CN102228926A - Liquid-charging and forming method of two-way pressurizing pipe - Google Patents

Abstract

The invention relates to a liquid-charging and forming method of a two-way pressurizing pipe, which comprises the steps of: 1, pre-forming a tubular product; 2, charging high-pressure liquid in a pre-formed tube blank, and sealing the pre-formed tube blank; 3, opening an exhaust hole, charging high-pressure liquid into a die cavity from a pressurizing hole, and discharging air in the die cavity for sealing the die cavity; 4, regulating pressures inside and outside the pre-formed tube blank through an overflow valve and a high-pressure source, and starting forming; 5, after formation is completed, discharging pressures inside and outside the tubular product, and discharging the high-pressure liquid in the die cavity; and 6, removing surplus materials of parts. The forming method provided by the invention is based on a tubular product liquid-charging and forming technology; and the formed part has the advantages of high precision, good quality, capability of forming special materials and parts with complex structures, and the like. The invention has the advantages of large forming limit of the tubular product, high strength and rigidity, uniform distribution of wall thickness of a workpiece, high material utilization rate, good surface quality of the formed part, and the like.

Description

A liquid-filled forming method for two-way pressurized pipe

technical field

The invention belongs to the field of metal pressure processing, and in particular relates to a liquid-filled forming method for a two-way pressurized pipe.

Background technique

Automobile lightweight is the main trend of today's automobile manufacturing industry. In recent years, with the increasingly urgent requirements for energy saving and emission reduction and the continuous development of lightweight technology, hollow structural parts have appeared in the field of automobile manufacturing. The traditional hollow structural parts are mostly welded by forging and pressing parts, the stress concentration of the parts is obvious, and there are a large number of welding seams and machining residues, which greatly increase the weight of the vehicle. If the hollow structural parts are formed by the internal high pressure forming technology, it can not only reduce the welding seam and processing residue, reduce the weight of the vehicle, reduce the processing times, reduce the production cost, but also effectively improve the accuracy and mechanical properties of the hollow structural parts.

The tube high pressure forming technology uses a liquid medium with a certain pressure filled into the tube cavity as a punch. Under the joint action of the liquid pressure and the axial force applied by the tube end, the tube blank is deformed to fit the mold cavity and Get the part in the desired geometry. This technology has the advantages of high precision, good quality of formed parts, and the ability to form special materials and parts with complex structures. However, due to the influence of material mechanical properties and processing technology, many hollow pipes still cannot be formed by internal high pressure forming technology. Its main performance is that due to the relatively large length and diameter of the pipe material, for the area with a large expansion rate of the workpiece, the expansion rate refers to the change rate from the original pipe circumference to the maximum cross-sectional circumference of the part. This parameter is a measure of the difficulty of liquid-filled forming of the pipe. Important indicators, the punches at both ends cannot be fed in time and effectively, resulting in excessive thinning rate in this area. Usually, when the length-to-diameter ratio is greater than 5 and the expansion rate is greater than 50%, general metal materials will be difficult to form; For the fillet with a small radius in the mold, if the pressure is too small during the forming process, it will be difficult for the tube material to fit it completely; if the pressure is too high, the tube material can be filmed, but it is easy to cause the wall thickness distribution of the formed part Uneven, local wall thickness is excessively thinned, or even cracked.

Contents of the invention

In order to solve the above problems, the object of the present invention is to design a bidirectional pressurized pipe liquid-filled forming method, which can effectively increase the liquid-filled forming limit of pipe fittings and improve the forming accuracy of parts. The invention provides a two-way pressurized pipe liquid-filled forming method based on the pipe liquid-filled forming technology. The formed parts have the characteristics of high precision, good quality of formed parts, and the ability to form special materials and parts with complex structures.

A liquid-filled forming method for a two-way pressurized pipe proposed by the present invention specifically includes the following steps:

Step 1: Select the pipe material as the blank, preform the pipe material according to the shape of the mold, and place the preformed pipe blank in the lower mold of the forming equipment.

