Patent Grant
10022766
This application relates to a technique of press forming for forming a material into a press-formed part having a curved vertical wall portion, such as a curved channel part. This technique is particularly preferable for press forming on a portion of a curved portion of a vertical wall portion that is deformed in a manner of stretch flange deformation by forming.
In recent years, to attain both crush safety of a vehicle and weight reduction of a vehicle body, a steel sheet with a higher strength is demanded. However, as the tensile strength of a steel sheet increases, the ductility significantly relating to press formability tends to decrease. Owing to this, a shape that can be formed even with a steel sheet having a low ductility is being studied for example, by simplifying the shape of a press-formed part. A press forming method suitable for a steel sheet having a high strength is being studied.
In case of press forming a steel sheet having a low ductility and a high strength, deep drawing or stamping (bending) is typically employed. For example, a channel part with a simple shape including a vertical wall portion and a top portion continuous to the vertical wall portion but not including a curved portion in the vertical wall portion is manufactured by stamping. Also, a flanged channel part is manufactured by deep drawing.
In stamping, a blank (a flat-sheet-shaped processing material) is arranged on a punch, and the blank is bent with a die, to obtain a product shape. To restrict generation of a wrinkle at a blank portion, which contacts an upper section of the punch, a blank may be pinched and held by the punch and a pad.
In deep drawing, first, a blank holder is arranged at a position corresponding to a flange portion, a blank is arranged on a punch and the blank holder, and a die is arranged above the blank. Then, by lowering the die, the blank is held by the die and the blank holder, and the blank is bent while a load of a proper tensile force is applied to the blank. At this time, the material (the blank) is largely drawn into an area between the punch and the die as the result that the material is held by the die and the blank holder forms a vertical wall portion. Hence, the vertical wall portion is easily formed even when the material has a low ductility.
As a method of adjusting a tensile force, there may be a method of changing a holding force (a cushion pressure) of holding the blank by the die and the blank holder, and a method of arranging a bead at the holding position. If the tensile force applied to the blank is too weak, the material excessively flows to the vertical wall portion, and a wrinkle (a material excess) is likely generated. In contrast, if the tensile force is excessive, the amount of the material flowing to the vertical wall portion is reduced. At forming the vertical wall portion the material is required to be stretched and a crack may be generated if the material has a low ductility.
A press-formed part for a vehicle includes a curved channel part having a curved portion in a vertical wall portion (for example, a lower arm part shown in
If a curved channel part having a curved portion in a vertical wall portion is manufactured by stamping, when a material is drawn into a vertical-wall-portion formation space of a die and the vertical wall portion is formed, the line length of the material is sufficient at the curved portion, and the material is stretched and deformed in a circumferential direction of the curved portion. This deformation is called “stretch flange deformation.” The stretch flange deformation becomes larger as the material is drawn into the vertical-wall-portion formation space from a position more separated from the curved portion (for example, a portion 42a in
Even when a curved channel part with a flange portion is manufactured by deep drawing, similarly, the flange portion is stretched in the circumferential direction of the above-described curved portion, and hence a crack caused by stretch flange deformation may be generated.
The crack caused by stretch flange deformation is a problem particularly for a material, such as a steel sheet with a high strength, the material which likely has an insufficient ductility. Also, even in a case of a material other than the steel sheet, if the material has a low ductility, a crack caused by stretch flange deformation may be generated. For example, there may be a case in which an aluminum alloy sheet is used for an outer panel of a vehicle for reducing the weight of a vehicle body of the vehicle. In this case, since aluminum alloy tends to have lower press formability than that of a steel sheet, if press forming with stretch flange deformation is executed, a crack may be generated in the outer panel.
To prevent a crack caused by this stretch flange deformation, Patent Literature 1 suggests a method of previously applying a material excess portion (for example, a protruding and depressed shape) at a position of a blank expected to have stretch flange deformation by press forming, and hence preventing the line length of a material from being insufficient in a curved portion during press forming. Also, Patent Literature 2 suggests a method of dispersing stretch flange deformation by an outer edge portion of a vertical wall portion, and hence preventing stretch flange deformation from being locally concentrated.
PTL 1: Japanese Unexamined Patent Application Publication No. 2002-1445
PTL 2: Japanese Unexamined Patent Application Publication No. 2009-160655
The methods suggested in Patent Literatures 1 and 2 are each a method of preventing the line length of the material from being insufficient even when stretch flange deformation occurs, but are not each a method of preventing occurrence of the stretch flange deformation which may cause a crack to be generated in the outer edge portion of the vertical wall portion or the flange portion. Owing to this, these methods have limitation, and cannot prevent a crack caused by stretch flange deformation from being generated, if large stretch flange deformation occurs depending on the height of the vertical wall portion or the curved shape, or if the material has low press formability.
