Integral worm forge piece for new energy vehicle and forming die of worm forge piece
Through the hot forging and cold forging forming process and annealing treatment of the integral worm forging, the problem of mechanical property differences at the weld in the split welding structure is solved, and the high strength and efficient production of the worm shaft is achieved.
Patent Information
- Application Number
- CN202421750709.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-23
- Publication Date
- 2025-09-12
- Estimated Expiration
- 2034-07-23
AI Technical Summary
The split welding structure of the existing worm shaft of new energy vehicles leads to differences in mechanical properties and uneven structure at the weld, affecting the life and stability of the worm shaft.
The integral worm forging design is adopted. Through hot forging and cold forging forming process, combined with annealing treatment, a coherent metal streamline structure is formed. The keyway of the head is connected with the rod as a whole, and a special forming die is used for processing.
The torsional strength and tensile strength of the worm shaft are improved, welding defects are reduced, material utilization and production efficiency are improved, and energy consumption is reduced.
Smart Images
Figure CN223331083U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of automobile parts and specifically relates to an integral worm gear for new energy vehicles.
[0002] Forming dies for forgings and worm forgings. Background Art
[0003] With the continuous development of modern industry, environmental issues are becoming increasingly prominent. The renewed focus on development strategies in the domestic and international automotive markets and the growing acceptance of energy-saving and environmentally friendly concepts are driving the increasing acceptance of new energy vehicles. Most new energy vehicles utilize electric power, and their transmission structures prioritize longevity and stability. Existing worm shafts in new energy vehicles are typically split-welded structures. Furthermore, automotive worm shafts are subject to significant torque and impact loads during use. The strength differences between the weld and the material at the joint of the split-welded worm structure, as well as structural differences, directly impact the service life of the new energy vehicle reducer. With increasing safety requirements for new energy vehicles, and in line with market demand, the existing worm shafts in new energy vehicles need to be upgraded to a single-piece structure. Utility Model Content
[0004] In order to overcome the above shortcomings, the utility model provides an integral new energy vehicle worm forging and worm
[0005] The forming die of the rod forging solves, to a certain extent, the technical problems existing in the prior art, such as the difference in mechanical properties and uneven structure at the weld of the split-welded structure worm.
[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:
[0007] A one-piece worm forging for new energy vehicles comprises a head notch and a rod portion connected in sequence. The rod portion initially has the grain structure of the original billet, which is then recrystallized and refined after annealing heat treatment. The head notch structure is an elongated cold forged structure, and its initial internal structure is the grain structure of hot forging. After annealing treatment, the grains are recrystallized and refined, and a head keyway structure is formed by cold forging and reverse extrusion.
[0008] Further optimization is performed, wherein the head notch and the rod portion are an integrated structure.
[0009] A forming die for an integral worm forging for new energy vehicles comprises a hot forging forming device and a cold forging forming device. The hot forging forming device is used to hot forge a cylindrical blank, and the cold forging forming device is used to cold forge an intermediate blank.
[0010] Further optimization, the hot forging forming device includes a hot forging lower die, a hot forging push rod, a hot forging die and a hot forging punch. The hot forging die and the hot forging lower die are positioned by a concave and convex stop structure. The hot forging push rod is located in the through hole of the hot forging lower die, and the hot forging punch is arranged on the upper moving mechanism of the stamping machine.
[0011] Further optimized, the cold forging forming device includes a cold extrusion ejector pin, a cold extrusion pad, a lower die core, a lower die outer sleeve, an upper die outer sleeve, an upper die middle ring, an upper die core, a punch outer sleeve, a punch core and a cold extrusion punch.
[0012] Further optimization, the cold extrusion punch is arranged on the upper moving mechanism of the press, which is installed in the mounting stepped through hole of the punch core, the punch core is installed inside the punch sleeve, the punch sleeve and the punch core are positioned by a concave and convex stop structure, the upper die center ring is installed in the tapered hole of the upper die sleeve, the upper die core is installed in the tapered hole of the upper die center ring, and the lower die core is installed in the tapered hole of the lower die sleeve; the cold extrusion ejector pin is located in the mounting through hole of the cold extrusion pad.
[0013] Further optimization is carried out, the tapered holes between the upper mold core and the upper mold middle ring, the tapered holes between the upper mold middle ring and the upper mold outer sleeve, and the tapered holes between the lower mold core and the lower mold outer sleeve are interference fit, and the interference amount is 4 / 1000 to 8 / 1000 of the fitting diameter.
