a lower mold core and a lower mold punch, the lower mold core being disposed inside the lower mold shell, and the lower mold core having a main mold cavity.
[0006] By adopting the above technical solution, through a continuous cold heading process of "forming a small-diameter rod at the lower end → initial shaping at the upper end → forming a large-diameter cylinder at the upper end → extruding the inner hole → extruding the plum blossom shape," product quality and consistency are significantly improved. The multi-step, progressive deformation of the billet in a cold state ensures precise dimensions, helps guide more uniform material flow, effectively reduces the risk of cracking or deformation caused by stress concentration, and makes the internal grain structure of the metal denser and the flow direction more rational, resulting in higher mechanical strength, hardness, and corrosion resistance. Regarding the forming of the inner hole and the plum blossom shape, the fourth and fifth stages ensure smooth material transfer rather than forced tearing, thus achieving "tear-free inner hole." The surface finish ensures the fullness of the plum blossom shape. During the second upsetting process, the upper and lower positioning recesses of the second blank, combined with the positioning function of the lower die punches of the third and fourth dies, help the blank to be accurately centered. When shifting into the die, it will not fall off or deviate, which improves the continuity and reliability of production, increases the stability of automated production, improves production efficiency, enhances the overall rigidity and stability of the die, reduces the risk of wear, and thus extends the service life of the die.
[0007] The present invention further comprises: the main mold cavity of the upsetting mold includes an upper forming cavity for forming the upper section of the first blank and a lower forming cavity for forming the lower section of the first blank; a transition cavity with a larger upper section and a smaller lower section is provided between the upper forming cavity and the lower forming cavity; the transition cavity is used to form the transition portion between the upper section of the second blank and the small-diameter rod; the upper end of the lower die punch extends into the lower forming cavity; the upper mold of the upsetting mold includes an upper die punch, the lower end of which extends into the upper forming cavity.
[0008] By adopting the above technical solution, the tapered transition cavity, which is larger at the top and smaller at the bottom, provides a smooth and guiding flow path for the material. This effectively avoids stress concentration and internal tearing risks caused by abrupt changes in cross-section when the blank is reduced from a large cross-section to a small diameter rod. It ensures continuous flow of metal fibers and lays a good foundation for subsequent processes. The lower die punch extends into the cavity to eject and form and support the lower end of the blank, while the upper die punch applies pressure from above. This two-way cooperation ensures accurate positioning and uniform stress on the blank during deformation, effectively preventing eccentricity or bending, and guaranteeing the straightness and dimensional accuracy of the small diameter rod after initial forming.
[0009] This utility model further comprises: the main mold cavity of the two-die forming mold includes an upper forming cavity for further forming the transition portion of the second blank and a lower forming cavity for further forming the small-diameter rod portion of the second blank and forming a chamfer at its lower end. The upper forming cavity is flared, wider at the top and narrower at the bottom, with a greater slope angle than the transition cavity of the first die, and a shallower depth than the transition cavity of the first die. The lower die punch is provided with a [missing information - likely a typo]. The lower conical protrusion forms a lower positioning recess at the lower end of the small-diameter rod of the second blank; the upper mold of the second upsetting mold includes a second mold upper mold core and a second mold upper mold punch. The second mold upper mold core includes a second mold upper mold cavity for initially flattening the upper section of the first blank. The second mold upper mold punch has an upper conical protrusion at one end corresponding to the second mold upper mold cavity for forming an upper positioning recess at the top of the second blank. The diameter of the lower conical protrusion is smaller than the diameter of the upper conical protrusion, and the depth of the second mold upper mold cavity is smaller than the depth of the first mold upper forming cavity.
[0010] By adopting the above technical solution, in the process from the first upsetting to the third upsetting, the transition section formed after the first upsetting requires final "upsetting" and shaping. The upper forming cavity of the second mold is a gradual "upsetting" transition of the transition section. The inclined plane angle of the upper forming cavity of the second mold is greater than that of the transition cavity of the first mold. Since this process requires preliminary flattening of the upper section of the blank (radial upsetting), the material will expand outward. The larger inclined plane angle allows the sidewall of the cavity to better guide and accommodate this radially flowing material, ensuring a smooth connection between the transition section and the upper upsetting section during the upsetting process, avoiding folds, cracks, or stress concentration, and forming a stable and reliable geometric transition. The depth of the upper forming cavity of the second mold is smaller. The shallower cavity, with its shallower depth, can constrain the upper material in the early stages of mold closing. Working in conjunction with the upper conical protrusion, it precisely controls the material to form an upward recess and to perform limited upsetting in all directions, reserving the correct material volume and deformation space for the third-stage "further flattening". The upper and lower conical protrusions simultaneously press out upper and lower positioning recesses, providing positioning features for the parts. The upper and lower positioning recesses provide crucial axial and coaxiality positioning references for subsequent processes, ensuring absolute consistency of the workpiece position in multi-stage processing. The diameter of the lower conical protrusion is smaller than that of the upper conical protrusion, while the larger diameter of the upper conical protrusion is beneficial for the rapid positioning of the upper mold in the third mold, and also for the positioning and forming of the inner hole in the subsequent process.
