Tool for die forging of planet row shell press
By designing the flare-free groove structure and ion nitriding treatment of the planetary shell press die-forging tooling, the problems of poor mold interchangeability and inconvenience in loading and unloading in forgings are solved, and efficient production and low-cost forging manufacturing are achieved.
Patent Information
- Application Number
- CN202422035794.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-21
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-08-21
AI Technical Summary
In the prior art, the microstructure and mechanical properties of forgings are low, the machining allowance is large, the processing efficiency is low, the material utilization rate is low, the manufacturing cost is high, the mold interchangeability is not strong, and the mold loading and unloading is inconvenient, resulting in low production efficiency and high cost of forgings.
A planetary shell press die-forging tool is designed, using a flash-free groove structure of upper forging die and lower forging die, combined with 5CrNiMo material and ion nitriding treatment to ensure the strength and shape of the mold, and the rapid mold change is achieved through the cooperation of the press ring and the positioning pad, reducing maintenance costs and improving service life.
It realizes efficient production of parts below the limit size, reduces mold manufacturing and maintenance costs, improves mold service life and production efficiency, and ensures the quality and accuracy of forgings.
Smart Images
Figure CN223234981U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of hot forging tooling, in particular to a tooling for die forging of a planetary gear housing press. Background Art
[0002] The automotive industry boasts a high degree of die forging. For example, automotive planetary gears, sun gears, and differentials are all produced using precision die forging, placing it at the forefront of domestic forging applications. Some companies in the weapons and aerospace industries also use precision die forging technology to produce forging blanks, achieving good economic returns. However, these companies are generally smaller than the automotive industry, primarily due to objective factors such as product diversity, small batch sizes, high die production costs, limited die interchangeability, and inconvenient die assembly and disassembly, which restrict the application of forgings in presses. Therefore, free forging or conventional die forging technology is typically used during the manufacturing process. The microstructure and mechanical properties of forgings are inferior to those of precision die forgings, and machining allowances are large, resulting in low processing efficiency, low material utilization, high manufacturing costs, and poor product surface quality.
[0003] With the development requirements of lean production and green manufacturing, precision die forging technology has been developed. In addition to the tonnage limitation of the equipment itself, the mold cost and traditional mold design methods make only forgings of a small range of sizes suitable for a certain equipment. Equipment investment also restricts the development of precision die forging technology. Summary of the Invention
[0004] In order to solve the above technical problems, the utility model provides a tooling for planetary gear housing press forging that can be used to produce all parts below the limit size of forging equipment, and has good control over mold manufacturing costs. At the same time, it is easy to load and unload, has low maintenance costs, long service life and good interchangeability.
[0005] The technical solution adopted by the utility model is: a tooling for die forging of a planetary gear housing press, comprising an upper forging die, a lower forging die and a lower forging die ejector rod; an upper forging die pressing die ring is provided on the upper forging die; a lower forging die pressing die ring is provided on the lower forging die; the upper forging die cooperates with the lower forging die to form a cavity, a through hole is provided on the lower forging die at the bottom of the cavity, and a lower forging die ejector rod is provided in the through hole.
[0006] Furthermore, the upper forging die and the lower forging die are cylindrical and adopt a flashless groove structure. The upper forging die is fixed to the pressure head of the press through the upper forging die ring; the lower forging die is fixed to the workbench of the press through the lower forging die ring; an upper forging die positioning plate is provided between the upper forging die and the pressure head, and a lower forging die positioning plate is provided between the lower forging die and the workbench.
[0007] Furthermore, the upper forging die positioning pad and the lower forging die positioning pad are both cylindrical with a circular groove on one end surface.
[0008] Furthermore, the press adopts an EP-1600 electric screw press; the outer diameter of the upper forging die positioning plate is Φ259mm, the positioning groove size is Φ220mm, and the outer diameter of the top of the upper forging die is Φ219.5mm; the outer diameter of the lower forging die positioning plate is Φ359mm, the positioning groove size is Φ260mm, and the outer diameter of the bottom of the lower forging die is Φ259.5mm. The die height of the upper forging die and the lower forging die is 400mm.
