Powder metallurgy gearbox chain wheel production process

Abstract

The invention relates to a powder metallurgy gearbox chain wheel production process, which comprises the following steps of: selecting materials, and determining the powder material type according to the service condition and the strength of a chain wheel in combination with the material standard of powder metallurgy; mold processing: manufacturing and processing a corresponding forming mold according to the size specification of the blank of the chain wheel and the size change rate of the powder material in the process; forming and pressing: according to the density specification and height dimension requirements of the chain wheel, selecting a corresponding powder material and a pressing machine with corresponding tonnage to press a formed part; sintering is conducted, specifically, the formed part of the chain wheel is sintered at the set temperature; carrying out carbonitriding heat treatment; machining: machining an inner hole of the chain wheel; and cleaning: putting the chain wheel subjected to burr brushing into a hydrocarbon cleaning machine for cleaning, removing impurities on the surface, and ensuring the cleanliness of the rotor. The chain wheel produced through the technology can meet the requirement of a commercial vehicle for the size precision of the chain wheel; compared with a traditional forging process, the cost is saved by about 40%, the material utilization rate is high, the product weight is light, and the automobile lightweight development requirement is met.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, and specifically to a powder metallurgy gearbox sprocket manufacturing process. Background Technology

[0002] Existing gearbox sprockets are all machined from castings, which is determined by the structure of the sprocket. However, the machining allowance for castings is very large, the machining cost is very high, and the waste of materials is very serious. On the other hand, the existing powder metallurgy process can form the sprocket in one step, and only the inner diameter of the drive sprocket needs to be machined with minimal machining, while the driven sprocket does not need to be machined. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems existing in the prior art and provide a powder metallurgy gearbox sprocket manufacturing process to improve material utilization, reduce product weight, and greatly save costs.

[0004] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: A powder metallurgy gearbox sprocket manufacturing process, comprising the following steps: Step S1: Material selection. Based on the usage and strength of the gearbox sprocket, determine the type of powder material according to the material standards of powder metallurgy. Step S2: Mold processing. Based on the blank size and specifications of the gearbox sprocket, and combined with the dimensional change rate of the powder material during the process, a corresponding molding mold is made. Step S3: Molding and pressing. Based on the density specifications and height requirements of the gearbox sprocket, select the appropriate powder and press of the appropriate tonnage to press the molded parts. Step S4: Sintering, the molded parts of the gearbox sprocket are sintered at a set temperature; Step S5: Carbonitriding heat treatment. Carbonitriding is carried out for a period of time under the set temperature conditions. Then, it is placed in quenching oil at a certain temperature for quenching. After quenching, it is tempered for a period of time at the tempering temperature to ensure the wear resistance of the sprocket surface and improve the toughness of the sprocket core. Step S6: Machining, machining the inner hole of the gearbox sprocket; Step S7: Cleaning. Place the deburred gearbox sprocket into a hydrocarbon cleaning machine to clean it, remove surface debris, and ensure the cleanliness of the rotor so that it can be directly assembled and used by the user.

[0005] Furthermore, in step S1, the powder material used for the gearbox sprocket is MPIF FL-4005, and the material formula is: Mo: 0.39-0.5%, C: 0.4%, balance: Fe.

[0006] Furthermore, in step S2, the molding die is processed through conventional machining, heat treatment, wire cutting, electrical discharge machining, polishing, grinding, and inspection processes.

[0007] Furthermore, in step S3, an 800T press is used to press the molded part, and the density of the molded part is 7.1 g / cm³. 3 The density requirement for the front, back, left, and right sides of the sprocket is less than 0.05.

[0008] Furthermore, in step S4, the sintering temperature is selected as 1120℃, and a graphite plate is used as a tooling for auxiliary sintering to ensure minimal deformation and prevent sprocket deformation.

[0009] Furthermore, in step S5, the carbonitriding temperature is set to 850°C and the tempering temperature is set to 180°C.

[0010] Furthermore, in step S6, the tolerance of the machined inner hole is ensured to be within 0.03.

[0011] The beneficial effects of this invention are: The gearbox sprockets produced using the process of this invention can meet the dimensional accuracy requirements of commercial vehicles; they save nearly 40% of the cost compared to traditional forging processes, improve material utilization, reduce product weight, and meet the requirements of lightweight automotive development. Attached Figure Description

[0012] Figure 1 A schematic diagram of a gearbox sprocket product manufactured using the process of this invention; Figure 2 This is a schematic diagram of the molding die structure of the present invention.