[0014] Further optimization is carried out, the lower mold sleeve is positioned with the upper mold sleeve through concave and convex stopper structures to ensure that the internal mold holes are concentric.
[0015] Further optimization is carried out, and the cross-sectional dimensions of the small end key of the cold extrusion punch are such that the ligament contour is offset inward by 0.15 mm, and the ligament L0 is 4 mm wide.
[0016] The beneficial effects of the utility model are:
[0017] The worm shaft forging is formed with a continuous metal streamline extending from its head keyway toward its lower end rod. The tensile strength along the streamline direction is high, and the integral connection between the head keyway and the rod improves the torsional strength of the worm shaft forging. The worm shaft forging prepared by the forming mold has less flash and high material utilization. Compared with the existing split welding process, the utility model adopts one-piece forming, which effectively avoids defects such as pores, slag inclusions, incomplete welding and undercutting in the welding parts. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 A schematic structural diagram of a worm shaft forging provided in an embodiment of the present application;
[0019] Figure 2 A schematic diagram of the metal streamline distribution of the worm shaft forging provided in an embodiment of the present application;
[0020] Figure 3 A schematic diagram of the cold and hot forging composite forming process of the worm shaft forging provided in an embodiment of the present application;
[0021] Figure 4 A schematic structural diagram of a hot forging device provided in an embodiment of the present application;
[0022] Figure 5 A schematic structural diagram of a cold forging device provided in an embodiment of the present application;
[0023] Figure 6 A schematic diagram of the cold extrusion punch structure provided in an embodiment of the present application;
[0024] Figure 7 A schematic diagram of the annealing process provided in the embodiment of the present application;
[0025] 1. Hot forging lower die, 2. Hot forging ejector pin, 3. Hot forging concave die, 4. Hot forging punch, 5. Cylindrical blank, 6. Cold extruded ejector pin, 7. Cold extruded spacer, 8. Lower die core, 9. Lower die outer shell, 10. Upper die outer shell, 11. Upper die center ring, 12. Upper die core, 13. Punch outer shell, 14. Punch core, 15. Cold extruded punch, 16. Intermediate blank, 15-1. Punch small end, 15-2. Punch large end, 17. Worm shaft forging, 17-1. Head keyway, 17-2. Rod. DETAILED DESCRIPTION
[0026] In order to more clearly understand the above-mentioned purposes, features and advantages of the present invention, the present invention is described in detail below in conjunction with specific embodiments. The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the following embodiments.
[0027] A one-piece worm forging for new energy vehicles, wherein the worm shaft forging 17 is formed with a continuous metal streamline extending from its head keyway toward its lower end rod, and the metal streamline extends vertically along the contour of the worm shaft forging 17; the worm shaft forging 17 includes a head keyway 17-1 and a rod 17-2 connected in sequence, wherein the structure of the rod 17-2 is initially the grain structure of the original billet, and is then recrystallized and refined after annealing heat treatment; the initial structure of the head 17-1 is the grain structure of hot forging, and after annealing treatment, the grains are recrystallized and refined, and after the plasticity is improved, it is cold forged and back-extruded into an elongated grain structure.
[0028] The worm shaft forging 17 features continuous metal streamlines extending from its head keyway toward its lower shank. This provides high tensile strength along these streamlines, and the integral connection between the head keyway 17-1 and the shank 17-2 enhances the worm shaft forging's torsional strength. Utilizing these features during production, ensuring a continuous distribution of streamlines within the worm shaft forging, aligned with the direction of force applied, and ensuring a monolithic structure across all worm shaft components, significantly improves the worm shaft forging's load-bearing capacity. Conversely, significant streamline defects, such as turbulent flow or through-flow, can compromise the tensile strength of the worm shaft forging 17. Separately welding the worm shaft head keyway and shank can lead to defects such as porosity, slag inclusions, incomplete penetration, and undercutting. Furthermore, subsequent processing can result in faulty streamlines at the weld, compromising the torsional and tensile strength of the worm shaft forging 17.
[0029] A forming method of an integral worm forging 17 for new energy vehicles, the forming method specifically comprising the following steps:
[0030] Step 1: After heating one end of the cylindrical blank 5 to 1050° C., hot forging is performed to obtain an intermediate blank 16. The cylindrical blank is prepared by using a rolled metal profile as a raw material and cutting the material in equal volume according to the volume required for the final product to form a cylindrical blank 5 of a predetermined size.
