Hot gas expansion gas source supply system and method for improving production takt

Abstract

The invention discloses a hot gas expansion gas source supply system and method for improving the production takt. The method comprises the following steps that nitrogen is compressed to first pressure through a first-stage supercharger and then enters a medium-pressure gas cylinder to be stored, and nitrogen in the medium-pressure gas cylinder is compressed to second pressure through a second-stage supercharger and then enters a high-pressure gas cylinder to be stored; gas supply and pressurization are conducted on the workpiece through the medium-pressure gas cylinder and / or the high-pressure gas cylinder; after pressurizing is completed, when the pressure of the nitrogen in the workpiece is larger than the y value, the nitrogen is recycled into a medium-pressure gas cylinder; when the pressure of the nitrogen in the workpiece is within the range of x-y, the nitrogen is recycled as a supply gas source of the first-stage supercharger; and when the pressure of the nitrogen in the workpiece is smaller than x, directly discharging. The pressurizing mode that the gas cylinder is communicated with the workpiece is adopted, the pressure difference between the gas cylinder and the workpiece is large, and rapid gas transmission is achieved; a graded recovery scheme is adopted, so that a relatively large pressure difference is kept between the starting end and the terminating end of each path, and the recovery efficiency is improved; the device has the advantages of high gas supply speed and quick gas recovery, and the production takt of a hot gas expansion process is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of pressure-filling molding, and in particular to a hot air inflation source supply system and method for improving production rhythm. Background Art

[0002] With the development of the automobile industry, lightweighting has become a key strategy to improve vehicle fuel efficiency and reduce emissions. Hollow high-strength steel pipe fittings have become an important means to achieve lightweighting of automobiles due to their excellent mechanical properties and low weight. As an efficient and controllable manufacturing method, hot air expansion technology can produce high-quality hollow high-strength steel pipe fittings, so it is widely used in automobile manufacturing. At present, more and more car models are beginning to use hot air expansion parts, which has significantly increased the production capacity demand of hot air expansion technology.

[0003] Hot air expansion is a process that uses high-pressure gas to shape the material when it is softened at high temperature. In industry, it is achieved by heating the blank and putting it into the mold cavity, and then quickly filling it with high-pressure gas before the material temperature drops too much to force the blank to fit closely to the mold cavity. The production cycle consists of the following contents: loading-closing the mold-charging-pressure-maintaining-pressure-relieving-opening the mold-unloading. Among them, the time for loading, unloading, closing the mold and opening the mold has been difficult to break through after long-term industrial accumulation, and the remaining factors affecting the production cycle are all controlled by the gas source solution.

[0004] However, the production capacity of the hot air expansion process is mainly restricted by the supply of gas sources. The traditional gas source supply scheme has deficiencies in high-pressure gas production efficiency and gas supply speed, resulting in low production efficiency and difficulty in meeting the growing market demand. For example: In the prior art, a liquid-driven pneumatic cylinder is usually used to charge the workpiece, and its charging speed is determined by the stroke of the hydraulic cylinder. However, the upper limit of the feed speed of the hydraulic cylinder is relatively low, which limits the pressure increase rate of the workpiece. In addition, in terms of gas recovery, the existing gas source scheme usually directly recovers the gas as a gas source supplement for the first-stage booster, and its recovery speed is slow, especially for gases with a pressure of less than 3MPa.

[0005] Patent CN202087667U discloses a gas source control device for air bulging, which achieves precise control of the gas source input, i.e., the workpiece pressure-time curve, through a combination of pressure sensors, valves, and PLC hardware and software. However, the pressure supply speed of this solution has not been improved, and the production cycle of the hot air bulging process cannot be improved. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a hot air expansion gas source supply system and method for improving the production rhythm, adopts a pressurizing method of connecting a gas cylinder to a workpiece and a scheme of graded recovery, and graded pressurizes the gas through a first-stage booster and a second-stage booster, and stores the gas through medium-pressure gas cylinders and high-pressure gas cylinders respectively. The gas supply cylinder is selected according to the molding pressure of the workpiece, and the gas in the workpiece is graded and recovered; it has the advantages of fast gas supply speed and rapid gas recovery, and greatly improves the production rhythm of the hot air expansion process.

