KR20100055994A - Hot forming apparatus and hot forming method - Google Patents

Abstract

PURPOSE: A hot forming apparatus and method are provided to prevent deformation caused when separating a mold product from a mold by having an effect of quenching the mold product before separated from the mold. CONSTITUTION: A hot forming apparatus comprises a lower mold(30), an upper mold, and a cooling unit(50). A work piece is put in the lower mold and then molded with the upper mold, wherein an internal space is formed in the work piece using a cam. The cooling unit supplies cooling water to the surface of the work piece.

Description

Hot Forming Apparatus and Hot Forming Method {HOT FORMING APPARATUS AND HOT FORMING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot forming apparatus for molding a product by heating above a predetermined temperature, and more particularly, to a hot forming apparatus for improving the strength of a product manufactured by a mold operation.

Although the products manufactured by the hot forming apparatus and the hot forming method are various, the present invention will be described taking as an example a torsion beam of a rear wheel suspension of an automobile.

The torsion beam of the automobile rear wheel suspension system is composed of the beam and the trailing arms on both sides of the vehicle, and is responsible for maintaining the posture by twisting the beam against the centrifugal force acting upon the vehicle's turning. Stiffness is required.

Initially, the cross section of the steel plate is bent into a “U” or “V” shape to construct a beam, and to reinforce it with a torsion bar inside, and to have torsional rigidity and bending rigidity by welding through a reinforcement plate separate from the trailing arm. It was.

The torsion beam of the above structure can be sufficiently satisfied with torsional rigidity and bending stiffness as the strength is reinforced, but it causes a significant productivity decrease due to the increased number of parts such as torsion bar and reinforcement plate and the number of assembling and welding process, and tolerance during welding process. Problems have been pointed out, such as the failure rate is very high due to the difficulty of management, and providing a cause of lowering the fuel efficiency of the vehicle due to the weight of the product.

Recently, the cylindrical pipe is press-molded so that the center part has two layers of "U" or "V" shape for torsional rigidity, and both sides are "ㅁ" for securing a wide welding surface and bending strength with the trailing arm. A beam having a cross section is used.

It is a torsion beam beam that has sufficient rigidity against torsion and bending while reducing the number of parts, as well as the number of assembly and welding processes. have.

However, in order to obtain a beam having a different cross-sectional shape for each part as described above, the productivity is lowered as the number of processes increases and the price competitiveness is lowered due to an increase in manufacturing cost. .

In the production of cross-section "U" type or "V" type products by pressure-molding cylindrical pipes, two sets of molds having different shapes of lower molds are used, or a set of molds composed of upper molds and several lower molds moving toward each other. Methods and tools are known for obtaining the finished product.

The hot forming apparatus according to the prior art has different cross-sectional shapes for different parts, such as beams of torsion beams, so that products having a variety of cross-sections in a continuous shape are produced by the conventional manufacturing apparatus and the manufacturing method as described above. Since the strength of the portion where the end or the cross-sectional shape is deformed is not improved more than a predetermined value, there is a problem that it is easily deformed or broken.

Therefore, there is a need for improvement.

An object of the present invention is to provide a hot forming apparatus and a hot forming method to improve the strength of the product produced by the mold operation.

In addition, an object of the present invention is to provide a hot forming apparatus and a hot forming method that can reduce the occurrence of defective products caused by shape deformation during molding.

In order to achieve the above object, the present invention is a lower mold is placed on the workpiece; An upper mold coupled to the lower mold to mold a work object; A cam for forming an internal space of a work object interposed between the lower mold and the upper mold; And it provides a hot forming apparatus comprising a cooling device for supplying cooling water to the work object surface.

In addition, the cooling device of the present invention, the cooling passage provided corresponding to the work object; A pump for supplying the cooling fluid to the cooling flow path; And it provides a hot forming apparatus comprising a cooling pipe connecting the cooling passage and the pump.

In addition, the cooling flow path of the present invention, a mold flow path formed in the lower mold and the upper mold; And it provides a hot forming apparatus comprising a cam flow path formed inside the cam.

The present invention also provides a hot forming apparatus, wherein a space is formed between the cam, the lower mold, and the upper mold.

