A closed forging die and forging process for a drive shaft

Abstract

The present invention belongs to the field of forging technology, and specifically relates to a closed forging die and forging process for a drive shaft. The forging die comprises an upper die and a lower die, with a left cylinder and a right cylinder arranged on opposite sides. The left cylinder is arranged on a left fixed plate, and a left push rod is connected to the left fixed plate. The right cylinder is arranged on a right fixed plate, and a right push rod is connected to the right fixed plate. Limit sensors are arranged on the left fixed plate and the right fixed plate. The output ends of the left push rod and the right push rod are provided with limit grooves that match the shapes of the two ends of the drive shaft. The present invention also discloses a forging process. When forging the drive shaft, the drive shaft is horizontally parted, and the left and right sides of the blank are extruded and formed by the left and right push rods, so that the blank is formed in a die cavity closed on all sides, and no lateral flash is generated. Therefore, there is no need to add a trimming process in the subsequent process, which greatly improves the material utilization rate, effectively improves the production efficiency, and reduces the production cost.

Description

Technical Field

[0001] The invention belongs to the technical field of forging industry, and in particular relates to a closed forging die and a forging process for a drive shaft. Background Art

[0002] In the existing technology, a large part of various shaft products are made by open die forging. However, the forgings produced by open die forging have flash, which requires a subsequent trimming process to remove the flash. According to customer needs and the requirements of reducing costs, closed die forging technology is now adopted. However, conventional closed die forging, such as Figure 4 As shown in the driving shaft forging diagram, due to the long length of the forging, the product is not easy to be taken out when it is placed vertically into the cavity, and it is necessary to add an ejector mechanism to the lower die. For example, a closed forging die for a coupling disclosed in publication number CN 111974926 A has a lower ejector rod penetrating the lower die pad for lifting the lower ejector block when demolding, which makes the die structure more complicated; and when the forging is placed vertically into the die cavity, the forging still needs to be put at a draft angle, and the weight of the forging will still increase, so it cannot meet customer needs and the company's requirements for cost reduction.

[0003] Therefore, the above problems are issues that should be considered and solved during the forging process of the drive shaft. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a closed forging die and forging process for a drive shaft to completely solve the above problems.

[0005] In order to solve the above technical problems, the present invention provides a closed forging die for a drive shaft, including a die body, the die body including an upper die and a lower die, a left cylinder and a right cylinder are relatively provided on both sides of the die body, the left cylinder is arranged on a left fixed plate, the left fixed plate is connected to a left push rod, the right cylinder is arranged on a right fixed plate, the right fixed plate is connected to a right push rod, limit sensors are provided on the left fixed plate and the output ends of the left push rod and the right push rod are provided with limit grooves that are adapted to the shapes of the two ends of the drive shaft.

[0006] A further improvement of the present invention is that the lower mold is arranged on a base, the upper mold is fixed to an upper fixed plate via a connecting seat, the left push rod is connected to the left fixed plate via a left connecting plate, and the right push rod is connected to the right fixed plate via a right connecting plate.

[0007] A further improvement of the present invention is that the connecting ends of the left push rod and the right push rod are both provided with limit blocks.

[0008] The present invention also provides a closed forging process for a drive shaft, which specifically includes the following steps: unloading - heating of the blank - forming - heat treatment - shot blasting - flaw detection - inspection and warehousing. In the forming step, the qualified heated blank is first placed in the cavity of the lower die, the upper die moves downward to close the die, the left and right cylinders drive the left and right push rods to move inward, the push rods push the blank to complete the forming, and then the upper die moves upward to open the die, the left and right cylinders drive the left and right push rods to retreat, and the forging is taken out.

[0009] A further improvement of the present invention is that in the molding step, before placing the blank into the mold, a release agent is first sprayed into the mold.

[0010] A further improvement of the present invention is that a pretreatment step is included before the blanking process, in which impurities on the surface of the blank are polished by a polishing device to remove impurities and defects on the surface of the blank, and then the polished blank is cleaned multiple times, dried, and set aside.

[0011] A further improvement of the present invention is that in the shot blasting step, the forging is sequentially ground and shot peened, the grinding includes circular grinding and chamfering grinding, and the shot blasting is to place the forging in a shot blasting machine to remove burrs and oxide scales, and then perform surface phosphorus saponification treatment to obtain a precisely forged forging product workpiece before entering the next process.