An object of disclosed embodiments is to provide a press forming method of manufacturing a press-formed part, such as a curved channel part, having a curved portion in a vertical wall portion by press forming, the method restricting stretch flange deformation, which occurs in the vertical wall portion and a flange portion.
To address the above-described problems, according to embodiments, there is provided a press forming method of press-forming a flat-sheet-shaped processing material (a blank) into a press-formed part, the processing material including a base section and a deformation section continuous to the base section and including a portion to be a vertical wall portion, the press-formed part having the vertical wall portion formed when the processing material is bent in at least a boundary portion between the base section and the vertical wall portion, the vertical wall portion having a curved portion being curved in a depressed shape toward the base section. As a step of forming the vertical wall portion, the press forming method includes a shear deformation step of individually restraining a boundary-side portion of the base section with respect to the deformation section and an outer portion of the deformation section, shear-deforming the portion to be the vertical wall portion of the deformation section in a sheet face, and causing a material to flow from a portion separated from the curved portion toward the curved portion in an outer edge portion of the portion to be the vertical wall portion.
For example, as shown in
As shown in
With the method of this aspect, as shown in
Also, in the shear deformation step, since the outer portion 12b and the boundary-side portion 11a are restrained, stretch flange deformation and generation of a wrinkle in these portions are restricted.
Also, in the shear deformation step, since the outer portion 12b and the boundary-side portion 11a are restrained, the material cannot be moved, and the portion 12a to be the vertical wall portion is shear-deformed in the sheet face. Accordingly, the shear deformation step can be stably executed even if the surface roughness and clearance of a die; the cushion force; the intensity, stretch, and thickness of a blank; etc., vary during volume production.
In the press forming method according to this aspect, in the step of forming the vertical wall portion, when viewed in a thickness direction of the flat-sheet-shaped processing material, from a state in which a second restraining section that restrains the outer portion of the deformation section is separated from a first restraining section that restrains the boundary-side portion, the second restraining section may be relatively moved in a direction in which a separation distance between the first restraining section and the second restraining section decreases as the boundary portion is bent.
In the press forming method of this aspect, the shear deformation step can be executed by a method of the following configuration (3) or (4).
(3) A method is moving the restrained outer portion so that the portion to be the vertical wall portion is rotated around a bending point of the curved portion on a boundary line between the base section and the deformation section. In
(4) Another method is linearly moving the restrained outer portion in a direction in which an angle with respect to the sheet face of the blank is in a range from 30° to 60°. The angle is preferably in a range from 40° to 50°, and is more preferably 45°.
With the method of the configuration (3), in the shear deformation step, the cross-sectional shape and dimension of the portion to be the vertical wall are hardly changed in a portion other than a portion which is changed to the bent portion (boundary portions of the vertical wall portion with respect to the top portion and the flange portion). Accordingly, a stretch or a wrinkle is hardly generated in the vertical wall portion.
With the method of the configuration (4), in the shear deformation step, the cross-sectional shape and dimension of the portion 12a to be the vertical wall portion are changed. However, by setting the angle in the range from 30° to 60°, a stretch which occurs in the vertical wall portion is not so large that the stretch causes a crack to be generated. A wrinkle generated in the vertical wall portion can be brought into a removable state in post-processing.
If the angle is smaller than 30°, when the vertical wall portion is formed only in the shear deformation step, the corrected degree of deformation of the portion to be the vertical wall portion (the state in which the material is excessive and bent) is insufficient, and a wrinkle generated in the vertical wall portion may not be removed by post-processing. If the angle exceeds 60°, the material of the portion to be the vertical wall portion is largely stretched (the direction of this stretch differs from the direction of the shear deformation), and a crack may be generated due to insufficiency in ductility of the material.
The press forming method of this aspect may be executed in combination with the shear deformation step, a deep drawing step of related art, and a stamping step of related art like the configurations (5) to (7).
(5) As the step of forming the vertical wall portion, the shear deformation step is executed and then a deep drawing step is executed. (6) As the step of forming the vertical wall portion, a deep drawing step is executed and then the shear deformation step is executed. (7) The curved channel part does not have a flange portion at an outer side of the vertical wall portion, and as the step of forming the vertical wall portion, the shear deformation step is executed and then a stamping step is executed.
In each of the configurations (5) and (6), by executing the shear deformation step as pre-processing or post-processing of the deep drawing step being a press forming method of related art, as compared with a case in which the vertical wall portion is formed only in the deep drawing step, stretch flange deformation of the curved channel part is reduced.