[0011] This utility model further comprises: the upper mold cavity of the second mold includes an upper mold cavity for forming a short frustum with a smaller upper end and a larger lower end on the upper section of the second blank, and a lower mold cavity for further shaping the upper section of the second blank into a long frustum with a smaller upper end and a larger lower end. The lower end diameter of the upper mold cavity is adapted to the upper end diameter of the lower mold cavity. The upper end diameter of the upper mold cavity is larger than the diameter of the upper mold cavity of the first mold. The depth of the upper mold cavity is 40%-70% of the depth of the lower mold cavity. The included angle of the inclined surface of the upper mold cavity is larger than the included angle of the inclined surface of the lower mold cavity.
[0012] By adopting the above technical solution, the upper cavity of the second mold first contacts the top of the blank. Its relatively shallow depth and large slope angle allow it to quickly converge, position, and initially roughen the top of the blank, rapidly completing the shape locking and material densification of the top of the blank. The lower cavity of the second mold then guides the upper section of the blank's main material to spread smoothly and evenly radially. (The lower cavity simultaneously receives material that has been initially compressed and continues to descend from the upper short truncated cone area and material replenished upwards from the lower rod section. The gentle slope greatly reduces the shear resistance of metal flow and the risk of internal shear band formation, ensuring smooth metal flow.) The design ensures a smooth transition between the upper and lower cavities of the second mold, preventing folding or internal cracking due to intense flow. The angle of the upper cavity's slope is greater than that of the lower cavity, preventing further flattening of the upper section of the third blank during the third upsetting process. The lower diameter of the upper cavity is matched to the upper diameter of the lower cavity, ensuring a precise depth ratio and smooth connection between these two functionally different areas. This results in a smooth transition in the blank's shape, continuous metal flow, and more uniform mold stress, preventing stress concentration caused by abrupt shape changes and extending mold life.
[0013] This utility model further comprises: the upper outer periphery of the transition cavity of the first mold is arc-shaped; the included angle of the inclined surface of the transition cavity of the first mold is a1, 60°≤a1≤120°; the inner diameter of the upper forming cavity of the first mold is D1; the inner diameter of the lower forming cavity of the first mold is d1, 0.5D1≤d1≤0.8D1; the included angle of the inclined surface of the upper forming cavity of the second mold is a2, 120°≤a2≤160°; the chamfer of the lower forming cavity of the second mold is a3, 30°≤a3≤50°; the upper mold of the second mold... The depth of the cavity is H2, and the depth of the lower molding cavity of the second mold is h2, 0.9H2≤h2≤1.1H2; the maximum diameter of the upper cavity of the second mold is d2, 1.17D1≤d2≤1.26D1, and the depth of the upper cavity of the second mold is H21, 0.3H2≤H21≤0.4H2; the maximum diameter of the lower cavity of the second mold is D2, 1.26D1≤D2≤1.36D1, and the depth of the lower cavity of the second mold is H22, 0.6H2≤H22≤0.7H2.
[0014] By adopting the above technical solution, the included angle of the inclined surface of the first mold transition cavity is a1, 60°≤a1≤120°, providing a transition slope from gentle to moderate. The upper arc transition eliminates sharp corners, avoiding shear or folding defects in the material during the initial flow stage, thus improving molding quality. The inner diameter ratio d1 / D1 (0.5-0.8) limits the section reduction rate, reducing the rod diameter to 50%-80% of the original diameter in one go, preventing material cracking due to excessive deformation. The maximum diameter of the second mold lower cavity is D2, with an inner diameter ratio of D2 / D1. (1.26-1.36) Due to the significant difference in diameter between the cylindrical and threaded ends of the automotive chassis bearing bolts, D1 selects an initial blank with a medium diameter. The lower section of the first mold is reduced to form a small-diameter (threaded) rod. The upper section of the second mold is initially upset (to prepare for subsequent upsetting and flattening to form the cylindrical end). This balances the deformation of axial tension and radial upsetting from the source, reducing the overall deformation difficulty and improving the forming quality. The inclined plane angle of the upper forming cavity of the second mold is a2, 120°≤a2≤160°, which is significantly larger than the angle a1. This provides a strong radial constraint on material flow, forcing the material to shift from axial extension to radial expansion, initiating the "upsetting" process, avoiding shearing or folding defects in the material, and improving the forming quality. The upper mold cavity of the second mold adopts a "short frustum (upper mold cavity of the second mold) + The composite design of "long truncated cone (lower cavity of the second mold)" precisely quantifies the upsetting deformation by increasing the diameter in a stepwise manner, while the proportional distribution of depth clarifies the deformation responsibility of each zone. This allows the upper section of the blank to complete precise volume pre-distribution in the second process. The upper cavity of the second mold gathers the material required to form the upper edge of the bolt head and the base of the recess, while the lower cavity of the second mold organizes the material required to form the main cone of the bolt head. This provides a preformed blank with a reasonable shape and precise volume for the next process (flattening the truncated cone formed in this process into a large-diameter cylinder). This fundamentally ensures that the head is full and without missing material during the final forging, significantly improving dimensional accuracy and consistency.
[0015] This utility model further comprises: the main mold cavity of the three-die mold includes a three-die upper forming cavity for further forming the upper section of the third blank into a large-diameter cylinder, a three-die transition cavity for further forming the transition part of the third blank, and a three-die receiving cavity for accommodating the small-diameter rod part of the third blank; the depth of the three-die upper forming cavity is less than the depth of the two-die upper mold cavity, and the diameter of the three-die upper forming cavity is greater than the maximum diameter of the two-die upper mold cavity; the three-die transition cavity is cylindrical with a chamfered outer circumference at the lower end, and the three-die transition cavity... The diameter is adapted to the diameter of the upper forming cavity of the three molds; the three mold receiving cavity is the same as the lower forming cavity of the two molds; the lower mold punch of the three molds has the same structure as the lower mold punch of the two molds; the upper mold of the three-die mold includes the upper mold core of the three molds, the upper mold core of the three molds includes the upper mold cavity of the three molds for forming the upper section of a large-diameter cylinder, the upper mold cavity of the three molds is provided with a positioning protrusion for further deepening the upper positioning recess, the maximum diameter of the positioning protrusion is smaller than the diameter of the upper mold cavity of the three molds, and the outer periphery of the upper end of the upper mold cavity of the three molds is provided with a chamfer.