Step 2: Clamp the upper mold and the lower mold to form a mold cavity, and adjust the positions of the left punch and the right punch at the same time, so that the axes of the left punch and the right punch coincide with the center line of the preformed tube blank, and move toward the preformed tube blank. The formed tube blank is filled with high-pressure liquid, and after the air in the preformed tube blank is discharged, the left punch and the right punch are axially fed relative to each other to seal the preformed tube blank.

Step 3: After the liquid in the preformed tube blank is completely sealed, open the vent hole of the upper mold, fill the mold cavity with high-pressure liquid from the booster hole of the lower mold, and discharge the air in the mold cavity, then close the exhaust in the upper mold The pores seal the membrane cavity.

Step 4: Adjust the internal and external pressure of the pre-formed tube blank through the overflow valve and high-pressure source, and start forming. At the same time, the pre-formed tube blank is fed through the axial relative movement of the left punch and the right punch during the forming process. The excess liquid in the cavity overflows from the vent hole of the upper mold, and the amount of overflow is controlled by the overflow valve connected with the vent hole.

Step 5: After the preformed tube is completely formed, remove the internal and external pressure of the formed tube, and discharge the high-pressure liquid in the mold cavity.

Step 6: withdraw the left punch and right punch, open the mold, take out the formed pipe, remove the excess material of the formed pipe, and obtain the required workpiece.

The advantages of the present invention are:

(1): A two-way pressurized pipe liquid-filled forming method provided by the present invention is based on the pipe liquid-filled forming technology. The formed parts have the advantages of high precision, good quality of formed parts, and the ability to form special materials and parts with complex structures.

(2); A kind of two-way pressurized pipe liquid-filled forming method provided by the present invention adopts the method of two-way pressurization inside and outside the pipe, so the formed workpiece has a larger forming limit, higher strength and rigidity than unidirectional pressurized inner high-pressure forming. , The workpiece wall thickness is evenly distributed, the material utilization rate is high, and the surface quality of the formed parts is good.

Description of drawings

Figure 1: Schematic diagram of the structure of a device used in a bidirectional pressurized pipe liquid-filled forming method provided by the present invention;

Fig. 2: Schematic flow chart of a liquid-filled forming method for a two-way pressurized pipe provided by the present invention.

In the figure: 1-left punch; 2-upper die; 3-preformed tube blank; 4-vent hole;

5-right punch; 6-rubber sealing ring; 7-boosting hole; 8-lower die;

9-relief valve; 10-high pressure source.

Detailed ways

The present invention will be further described in detail with reference to the accompanying drawings and embodiments.

The present invention proposes a bidirectional pressurized pipe liquid-filled forming method, the equipment used in this method is a bidirectional pressurized pipe liquid-filled forming device, as shown in Figure 1, the device is refitted on the basis of the existing internal high pressure forming equipment Formed, that is, the upper mold 2 of the internal high pressure forming equipment is equipped with a vent hole 4, and the vent hole is connected with an overflow valve 9, which is used to control the flow of the exhaust gas, and a booster hole 7 is added to the lower mold 8, The sealing performance is improved by adding rubber sealing ring 6 in the upper mold 2 and the lower mold 8, so that a closed liquid chamber can be formed between the cavity formed by the upper mold and the lower mold. The liquid-filled forming method for bidirectional pressurized pipes includes the following steps, as shown in Figure 2:

Step 1: Select the pipe as the blank, preform the pipe according to the shape of the mold, and place the preformed pipe 3 in the lower mold 8 of the bidirectional pressurized pipe liquid-filled forming equipment.

