JP2004237310A - Apparatus and method for hydrostatic forming - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for hydrostatic forming which gives a superb productivity. <P>SOLUTION: The hydrostatic forming apparatus comprises a metal die having an upper die 30 and a lower die 35 to pinch and clamp a preparatorily formed work 10 that is composed of plates 11, 15 in piles of at least two with pressured liquid inlets 18, 19 to inject a forming medium, injection means 41, 51 to provide the forming medium into the preparatorily formed work 10 through the pressured liquid inlets 18, 19, a plurality of pressure generation devices 60, 70 with different characteristics, hydraulic circuits 65, 75 connected with both the injection means 41, 51 and the pressure generation devices 60, 70 to convey the forming medium and a switching means 90 that switches the pressure generation devices to be used for supply of the forming medium according to forming progress of the preparatorily formed work 10. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic forming apparatus and a hydraulic forming method.
[0002]
[Prior art]
In a conventional hydraulic forming apparatus, a high-pressure forming medium is injected into a preform made of two metal plates joined at edges, thereby causing the preform to swell and deform to form a complicated shape. A molded article has been obtained (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-96116
[0004]
[Problems to be solved by the invention]
However, the conventional hydraulic forming apparatus has a pressure generator corresponding to the final hydraulic pressure. Since the final hydraulic pressure is high, the discharge flow rate of the pressure generator per unit time is limited.
[0005]
Therefore, the time required from the initial stage to the intermediate period, which requires a large amount of forming medium to swell and deform the preform, becomes extremely long. For this reason, for example, the tact time calculated by dividing the operation time by the number of products to be produced becomes long, and there is a problem that productivity is reduced.
[0006]
The present invention has been made in order to solve the problems associated with the above-described conventional technology, and has as its object to provide a hydraulic forming apparatus and a hydraulic forming method having good productivity.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 for achieving the above object,
A mold having an upper mold and a lower mold for sandwiching and clamping a preform having at least two sheet materials and having a hydraulic pressure injection portion into which a molding medium is injected,
Injection means for supplying a forming medium to the preform by way of a hydraulic injection unit,
A plurality of pressure generating devices having different characteristics;
A hydraulic circuit connected to the injection means and the pressure generating device, through which a molding medium flows;
Switching means for switching a pressure generating device used to supply a forming medium, according to the forming progress of the preformed body;
It is a hydraulic forming apparatus characterized by having.
[0008]
The invention according to claim 9 for achieving the above object is as follows.
A hydraulic forming method using a plurality of pressure generating devices having different characteristics,
A preformed body comprising at least two superposed plate members and having a hydraulic pressure injection part into which a forming medium is injected is sandwiched and clamped by a mold having an upper mold and a lower mold,
According to the molding progress of the preform, switch the pressure generator used to supply the molding medium,
The forming medium from the switched pressure generating device is passed through a hydraulic circuit connected to the pressure generating device and an injection unit for supplying the forming medium via the hydraulic pressure injection unit. Supply to hydraulic injection part of preform
A hydroforming method characterized by the following.
[0009]
【The invention's effect】
The present invention configured as described above has the following effects.
[0010]
According to the first aspect of the present invention, by switching the pressure generating device to be used, a characteristic suitable for securing the pressure and flow rate of the forming medium required according to the forming progress of the preform. Can be used as appropriate. Therefore, compared to the case of using a pressure generating device having a single characteristic, the tact time can be shortened and high productivity can be obtained. That is, it is possible to provide a hydraulic forming apparatus having good productivity.
[0011]
According to the ninth aspect of the present invention, by switching the pressure generating device to be used, characteristics suitable for securing the pressure and flow rate of the forming medium required according to the forming progress of the preformed body. A pressure generating device having the following is appropriately used. Therefore, compared to the case where a pressure generating device having a single characteristic is used, the tact time is shortened, and high productivity is obtained. That is, it is possible to provide a hydroforming method having good productivity.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a perspective view illustrating a molded article 20 according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view illustrating a preformed body 10 according to the molded article 20.
