Stretch molding equipment

Abstract

To provide a stretch molding device which can discharge a sufficient amount of a lubrication oil to a workpiece not only when a temperature of the lubricant is high but also when an air temperature is low.SOLUTION: A stretch molding device 1 includes: a sandwiching mechanism 2 which sandwiches one portion of a plate-like workpiece W; a pulling mechanism 4 which pulls the other portion of the workpiece W in a state that the workpiece W is sandwiched by the sandwiching mechanism 2; a molding part 3 which molds the workpiece W between the sandwiching mechanism 2 and the pulling mechanism 4; discharge parts 61 which are disposed at both surface sides of the workpiece W on a side of the sandwiching mechanism 2 opposite to the pulling mechanism 4 and discharge a lubricant L to the respective surfaces of the workpiece W; and heating mechanisms 9 which are provided at the discharge parts 61 and heat the lubricant L.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a stretch forming apparatus. [Background technology]

[0002] For example, when manufacturing an aircraft frame or a reflecting surface of a parabolic antenna, a plate-shaped workpiece made of metal or the like is formed into a curved surface. As described above, a stretch forming apparatus is known as an apparatus for forming a plate-shaped workpiece into a curved surface.

[0003] For example, in the stretch forming device described in Patent Document 1, the workpiece is clamped by a clamping mechanism from a direction perpendicular to the workpiece, and the leading end of the workpiece is pulled. Then, a curved mold is pressed against the part of the workpiece being pulled, and the workpiece is pulled in that state, thereby forming the plate-shaped workpiece into a curved surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 4-300033 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in stretch forming devices, in order to reduce friction between the workpiece and the clamping mechanism when the workpiece is clamped and pulled by the clamping mechanism, the device may be configured to inject lubricating oil onto the front and back surfaces of the workpiece before the workpiece is clamped by the clamping mechanism. In this case, the discharge parts are brought into contact with or close to the front and back surfaces of the workpiece, respectively, and the lubricating oil is discharged onto the front and back surfaces of the workpiece by allowing the lubricating oil to flow between each surface of the workpiece and each discharge part.

[0006] Furthermore, a high viscosity lubricant is used so that the lubricant remains attached to the surface of the workpiece even when the workpiece is clamped at high pressure by the clamping mechanism. However, when temperatures are low in winter, high-viscosity lubricating oils can solidify or lose fluidity inside the nozzle or oil reservoir of the discharge section, making it impossible to discharge a sufficient amount of lubricant onto the workpiece.

[0007] If a sufficient amount of lubricating oil is not dispensed onto the workpiece, the surface of the workpiece may be damaged or may become seized when the workpiece is clamped at high pressure by the clamping mechanism. The present invention has been made in consideration of the above points, and aims to provide a stretch forming device that can eject a sufficient amount of lubricating oil onto the workpiece, not only when the temperature of the lubricant is high, but also when the air temperature is low. [Means for solving the problem]

[0008] The stretch forming device according to the present invention comprises: a clamping mechanism that clamps a portion of a plate-shaped workpiece; a pulling mechanism that pulls another portion of the workpiece while the workpiece is clamped by the clamping mechanism; a forming unit that forms the workpiece between the clamping mechanism and the pulling mechanism; Discharge units disposed on both sides of the workpiece on the opposite side of the clamping mechanism from the pulling mechanism, and configured to discharge lubricant onto each surface of the workpiece; a heating mechanism provided in the discharge portion for heating the lubricant; [Effects of the Invention]

[0009] According to the present invention, it is possible to discharge a sufficient amount of lubricating oil onto a workpiece not only when the temperature of the lubricant is high but also when the ambient temperature is low. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1A is an image diagram for explaining the stretch forming device according to the present embodiment, and FIG. 1B is an image diagram as seen from the side. [Figure 2] FIG. 1A is a perspective view showing an example of a compound curved surface formed on a workpiece, and FIG. 1B is a side view. [Figure 3] 1 is a schematic side view showing the configuration of a stretch molding device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing the overall configuration of the discharge mechanism of the stretch molding device according to the present embodiment. [Figure 5] FIG. 2 is a front view of a main part of the discharge mechanism. [Figure 6] FIG. 2A is a side cross-sectional view of a main part of the discharge mechanism, and FIG. 2B is a side cross-sectional view showing a state in which the nozzle of the discharge part is open. [Figure 7] FIG. 2 is a view of a portion including the lower surface of the first discharge portion as viewed from below, i.e., from the workpiece side. [Figure 8] (a) is a view from below of an ejection section in which only a plurality of nozzles are formed, and (b) is a view showing the state in which lubricant has been applied only to the part of the workpiece facing the nozzles. [Figure 9] FIG. 1 is a diagram showing the overall configuration of a discharge mechanism of a conventional stretch molding device. [Figure 10] FIG. 3 is a plan cross-sectional view of the discharge portion according to the present embodiment, illustrating the flow of lubricant within the discharge portion. [Figure 11] 10 is a graph showing an example of a change over time in the temperature of the lubricant in the discharge portion in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a stretch forming device according to the present invention will be described below with reference to the drawings. Although the case where the workpiece is a plate material having a substantially triangular shape will be described, the workpiece may have a rectangular shape or the like, and the shape of the workpiece is not limited to a substantially triangular shape.

