JP2013121613A - Pressing device and pressing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable at least blanking work and bending work by one pressing stage while evading complication of the device configuration and the contents of control.SOLUTION: A rocking cylinder 40 is used as a means for generating necessary stroke motion to the blanking/bending blade 20 of a lower die 14. In the state that energizing force from the piston rod 40a of the rocking cylinder 40 acts on the blanking/bending blade 20, by receiving the stroke motion of the bending blade 16 of an upper die 12, the blanking/bending blade 20 gives the stroke motion acting in concert therewith to the blanking/bending blade 20 of a lower die 14. The piston rod of the rocking cylinder 40 is held in the position corresponding to the bottom dead center of the stroke motion of the blanking/bending blade 20 within the range of a predetermined press angle after reaching the bottom dead center. Accordingly, it can be evaded that the deformation of a panel product W' occurs due to forcible raising of a panel product W' (so-called "lifted" state) by the elevation of a lower blanking blade 20.

Description

  The present invention relates to a pressing apparatus and a pressing method.

  In producing panel products by press forming plate-like workpieces, it is necessary to perform a plurality of types of processing such as punching, bending, squeezing, and punching according to the required product shape. In such a case, conventionally, it has been common to prepare a press die for each process and perform each process in order. However, in response to a request for reducing the production cost of a mold, a so-called composite press apparatus having a mold capable of performing many kinds of processing only in one press process has been developed (for example, Patent Document 1). , See Patent Document 2).

  In addition, the present inventors provide a cutting blade and a curved blade on the upper die, and the upper blade and the curved blade are respectively placed at a predetermined press angle with respect to the plate-like workpiece set on the lower die. We have developed a mold structure that can perform punching and bending in a single press process by pressing (see, for example, Non-Patent Document 1). Note that the term “press angle” in the present description is displayed by applying an operation related to a single press process within a range of 0 ° to 360 ° for the sake of convenience in order to clarify the progress of press processing by the press machine. Is. For example, the press angle when the upper die that is raised and lowered is at the top dead center is 0 ° or 360 °, and the press angle when it is at the bottom dead center is 180 °.

JP 09-192751 A JP 2005-329413 A

Toyota Motor Corporation, “Toyota Technical Disclosure Collection”, issue number 23143, issue date July 30, 2010

In the non-patent document 1, a gas using nitrogen gas as a working fluid as a means for generating a necessary stroke operation for each of the extracted blade and the curved blade after the press contact, and the timing of the press contact of the extracted blade and the curved blade. A cylinder (hereinafter referred to as “N2 gas cylinder”) is used. In addition, it is possible to appropriately generate the necessary pressure contact load and the operation stroke. This N2 gas cylinder functions as a so-called gas spring by the expansion and contraction of the piston rod according to the applied load, and can sufficiently cope with a large load required for application to a press machine. Is. And by the expansion and contraction operation of the N2 gas cylinder, it is possible to perform the punching and bending required for the plate-like workpiece in a single pressing step without performing complicated load control.

By the way, depending on the required product shape, it may be necessary to receive a stroke operation of the upper mold bending blade and cause the lower mold bending blade to perform a corresponding stroke operation. At this time, if the N2 gas cylinder is used as a means for generating the stroke operation necessary for the bending blade as in the above example, the upper die passes the bottom dead center and rises again, so that the bending blade becomes When the applied load is reduced, the N2 gas cylinder that has been shrunk under the load is extended, and the bending blade is also raised.

Usually, at this point, since the panel product is held by the pad constituting the press mold, the panel product is forcibly lifted by the raising of the lower punching blade (so-called “or up” state). The panel product will be transformed. Such a problem can be avoided by using an actuator capable of controlling any expansion / contraction operation such as a hydraulic cylinder as a means for generating a stroke operation necessary for the lower bending blade. This complicates the structure of the metal mold.

The present invention has been made in view of the above problems, and the object of the present invention is to perform at least a punching process and a bending process in a single pressing process while avoiding the complexity of the apparatus configuration and control contents. The present invention is to provide a press apparatus and a press method.