[0014]
The molded article 20 is, for example, an automobile structural member, and is obtained by hydraulically molding the preform 10. The preform 10 is composed of at least two plate materials 11 and 15 which are overlapped, and has a pair of hydraulic pressure injection portions 18 and 19 into which a forming medium is injected. The plate members 11 and 15 are made of, for example, a 1.8 mm steel plate and have a material strength of 440 MPa.
[0015]
The periphery of the ends of the plate materials 11 and 15 has joints 16 and 17. The joints 16 and 17 are formed on the entire periphery by, for example, laser welding, arc welding, or an adhesive, and airtightness is secured.
[0016]
FIG. 3 is a cross-sectional view for explaining the hydraulic forming apparatus according to Embodiment 1 of the present invention. The hydraulic forming apparatus according to the first embodiment includes molds 30 and 35, shaft pressing punches 40 and 50, shaft pressing cylinders 45 and 55, a pair of pressure generating devices 60 and 70 having different characteristics, and a pressure generating device 60, 70, a hydraulic circuit through which the molding medium flows, and a control device 90.
[0017]
The molds 30 and 35 are composed of an upper mold and a lower mold for clamping the preform 10 therebetween. The upper mold 30 and the lower mold 35 can be approached and separated from each other, and cavities 31 and 36 corresponding to the outer shape of the molded product 20 are formed.
[0018]
The shaft pressing punches 40 and 50 are arranged on the side surfaces of the upper die 30 and the lower die 35 and are connected to the shaft pressing cylinders 45 and 55. The axial pressing punches 40 and 50 are provided with a pair of injection nozzles (injection means) 41 and 51 for supplying a forming medium to the preform 10 via the hydraulic pressure injection sections 18 and 19 of the preform 10. Is formed. The injection nozzles 41 and 51 correspond to the hydraulic injection sections 18 and 19.
[0019]
The shaft pushing cylinders 45 and 55 support the shaft pushing punches 40 and 50 in a mold so as to be able to advance and retreat. The drive source of the shaft pushing cylinders 45 and 55 is, for example, hydraulic or pneumatic. The shaft pushing cylinders 45 and 55 are freely operated by control means 46 and 56. The control means 46 and 56 are, for example, electromagnetic valves.
[0020]
The pressure generating device 60 is constituted by a pressure-intensifying cylinder, and the secondary piston area 62 is set to be sufficiently larger than the primary piston area 61. Therefore, the pressure generating device 60 has characteristics suitable for supplying a large amount of a relatively low-pressure molding medium. The pressure generating device 60 is operated, for example, by a control unit 63 having an electromagnetic valve.
[0021]
The pressure generating device 70 is constituted by a pressure-intensifying cylinder, and the secondary piston area 72 is set sufficiently smaller than the primary piston area 71. Therefore, the pressure generator 70 has a small flow rate per unit time, but has characteristics suitable for supplying a high-pressure molding medium. Further, the pressure generating device 70 is operated, for example, by control means 73 having an electromagnetic valve.
[0022]
The pressure generating devices 60 and 70 are arranged on the side where the injection nozzles 41 and 51 are provided. Therefore, the structure of the device (die) can be simplified. Note that the pressure generating devices 60 and 70 are not limited to being constituted by pressure-increasing cylinders.
[0023]
The hydraulic circuit has hydraulic passages 65 and 75. The hydraulic passage 65 is connected to the injection nozzle 41 of the axial pushing punch 40, while a check valve 66, a low-pressure pressure generating device (one of the pressure generating devices) 60, a check valve 66, a pump 67, and a molding. The medium tanks 68 are connected in order.
