JP6619636B2 - Hot press equipment - Google Patents

Description

The present invention relates to a hot press equipment which can perform quenching due also uniform cooling if there are variations in the tolerances in the thickness of the workpiece.

  In recent years, high-strength steel sheets and high-tensile steel sheets have been actively used in vehicles such as automobiles from the viewpoint of weight reduction and collision safety improvement. However, since press formability is reduced with the increase in strength of the steel sheet and complicated shape forming cannot be easily performed, a press forming method called hot press (hot stamp) has recently been adopted.

  In this hot press (hot stamp) molding, the material to be processed (steel plate material) is heated to an austenite region of about 900 ° C., and is pressed while being cooled by contact between the material to be processed and a mold. A molded product that has been quenched is formed.

  In this way, in hot press molding, the workpiece is cooled and quenched by pressing it against the mold, so heat transfer is performed when a gap is formed between the workpiece and the mold during processing. A trouble occurs and quenching unevenness is likely to occur. However, a dimensional tolerance is defined by the JIS standard for the plate thickness of the workpiece, and variations in the plate thickness are allowed within the specified dimensional tolerance range.

  7 is a cross-sectional hat having a top surface Su, a vertical wall portion Ss continuous on both sides thereof, and a flange portion Sf formed at the lower end of the vertical wall portion Ss by hot pressing a workpiece W as shown in FIG. When forming a molded product S having a shape, a workpiece W that is heated to a predetermined temperature is inserted between an upper die (die) 101 and a lower die (punch) 102 as shown in FIG. Next, as shown in FIG. 5A, the upper mold 101 and the lower mold 102 are pressed and cooled at a predetermined cooling rate to perform a quenching process.

  A dimensional tolerance is set for the thickness t of the workpiece W. Therefore, the thickness t varies within the dimensional tolerance for each production lot. Therefore, in order to ensure a predetermined cooling rate in hot press molding, the distance between the molding surfaces of the upper die and the lower die at the time of press working is set for each production lot in accordance with the plate thickness t of the workpiece W. It needs to be adjusted.

  However, since it is difficult to adjust the distance between the molding surfaces of the upper mold and the lower mold in accordance with the variation in the thickness t of the workpiece W, for example, in Patent Document 1 (WO2013 / 005318) When forming workpieces with a cross-sectional hat shape by hot press molding the workpiece with the upper mold and the lower mold, a bead is formed on the upper molding surface of the lower mold and the upper mold to increase the contact area. By doing so, a technique for solving the lack of cooling caused by the variation in the plate thickness within the tolerance is disclosed.

WO2013 / 005318

  By the way, assuming that the molding surfaces of the upper die and the lower die are designed based on the workpiece W having the reference plate thickness, when the plate thickness t of the workpiece W is manufactured with a lower tolerance, FIG. As shown in FIG. 8B, a gap C is formed between the portion that becomes the vertical wall portion Ss of the molded product S and the molding surface of the upper mold 101 (or the lower mold 102).

  On the other hand, when the workpiece W is manufactured with a plate thickness t with an upper limit of tolerance, the upper die 101 does not reach the bottom dead center, as shown in FIG. A gap C is formed between the portion to be formed and the molding surface of the upper mold 101, and the gap h between the molding surfaces provided on the horizontal lower surfaces of both molds 101 and 102 is a plate of the molded product S. It becomes wider than the thickness t.

  As a result, in the technique disclosed in the above-described document, when the plate thickness t of the workpiece W is the tolerance lower limit, the corrugated portion is formed by a bead on the molding surface of the horizontal upper surface of the workpiece W so that the horizontal upper surface is formed. Insufficient cooling of the portion is resolved, but as shown in FIG. 8B, the gap C is formed on the surface of the vertical wall portion Ss, so that insufficient cooling is likely to occur.

  On the other hand, when the plate thickness t of the workpiece W is the upper limit of the tolerance, a gap C is formed between the portion to be the upper surface portion Su of the molded product S and the molding surface of the upper mold 101, and therefore the horizontal upper surface. However, it becomes difficult to form a waveform by a bead. Further, since the upper mold 101 does not reach the bottom dead center, the gap h between the molding surfaces on the horizontal lower surfaces provided in both molds 101 and 102 is wider than the plate thickness t, and the bending defect is not formed in the portion that becomes the flange portion Sf. Occurs. In addition, since the portion that becomes the flange portion Sf does not contact the molding surfaces of both molds 101 and 102, a sufficient cooling rate cannot be ensured, and there is a problem that uneven quenching occurs.