In the press forming method of this aspect, the outer portion 12b of the deformation section is present in a flange shape at the outside of the vertical wall portion. Accordingly, if a curved channel part without a flange portion is manufactured by the press forming method of this aspect, at the outside of the vertical wall portion, post-processing is required. The post-processing may be a method of removing the flange-shaped outer portion 12b by using laser cutting and a trim die.
As the post-processing, with the configuration (7), instead of removing the outer portion 12b, the stamping step being a press forming method of related art is executed. With the configuration (7), as compared with a case in which the vertical wall portion is formed only in the stamping step, stretch flange deformation of the curved channel part is reduced. Also, even in a method executing post-processing of removing the flange-shaped outer portion 12b after the shear deformation step is executed, as compared with the case in which the vertical wall portion is formed only in the stamping step, stretch flange deformation of the curved channel part is reduced.
The press forming method of this aspect may include the following configuration (8) or (9). (8) The press forming method includes a wrinkle stretching step of stretching a wrinkle, which is generated in the vertical wall portion, by pinching the vertical wall portion with a die after the shear deformation step.
At this time, if a press surface of the die, which contacts the vertical wall portion, has a depression and a protrusion to increase a line length of the vertical wall portion, a wrinkle in the vertical wall portion is further stretched.
(9) The shear deformation step is executed on a blank that is heated at a temperature in a range from 300° C. to 1000° C. The temperature is more preferably in a range from 400° C. to 900° C.
With the configuration (9), the material of the blank is softened in the shear deformation step. Accordingly, shear deformation likely occurs in the portion to be the vertical wall portion, and even if a wrinkle is generated in the portion to be the vertical wall portion, the wrinkle is likely stretched. The heating position of the blank may be the portion to be the vertical wall portion, or the blank may be entirely heated. Even if the blank is entirely heated, the material of the portion to be restrained is cooled by the die and is hardened. Accordingly, the entirely heated blank does not affect the restraint.
If the heating temperature is lower than 300° C., the material is insufficiently softened. Hence, there is no particular advantage of heating. If the heating temperature is higher than 1000° C., a thick scale is generated on the surface of the blank (the steel sheet). The method of heating the blank may be a typical heating method, such as heating in a heating furnace, high-frequency heating, or electrical heating.
It is to be noted that the material of the blank to be used in the press forming method of this aspect may be any of materials of blanks used in press forming methods of related art. For example, even in a case of a blank with difficulty in press forming by the methods of related art, such as a steel sheet with a high strength of 590 MPa or higher or an aluminum alloy sheet, by executing the press forming method of this aspect, the curved channel part in which stretch flange deformation and generation of a wrinkle are restricted can be obtained.
<Blank Restraining Method>
In the press forming method of this aspect, the base section and the outer portion of the deformation section of the blank are individually restrained in the shear deformation step. The restraining method may employ a known method of related art. For example, there may be a method of fixing a blank by pinching the blank with a jig, a method of providing a protrusion on a die and hooking a blank to the protrusion, and a method of fixing a blank with a magnetic force. One of these methods may be employed or these methods may be combined and employed.
As a specific example, there may be a method of providing a screw such as a bolt in the jig that pinches the blank. With this method, a force for fastening the blank with the jig may be applied by a fastening force of the screw. Alternatively, a bead portion may be provided in the jig that pinches the blank. With this method, bending/unbending deformation and frictional resistance which are received by the material when the material moves through the bead portion may be used as a restraining force against the movement of the material. There may be also a method of making a protruding and depressed shape by knurling in the jig that pinches and fixes the blank. With this method, since the protruding and depressed shape bites into the blank, the movement of the material can be likely disturbed. The method of knurling processing may be a method of cutting, and transferring the protruding and depressed shape by strongly pressing the shape to the jig. However, any method may be employed as long as the protruding and depressed shape is provided in the jig.
If the portion of the jig with the protruding and depressed shape is hardened, wearing and chipping of the protruding and depressed shape can be prevented. The hardening method may be a method of applying hardening processing, such as high-frequency hardening, carburizing, flame hardening, or laser hardening; or a surface modifying method, such as low-temperature sulfurizing processing, a chemical vapor deposition method, or a physical vapor deposition method.
<Moving Method of Restrained Blank>
When the shear deformation step is executed with the configuration (3) or (4), the moving method while the outer portion of the blank is restrained may be a method of using a motion of slide of a press machine which is used by a typical press forming method, by converting the motion in the up-down direction into a motion made with the configuration (3) or (4). In this case, a mechanism using an inclined surface represented by a cam mechanism, a link mechanism, or a mechanism using a lever may be employed. In addition to the use of a driving force of the press machine, a method using a cylinder utilizing electricity, an air pressure, or a hydraulic pressure may be employed.