[0012] First, the overall configuration of the stretch forming device will be described. FIG. 1(a) is an image diagram for explaining the stretch forming device according to this embodiment, and FIG. 1(b) is an image diagram seen from the side.

[0013] 1(a) and 1(b), the direction indicated by the arrow X is the direction in which the workpiece is pulled, and will be referred to as the X direction or pulling direction. The direction indicated by the arrow Y in the figures is the direction perpendicular to the pulling direction, and will be referred to as the Y direction. Furthermore, the direction indicated by the arrow Z in the figure is a direction perpendicular to the plate-shaped workpiece, and will hereinafter be referred to as the Z direction or the up-down direction.

[0014] The stretch forming device 1 includes a clamping mechanism 2 that clamps one part of the workpiece W, a pulling mechanism 4 that pulls the other part of the workpiece W in the X direction, and a forming section 3 that forms the workpiece W between the clamping mechanism 2 and the pulling mechanism 4. In the clamping mechanism 2, the workpiece W can be clamped between the first frame 21 and the second frame 22 in a direction perpendicular to the plate-shaped workpiece W, that is, in the Z direction.

[0015] In this embodiment, the lower surface of the upper mold 21a of the first frame 21 extending in the Y direction has a central portion in the X direction that protrudes downward, forming a convex portion that extends in the Y direction. G in the figure represents the downward protrusion depth of the convex portion.

[0016] In addition, the upper surface of the lower mold 22a of the second frame 22, which extends in the Y direction corresponding to the first frame 21, has a central portion in the X direction recessed downward, and a concave portion extending in the Y direction is formed corresponding to the convex portion of the upper mold 21a. In addition, the convex portion formed on the upper mold 21a of the first frame 21 and the concave portion formed on the lower mold 22a of the second frame 22 do not have to be a single line, and for example, multiple lines can be provided.

[0017] In this embodiment, the molding section 3 includes a second stage 31 extending in the Y direction and having a mold 31a at its lower end portion that is curved downwardly and convex. The second stage 31 is disposed so as to press the die 31a against the workpiece W from above.

[0018] In addition, when viewed from the clamping mechanism 2 side, the molding section 3 has a third stage 32 extending in the Y direction at the rear side of the second stage 31, and having a mold 32a at its upper end portion that is curved downwardly convexly. The third stage 32 is disposed so that the workpiece W, which has been pushed down by the second stage 31, is pushed up from below by the die 32a.

[0019] When viewed from the clamping mechanism 2 side, the workpiece W is pulled in the X direction by the pulling mechanism 4, with its end held by the clamp portion 41 of the pulling mechanism 4 located at the back side of the forming section 3. The clamping portion 41 of the pulling mechanism 4 pulls the workpiece W while gripping the end of the workpiece W and moving in the X direction, that is, in the direction away from the clamping mechanism 2.

[0020] In the stretch forming device 1, the workpiece W is clamped by the clamping mechanism 2 and pulled in the X direction by the pulling mechanism 4. The workpiece W is pressed against the dies 31a and 32a from above and below in the forming section 3 while sliding between the first frame 21 and the second frame 22 and tension is applied in the X direction.

[0021] In the stretch forming device 1 according to this embodiment, the workpiece W is formed by the forming unit 3 between the clamping mechanism 2 and the pulling mechanism 4 in this manner. By forming the workpiece W in this manner, the workpiece W is formed into a curved state in the Y direction, as shown in FIG. 2(a), for example.

[0022] Furthermore, while the workpiece W is being pulled, the distance L1 between the clamping mechanism 2 and the second stage 31 and the distance L2 between the second stage 31 and the third stage 32 are changed. Alternatively, the second stage 31 and the third stage 32 are moved up and down to change the amount by which the second stage 31 pushes the workpiece W downward and the amount by which the third stage 32 pushes the workpiece W upward.

[0023] By moving the second stage 31 and the third stage 32 in this manner, the workpiece W is formed into a curved state not only in the Y direction but also in the X direction, as shown in, for example, FIGS. 2(a) and 2(b). In this way, the stretch forming device 1 according to this embodiment is capable of forming a compound curved surface of the workpiece W having a three-dimensional curvature in the X and Y directions.