In order to solve the above problems, a pressing apparatus and a pressing method according to the present invention include a pair of dies including a cutting blade, a bending blade, and a bending blade, and each blade performs a punching process and a bending process at a predetermined pressing angle. By performing processing, a plate-shaped workpiece is formed into a predetermined panel product in a single pressing process, and when the mold is opened, some blades operate during a predetermined press angle range. By limiting the above, it is possible to prevent an excessive force from being applied to the panel product.
(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the constituent elements of each section are replaced, deleted, or still other configurations in consideration of the mode for carrying out the invention. What added the element can also be included in the technical scope of this invention.

(1) including a first mold that includes at least a cutting blade and a curved blade, and a second mold that includes at least a bending blade that faces the curved blade of the first mold in the stroke direction,
The punching blade of the first die and the curved blade are brought into pressure contact with each other at a predetermined press angle to the plate-shaped workpiece set in the second die, and together with the bending blade of the lower die, A pressing device that performs at least a punching process and a bending process in one press process,
A gas cylinder that receives a stroke operation of the curved blade of the first type and applies a corresponding stroke operation to the bent blade of the second type, and a piston rod of the gas cylinder between a predetermined press angle range. And a holding means for holding at a position corresponding to the end position of the stroke operation of the bending blade. (Claim 1).

The press device described in this section is configured to press the first type extraction blade and the curved blade at a predetermined press angle against the plate-like workpiece set in the second type, respectively, and thereby extract the second type. Together with the blade, it constitutes a so-called composite press apparatus that performs at least a punching process and a bending process in a single pressing step. Further, a gas cylinder is used as a means for generating a stroke operation necessary for the second type bending blade, and the bending blade is in a state in which the urging force from the piston rod of the gas cylinder is applied to the bending blade. By receiving the stroke motion of the first type curved blade, the corresponding stroke motion is given to the second type curved blade.
And by holding the piston rod of the gas cylinder at a position corresponding to the end position of the stroke operation of the bending blade during a predetermined press angle range by the holding means, the upper die passes the bottom dead center, Even if the load applied to the bending blade decreases by turning up again, the gas cylinder that has received the load until then and has contracted the piston rod will not expand, and the bending blade will rise accordingly. Is to avoid.

(2) In the above item (1), the holding means includes a gas supply / exhaust circuit communicating with the gas cylinder (claim 2).
The press device described in this section includes a gas supply / exhaust circuit communicating with the gas cylinder as a holding means for holding the piston rod of the gas cylinder at a position corresponding to the end position of the stroke operation of the bending blade. . Then, the piston rod is held for a predetermined press angle range by extracting / removing the gas in the gas cylinder via the gas supply / exhaust circuit.

(3) In the above item (2), the gas supply / exhaust circuit includes, in the cylinder chamber of the gas cylinder, the end position of the stroke operation of the piston rod between the end surface defining the end position and the piston rod. A press apparatus comprising external storage means for temporarily discharging and storing the gas remaining in the gas cylinder to the outside of the gas cylinder, and for appropriately returning the gas to the gas cylinder (Claim 3).
In the press device described in this section, the external storage means provided in the gas supply / exhaust circuit is provided between the end surface of the cylinder chamber of the gas cylinder and the piston rod between the end surface that determines the end position at the end position of the stroke operation of the piston rod. The gas remaining in is temporarily discharged out of the gas cylinder and stored. And, by letting the gas remaining between the end face that defines the end point position and the piston rod completely exhaust from the cylinder chamber, the first mold passes the bottom dead center and then rises again, giving it to the bending blade Even if the applied load is reduced, the gas cylinder avoids the occurrence of springback due to the residual gas. And the piston rod of a gas cylinder is hold | maintained in the position corresponding to the end point position of the stroke operation | movement of a bending blade between predetermined press angle ranges. Further, the gas discharged from the cylinder chamber is stored, and when the predetermined press angle range is passed, the gas is returned to the gas cylinder to release the piston rod holding state. Further, the gas discharged from the cylinder chamber is recirculated to prevent a reduction in gas necessary for the operation of the gas cylinder.