In addition, the space portion of the present invention provides a hot forming apparatus, characterized in that in communication with the mold flow path.

In addition, the space portion of the present invention provides a hot forming apparatus, characterized in that in communication with the cam flow path.

In addition, the present invention seating the workpiece to the lower mold, the pressing step of performing a hot forming by combining the upper mold and the lower mold, the cam; A molding completion determination step of determining whether a set time has elapsed after the pressing step is started; And a cooling step of supplying a cooling fluid to the surface of the work object when the time set in the molding completion determination step has elapsed.

In addition, the cooling step of the present invention provides a hot forming method characterized in that the cooling fluid is supplied between the cam and the upper mold and the lower mold to contact the cooling fluid to the workpiece.

The hot forming apparatus according to the present invention is provided with a direct cooling flow path for supplying cooling water to a work object in which the hot molding is completed, so that the work object is completed to be quenched, so that the work object is quenched in the mold. There is an advantage that the strength is improved.

In addition, the hot forming method according to the present invention is provided with a cooling step of directly supplying the coolant to the surface of the workpiece to be hot-molded, so that the effect of quenching before separating the workpiece from the hot-molded work from the mold is completed is completed Deformation of the work object generated while separating the product from the mold can be suppressed to reduce the occurrence of defective products, there is an advantage that the cost required for torsion beam production is reduced by reducing the defective rate of the product.

Hereinafter, an embodiment of a hot forming apparatus and a hot forming method according to the present invention with reference to the accompanying drawings.

In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description.

In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or custom.

Therefore, the definitions of these terms should be based on the contents throughout the specification.

1 is a perspective view showing an embodiment of a hot forming apparatus according to the present invention, Figure 2 is a front sectional view showing a flow path of an embodiment of a hot forming apparatus according to the present invention, Figure 3 is an embodiment of the present invention 4 is a side sectional view showing a flow path of the hot forming apparatus according to the present invention, and FIG. 4 is an enlarged view of a portion A shown in FIG.

1 to 4, a hot forming apparatus according to an embodiment of the present invention includes a base 10, a lower mold 30 installed on the base 10, on which a work object is placed, and a base 10. When installed in a fluidly coupled to the lower mold 30, the upper mold 20 for hot forming the workpiece and the base 10 is installed to be flowable between the upper mold 20 and the lower mold 30 A cam device 40 interposed to form the internal space of the work object, and a cooling device 50 installed in the lower mold 30, the upper mold 20, and the cam 40 to cool the work object after the hot forming is finished. ).

The base 10 is installed on the bottom surface so that the lower base 12, the lower mold 30 is installed, and the upper base (100) so as to be movable in the vertical direction by the base cylinder 16, the upper mold ( And an upper base 14 on which 20 is installed.

After the workpiece is placed on the lower mold 30, the base cylinder 16 is driven to lower the upper base 14 and the upper mold 20, and the upper mold 20 and the lower mold 30 are coupled to the mold. Press work is performed.

At this time, the upper mold 20 and the lower mold 30 is heated above a predetermined temperature to hot-form the workpiece.

A heating apparatus (not shown) for heating the mold to perform a hot forming operation is well known to those skilled in the art to which the present invention pertains, and thus detailed drawings and description thereof will be omitted.

Since the base cylinder 16 is also a hydraulic cylinder that is well known to those skilled in the art, detailed drawings, descriptions, and a description of the driving method will be omitted.

In addition, since the base cylinder 16 is also a conventional hydraulic cylinder, detailed drawings and explanations and driving methods will be omitted.

The guide 32 is installed between the lower mold 30 and the upper mold 20, which is a device for allowing the upper mold 20 and the lower mold 30 to be coupled in the correct position.

In addition, the guide 32 allows the workpiece to be accurately centered when it is placed on the lower mold 30, so that the finished product can be precisely symmetrical.

The guide 32 is made of a piece of a predetermined size that is installed on the groove rim of the lower mold 30 on which the work object is seated, the side forming the guide 32 is lower by a conventional fastening member such as bolts, rivets, etc. It is coupled to the upper surface of the mold (30).

The cam 40 is installed on a pair of cam cylinders 42 installed in the horizontal direction on the upper surface of the lower base 12.

