JP5884194B2 - Press molding method and press molding apparatus - Google Patents

Description

  The present invention relates to a press molding method and apparatus for press molding a molded part having a groove portion having vertical walls on both sides.

In hot / warm press forming, in which press forming is performed by heating a metal plate material, the thickness of the molded product is partially reduced due to the shape of the molded product, which leads to cracks in the molded product. It has been considered to minimize the reduction in sheet thickness.
For example, as an example of hot pressing, in Patent Document 1, a molding surface of a mold is provided with a plurality of refrigerant discharge ports and a lubricating liquid supply port, and the deformation resistance and frictional resistance during molding are controlled to locally A hot press forming method that prevents the occurrence of breakage and scratches has been proposed.

Japanese Patent No. 4616737

In general, many automobile frame members have a hat-shaped groove-shaped cross section. In particular, a member that receives an impact force at the time of a collision called a collision member is required to have strength in the collision direction of the hat-shaped cross section. .
Side sills, bumper members, etc. are such collision members, and the vertical wall part in the hat-shaped cross section contributes to the collision strength, so there is a demand to make the vertical wall part relatively thicker than other parts. is there.

However, when a steel plate is heated and press-molded into a hat-shaped cross section with a die, the punch usually comes into contact with the portion corresponding to the bottom of the hat-shaped cross section in the blank (steel plate) first, so that the portion is cooled. As a result, the deformation resistance of the steel sheet increases.
On the other hand, the part of the blank (steel plate) that becomes the vertical wall is temporally after the part that makes contact with the mold, and the vertical wall also has a clearance between the mold and the mold. Therefore, the high temperature state is maintained and the deformation resistance during molding is small. Also, a large tension acts on the vertical wall during press molding. For this reason, the vertical wall portion has a greater thickness reduction than the bottom portion during press molding.
If the thickness of the vertical wall is reduced, the strength of this part will decrease, so in order to ensure the strength of the part, the reduction of the thickness of the relevant part is taken into account, and the thickness of the metal plate as the material Therefore, the thickness of the part other than the vertical wall also increases, and the entire part increases in weight.

  In order to solve the above problem, even if a hat-shaped groove-shaped cross-sectional member is formed by the press molding method disclosed in Patent Document 1, the technique disclosed in Patent Document 1 suppresses a reduction in plate thickness during molding. Even if we can minimize the decrease in the thickness of the vertical wall, the thickness of the vertical wall is always thinner than the thickness of the bottom. Eventually, in order to secure the strength as a part, the thickness of the entire part including the thickness of the vertical wall portion had to be increased.

  The present invention has been made to solve such a problem, and in press molding a molded part having a groove-shaped portion having vertical walls on both sides, while suppressing a decrease in the thickness of the vertical wall, the bottom plate is further provided. It is an object of the present invention to provide a press molding method and apparatus capable of reducing the thickness relative to the plate thickness of a vertical wall.

(1) In the press molding method according to the present invention, a heated plate material is press-molded into a molded part having a groove portion having vertical walls on both sides using a punch and a die that are configured to be widened. A press molding method,
A groove shape forming step of forming a groove shape so that the punch and the die do not contact with a portion corresponding to the bottom of the groove shape portion of the plate material to be formed; and a groove bottom portion formed by the groove shape forming step An elongation imparting step for imparting elongation to reduce the thickness of the bottom of the groove, and a widening step for moving the punch and the die in the widening direction to extend the groove bottom to which the elongation is imparted in the width direction. It is characterized by that.
In addition, the part corresponding to the bottom part of the groove-shaped part in the plate material to be molded includes all and part of the bottom part, and in some cases, the center part of the bottom part is preferable.

(2) Further, in the above-described (1), the elongation imparting step is formed in the groove shape forming step by a separate punch provided between the punches so as to be relatively movable separately from the punches. Further, the elongation is imparted by projecting the bottom of the groove.

(3) Moreover, the thing given in said (1) WHEREIN: The said extension provision process is shape | molded by the said groove shape formation process by the separate punch provided in the said die so that relative movement was possible separately from the said die. Further, the elongation is imparted by projecting the bottom of the groove.

(4) Moreover, the thing in any one of said (1) thru | or (3) WHEREIN: The cooling process which cools the said groove bottom part in the state which pinched | interposed the said to-be-molded board material with the metal mold | die after the said widening process is provided. It is characterized by that.

(5) A press molding apparatus according to the present invention is a press molding apparatus that press-molds a molded part having a groove portion having vertical walls on both sides by using a heated plate material.
A punch having a convex part, a die having a concave part corresponding to the convex part of the punch, and a driving device for driving at least one of the punch or the die,
The punch comprises a pair of both side punches configured to be widened, and a separate punch provided between the both side punches and moving separately from the both side punches with respect to the die,
The die includes a pair of members configured to be widened, and has a recessed groove portion in a portion corresponding to the separate punch,
A die widening means for widening the both-side punch and the die in a state where the punch and the die are at the bottom dead center is provided.