(4) In the above item (3), the external storage means sucks the gas remaining between the end face of the cylinder chamber of the gas cylinder that defines the end position of the stroke operation of the piston rod and the piston rod. A storage cylinder that generates a negative pressure
A discharge pipe and a reflux pipe communicating with a cylinder chamber formed between the end face of the cylinder chamber of the gas cylinder and defining an end point of stroke operation of the piston rod and the piston rod;
A press device including a valve that brings the discharge pipe into a communicating state until the curved blade of the first type reaches at least the end point position of the stroke operation in the discharge pipe (Claim 4).

The press device described in this section is configured such that a discharge pipe is provided between a cylinder chamber formed between an end face of a cylinder chamber of a gas cylinder and a piston rod stroke end position for determining a stroke end point position of the piston rod, and a storage cylinder. The gas is circulated between the cylinder chamber and the storage cylinder by communicating with the passage and the reflux pipe. Then, by generating a negative pressure capable of sucking the remaining gas between the end surface of the cylinder chamber of the gas cylinder and the end face position of the stroke operation of the piston rod and the piston rod by the storage cylinder of the external storage means. The gas remaining between the end face defining the end point position and the piston rod is completely discharged from the cylinder chamber via the discharge pipe.
In addition, the valve provided in the discharge pipe causes the discharge pipe to communicate with the storage cylinder from the cylinder chamber of the gas cylinder until the curved blade of the first type reaches at least the end point position of the stroke operation. Gas distribution to In addition, when the predetermined press angle range is passed, the exhaust pipe is closed by a valve so that the gas is recirculated from the storage cylinder to the gas cylinder through the recirculation pipe. The holding state in which the rod is held at a position corresponding to the end position of the stroke operation of the bending blade is released.

(5) The gas cylinder includes a gas exchange circuit that exchanges gas between cylinder chambers separated in a stroke direction of the piston rod in accordance with the operation of the piston rod, and the gas exchange circuit includes the piston rod A press apparatus including an operation control valve for preventing gas exchange between cylinder chambers separated in a stroke direction, wherein the return conduit of the external storage means is connected to the operation control valve.
The press device described in this section enables the stroke operation of the piston rod by performing gas exchange between the cylinder chambers separated in the stroke direction of the piston rod by the gas exchange circuit of the gas cylinder. Moreover, the gas exchange circuit includes an operation control valve for preventing gas exchange between the cylinder chambers separated in the stroke direction of the piston rod, and the return conduit of the external storage means is connected to the operation control valve. . Then, by appropriately switching the operation control valve, the holding state of holding the piston rod of the gas cylinder at a position corresponding to the end position of the stroke operation of the bending blade is maintained or released.

(6) In the above items (4) and (5), a mechanical valve that switches according to the operation of the first type is provided, the valve of the external storage means provided in the discharge pipe, and the gas cylinder One or both of the operation control valves receives the air supplied via the mechanical valve and performs a predetermined switching operation (Claim 6).
In the press device described in this section, one or both of the valve provided in the discharge pipe of the external storage means and the operation control valve of the gas cylinder receives air supplied via the mechanical valve, A predetermined switching operation is performed. That is, one or both of the valve provided in the discharge pipe and the operation control valve of the gas cylinder perform a predetermined switching operation according to the first type operation.

(7) Using a first mold having at least a cutting blade and a curved blade, and a second mold having at least a bending blade facing the curved blade of the first mold in the stroke direction,
The punching blade of the first die and the curved blade are brought into pressure contact with each other at a predetermined press angle to the plate-shaped workpiece set in the second die, and together with the bending blade of the lower die, A pressing method in which at least a punching process and a bending process are performed in one press process,
A stroke operation corresponding to the stroke operation of the curved blade of the first type is applied to the bending blade of the second type using a gas cylinder, and the piston rod of the gas cylinder is placed within a predetermined press angle range. A pressing method in which the bending blade is restroked after being held at a position corresponding to the end position of the stroke operation of the bending blade (Claim 7).