[0024] FIG. 3 is a schematic side view showing the configuration of the stretch forming device according to this embodiment. The workpiece W is placed on the conveyor 11 and inserted between the discharge portions 61A and 61B of the discharge mechanism 6 that discharge lubricant onto the upper and lower surfaces of the workpiece W, respectively, from the left side in the figure. The discharge mechanism 6 will be described in detail later.

[0025] Then, the workpiece W is inserted between the first frame 21 and the second frame 22 of the clamping mechanism 2. The first frame 21 of the clamping mechanism 2 is attached to the top of the clamping mechanism 2 by being connected to the top of the clamping mechanism 2 via a link mechanism 23 and to a lifting actuator 24 arranged above the top of the clamping mechanism 2.

[0026] The link mechanism 23 is operated by the lifting actuator 24, so that the first frame 21 can be moved in the Z direction. By moving the position of the first frame 21 in the Z direction and lowering it, the workpiece W is sandwiched between the first frame 21 and the second frame 22 as shown in FIG. 1(b).

[0027] The stretch forming apparatus 1 is also provided with a moving device 25 including a motor 25a for moving the clamping mechanism 2 in the X direction, i.e., the pulling direction. By operating the moving device 25, the entire clamping mechanism 2 can be moved in the X direction relative to the base 5 of the stretch forming apparatus 1. By moving the clamping mechanism 2 in the X direction relative to the base 5, the distance L1 between the clamping mechanism 2 and the second stage 31 shown in FIGS. 1(a) and 1(b) can be changed.

[0028] As shown in FIG. 3, the forming unit 3 is configured so that the second stage 31 can move in the Z direction. In this embodiment, the second stage 31 has a configuration similar to that of the first frame 21 of the clamping mechanism 2 and is capable of moving in the Z direction.

[0029] Furthermore, the third stage 32 of the forming unit 3 is capable of moving in the Z direction and the X direction. That is, a support base 33 is disposed below the third stage 32, and the third stage 32 can be moved in the Z direction relative to the support base 33 by driving an elevator device 34. The support base 33 is supported by a base unit 5 so as to be movable in the X direction, and can be moved in the X direction, i.e., the pulling direction of the workpiece W, relative to the base unit 5 by driving a moving device 35 equipped with a servo motor or the like.

[0030] The moving device 35 is driven to move the support base 33 in the X direction, thereby moving the third stage 32 in the X direction, thereby changing the distance L2 between the second stage 31 and the third stage 32 shown in Figures 1(a) and (b). In addition, by driving the lifting device 34 to move the third stage 32 in the Z direction, it is possible to adjust the amount by which the workpiece W is pushed upward by the third stage 32 described above.

[0031] Then, the workpiece W is clamped between the first frame 21 and the second frame 22 of the clamping mechanism 2, pushed down by the die 31a of the second stage 31, and pushed up by the die 32a of the third stage 32, and the end of the workpiece W is gripped by the clamp portion 41 of the pulling mechanism 4 at the position indicated by A in the figure. The position indicated by A in FIG. 3 will be referred to as the pulling start position A hereinafter.

[0032] The tension mechanism 4 includes a carriage 42 supported by a base 5 so as to be movable in the X direction, and the clamp 41 described above is attached to the tip of the carriage 42, that is, the end on the clamping mechanism 2 side.

[0033] A servo motor 43 is disposed on the base 5 . The rotational output of the servo motor 43 is reduced in speed by a reducer 44, output, and transmitted to a pinion 45 and a rack 46, and then transmitted to the carriage 42 via a rack-and-pinion mechanism.

[0034] In this way, the carriage 42 can travel in the X direction via the rack 46 and the travel frame 47 by the rotational drive of the servo motor 43 . When the carriage 42 moves in the X direction, the clamping portion 41 moves in the X direction, and the workpiece W is pulled in the X direction, that is, the pulling direction.

[0035] As described above, before the workpiece W starts to be formed, the end of the workpiece W is gripped by the clamp portion 41 at the pulling start position A. Then, the servo motor 43 is operated to move the clamping portion 41 in the X direction, whereby the clamping portion 41 pulls the workpiece W in the pulling direction, thereby forming the workpiece W.

[0036] Next, the discharge mechanism 6 of the stretch molding device 1 according to this embodiment will be described. 3, the discharge mechanism 6 includes a first discharge part 61A and a second discharge part 61B that are disposed on the upper and lower surfaces of the workpiece W, respectively, on the opposite side of the clamping mechanism 2 from the pulling mechanism 4. Hereinafter, the two discharge parts will be collectively referred to as discharge part 61.