[0016] By adopting the above technical solution, the diameter of the upper forming cavity of the third mold is larger than the maximum diameter of the upper mold cavity of the second mold, directly completing the radial expansion of the head. The depth is less than that of the upper mold cavity of the second mold, achieving axial compression of the head. This "one increase and one decrease" precisely corresponds to the deformation essence of "flattening and upsetting," transforming the frustum into a cylinder in the shortest path and most efficient way. The diameter of the transition cavity of the third mold matches the upper forming cavity, forming a smooth connection, guiding the material in the transition area between the head and the rod smoothly, avoiding folding or incomplete filling defects caused by right angles, ensuring full rounded corners and uniform stress distribution. From this sequence onwards, the diameter of the small-diameter rod in the third mold's receiving cavity (same as the second mold) is already fixed and no longer participates in deformation. The mold only processes the head of the blank, achieving focus and division of labor between processes, ensuring the stability of the rod's dimensions and... Consistency; The positioning protrusions set in the upper mold cavity of the third mold further deepen and shape the "upper positioning recess" prefabricated in the second sequence, making the shape and depth of the recess more precise, providing a more stable and accurate axial and circumferential positioning reference for all subsequent processes, ensuring the high consistency of multi-sequence processing, and at the same time further dispersing and compacting the material in the bottom area of the hole to the periphery, preparing for the fourth sequence forming of the inner hole; The structure of the lower mold punch of the third mold is the same as that of the lower mold punch of the second mold. The top shape of the lower mold punch matches the lower positioning recess at the lower end of the blank. At the moment of acceptance, the initial coaxial correction between the lower end of the blank and the lower mold punch is completed, ensuring that the initial position of the blank before entering the mold cavity is accurate, avoiding subsequent mold entry difficulties or mold off-center load impact caused by blank tilting, ensuring high-quality, high-efficiency, and large-scale stable operation.
[0017] This utility model further comprises: the main mold cavity of the four-die upsetting mold includes an upper forming cavity for extruding and stretching the large-diameter cylindrical part of the fourth blank and a receiving cavity for accommodating the small-diameter rod part of the fourth blank. The lower end of the upper forming cavity has the same shape as the transition cavity of the three-die. The receiving cavity has the same shape as the receiving cavity of the three-die. The lower die punch of the four-die has the same structure as the lower die punch of the two-die. The depth of the upper forming cavity of the four-die is greater than the depth of the upper forming cavity of the three-die. The upper die of the four-die upsetting mold includes an upper die punch. One end of the upper die punch extending into the upper forming cavity of the four-die is provided with a forming end for deepening the upper positioning recess of the fourth blank into an upper groove.
[0018] By adopting the above technical solution, the lower end of the upper forming cavity of the fourth mold has the same shape as the transition cavity of the third mold, and the shape of the fourth mold receiving cavity is the same as that of the third mold receiving cavity. The blank entering the fourth mold from the third stage can achieve a "seamless connection" between its lower head transition area and rod, perfectly fitting the corresponding part of the new mold cavity. This eliminates the repositioning error of the blank between molds, ensures absolute accuracy in axial positioning, and provides complete support for the formed part, avoiding deformation caused by suspension or poor support in subsequent processing, thus ensuring the stability of the achieved dimensions. The forming end of the upper mold punch is used to deepen the upper positioning recess into an upper groove, providing an extremely accurate and reliable axial and angular positioning reference for the final (fifth stage) forming of the plum blossom hole, ensuring the positional accuracy and perpendicularity of the plum blossom hole. Before final forming, the material at the bottom of the groove is further extruded to the periphery, providing a more reasonable material volume distribution for the formation of the plum blossom hole. This avoids incomplete hole filling or flash due to poor material flow during final forging. The deeper cavity allows the upper die punch to perform a longer extrusion stroke, effectively compacting the material, refining the grains, and eliminating any minor internal porosity that may have occurred in the previous process. This results in a denser head structure and improved mechanical properties (such as tensile and fatigue strength), ensuring that the head material is fully and uniformly stretched and formed. The lower die punch eliminates the repositioning error of the blank between the dies, ensuring absolute accuracy in axial positioning. The formed part is fully supported, preventing deformation caused by suspension or poor support during subsequent processing and ensuring the stability of the achieved dimensions.
[0019] This utility model further specifies that: the inner diameter of the upper forming cavity of the first mold is D1, the inner diameter of the upper forming cavity of the third mold is D3, 1.25D1≤D3≤1.45D1, the depth of the accommodating cavity of the third mold is h3, the depth of the upper forming cavity of the third mold is H3, 0.83h3≤H3≤0.92h3; the depth of the upper forming cavity of the fourth mold is H4, 0.99h3≤H4≤1.13h3, the depth of the upper groove of the fourth blank is L4, 1.63L4≤H4≤2.1L4, and the diameter of the forming end is D4, 0.67D3≤D4≤0.77D3.