In the pressing method described in this section, the first die extraction blade and the curved blade are brought into pressure contact with the plate-shaped workpiece set in the second die at a predetermined press angle, respectively, and the lower die is bent. Together with the blade, a so-called composite press method is performed in which at least a punching process and a bending process are performed in a single pressing process. In addition, a gas cylinder is used as a means for generating a stroke operation necessary for the second type bending blade, and the bending blade is in a state where the biasing force from the piston rod of the gas cylinder acts on the bending blade. By receiving the stroke motion of the curved blade, a stroke motion corresponding to the stroke motion is given to the second type curved blade.
Furthermore, by holding the piston rod of the gas cylinder at a position corresponding to the end position of the stroke operation of the bending blade for a predetermined press angle range, the upper die passes the bottom dead center and starts to rise again. Even if the load applied to the bending blade decreases, the gas cylinder that has received the load until then and has contracted the piston rod will not expand, thereby preventing the bending blade from rising. is there. Then, after holding at the position corresponding to the end position of the stroke operation of the bending blade for a predetermined press angle range, the pressing blade is restroked to complete one press process, The first and second molds return to the mold open state.

  (8) In the above paragraph (7), the gas remaining between the end face defining the end position and the piston rod at the end position of the operating stroke of the piston rod in the cylinder chamber of the gas cylinder is the gas By temporarily discharging and storing outside the cylinder, the piston rod of the gas cylinder is held at a position corresponding to the end position of the stroke operation of the bending blade during a predetermined press angle range, and the gas A press method in which the bending blade is restroked by appropriately returning the gas temporarily stored outside the cylinder to the gas cylinder (Claim 8).

  In the pressing method described in this section, in the cylinder chamber of the gas cylinder, at the end point position of the stroke operation of the piston rod, the gas remaining between the end surface defining the end point position and the piston rod is temporarily moved out of the gas cylinder. Discharged and stored. And, by letting the gas remaining between the end face that defines the end point position and the piston rod completely exhaust from the cylinder chamber, the first mold passes the bottom dead center and then rises again, giving it to the bending blade Even if the applied load is reduced, the gas cylinder avoids the occurrence of springback due to the residual gas. And the piston rod of a gas cylinder is hold | maintained in the position corresponding to the end point position of the stroke operation | movement of a bending blade between predetermined press angle ranges. In addition, the gas discharged into the gas cylinder chamber is stored, and when the predetermined press angle range is passed, the gas is returned to the gas cylinder, thereby releasing the piston rod holding state. Further, the gas exhausted from the cylinder chamber and temporarily stored gas is refluxed to prevent a reduction in gas necessary for the operation of the gas cylinder.

  Since the present invention is configured as described above, a pressing apparatus and a pressing method capable of performing at least a punching process and a bending process in a single pressing process while avoiding the complexity of the apparatus configuration and control contents are provided. Will be.