[0037] FIG. 4 is a diagram showing the overall configuration of the discharge mechanism of the stretch molding device according to this embodiment. In this embodiment, the discharge mechanism 6 is made up of a supply mechanism 7, a discharge section 61, and a circulation mechanism 8.

[0038] The supply mechanism 7 includes an oil tank 62 for storing the lubricant L in the base portion 5 of the stretch forming device 1 or the like, and supplies the lubricant L from the oil tank 62 to the discharge portion 61 . One end of a supply path 63 for lubricant L to the discharge portion 61 is inserted into the oil tank 62, and the other end of the supply path 63 branches off and is connected to the first discharge portion 61A and the second discharge portion 61B, respectively.

[0039] The lubricant L is supplied by driving a pump 64 from an oil tank 62 through a supply passage 63 to the first discharge portion 61A and the second discharge portion 61B. Further, the supply path 63 is provided with a control valve 65 for allowing or blocking the flow of the lubricant L through the supply path 63.

[0040] In this embodiment, the discharge part 61 is composed of a first discharge part 61A arranged above the workpiece W and a second discharge part 61B arranged below the workpiece W. A heating mechanism 9 for heating the lubricant L is provided in each of the first discharge part 61A and the second discharge part 61B.

[0041] The first discharge part 61A and the second discharge part 61B have lubricant reservoirs 66A and 66B for storing the lubricant L, respectively, and the heating mechanism 9 is provided in each of the lubricant reservoirs 66A and 66B. In the following description, the two lubricant reservoirs will be collectively referred to as lubricant reservoir 66.

[0042] Furthermore, a plurality of nozzles 80 for discharging the lubricant L are formed in the first discharge part 61A and the second discharge part 61B at the portions facing the workpiece W, respectively. The configuration of the discharge unit 61 including the nozzle 80 will be described in detail later.

[0043] The first discharge part 61A and the second discharge part 61B are provided with temperature sensors 67 for measuring the temperatures of the lubricant L in the lubricant reservoirs 66A and 66B. An oil pan 68 is disposed below the first discharge section 61A and the second discharge section 61B to collect the lubricant L discharged from the nozzle 80, and the lubricant L after discharge passes through a drainage path 69 and is collected in a recovery tank 72, which will be described later.

[0044] On the other hand, in this embodiment, a circulation mechanism 8 for circulating the lubricant L in the lubricant reservoir 66 of the discharge part 61 is provided. Specifically, one end of a discharge passage 70 is attached to each of the first discharge part 61A and the second discharge part 61B, and each discharge passage 70 is provided with a control valve 71.

[0045] The discharge paths 70 are joined together and inserted into a recovery tank 72. When the control valve 71 is opened, the lubricant L in the lubricant reservoir 66 of the discharge part 61 is discharged into the discharge path 70 and collected in the recovery tank 72 through the discharge path 70. The lubricant L recovered in the recovery tank 72 is sucked up by driving a pump 73, and after dust and the like are removed by a removal filter 74, the lubricant L is returned to the oil tank 62. The oil tank 62 and the recovery tank 72 are each provided with a heating mechanism 75 for heating the stored lubricant L and a temperature sensor 76 for measuring the temperature of the lubricant L.

[0046] Next, the configuration of the main parts including the discharge part 61 of the discharge mechanism 6 will be described. Fig. 5 is a front view of the main parts of the discharge mechanism. Fig. 6(a) is a side cross-sectional view of the main parts of the discharge mechanism, and Fig. 6(b) is a side cross-sectional view showing the nozzle of the discharge part in an open state. Fig. 7 is a view of the part including the lower surface of the first discharge part as seen from below, i.e., from the workpiece W side.

[0047] In this embodiment, as shown in FIGS. 5 and 6(a), the first discharge part 61A and the second discharge part 61B are both formed in the shape of a housing. The lubricant reservoirs 66A and 66B formed therein are sealed and filled with the lubricant L.

[0048] In this embodiment, an actuator 77 for raising and lowering the first discharge section 61A is provided above the first discharge section 61A, and the first discharge section 61A moves up and down along guides 78 and 79 by driving the lifting actuator 77. The first discharge part 61A is lifted when the workpiece W is inserted between the first discharge part 61A and the second discharge part 61B, and is lowered to a position close to the workpiece W once the workpiece W is inserted.

[0049] Each surface of the first discharge section 61A and the second discharge section 61B that faces the workpiece W, i.e., the lower surface of the first discharge section 61A and the upper surface of the second discharge section 61B, is formed in an approximately flat shape, and multiple nozzles 80 are formed on each surface. Note that the nozzles 80 are not shown in Fig. 5. Also, Fig. 7 shows a case where a plurality of nozzles 80 are arranged in a row in the Y direction, but for example, a plurality of nozzles 80 may be arranged in a plurality of rows, and the arrangement of the nozzles 80 can be determined appropriately.