[0020] By adopting the above technical solution, the final upsetting expansion rate of the head body is precisely controlled within the range of 25% to 45%, avoiding extreme upsetting in one or two upsettings. This prevents material instability, folding, or mold stress concentration caused by excessive deformation. The moderate, step-by-step expansion rate allows the metal fibers to flow radially in an orderly and uniform manner, which is conducive to forming a dense, defect-free head structure and high molding quality; H3 during the third upsetting. Slightly smaller than h3 means that the small-diameter rod has sufficient "wrapping" length in the mold, so that the rod will not become unstable and bend when the head is subjected to huge upsetting force, thus ensuring the straightness of the forming. When upsetting four times, H4 is about 1.6 to 2.1 times that of L4, which means that when the upper die punch reaches the deepest stroke point, there is still enough length of blank above its working section to be tightly wrapped by the mold cavity and extend axially. This prevents the material at the top of the groove from "bulging" outward or folding due to insufficient constraint under the extrusion of the punch, providing smooth guidance and reducing internal shearing, thereby forming a high-quality deep groove with smooth sidewalls and a full bottom.
[0021] This utility model further comprises: the main mold cavity of the five-die upsetting mold includes an upper forming cavity for extruding and stretching the large-diameter cylindrical part of the fifth blank and a receiving cavity for accommodating the small-diameter rod part of the fifth blank. The lower end of the upper forming cavity of the five-die has the same shape as the transition cavity of the three-die. The receiving cavity of the five-die has the same shape as the receiving cavity of the three-die. The lower die punch of the five-die has the same structure as the lower die punch of the two-die. The depth of the upper forming cavity of the five-die is less than the depth of the upper forming cavity of the four-die. The upper die of the five-die upsetting mold includes an upper die punch of the five-die. One end of the upper die punch of the five-die extends into the upper forming cavity of the five-die and is provided with a forming protrusion for forming a plum blossom hole.
[0022] By adopting the above technical solution and fully inheriting the positioning and support system of the previous three sequences (identical transition cavity, receiving cavity, and lower die punch), an extremely stable and reliable final forming environment is constructed. Using a special forming protrusion, high-efficiency, one-time, and high-quality cold forging of the plum blossom hole feature is achieved, resulting in superior mechanical properties and precision. The upper die punch of the fifth die extends into the upper forming cavity of the fifth die and is provided with a forming protrusion for plum blossom hole forming. That is, when the upper die punch reaches the deepest stroke point, the forming protrusion is located in the upper forming cavity of the fifth die. When the forming protrusion presses downward to form the plum blossom hole, the upper forming cavity of the fifth die provides a smooth guide for the material at the bottom of the groove to be pressed downward and transferred to the periphery, so that the billet extends axially.
[0023] The present invention further comprises: the depth of the three-mold receiving cavity is h3, the depth of the upper forming cavity of the five-mold is H5, 0.77h3≤H5≤0.85h3, the hole depth of the fifth blank is L5, wherein the depth of the upper groove of the fifth blank is L51 and the depth of the plum blossom hole is L52, L51=L4, 0.5L4≤L52≤0.55L4, and the height of the large diameter cylinder of the fifth blank is h5, 0.68h5≤L5≤0.79h5.
[0024] By adopting the above technical solution, with 0.77h3≤H5≤0.85h3, the working stroke of the five-upsetting forming protrusion is shorter than the length of the blank firmly held by the forming cavity of the five molds. This ensures that during the final forming impact, the rod of the blank always has sufficient length to be completely wrapped by the mold, ensuring absolute stability at the moment of forming the plum blossom hole, and improving the smoothness and efficiency of equipment operation. The four upsetting first forms a deeper upper groove, and the five upsetting then forms a shallower plum blossom hole, localizing and controlling the deformation area. The required forming force is moderate, which can ensure that the plum blossom hole teeth are full and the edges are clear, without defects caused by insufficient material filling or excessive extrusion.
[0025] The embodiments describe specific implementations of this utility model. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the step-by-step cold heading process of the blank in an embodiment of this utility model.
[0027] Figure 2 This is a cross-sectional view of the cold heading device according to an embodiment of the present invention.
[0028] Figure 3 This is a partial structural diagram of the lower die of an upsetting mold according to an embodiment of the present invention.
[0029] Figure 4 This is a partial structural schematic diagram of the two-stage upsetting mold according to an embodiment of the present invention.
[0030] Figure 5 This is a partial structural diagram of the three-upsetting mold according to an embodiment of the present utility model.
[0031] Figure 6 This is a partial structural schematic diagram of the four-upsetting mold according to an embodiment of the present utility model.
[0032] Figure 7 for Figure 2 Enlarged view of part A.