(6) In the above (5), the die is a pair of both-side dies configured to be widened, and the both-side dies provided between the both-side dies with respect to the punch. It has a separate die that moves separately,
The separate die is disposed at a position recessed from the both-side dies, so that the recessed groove portion is formed.

(7) A press molding apparatus according to the present invention is a press molding apparatus that press-molds a molded part having a groove portion having vertical walls on both sides by using a heated plate material.
A punch having a convex part, a die having a concave part corresponding to the convex part of the punch, and a driving device for driving at least one of the punch or the die,
The die comprises a pair of both-side dies that are configured to be widened, and a separate punch that is provided between the both-side dies and moves separately from the both-side dies with respect to the punch,
The punch includes a pair of members configured to be widened, and has a recessed groove portion in a portion corresponding to the separately-moving punch,
A die widening means for widening the both-side punch and the die in a state where the punch and the die are at the bottom dead center is provided.

(8) Further, in the above-described (7), the punch is a pair of both-side punches configured to be widened, and provided between the both-side punches and separate from the both-side punches with respect to the die. With a separate die that moves,
The separate die is disposed at a position recessed from the both side punches, so that the recessed groove portion is formed.

(9) Further, in any of the above (5) to (8), the die includes a roller that reduces friction with the plate member at the periphery of the recessed portion. Is.

(10) Further, in any of the above (5) to (9), the punch is provided with a roller on the shoulder portion of the convex portion to reduce friction with the plate material. Is.

(11) Further, in any of the above (5) to (10), provided with a coolant supply means for supplying a coolant for cooling the bottom of the plate material to be formed at the bottom dead center. It is characterized by that.

(12) Further, in any of the above (5) to (11), the tip surface of the separate punch is formed in an arc shape.

(13) Further, in any one of the above (5) to (12), a heating means for heating the separate punch is provided.

  In the present invention, a groove shape forming step for forming a groove shape so that the punch and the die do not come into contact with the portion corresponding to the bottom of the groove shape portion in the plate material to be formed, and the groove formed in the groove shape forming step An elongation imparting step for imparting elongation to reduce the thickness of the groove bottom portion at the bottom, and a widening step for extending the groove bottom portion to which the elongation is imparted in the width direction by moving the punch and the die in the width expanding direction. Therefore, the thickness of the bottom, which is a portion that does not require further strength, can be made relatively thin compared to the thickness of the vertical wall while suppressing the reduction in the thickness of the vertical wall. The impact strength can be increased and the weight can be reduced.

It is explanatory drawing of the principal part of the press molding apparatus which enforces the press molding method which concerns on Embodiment 1 of this invention. It is explanatory drawing of the press molding method which concerns on Embodiment 1 of this invention. It is sectional drawing of the components shape | molded by the press molding method which concerns on Embodiment 1 of this invention, Comprising: The effect of this invention is demonstrated. It is explanatory drawing about the cooling process of the press molding method which concerns on Embodiment 1 of this invention. It is a longitudinal cross-sectional view of the press molding apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing of the other aspect of the press molding apparatus shown in FIG. It is a longitudinal cross-sectional view of the press molding apparatus which concerns on Embodiment 3 of this invention, Comprising: It is explanatory drawing of the other aspect of a widening means. It is a longitudinal cross-sectional view of the press molding apparatus which concerns on Embodiment 4 of this invention, Comprising: It is explanatory drawing of the other aspect of a widening means. It is a longitudinal cross-sectional view of the press molding apparatus which concerns on Embodiment 5 of this invention. It is a longitudinal cross-sectional view of the press molding apparatus which concerns on Embodiment 6 of this invention. It is a modification of the press molding apparatus shown in FIG. It is a modification of the press molding apparatus shown in FIG. It is explanatory drawing of the evaluation method which concerns on the Example of this invention.

[Embodiment 1]
Since the press molding method according to the embodiment of the present invention is press molding using a punch and a die that are configured to be widened, before explaining the press molding method in detail, 1 will be described as an example.

  The press molding apparatus 1 has a punch 2 and a die 6 corresponding to the punch 2. Each configuration will be described in detail below.

<Punch>
The punch 2 includes a pair of both side punches 3 configured to be widened (movable in directions away from each other), and a separate punch 5 provided between the both side punches 3 so as to be movable up and down separately from the both side punches 3. Become.
The width of the punch bottom before widening is set narrower than the width of the bottom of the molded part.

The separate punch 5 is for projecting a portion corresponding to the bottom of the molded part of the plate material 11 to be formed downward at the bottom dead center of the both-side punch 3.
The separate punch 5 can move further downward than the lower end at the bottom dead center of the double-sided punch 3, and can extend the plate material 11 to be formed downward.

<Die>
The die 6 includes a pair of both-side dies 7 configured to be widened, and a separate die 9 provided between the both-side dies 7 so as to be movable up and down separately from the both-side dies 7.
The widening of the double-sided die 7 is performed so as to be the same as the widening timing and the moving distance of the double-sided punch 3. In this way, the plate material 11 can be moved in the widening direction with the both-side punch 3 and the both-side dies 7 being sandwiched.