[0007] In order to solve the above technical problems, the present invention provides a method for supplying a hot air source for improving production rhythm, comprising the following steps:

[0008] S1, nitrogen is compressed to the first pressure by the first-stage booster and then stored in the medium-pressure gas cylinder, and the nitrogen in the medium-pressure gas cylinder is compressed to the second pressure by the second-stage booster and then stored in the high-pressure gas cylinder;

[0009] S2. Supply gas and pressurize the workpiece through medium-pressure gas cylinders and / or high-pressure gas cylinders;

[0010] S3, setting x and y values, wherein the y value is greater than the pressure of the medium pressure gas cylinder;

[0011] After the pressurization is completed, when the nitrogen pressure in the workpiece is greater than the y value, it is recovered to the medium-pressure gas cylinder; when the nitrogen pressure in the workpiece is within the range of xy, it is recovered as the supply gas source for the first-stage booster; when the nitrogen pressure in the workpiece is less than x, it is directly discharged.

[0012] The present invention uses a primary booster and a secondary booster to pressurize the gas in stages, and stores the gas in medium-pressure gas cylinders and high-pressure gas cylinders respectively. According to the required molding pressure of the workpiece, medium-pressure gas cylinders and / or high-pressure gas cylinders are selected to supply gas and pressurize the workpiece. Within one production cycle, the gas supply and gas replenishment of the gas cylinders are balanced, and the gas supply and replenishment are performed alternately in a cycle. Before each gas supply, the pressure in the gas cylinder can be kept at a relatively high pressure state. The recovery efficiency and the recovery speed are comprehensively considered to set the x and y values ​​of the recovery path to recover the gas in the workpiece in stages, so that a large pressure difference is maintained between the starting end and the ending end of each path, thereby improving the recovery efficiency. The invention has the advantages of fast gas supply speed and rapid gas recovery, and greatly improves the production cycle of the hot air expansion process.

[0013] Furthermore, the nitrogen entering the first-stage booster is high-purity nitrogen produced jointly by an air compressor, a cold dryer and a nitrogen generator.

[0014] Further, in S1, the first pressure is 20-50 MPa, and the second pressure is 70-100 MPa.

[0015] Furthermore, in S3, the y value is 1.2-1.5 times the pressure of the medium-pressure gas cylinder, and the x value is 3-10MPa. The recovery path judgment values ​​x and y are selected after comprehensive consideration of the recovery efficiency and recovery speed. Increasing the boundary value y for determining whether to recycle to the medium-pressure gas cylinder can increase the pressure difference between the starting end and the end end of the recovery path of the medium-pressure gas cylinder, thereby increasing the recovery speed. At the same time, due to the increase in the y value, the amount of gas filled into the medium-pressure gas cylinder is reduced, and the pressure recovery efficiency is reduced. Therefore, by adjusting the values ​​of x and y, it is possible to ensure the recovery efficiency while taking into account the recovery speed.

[0016] Further, in S2, the gas supply and pressurization of the workpiece by the medium-pressure gas cylinder and / or the high-pressure gas cylinder is specifically as follows:

[0017] When the workpiece to be formed is an easy-to-form workpiece, it is directly pressurized by supplying gas through a medium-pressure gas cylinder;

[0018] When the workpiece to be formed is a difficult-to-form workpiece, it is first pressurized to the pre-forming pressure through a medium-pressure gas cylinder, and then pressurized to the forming pressure through a high-pressure gas cylinder.

[0019] Furthermore, a workpiece whose cross-sectional change rate along the product axis direction during workpiece forming exceeds 10% or whose wall thickness exceeds 2.4 mm is a difficult-to-form workpiece; otherwise, it is an easy-to-form workpiece.

[0020] Furthermore, the preforming pressure is 0.55-0.65 times the workpiece forming pressure.

[0021] Furthermore, for workpieces that are easy to form, the pressure of the medium-pressure gas cylinder before supplying gas is more than 30% higher than the forming pressure of the workpiece. The pressure in the gas cylinder is kept at a relatively high pressure before each gas supply.

[0022] Furthermore, for workpieces that are difficult to form, the pressure before the medium-pressure gas cylinder supplies gas is more than 30% higher than the pre-forming pressure of the workpiece, and the pressure before the high-pressure gas cylinder supplies gas is more than 30% higher than the forming pressure of the workpiece.

[0023] Furthermore, the capacity of the medium-pressure gas cylinder and the high-pressure gas cylinder is greater than 3 times the gas supply volume for workpiece molding. The large-capacity gas cylinder has a smaller pressure drop when supplying gas, and combined with the high pressure state in the gas cylinder, it is conducive to the formation of a pressure difference between the gas cylinder and the workpiece during pressure molding, which significantly improves the pressure increase speed of the hot gas expansion process and improves the production cycle.