[0050] As shown in Figure 6(a), inside the lower surface of the first discharge section 61A and inside the upper surface of the second discharge section 61B, holes 81 with circular cross-sections that intersect with each nozzle 80 are drilled in a direction perpendicular to the nozzles 80, i.e., in the X direction. A cylindrical rod-shaped member 82 for opening and closing the nozzle and having the same diameter as the hole 81 is inserted into each hole 81. A groove 82a is formed in part of each cylindrical rod-shaped member 82 so that the diameter becomes smaller.

[0051] As shown in FIG. 7, the end of each rod-shaped member 82 is connected to a restricting plate 83 extending in the Y direction. Both ends of the regulating plate 83 in the Y direction are connected to translational actuators 84, and the regulating plate 83 moves parallel to the X direction when the actuators 84 are driven. Therefore, by operating the actuators 84, all of the rod-shaped members 82 move simultaneously in the X direction.

[0052] When each rod-shaped member 82 is in the position shown in FIG. 6(a), the hole 81 at the nozzle 80 is filled with the rod-shaped member 82, and the nozzle 80 is in a closed state. Therefore, in this state, the lubricant L in the lubricant reservoir 66 does not leak out through the nozzle 80 to the outside.

[0053] However, when each rod-shaped member 82 moves and the position of the groove 82a of the rod-shaped member 82 comes to the position of the nozzle 80 as shown in Figure 6(b), the lubricant L in the lubricant reservoir 66 flows out through the groove 82a to the outside. In other words, the nozzle 80 opens and the lubricant L is discharged. In this embodiment, by moving each rod-shaped member 82 in this manner, the nozzle 80 can be opened and closed, and the lubricant L can be discharged or stopped from being discharged.

[0054] In addition, in this embodiment, the lubricant L is ejected from multiple nozzles 80 so as to fill the space between the lower surface of the first ejection portion 61A adjacent to the workpiece W and the upper surface of the workpiece W, and the space between the upper surface of the second ejection portion 61B adjacent to the workpiece W and the lower surface of the workpiece W. Therefore, in this embodiment, the first discharge part 61A and the second discharge part 61B discharge the lubricant L so as to apply it to the upper and lower surfaces of the workpiece W, respectively.

[0055] Incidentally, in the stretch forming apparatus 1 of this embodiment, as described above, the workpiece W is formed by pulling one end of the workpiece W in the X direction by the pulling mechanism 4. Then, the lubricant L is discharged from the first discharge part 61A and the second discharge part 61B onto the upper and lower surfaces of the workpiece W, respectively, while the workpiece W is being pulled and moving in the X direction.

[0056] In this case, for example, if only multiple nozzles 80 are formed in the discharge section 61 as shown in Figure 8(a), there is a possibility that the lubricant L will be applied only to the part of the workpiece W facing the nozzle 80, as shown by the diagonal lines in Figure 8(b). Furthermore, even if the lubricant L can be ejected onto the entire surface of the workpiece W, there is a possibility that the amount of lubricant L ejected will vary from position to position on the workpiece W.

[0057] Therefore, in this embodiment, as shown in FIG. 7, a plurality of grooves 85 extending in the X direction while zigzagging in the Y direction are formed on the lower surface of the first discharge section 61A and the upper surface of the second discharge section 61B, and a nozzle 80 is opened in each groove 85. With this configuration, the lubricant L discharged from the nozzle 80 spreads along the grooves 85 while being applied to the workpiece W. Therefore, it is possible to apply the lubricant L evenly to the entire top and bottom surfaces of the workpiece W.

[0058] 4, in the stretch forming apparatus 1 according to this embodiment, a heating mechanism 9 for heating the lubricant L is provided in the discharge section 61. That is, a heating mechanism 9 is provided in each of the lubricant reservoir 66A of the first discharge section 61A and the lubricant reservoir 66B of the second discharge section 61B. Therefore, by heating the lubricant L with the heating mechanism 9, it is possible to reduce the viscosity of the lubricant L and increase the fluidity of the lubricant L, making it possible to eject a sufficient amount of lubricant L from the nozzle 80.

[0059] In this way, according to the stretch molding device 1 of this embodiment, by heating the lubricant L with the heating mechanism 9, the fluidity of the lubricant L can be increased, making it possible to eject a sufficient amount of lubricant L from the nozzle 80. Therefore, even in winter when the temperature is low and the viscosity of the lubricant L is high, it is possible to discharge a sufficient amount of lubricant oil onto both sides of the workpiece W. Therefore, even if the workpiece W is clamped with high pressure by the clamping mechanism 2, it is possible to prevent the surfaces of the workpiece W from being scratched or galled.