[0031] Step 2: The intermediate blank 16 after hot forging is annealed to refine the grains, reduce deformation resistance, and improve plasticity. It is then subjected to roller burnishing to remove surface oxide scale and finally lubricated.
[0032] The annealing heat treatment process is as follows: first, the intermediate billet 16 is placed in a heating furnace, and the temperature is rapidly raised to 935°C over 1 hour, then kept at 935°C for 18 hours, and then rapidly cooled to 780°C over 1 hour, and kept at this temperature for 22 hours before being taken out;
[0033] Step 3: Perform local cold reverse extrusion on the head of the heat-treated intermediate blank 16 to form a keyway 17 - 1 structure on the head, thereby obtaining a worm shaft forging 17 .
[0034] The worm shaft forging 17 produced by the aforementioned processing method exhibits a microstructure of the shank portion 17-2 characterized by a recrystallized, refined structure after heat treatment, while the head portion 17-1 exhibits an elongated, cold-forged grain structure. Furthermore, the forging exhibits a residual effect of the heat-treated microstructure, preserving both the longitudinal streamlines formed during the original rolling of the cylindrical bar and the reversed longitudinal streamlines formed during cold forging. This ensures a vertically coherent distribution of streamlines throughout the forging. These continuous streamlines provide high tensile strength along the streamline direction (longitudinal direction), significantly enhancing the load-bearing capacity of the screw forging 17.
[0035] In addition, the worm shaft forging 17 produced by the method is substantially free of burrs, does not require extensive cutting, and has a high material utilization rate. Furthermore, the overall simplified process steps also result in higher production efficiency and lower energy consumption.
[0036] The worm shaft forging 17 is formed by a forming die. The forming die of the worm shaft forging 17 includes a hot forging forming device and a cold forging forming device. The hot forging forming device is used to hot forge the cylindrical blank 5, and the cold forging forming device is used to cold forge the intermediate blank 17.
[0037] The hot forging forming device includes a hot forging lower die 1, a hot forging push rod 2, a hot forging die 3 and a hot forging punch 4; wherein, the hot forging die 3 and the hot forging lower die 1 are positioned by a concave and convex stop structure, the hot forging push rod 2 is located in the through hole of the hot forging lower die 1, and the hot forging punch 4 is arranged on the upper moving mechanism of the stamping machine.
[0038] Based on the above structure, it can be known that during use, the cylindrical blank 5 can be placed in the die cavity, and then punched by the hot forging punch 4 to form the intermediate blank 17 through positive extrusion.
[0039] The cold forging forming device includes a cold extrusion ejector pin 6, a cold extrusion pad 7, a lower die core 8, a lower die jacket 9, an upper die jacket 10, an upper die center ring 11, an upper die core 12, a punch jacket 13, a punch core 14, and a cold extrusion punch 15. Furthermore, in the above technical solution, the cold extrusion punch 15 is arranged on the upper moving mechanism of the press, and is installed in the mounting step through hole of the punch core 14; the punch core 14 is installed inside the punch jacket 13, and is positioned with each other through a concave and convex stopper structure; the upper die center ring 11 is installed in the tapered hole of the upper die jacket 10, and the upper die core 12 is installed in the tapered hole of the upper die center ring 11; the lower die core 8 is installed in the tapered hole of the lower die jacket 9; and the cold extrusion ejector pin 6 is located in the mounting through hole of the cold extrusion pad 7.
[0040] The upper mold core 12 and the tapered hole of the upper mold center ring 11, the upper mold center ring 11 and the tapered hole of the upper mold outer shell 10, and the lower mold core 8 and the tapered hole of the lower mold outer shell 9 form an interference fit, with the interference being 0.4 to 0.8 thousandths of the mating diameter. This interference fit ensures a tight fit between adjacent structures, generating a preload toward the interior of the mold cavity, thereby offsetting the expansion force from the outside of the mold cavity during screw molding, protecting the molding device and extending its service life.
[0041] The lower mold sleeve 9 is positioned with the upper mold sleeve 10 through concave and convex stopper structures to ensure that the internal mold holes are concentric.