[0024] The second aspect of the present invention provides a hot air source supply system for improving production rhythm, which is used to implement the method described in the first aspect, including a first-stage booster, a medium-pressure gas cylinder, a second-stage booster and a high-pressure gas cylinder connected in sequence, and the medium-pressure gas cylinder and the high-pressure gas cylinder are provided with an outlet for supplying gas to the workpiece.

[0025] Beneficial effects of the present invention:

[0026] The present invention uses a first-stage booster and a second-stage booster to pressurize the gas in stages, and stores the gas in medium-pressure gas cylinders and high-pressure gas cylinders respectively. According to the required molding pressure of the workpiece, medium-pressure gas cylinders and / or high-pressure gas cylinders are selected to supply gas and pressurize the workpiece. Within one production cycle, the gas supply and gas replenishment of the gas cylinders are balanced. Before each gas supply, the pressure in the gas cylinder can be kept at a relatively high pressure state. Combined with the design of large-capacity gas cylinders, a large pressure difference can be ensured between the gas cylinder and the workpiece during the gas supply process, thereby significantly improving the pressure increase speed of the hot air expansion process and thereby improving the production cycle.

[0027] The present invention comprehensively considers the recovery efficiency and the recovery speed to set the x and y values ​​for determining the recovery path to perform graded recovery of the gas in the workpiece.

[0028] The hot air expansion gas source supply method of the present invention has the advantages of fast gas supply speed and rapid gas recovery, which greatly improves the production rhythm of the hot air expansion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of pressurized gas supply of a hot gas expansion source supply method for improving production rhythm of the present invention;

[0031] Figure 2 It is a schematic diagram of gas source recovery of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Reference Figure 1 As shown, this embodiment provides a method for supplying a hot air source to improve production rhythm, including the following steps:

[0034] S1, nitrogen is compressed to the first pressure by the first-stage booster and then stored in the medium-pressure gas cylinder, and the nitrogen in the medium-pressure gas cylinder is compressed to the second pressure by the second-stage booster and then stored in the high-pressure gas cylinder;

[0035] Wherein, the first pressure is 20-50MPa, and the second pressure is 70-100MPa;

[0036] S2. Supply gas and pressurize the workpiece through medium-pressure gas cylinders and / or high-pressure gas cylinders;

[0037] Among them, when the workpiece to be formed is an easy-to-form workpiece, it is directly pressurized through the medium-pressure gas cylinder; when the workpiece to be formed is a difficult-to-form workpiece, it is first pressurized to the pre-forming pressure through the medium-pressure gas cylinder, and then pressurized to the forming pressure through the high-pressure gas cylinder; when the workpiece is formed, a workpiece with a cross-sectional change rate exceeding 10% along the product axis direction or a wall thickness exceeding 2.4mm is a difficult-to-form workpiece; otherwise, it is an easy-to-form workpiece.

[0038] S3, setting x and y values, wherein the y value is 1.2-1.5 times the pressure of the medium pressure gas cylinder, and the x value is 3-10 MPa;

[0039] refer to Figure 2 After the pressurization is completed, when the nitrogen pressure in the workpiece is greater than the y value, it is recovered to the medium-pressure gas cylinder; when the nitrogen pressure in the workpiece is within the range of xy, it is recovered as the supply gas source for the first-stage booster; when the nitrogen pressure in the workpiece is less than x, it is directly discharged.

[0040] This embodiment uses a first-stage booster and a second-stage booster to pressurize the gas in stages, and stores the gas in medium-pressure gas cylinders and high-pressure gas cylinders respectively. According to the required molding pressure of the workpiece, medium-pressure gas cylinders and / or high-pressure gas cylinders are selected to supply gas and pressurize the workpiece. Within one production cycle, the gas supply and gas replenishment of the gas cylinders are balanced, and the gas supply and replenishment are performed alternately in a cycle. Before each gas supply, the pressure in the gas cylinder can be maintained at a relatively high pressure state; the recovery efficiency and recovery speed are comprehensively considered to set the x and y values ​​of the recovery path to recover the gas in the workpiece in stages, so that a large pressure difference is maintained between the starting end and the ending end of each path, thereby improving the recovery efficiency; it has the advantages of fast gas supply speed and rapid gas recovery, which greatly improves the production cycle of the hot air expansion process.