It is sectional drawing which shows typically the main structure of the lower mold | type of the press apparatus which concerns on embodiment of this invention. FIG. 2 is a lower-type operation control system piping diagram shown in FIG. 1. (A) to (c) shows the internal structure of the gas cylinder used in the press device according to the embodiment of the present invention, and the mode of switching of the operation control valve in the stroke operation of the gas cylinder, (D) is explanatory drawing which shows generation | occurrence | production of the spring back in a gas cylinder with the stroke operation | movement of the upper mold | type and lower mold | type gas cylinder corresponding to a press angle. (A) is a schematic diagram showing an operation control system pipe having a gas cylinder according to an embodiment of the present invention, a storage cylinder, and a discharge pipe and a reflux pipe communicating both; (B) is explanatory drawing which shows that generation | occurrence | production of the spring back in a gas cylinder is suppressed by the operation control system piping of (a) with the stroke operation | movement of the upper mold | type and lower mold | type gas cylinder corresponding to a press angle. . It is the flowchart figure which showed operation | movement of each part in one press process of the press apparatus which concerns on embodiment of this invention in light of the press angle. The operation of each valve provided in the operation control system piping of the press device according to the embodiment of the present invention will be described, and (a) shows the relationship between the press angle and each step in FIG. (B) shows the stroke operation of the upper and lower gas cylinders corresponding to the press angle of (a) in the upper stage, the control air pressure applied to the operation control valve of the gas cylinder in the middle stage, The control air pressures applied to the valves provided in the discharge pipeline are respectively shown. It is sectional drawing which shows operation | movement of the press apparatus which concerns on embodiment of this invention, (a) shows the state which mounted the plate-shaped workpiece in the lower mold | type, and hold | maintained the plate-shaped workpiece | work with the pad of the upper mold | type, (B) shows the state which carried out the punching process to the plate-shaped workpiece | work with the upper die cutting blade and the lower die bending blade. Continuing to FIG. 7, (a) shows a state in which the plate-shaped workpiece is bent by the upper mold bending blade and the lower mold bending blade, and (b) shows the upper mold punching pin. The state which carried out the hole punching process to the plate-shaped workpiece is shown. Continuing to FIG. 8, (a) shows the state where the upper die cutting blade, the curved blade, and the lower die cutting blade have reached the bottom dead center of the stroke operation, and (b) shows the lower die bending. The state in which the upper die cutting blade, the curved blade, and the pad have started to rise from the bottom dead center in a state where the blade is held at the bottom dead center of the stroke operation. FIG. 10 shows the upper and lower molds in an open state following FIG. 9. In the lower mold operation control system piping diagram shown in FIG. 2, the state of each valve when the press angle is 0 ° to 180 ° is shown. In the lower mold operation control system piping diagram shown in FIG. 2, the state of each valve when the press angle is 180 ° to 220 ° is shown. In the lower mold operation control system piping diagram shown in FIG. 2, the state of each valve when the press angle is 220 ° to 360 ° is shown.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. Note that the same or corresponding parts as those of the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
First, a schematic configuration of a press apparatus according to an embodiment of the present invention will be described with reference to FIG. The press apparatus 10 according to the embodiment of the present invention has an upper mold 12 as a first mold and a lower mold 14 as a second mold facing the first mold. The upper mold 12 includes at least a cutting blade 16 and a curved blade 18, and the lower mold 14 includes at least a bending blade 20 that faces the curved blade 18 of the upper mold 12 in the stroke direction. .

Here, the upper mold 12 will be described in detail. The extraction blade 16 of the upper mold 12 is fixed to an upper mold base plate 22 that is driven up and down by driving means such as a ram (not shown). Further, the outer shape has a shape that follows the opening shape of the hole to be formed in the plate-like workpiece W. On the other hand, the curved blade 18 is fixed to a movable plate 26 held by a first gas cylinder 24 fixed to the upper mold base plate 22. In the present embodiment, the curved blade 18 has a frame shape surrounding the outer shape of the extraction blade 16. ing.
Further, a second gas cylinder 28 that is in pressure contact with the spacer 34a of the pad 34 is fixed to the movable plate 26 for a predetermined pressing angle. Further, in the illustrated example, a punching pin 30 is fixed to the upper mold base plate 22 so as to penetrate the movable plate 26 and the curved blade 18. In addition, a third gas cylinder 32 is fixed to the upper mold 22, and a pad 34 is held by the third gas cylinder 32. In the present embodiment, an N 2 gas cylinder is used for each of the first to third gas cylinders 24, 28, and 32. Further, the load generated by each gas cylinder is set such that the first gas cylinder 24 is the largest and the third gas cylinder 32 is the smallest so that a predetermined operation procedure described later is realized.

Next, the lower mold 14 will be described in detail. The lower die 14 is provided with a punch 36 at a position that avoids the punching blade 16, the curved blade 18, and the hole punching pin 30 of the upper die 12, and faces at least the pad 34, and this punch 36 has a lower die base plate 38. It is fixed to. In the illustrated example, the punch 36 is formed in a frame shape surrounding the outer shape of the bending blade 20. A locking cylinder 40 is fixed to the lower base plate 38, and a movable plate 42 is fixed to a piston rod 40a of the locking cylinder 40 via a distance block 41 as shown in FIG. The bending blade 20 is fixed to the movable plate 42.
In the present embodiment, an N 2 gas cylinder is also used for the locking cylinder 40. In some cases, a structure in which the movable plate 42 and the bending blade 20 are integrated as an inlet lower steel material may be employed. Further, the lower mold base plate 38 is provided with a body plate 43 (shown only in FIG. 1) for determining a lower limit position (bottom dead center) of the stroke operation of the bending blade 20.