With the press forming method of disclosed embodiments, when press forming is executed to obtain the press-formed part having the curved portion in the vertical wall portion, stretch flange deformation, which occurs in at least the vertical wall portion among the vertical wall portion and the flange portion can be restricted.
Accordingly, a crack due to the stretch flange deformation in the press-formed part having the curved portion in the vertical wall portion can be prevented from being generated. Also, the shear deformation step can be stably executed even if various variations are made during volume production. Accordingly, the shear deformation step can make significant contribution to decrease in defective rating of pressed products.
Further, by applying disclosed embodiments to a material with difficulty in press forming, such as a steel sheet with a high strength of 590 MPa or higher or an aluminum alloy sheet, press-formed parts with various shapes can be manufactured. Accordingly, the disclosed embodiments can make significant contribution to decrease in weight and increase in strength of parts.
Disclosed embodiments are described below; however, this disclosure is not limited to these embodiments. In the embodiments described below, a curved channel part is described as an example of a press-formed part being a subject to be manufactured. However, disclosed embodiments are not limited to the curved channel part. Any part may be a subject of embodiments as long as the part is a press-formed part having a vertical wall portion having a curved portion that is curved in a depressed shape toward a top portion during forming.
[First Embodiment]
In this embodiment, the curved channel part shown in
As shown in
The vertical wall portion 22 with the curved portion 22a and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 are formed by the following method. In this case, a portion other than the curved portion 22a may be formed in a typical deep drawing step. It is to be noted that the vertical wall portion 23 without a curved portion and the flange portion 25 continuous to the vertical wall portion 23 are formed in the typical deep drawing step.
As shown in
The blank 1 is a uniform single sheet. As shown in
First, as shown in
In this case, the punch 31 and the first pad 32 configure a first restraining section, and the blank holder 33 and the second pad 34 configure a second restraining section.
Then, as shown in
In the sharing deformation step, as shown in
Also, with the method of this embodiment, in the shear deformation step, the cross-sectional shape or the dimension of the portion 12a to be the vertical wall portion of the blank 1 is not changed in a portion other than the bent portion. Accordingly, a wrinkle is hardly generated in the vertical wall portion 22 of the curved channel part 2.
Further, since the outer portion 12b is moved while being restrained and hence becomes the flange portion 24, stretch flange deformation hardly occurs in the outer edge portion of the curved portion 24a of the flange portion 24, and a wrinkle is hardly generated in the flange portion 24.
[Second Embodiment]
Also in this embodiment, similarly to the first embodiment, the curved channel part 2 having the shape shown in
The method in this embodiment differs from the method in the first embodiment in the moving method of the blank holder 33 and the second pad 34 that restrain the outer portion 12b, and is similar to the method in the first embodiment for the other points.
First, as indicated by a solid line in
Then, the blank holder 33 and the second pad 34 that restrain the outer portion 12b are linearly moved obliquely downward to approach the punch 31 and the first pad 32 when viewed in the thickness direction of the blank as indicated by arrow C in
With this sharing deformation step, as indicated by a two-dot chain line in
In the sharing deformation step, as shown in
Hence, in the curved channel part 2 manufactured in this embodiment, stretch flange deformation hardly occurs in the outer edge portion of the curved portion 22a of the vertical wall portion 22.
With the method in this embodiment, in the shear deformation step, the cross-sectional shape of the portion 12a to be the vertical wall portion of the blank 1 is changed. If the outer portion 12b is moved by θ=45°, even when press forming is executed at a room temperature, a wrinkle that may cause a problem in quality is hardly present in the vertical wall portion 22 of the curved channel part 2.
If the moving angle (θ) of the outer portion 12b with respect to the sheet face of the blank 1 is not 45°, as compared with the case of θ=45°, a possibility of that a wrinkle and a crack are generated in the vertical wall portion 22 increases. If θ is in the range from 30° to 60°, a crack caused by a stretch generated in the vertical wall portion 22 can be avoided, and a wrinkle generated in the vertical wall portion 22 can be removed by post-processing etc.
Further, since the outer portion 12b is moved while being restrained and hence becomes the flange portion 24, stretch flange deformation hardly occurs in the outer edge portion of the curved portion 24a of the flange portion 24, and a wrinkle is hardly generated in the flange portion 24.