When the arm of the cam cylinder 42 protrudes, the cam 40 installed at the end of the arm is interposed between the lower mold 30 and the upper mold 20, and when the arm is inserted into the cam cylinder 42, the cam 40 is inserted. ) Is discharged from the space between the lower mold 30 and the upper mold 20.

In this configuration, when the pipe-shaped torsion beam 70 is placed on the lower mold 30 and the cam cylinder 42 is driven, the cam 40 is inserted into both ends of the torsion beam 70.

After the base cylinder 16 is driven and the upper mold 20 is lowered and coupled to the lower mold 30, the hot forming is made.

As described above, the mold apparatus for manufacturing the pipe-shaped beam by the upper mold 20, the lower mold 30, and the cam 40 can be easily carried out by those skilled in the art. The exploded perspective view showing the upper mold 20, the lower mold 30, and the cam 40 in detail because of the device will be omitted.

The cooling device 50 is formed in at least one of the lower mold 30, the upper mold 20, and the cam 40.

The cooling device 50 is provided to correspond to the work object, the cooling passage 52 for supplying the cooling fluid, the pump (not shown) for supplying the cooling fluid to the cooling passage 52, the pump and the cooling passage 52 ) And a tank (not shown) that is connected to the cooling pipe 54 by filling the cooling pipe 54 and the cooling fluid.

Here, the cooling flow path 52 is arranged so that the tissue of the torsion beam, which is a workpiece having an austenite structure in hot forming, is directly transformed into martensite tissue.

The cooling passage 52 may be disposed to correspond to the work object through the lower mold 30, the upper mold 20, or the cam 40 so as to quench the work object.

More preferably, a plurality of cooling passages 52 are disposed to penetrate the lower mold 30, the upper mold 20, or the cam 40 so as to correspond to the work object.

The cooling passage 52 includes a mold passage 52a formed inside the lower mold 30 and the upper mold 20, and a cam passage 52b formed inside the cam 40.

The cooling pipe 54 includes a mold pipe 54a connected to the upper mold 20 and the lower mold 30 from the tank, and a cam pipe 54b connected to the cam 40 from the tank.

The cooling pipe 54 is provided with a valve 56 in a pipe extending from the tank, from which the mold pipe 54a and the cam pipe 54b branch off.

Thus, when the pump is driven after the end of hot forming, the cooling fluid is supplied to the surface of the workpiece along the cooling flow path 54 formed through the lower mold 30, the upper mold 20, and the cam 40, so that the lower mold The temperature of the workpiece | work interposed between 30, the upper mold 20, and the cam 40 is rapidly cooled below predetermined temperature.

The cam 40 has a cross section of the outer end corresponding to the cam cylinder 42 in a square shape, and the cross section of the cam 40 becomes smaller toward the inner end thereof.

In addition, since the cam 40 has a 'V' shaped groove toward the inner end, the cam 40 can process the shape of the torsion beam 70.

5 is a side cross-sectional view showing a flow path of a hot forming apparatus according to another embodiment of the present invention, and FIG. 6 is a detailed view of portion B shown in FIG.

5 and 6, the hot forming apparatus according to another embodiment of the present invention as compared to the lower mold 130, the upper mold 120, the cam 140, the cooling device 150 The same thing is achieved, but the cooling device 150 has its features.

Unlike the embodiment, the cooling device 150 is characterized in that the space 110 is formed between the cam 140, the lower mold 130, the upper mold 120.

In addition, since the space 110 communicates with the mold flow path 152a and the cam flow path 152b, the cooling water introduced through the mold flow path 152a and the cam flow path 152b is supplied into the space 110 and thus the torsion beam. (70: see FIG. 2) The supply of the cooling water is made inside, and when the cooling water is filled in the space 110, the contact amount of the torsion beam 70 and the cooling water is increased to increase the cooling rate.

Thus, when the torsion beam 70 is cooled, the cooling fluid supplied along the cooling passage 152 accelerates cooling of the torsion beam 70 while directly contacting the torsion beam 70 while flowing into the space 110. .