Next, an example of a method of press molding using the press molding apparatus 1 configured as described above will be described together with the operation of the press molding apparatus 1. An example of the molding object is a hat cross-sectional component 13 (see FIG. 3) as a molded component having a groove portion.
As shown in FIG. 2, the press molding method according to the present embodiment is applied to a portion (a portion corresponding to the thin portion 15 a (see FIG. 3)) corresponding to the component bottom portion 15 of the hat cross-section component 13 in the plate material 11. A groove shape forming step for forming a groove shape so that the punch 2 and the die 6 do not come into contact with each other; an elongation applying step for applying an elongation for reducing the plate thickness of the groove bottom formed in the groove shape forming step; And a widening step of moving the punch 3 and both side dies 7 in the widening direction to stretch the groove bottom portion to which the elongation is given in the width direction.

FIG. 2A shows a state before the start of press molding. As shown in FIG. 2A, the tip of the separate punch 5 is not protruded downward from the lower end of the both-side punch 3.
The upper surface of the separate die 9 is positioned below the die bottom so as not to contact the plate material 11 to be molded. Therefore, a concave groove portion 12 is formed between the separate die 9 and the die bottom portion, and the tip of the separate punch 5 can be inserted into the concave groove portion 12.
The heated plate material 11 is placed so as to straddle the dies 7 on both sides.

<Groove shape forming process>
The groove shape forming step is a step in which the both-side punch 3 and the separate punch 5 are integrally moved downward from the state of FIG. 2A and pressed into the die 6 to form a groove shape (FIG. 2B). reference).

  Since the portion corresponding to the thin portion 15a (see FIG. 3) of the plate member 11 is formed without being in contact with the punch 2 and the die 6, it is maintained in a high temperature state, and its deformation resistance is small. Therefore, in the groove shape forming process, the material flow occurs in the portion corresponding to the thin portion 15a and the plate thickness is reduced, while the material corresponding to the component vertical wall portion 17 (see FIG. 3) is reduced. There is little flow and the plate thickness reduction is suppressed.

  In addition, you may pinch the part corresponding to the component vertical wall part 17 with the both-sides punch 3 and the both-sides die 7 by slightly widening the both-sides punch 3 in a bottom dead center (refer FIG.2 (b)). By doing so, the movement of the material in the portion corresponding to the component vertical wall portion 17 can be more reliably restricted, and the plate thickness as the component vertical wall portion 17 is ensured. Moreover, it cools by the both-sides punch 3 and the both-sides die 7, and intensity | strength is ensured by quenching. Furthermore, there is also an effect as fixing for the subsequent steps.

<Elongation imparting process>
The elongation imparting step is a step of imparting elongation to the portion by further moving only the separate punch 5 and projecting the portion corresponding to the thin portion 15a downward.
In this step, the overhanging portion 11a is formed at a portion corresponding to the thin portion 15a (see FIG. 2C). The plate thickness of the overhang portion 11a is smaller than the plate thickness before the overhang.
Since the portion corresponding to the thin portion 15a remains at a high temperature as described above, the deformation resistance is small and elongation can be imparted relatively easily.

<Wide widening process>
In the widening step, the separate punch 5 and the separate die 9 are moved upward until the height is about the same as the lower end of the double-sided punch 3, and the double-sided punch 3 and the double-sided punch 3 until the width of the component bottom 15 of the hat cross-sectional component 13 is reached. This is a step of widening the both-side dies 7 (see FIG. 2D).
The widening is performed while sandwiching a portion corresponding to the component vertical wall portion 17 at the component bottom portion 15 of the hat cross-sectional component 13.
When widening is performed, the overhanging portion 11a is stretched to become a flat surface.
In this way, the portion that was the overhanging portion 11a becomes a thin portion 15a of the component bottom portion 15 as shown in FIG.

In this state, press molding is completed when the plate material 11 is sufficiently cooled.
Note that immediately after the widening step, the portion corresponding to the component bottom 15 is still at a high temperature, so it is preferable that the portion is sufficiently cooled to have a tensile strength (cooling step). Although there are various modes as the cooling method, for example, a cooling method using cooling oil can be mentioned. As an example of such a device, as shown in FIG. 4, a cooling oil supply device 21 that supplies cooling oil, and a cooling oil that is connected to the cooling oil supply device 21 and that corresponds to the part bottom portion 15. And a cooling oil pipe 23 for injecting water.

  As described above, if press molding is performed using the press molding apparatus 1 according to the present embodiment, it is possible to suppress a reduction in the plate thickness of the component vertical wall portion 17. Further, the plate thickness of the component bottom portion 15 can be reduced as compared with the plate thickness of the component vertical wall portion 17, and as a result, the weight of the hat cross-section component 13 can be reduced.