Step 2: Clamp the upper mold 2 and the lower mold 8 to form a mold cavity, and adjust the positions of the left punch 1 and the right punch 5 at the same time, so that the axes of the left punch 1 and the right punch 5 are aligned with the preformed tube blank 3 The centerlines of the tubes are coincident, and the preformed tube blank 3 is filled with high-pressure liquid, and after the air in the preformed tube blank 3 is discharged, the left punch 1 and the right punch 5 are axially fed relative to each other (the direction in which the relative distance decreases feeding), the preformed tube blank 3 is sealed.

Step 3: After the liquid in the preformed tube blank 3 is completely sealed, open the vent hole 4 of the upper mold 2, fill the mold cavity with high-pressure liquid from the booster hole 7 of the lower mold 8, and discharge the air in the mold cavity , close the vent hole 4 of the upper mold 2 to seal the membrane cavity.

Step 4: Adjust the internal and external pressure of the preformed tube blank 3 through the overflow valve 9 and the high pressure source 10, and start forming. At the same time, the preformed tube blank is moved through the axial relative movement of the left punch 1 and the right punch 5 during the forming process. 3. Carry out feeding, the excess liquid in the mold cavity overflows from the vent hole 4 of the upper mold 2, and the amount of overflow is controlled by the overflow valve 9 connected with the vent hole 4.

Step 5: After the preformed tube blank 3 is completely formed, the required pipe fittings are formed, the internal and external pressure of the formed pipe fittings is removed, and the high-pressure liquid in the mold cavity is discharged.

Step 6: Exit the left punch 1 and the right punch 5, open the mold, take out the formed pipe, use mechanical processing and other methods to remove the excess material of the formed pipe, and then the required workpiece can be obtained.

In the above-mentioned two-way pressurized pipe liquid-filled forming method, in order to improve the plasticity and forming limit of the material, the high-pressure liquid medium filled inside and outside the preformed pipe blank 3 can be properly heated.

Claims (3)

1. A two-way pressurized pipe liquid-filled forming method, characterized in that: comprising the following steps: Step 1: Select the pipe as the blank, preform the pipe according to the shape of the mold, and place the preformed pipe in the lower mold of the forming equipment; Step 2: Clamp the upper mold and the lower mold to form a mold cavity, and adjust the positions of the left punch and the right punch at the same time, so that the axes of the left punch and the right punch coincide with the center line of the preformed tube blank, and move toward the preformed tube blank. The formed tube blank is filled with high-pressure liquid, and after the air in the preformed tube blank is discharged, the left punch and the right punch are axially fed relative to each other to seal the preformed tube blank; Step 3: After the liquid in the preformed tube blank is completely sealed, open the vent hole of the upper mold, fill the mold cavity with high-pressure liquid from the booster hole of the lower mold, and discharge the air in the mold cavity, then close the exhaust in the upper mold The hole seals the membrane cavity; Step 4: Adjust the internal and external pressure of the pre-formed tube blank through the overflow valve and high-pressure source, and start forming. At the same time, the pre-formed tube blank is fed through the axial relative movement of the left punch and the right punch during the forming process. The excess liquid in the cavity overflows from the vent hole of the upper mold, and the amount of overflow is controlled by the overflow valve connected with the vent hole; Step 5: After the preformed tube is completely formed, remove the internal and external pressure of the formed tube, and discharge the high-pressure liquid in the mold cavity; Step 6: withdraw the left punch and right punch, open the mold, take out the formed pipe, remove the excess material of the formed pipe, and obtain the required workpiece. 2. The liquid-filled forming method for two-way pressurized pipes according to claim 1, characterized in that: the forming equipment in the first step is specifically: the upper mold of the internal high pressure forming equipment is provided with vent holes , a pressurization hole is arranged on the lower mold, an overflow valve is connected to the exhaust hole, and a rubber sealing ring is arranged in the upper mold and the lower mold, so that the mold cavity formed by the upper mold and the lower mold is a closed liquid chamber. 3 . The liquid-filled forming method for two-way pressurized pipes according to claim 1 , wherein the high-pressure liquid in step 2 and the high-pressure liquid in step 3 are heated high-pressure liquids. 4 .

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