Also, if the portion 12a to be the vertical wall portion is further moved from the state in
[Third Embodiment]
Also in this embodiment, similarly to the first embodiment, the curved channel part 2 having the shape shown in
As shown in
Similarly to the method of the second embodiment, the blank holder 33 and the second pad 36 that restrain the outer portion 12b are linearly moved obliquely downward in which the angle (θ) with respect to the sheet face of the blank 1 is in the range from 30° to 60° as indicated by arrow C. By the linear movement, shear deformation occurs in the sheet face of the portion 12a to be the vertical wall portion of the blank 1, and as indicated by a two-dot chain line in
Then, by moving the blank holder 33 and the second pad 36, finally, a portion 12f of the portion 12a to be the vertical wall portion is pinched by the protruding portion 35a of the punch 35 and the depressed portion 36a of the second pad 36, and becomes a surface substantially perpendicular to a surface of the flange portion 24. This step is a wrinkle stretching step.
At this time, if a wrinkle is generated in the vertical wall portion when the vertical wall portion is pinched by the die, the wrinkle is likely stretched. In particular, the line length of the portion 12a to be the vertical wall portion is elongated by the amount corresponding to the depressed portion 36a, that is, the line length can be increased. As the result, even if a wrinkle is generated in the vertical wall portion, the wrinkle can be stretched.
The wrinkle stretching step may be executed at last after the shear deformation step described in the first embodiment etc. Since the wrinkle stretching step is executed continuously to the shear deformation step, the number of steps can be prevented from being increased for the wrinkle stretching step.
[Fourth Embodiment]
Also in this embodiment, similarly to the first embodiment, the curved channel part 2 having the shape shown in
In this embodiment, the vertical wall portion 22 is formed by two steps including the shear deformation step and then a deep drawing step. Hence, the outer portion 12b that is restrained in the shear deformation step includes a portion of the portion to be the vertical wall portion 22. Also, an inner portion (a portion near the base section 11) 12c being a portion to be the vertical wall portion 22 is shear-deformed in the sheet face.
A die used in the shear deformation step is basically the same as that of the second embodiment. As shown in
First, the boundary-side portion 11a of the base section 11 of the blank 1 is pinched and restrained by the punch 31 and the first pad 32, and the outer portion (the portion of the portion to be the vertical wall portion 22 and the portion to be the flange portion 24) 12b of the deformation section 12 is pinched and restrained by the blank holder 33 and the second pad 34.
Then, similarly to the method of the second embodiment, the blank holder 33 and the second pad 34 that restrain the outer portion 12b are linearly moved in a direction in which the angle (θ) with respect to the sheet face of the blank 1 is in the range from 30° to 60° as indicated by arrow C in
This shear deformation step is executed until a timing before the angle between the boundary-side portion 11a of the base section 11 and the inner portion 12c of the deformation section 12 reaches an angle of a final product.
Then, as shown in
[Fifth Embodiment]
Also in this embodiment, similarly to the first embodiment, the curved channel part 2 having the shape shown in
In this embodiment, the vertical wall portion 22 is formed by two steps including the deep drawing step and then the shear deformation step.
First, as shown in
Accordingly, the outer portion 12d is bent while being drawn and stretched toward the punch 31, and the blank 1 obtains a shape having a bent portion between the portion 12a to be the vertical wall portion and the outer portion 12b. The deep drawing step is executed until an angle β between the portion 12a to be the vertical wall portion and a side surface of the die 37 becomes, for example, in a range from 45° to 60°.
Then, as shown in
[Sixth Embodiment]
In this embodiment, a curved channel part shown in
As shown in
As shown in
Then, the blank holder 33 and the second pad 34 restraining the outer portion 12b are moved so that the portion 12a to be the vertical wall portion is rotated around the boundary point B with respect to the boundary-side portion 11a as indicated by arrow A. This corresponds to the shear deformation step. This movement is stopped at a position at which the portion 12a to be the vertical wall portion is bent by a predetermined angle (α, α being preferably in a range from 20° to 70°, in
Then, as shown in
It is to be noted that the shear deformation step that is executed before the stamping step may be executed by linearly moving the restrained outer portion 12b in the direction in which the angle (θ) with respect to the sheet face of the blank 1 is in the range from 30° to 60° as indicated by arrow C in
Also, the curved channel part shown in
[Other Embodiment]
As shown in
Even in this curved channel part 60, stretch flange deformation likely occurs. By employing press forming according to embodiments (for example, press forming described in the first to sixth embodiments), a crack due to stretch flange can be restricted.
Since the top portion 61 is also curved, facing surfaces of the punch 31 and the first pad 32 for holding the blank have surface shapes along the curved top portion.