In view of the above circumstances, the present invention does not cause molding defects and insufficient cooling even if the thickness of the workpiece varies within the dimensional tolerance, and can be quenched at a sufficient cooling rate. an object of the present invention is to provide a hot press equipment which can improve the quality of the goods.

This onset Ming, and a freely movable mold moves toward the fixed mold and the solid fixed direction, the fixed mold intersects the movement direction of the first receiving surface and a movable-type directed against the moving direction of the movable mold In a hot press apparatus that includes a side wall surface, presses by pressing a workpiece heated to a predetermined temperature between the movable mold and the fixed mold, and performs quenching while maintaining a narrow pressure state. The movable mold includes a press pad that presses the workpiece against the first receiving surface of the fixed mold from a direction parallel to the first receiving surface, and a fixed pad that is disposed on a side of the press pad. A die having a first die portion that presses the workpiece against the side wall surface of the mold from a direction parallel to the side wall surface via a cam mechanism, and the cam mechanism is a cam slide for fixing the die. And a cam driver disposed on a side of the fixed mold, A sliding surface is formed by sliding the first die portion parallel to the direction of the side wall surface of the fixed mold by sliding on the opposing surfaces of the slide and the cam driver. A constant pressure holding source that absorbs variation in the thickness of the workpiece by elastic deformation when a reaction force of a certain value or more acts from the die side pressing the material against the side wall surface through the sliding surface. It is installed .

  According to the present invention, when hot pressing a workpiece, the movable mold is divided into a press pad and a die, and the workpiece is individually separated from the parallel receiving direction and the side wall surface of the fixed mold. Therefore, even if there is a variation in the plate thickness of the workpiece within the dimensional tolerance, the workpiece can be clamped between the fixed mold and the movable mold without any gaps, resulting in poor molding and insufficient cooling. It does not occur and can be quenched at a sufficient cooling rate. As a result, the quality of the molded product can be further improved.

Schematic diagram of hot press machine in standby state Schematic of hot press machine with upper die in the middle of lowering The bending process of bending the workpiece with the reference plate thickness is shown. (A) is the left half of the state where the work pad is pressing the workpiece against the horizontal upper surface of the lower mold, and (b) is the lowering of the cam die. The left half view of the state where the side wall surface of the workpiece is bent by the above, (c) is the left half view of the state where the descending cam die slides to the lower mold side by the reaction force of the cam driver. (D) is a left half view of a state in which the lowering cam die bends and forms the flange portion of the workpiece by the reaction force of the cam driver; ) Is the left half of the state where the cam die has reached bottom dead center, and (f) is the left half of the state just before the cam die has risen after reaching bottom dead center. (B) is a left half view of a state in which the lowering cam die bends and forms the flange portion of the workpiece by the reaction force of the cam driver; (E) is the left half view of the cam die reaching bottom dead center (B) is a left half view of a state in which the lowering cam die bends and forms the flange portion of the workpiece by the reaction force of the cam driver; (E) is the left half view of the cam die reaching bottom dead center Partial perspective view of workpiece and molded product formed by machining this workpiece A conventional example is shown, in which (a) is a cross-sectional view of an upper die and a lower die for bending and forming a workpiece having a standard plate thickness, and (b) an upper die and a lower for bending and forming a workpiece having a plate thickness with a lower tolerance limit. Cross-sectional view of mold, (c) Cross-sectional view of upper and lower molds for bending a workpiece having a plate thickness with an upper limit of tolerance

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIGS. 3 to 6, only the left half is shown for convenience, and the right half is a target shape and is omitted.

  A hot press apparatus 1 shown in FIG. 1 forms a hat-shaped molded product S as shown in FIG. 7 by hot pressing a work piece (workpiece) such as a steel plate formed in a predetermined size. A lower die 5 described later and an upper die unit 6 corresponding to the lower die 5 are arranged long from the front side to the back side.