[0012] A further improvement of the present invention is that in the flaw detection step, the magnetic suspension is sprayed first, and then magnetic detection is performed by a flaw detector, and this is repeated twice, and finally the finished product is demagnetized and inspected.

[0013] A further improvement of the present invention is that in the flaw detection step, each surface of the forging is required to be 100% free of cracks and folds. If there are cracks, they are marked with chalk, placed in the waiting area, and then tested again after polishing. The workpieces that pass the flaw detection are inspected for corresponding specification parameters, and those that meet the standards are sent out for storage.

[0014] Compared with the prior art, the present invention can achieve the following technical effects: when forging the drive shaft, the drive shaft is horizontally divided and the left and right sides of the blank are extruded by left and right push rods. The forging does not require an additional draft angle and does not require an ejection mechanism. The mold structure is simplified, so that the blank is formed in a mold cavity that is closed on all sides without generating lateral flash. Therefore, there is no need to add a trimming process in the subsequent process, which greatly improves material utilization and effectively improves production efficiency and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1It is a schematic diagram of the forging die in the present invention; Figure 2 Schematic diagram of the internal structure of the forging die in the present invention; Figure 3 It is a schematic diagram of the structure of the left and right push rods in the present invention; Figure 4 is a schematic diagram of a drive shaft forging in the present invention; Among them, 1-upper die, 2-lower die, 3-base, 4-connecting seat, 5-upper fixed plate, 6-left cylinder, 7-right cylinder, 8-left fixed plate, 9-left connecting plate, 10-left push rod, 11-right fixed plate, 12-right connecting plate, 13-right push rod, 14-limit block, 15-limit sensor, 16-limit slot. DETAILED DESCRIPTION

[0016] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0017] The present embodiment provides a closed forging die and forging process for a drive shaft, wherein the forging die comprises a die body, the die body comprises an upper die 1 and a lower die 2, the lower die 2 is arranged on a base 3, the upper die 1 is fixed on an upper fixed plate 5 through a connecting seat 4, a left oil cylinder 6 and a right oil cylinder 7 are arranged on opposite sides of the die body, the left oil cylinder 6 is arranged on a left fixed plate 8, a left push rod 10 is connected to the left fixed plate 8 through a left connecting plate 9, the right oil cylinder 7 is arranged on a right fixed plate 11, the right fixed plate 11 is connected to a right push rod 13 through a right connecting plate 12, and the connecting ends of the left push rod 10 and the right push rod 13 are both provided with a limit block 14 to ensure the advancement distance of the left and right push rods and the length of the forging, the left fixed plate 8 and the right fixed plate 11 are both provided with a limit sensor 15, so that the left and right push rods can stop automatically when they are advanced to a suitable distance, and the output ends of the left push rod 10 and the right push rod 13 are both provided with a limit groove 16 that matches the shape of the two ends of the drive shaft.

[0018] The closed forging process of a drive shaft provided in this embodiment specifically includes the following steps: (1) Unloading: The blank is pre-treated before unloading, and the impurities on the surface of the blank are polished by a polishing device to remove impurities and defects on the surface of the blank. The polished blank is then cleaned several times, dried, and set aside; (2) Billet heating: Heat the billet to 1150°C to make the billet have sufficient plasticity for forging; (3) Molding: First, spray the mold release agent into the mold, then put the heated qualified blank into the cavity of the lower mold, the upper mold moves downward to close the mold, the left and right cylinders drive the left and right push rods to move inward, the push rods push the blank to complete the molding, then the upper mold moves upward to open the mold, the left and right cylinders drive the left and right push rods to retreat, and the forging is taken out; (4) Heat treatment: heat treatment of the obtained forgings; (5) Shot blasting: In the shot blasting step, the forging is polished and shot blasted in sequence. The polishing includes circular polishing and chamfer polishing. The shot blasting is to put the forging into a shot blasting machine to remove burrs and oxide scales, and then perform surface phosphorus saponification treatment to obtain a precisely forged forging product workpiece before entering the next process; (6) Flaw detection, inspection and storage: In the flaw detection step, the magnetic suspension is sprayed first, and then the magnetic detection is performed by the flaw detector, and this is repeated twice. Finally, the finished product is demagnetized and inspected. During the flaw detection, it is required that all surfaces of the forgings are 100% free of cracks and folds. If there are cracks, they are marked with chalk and placed in the waiting area. After polishing, the flaw detection is repeated again. The qualified workpieces are inspected for the corresponding specifications and parameters, and those that meet the standards are sent to the warehouse.

