CN105149411A - Hydraulic forming device and method for steel pipe material - Google Patents

Abstract

The invention discloses a hydraulic forming device and method for a steel pipe material. The hydraulic forming device comprises an upper die and a lower die. Movable inserts are embedded in the two ends of the upper die, and elastic elements are installed at the bottoms of the movable inserts. The upper die and the movable insert pressed to a limit position form an upper half part cavity for a part to be formed, and the lower die is provided with a lower half part cavity. By means of the hydraulic forming device and method for the steel pipe material, deformation of the part in the die assembly period is avoided, and therefore the risks of defects of the undercut and size of the part are eliminated. A feasible scheme is provided for hydraulic formation of the steel pipe material. Application of the high-strength hydraulic formation process in the part of an automobile body is further promoted. The requirements for energy conservation and emission reduction are met. The strength of the part of the automobile body is further improved, and improvement of the safety of an automobile is greatly facilitated.

Description

A kind of hydraulic forming device of steel tubing and method

Technical field

The present invention relates to tube forming field, be specifically related to a kind of hydraulic forming device and method of steel tubing, particularly a kind of hydraulic forming device for high strength steel tubing and method.

Background technology

In recent years, in order to pursue higher performance and fuel economy, need the material using more high strength (tensile strength 1000MPa or higher) when developing bodywork parts, to reduce material weight under the prerequisite of proof strength.But traditional shaped by fluid pressure method is applicable to low-intensity steel (tensile strength <600MPa).The material behavior of high strength possesses larger elastic deformation area, and part resilience after shaping has a strong impact on precision and the stability of exterior surface dimension.The present invention is devoted to be optimized conventional hydraulic molding process and to improve, and realizes the stable hydraulic of high-strength material pipe shaping.

General, when shaped by fluid pressure, a band straight or not straight longitudinal axis pipeline section by receiving the effect of internal pressure Pi and axial force F a and shaping simultaneously.Generally plain hollow shaft-like work is processed with the method shown in Fig. 2, Fig. 3 and Fig. 4.Pipe is placed into counterdie die cavity, and mould closes (Fig. 2); Fa sealing force is applied to pipe two ends and pipe is expanded and die cavity of fitting (Fig. 3) to being filled with high pressure in pipe; Open sealing, release pressure also takes out pipe (Fig. 4).

There is following shortcoming in aforementioned general technology:

1) for high-strength material pipe, because material percentage elongation is less, pipe must control within 3% usually to the expansion rate of finished product, means that the external diameter of pipe is large as far as possible.Therefore in the matched moulds process of previous process, easily there is part undercut (Fig. 6), mold damage and part.

2) as previously mentioned, pipe external diameter for high-strength material is large as far as possible, and pipe does not have interior pressure in matched moulds process, (Fig. 7) is easily caved in by tube wall after mold cavity extruding, the part that major part is caved in all has exceeded yield strength, and material there occurs permanent deformation and creates flow harden (also known as work hardening).Concave face cannot be repaired expansion by small expansion amount in follow-up Plenum Process completely, causes final finished piece surface still to there is the dimensional discrepancy (Fig. 8 and Fig. 9) of a small amount of depression.

Summary of the invention

The object of this invention is to provide a kind of shaped by fluid pressure method of high strength steel tubing, mould and tubing generation undercut when avoiding on the one hand matched moulds, another aspect can improve accessory size quality.

For achieving the above object, the technical scheme that the present invention takes is:

A kind of hydraulic forming device of steel tubing, comprise upper die and lower die, the two ends of patrix are embedded with the loose plug that bottom is provided with flexible member, and patrix forms the first half die cavity of part to be formed with the loose plug being depressed into extreme position, and described counterdie has the latter half die cavity.

Described flexible member is including but not limited to the universal standard such as helical spring and nitrogen spring part.

By said apparatus, the present invention in advance to pipe pressurising before matched moulds, thus can obtain a kind of shaped by fluid pressure method of new steel tubing, and the method comprises the following steps:

(1) under die cavity is in open mode, pipe is put into the latter half die cavity;

(2) patrix is descending, and when loose plug contact pipe, flexible member is compressed and provides required contact force to make pipe compacted; Start to be filled with fluid to apply pressure to pipe inside in this stage, pressure progressively increases along with the descending of patrix;

(3) loose plug continues to come downwards to and pushes down pipe completely and contact counterdie; In this process, because pipe exists interior pressure, so can not be crushed and undercut occurs, the damage of mould and part is avoided;

(4) patrix continuation is descending, and flexible member is fully compressed, until patrix contact counterdie, mold cavity is completely closed, locking mould, and continues to increase interior pressure to part type region feature by completely shaping;

(5) release pressure, patrix is up opens die cavity, takes out part.

This invention avoids the part deformation in matched moulds stage, thus eliminate the risk that part undercut and dimensional defects occur, shaped by fluid pressure for high strength steel provides feasible scheme, advance the application of High Strength Hydraulic moulding process in body of a motor car part further, the demand of load energy-saving and emission-reduction, and further increase the intensity of bodywork parts, have very great help for improving vehicle safety.