Also, even if the curve of the vertical wall portion is a curved portion deformed in both directions of an off-plane direction and a vertical direction, the curved portion may be a subject of disclosed embodiments.
By the method described in any of the first to sixth embodiments and a press forming method of related art (deep drawing), the vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In deep drawing, a material located at the flange portion is drawn into the vertical wall portion, and hence the shape of the flange portion after forming is different from the method of any of the first to fifth embodiments. The shapes of the blanks were changed between the methods according to the first to fifth embodiments and the deep drawing, so that the flange width near the curved portion of the vertical wall portion was 50 mm after press forming. The shape of the blank for deep drawing was obtained by inverse analysis based on the total strain theory.
Also, for the blank, blanks of five types of materials shown in Table 1 each having a thickness of 1.2 mm were prepared.
It is to be noted that a blank was heated by using a heating furnace, and the temperature of the blank before forming was measured by using an infrared radiation thermometer.
<Sample No. 1-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
Portions of inner peripheral surfaces of the punch 31 and the first pad 32, the portions which correspond to the curved portion 22a, each have a curvature radius R1 of 100 mm. Portions of outer peripheral surfaces of the blank holder 33 and the second pad 34, the portions which correspond to the curved portion 22a, each have a curvature radius R2 of 90 mm. The arrangement distance S0 between the punch 31 and the second pad 34 shown in
As shown in
Then, by moving the blank holder 33 and the second pad 34 along arrow C in
A, is a plan view of the die and blank in this state.
In this example, the shear deformation step was executed at a room temperature by using a non-heated blank.
For the obtained curved channel part, a generated crack was evaluated as shown in Table 2, and a generated wrinkle was evaluated as shown in Table 3.
As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 1-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 1-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 1-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C. Also, from the state in
For each obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 2-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
A die the same as that of the sample No. 1-1 was used except that a moving mechanism of the blank holder 33 and the second pad 34 was different. The arrangement distance S0 between the punch 31 and the second pad 34 shown in
First, the boundary-side portion 11a of the base section 11 of the blank 1 was pinched and restrained by the punch 31 and the first pad 32, and the outer portion (the portion to be the flange portion) 12b of the deformation section 12 was pinched and restrained by the blank holder 33 and the second pad 34.
Then, as shown in
In this example, the shear deformation step was executed at a room temperature by using a non-heated blank.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 2-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 2-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 2-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C. Also, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 3-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. In the case of the sample No. 3-1, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 3-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 3-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 3-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 4-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. In the case of the sample No. 4-1, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 4-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 4-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 4-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 5-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was x (noticeable wrinkle).
<Sample No. 5-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was x (noticeable wrinkle).
<Sample No. 5-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was x (noticeable wrinkle).
<Sample No. 5-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was x (noticeable wrinkle).
<Sample No. 6-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was x (crack in vertical wall portion), and the wrinkle was x (noticeable wrinkle).
<Sample No. 6-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was x (crack in vertical wall portion), and the wrinkle was x (noticeable wrinkle).
<Sample No. 6-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was x (crack in vertical wall portion), and the wrinkle was x (noticeable wrinkle).
<Sample No. 6-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
As shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was x (crack in vertical wall portion), and the wrinkle was x (noticeable wrinkle).
<Sample No. 7-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
The die used in the deep drawing step is provided by replacing the second pad 34 with the die 37 in the die shown in
First, as shown in
Then, the die 37 was replaced with the second pad 34, the blank holder 33 and the second pad 34 were connected to the same moving mechanism as that used for the sample No. 2-1, and as shown in
Then, the angle θ with respective to the sheet face of the portion 12a to be the vertical wall portion of the blank 1 was set at 60°, and the blank holder 33 and the second pad 34 were linearly moved along arrow C. The movement was executed until a distance S between the punch 31 and the second pad 34 became 10 mm. Accordingly, the portion 12a to be the vertical wall portion was shear-deformed and the vertical wall portion 22 was formed. A height T2 of the vertical wall portion 22 in
In this example, the shear deformation step was executed at a room temperature by using a non-heated blank.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 7-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 7-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 7-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C. Also, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 8-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In the shear deformation step, the same die as that used for the sample No. 2-1 was used, and the arrangement distance S0 (see
As shown in
Then, as shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 8-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 8-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 8-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C. Also, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 9-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
The die used for press forming is the same as the die for deep drawing of related art, and includes a die 51, a punch 52, and a pair of blank holders 53. A portion of an inner peripheral surface 51a of a depressed portion of the die 51, which corresponds to the curved portion 22a, has a curvature radius R1 of 100 mm. A depth F of the depressed portion of the die 51 is 100 mm. A portion of an outer peripheral surface 52a of the punch 52, which corresponds to the curved portion 22a, has a curvature radius R2 of 90 mm.