[0042] In addition, the upper mold core 12 and the lower mold core 8 are designed as a split structure, which is convenient for processing and installation, and also convenient for repairing or replacing the worn or failed parts of the mold during subsequent use, saving mold costs.
[0043] The key-shaped cross-sectional dimensions of the small end 15-1 of the cold extrusion punch are such that the ligament contour is offset inward by 0.15 mm, and the ligament L0 is 4 mm wide.
[0044] The above shows and describes the main features, methods of use, basic principles, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and improvements may be made to the present invention based on actual circumstances without departing from the spirit and scope of the present invention. Such changes and improvements are intended to fall within the scope of the present invention. The scope of protection claimed in this invention is defined by the appended claims and their equivalents.
Claims
1. An integral worm forging for new energy vehicles, characterized in that: The invention comprises a head keyway (17-1) and a rod (17-2) connected in sequence, wherein the rod (17-2) initially has the grain structure of the original billet, which is then recrystallized and refined after annealing heat treatment; the head keyway (17-1) has an elongated cold forging structure, and its initial internal structure is a hot forging grain structure, which is recrystallized and refined after annealing treatment, and the head keyway structure is generated by cold forging and reverse extrusion.
2. The integral worm forging for new energy vehicles according to claim 1, characterized in that: The head keyway (17-1) and the rod portion (17-2) are an integrated structure.
3. A forming die for preparing an integral worm forging for new energy vehicles as claimed in claim 1 or 2, characterized in that: It comprises a hot forging forming device and a cold forging forming device, wherein the hot forging forming device is used to perform hot forging treatment on a cylindrical blank (5), and the cold forging forming device is used to perform cold forging treatment on an intermediate blank (17).
4. A forming die for preparing the integral worm forging for new energy vehicles as claimed in claim 1 or 2 according to claim 3, characterized in that: The hot forging forming device comprises a hot forging lower die (1), a hot forging ejector pin (2), a hot forging concave die (3) and a hot forging punch (4); the hot forging concave die (3) and the hot forging lower die (1) are positioned via a concave-convex stopper structure; the hot forging ejector pin (2) is located in a through hole of the hot forging lower die (1); and the hot forging punch (4) is arranged on an upper moving mechanism of a punching machine.
5. A forming die for preparing the integral worm forging for new energy vehicles as claimed in claim 1 or 2 according to claim 3, characterized in that: The cold forging device comprises a cold extrusion ejector pin (6), a cold extrusion pad (7), a lower die core (8), a lower die outer sleeve (9), an upper die outer sleeve (10), an upper die center ring (11), an upper die core (12), a punch outer sleeve (13), a punch core (14), and a cold extrusion punch (15).
6. A forming die for preparing the integral worm forging for new energy vehicles as claimed in claim 1 or 2 according to claim 5, characterized in that: The cold extrusion punch (15) is arranged on the upper moving mechanism of the press, and is installed in the mounting stepped through hole of the punch core (14). The punch core (14) is installed inside the punch jacket (13). The punch jacket (13) and the punch core (14) are positioned by a concave-convex stopper structure. The upper die center ring (11) is installed in the tapered hole of the upper die jacket (10). The upper die core (12) is installed in the tapered hole of the upper die center ring (11). The lower die core (8) is installed in the tapered hole of the lower die jacket (9); the cold extrusion ejector pin (6) is located in the mounting through hole of the cold extrusion pad (7).
7. A forming die for preparing the integral worm forging for new energy vehicles as claimed in claim 1 or 2 according to claim 5, characterized in that: The tapered holes of the upper mold core (12) and the upper mold center ring (11), the tapered holes of the upper mold center ring (11) and the upper mold outer sleeve (10), and the tapered holes of the lower mold core (8) and the lower mold outer sleeve (9) are interference fits, and the interference amount is 0.4 to 0.8 of the matching diameter.
8. A forming die for preparing the integral worm forging for new energy vehicles as claimed in claim 1 or 2 according to claim 5, characterized in that: The lower mold outer sleeve (9) is positioned with the upper mold outer sleeve (10) through concave and convex stopper structures to ensure that the internal mold holes are concentric.
9. A forming die for preparing the integral worm forging for new energy vehicles as claimed in claim 1 or 2 according to claim 5, characterized in that: The key-shaped cross-sectional dimensions of the small end (15-1) of the cold extrusion punch are such that the ligament profile is offset inward by 0.15 mm, and the ligament L0 is 4 mm wide.