In the present embodiment, the bending blade 20 has a frame shape. Then, in the punching process to be described later (see FIG. 7B), the punched hole 16 of the upper mold 12 and the punched hole having the opening shape necessary for the plate-like workpiece W are formed. Further, in the bending process described later (see FIG. 8A), the bending process is performed along the hole 18 formed in the plate-like workpiece W together with the bending blade 18 of the upper mold 12. Furthermore, in the hole punching process to be described later (see FIG. 8B), a recess for receiving the hole punching pin 30 for punching the plate-like workpiece W together with the hole punching pin 30 of the upper die 12 is provided. It is formed on the bending blade 20.

Here, the specific configuration of the operation control system of the locking cylinder 40 of the lower mold 14 will be described in more detail with reference to FIGS.
The locking cylinder 40 receives a stroke operation of the curved blade 18 of the upper mold 12 and generates a load for applying a stroke operation corresponding to the stroke operation to the extracted blade 20. The operation control system of the locking cylinder 40 corresponds to the stroke end point position (bottom dead center) of the bending blade 20 during the predetermined press angle range of the piston rod 40a of the locking cylinder 40, as will be described later. Holding means for holding at the position to be held. In the present embodiment, this holding means is constituted by a gas supply / exhaust circuit 44 (FIGS. 1 and 2) that communicates with the locking cylinder 40.

FIG. 2 shows a specific configuration example of the gas supply / exhaust circuit 44. In this example, in the cylinder chamber 40b of the locking cylinder 40 (see FIGS. 3 and 4), an end face 40c that defines the bottom dead center (FIGS. 3C and 4A) of the stroke operation of the piston rod 40a; , An external storage means 46 for temporarily discharging and storing the gas remaining between the piston rod 40 a and the outside to the locking cylinder 40 is provided.
As shown in FIGS. 1 and 4A, the external storage means 46 is for sucking the gas remaining between the end surface 40c of the cylinder chamber 40b of the locking cylinder 40 and the piston rod 40a. A storage cylinder (passive cylinder) 48 is included.

In the passive cylinder 48, gas is sealed in a lower cylinder chamber 48b2 (see FIG. 4A) separated by a piston block 48c of the piston rod 48a. Due to the pressure of the sealed gas, the piston rod 48a Usually, it is biased to the most protruding position. When the piston rod 48a is pushed down in conjunction with the downward movement of the upper die 12, for example, in conjunction with the stroke operation of the curved blade 18, a cylinder chamber 48b1 is formed above the piston block 48c of the piston rod 48a. At this time, the cylinder chamber 48b1 has a negative pressure. The gas remaining between the end surface 40c of the cylinder chamber 40b of the locking cylinder 40 and the piston rod 40a is sucked by the negative pressure of the cylinder chamber 48b1.

Further, the external storage means 46 has a cylinder chamber 40b1 formed between the cylinder chamber 48b1 above the passive cylinder 48, the end surface 40c of the cylinder chamber 40b of the locking cylinder 40, and the piston rod 40a (FIG. 3B). A discharge line 50 and a reflux line 52 for communicating with the reference line).
Further, the discharge pipe 50 and the reflux pipe 52 are connected to the passive cylinder 48 via the valve block 56. The valve block 56 is configured so that the bent blade 18 of the upper mold 12 extends from the top dead center to at least the end point position (bottom dead center) of the stroke operation, that is, the piston rod 40a of the locking cylinder 40 performs the stroke operation. A valve 54 is provided for bringing the discharge conduit 50 into a communicating state until the bottom dead center is reached (see FIG. 4A). In the illustrated example, in the valve block 56, the reflux line 52 bypasses the valve 54 and is integrated with the discharge line 50, forming a single flow line 51, and a cylinder chamber 48 b 1 above the passive cylinder 48. It is connected to the.