[0024]
The hydraulic passage 75 extends from the injection nozzle 51 of the axial pushing punch 50 and is connected to a high-pressure pressure generator (the other pressure generator) 70 and a forming medium tank 78 via a switching valve 77. Between the injection nozzle 51 of the axial pushing punch 50 and the switching valve 77, a pressure detecting means 76 for detecting the pressure of the forming medium is arranged.
[0025]
The switching valve 77 is used to switch the pressure generating device used to supply the forming medium when the pressure detected by the pressure detecting means 76 reaches the set pressure. The switching valve 77 is also used for extracting (removing) the high-pressure forming medium and for efficiently discharging the air existing inside the hydraulic passages 65 and 75 and the preform 10.
[0026]
When discharging air, for example, the hydraulic pressure passage 75 is connected to the forming medium tank 78 by the switching valve 77. Then, the pump 67 is operated to supply the forming medium to the inside of the preformed body 10 via the hydraulic pressure passage 65 and the injection nozzle 41 of the axial pushing punch 40. The forming medium discharges the air present therein to the forming medium tank 78 via the injection nozzle 51 of the axial pushing punch 50 and the hydraulic passage 75.
[0027]
That is, the air existing inside the hydraulic circuits 65 and 75 and the preform 10 can be easily removed. In this case, the filling of the molding medium becomes smoother, and the quality of the molded product is improved.
[0028]
The control device 90 is connected to the control means 46, 56, 63, 73, the switching valve 77, and the pressure detection means 76, and controls the hydraulic circuits 65, 75, as well as the shaft pushing cylinders 45, 55 and the pressure increase. The cylinders 60 and 70 are freely operated. That is, the control device 90 has a function as a switching unit for switching the pressure generating device used for supplying the forming medium according to the forming progress of the preform 10.
[0029]
Therefore, by switching the pressure generating device to be used, a pressure generating device having characteristics suitable for securing the pressure and flow rate of the forming medium required according to the forming progress of the preform 10 is appropriately changed. Can be used.
[0030]
For example, in a process in which the pressure of the forming medium is low (for example, at the initial stage when the swelling deformation rapidly proceeds), the pressure generating device 60 having characteristics suitable for supplying a large amount of low-pressure forming medium is operated. . In a process in which the pressure of the forming medium becomes high (for example, after the intermediate period), the flow rate that can be supplied per unit time is small, but the pressure generating device 70 has characteristics suitable for supplying a high-pressure forming medium. Activate
[0031]
In this case, the required time from the initial period to the intermediate period can be shortened. Therefore, compared to the case of using a pressure generating device having a single characteristic, the tact time can be shortened and high productivity can be obtained. In addition, good shape and dimensional accuracy of the molded product can be obtained, and the quality of the molded product can be ensured.
[0032]
Further, the control device 90 acquires the pressure information of the forming medium from the pressure detecting means 76. Therefore, by detecting the pressure of the forming medium, the progress of forming the preformed body 10 can be accurately monitored, so that an optimal pressure generating device can be selected.
[0033]
Next, a hydraulic forming method using the hydraulic forming apparatus according to the first embodiment will be described. 4 is a cross-sectional view for explaining the mold clamping of the mold, FIG. 5 is a cross-sectional view for explaining the pressing of the axial pressing punch, and FIG. 6 shows a state at the end of the hydroforming. It is sectional drawing.
[0034]
In the present hydraulic forming method, the pressure generating device used to supply the forming medium is switched according to the forming progress of the preformed body, and the forming medium from the switched pressure generating device is subjected to the pressure generation. It is supplied to the hydraulic injection part of the preform via a hydraulic circuit connected to the device and to the injection means for supplying the forming medium via the hydraulic injection part.
[0035]
More specifically, first, the preform 10 shown in FIG. 1 is sandwiched and clamped by a mold having an upper mold 30 and a lower mold 35 (see FIG. 4).