[0041] As a preferred embodiment, the preforming pressure is 0.55-0.65 times the workpiece forming pressure.

[0042] As a preferred embodiment, for easy-to-form workpieces, the pressure of the medium-pressure gas cylinder before supplying gas is more than 30% higher than the forming pressure of the workpiece; for difficult-to-form workpieces, the pressure of the medium-pressure gas cylinder before supplying gas is more than 30% higher than the pre-forming pressure of the workpiece, and the pressure of the high-pressure gas cylinder before supplying gas is more than 30% higher than the forming pressure of the workpiece, ensuring that the pressure in the gas cylinder remains at a relatively high pressure before each gas supply.

[0043] As a preferred embodiment, the capacity of the medium-pressure gas cylinder and the high-pressure gas cylinder is greater than 3 times the gas supply for workpiece molding. The large-capacity gas cylinder has a smaller pressure drop when supplying gas, and combined with the high pressure state in the gas cylinder, it is conducive to the formation of a pressure difference between the gas cylinder and the workpiece during pressure molding, which significantly improves the pressure increase speed of the hot gas expansion process and improves the production cycle.

[0044] Another embodiment provides a hot air expansion source supply system for improving production rhythm, which is used to implement the method described in the first aspect, including a first-stage booster, a medium-pressure gas cylinder, a second-stage booster and a high-pressure gas cylinder connected in sequence, and the medium-pressure gas cylinder and the high-pressure gas cylinder are provided with an outlet for supplying gas to the workpiece.

[0045] Example 1

[0046] This embodiment uses a medium-pressure gas cylinder with a capacity four times the workpiece gas supply to connect the A-pillar pipe fitting (the workpiece molding pressure is 30MPa) for pressurization, and the medium-pressure gas cylinder is replenished with gas through a first-stage supercharger. The pressure of the medium-pressure gas cylinder is kept high relative to the workpiece molding pressure, and the value is controlled within the range of 40-45MPa, so that the pressure inside the workpiece is raised to 30MPa. For gas with a pressure greater than 5MPa, it is recovered as the gas source supply for the first-stage compressor, and for gas with a pressure less than 5MPa, it is directly discharged into the atmosphere.

[0047] Example 2

[0048] This embodiment uses a medium-pressure gas cylinder with a gas supply capacity of 4 times the workpiece to connect the A-pillar pipe fitting (the workpiece molding pressure is 60MPa) for pre-charging. The pressure of the medium-pressure gas cylinder is controlled within the range of 40-45MPa, so that the pressure inside the workpiece rises to 30MPa. Subsequently, a high-pressure gas cylinder is used to continue to increase the pressure of the workpiece until it reaches 60MPa. For gases with a pressure greater than 48MPa, they are recovered to the medium-pressure gas cylinder, for gases with a pressure greater than 5MPa and less than 48MPa, they are recovered as the gas source supply for the first-stage compressor, and for gases with a pressure less than 5MPa, they are directly discharged into the atmosphere.

[0049] Comparative Example 1

[0050] The comparative example uses a liquid-driven pneumatic cylinder to directly pressurize the A-pillar pipe fitting of the same embodiment 1, so that the pressure inside the workpiece rises to 30 MPa. In terms of recycling, no pressure level is distinguished, and all are recycled as the gas source supply for the first-stage compressor.

[0051] Comparative Example 2

[0052] The comparative example uses a liquid-driven pneumatic cylinder to directly pressurize the A-pillar pipe fitting of Example 2, so that the pressure inside the workpiece rises to 60 MPa. In terms of recycling, no pressure level is distinguished, and all are recycled as the gas source supply for the first-stage compressor.

[0053] The gas supply time and recovery time of different gas source supply schemes of Example 1-2 and Comparative Example 1-2 are shown in Table 1.

[0054] Table 1

[0055] Group Gas supply time Recycling time Example 1 3s 5s Example 2 6s 8s Comparative Example 1 6s 11s Comparative Example 2 11s 14s

[0056] As can be seen from Table 1, from the comparison between Example 1 and Comparative Example 1 and between Example 2 and Comparative Example 2, it can be seen that the schemes of Examples 1 and 2 of the present invention significantly reduce the gas supply time and the recovery time, and thus can greatly improve the production cycle.