Furthermore, the locking cylinder 40 includes a gas exchange circuit that exchanges gas between cylinder chambers 40b1 and 40b2 (see FIG. 3B) separated in the stroke direction of the piston rod 40a in accordance with the operation of the piston rod 40a. Yes.
The configuration of the gas exchange circuit of the locking cylinder 40 in the present embodiment will be described with reference to FIG. First, the piston rod 40a includes a check valve 58 in its piston block 40d. The check valve 58 is opened when the piston rod 40a descends the cylinder chamber 40b (the locking cylinder 40 is shortened), and the gas in the cylinder chamber 40b1 below the piston block 40d causes the check valve 58 to be released. By moving to the upper cylinder chamber 40b2, the downward stroke operation of the piston rod 40a is permitted.

Also, a bottomed cylindrical rod 40e of the piston rod 40a is inserted into a cylindrical inner rod 40f that penetrates the end surface 40c of the cylinder chamber 40b1. Further, the inner rod 40f is connected to an operation control valve 60 in the cartridge valve 62 provided with an end face 40c of the cylinder chamber 40b. By switching the operation control valve 60, the inner rod 40f is selectively connected to the cylinder chamber 40b1 facing the end surface 40c among the cylinder chambers 40b1 and 40b2 separated in the stroke direction of the piston rod 40a. It is like that.

Further, the cylindrical inner rod 40f communicates with the upper cylinder chamber 40b2 through a bottomed cylindrical rod 40e of the piston rod 40a. For this reason, when the cylinder chamber 40b1 and the inner rod 40f are connected by the operation control valve 60, the two cylinder chambers 40b1 and 40b2 separated by the piston block 40d are in a communication state. This state is a mode when the piston rod 40a moves up the cylinder chamber 40b (the locking cylinder 40 extends), the check valve 58 of the piston block 40d is closed, and the upper cylinder chamber 40b2 is closed. The gas moves through the rod 40e, the inner rod 40f, and the operation control valve 60 to the lower cylinder chamber 40b1.
As shown in FIG. 4 (a), the reflux conduit 52 of the storage means 46 is connected to the operation control valve 60, and the gas temporarily stored in the cylinder chamber 48 b 1 above the passive cylinder 48. Is recirculated to the cylinder chamber 40 b 1 below the locking cylinder 40 via the flow line 51, the reflux line 52, and the operation control valve 60.

On the other hand, when the operation control valve 60 is in a state of blocking the cylinder chamber 40b1 and the inner rod 40f, communication between the two cylinder chambers 40b1 and 40b2 via the rod 40e and the inner rod 40f is prevented, and Since the check valve 58 of the piston block 40d is closed, the piston rod 40a is held at the bottom dead center of the stroke operation without ascending the cylinder chamber 40b. In addition, the gas temporarily stored in the cylinder chamber 48b1 above the passive cylinder 48 is blocked by the operation control valve 60, and is prevented from returning to the cylinder chamber 40b1 below the locking cylinder 40.
The valve 54 of the valve block 56 and the operation control valve 60 of the cartridge valve 62 can have the same structure. In the illustrated example, both are supplied with air (high-pressure air having a pressure of at least 4 bar in the illustrated example) as an operating fluid, and perform a predetermined switching operation.

In addition, air is supplied to the valve 54 and the operation control valve 60 through a mechanical valve 64 (see FIG. 2) that switches according to the operation of the upper mold 12, for example, appropriate air supply such as existing high-pressure air piping. From the source. The mechanical valve 64 is fixed to the lower mold base plate 38, for example, similarly to the passive cylinder 48 shown in FIG. 1, and the switching operation is performed upon the lowering of the curved blade 18 of the upper mold 12.
In addition, in the gas supply / exhaust circuit 44 shown in FIG. 2, reference numeral 66 denotes a check valve provided downstream of the mechanical valve 64, and reference numerals 68 and 70 denote first and second control operations related to the press apparatus described later. 2-operating valve, 72 is an N2 gas pressure gauge, 74 is a bottom dead center lock display board for indicating the state of stroke operation of the locking cylinder 40, and 76 is an N 2 communicating with the pressure monitor of the locking cylinder 40 It is piping.

  Subsequently, the locking cylinder 40 receives the stroke operation of the curved blade 18 of the upper mold 12 and applies a corresponding stroke operation to the extracted blade 20 of the lower mold 14, and the piston rod 40 a of the locking cylinder 40 is moved to a predetermined position. A specific operation of the gas supply / exhaust circuit 44 that enables the bending blade 20 to be held at a position corresponding to the bottom dead center during the press angle range will be described below.