[0033] Reference numerals: 1. First upsetting die; 11. Lower die of first upsetting die; 111. Main mold cavity of first upsetting die; 1111. Upper forming cavity of first die; 1112. Lower forming cavity of first die; 1113. Transition cavity of first die; 112. Lower die punch of first die; 12. Upper die of first upsetting die; 121. Upper die punch of first die; 2. Second upsetting die; 21. Lower die of second upsetting die; 21 1. Main mold cavity of the second upsetting die; 2111. Upper forming cavity of the second die; 2112. Lower forming cavity of the second die; 212. Lower die punch of the second die; 2121. Lower conical protrusion; 22. Upper die of the second upsetting die; 221. Upper mold cavity of the second die; 2211. Upper mold cavity of the second die; 2212. Lower mold cavity of the second die; 222. Upper die punch of the second die; 2221. Upper conical protrusion; 3. Third upsetting die. Mold, 31. Lower mold of three-stage upsetting mold, 311. Main mold cavity of three-stage upsetting mold, 3111. Upper forming cavity of three-stage mold, 3112. Transition cavity of three-stage mold, 3113. Receiving cavity of three-stage mold, 312. Lower die punch of three-stage mold, 32. Upper mold of three-stage upsetting mold, 321. Upper die core of three-stage mold, 3211. Upper mold cavity of three-stage mold, 3212. Positioning protrusion; 4. Four-stage upsetting mold, 41 4. Lower die of the fourth upsetting die; 411. Main mold cavity of the fourth upsetting die; 4111. Upper forming cavity of the fourth die; 4112. Receiving cavity of the fourth die; 412. Lower die punch of the fourth die; 42. Upper die of the fourth upsetting die; 421. Upper die punch of the fourth die; 4211. Forming end; 5. Fifth upsetting die; 51. Lower die of the fifth upsetting die; 511. Main mold cavity of the fifth upsetting die; 5111. 5112. Fifth mold upper forming cavity; 512. Fifth mold receiving cavity; 52. Fifth mold lower die punch; 52. Fifth upsetting mold upper die; 521. Fifth mold upper die punch; 5211. Forming protrusion; 61. Initial blank; 62. First blank; 621. Small diameter rod; 622. Transition part; 63. Second blank; 631. Upper positioning recess; 632. Lower positioning recess; 633. Short truncated cone; 634. Long truncated cone; 64. Third blank; 641. Large diameter cylinder; 65. Fourth blank; 651. Upper groove; 66. Fifth blank; 661. Plum blossom hole. Detailed Implementation
[0034] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.
[0035] See appendix Figure 1-7This embodiment discloses a cold forging device for automotive chassis bearing bolts, including a cutting mechanism, an ejection mechanism, a transfer mechanism, and five molds. The cutting mechanism cuts the blank, the ejection mechanism lifts the blank, and the transfer mechanism moves and feeds the blank between the ejection mechanism and the five molds. The five molds include: a first forging mold 1 for initially shaping the initial blank 61 and extruding and stretching its lower end to form a small-diameter rod portion 621; a second forging mold 2 for initially flattening the upper section of the first blank 62 and forming positioning recesses at both the upper and lower ends of the first blank 62; and a third for forging the second blank 63... The upper section is further flattened to form a large-diameter cylinder 641 and the upper positioning recess 631 is deepened; the upper positioning recess 631 of the third blank 64 is deepened to form an upper groove 651 and the upper section of the third blank 64 is extruded and stretched; the upper positioning recess 631 of the fourth blank 65 is deepened to form a plum blossom hole 661 and the upper section of the fourth blank 65 is extruded and stretched. The five molds all include a lower mold and an upper mold. The lower mold includes a lower mold shell, a lower mold core and a lower mold punch. The lower mold core is located in the lower mold shell and has a main mold cavity.
[0036] This embodiment further includes the following configuration: the main mold cavity 111 of the upsetting mold includes an upper forming cavity 1111 for forming the upper section of the first blank 62 and a lower forming cavity 1112 for forming the lower section of the first blank 62. A transition cavity 1113, which is larger at the top and smaller at the bottom, is provided between the upper forming cavity 1111 and the lower forming cavity 1112. The transition cavity 1113 is used to form the transition portion 622 between the upper section of the second blank 63 and the small diameter rod portion 621. The upper end of the lower die punch 112 extends into the lower forming cavity 1112. The upper mold 12 of the upsetting mold includes an upper die punch 121, the lower end of which extends into the upper forming cavity 1111.
[0037] This embodiment further includes: the main mold cavity 211 of the second upsetting mold includes an upper mold forming cavity 2111 for further forming the transition portion 622 of the second blank 63 and a lower mold forming cavity 2112 for further forming the small-diameter rod portion 621 of the second blank 63 and forming a chamfer at its lower end. The upper mold forming cavity 2111 is flared, wider at the top and narrower at the bottom. The included angle of the inclined surface of the upper mold forming cavity 2111 is greater than the included angle of the inclined surface of the transition cavity 1113 of the first mold, and the depth of the upper mold forming cavity 2111 is less than the depth of the transition cavity 1113 of the first mold. The lower mold punch 212 is provided with a part at one end corresponding to the lower mold forming cavity 2112 to form the second blank 63. The lower end of the small-diameter rod portion 621 of the blank 63 forms a lower conical protrusion 2121 of the lower positioning recess 632; the upper mold 22 of the second upsetting mold includes a second mold upper mold core and a second mold upper mold punch 222. The second mold upper mold core includes a second mold upper mold cavity 221 for initially flattening the upper section of the first blank 62. The second mold upper mold punch 222 is provided with an upper conical protrusion 2221 at one end corresponding to the second mold upper mold cavity 221 for generating an upper positioning recess 631 at the top of the second blank 63. The diameter of the lower conical protrusion 2121 is smaller than the diameter of the upper conical protrusion 2221, and the depth of the second mold upper mold cavity 221 is smaller than the depth of the first mold upper forming cavity 1111.