[0036]
Next, the control device 90 drives the axial pushing cylinders 45 and 55 to push the axial pushing punches 40 and 50 toward the mold (see FIG. 5). The hydraulic pressure injection portions 18 and 19 of the preform 10 are expanded by the axial pressing punches 40 and 50 and the expansion is regulated by the upper die 30 and the lower die 35. For this reason, the hydraulic pressure injection portions 18 and 19 of the preform 10 are in close contact with the shaft pushing punches 40 and 50 to form the seal portion 12 and the airtightness of the preform 10 is ensured.
[0037]
Thereafter, the control device 90 opens the switching valve 77 to the forming medium tank 78 side, operates the pump 67, and supplies the forming medium to the inside of the preform 10 via the injection nozzle 41. As a result, the air present inside the hydraulic circuits 65 and 75 and the preformed body 10 is efficiently discharged to the forming medium tank 78 by the supplied forming medium.
[0038]
Then, the control device 90 activates the low-pressure pressure generating device 60 and closes the switching valve 77. In this case, the time required in the process in which the pressure of the molding medium is low is reduced. Therefore, the tact time is reduced, and high productivity is obtained. In addition, since the air existing inside the hydraulic circuits 65 and 75 and the preformed body 10 is discharged, the filling of the forming medium becomes smoother, and the quality of the formed product is improved.
[0039]
Next, when the pressure of the molding medium detected by the pressure detecting means 76 reaches a predetermined pressure, the control device 90 switches the switching valve 77 to the pressure generating device 70 side to operate the pressure generating device 70. The pressure generator 70 injects a high-pressure molding medium into the inside of the preform 10 and applies a final hydraulic pressure.
[0040]
In other words, in the process where the pressure of the molding medium becomes high, the flow rate that can be supplied per unit time is small, but the pressure generating device 70 having characteristics suitable for supplying the high-pressure molding medium is operated. Therefore, good shape and dimension accuracy of the molded product can be obtained, and the quality of the molded product can be secured.
[0041]
As described above, by switching the pressure generating device to be used, a pressure generating device having characteristics suitable for securing the pressure and flow rate of the forming medium required according to the forming progress of the preform is provided. Are used as appropriate. Therefore. Compared to the case of using a pressure generator having a single characteristic, the tact time is shortened and high productivity is obtained.
[0042]
Thereafter, the preform 10 is bulged to a shape corresponding to the cavities 31, 36 of the upper mold 30 and the lower mold 35 corresponding to the outer shape of the molded product 20, and the hydraulic molding is completed (see FIG. 6). . The control device 90 operates the switching valve 77 to extract the high-pressure forming medium. After the pressure is released, the mold is opened, and the obtained molded product 20 is taken out of the mold, and the hydraulic pressure injection portions 18 and 19 formed at both ends are appropriately cut off.
[0043]
Next, the relationship between the pressure and the flow rate of the molding medium will be described in detail. 7 (A) to 7 (D) are cross-sectional views for explaining the start, the initial stage, the intermediate period, and the end of the hydroforming, and FIG. 5 is a graph showing changes over time in pressure and flow rate of a medium.
[0044]
From the state at the start shown in FIG. 7 (A), the initial stage in which the bulging deformation of the preformed body 10 shown in FIG. 7 (B) progresses rapidly, and the preformed body 10 shown in FIG. Until the apex 13 of the bulging portion reaches an intermediate period (hydraulic pressure P1) in which it contacts the cavities 31 and 36 of the upper mold 30 and the lower mold 35 first, as shown in the graph of FIG. The flow rate of the molding medium is large.
[0045]
Then, after the intermediate period shown in FIG. 7 (C), as the area of the preform 10 in contact with the cavities 31, 36 of the upper mold 30 and the lower mold 35 increases, the required hydraulic pressure becomes While increasing from P1 (eg, 10 MPa) to P2 (eg, 25 MPa), the required flow rate of the forming medium is relatively reduced. Then, the hydraulic pressure rises sharply from around P2.