Accompanying drawing explanation

Fig. 1 is the structural representation of device of the present invention.

Fig. 2 is that under Normal hydraulic forming method, pipe puts into state diagram when counterdie die cavity inner mold closes.

Fig. 3 is that under Normal hydraulic forming method, pipe puts into state diagram when counterdie die cavity applies sealing force to pipe two ends and pipe is filled with to high pressure.

Fig. 4 is the state diagram of the release pressure take-off pipe period of the day from 11 p.m. to 1 a.m under Normal hydraulic forming method.

Fig. 5 is the state diagram under Normal hydraulic forming method before matched moulds.

Fig. 6 is the view of part undercut in matched moulds process under Normal hydraulic forming method.

Fig. 7 is the view that under Normal hydraulic forming method, tube wall caves in.

Fig. 8 is the view that under Normal hydraulic forming method, piece surface exists the dimensional discrepancy of a small amount of depression.

Fig. 9 is that shaped by fluid pressure method die cavity of the present invention is in opening stage schematic diagram.

Figure 10 is that shaped by fluid pressure method patrix of the present invention starts descending phase schematic diagram.

Figure 11 is shaped by fluid pressure method loose plug of the present invention contact counterdie stage schematic diagram.

Figure 12 is that shaped by fluid pressure method part type region feature of the present invention is by complete formative stage schematic diagram.

Figure 13 is that shaped by fluid pressure method of the present invention completes all process steps stage schematic diagram.

Detailed description of the invention

Present pre-ferred embodiments is provided, to describe technical scheme of the present invention in detail below in conjunction with accompanying drawing.

Figure 1 shows that the structural representation of device of the present invention, comprise patrix 1, counterdie 5, the two ends of patrix are embedded with the loose plug 3 that bottom is provided with flexible member 2, patrix forms the first half die cavity 101 of part to be formed with the loose plug being depressed into extreme position, described counterdie has the latter half die cavity 501, and pipe 4 is placed in the latter half die cavity 501.Flexible member 2 uses helical spring herein.

Said apparatus is used to carry out the method for steel tubing shaped by fluid pressure for carry out according to the following steps:

There is provided the pipe of a both ends open (not closing), this pipe cross section is circular hollow, uniform wall thickness.

1) as shown in Figure 9, the die cavity that patrix 1, loose plug 3, counterdie 5 form is in opening stage, and pipe 4 is placed into die cavity;

2) as shown in Figure 10, patrix 1 starts descending, and when loose plug 3 contacts pipe 4, flexible member 2 is compressed and provides required contact force to make pipe 4 compacted.Start to be filled with fluid to apply a part of pressure Pa to parts 4 inside in this stage, in actual production, Pa progressively slowly should increase along with the descending of patrix 1;

3) stage shown in Figure 11, loose plug 3 is pushed down pipe 4 completely and is contacted counterdie 5, in this process, because pipe 4 exists interior pressure Pa, so the undercut occurred as shown in Figure 6 that can not be crushed, avoids the damage of mould and part; Patrix 1 continues descending, flexible member 2 is fully compressed, until patrix 1 contacts counterdie 5, mold cavity is completely closed, now by driving the press of mould to lock mould, and interior pressure durations is increased to Pb, this process is shaping similar to conventional hydraulic, and part type region feature is by completely shaping (as shown in figure 12);

4) stage as shown in figure 13, complete all need operation after, earth pressure release in pipe 4, patrix 1 is up, and mold cavity is opened completely, takes out part, so far obtains required part.

More than show and describe general principle of the present invention, principal character and advantage of the present invention.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and description just illustrates principle of the present invention; the present invention also has various changes and modifications without departing from the spirit and scope of the present invention, and these changes and improvements all fall in the claimed scope of the invention.

Claims (3)

1. the hydraulic forming device of a steel tubing, it is characterized in that, comprise upper die and lower die, the two ends of patrix are embedded with the loose plug that bottom is provided with flexible member, patrix forms the first half die cavity of part to be formed with the loose plug being depressed into extreme position, and described counterdie has the latter half die cavity.

2. the hydraulic forming device of steel tubing according to claim 1, is characterized in that, described flexible member is including but not limited to helical spring and nitrogen spring.

3. a shaped by fluid pressure method for steel tubing, it is characterized in that, the method comprises the following steps:

(1) under die cavity is in open mode, pipe is put into the latter half die cavity;

(2) patrix is descending, and when loose plug contact pipe, flexible member is compressed and provides required contact force to make pipe compacted; Start to be filled with fluid to apply pressure to pipe inside in this stage, pressure progressively increases along with the descending of patrix;

(3) loose plug continues to come downwards to and pushes down pipe completely and contact counterdie;

(4) patrix continuation is descending, and flexible member is fully compressed, until patrix contact counterdie, mold cavity is completely closed, locking mould, and continues to increase interior pressure to part type region feature by completely shaping;

(5) release pressure, patrix is up opens die cavity, takes out part.