  In this hot press apparatus 1, a pair of columns (not shown) are erected in the front-rear direction of the paper surface of the base 2, and the ram 3 is mounted so as to be movable up and down between guides provided on the opposing surfaces of the columns. ing. Further, a beam portion (not shown) is installed on the upper surface of the pair of opposed columns, and lifting means (not shown) for raising and lowering the ram 3 is fixed to the beam portion. On the other hand, a bolster 4 is fixed on the base 2, and a fixed lower die (punch) 5 is fixed to the bolster 4 so as to be exchangeable, and so as to surround the lower die 5. An upper mold unit 6 is provided.

  The lower mold 5 is a mold that regulates the inner surface when the workpiece W is bent and formed, and a cooling water circulation passage 5a for circulating cooling water for cooling the workpiece W at a predetermined speed is formed on the molding surface. Is formed along a predetermined line. Further, the lower mold 5 has a horizontal upper surface 5b as a first receiving surface directed in the moving direction of the movable mold, which will be described later, as a molding surface, and a skirt spreads from the horizontal upper surface 5b to the side intersecting the moving direction of the movable mold. A side wall surface 5c having a predetermined inclination is formed, and a horizontal lower surface 5d is formed as a second receiving surface that extends outward continuously from the lower end edge of the side wall surface 5c.

  On the other hand, the upper die unit 6 has a hat shape in cross section as shown in FIG. 7 by pressing the workpiece W set on the horizontal upper surface 5b of the lower die 5 against the molding surfaces 5b to 5d of the lower die 5. A movable mold that molds the molded product S and is movable up and down with respect to the lower mold 5 is divided into divided presser pads 7 and cam dies 8. The presser pad 7 presses the workpiece W from a direction parallel to the horizontal upper surface 5b of the lower mold 5, and a cooling water circulation passage for circulating cooling water for cooling the workpiece W at a predetermined speed inside. 7b is formed in a predetermined manner along the molding surface. The cam die 8 is formed by bending the workpiece W and pressing the workpiece W from a direction parallel to the side wall surface 5c and the horizontal lower surface 5d of the lower mold 5, A cooling water circulation passage 8d for circulating cooling water for cooling the material W at a predetermined speed is formed in a predetermined manner along the molding surface.

  The upper end of the presser pad 7 is fixed to the pad holder 7 a, and the pad holder 7 a is inserted through the support sleeve 9. Further, the upper end of the support sleeve 9 is supported via the die holder 11 with respect to the upper mold holder 10 fixed to the bottom surface of the ram 3. A pad constant pressure holding source 12 such as a gas spring, a hydraulic spring, or a coil spring is interposed between the upper end of the pad holder 7a inserted into the support sleeve 9 and the die holder 11.

  Further, the die holder 11 is fixed to the upper mold holder 10 fixed to the bottom surface of the ram 3. Further, the cam die 8 is opposed to both sides sandwiching the presser pad 7, and the work material W is placed between the side wall surface 5c of the lower mold 5 and the horizontal lower surface 5d, and both surfaces 5c, 5d. A molding surface to be pressed against the bent portion is formed. The molding surface includes a side wall die portion 8a as a first die portion, a horizontal die portion 8b as a second die portion, and an edge portion 8c formed between both die portions 8a and 8b.

  The back surface of the cam die 8 is fixed to the cam slide 13. Further, the upper surface of the cam slide 13 is supported on the lower end of the cam support rod 15 via a slide rail 14 that is allowed to slide in a direction facing and separating from each other. Further, the upper end of the cam support rod 15 is suspended from the upper mold holder 10 via a cam slide 16 such as a rubber spring.

  On the other hand, cam drivers 17 are disposed on both sides of the lower die 5 of the bolster 4, and the back surface thereof is supported by a cam driver constant pressure holding source 18. Further, the back surface of the cam driver constant pressure holding source 18 is fixed to the bolster 4 via an L-shaped bracket 19. The bottom surface of the cam driver 17 is slidably supported by the bolster 4.