[0013] The numbers in the diagram are as follows: 1. Middle die, 2. Upper punch, 3. Upper first punch pad, 4. Upper first punch washer, 5. Upper punch cover, 6. Lower punch, 7. Lower punch pad, 8. Lower punch washer, 9. Lower punch cover, 10. Lower second punch, 11. Lower second punch pad, 12. Lower second punch cover, 13. Mandrel cover, 14. Mandrel, 15. Middle die cover, 16. Middle die seat. Detailed Implementation

[0014] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0015] A powder metallurgy gearbox sprocket manufacturing process, comprising the following steps: Step S1: Material selection. Based on the usage and strength of the gearbox sprocket, determine the type of powder material according to the material standards of powder metallurgy. Step S2: Mold processing. Based on the blank dimensions and specifications of the gearbox sprocket, and considering the dimensional change rate of the powder material during the process, a corresponding molding mold is fabricated, such as... Figure 2 As shown, the forming mold has a mandrel structure that reduces the machining of the inner hole, and its lower punch structure can ensure that the lower punch and the middle die have a fixed positional relationship, thereby ensuring the stability of the positional accuracy of the entire product and meeting the product accuracy requirements. Step S3: Molding and pressing. Based on the density specifications and height requirements of the gearbox sprocket, select the appropriate powder and press of the appropriate tonnage to press the molded parts. Step S4: Sintering, the molded parts of the gearbox sprocket are sintered at a set temperature; Step S5: Carbonitriding heat treatment. Carbonitriding is carried out for a period of time under the set temperature conditions. Then, it is placed in quenching oil at a certain temperature for quenching. After quenching, it is tempered for a period of time at the tempering temperature to ensure the wear resistance of the sprocket surface and improve the toughness of the sprocket core. Step S6: Machining, machining the inner hole of the gearbox sprocket; Step S7: Cleaning. Place the deburred gearbox sprocket into a hydrocarbon cleaning machine to remove surface debris and ensure the rotor is clean. Figure 1 As shown, this allows users to assemble and use it directly.

[0016] In step S1, the powder material used for the gearbox sprocket is MPIF FL-4005, and the material formula is: Mo: 0.39-0.5%, C: 0.4%, balance: Fe.

[0017] In step S2, the molding die is processed through conventional machining, heat treatment, wire cutting, electrical discharge machining, polishing, grinding and inspection.

[0018] In step S3, an 800T press is used to press the molded part, and the density of the molded part is 7.1 g / cm³. 3 The density requirement for the front, back, left, and right sides of the sprocket is less than 0.05.

[0019] In step S4, the sintering temperature is selected as 1120℃, and a graphite plate is used as a tooling to assist in sintering, so as to ensure minimal deformation and prevent sprocket deformation.

[0020] In step S5, the carbonitriding temperature is set to 850°C and the tempering temperature is set to 180°C.

[0021] In step S6, the tolerance of the machined inner hole is ensured to be within 0.03.

[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A powder metallurgy gearbox sprocket manufacturing process, characterized in that, The process includes the following steps: Step S1: Material selection. Based on the usage and strength of the gearbox sprocket, determine the type of powder material according to the material standards of powder metallurgy. Step S2: Mold processing. Based on the blank size and specifications of the gearbox sprocket, and combined with the dimensional change rate of the powder material during the process, a corresponding molding mold is made. Step S3: Molding and pressing. Based on the density specifications and height requirements of the gearbox sprocket, select the appropriate powder and press of the appropriate tonnage to press the molded parts. Step S4: Sintering, the molded parts of the gearbox sprocket are sintered at a set temperature; Step S5: Carbonitriding heat treatment. Carbonitriding is carried out for a period of time under the set temperature conditions. Then, it is placed in quenching oil at a certain temperature for quenching. After quenching, it is tempered for a period of time at the tempering temperature to ensure the wear resistance of the sprocket surface and improve the toughness of the sprocket core. Step S6: Machining, machining the inner hole of the gearbox sprocket; Step S7: Cleaning. Place the deburred gearbox sprocket into a hydrocarbon cleaning machine to clean it, remove surface debris, and ensure the cleanliness of the rotor so that it can be directly assembled and used by the user.

2. The powder metallurgy signal disk manufacturing process according to claim 1, characterized in that, In step S1, the powder material used for the gearbox sprocket is MPIF FL-4005, and the material formula is: Mo: 0.39-0.5%, C: 0.4%, balance: Fe.

3. The powder metallurgy signal disk manufacturing process according to claim 1, characterized in that, In step S2, the molding die is processed through conventional machining, heat treatment, wire cutting, electrical discharge machining, polishing, grinding and inspection.

4. The powder metallurgy signal disk manufacturing process according to claim 1, characterized in that, In step S3, an 800T press is used to press the molded part, and the density of the molded part is 7.1 g / cm³. 3 The density requirement for the front, back, left, and right sides of the sprocket is less than 0.

05.

5. The powder metallurgy signal disk manufacturing process according to claim 1, characterized in that, In step S4, the sintering temperature is selected as 1120℃, and a graphite plate is used as a tooling to assist in sintering, so as to ensure minimal deformation and prevent sprocket deformation.

6. The powder metallurgy signal disk manufacturing process according to claim 1, characterized in that, In step S5, the carbonitriding temperature is set to 850°C and the tempering temperature is set to 180°C.

7. The powder metallurgy signal disk manufacturing process according to claim 1, characterized in that, In step S6, the tolerance of the machined inner hole is ensured to be within 0.03.

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