[Embodiment 2]
Regarding the press molding apparatus 1, the detailed shape of the punch 2 and the die 6 and the explanation of a part of the configuration such as the widening means of the punch 2 and the die 6 are omitted, but the above press molding method is performed. A more specific press molding apparatus will be described below.
As shown in FIG. 5, the press molding apparatus 30 according to the present embodiment includes a punch 32 having a convex portion, a die 36 having a concave portion corresponding to the convex portion of the punch 32, and a drive for moving the punch 32 up and down. The punch 32 includes a pair of both-side punches 33 that are configured to be widened, and a separate punch 35 that is provided between the both-side punches 33 and moves separately from the both-side punches 33. 36 includes a pair of both-side dies 37 configured to be widened, and a separate die 39 provided at a portion corresponding to the separate punch 35 between the both-side dies 37 and moving separately from the both-side dies 37. Further, a die widening means 41 for widening the both-side punch 33 and both-side dies 37 in a state where the punch 32 and the die 36 are at the bottom dead center is provided.
Each configuration will be described in detail below based on FIG.

<Punch>
The punch 32 is used without being widened in the groove shape forming process, and in cooperation with the die 36, the plate member 11 is formed into a groove shape, and is widened in the widening step, and the component bottom portion 15 in the plate member 11 is formed. Extend the part corresponding to to flatten.
The width of the punch bottom before widening is set to be narrower than the width of the component bottom 15 of the molded part.

≪Both side punch≫
As shown in FIG. 5, the double-sided punch 33 is composed of a pair of left and right members, and can be widened.
In the center of the lower end of the both-side punch 33 in the width direction, a separately-moving punch installation portion 33a made of a rectangular recess is provided, and the separately-moving punch 35 can be installed.

≪Separate movement punch≫
The separate punch 35 is for projecting a portion corresponding to the component bottom 15 downward at the bottom dead center of the double-sided punch 33.
The separate punch 35 includes a pair of members that can be divided from the center, and each member is held so as to be vertically movable by a separate punch vertical movement hydraulic cylinder 45 provided on the both-side punch 33 as shown in FIG. Has been.
A plurality of separate punch vertical movement hydraulic cylinders 45 are provided along the longitudinal direction of the both-side punches 33 (perpendicular to the paper surface).

The tip surface of the separate punch 35 is formed in an arc shape. In order to uniformly reduce the plate thickness when the plate material 11 is stretched, it is preferable to reduce the friction between the tip surface of the separate punch 35 and the plate material 11.
The separate punch 35 is configured such that the lower end portion of the separate punch 35 does not protrude below the lower end of the double-sided punch 33 before the press molding is started, and is integrated with the double-sided punch 33 as it is in the groove shape forming step. Move down.
In the elongation imparting step, the plate member 11 is moved downward and protruded downward by the lower end of the separate punch 35 to form the protruding portion 11a (see FIG. 2C).
In the widening process, the die moves up to the same height as the lower end of the both-side dies 37 (see FIG. 2D). The pair of members constituting the separate punch 35 are separated in the widening direction as the double-sided punch 33 is widened.

  In addition, as shown in FIG. 5, you may provide the heater 43 as a heating means which heats the separate punch 35. As shown in FIG. By heating the separate punch 35 with the heater 43, the temperature of the plate member 11 can be extended more uniformly without locally lowering the temperature of the plate member 11 when the plate member 11 is stretched in the elongation imparting step.

<Die>
The die 36 cooperates with the punch 32 in the groove shape forming step to form the plate member 11 into a groove shape, and in the widening step, the die 36 is widened together with the punch 32 and the portion corresponding to the component bottom 15 is extended and flattened. It is for making.

≪Die on both sides≫
As shown in FIG. 5, the both-side dies 37 are configured by a pair of left and right members, and can be widened.
In the center in the width direction at the upper end of the both-side dies 37, a separate die installation portion 37a made of a rectangular recess is provided.

≪Separate die≫
The separate die 39 is for lifting the overhanging portion 11a in the widening step (see FIG. 2D) and smoothing the flattening and widening of the overhanging portion 11a. Therefore, the upper surface of the separate die 39 is flat.
As shown in FIG. 5, the separate die 39 includes a pair of members that can be divided from the center, and each member is supported by a separate die up / down cylinder 49 provided on each side die 37 so as to be vertically movable. ing.
A plurality of separately-moving die vertical movement cylinders 49 are provided along the longitudinal direction (perpendicular to the paper surface) of both-side dies 37.

Prior to the start of press molding, the upper surface of the separate die 39 is positioned lower than the bottom of the die, thereby forming the recessed groove portion 40 into which the tip of the separate punch 35 can be inserted.
In addition, since the recessed groove portion 40 is formed, the separate die 39 does not contact the plate member 11 in the groove shape forming step and the elongation imparting step, and it is possible to maintain a high temperature and easy deformation state.
In the widening step, the separate die 39 moves up to a height that is about the same as the lower end of the double-sided punch 33 to lift the overhanging portion 11a. A pair of members constituting the separate die 39 are separated in the widening direction with the widening of the both-side dies 37.