A distance K between the inner peripheral surface 51a of the die 51 and the outer peripheral surface 52a of the punch 52 was set at 10 mm. A chamfering radius R3 of an upper-end corner portion of the punch 52 was set at 10 mm, and a chamfering radius R4 of a lower-end corner portion of the inner peripheral surface 51a of the die 51 was set at 10 mm.
As shown in
Accordingly, as shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, if the material of the used blank was “270,” the crack was Δ, and otherwise, the crack was x (F). If the material of the used blank was any of “270” and “aluminum alloy,” the wrinkle was O (very small wrinkle negligible in quality), and otherwise, the wrinkle was x (noticeable wrinkle).
That is, in this example, if a 270 MPa grade steel sheet was used as the blank, the wrinkle evaluation had no problem; however, necking occurred at an end portion of the vertical wall portion. If any of 590, 980, 1180 MPa grade steel sheets with high strengths was used as the blank, a noticeable wrinkle was generated in the vertical wall portion, and a crack was generated in the flange portion. If an aluminum alloy sheet was used as the blank, the wrinkle evaluation had no problem; however, a crack was generated in the flange portion.
<Sample No. 9-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
In this example, the deep drawing step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was x (crack in vertical wall portion). If the material of the used blank was any of “980” and “1180,” the wrinkle was x (noticeable wrinkle), and otherwise, the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 10-1>
The curved channel part 4 shown in
In the shear deformation step, the same die as that used for the sample No. 2-1 was used, and the arrangement distance S0 between the punch 31 and the second pad 34 was set at 50 mm.
As shown in
In this state, the portion 12a to be the vertical wall portion becomes an inclined wall portion, and the outer portion 12b becomes a flange portion. The shear deformation step was executed at a room temperature by using a non-heated blank until a height T1 of the inclined wall portion became 25 mm.
Then, as shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 10-2>
The curved channel part 4 shown in
In this example, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 10-3>
The curved channel part 4 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 10-4>
The curved channel part 4 shown in
In this example, the shear deformation step was executed by using a blank heated at 300° C. Also, from the state in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 11-1>
The curved channel part 4 shown in
A die obtained by removing the blank holders 53 from the die shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, if the material of the used blank was “270,” the crack was Δ, and otherwise, the crack was x (K). If the material of the used blank was any of “270” and “aluminum alloy,” the wrinkle was O (very small wrinkle negligible in quality), and otherwise, the wrinkle was x (noticeable wrinkle).
That is, in this example, if a 270 MPa grade steel sheet was used as the blank, the wrinkle evaluation had no problem; however, necking occurred at an end portion of the vertical wall portion. If any of 590, 980, and 1180 MPa grade steel sheets with high strengths was used as the blank, a crack was generated in an end portion of the vertical wall portion, and hence a wrinkle was generated in the vertical wall portion. If an aluminum alloy sheet was used as the blank, the wrinkle evaluation had no problem; however, a crack was generated in an end portion of the vertical wall portion.
<Sample No. 11-2>
The curved channel part 4 shown in
In this example, the stamping step was executed by using a blank heated at 300° C.
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was x (crack in vertical wall portion). If the material of the used blank was “1180,” the wrinkle was x (noticeable wrinkle), and otherwise, the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 12-1>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, in the case of the sample No. 10-1, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 12-2>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 12-3>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 12-4>
The vertical wall portion 22 and the flange portion 24 continuous to the vertical wall portion 22 of the curved channel part 2 shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 13-1>
The vertical wall portion 42 of the curved channel part shown in
In the shear deformation step, the same die as that used for the sample No. 2-1 was used, and the arrangement distance S0 (see
Then, as shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was O (very small wrinkle negligible in quality).
<Sample No. 13-2>
The vertical wall portion 42 of the curved channel part shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 13-3>
The vertical wall portion 42 of the curved channel part shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
<Sample No. 13-4>
The vertical wall portion 42 of the curved channel part shown in
For the obtained curved channel part, a generated crack and a generated wrinkle were evaluated on the basis of Tables 2 and 3. As the result, with any of the materials of the used blank, the crack was O (no crack), and the wrinkle was ⊙ (no wrinkle at all by visual inspection).
These results are shown in Tables 4 to 6 as follows. Table 4 collectively shows the results of No. 1-1 to No. 9-2 in which the curved channel parts with the flange portions were manufactured. Table 5 collectively shows the results of No. 10-1 to No. 11-2 in which the curved channel parts without a flange portion were manufactured. Table 6 collectively shows the results of No. 12-1 to No. 13-4.