  A cam surface 17a as a sliding surface is formed on the upper surface of the cam driver 17, and a cam receiving surface 13a is formed as a sliding surface in sliding contact with the cam surface 17a on the bottom surface of the cam slide 13. When the cam slide 13 descends from above and the cam receiving surface 13a is pressed against the cam surface 17a of the cam driver 17, it tries to slide in the direction of the lower mold 5 along the inclination of the cam surface 17a. In the cam slide 13, when the cam receiving surface 13a slides on the cam surface 17a, the side wall die portion 8a and the horizontal die portion 8b of the cam die 8 are parallel to the side wall surface 5c and the horizontal lower surface 5d of the lower die 5. And is set to move in the horizontal direction while being supported by the slide rail 14.

  The cam slide 13 and the cam driver 17 constitute a cam mechanism that moves the cam die 8 toward the lower die 5. Further, since the cam slide 13 is supported by the cam support rod 15 via the slide rail 14, the cam slide 13 is allowed to move in the direction of approaching and separating from the lower mold 5 with a reaction force greater than a predetermined value.

  Next, an effect | action at the time of shape | molding the molded article S using the hot press apparatus 1 by such a structure is demonstrated.

  When the hot press apparatus 1 is in the standby state shown in FIG. 1, the part to be the upper surface portion Su of the workpiece W heated to a predetermined temperature is positioned in a predetermined position on the horizontal upper surface 5 b of the lower die (punch) 5. set. Thereafter, the ram 3 of the hot press apparatus 1 starts to descend, and as shown in FIG. 2, first, the press pad 7 suspended from the lower surface of the ram 3 moves the workpiece W onto the lower die (punch) 5. It presses on the horizontal upper surface 5b from a parallel direction.

  A pad holder 7 a for fixing the upper end of the presser pad 7 is inserted into the support sleeve 9 and connected to the pad constant pressure holding source 12. Accordingly, when the ram 3 is further lowered, the pad holder 7 a relatively compresses the pad constant pressure holding source 12, and the press pad 7 presses the workpiece W against the horizontal upper surface 5 b of the lower mold 5 by the repulsive force.

  A pair of cam dies 8 are disposed opposite to each other on both sides of the presser pad 7, and the upper surface of the cam slide 13 to which the back surface of the cam die 8 is fixed is fixed to the lower end of the cam support rod 15. The slide rail 14 is supported. Further, the cam support rod 15 is suspended from the upper mold holder 10 via a cam slide constant pressure holding source 16.

  Therefore, when the ram 3 is further lowered, as shown in FIG. 3A, the edge portion 8c between the side wall die portion 8a and the horizontal die portion 8b formed on the pair of opposed cam dies 8 is pressed against the press pad 7. The workpiece W is in contact with both sides of the workpiece W which is positioned and fixed, and presses the workpiece W downward. Then, as shown in FIG. 2B, both side portions that become the vertical wall portion Ss as the side wall portion of the workpiece W are bent toward the side wall surface 5 c side of the lower mold 5. When the workpiece W is bent, since the workpiece W is fixed in a state of being positioned by the presser pad 7, the workpiece W is pressed using a clamper or the like during the bending process. Therefore, the structure of the hot press apparatus 1 can be simplified.

  Thereafter, when the ram 3 is further lowered, the cam receiving surface 13a formed on the bottom surface of the cam slide 13 comes into contact with the cam surface 17a formed on the top surface of the cam driver 17, as shown in FIG. . The bottom surface of the cam driver 17 is slidably supported on the bolster 4, and a cam driver constant pressure holding source 18 fixed to the back surface is fixed to the bolster 4 via an L-shaped bracket 19. . When the cam receiving surface 13a of the cam slide 13 is pressed against the cam surface 17a of the cam driver 17 as the ram 3 descends, the cam receiving surface 13a of the cam slide 13 slides along the cam surface 17a. Then, the side wall die portion 8b and the horizontal die portion 8b of the cam die 8 are close to each other in a direction parallel to the side wall surface 5c and the horizontal lower surface 5d of the lower mold 5, and as shown in FIG. The edge portion 8 c formed on the cam die 8 presses the end portion of the workpiece W toward the lower mold 5.