[0038] This embodiment further includes the following configuration: the upper mold cavity 221 of the second mold includes an upper mold cavity 2211 for forming a short frustum 633 (smaller at the top and larger at the bottom) at the upper end of the upper section of the second blank 63, and a lower mold cavity 2212 for further shaping the upper section of the second blank 63 into a long frustum 634 (smaller at the top and larger at the bottom). The lower diameter of the upper mold cavity 2211 is adapted to the upper diameter of the lower mold cavity 2212. The upper diameter of the upper mold cavity 2211 is larger than the diameter of the upper molding cavity 1111 of the first mold. The depth of the upper mold cavity 2211 is 40%-70% of the depth of the lower mold cavity 2212. The included angle of the inclined surface of the upper mold cavity 2211 is larger than the included angle of the inclined surface of the lower mold cavity 2212.
[0039] This embodiment further specifies that: the upper outer periphery of the transition cavity 1113 of the first mold is arc-shaped; the included angle of the inclined surface of the transition cavity 1113 of the first mold is a1, 60°≤a1≤120°; the inner diameter of the upper forming cavity 1111 of the first mold is D1; the inner diameter of the lower forming cavity 1112 of the first mold is d1, 0.5D1≤d1≤0.8D1 (0.58D1≤d1≤0.7D1); the included angle of the inclined surface of the upper forming cavity 2111 of the second mold is a2, 120°≤a2≤160°; and the chamfer of the lower forming cavity 2112 of the second mold is a3, 30°≤a3≤50°. °; The depth of the upper mold cavity 221 of the second mold is H2, and the depth of the lower mold cavity 2112 of the second mold is h2, 0.9H2≤h2≤1.1H2; The maximum diameter of the upper mold cavity 2211 of the second mold is d2, 1.17D1≤d2≤1.26D1, and the depth of the upper mold cavity 2211 of the second mold is H21, 0.3H2≤H21≤0.4H2; The maximum diameter of the lower mold cavity 2212 of the second mold is D2, 1.26D1≤D2≤1.36D1, and the depth of the lower mold cavity 2212 of the second mold is H22, 0.6H2≤H22≤0.7H2.
[0040] In this utility model's technical solution, d1 is preferably 0.58D1≤d1≤0.7D1.
[0041] This embodiment further includes the following configuration: the main mold cavity 311 of the three-die mold includes a three-die upper forming cavity 3111 for further forming the upper section of the third blank 64 into a large-diameter cylinder 641, a three-die transition cavity 3112 for further forming the transition portion 622 of the third blank 64, and a three-die receiving cavity 3113 for accommodating the small-diameter rod portion 621 of the third blank 64; the depth of the three-die upper forming cavity 3111 is less than the depth of the two-die upper mold cavity 221, and the diameter of the three-die upper forming cavity 3111 is greater than the maximum diameter of the two-die upper mold cavity 221; the three-die transition cavity 3112 is cylindrical with a chamfered outer circumference at the lower end, and the diameter of the three-die transition cavity 3112 is... The diameter of the upper forming cavity 3111 of the three molds is adapted to the diameter of the upper forming cavity 3111 of the three molds; the upper forming cavity 3113 of the three molds is the same as the lower forming cavity 2112 of the two molds; the lower forming punch 312 of the three molds is the same as the lower forming punch 212 of the two molds; the upper mold 32 of the three-die mold includes an upper mold core 321 of the three molds, the upper mold core 321 of the three molds includes an upper mold cavity 3211 of the three molds for forming the upper section of the large-diameter cylinder 641, the upper mold cavity 3211 of the three molds is provided with a positioning protrusion 3212 for further deepening the upper positioning recess 631, the maximum diameter of the positioning protrusion 3212 is smaller than the diameter of the upper mold cavity 3211 of the three molds, and the upper outer periphery of the upper mold cavity 3211 of the three molds is provided with a chamfer.
[0042] This embodiment further includes the following configuration: the main mold cavity 411 of the four-die upsetting mold includes an upper forming cavity 4111 for extruding and stretching the large-diameter cylinder 641 of the fourth blank 65 and a receiving cavity 4112 for accommodating the small-diameter rod portion 621 of the fourth blank 65. The lower end of the upper forming cavity 4111 has the same shape as the transition cavity 3112 of the three-die. The receiving cavity 4112 has the same shape as the receiving cavity 3113 of the three-die. The lower die punch 412 of the four-die has the same structure as the lower die punch 212 of the two-die. The depth of the upper forming cavity 4111 of the four-die is greater than the depth of the upper forming cavity 3111 of the three-die. The upper die 42 of the four-die upsetting mold includes an upper die punch 421 of the four-die. One end of the upper die punch 421 extends into the upper forming cavity 4111 of the four-die and is provided with a forming end 4211 for deepening the upper positioning recess 631 of the fourth blank 65 into an upper groove 651.
[0043] This embodiment further specifies that: the inner diameter of the upper forming cavity 1111 of the first mold is D1, the inner diameter of the upper forming cavity 3111 of the third mold is D3, 1.25D1≤D3≤1.45D1, the depth of the upper receiving cavity 3113 of the third mold is h3, the depth of the upper forming cavity 3111 of the third mold is H3, 0.83h3≤H3≤0.92h3; the depth of the upper forming cavity 4111 of the fourth mold is H4, 0.99h3≤H4≤1.13h3, the depth of the upper groove 651 of the fourth blank 65 is L4, 1.63L4≤H4≤2.1L4, and the diameter of the forming end 4211 is D4, 0.67D3≤D4≤0.77D3.
[0044] In this utility model technical solution, D3 is preferably 1.3D1≤D3≤1.4D1, H3 is preferably 0.86h3≤H3≤0.89h3, H4 is preferably 1.03h3≤H4≤1.08h3, 1.65L4≤H4≤1.84L4, and D4 is preferably 0.67D3≤D4≤0.68D3.