Referring to these results, the following findings are obtained.
The samples No. 1-1 to No. 4-4 each employ the method of the above-described configuration (3) or (4) as the step of forming the vertical wall portion. Accordingly, if the vertical wall portion is formed only in the shear deformation step, by employing the method of the above-described configuration (3) or (4), the curved channel part with good evaluation results for crack and wrinkle can be obtained with any of all the materials.
The samples No. 5-1 to No. 6-4 each employ, as the step of forming the vertical wall portion, the method of linearly moving the restrained outer portion in the direction at the angle (θ) being 20° or 70° (outside the range from 30° to 60°) with respect to the sheet face of the blank.
Accordingly, the wrinkle generated in the vertical wall portion in the shear deformation step could not be removed although the blank heating and/or the wrinkle stretching step was executed (No. 5-2 to 5-4, No. 6-2 to 6-4). Also, in the samples No. 6-1 to No. 6-4 with θ=70°, a crack was generated in the vertical wall portion in the shear deformation step.
However, even in these cases, instead of forming the vertical wall portion only by a shear deformation force, if the vertical wall portion is formed by causing the material to flow while a proper tensile force is applied to the portion to be the vertical wall, the curved channel part in which stretch flange deformation is restricted, hence a crack is not generated, and a wrinkle is improved can be obtained.
In each of the above-described examples, the blank was heated at 300° C. For each of <Samples No. 1-3, 1-4, 2-3, 2-4, 3-3, 3-4, 4-3, 4-4, 7-3, 7-4, 8-3, 8-4, 10-3, 10-4, 13-3, 13-4>, heating was executed with heating temperatures of 600° C., 700° C., 900° C., and 1000° C. The results similar to the above description were obtained.
The curved channel part obtained by heating the blank at 1100° C. and then executing the shear deformation step had better crack and wrinkle evaluation results than the method of related art; however, a thick oxide layer of iron called scale was formed on the surface of the formed part. The thick scale disturbs welding and electro-deposition coating, and hence a removing step of pickling, polishing, or shot blast is required. Therefore the thick scale is not desirable in view of manufacturing cost.
1 blank
11 base section of blank
11
b center portion of base section
11
a boundary-side portion of base section
12 deformation section of blank
12
a portion to be vertical wall portion of deformation section
12
b outer portion of deformation section
2 curved channel part
21 top portion
22 vertical wall portion
22
a curved portion of vertical wall portion
24 flange portion
24
a curved portion of flange portion
4 curved channel part
41 top portion
42 vertical wall portion
42
a curved portion of vertical wall portion
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-150701 | Jul 2013 | JP | national |
| 2014-115164 | Jun 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/003823 | 7/18/2014 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/008495 | 1/22/2015 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 7654124 | Knaup | Feb 2010 | B2 |
| 20080053184 | Knaup | Mar 2008 | A1 |
| 20090049886 | Okuzumi et al. | Feb 2009 | A1 |
| 20120297853 | Tanaka et al. | Nov 2012 | A1 |
| 20130239645 | Tanaka et al. | Sep 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 101014428 | Aug 2007 | CN |
| 101018627 | Aug 2007 | CN |
| 102791396 | Nov 2012 | CN |
| 19853130 | May 2000 | DE |
| 1787737 | May 2007 | EP |
| 1790422 | May 2007 | EP |
| 2001-314918 | Nov 2001 | JP |
| 2002-001445 | Jan 2002 | JP |
| 2008-055511 | Mar 2008 | JP |
| 2009045653 | Mar 2009 | JP |
| 2009-160655 | Jul 2009 | JP |
| 2013-013907 | Jan 2013 | JP |
| 20050094894 | Sep 2005 | KR |
| 2012070623 | May 2012 | WO |
| Entry |
|---|
| May 19, 2015 Notice of Allowance issued in Japanese Patent Application No. 2014-559970. |
| Jun. 20, 2017 Office Action issued in Chinese Patent Application No. 201480040343.9. |
| Jun. 13, 2016 Extended European Search Report issued in European Application No. 14826390.8. |
| Oct. 21, 2014 Search Report issued in International Application No. PCT/JP2014/003823. |
| Oct. 9, 2016 Office Action issued in Chinese Patent Application No. 201480040343.9. |
| Sep. 12, 2017 Office Action issued in Korean Patent Application No. 10-2016-7000477. |
| Number | Date | Country | |
|---|---|---|---|
| 20160158821 A1 | Jun 2016 | US |