  Thereafter, as the cam slide 13 moves in the lower die 5 direction, the side wall die portion 8 a of the cam die 8 presses the workpiece W from a direction parallel to the side wall surface 5 c of the lower die 5. Further, the portion where the horizontal die portion 8 b becomes the flange portion Sf of the workpiece W is pressed from a direction parallel to the horizontal lower surface 5 d of the lower die 5. Further, the edge portion 8c is pressed against the bent portion between the side wall surface 5c and the horizontal die portion 8b.

  Then, the workpiece W is bent along the molding surfaces of the lower die 5 and the cam die 8, and the molding surfaces 8 a to 8 c of the cam die 8 form the workpiece W as shown in FIG. The lower mold 5 is pressed against the molding surfaces 5b, 5c through the thickness of the workpiece W. When the reaction force at that time exceeds a certain value, the cam receiving surface 13a of the cam slide 13 presses the cam surface 17a of the cam driver 17, and the cam driver 17 is moved from the position indicated by the one-dot chain line in FIG. Against the urging force of the holding source 18, the holding source 18 is moved back to the position indicated by the solid line (movement distance L 1).

  Then, until the ram 3 reaches the bottom dead center, the cam slide constant pressure holding source 16 is compressed and deformed to absorb the stroke of the ram 3, and the repulsive force generated in the cam slide constant pressure holding source 16 at that time causes the cam die 8 presses the workpiece W against the lower mold 5 with a constant pressure. And the state which clamped the workpiece W with the lower mold | type 5 and the upper mold | type unit 6 is hold | maintained. Cooling water circulation passages 5a, 7b and 8d formed in the lower die 5, the presser pad 7 and the cam die 8 are constantly circulated and supplied with a predetermined flow rate of cooling water, so that the workpiece W is sufficiently cooled. The molded product S, which is quenched at a speed and the upper surface portion Su, the vertical wall portion Ss, and the flange portion Sf are bent to a predetermined shape, is completed.

  Thereafter, in order to take out the molded product S, the ram 3 is raised to the standby position. In the process in which the ram 3 rises from the bottom dead center, the repulsive force of the cam slide constant pressure holding source 16 that presses the cam driver 17 via the cam slide 13 is gradually weakened, so the cam driver 17 holds the cam driver constant pressure. With the pressing force of the source 18, the initial position shown by the alternate long and short dash line in FIG. Then, the cam surface 17 a formed on the cam driver 17 pushes up the cam receiving surface 13 a of the cam slide 13. As a result, the cam slide 13 is moved obliquely upward along the inclination of the cam surface 17a while being supported by the slide rail 14, and the initial position shown in FIG. 4 (f), that is, one point in FIG. 4 (d). It returns to the position indicated by the chain line.

  When the plate thickness t of the workpiece W described above is set to the reference plate thickness t ± 0, and the workpiece W having a thickness less than the tolerance is hot-pressed, as shown in FIG. 4 (d), the cam receiving surface 13a of the cam slide 13 slides along the cam surface 17a of the cam driver 17 in the direction of the lower die 5 as the ram 3 is lowered, and the cam die 8 is moved. The workpiece W is pressed in the direction of the lower mold 5.

  Thereafter, as shown in FIG. 5 (e), the cam die 8 presses the workpiece W against the lower die 5 as the ram 3 descends. When the reaction force at that time exceeds a certain value, the cam driver 17 is pushed away by the movement distance L2, and the error when the plate thickness of the workpiece W is thinner than the reference plate thickness t ± 0 is automatically detected. To be absorbed.

  On the other hand, when the workpiece W to be hot-pressed is thicker than the reference plate thickness t ± 0, as shown in FIG. It slides in the direction of the lower mold 5 along 17a, and the cam die 8 presses the workpiece W in the direction of the lower mold 5. Thereafter, as shown in FIG. 6 (e), when the cam die 8 presses the workpiece W against the lower mold 5 and the reaction force at that time exceeds a certain value, the cam driver 17 slides by a distance L3, The error when the thickness of the workpiece W is thicker than the reference thickness t ± 0 is automatically absorbed.