[0009] Furthermore, the upper forging die ring and the lower forging die ring are annular, and the upper forging die ring cooperates with the upper forging die, with a matching size of Φ262mm; the lower forging die ring cooperates with the lower forging die, with a matching size of Φ322mm.
[0010] Furthermore, the material used for the upper forging die and the lower forging die is 5CrNiMo with a hardness of 42~48 HRC; the upper forging die and the lower forging die are ion nitrided, and the hardened layer depth of the working surface of the upper forging die and the lower forging die is 0.5~0.7mm, and the hardness is ≥600HV; the cavity surface is finely polished, and the roughness of the cavity surface is ≤Ra0.8, and the roughness of the other surfaces is ≤Ra6.3.
[0011] Furthermore, the lower forging die ejector pin is located at the center of the lower forging die, and the material used is 5CrNiMo with a hardness of 40~45HRC; the lower forging die ejector pin is ion nitrided, and the hardened layer depth of the working surface of the lower forging die ejector pin is 0.5~0.7mm, and the hardness is ≥600HV. The roughness of the part of the cavity surface constituted by the lower forging die ejector pin is ≤Ra0.8, and the roughness of the remaining surface is ≤Ra6.3.
[0012] Furthermore, the sharp corners of the upper forging die, the lower forging die ejector pin and the lower forging die are all rounded R1 to R2.
[0013] Compared with the prior art, the beneficial effects of the present invention are:
[0014] 1. The utility model has a simple structure, is easy to assemble and disassemble, and has low maintenance cost.
[0015] 2. The upper and lower forging dies of this utility model adopt a flashless groove structure, which reduces the raw materials required for forgings. Positioning and guiding are achieved through the die ring. The die rings of the upper and lower forging dies are annular, and their inner diameters match those of the upper and lower forging dies. This makes manufacturing simple, positioning and guiding accurate, and easy to adjust the dies. Die misalignment is not likely to occur, which helps control the generation of longitudinal burrs, improve the quality of forgings, and extend the service life of the dies.
[0016] 3. The upper and lower forging dies of this utility model are made of 5CrNiMo with a hardness of 42-48 HRC. After ion nitriding, the working surface hardened layer is 0.5-0.7mm deep and has a hardness of ≥600HV, ensuring mold strength and shape. The cavity surface is finely polished to a roughness of ≤Ra0.8, and the remaining surfaces are ≤Ra6.3, extending mold life and reducing mold replacement costs.
[0017] 4. The lower forging die of this utility model is made of 5CrNiMo with a hardness of 40-45 HRC. After ion nitriding, the working surface hardened layer is 0.5-0.7mm deep and has a hardness of ≥600HV, ensuring mold strength and shape. The cavity surface is finely polished to a roughness of ≤Ra0.8, and the remaining surfaces are ≤Ra6.3, extending mold life and reducing mold replacement costs.
[0018] 5. The sharp corners of the upper forging die, the lower forging die ejector pin and the lower forging die of the utility model are all rounded R1~R2, which can prevent the lower forging die ejector pin from causing product folding defects during production, or prevent the forging from being damaged by the ejector pin when the product is ejected by the ejector pin, thereby improving the quality of the forging and reducing the risk of forging scrap.
[0019] 7. The upper forging die and the lower forging die of the utility model are positioned by a pad, a die ring and fastening bolts. When replacing the die, it is only necessary to remove the bolts when closing the die. After the slider on the press returns to its position, the upper forging die can be replaced. The lower forging die can be easily taken out and replaced by removing the die ring of the lower forging die. It can realize fast die change and production change, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a cross-sectional view of the present utility model.
[0021] Figure 2 It is a structural schematic diagram of the upper forging die of the present utility model.
[0022] Figure 3 It is a cross-sectional view of the upper forging die ring of the utility model;
[0023] Figure 4 It is a cross-sectional view of the lower forging die of the utility model;
[0024] Figure 5 It is a cross-sectional view of the lower forging die ring of the utility model.
[0025] Figure 6 It is a cross-sectional view of the positioning pad of the lower forging die of the present invention.
[0026] Figure 7 This is a schematic structural diagram of the lower forging die ejector rod of the utility model;
[0027] Figure 8It is a cross-sectional view of the upper forging die positioning pad of the present utility model.