[0060] 9, the conventional stretch forming apparatus 100 does not have a heating mechanism in the discharge section 101. The lubricant L heated by the heating mechanism 103 in the oil tank 102 is sent to the lubricant reservoir 104 in the discharge section 101 to warm the lubricant L in the lubricant reservoir 104. Therefore, in the conventional stretch forming apparatus 100, it takes half a day or a whole day for the viscosity of the lubricant L in the lubricant reservoir 104 to decrease and become fluid enough to be suitable for discharging onto the workpiece W.

[0061] In contrast, in the stretch molding device 1 of this embodiment, by heating the lubricant L using the heating mechanism 9 provided in the discharge section 61 as described above, it is possible to reduce the viscosity of the lubricant L in the discharge section 61 and increase the fluidity of the lubricant L. Therefore, the viscosity of the lubricant L becomes fluid enough to be suitable for dispensing onto the workpiece W in one hour or at most a few hours. Therefore, it is possible to rapidly increase the fluidity of the lubricant L whose fluidity has deteriorated due to low temperature or the like, and then dispense it.

[0062] The specific configuration of the discharge section 61 of the discharge mechanism 6 according to this embodiment will be described below. As described above, the discharge part 61 is provided with the heating mechanism 9 for heating the lubricant L. The heating mechanism 9 can be installed, for example, by being attached to the inside of a wall portion facing the workpiece W, in which the nozzles 80 of the first discharge section 61A and the second discharge section 61B are formed, or by being embedded in the wall.

[0063] Also, as shown in FIG. 6(a), the heating mechanism 9 can be disposed so as to protrude into the lubricant reservoir 66. With this configuration, the lubricant L in the lubricant reservoir 66 can be efficiently heated by the heating mechanism 9 protruding into the lubricant reservoir 66 .

[0064] In this case, the heating mechanism 9 can be configured to include a heater 91, and the heater 91 can be inserted into a metallic protective tube 92 that is arranged so as to protrude into the lubricant reservoir 66. The lubricant reservoir 66 is normally filled with lubricant L, but if air gets into the lubricant reservoir 66 and there is no lubricant L around the heater 91, and there is no protective tube 92 around the heater 91, the heater 91 will essentially be left empty, which could damage the heater 91.

[0065] However, if a protective tube 92 is provided around the heater 91 as in this embodiment, the heater 91 can be prevented from running dry, and damage to the heater 91 can be prevented. Furthermore, since the lubricant reservoir 66 is sealed by the protective tube 92, even if the heater 91 is pulled out from the lubricant reservoir 66, it is possible to prevent the lubricant L in the lubricant reservoir 66 from leaking out.

[0066] On the other hand, in this embodiment, as described above, the discharge section 61 is connected to a circulation mechanism 8 including a discharge path 70 for discharging the lubricant L into the recovery tank 72, so that the lubricant L in the lubricant reservoir 66 of the discharge section 61 can be circulated. Therefore, in this embodiment, the lubricant L is heated by the heating mechanism 9 of the discharge part 61, and the lubricant L heated in the oil tank 62 is circulated and flows into the discharge part 61. Therefore, it is possible to rapidly heat the lubricant L in the discharge part 61, and it is possible to rapidly increase the fluidity of the lubricant L.

[0067] As shown in FIG. 10, the discharge part 61 is provided with an inlet 86A and an outlet 86B for the lubricant L. A supply path 63 for the lubricant L from the oil tank 62 is connected to the inlet 86A, and a discharge path 70 for the lubricant L to the recovery tank 72 is connected to the outlet 86B.

[0068] The lubricant L flows inside the lubricant reservoir 66 from the inlet 86A toward the outlet 86B. In this embodiment, the heating mechanism 9 is provided on both the inlet 86A side and the outlet 86B side of the lubricant reservoir 66, but it is desirable to provide it at least on the inlet 86A side, i.e., the side where the lubricant L flows into the lubricant reservoir 66.

[0069] If the heating mechanism 9 is provided only on the outlet 86B side, i.e., only on the side where the lubricant L is discharged from the lubricant reservoir 66, the lubricant L will be heated by the heating mechanism 9 and immediately discharged, and the lubricant L inside the lubricant reservoir 66 will not be sufficiently heated. In contrast, by providing the heating mechanism 9 at least on the inlet 86A side, i.e., on the inflow side of the lubricant L into the lubricant reservoir 66, the lubricant L heated by the heating mechanism 9 travels a long distance inside the lubricant reservoir 66 before being discharged from the outlet 86B. Therefore, it is possible to heat a large amount of the lubricant L inside the lubricant reservoir 66 as the lubricant L heated by the heating mechanism 9 travels, and it is possible to rapidly heat the lubricant L in the discharge portion 61.