  Thus, in this embodiment, when the molding surfaces 8a to 8c of the cam die 8 press the workpiece W against the lower mold 5, the portions that become the vertical wall portion Ss and the flange portion Sf of the workpiece W are Since the side wall surface 5c and the horizontal lower surface 5d of the mold 5 are pressed close to each other in a parallel direction, the error in the thickness t of the workpiece W is caused by the advance and retreat of the molding surfaces 8a to 8c of the cam die 8. Automatically absorbed by. Of course, the presser pad 7 that presses the workpiece W against the horizontal upper surface 5b of the lower die 5 also descends in parallel with the horizontal upper surface 5b, so that an error within the tolerance of the thickness t of the workpiece W is automatically absorbed. Is done.

  As a result, according to the hot press apparatus 1 of the present embodiment, the workpiece W can be separated between the lower die 5 and the upper die unit 6 even if the thickness t of the workpiece W varies within the dimensional tolerance. The pressure can be narrowed without a gap, molding defects and insufficient cooling do not occur, quenching can be performed at a sufficient cooling rate, and the quality of the molded product S can be further improved.

  In the above description, the upper mold unit 6 has been described as absorbing the error within the tolerance of the thickness t of the workpiece W. However, according to the present invention, the thickness t of the workpiece W is , 0.8 [mm], 1.6 [mm], 2.3 [mm], 3.2 [mm], the molded product S based on the inner surface formed by the molding surfaces 5b to 5d of the lower mold 5 Hot press molding can be performed without replacing the mold unit 6.

  Further, the shape of the molded product S is not limited to the cross-sectional hat shape, as long as it has a top surface portion Su that is pressed by the presser pad 7 and a vertical wall portion Ss that is bent by the cam die 8, and is a groove shape, Z shape, or L shape. It may be.

1 ... Hot press device,
2 ... Base,
3 ... Lamb,
4 ... Bolster,
5 ... Lower mold,
5a, 7b, 8d ... cooling water circulation passage,
5b ... horizontal top surface,
5c ... side wall surface,
5d ... Horizontal bottom surface,
6 ... Upper mold unit,
7 ... Presser pad
7a ... Pad holder 8 ... Cam die,
8a ... side wall die part,
8b ... Horizontal die part,
8c ... edge part,
9: Support sleeve,
10: Upper mold holder,
11 ... Die holder,
12 ... Pad constant pressure holding source,
13 ... Cam slide,
13a ... cam receiving surface,
14 ... slide rail,
15 ... Cam support rod,
16 ... Cam slide constant pressure holding source,
17 ... Cam driver,
17a ... cam surface,
18 ... Cam driver constant pressure holding source,
19 ... L bracket,
101 ... Upper mold,
102 ... lower mold,
C: void part,
h ... Gap,
S: Molded product,
Sf: Flange part,
Ss ... side wall,
Su: upper surface,
t ... Thickness W ... Work material

Claims (3)

A fixed mold and a movable mold movable in the fixed mold direction;
The fixed mold has a first receiving surface oriented in the moving direction of the movable mold and a side wall surface intersecting the moving direction of the movable mold;
In a hot press apparatus for performing press working by sandwiching a workpiece heated to a predetermined temperature between the movable mold and the fixed mold and performing quenching while maintaining a narrow pressure state,
The movable type is
A presser pad for pressing the workpiece from a direction parallel to the first receiving surface against the first receiving surface of the fixed mold;
A die having a first die portion disposed on a side of the press pad and pressing the workpiece against the side wall surface of the fixed mold from a direction parallel to the side wall surface via a cam mechanism; ,
The cam mechanism is
A cam slide for fixing the die;
A cam driver arranged on the side of the fixed mold;
Have
A sliding surface is formed which slides on the opposing surfaces of the cam slide and the cam driver to move the first die portion in parallel to the side wall surface direction of the fixed mold,
Further, when a reaction force of a certain value or more acts on the cam driver from the die side that presses the workpiece against the side wall surface, the elastic force is deformed and the thickness of the workpiece is reduced. A hot press apparatus characterized in that a constant pressure holding source that absorbs variations is provided continuously . The fixed mold has a second receiving surface that is continuous with the side wall surface on the side opposite to the first receiving surface and extends outward from the side wall surface;
Hot press of claim 1 Symbol mounting, characterized in that the second die portion for pressing the workpiece from a direction parallel to said second receiving surface to said second receiving surface to said die is provided apparatus. The die according to claim 1 or 2 SL placing the hot press device, characterized in that it is arranged on both sides of the pressing pad.

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