<Mold widening means>
The mold widening means 41 is for widening the double-sided punch 33 and the double-sided die 37.
As shown in FIG. 5, the mold widening means 41 includes a plurality of punch widening hydraulic cylinders 53 provided so as to extend over both side punches 33 and a plurality of die widening hydraulic pressures provided over both side dies 37. Cylinder 55 is provided, and by driving these, both side punches 33 and both side dies 37 can be widened.
The punch widening hydraulic cylinders 53 and the die widening hydraulic cylinders 55 are controlled such that the widening timing and stroke of the double-sided punch 33 and double-sided die 37 are the same. By doing so, the both-side punch 33 and the both-side dies 37 can be widened while sandwiching the component vertical wall portion 17.

<Drive device>
The drive device 31 includes a hydraulic cylinder 31a that supports the punch 32 so as to be movable up and down, and a hydraulic unit 31c that sends hydraulic oil to the hydraulic cylinder 31a via a hydraulic pipe 31b.
The hydraulic pipe 31b is also connected to a separately operated punch up / down hydraulic cylinder 45, a separately operated die up / down cylinder 49, a punch widening hydraulic cylinder 53, and a die widening hydraulic cylinder 55. These hydraulic cylinders are connected to a hydraulic unit. The hydraulic oil can be fed from 31c. The number of hydraulic units is not limited to one, and a plurality of units may be prepared and individually connected to each hydraulic cylinder.

In addition, although the example which provided the separate die 39 was demonstrated above, the separate die 39 is not essential and does not need to be provided. FIG. 6 shows a press molding apparatus 57 including a die 59 that is not provided with a separate die as another aspect of the press molding apparatus 30.
The die 59 includes a pair of members configured to be widened, and has a recessed groove portion 59a at a portion corresponding to the separate punch 35.
Since the other configuration of the press molding apparatus 57 is the same as that of the press molding apparatus 30, the same components as those shown in FIG. 5 are denoted by the same reference numerals in FIG.

[Embodiment 3]
The widening means of the present invention is not limited to that shown in the second embodiment, and various modes can be adopted.
FIG. 7 shows a press forming apparatus 61 having a mold widening means 63 in which the means for widening the die 59 is changed as a modification of the press forming apparatus 57.
The means for widening the die 59 in the mold widening means 63 is provided by installing a plurality of die widening hydraulic cylinders 67 between a pair of members constituting the die 59 and a fixing portion 65 provided outside each member. By driving these members, the respective members are pulled toward the fixed portion 65 to be widened.
In FIG. 7, the other configuration of the press molding apparatus 61 is the same as that of the press molding apparatus 57 shown in FIG. 6, and thus the same components are denoted by the same reference numerals. Part of the hydraulic cylinder 31a and the hydraulic piping 31b are not shown.

  The number of punch widening hydraulic cylinders 53, die widening hydraulic cylinders 55, and die widening hydraulic cylinders 67 is not limited to those shown in FIGS. Just decide.

[Embodiment 4]
The die widening means may not use the punch widening hydraulic cylinder 53, the die widening hydraulic cylinder 55, the die widening hydraulic cylinder 67, or the like. As an example of such a configuration, FIG. 8 shows a press molding apparatus 69 having a mold widening means 71.
The punch 73 and the die 75 of the press molding apparatus 69 are configured by a pair of members that can be widened, like the press molding apparatus 30 (see FIG. 5).
The punch 73 and the die 75 are provided with a wedge receiving portion 73a and a wedge receiving portion 75a so as to have a substantially V-shaped cross section above the punch 73 and below the die 75 in a state where each pair of members is integrated. It has been.
The punch 73 is provided with a separately moving die 35 as in the press molding apparatus 30, and the die 75 is provided with a recessed groove 75 b at a portion corresponding to the separately moving die 35.
The vertical movement of the punch 73 is performed by a hydraulic cylinder 31 a (not shown) as in the press molding apparatus 30.

The mold widening means 71 includes a wedge receiving portion 73a, a wedge receiving portion 75a, a punch widening wedge 77 having a substantially trapezoidal cross section at the tip inserted into the opening side of the wedge receiving portion 73a, and the opening side of the wedge receiving portion 75a. A die widening wedge 79 having a substantially trapezoidal cross section at the tip inserted into the die is provided.
Each of the punch widening wedge 77 and the die widening wedge 79 can be driven by a wedge driving hydraulic cylinder 31d.
The die widening means 71 widens the punch 73 and the die 75 by inserting and sliding a punch widening wedge 77 and a die widening wedge 79 having a substantially trapezoidal cross section from the opening side of each V-shape. It is.

The V-shaped angle of the wedge receiving portion 73a, the angle of the tip of the punch widening wedge 77, the angle of the V-shape of the wedge receiving portion 75a, and the angle of the leading end of the die widening wedge 79 are the same.
The speed at which the punch widening wedge 77 and the die widening wedge 79 are inserted and slid is also the same.
Note that the V-shaped angle of the wedge receiving portion 73a and the tip wide angle of the punch widening wedge 77 are made the same, and the V-shaped angle of the wedge receiving portion 75a and the tip widening angle of the die widening wedge 79 are made the same. In this case, the drive amount of each wedge driving hydraulic cylinder 31d may be controlled so that the pushing amount of the punch widening wedge 77 and the die widening wedge 79 is the same.
By doing so, the movement distance and the movement timing of the punch 73 and the die 75 can always be the same.