By such a configuration and operation, the torsion beam 70 can be more easily converted into martensite tissue, so that the strength reinforcement of the torsion beam 70 can be made more effectively.

The space part 110 communicates with a cooling passage 152 formed in at least one of the lower mold 130, the upper mold 120, and the cam 140, where the lower mold 130 and the upper mold 120 are formed. An example in which the space 110 communicates with the mold flow path 152a of FIG. 3 and the cam flow path 152b of the cam 140 is illustrated in the drawings.

However, the space 110 may be in communication with only one of the mold channel 152a of the upper mold 120, the mold channel 152a of the lower mold 130, and the cam channel 152b of the cam 140. In addition, the grooves formed in each component may be molded to form a cooling flow path while being coupled to each other.

As described above, the structure of the cooling channel 152 may be easily implemented by those skilled in the art, which are aware of the technical configuration of the present invention. It will be omitted.

Looking at the operation of the hot forming method according to an embodiment of the present invention configured as described above are as follows.

7 is a flow chart showing a hot forming method according to an embodiment of the present invention, Figure 8 is a perspective view showing a torsion beam manufactured by a hot forming apparatus and a hot forming method according to an embodiment of the present invention FIG. 9 is a cross-sectional view taken along the line AA of FIG. 8, FIG. 10 is a cross-sectional view taken along the line BB shown in FIG. 8, and FIG. 11 is a cross-sectional view taken along the line CC shown in FIG. 8.

Referring to Figures 7 to 11, the hot forming method according to an embodiment of the present invention seats the workpiece, that is, the beam beam 70 to the lower mold 30, the upper mold 20 and the lower mold ( 30), the pressing step (S10) for performing hot forming by combining the cam 40, the molding completion determination step (S20) and the completion of the determination step for determining whether the set time has elapsed after the pressing step (S10) is started When the time set in S20 has elapsed, it is determined whether the temperature of the torsion beam 70 is lower than or equal to the set temperature after the cooling step S30 for supplying a cooling fluid to the surface of the torsion beam 70 and the cooling step S30. In the temperature judging step (S40) and the temperature judging step (S40), if the workpiece is less than the set temperature to separate the upper mold 20, the lower mold 30, the cam 40 to separate the torsion beam 70 It includes a separation step (S50).

The hot forming method will be described in detail below.

First, when the cam cylinder 42 is driven after the torsion beam 70 of a pipe shape metal is seated on the lower mold 30, the cam 40 is inserted into both ends of the torsion beam 70.

Thereafter, while the base cylinder 16 is driven, the upper mold 20 is coupled to the lower mold 30 so that the pressing step S10 is performed.

At this time, the upper mold 20, the lower mold 30, and the cam 40 forming the hot forming is heated to 600 ° C ~ 900 ° C to perform the hot forming.

Molding determination step (S20) is a step of measuring the time that the hot forming is in progress, it is made by a conventional time measuring device such as a timer.

When it is detected that the time set by the molding completion determination step (S20) has elapsed, the pump is driven so that the lower mold 30, the upper mold 20, and the cam 40 along the cooling pipe 54 and the cooling passage 52. The cooling step (S30) for quenching the torsion beam 70 while the cooling fluid is supplied to the surface of the torsion beam 70 through the through.

The torsion beam 70 that is quenched in this way is quenched for about 1 second to about 100 ℃ ~ 350 ℃.

The cooling step (S30) is to lower the temperature of the torsion beam 70 to a predetermined temperature or less within a set time to change the structure of the torsion beam 70 made of a metallic material from austenite tissue to martensite tissue By doing so, the strength of the torsion beam 70, which is a work object, is improved.

At this time, the cooling fluid cools the torsion beam 70 while contacting the torsion beam through the lower mold 30, the upper mold 20, and the cam 40, and is discharged to the outside of the mold through a separate outlet.

As a result, the upper mold 20, the lower mold 30, and the cam 40 are cooled, and the torsion beam 70 in contact with the upper mold 20, the lower mold 30, and the cam 40 is quenched. As the cooling fluid and the torsion beam 70 which are filled in the space between the mold 20, the lower mold 30, and the cam 40 are in contact with each other, the cooling speed is increased, thereby making the quenching work more effective.