[0046]
Thereafter, the hydraulic pressure rises to a final hydraulic pressure P3 (for example, 120 MPa) necessary for molding the vicinity 32 of the corners of the cavities 31 and 36 (a radius of curvature of the corner of the molded product is obtained), and the preformed body 10 , Molded into the final product shape.
[0047]
Since the pressure and the flow rate of the molding medium have the above-described relationship, in the process where the pressure of the molding medium is low, the pressure generating device 60 is operated to set the filling time of the molding medium and the pressure generating device 70 to operate. It can be greatly reduced compared to the case.
[0048]
In the process in which the pressure of the forming medium becomes high, by switching from the low-pressure large-flow pressure generating device 60 to the high-pressure pressure generating device 70 capable of generating a high pressure as compared with the pressure generating device 60, a favorable pressure is obtained. Shape and dimensional accuracy can be obtained. That is, the tact time can be reduced while ensuring the quality of the molded product.
[0049]
The set pressure for switching the pressure generating device may be, for example, the liquid pressure shown in FIG. 7 (C) which is necessary for contact between the bulging and deformed preform and a portion other than at least near the corner of the mold. Pressure) P1. However, the set pressure is not limited to the hydraulic pressure P1, and it is also possible to select a hydraulic pressure (for example, 20 MPa) between the hydraulic pressures P1 and P2.
[0050]
Further, the switching of the pressure generating device is not limited to the one based on the detection result of the pressure of the forming medium. For example, by providing a distance sensor or the like inside the mold, the forming progress of the preform 10 is directly detected. It can also be performed by doing so.
[0051]
As described above, in the first embodiment, the tact time is shortened and high productivity is obtained as compared with the case where a pressure generating device having a single characteristic is used. That is, a hydraulic forming apparatus and a hydraulic forming method having good productivity can be provided. In addition, the first embodiment can be easily applied to a preform having a pair of hydraulic injection portions.
[0052]
FIG. 9 is a cross-sectional view for explaining a preform and a hydraulic forming apparatus according to Embodiment 2 of the present invention. FIG. 10 is an enlarged cross-sectional view of a main part of the hydraulic forming apparatus shown in FIG. FIG. 11 is a cross-sectional view showing a state at the end of the hydroforming.
[0053]
Preformed body 110 according to the second embodiment differs from preformed body 10 according to the first embodiment in that it has a single hydraulic pressure injection portion 114. The hydraulic pressure injection unit 114 has a dome shape, and an opening 118 is formed in a portion of the plate 115 located below the hydraulic pressure injection unit 114. Further, a hydraulic channel 119 is formed at a portion of the plate members 111 and 115 adjacent to the hydraulic injection unit 114. Reference numerals 116 and 117 are joints for maintaining airtightness at the edges.
[0054]
The hydraulic forming apparatus according to the second embodiment is connected to dies 130, 135, nozzle section 180, a pair of pressure generating apparatuses 160, 170 having different characteristics, and pressure generating apparatuses 160, 170, and the liquid in which the forming medium flows. It has a pressure circuit and a control device 190.
[0055]
The dies 130 and 135 are composed of an upper die and a lower die for clamping the preform 110 by clamping. In the upper mold 130 and the lower mold 135, cavities 131 and 136 corresponding to the outer shape of the molded product 120 are formed.
[0056]
The upper die 130 has a concave portion 134 corresponding to the hydraulic pressure injection portion 114 of the preformed body 110 and a concave groove 133 corresponding to the hydraulic passage 119 of the preformed body 110. The lower mold 135 has a concave portion 137 in which the nozzle portion 180 is arranged. The nozzle part 180 can be inserted into the opening part 118 of the plate material 115.
[0057]
The nozzle portion 180 is a single injection means corresponding to the hydraulic pressure injection portion 114 of the preform 110, and has a passage 181 through which a forming medium extending through the inside of the lower mold 135 flows. .