[0045] This embodiment further includes the following configuration: the main mold cavity 511 of the five-die mold includes a five-die upper forming cavity 5111 for extruding and stretching the large-diameter cylinder 641 of the fifth blank 66 and a five-die receiving cavity 5112 for accommodating the small-diameter rod portion 621 of the fifth blank 66. The lower end of the five-die upper forming cavity 5111 has the same shape as the three-die transition cavity 3112. The five-die receiving cavity 5112 has the same shape as the three-die receiving cavity 3113. The five-die lower die punch 512 has the same structure as the two-die lower die punch 212. The depth of the five-die upper forming cavity 5111 is less than the depth of the four-die upper forming cavity 4111. The upper die 52 of the five-die mold includes a five-die upper die punch 521. One end of the five-die upper die punch 521, which extends into the five-die upper forming cavity 5111, is provided with a forming protrusion 5211 for forming the plum blossom hole 661.
[0046] This embodiment further specifies that: the depth of the three-mold receiving cavity 3113 is h3, the depth of the five-mold upper forming cavity 5111 is H5, 0.77h3≤H5≤0.85h3, the hole depth of the fifth blank 66 is L5, wherein the depth of the upper groove 651 of the fifth blank 66 is L51 and the depth of the plum blossom hole 661 is L52, L51=L4, 0.5L4≤L52≤0.55L4, and the height of the large diameter cylinder 641 of the fifth blank 66 is h5, 0.68h5≤L5≤0.79h5.
[0047] In the technical solution of this utility model, H5 is preferably 0.8h3≤H5≤0.83h3, L52 is preferably 0.52L4≤L52≤0.53L4, and L5 is preferably 0.75h5≤L5≤0.78h5.
[0048] The term "between" as used above does not only refer to the location or position, but also to the interaction between different parts. The terms "upper," "middle," and "lower" mentioned above are only relative positions for ease of explanation and do not exclude the possibility of using other terms.
[0049] The use of these terms is merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any kind of additional limitation would be contrary to the spirit of this utility model.
Claims
1. A cold forging device for automobile chassis bearing bolts, characterized in that: The assembly includes a cutting mechanism, an ejection mechanism, a transfer mechanism, and five molds. The cutting mechanism cuts the blank, and the ejection mechanism lifts the blank. The transfer mechanism moves and feeds material between the ejection mechanism and the five molds. The five molds include: a first upsetting mold for initially shaping the initial blank and extruding and stretching the lower end to form a small-diameter rod; a second upsetting mold for initially flattening the upper section of the first blank and forming positioning recesses at the upper and lower ends of the first blank; and a third upsetting mold for further shaping the upper section of the second blank. The three-stage upsetting mold is used to flatten the upper positioning recess of the third blank into a large-diameter cylinder and deepen the upper positioning recess; the four-stage upsetting mold is used to deepen the upper positioning recess of the third blank into an upper groove and to extrude and stretch the upper section of the third blank; the five-stage upsetting mold is used to deepen the bottom of the upper groove of the fourth blank into a plum blossom hole and to extrude and stretch the upper section of the fourth blank. Each of the five molds includes a lower mold and an upper mold. The lower mold includes a lower mold shell, a lower mold core and a lower mold punch. The lower mold core is located inside the lower mold shell and has a main mold cavity inside.
2. The cold heading device for automobile chassis bearing bolts according to claim 1, characterized in that: The main mold cavity of the upsetting die includes an upper forming cavity for forming the upper section of the first blank and a lower forming cavity for forming the lower section of the first blank. A transition cavity with a larger upper section and a smaller lower section is provided between the upper forming cavity and the lower forming cavity. The transition cavity is used to form the transition section between the upper section of the second blank and the small-diameter rod. The upsetting die includes a lower die punch, the upper end of which extends into the lower forming cavity. The upper die of the upsetting die includes an upper die punch, the lower end of which extends into the upper forming cavity.
3. The cold heading device for automobile chassis bearing bolts according to claim 2, characterized in that: The main mold cavity of the second upsetting die includes an upper forming cavity for further shaping the transition portion of the second blank and a lower forming cavity for further shaping the small-diameter rod portion of the second blank and forming a chamfer at its lower end. The upper forming cavity is flared, wider at the top and narrower at the bottom, with a greater slope angle than the transition cavity of the first die, and a shallower depth than the transition cavity of the first die. The second upsetting die includes a lower die punch, with one end of the lower die punch corresponding to the lower forming cavity of the second die. The upper die of the second upsetting die includes a lower conical protrusion that forms a lower positioning recess at the lower end of the small-diameter rod of the second blank; the upper die of the second upsetting die includes an upper die core and an upper die punch, the upper die core includes an upper die cavity for initially flattening the upper section of the first blank, the upper die punch has an upper conical protrusion at one end corresponding to the upper die cavity for forming an upper positioning recess at the top of the second blank, the diameter of the lower conical protrusion is smaller than the diameter of the upper conical protrusion, and the depth of the upper die cavity is smaller than the depth of the upper forming cavity of the first die.