As described above, the method of directly supplying the cooling water to the torsion beam 70 can accelerate the cooling rate compared to the method of circulating the cooling water only inside the mold to perform the cooling operation. It can be easily converted.

Temperature determination step (S40) detects the time the cooling fluid is supplied by a conventional time measuring device as in the molding completion determination step (S20), and when the set time has elapsed, the cooling step (S30) is terminated to the torsion beam 70 ) To complete the production.

Thereafter, the base cylinder 16 is driven in the reverse direction, the cam cylinder 42 is driven in the reverse direction, and the upper mold 20 and the lower mold 30 are separated, and the cams 40 are formed from both ends of the torsion beam 70. The separation step S50 is performed.

By the above-described configuration and operation, both ends 74 of the torsion beam 70 form a square shape, and the central portion 72 forms a 'V' shape in which the upper and lower surfaces are in close contact with each other, and the central portion 72 is formed. The connecting portion 76 between the end portion 74 and the end portion 74 has a torsion beam 70 formed with a 'V' shaped groove in the center of the top surface.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand.

In addition, the torsion beam for automobile rear suspension has been described as an example, but this is merely exemplary, and the hot forming manufacturing method of the present invention may also be used for torsion beams used in products other than torsion beams used in automobiles.

Therefore, the true technical protection scope of the present invention will be defined by the claims below.

1 is a perspective view showing an embodiment of a hot forming apparatus according to an embodiment of the present invention.

Figure 2 is a front sectional view showing a flow path of an embodiment of a hot forming apparatus according to an embodiment of the present invention.

Figure 3 is a side cross-sectional view showing a flow path of the hot forming apparatus according to an embodiment of the present invention.

4 is an enlarged view of a portion A shown in FIG. 3.

5 is a side cross-sectional view showing a flow path of a hot forming apparatus according to another embodiment of the present invention.

FIG. 6 is a detailed view of the portion B shown in FIG. 5.

7 is a flowchart illustrating a method for manufacturing hot forming according to an embodiment of the present invention.

8 is a perspective view showing a torsion beam manufactured by a hot forming apparatus and a hot forming method according to an embodiment of the present invention.

9 is a cross-sectional view taken along the line A-A shown in FIG.

FIG. 10 is a cross-sectional view taken along the line B-B shown in FIG. 8.

FIG. 11 is a cross-sectional view taken along the line C-C shown in FIG. 8.

<Explanation of symbols on main parts of the drawings>

10: base 12: lower base

14: upper base 16: base cylinder

20: upper mold 30: lower mold

32: guide 40: cam

42: cam cylinder 50: cooling device

52: cooling flow path 52a: mold flow path

52b: Cam euro 54: Cooling pipe

54a: mold pipe 54b: cam pipe

56: valve 70: torsion beam

72: center 74: end

76: connection

Claims (8)

A lower mold on which the workpiece is placed; An upper mold coupled to the lower mold to mold a work object; A cam for forming an internal space of a work object interposed between the lower mold and the upper mold; And Hot forming apparatus comprising a cooling device for supplying cooling water to the surface of the workpiece. The method of claim 1, The cooling device, A cooling passage provided corresponding to the work object; A pump for supplying the cooling fluid to the cooling flow path; And And a cooling pipe connecting the cooling flow path and the pump. The method of claim 2, The cooling passage, A mold flow path formed in the lower mold and the upper mold; And Hot forming apparatus comprising a cam flow path formed in the cam. The method of claim 3, Hot forming apparatus, characterized in that the space portion is formed between the cam and the lower mold, the upper mold. The method of claim 4, wherein And the space portion communicates with the mold flow path. The method of claim 4, wherein And the space portion communicates with the cam flow path. A pressing step of placing a work object on the lower mold and performing hot forming by combining the upper mold, the lower mold and the cam; A molding completion determination step of determining whether a set time has elapsed after the pressing step is started; And And a cooling step of supplying a cooling fluid to the surface of the workpiece when the time set in the molding completion determination step has elapsed. The method of claim 7, wherein The cooling step is a hot forming method characterized in that for supplying the cooling fluid between the cam and the upper mold and the lower mold to contact the cooling fluid to the workpiece.

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