[0028] Figure 1 Middle: 1. Upper forging die; 2. Upper forging die ring; 3. Lower forging die; 4. Lower forging die ring; 5. Lower forging die positioning plate; 6. Fastening bolts; 7. Lower forging die ejector rod; 8. Planetary gear housing; 9. Upper forging die positioning plate. DETAILED DESCRIPTION
[0029] The present invention is described in detail below with reference to the accompanying drawings.
[0030] like Figures 1-8 As shown, the utility model includes an upper forging die 1, a lower forging die 3 and a lower forging die ejector rod 7; an upper forging die ring 2 is provided on the upper forging die 1; a lower forging die ring 4 is provided on the lower forging die 3; the upper forging die 1 and the lower forging die 3 cooperate to form a cavity, and a through hole is provided on the lower forging die 3 at the bottom of the cavity, and a lower forging die ejector rod 7 is provided in the through hole. The upper forging die 1 and the lower forging die 3 are cylindrical and adopt a flashless groove structure. The upper forging die ring 2 is fixed to the ram of the press by multiple bolts 6; the lower forging die ring 4 is fixed to the workbench of the press by multiple bolts 6. The press adopts an EP-1600 electric screw press. An upper forging die positioning plate 9 is provided between the upper forging die 1 and the ram, and a lower forging die positioning plate 5 is provided between the lower forging die 3 and the workbench. The upper forging die positioning plate 9 and the lower forging die positioning plate 5 are both cylindrical with a circular groove on one end face; the circular grooves of the upper forging die positioning plate 9 and the lower forging die positioning plate 5 face the upper forging die and the lower forging die respectively.
[0031] The upper forging die positioning plate 9 has an outer diameter of Φ259mm and a positioning groove of Φ220mm. The top outer diameter of the upper forging die 1 is Φ219.5mm. The lower forging die positioning plate 5 has an outer diameter of Φ359mm and a positioning groove of Φ260mm. The bottom outer diameter of the lower forging die 3 is Φ259.5mm. The minimum die height of this equipment is 800mm. For ease of assembly, the upper and lower forging dies 1 and 3 are closed at a height of 400mm.
[0032] The upper forging die ring 2 and the lower forging die ring 4 are annular in shape. The upper forging die ring 2 and the upper forging die 1 have a mating dimension of 262 mm, while the lower forging die ring 4 and the lower forging die 3 have a mating dimension of 322 mm. This ensures accurate positioning and guidance, convenient die adjustment, and a low risk of die misalignment. This helps control the generation of longitudinal burrs, improves the quality of forgings, and increases their service life.
[0033] The upper forging die 1 and the lower forging die 3 are made of 5CrNiMo. To eliminate residual stress in the mold and improve microstructure uniformity, they require normalizing, quenching, and secondary tempering. During quenching, they are preheated at 600°C for 2 hours, then slowly heated to 850°C over 3 hours, held at that temperature for 3 hours, and then oil-cooled. Secondary tempering is performed at 300°C for 8 hours, after the initial tempering at 510°C for 5 hours has completely cooled. The hardness of the upper forging die 1 and the lower forging die 3 is 42-48 HRC. The cavity surfaces of the upper forging die 1 and the lower forging die 3 are finely polished to a roughness of ≤Ra0.8, and the roughness of the remaining surfaces is ≤Ra6.3. This increases service life and reduces replacement costs.
[0034] The material of the upper forging die 1 and the lower forging die 3 is 5CrNiMo. In order to ensure the toughness of the die and improve the hardness of the die working surface, it is necessary to perform ion nitriding after tempering (quenching and secondary tempering). Before ion nitriding, the die working surface should be clean and free of oil stains and scratches. The nitriding process parameters are 490~500℃, the hardened layer depth is 0.5~0.7mm, and after 4h of denitrification, the hardness of the working surface of the upper forging die 1 and the lower forging die 3 is ≥600HV.