[0070] In this embodiment, the supply mechanism 7 is configured to change the pressure applied to the lubricant L to be supplied in accordance with the temperature T of the lubricant L in the discharge portion 61. In this way, by changing the pressure applied to the lubricant L supplied to the discharge part 61 by the supply mechanism 7, the lubricant L in the discharge part 61 can be rapidly heated.

[0071] In this embodiment, as shown in FIG. 4, a high-pressure relief valve 87, a low-pressure relief valve 88, and an electromagnetic valve 89 are provided between the pump 64 and the control valve 65 in the supply path 63 of the supply mechanism . The pressure of the lubricant L supplied from the supply passage 63 to the discharge portion 61 is switched between high pressure and low pressure by opening and closing the electromagnetic valve 89 .

[0072] An example of how to change the pressure applied to the lubricant L to be supplied will be specifically described below. As shown in Figure 11, when the temperature T of the lubricant L in the lubricant reservoir 66 of the discharge section 61 is at an initial temperature T0, the heating mechanism 75 of the oil tank 62 and the heating mechanism 9 of the discharge section 61 are activated at time t0 to start heating the lubricant L in the oil tank 62 and the lubricant L in the lubricant reservoir 66.

[0073] Then, at time t1 when the temperature T of the lubricant L rises to a temperature T1 at which the pump 64 can start operating, the pump 64 starts operating. At this time, since the control valve 65 and the solenoid valve 89 are both off, i.e., closed, the pump 64 sucks up the lubricant L from the oil tank 62, causing the pressure of the lubricant L in the supply path 63 from the pump 64 to the control valve 65 to increase.

[0074] When the pressure of the lubricant L in the supply path 63 rises to the set pressure of the high-pressure relief valve 87 , the lubricant L in the supply path 63 returns to the oil tank 62 via the relief valve 87 . In this case, the pressure of the lubricant L in the supply passage 63 from the pump 64 to the control valve 65 is the set pressure of the high-pressure relief valve 87 .

[0075] Then, at time t2 when the temperature T of the lubricant L rises to a temperature T2 at which circulation at high pressure, i.e., at the set pressure of the high-pressure relief valve 87, is possible, the control valve 65 and the control valve 71 of the circulation mechanism 8 are turned on. That is, the control valve 65 and the control valve 71 are opened.

[0076] Then, the high-pressure lubricant L heated in the oil tank 62, i.e., the lubricant L at the set pressure of the high-pressure relief valve 87, is forcibly supplied to the lubricant reservoir 66 of the discharge portion 61 through the supply path 63, and begins to flow inside the lubricant reservoir 66. Therefore, the temperature T of the lubricant L in the lubricant reservoir 66 rises rapidly due to the inflow of the lubricant L from the supply path 63 and the heating by the heating mechanism 9.

[0077] Then, at time t3 when the temperature T of the lubricant L rises to a temperature T3 at which circulation at low pressure, i.e., circulation at the set pressure of the low-pressure relief valve 88, becomes possible and the fluidity increases, the solenoid valve 89 is turned on. In other words, the solenoid valve 89 is opened. Then, even if the pressure of the lubricant L in the supply path 63 is reduced to the set pressure of the low-pressure relief valve 88, the lubricant L will be supplied to the lubricant reservoir 66 through the supply path 63, and the temperature T of the lubricant L in the lubricant reservoir 66 will continue to rise due to the inflow of the lubricant L from the supply path 63 and heating by the heating mechanism 9.

[0078] In this way, even when the temperature T of the lubricant L is low and the viscosity of the lubricant L is high, the temperature T of the lubricant L in the discharge portion 61 can be increased more rapidly by sending the lubricant L into the discharge portion 61 at high pressure. That is, compared to when the lubricant L is supplied at a low pressure without changing the pressure, it is possible to at least shorten the time it takes for the temperature T of the lubricant L to rise from T2 to T3 in FIG.

[0079] Therefore, the time from time t0 when the temperature T of the lubricant L in the lubricant reservoir 66 of the discharge section 61 is at the initial temperature T0 to time t4 when the temperature T reaches the temperature T4 at which the lubricant L can be discharged from the nozzle 80 becomes shorter. Therefore, as described above, by configuring the supply mechanism 7 to change the pressure applied to the lubricant L depending on the temperature T of the lubricant L in the discharge portion 61, it is possible to rapidly warm the lubricant L in the discharge portion 61.