[0019] The closed forging process for the drive shaft of this embodiment simplifies the forging process and solves the problem that the forgings produced by open die forging in the prior art have flash and require a subsequent trimming process. When forging the drive shaft, this embodiment divides the drive shaft horizontally and then extrude the left and right sides of the blank through the left and right push rods. The forging does not require an additional draft angle and does not require an ejection mechanism. The die structure is simplified, so that the blank is formed in a closed die cavity on all sides without generating lateral flash. Therefore, there is no need to add a trimming process in the subsequent process, which greatly improves material utilization and effectively improves production efficiency and reduces production costs.

Claims

1. A closed forging die for a drive shaft, comprising a die body, characterized in that: The mold body includes an upper mold and a lower mold, and a left cylinder and a right cylinder are relatively arranged on both sides of the mold body. The left cylinder is arranged on a left fixed plate, and the left fixed plate is connected to a left push rod. The right cylinder is arranged on a right fixed plate, and the right fixed plate is connected to a right push rod. Limit sensors are arranged on the left fixed plate and the right fixed plate, and the output ends of the left push rod and the right push rod are provided with limit grooves that are adapted to the shapes of the two ends of the drive shaft.

2. A closed forging die for a drive shaft according to claim 1, comprising a die body, characterized in that: The lower mold is arranged on a base, the upper mold is fixed on an upper fixed plate via a connecting seat, the left push rod is connected to the left fixed plate via a left connecting plate, and the right push rod is connected to the right fixed plate via a right connecting plate.

3. The closed forging die for a drive shaft according to claim 1, comprising a die body, characterized in that: The connecting ends of the left push rod and the right push rod are both provided with limit blocks.

4. A closed forging process for a drive shaft using the closed forging die for a drive shaft as claimed in any one of claims 1 to 3, characterized in that: Specifically, the following steps are included: unloading - heating of blanks - forming - heat treatment - shot blasting - flaw detection - inspection and warehousing. In the forming step, firstly, the qualified heated blank is placed in the cavity of the lower die, the upper die moves downward to close the die, the left and right oil cylinders drive the left and right push rods to move inward, the push rods push the blank to complete the forming, and then the upper die moves upward to open the die, the left and right oil cylinders drive the left and right push rods to retreat, and the forging is taken out.

5. A closed forging process for a drive shaft according to claim 4, characterized in that: In the forming step, before placing the blank into the mold, a release agent is sprayed into the mold.

6. A closed forging process for a drive shaft according to claim 4, characterized in that: Before the blanking process, a pretreatment step is also included, in which impurities on the surface of the blank are polished by a polishing device to remove impurities and defects on the surface of the blank, and then the polished blank is cleaned multiple times and dried for standby use.

7. A closed forging process for a drive shaft according to claim 4, characterized in that: In the shot blasting step, the forging is polished and shot blasted in sequence. The polishing includes circular polishing and chamfer polishing. The shot blasting is to put the forging into a shot blasting machine to remove burrs and oxide scales, and then perform surface phosphorus saponification treatment to obtain a precisely forged forging product workpiece and enter the next process.

8. The closed forging process for a drive shaft according to claim 4, characterized in that: In the flaw detection step, the magnetic suspension is sprayed first, and then magnetic detection is performed by a flaw detector, and this is repeated twice. Finally, the finished product is demagnetized and then inspected.

9. A closed forging process for a drive shaft according to claim 4, characterized in that: In the flaw detection step, it is required that each surface of the forging is 100% free of cracks and folds. If there are cracks, they are marked with chalk and placed in the waiting area. After polishing, the flaw detection is repeated again. The qualified workpieces are inspected for the corresponding specification parameters, and those that meet the standards are sent to the warehouse.

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