  In the groove shape forming step and the elongation applying step, as an integration means for maintaining the integrated state of each pair of members of the punch 73 and the die 75, for example, a hydraulic mechanism or a spring that constantly applies a pressing force A member may be provided.

[Embodiment 5]
As shown in FIG. 9, the press molding apparatus 81 according to the present embodiment has the same basic configuration as the press molding apparatus 30 of the second embodiment, and in order to reduce friction with the plate material 11, A die peripheral roller 83 is provided on the periphery of the punch, and a punch shoulder roller 85 is provided on the punch shoulder.
In addition, in FIG. 9, the same code | symbol is attached | subjected to the same thing as the press molding apparatus 1. FIG. In FIG. 9, the hydraulic cylinder 31a, a part of the hydraulic piping 31b, and the hydraulic unit 31c are not shown.

The die peripheral roller 83 is a roller having the same radius of curvature as the peripheral edge R in the die recess, and is rotatably installed on the periphery in the die recess.
Friction can be reduced by rotating the die peripheral roller 83 when the plate material 11 is pressed into the die recess during pressing.

The punch shoulder roller 85 is a roller having the same radius of curvature as R of the punch shoulder portions, and is rotatably installed on the punch shoulder portions.
When the plate material 11 is pressed by the punch 32 during pressing, the punch shoulder roller 85 rotates to reduce friction, and the tension acting on the component vertical wall portion 17 is reduced, thereby reducing the plate thickness. Can be suppressed.
Further, when widening the double-sided punch 33 and the double-sided die 37, the tension acting in the widening direction can be made substantially uniform over the longitudinal direction of the hat cross-sectional component 13 (the direction perpendicular to the paper surface of FIG. 9), enabling stable molding. become.

In the above description, the example in which both the die peripheral roller 83 and the punch shoulder roller 85 are provided has been described, but only one of them may be provided.
The press molding method using the press molding apparatus 30, the press molding apparatus 57, the press molding apparatus 61, the press molding apparatus 69, and the press molding apparatus 81 shown in the second to fifth embodiments is the same as that in the first embodiment. What is necessary is just to carry out similarly to the press-molding method demonstrated by 1.

[Embodiment 6]
In the first to fifth embodiments described above, the method of press-molding the hat cross-section component 13 has been shown. However, the present invention is also applicable to the molding of a substantially W cross-section component in which two hat cross-section components 13 are connected in the width direction. The invention is applicable.
As shown in FIG. 10, the press molding apparatus 87 according to the present embodiment has a mold (W-shaped punch 89 and W-shaped mold) in which two molds of the press molding apparatus 30 (see FIG. 5) are connected in the width direction. It has a character die 91). In FIG. 10, the same components as those in the press molding apparatus 30 are denoted by the same reference numerals, and the hydraulic cylinder 31a, a part of the hydraulic piping 31b, and the hydraulic unit 31c are not shown.
The W-shaped punch 89 is composed of three members, and each of the two protrusions can be divided vertically from the center.
Similarly, the W-shaped die 91 is composed of three members, and each of the two recessed portions can be divided vertically from the center.
And the member arrange | positioned at both ends among the three members which comprise the W-shaped punch 89 and the W-shaped die | dye 91 can move to the widening direction.

In order to form a substantially W cross-section component using the press molding apparatus 87, the heated plate material 11 is placed so as to extend over both concave portions of the W-shaped die 91, and thereafter the same as in the first embodiment. Press forming.
If the press molding device 87 is used, it is possible to suppress a decrease in the plate thickness of the component vertical wall portion of the substantially W-cross-section component, and to reduce the plate thickness of the component bottom compared to the plate thickness of the component vertical wall portion. Weight reduction can be realized.
As with the press molding apparatus 81, the press molding apparatus 87 may be provided with a punch shoulder roller 85 and a die peripheral roller 83.

  In addition, in the said Embodiment 1- Embodiment 6, although the cross section of the front-end | tip of a separate punch was mentioned as an example, the shape of the front-end | tip of a separate punch is mentioned in the extension provision process. Any shape can be used as long as the portion corresponding to the bottom of the component can be elongated to reduce the plate thickness.

In the above description, the punch moves up and down as an example, but the die may move up and down.
In the above description, the driving direction of the punch and the die is the vertical direction. However, since the punch and the die only need to be driven relatively, the direction is not particularly limited.

In the above description, an example is shown in which the separately-moving punch is provided on the punch side, but the separately-moving punch may be provided on the die side. When the separate punch is provided on the die side, a recessed groove or a separate die into which the separate punch can be inserted is provided on the punch side.
Examples of such are shown in FIGS.
The press molding apparatus of FIG. 11 is a modification of the press molding apparatus 57 shown in FIG. In FIG. 11, the same components as those in FIG.