[0057] In summary, the present invention uses a first-stage booster and a second-stage booster to grade and pressurize the gas, and stores it in medium-pressure gas cylinders and high-pressure gas cylinders respectively. According to the required molding pressure of the workpiece, medium-pressure gas cylinders and / or high-pressure gas cylinders are selected to supply and pressurize the workpiece. The gas supply and gas replenishment of the gas cylinders are balanced within one production cycle. The pressure in the gas cylinder can be kept at a relatively high pressure before each gas supply. Combined with the large-capacity gas cylinder design, it is ensured that a large pressure difference can be maintained between the gas cylinder and the workpiece during the gas supply process, which significantly improves the pressure increase speed of the hot air expansion process and thus improves the production cycle. The present invention comprehensively considers the recovery efficiency and the recovery speed to set the x and y values ​​of the recovery path to grade the gas recovery in the workpiece. The hot air expansion gas source supply method of the present invention has the advantages of fast gas supply speed and rapid gas recovery, which greatly improves the production cycle of the hot air expansion process.

[0058] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for supplying a hot air source for improving production tact, characterized in that: The steps include: S1, nitrogen is compressed to the first pressure by the first-stage booster and then stored in the medium-pressure gas cylinder, and the nitrogen in the medium-pressure gas cylinder is compressed to the second pressure by the second-stage booster and then stored in the high-pressure gas cylinder; S2. Supply gas and pressurize the workpiece through medium-pressure gas cylinders and / or high-pressure gas cylinders; S3, setting x and y values, wherein the y value is greater than the pressure of the medium pressure gas cylinder; After the pressurization is completed, when the nitrogen pressure in the workpiece is greater than the y value, it is recovered to the medium-pressure gas cylinder; when the nitrogen pressure in the workpiece is within the range of xy, it is recovered as the supply gas source for the first-stage booster; when the nitrogen pressure in the workpiece is less than x, it is directly discharged.

2. The method for supplying hot air source for improving production cycle according to claim 1, characterized in that: In S1, the first pressure is 20-50 MPa, and the second pressure is 70-100 MPa.

3. The hot air source supply method for improving production cycle according to claim 1, characterized in that: In S3, the y value is 1.2-1.5 times the pressure of the medium-pressure gas cylinder, and the x value is 3-10 MPa.

4. The method for supplying a hot air source for improving production cycle according to claim 1, characterized in that: In S2, the gas supply and pressurization of the workpiece by using a medium-pressure gas cylinder and / or a high-pressure gas cylinder is specifically as follows: When the workpiece to be formed is an easy-to-form workpiece, it is directly pressurized by supplying gas through a medium-pressure gas cylinder; When the workpiece to be formed is a difficult-to-form workpiece, it is first pressurized to the pre-forming pressure through a medium-pressure gas cylinder, and then pressurized to the forming pressure through a high-pressure gas cylinder.

5. The method for supplying hot air source for improving production cycle according to claim 4, characterized in that: Workpieces with a cross-sectional change rate exceeding 10% along the product axis during forming or a formed workpiece wall thickness exceeding 2.4 mm are difficult to form; otherwise, they are easy to form.

6. The hot air source supply method for improving production cycle according to claim 4, characterized in that: The preforming pressure is 0.4-0.7 times the workpiece forming pressure.

7. The method for supplying hot air source for improving production cycle according to claim 4, characterized in that: For workpieces that are easy to form, the pressure before the medium-pressure gas cylinder supplies gas is more than 30% higher than the forming pressure of the workpiece.

8. The method for supplying a hot air source for improving production cycle according to claim 4, characterized in that: For difficult-to-form workpieces, the pressure before the medium-pressure gas cylinder supplies gas is more than 30% higher than the pre-forming pressure of the workpiece, and the pressure before the high-pressure gas cylinder supplies gas is more than 30% higher than the forming pressure of the workpiece.

9. The method for supplying a hot air source for improving production cycle according to claim 1, characterized in that: The capacity of the medium-pressure gas cylinder and the high-pressure gas cylinder is greater than 3 times the gas supply for workpiece molding.

10. A hot air source supply system for improving production rhythm, characterized in that: The method used to implement any one of claims 1 to 9 comprises a first-stage booster, a medium-pressure gas cylinder, a second-stage booster and a high-pressure gas cylinder connected in sequence, wherein the medium-pressure gas cylinder and the high-pressure gas cylinder are provided with gas outlets for supplying gas to the workpiece.

Images