[0058]
The pressure generating device 160 is constituted by a pressure-intensifying cylinder whose secondary-side piston area 162 is set to be sufficiently larger than the primary-side piston area 161 and has characteristics suitable for supplying a large amount of low-pressure molding medium. . The pressure generating device 160 is operated by, for example, a control unit 163 having an electromagnetic valve.
[0059]
The pressure generating device 170 is constituted by a pressure-intensifying cylinder whose secondary piston area 172 is set to be sufficiently smaller than the primary piston area 171. Although the flow rate that can be supplied per unit time is small, a high-pressure molding medium is used. Has properties suitable for supply. The pressure generator 170 is operated by, for example, a control unit 173 having an electromagnetic valve.
[0060]
Further, since the pressure generating devices 160 and 170 are arranged on the side where the nozzle portion 180 is provided, the structure of the device (die) can be simplified.
[0061]
The hydraulic circuit has a hydraulic passage 165. The hydraulic pressure passage 165 is connected to a passage 181 extending from the nozzle portion 180, and on the other hand, a pressure detecting means 176, a high-pressure pressure generating device 170, a check valve 166, a low-pressure pressure generating device 160, a check valve 166, The pump 167 and the forming medium tank 168 are connected in order.
[0062]
Unlike the first embodiment, it is not necessary to use a switching valve to switch between the pressure generating devices 60 and 70. Due to the presence of the check valves 166 and 166, when the pressure generating device 70 is used, the pressure generating device 60 The circuit is shut off.
[0063]
Further, a branch 165A is provided between the passage 181 and the pressure detecting means 176, and a switching valve 177 is connected. The switching valve 177 is connected to the forming medium tank 178. The switching valve 177 is used for extracting (releasing) the high-pressure forming medium.
[0064]
The control unit 190 is connected to the control units 163 and 173, the pressure detection unit 176, and the switching valve 177, and operates the pressure generation units 160 and 170 based on the pressure of the forming medium detected by the pressure detection unit 176. Let it.
[0065]
That is, the control device 190 has a function as a switching unit for switching the pressure generating device used for supplying the forming medium in accordance with the forming progress of the preformed body 110.
[0066]
Therefore, in the process where the pressure of the forming medium is low (for example, in the initial stage), the pressure generator 160 for low pressure is operated, and in the process where the pressure of the forming medium becomes high (for example, after the intermediate period), the high pressure is generated. By operating the pressure generating device 170, the initial required time is shortened, the tact time is shortened, and high productivity can be obtained. In addition, good shape and dimensional accuracy of the molded product can be obtained, and the quality of the molded product can be ensured.
[0067]
Further, the control device 190 acquires the pressure information of the molding medium from the pressure detection unit 176. Therefore, by detecting the pressure of the forming medium, the progress of the forming of the preformed body can be accurately monitored, so that it is possible to select an optimum pressure generating device.
[0068]
Next, a hydraulic forming method using the hydraulic forming apparatus according to the second embodiment will be described. FIG. 11 is a cross-sectional view showing the state at the end of the hydroforming.
[0069]
First, the preform 110 is sandwiched and clamped by a mold having an upper mold 130 and a lower mold 135. As a result, the hydraulic pressure injection portion 114 and the hydraulic pressure channel 119 of the preform 110 are positioned in the concave portion 134 and the concave groove 133 of the upper die 130, while the opening portion 118 of the preform 110 has the nozzle portion 180. Is inserted and airtightness is ensured.
[0070]
Next, the control device 190 operates the pump 167 to fill the forming medium into the hydraulic pressure passage 165 and the passage 181, and then closes the switching valve 177. Then, the control device 190 operates the pressure generating device 160 and injects a relatively low-pressure, large-flow molding medium into the flat preform 110. In this case, the time required in the process in which the pressure of the molding medium is low is reduced. Therefore, the tact time is reduced, and high productivity is obtained.