4. The cold heading device for automobile chassis bearing bolts according to claim 3, characterized in that: The upper mold cavity of the second mold includes an upper mold cavity for forming a short frustum with a smaller top and a larger bottom at the upper end of the upper section of the second blank, and a lower mold cavity for further shaping the upper section of the second blank into a long frustum with a smaller top and a larger bottom. The lower end diameter of the upper mold cavity is adapted to the upper end diameter of the lower mold cavity. The upper end diameter of the upper mold cavity is larger than the diameter of the upper mold cavity of the first mold. The depth of the upper mold cavity is 40%-70% of the depth of the lower mold cavity. The included angle of the inclined surface of the upper mold cavity is larger than the included angle of the inclined surface of the lower mold cavity.
5. The cold heading device for automobile chassis bearing bolts according to claim 4, characterized in that: The upper outer periphery of the transition cavity of the first mold is arc-shaped, and the included angle of the inclined surface of the transition cavity of the first mold is a1, 60°≤a1≤120°. The inner diameter of the upper forming cavity of the first mold is D1, and the inner diameter of the lower forming cavity of the first mold is d1, 0.5D1≤d1≤0.8D1. The included angle of the inclined surface of the upper forming cavity of the second mold is a2, 120°≤a2≤160°. The chamfer of the lower forming cavity of the second mold is a3, 30°≤a3≤50°. The depth of the upper mold cavity of the second mold is... H2, the depth of the lower molding cavity of the second mold is h2, 0.9H2≤h2≤1.1H2; the maximum diameter of the upper cavity of the second mold is d2, 1.17D1≤d2≤1.26D1; the depth of the upper cavity of the second mold is H21, 0.3H2≤H21≤0.4H2; the maximum diameter of the lower cavity of the second mold is D2, 1.26D1≤D2≤1.36D1; the depth of the lower cavity of the second mold is H22, 0.6H2≤H22≤0.7H2.
6. The cold heading device for automobile chassis bearing bolts according to claim 3, characterized in that: The main mold cavity of the three-die forming mold includes an upper forming cavity for further shaping the upper section of the third blank into a large-diameter cylinder, a transition cavity for further shaping the transition portion of the third blank, and a receiving cavity for accommodating the small-diameter rod portion of the third blank. The depth of the upper forming cavity is less than the depth of the upper mold cavity, and the diameter of the upper forming cavity is greater than the maximum diameter of the upper mold cavity. The transition cavity is cylindrical with a chamfered outer circumference at the lower end, and its diameter is compatible with the diameter of the upper forming cavity. The three-die receiving cavity is the same as the lower forming cavity of the two-die; the three-die upsetting mold includes a lower die punch, which has the same structure as the lower die punch of the two-die; the upper die of the three-die upsetting mold includes an upper die core, which includes a cavity for forming the upper section of a large-diameter cylinder, and a positioning protrusion is provided in the cavity for further deepening the upper positioning recess. The maximum diameter of the positioning protrusion is smaller than the diameter of the upper die cavity, and a chamfer is provided on the outer periphery of the upper end of the upper die cavity.
7. The cold heading device for automobile chassis bearing bolts according to claim 6, characterized in that: The main mold cavity of the four-die upsetting die includes an upper forming cavity for extruding and stretching the large-diameter cylindrical part of the fourth blank and a receiving cavity for accommodating the small-diameter rod part of the fourth blank. The lower end of the upper forming cavity has the same shape as the transition cavity of the third die, and the receiving cavity has the same shape as the receiving cavity of the third die. The four-die upsetting die includes a lower die punch, which has the same structure as the lower die punch of the second die. The depth of the upper forming cavity is greater than that of the upper forming cavity of the third die. The upper die of the four-die upsetting die includes an upper die punch, and one end of the upper die punch that extends into the upper forming cavity has a forming end for deepening the upper positioning recess of the fourth blank into an upper groove.
8. The cold heading device for automobile chassis bearing bolts according to claim 7, characterized in that: The inner diameter of the forming cavity on the first mold is D1, the inner diameter of the forming cavity on the third mold is D3, 1.25D1≤D3≤1.45D1, the depth of the receiving cavity on the third mold is h3, the depth of the forming cavity on the third mold is H3, 0.83h3≤H3≤0.92h3; the depth of the forming cavity on the fourth mold is H4, 0.99h3≤H4≤1.13h3, the depth of the upper groove of the fourth blank is L4, 1.63L4≤H4≤2.1L4, and the diameter of the forming end is D4, 0.67D3≤D4≤0.77D3.
9. A cold heading device for automobile chassis bearing bolts according to claim 7, characterized in that: The main mold cavity of the five-die upsetting die includes an upper forming cavity for extruding and stretching the large-diameter cylindrical part of the fifth blank and a receiving cavity for accommodating the small-diameter rod part of the fifth blank. The lower end of the upper forming cavity has the same shape as the transition cavity of the third die, and the receiving cavity has the same shape as the receiving cavity of the third die. The five-die upsetting die includes a lower die punch, which has the same structure as the lower die punch of the second die. The depth of the upper forming cavity is less than that of the upper forming cavity of the fourth die. The upper die of the five-die upsetting die includes an upper die punch, and one end of the upper die punch that extends into the upper forming cavity has a forming protrusion for forming a perforated hole.
10. A cold heading device for automobile chassis bearing bolts according to claim 9, characterized in that: The depth of the cavity in the three molds is h3, the depth of the upper forming cavity in the fifth mold is H5, 0.77h3≤H5≤0.85h3, the hole depth of the fifth blank is L5, wherein the depth of the upper groove of the fifth blank is L51 and the depth of the plum blossom hole is L52, L51=L4, 0.5L4≤L52≤0.55L4, and the height of the large diameter cylinder of the fifth blank is h5, 0.68h5≤L5≤0.79h5.