[0035] The upper forging die 1 and the lower forging die 3 are fixed in size and are of standardized design. For forgings of different sizes below a certain diameter, it is only necessary to replace the upper forging die 1, the lower forging die 3 and the lower forging die ejector rod 7. For forgings of sizes above a certain diameter, it is only necessary to remove the upper forging die positioning plate 9 and the lower forging die positioning plate 5 and directly replace the upper forging die 1, the lower forging die 3 and the lower forging die ejector rod 7 to put them into production. It has strong versatility and can greatly save the manufacturing and maintenance costs of the mold.
[0036] The lower forging die ejector pin 7 is made of 5CrNiMo. To eliminate residual stress in the die and improve microstructure uniformity, it requires normalizing, quenching, and secondary tempering. During quenching, the die is preheated at 600°C for 2 hours, then slowly heated to 850°C over 3 hours, held at that temperature for 3 hours, and then oil-cooled. Secondary tempering is performed at 300°C for 8 hours, requiring complete cooling after the initial tempering at 490°C for 5 hours. To prevent damage to the die, the lower forging die ejector pin 7 has a slightly lower hardness of 40-45 HRC. The cavity surface is finely polished to a roughness of ≤Ra0.8 for the portion that forms the cavity surface, and ≤Ra6.3 for the remaining surface. This increases service life and reduces replacement costs.
[0037] The material of the lower forging die ejector pin 7 is 5CrNiMo. In order to ensure the hardness of the contact surface of the ejector pin, it needs to be tempered, quenched and tempered twice before ion nitriding. The working surface of the mold should be clean before ion nitriding, and no oil stains or scratches are allowed. The nitriding process parameters are 490~500℃, the hardened layer depth is 0.5~0.7mm, and after 4h of denitrification, the contact surface hardness of the lower forging die ejector pin 7 is ≥600HV.
[0038] The sharp corners of the upper forging die 1, the lower forging die ejector pin 7 and the lower forging die 3 all need to be rounded R1 to R2. The surface of the lower forging die ejector pin adopts a stepped arc transition with an arc angle of R10. This can prevent the lower forging die ejector pin 7 from causing product folding defects during production, or the forgings from being damaged by the ejector pin when the product is ejected by the ejector pin, thereby improving the forging quality and reducing the risk of forging scrap;
[0039] The upper forging die 1 and the lower forging die 3 are positioned by a pad, a die ring and fastening bolts. When changing the die, it is only necessary to remove the bolts when closing the die. After the slider on the press returns to its position, the upper forging die 1 can be replaced. The lower forging die 3 can be easily taken out and replaced by removing the die ring 4 of the lower forging die, which can realize fast die change and production change, thereby improving production efficiency.
[0040] A planetary gear housing press die forging method, comprising the following processing steps:
[0041] Process implementation: heating, blank making, die forging
[0042] The billets for production are heated in a natural gas furnace at approximately 1150°C for 60-90 minutes, with 30 pieces per batch. After heating, the billets are removed from the furnace, formed on a forging hammer, and descaled in preparation for die forging. The prepared billets are placed in the cavity of the lower forging die 3, adjusted, and the press is started. The slide moves the upper forging die 1 downward, and after the die is closed, the slide returns to its original position, completing the forging process. After the forging is formed, the hydraulic ejector switch is activated, and the hydraulic cylinder drives the lower forging die ejector rod 7 to eject the forging from the cavity of the lower forging die 3, eliminating the need for trimming.
[0043] The specific principle of the present utility model is as follows: before forging the raw materials, the tooling of the present invention is first installed on the screw press, and the die ring, pads, and fastening bolts help to fix the tooling. The upper forging die 1, the lower forging die 3 and the lower forging die ejector rod 7 are kept on the same axis, the module height is adjusted, the raw materials are placed in the die cavity of the lower forging die 3 after being blanked, the press is started, the slider drives the upper forging die 1 to move downward, and the slider is reset after the mold is closed. The hydraulic ejection switch is started, and the hydraulic cylinder drives the lower forging die ejector rod 7 to eject the forging out of the die cavity of the lower forging die 3, completing a one-time forging process.