[0080] In addition, if the initial temperature T0 of the lubricant L in the lubricant reservoir 66 of the discharge section 61 is equal to or higher than the temperature T1 at which the pump 64 can start operating, the pump 64 may start operating from the beginning, i.e., immediately at time t0. Furthermore, if the initial temperature T0 of the lubricant L is equal to or higher than the temperature T2 at which circulation is possible at the set pressure of the high-pressure relief valve 87, the pump 64 may be started to operate from the beginning, i.e., immediately at time t0, and the control valves 65 and 71 may be opened to start supplying the high-pressure lubricant L to the discharge section 61.

[0081] Furthermore, if the initial temperature T0 of the lubricant L is equal to or higher than the temperature T3 at which circulation at the set pressure of the low-pressure relief valve 88 is possible, the pump 64 may be started to operate from the beginning, i.e., immediately at time t0, and the control valves 65, 71, and solenoid valve 89 may be opened to start supplying the low-pressure lubricant L to the discharge section 61. Furthermore, if the initial temperature T0 of the lubricant L is equal to or higher than the temperature T4 at which the lubricant L can be discharged from the nozzle 80, the pump 64 may be started to operate from the beginning, i.e., immediately at time t0, the control valve 65 and the solenoid valve 89 may be opened, the control valve 71 may be closed, and the discharge of the lubricant L from the nozzle 80 may be started while supplying low-pressure lubricant L to the discharge section 61.

[0082] As described above, before the forming of the workpiece W is started, the lubricant L must be heated to increase the fluidity of the lubricant L so that the lubricant L can be discharged. Therefore, in this embodiment, as described above, before the lubricant L is discharged onto the workpiece W, the control valves 71 provided in the discharge paths 70 of the circulation mechanism 8 shown in Figure 4 are opened to circulate the lubricant L and warm the lubricant L in the lubricant reservoir 66.

[0083] However, if the control valves 71 remain open after the molding of the workpiece W has begun and the discharge of the lubricant L from the nozzle 80 of the discharge section 61 has begun, the lubricant L may be discharged from the outlet 86B, and the pressure in the lubricant reservoir 66 may not increase sufficiently. If the pressure in the lubricant reservoir 66 does not increase, the nozzle 80 may not be able to discharge an appropriate amount of lubricant L.

[0084] Therefore, in this embodiment, when the forming of the workpiece W begins and the lubricant L is ejected from the nozzle 80, each control valve 71 of the circulation mechanism 8 is closed to stop the circulation of the lubricant L by the circulation mechanism 8. With this configuration, it is possible to increase the pressure inside the lubricant reservoir 66, and it is possible to discharge an appropriate amount of lubricant L from the nozzle 80.

[0085] It goes without saying that the present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0086] 1 Stretch forming device 2. Clamping mechanism 3 Molding section 4 Pulling mechanism 7 Supply mechanism 8 Circulation mechanism 9 Heating mechanism 61 Discharge part 66 Lubricant reservoir 86A Inlet (lubricant inlet side) 91 Heater 92 Protective tube L Lubricant T lubricant temperature double work

Claims

1. a clamping mechanism that clamps a portion of a plate-shaped workpiece; a pulling mechanism that pulls another portion of the workpiece while the workpiece is clamped by the clamping mechanism; a forming unit that forms the workpiece between the clamping mechanism and the pulling mechanism; Discharge units disposed on both sides of the workpiece on the opposite side of the clamping mechanism from the pulling mechanism, and configured to discharge lubricant onto each surface of the workpiece; a heating mechanism provided in the discharge section and configured to heat the lubricant; Stretch forming equipment.

2. The discharge unit discharges the lubricant so as to apply it to each surface of the workpiece. The stretch forming apparatus of claim 1.

3. the discharge portion has a lubricant reservoir that stores the lubricant, and the heating mechanism is provided in the lubricant reservoir. The stretch forming apparatus of claim 1.

4. The heating mechanism is arranged to protrude into the lubricant reservoir.

4. The stretch forming apparatus of claim 3.

5. the heating mechanism includes a heater; the heater is inserted into a protective tube arranged to protrude into the lubricant reservoir.

4. The stretch forming apparatus of claim 3.

6. the heating mechanism is provided at least on an inflow side of the lubricant into the lubricant reservoir; 4. The stretch forming apparatus of claim 3.

7. A circulation mechanism for circulating the lubricant is provided. The stretch forming apparatus of claim 1.

8. The circulation mechanism circulates the lubricant before discharging it onto the workpiece.

8. The stretch forming apparatus of claim 7.

9. When the lubricant is discharged, the circulation mechanism stops circulating the lubricant.

9. The stretch forming apparatus of claim 8.

10. a supply mechanism for supplying the lubricant to the discharge portion, the supply mechanism changes the pressure applied to the lubricant in accordance with the temperature of the lubricant at the discharge portion. The stretch forming apparatus of claim 1.

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