[0071]
Next, when the pressure of the molding medium detected by the pressure detecting means 176 reaches a predetermined value, the control device 190 stops the operation of the pressure generating device 160 and operates the pressure generating device 170. The pressure generator 170 injects a high-pressure molding medium into the inside of the preform 110 and applies a final hydraulic pressure.
[0072]
In other words, in the process in which the pressure of the molding medium becomes high, the flow rate that can be supplied per unit time is small, but the pressure generating device 170 having characteristics suitable for supplying the high-pressure molding medium is operated. When switching from the pressure generating device 160 to the pressure generating device 170, the circuit on the pressure generating device 60 side is shut off due to the presence of the check valves 166 and 166. Therefore, good shape and dimension accuracy of the molded product can be obtained, and the quality of the molded product can be secured.
[0073]
Thereafter, the preform 110 is bulged to a shape corresponding to the cavities 31, 36 of the upper die 130 and the lower die 135 corresponding to the outer shape of the molded product 120, and the hydraulic forming is completed (see FIG. 11). .
[0074]
Next, the control device 190 operates the switching valve 177 to extract the high-pressure forming medium. After the pressure is released, the mold is opened, and the obtained molded article 120 is taken out of the mold, and the hydraulic pressure injection portion 118 formed at one end is appropriately cut off.
[0075]
As described above, also in the second embodiment, the takt time is shortened and high productivity is obtained as compared with the case where a pressure generating device having a single characteristic is used. That is, a hydraulic forming apparatus and a hydraulic forming method having good productivity can be provided. In addition, the second embodiment is easy to apply to a preformed body having a single hydraulic pressure injection part, for example, a small component, and the structure of the device is simplified.
[0076]
Note that the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the claims.
[0077]
For example, it is possible to apply three or more pressure generating devices having different characteristics according to the necessity of a preform or a molded product. In this case, the pressure generator can be switched a plurality of times in accordance with the progress of molding of the preform, so that the pressure and liquid volume of the molding medium can be more precisely controlled.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a molded product according to a first embodiment of the present invention.
FIG. 2 is a perspective view for explaining a preform according to the molded product shown in FIG. 1;
FIG. 3 is a cross-sectional view for explaining the hydraulic forming apparatus according to Embodiment 1 of the present invention.
FIG. 4 is a cross-sectional view for explaining mold clamping.
FIG. 5 is a cross-sectional view for explaining pushing of a shaft pushing punch.
FIG. 6 is a cross-sectional view showing a state at the end of hydroforming.
FIGS. 7A to 7D are cross-sectional views for explaining a start, an initial stage, an intermediate period, and an end of hydraulic forming.
FIG. 8 is a graph showing changes over time in pressure and flow rate of a forming medium due to progress of bulging deformation of a preform.
FIG. 9 is a cross-sectional view for explaining a preform and a hydraulic forming apparatus according to Embodiment 2 of the present invention.
FIG. 10 is an enlarged sectional view of a main part of the hydraulic forming apparatus shown in FIG.
FIG. 11 is a cross-sectional view showing a state at the end of hydroforming.