  A press molding apparatus 101 shown in FIG. 11 includes a punch 103, a die 105 having a recessed portion corresponding to the punch 103, and a driving device 31 (only a hydraulic pipe 31b is shown) that drives the punch 103 and the die 105. . The die 105 includes a pair of both-side dies 107 configured to be widened, and a separate punch 109 that is provided between the both-side dies 107 and moves separately from the both-side dies 107 with respect to the punch 103. . The punch 103 includes a pair of members configured to be widened, and has a recessed groove portion 103 a at a portion corresponding to the separate punch 109. Further, a die widening means 111 for widening the both-side punch 107 and the die 105 in a state where the punch 103 and the die 105 are at the bottom dead center is provided.

A press molding apparatus 121 shown in FIG. 12 is obtained by partially deforming the press molding apparatus 101 shown in FIG. 11 and providing a separate die 125 on the punch 122 side. This deformed portion will be described in detail with reference to FIG. In FIG. 12, the same components as those in FIG. 11 are denoted by the same reference numerals.
The punch 122 includes a pair of both side punches 123 configured to be widened, and a separate die 125 that is provided between the both side punches 123 and moves separately from the both side punches 123 with respect to the die 105. A concave groove 127 is formed by disposing the die 125 at a position recessed from both side punches 123.

Since the experiment which confirms the effect of the press molding method of this invention was conducted, the result is demonstrated below.
In the experiment, press molding is performed by the press molding method shown in FIG. 2, and the thickness, bending crushing performance, and weight of the vertical wall portion and punch bottom portion of the molded product are evaluated.

In this example, as Invention Example 1, a straight part having a hat cross section (hereinafter, simply referred to as “hat cross section part 93”) was formed using a press molding apparatus 30 (see FIG. 5).
The plate material to be formed was a hot press steel plate having a thickness of 1.8 mm and heated to a high temperature (950 ° C.).
In press molding, before the center of the part corresponding to the bottom of the part is extended downward at the bottom dead center, the both-side punch 33 is slightly widened so that the part corresponding to the vertical part of the part is secured with the both-side dies 37. I was pinched.

  Further, as Invention Example 2, an elongation imparting step was performed by heating in advance using a separate punch 35 with a heater 43, and press molding was performed in the same manner as in Invention Example 1 under other conditions.

  As a comparative example, a hat cross-section component 93 was formed by conventional press molding using a normal punch and die.

The bending crush performance was obtained by performing a bending crush test. In the bending crushing test, as shown in FIG. 13, both ends 1/6 are supported with the opening side of the hat cross-section part 93 facing down, and a downward load (see the thick arrow in FIG. 13) is applied to the center at a constant speed. The load when plastic bending occurred was measured.
Table 1 shows the experimental results.

  Table 1 shows the material plate thickness (mm), component vertical wall thickness (mm), component bottom thickness (mm), bending crushing performance comparison, and weight comparison for each invention example and comparative example. Yes. In Table 1, the bending crush performance and weight are based on Example 1 of the present invention as 100 (reference).

In the present invention example 1 and the present invention example 2, the sheet thickness is secured in a state in which the portion corresponding to the component vertical wall portion is clamped by the both-side punch 33 and the both-side die 37, and the portion corresponding to the component bottom portion is overhanged. As a result, the thickness of the vertical wall portion of the component, which is important for the collision performance, is hardly reduced, which is preferable.
On the other hand, in the comparative example, the plate | board thickness of the component vertical wall part was comparatively thin, and the bending crush performance was inferior to the example of this invention.

Further, in the present invention example 1 and the present invention example 2, the thickness of the bottom part of the component that does not contribute much to the bending crush performance is thinner than that of the comparative example, and the hat cross section has the same dimensions (width, height, length, flange length). The weight of the part 93 was reduced by about 30%.
As described above, it was confirmed that the present invention is effective for reducing the weight while maintaining the bending crush performance.
In Invention Example 1 and Invention Example 2, Invention Example 2 in which the separately operated punch was heated was able to reduce the plate thickness at the bottom of the component, thereby further reducing the weight.