[0044] When using this utility model, the operation is as follows:
[0045] 1) Install the utility model on a screw press;
[0046] 2) Adjust the distance between the upper forging die 1 and the lower forging die 3 so that the upper forging die 1, the lower forging die 3 and the lower forging die ejector rod 7 are aligned on the same axis;
[0047] 3) After the raw material is formed into a blank, it is placed in the cavity of the lower forging die 3. The press is started, and the slider drives the upper forging die 1 to move downward. The upper forging die 1 and the lower forging die 3 are closed to extrude the intermediate blank into shape;
[0048] 4) After the mold is closed, the slider is reset, the hydraulic ejection switch is started, and the hydraulic cylinder drives the lower forging die ejector rod 7 to eject the forging out of the die cavity of the lower forging die 3, completing a forging process.
[0049] 5) After forging, the surface oxide layer is removed by shot blasting.
Claims
1. A tool for die forging a planetary gear housing press, characterized by: The invention comprises an upper forging die (1), a lower forging die (3) and a lower forging die ejector rod (7); the upper forging die (1) is provided with an upper forging die pressing ring (2); the lower forging die (3) is provided with a lower forging die pressing ring (4); the upper forging die (1) and the lower forging die (3) cooperate to form a cavity, the lower forging die (3) is provided with a through hole at the bottom of the cavity, and the lower forging die ejector rod (7) is provided in the through hole.
2. The tooling for press die forging of planetary gear housing according to claim 1, characterized in that: The upper forging die (1) and the lower forging die (3) are cylindrical and have a flashless groove structure; the upper forging die (1) is fixed to the pressure head of the press through the upper forging die ring (2); the lower forging die (3) is fixed to the workbench of the press through the lower forging die ring (4); an upper forging die positioning pad (9) is provided between the upper forging die (1) and the pressure head, and a lower forging die positioning pad (5) is provided between the lower forging die (3) and the workbench.
3. The tooling for press die forging of planetary gear housing according to claim 2, characterized in that: The upper forging die positioning pad (9) and the lower forging die positioning pad (5) are both cylindrical with a circular groove provided on one end surface.
4. The tooling for press die forging of a planetary gear housing according to claim 2, characterized in that: The press adopts an EP-1600 electric screw press; the outer diameter of the upper forging die positioning plate (9) is Φ259 mm, the positioning groove size is Φ220 mm, and the outer diameter of the top of the upper forging die (1) is Φ219.5 mm; the outer diameter of the lower forging die positioning plate (5) is Φ359 mm, the positioning groove size is Φ260 mm, and the outer diameter of the bottom of the lower forging die (3) is Φ259.5 mm. The die height of the upper forging die (1) and the lower forging die (3) is 400 mm.
5. The tooling for press die forging of planetary gear housing according to claim 1, characterized in that: The upper forging die pressing ring (2) and the lower forging die pressing ring (4) are annular, and the upper forging die pressing ring (2) and the upper forging die (1) are matched with each other, and the matching size is Φ262mm; the lower forging die pressing ring (4) and the lower forging die (3) are matched with each other, and the matching size is Φ322mm.
6. The tooling for press die forging of planetary gear housing according to claim 1, characterized in that: The material used for the upper forging die (1) and the lower forging die (3) is 5CrNiMo with a hardness of 42~48 HRC; the upper forging die (1) and the lower forging die (3) are treated with ion nitriding, and the hardened layer depth of the working surface of the upper forging die (1) and the lower forging die (3) is 0.5~0.7mm, and the hardness is ≥600HV; the cavity surface is finely polished, and the roughness of the cavity surface of the upper forging die (1) and the lower forging die (3) is ≤Ra0.8, and the roughness of the other surfaces is ≤Ra6.
3.
7. The tooling for press die forging of planetary gear housing according to claim 1, characterized in that: The lower forging die ejector pin (7) is located at the center of the lower forging die (3), and is made of 5CrNiMo with a hardness of 40-45HRC. The lower forging die ejector pin (7) is ion nitrided, and the working surface of the lower forging die ejector pin (7) has a hardening layer depth of 0.5-0.7mm and a hardness of ≥600HV. The roughness of the portion of the cavity surface formed by the lower forging die ejector pin (7) is ≤Ra0.8, and the roughness of the remaining surface is ≤Ra6.
3.
8. The tooling for press die forging of a planetary gear housing according to claim 1, characterized in that: The sharp corners of the upper forging die (1), the lower forging die ejector rod (7) and the lower forging die (3) are all rounded R1 to R2.