[Explanation of symbols]
10: Preformed body,
11 ... board material,
12 ... seal part,
13 ... the vertex,
15 ... board material,
16, 17 ... joint,
18, 19 ... hydraulic pressure injection part,
20: molded product,
30 ... upper mold (mold),
31 ... cavity,
32 ... near the corner,
35 ... Lower mold (mold)
36 ... cavity,
40 ... Axial punch,
41 ... injection nozzle,
45 ... Axle pushing cylinder,
46 ... control means,
50 ... Axial punch,
51 ... hydraulic injection part,
55 ... Axle pushing cylinder,
56 ... control means,
60 ... pressure generator,
61 ... primary side piston area,
62: secondary piston area,
63 ... control means,
65 ... hydraulic passage,
66 ... check valve,
67… pump,
68 ... forming medium tank,
70 ... Pressure generator,
71: Primary piston area,
72 ... secondary piston area,
73 ... control means,
75 ... hydraulic passage,
76 ... pressure detecting means,
77 ... Switching valve,
78 molding medium tank,
90 ... control device (switching means)
110 ... preform,
111 ... plate material,
114 ... hydraulic injection part,
115 ... plate material,
116, 117 ... joint,
118 ... opening,
119 ... hydraulic flow path,
120: molded product,
130 ... upper mold (mold),
131 ... cavity
133 ... groove,
134 ... recess,
135 ... Lower mold (mold),
136 ... cavity,
137: recess,
160 ... pressure generating device,
161: primary piston area,
162: secondary piston area,
163: control means,
165: hydraulic passage,
165A ... branch part,
166 ... check valve,
167 ... pump,
168: forming medium tank,
170 ... pressure generating device,
171: primary piston area,
172: secondary piston area,
173 ... control means,
176 ... pressure detecting means,
177 ... Switching valve,
178: molding medium tank,
180 ... nozzle part,
181 ... passage,
190 ... control device (switching means)
P1, P2, P3 ... hydraulic pressure.

Claims (11)

A mold having an upper mold and a lower mold for sandwiching and clamping a preform having at least two sheet materials and having a hydraulic pressure injection portion into which a molding medium is injected,
Injection means for supplying a forming medium to the preform by way of a hydraulic injection unit,
A plurality of pressure generating devices having different characteristics;
A hydraulic circuit connected to the injection means and the pressure generating device, through which a molding medium flows;
Switching means for switching a pressure generator used for supplying a forming medium in accordance with the progress of forming the preformed body. Having pressure detection means for detecting the pressure of the molding medium,
2. The hydraulic forming apparatus according to claim 1, wherein the switching unit switches the pressure generator when the detected pressure reaches a set pressure. The said set pressure is a pressure required for the site | part other than at least a corner | angular part vicinity of the said metal mold | die, and the bulging deformed preform to contact. Hydraulic forming equipment. The hydraulic pressure forming device according to any one of claims 1 to 3, wherein the pressure generating device is configured by a pressure increasing cylinder. The hydraulic pressure forming apparatus according to any one of claims 1 to 4, wherein the pressure generating device is disposed on a side where the injection unit is provided. The preform has a pair of hydraulic injection parts,
The injection means comprises a pair of injection means corresponding to the hydraulic injection section,
6. The hydraulic forming apparatus according to claim 5, wherein the pressure generating device includes a pair of pressure generating devices arranged on a side where the injection unit is arranged. In the hydraulic circuit connected to one of the pressure generating devices, a pump for supplying a forming medium is disposed, and in the hydraulic circuit connected to the other of the pressure generating devices, a pump for discharging the forming medium is provided. 7. The hydraulic forming apparatus according to claim 6, wherein the switching valve is disposed. The preform has a single hydraulic injection part, the injection means comprises a single injection means corresponding to the hydraulic injection part, and the pressure generating device includes the injection means. The hydraulic forming apparatus according to claim 5, wherein the hydraulic forming apparatus is arranged on all sides. A hydraulic forming method using a plurality of pressure generating devices having different characteristics,
A preformed body comprising at least two superposed plate members and having a hydraulic pressure injection part into which a forming medium is injected is sandwiched and clamped by a mold having an upper mold and a lower mold,
According to the molding progress of the preform, switch the pressure generator used to supply the molding medium,
The forming medium from the switched pressure generating device is passed through a hydraulic circuit connected to the pressure generating device and an injection unit for supplying the forming medium via the hydraulic pressure injection unit. A hydraulic forming method comprising supplying the preformed body to a hydraulic pressure injection section. 10. The hydraulic forming method according to claim 9, wherein the pressure of the forming medium is detected, and the pressure generating device is switched when the detected pressure reaches a set pressure. The said set pressure is a pressure required for the site | part other than at least a corner part of the said metal mold | die, and the bulging deformed preform to contact. Hydraulic molding method.

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