1 Press forming apparatus (Embodiment 1)
DESCRIPTION OF SYMBOLS 2 Punch 3 Both-sides punch 5 Separately driven punch 6 Die 7 Both-sided die 9 Separately-moved die 11 Molded board material 11a Overhang | projection part 12 Recessed groove part 13 Hat cross-section part 15 Part bottom part 15a Thin part 17 Parts vertical wall part 21 Cooling oil supply apparatus 23 Cooling oil piping 30 Press molding device (Embodiment 2)
31 Driving Device 31a Hydraulic Cylinder 31b Hydraulic Piping 31c Hydraulic Unit 31d Wedge Driving Hydraulic Cylinder 32 Punch 33 Both Sides Punch 33a Separately Moved Punch Installation Part 35 Separately Moved Punch 36 Die 37 Both Sides Die 37a Separately Moved Die Installation Part 39 Separately Die 40 Depressed Groove 41 Die widening means 43 Heater 45 Separately operated punch vertical movement hydraulic cylinder 49 Separately movable die vertical movement cylinder 53 Punch widening hydraulic cylinder 55 Die widening hydraulic cylinder 57 Press molding device (without separate die)
59 Die 59a Recessed groove portion 61 Press forming apparatus (Embodiment 3)
63 Die widening means 65 Fixed portion 67 Die widening hydraulic cylinder 69 Press molding apparatus (Embodiment 4)
71 Die widening means 73 Punch 73a Wedge receiving portion 75 Die 75a Wedge receiving portion 75b Recessed groove portion 77 Punch widening wedge 79 Die widening wedge 81 Press forming apparatus (Embodiment 5)
83 Die peripheral roller 85 Punch shoulder roller 87 Press molding device (Embodiment 6)
89 W-shaped punch 91 W-shaped die 93 Hat cross-section component 101 Press molding device (other modes)
DESCRIPTION OF SYMBOLS 103 Punch 103a Recessed groove part 105 Die 107 Both-sides die 109 Separately moving punch 111 Mold widening means 121 Press molding apparatus (other aspect)
122 Punch 123 Both-sided punch 125 Separate die 127 Recessed groove

Claims (13)

A press molding method for press-molding a heated plate material using a punch and a die configured to be widened on a molded part having a groove portion having vertical walls on both sides,
A groove shape forming step of forming a groove shape so that the punch and the die do not contact with a portion corresponding to the bottom of the groove shape portion of the plate material to be formed; and a groove bottom portion formed by the groove shape forming step An elongation imparting step for imparting elongation to reduce the thickness of the bottom of the groove, and a widening step for moving the punch and the die in the widening direction to extend the groove bottom to which the elongation is imparted in the width direction. A press molding method characterized by the above.   The elongation imparting step imparts elongation by causing the groove bottom portion formed in the groove shape forming step to project by a separate punch provided between the punches so as to be relatively movable separately from the punch. The press molding method according to claim 1.   The elongation imparting step imparts elongation by causing the groove bottom portion formed in the groove shape forming step to project by a separate punch provided between the dies so as to be relatively movable separately from the die. The press molding method according to claim 1.   The press molding method according to any one of claims 1 to 3, further comprising a cooling step of cooling the bottom of the groove in a state where the plate material to be molded is sandwiched between molds after the widening step. . A press molding apparatus that press-molds a molded part having a groove portion having vertical walls on both sides using a heated plate material,
A punch having a convex part, a die having a concave part corresponding to the convex part of the punch, and a driving device for driving at least one of the punch or the die,
The punch comprises a pair of both side punches configured to be widened, and a separate punch provided between the both side punches and moving separately from the both side punches with respect to the die,
The die includes a pair of members configured to be widened, and has a recessed groove portion in a portion corresponding to the separate punch,
A press forming apparatus comprising a mold widening means for widening the both-side punch and the die in a state where the punch and the die are at bottom dead center. The die comprises a pair of both-side dies that are configured to be widened, and a separate die that is provided between the both-side dies and moves separately from the both-side dies with respect to the punch,
6. The press forming apparatus according to claim 5, wherein the separately moved die is disposed at a position recessed from the both-side dies so that the recessed groove portion is formed. A press molding apparatus that press-molds a molded part having a groove portion having vertical walls on both sides using a heated plate material,
A punch having a convex part, a die having a concave part corresponding to the convex part of the punch, and a driving device for driving at least one of the punch or the die,
The die comprises a pair of both-side dies that are configured to be widened, and a separate punch that is provided between the both-side dies and moves separately from the both-side dies with respect to the punch,
The punch includes a pair of members configured to be widened, and has a recessed groove portion in a portion corresponding to the separately-moving punch,
A press forming apparatus comprising a mold widening means for widening the both-side punch and the die in a state where the punch and the die are at bottom dead center. The punch includes a pair of both side punches configured to be widened, and a separate die provided between the both side punches and moving separately from the both side punches with respect to the die.
8. The press forming apparatus according to claim 7, wherein the recessed die is formed by disposing the separate die at a position recessed from the both side punches.   The press molding apparatus according to any one of claims 5 to 8, wherein the die is provided with a roller that reduces friction with the molding target plate at a peripheral edge of the recessed portion.   The press forming apparatus according to any one of claims 5 to 9, wherein the punch is provided with a roller on a shoulder portion of a convex portion to reduce friction with the plate material to be formed.   The press molding apparatus according to any one of claims 5 to 10, further comprising a coolant supply means for supplying a coolant for cooling the bottom of the plate material to be formed to a bottom dead center. .   The press molding apparatus according to any one of claims 5 to 11, wherein a tip surface of the separate punch is formed in an arc shape.   The press molding apparatus according to any one of claims 5 to 12, further comprising heating means for heating the separate punch.

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