  First, the expansion and contraction operation of the piston rod 40a in the rocking cylinder 40 alone without the gas supply / exhaust circuit 44 will be described with reference to FIG. When the piston rod 40a is at the top dead center of the stroke operation shown in FIG. 3A, a downward load is applied to the piston rod 40a with the operation control valve 60 of the cartridge valve 62 closed. At this time, as shown in FIG. 3B, the gas in the lower cylinder chamber 40b1 moves to the upper cylinder chamber 40b2 via the check valve 58 of the piston block 40e, and the piston rod 40a moves to the cylinder chamber. 40b is moved downward. As shown in FIG. 3 (c), the piston block 40d of the piston rod 40a is the bottom dead center of the stroke operation of the piston rod 40a in a state where the piston block 40d is in contact with the end surface 40c of the cylinder chamber 40b.

  The operation of the locking cylinder 40 so far is compared with the relational diagram of the stroke operation of the upper mold 12 and the locking cylinder 40 with respect to time (time) shown in FIG. First, when the upper die 12 starts to descend from the state of the top dead center of the locking cylinder 40 shown in FIG. 3A, a curve indicating that (a thin line indicated by “press”) is received and at a certain point in time. To the curve indicating the expansion / contraction operation of the locking cylinder 40 (thick line indicated by the symbol “spring”) is also changed in the shortening direction, and then the bottom dead center (FIG. 3B) in a state where the two curves match. It leads to.

Now, when the load applied to the bending blade 20 is reduced by the upper die 12 passing the bottom dead center and starting to rise again, the downward load on the piston rod 40a of the locking cylinder 40 is removed. At this time, even if the operation control valve 60 of the cartridge valve 62 is kept closed, the cartridge valve 62 remains between the end surface 40c of the cylinder chamber 40b that defines the bottom dead center of the piston rod 40a and the piston block 40d of the piston rod 40a. The gas that expands expands as the load is removed. As a result, as shown in an enlarged view in FIG. 3D, a springback (MAX 1 mm in the illustrated example) is generated in the locking cylinder 40.

Thereafter, when the operation control valve 60 of the cartridge valve 62 is opened, the gas in the upper cylinder chamber 40b2 is in a state where the check valve 58 of the piston block 40d is closed and the rod 40e, the inner rod 40f, the operation control valve. It moves to the lower cylinder chamber 40b1 via 60. Therefore, when the operation control valve 60 is opened, the piston rod 40a performs a restroke operation, and as shown in FIG. Changes to. Then, the piston rod 40a returns to the top dead center.

On the other hand, the expansion / contraction operation | movement of the piston rod 40a at the time of combining the gas supply / exhaust circuit 44 with the rocking cylinder 40 based on embodiment of this invention is demonstrated, referring FIG.
Also in this case, the operation from the piston rod 40a stroke operation at the top dead center to the bottom dead center does not include the gas supply / exhaust circuit 44 shown in FIGS. 3 (a) to 3 (c). It is the same. Therefore, even if the operation of the locking cylinder 40 so far is shown in FIG. 4B in view of the relationship between the stroke of the upper mold 12 and the locking cylinder 40 with respect to time (stroke), FIG. It becomes the same as 3 (d).

  However, in the present embodiment, until the piston rod 40a reaches the bottom dead center, the valve 54 of the valve block 56 is connected to the discharge pipe 50 as shown in FIG. Switch to. Then, the gas between the end surface 40c of the cylinder chamber 40b that defines the bottom dead center of the piston rod 40a and the piston block 40d of the piston rod 40a is sucked into the cylinder chamber 48b1 above the passive cylinder 48 and stored. It will be. Therefore, the residual gas between the end surface 40c of the cylinder chamber 40b and the piston block 40d of the piston rod 40a is completely removed.

When the load applied to the bending blade 20 is reduced by the upper die 12 passing the bottom dead center and rising again, the downward load on the piston rod 40a of the locking cylinder 40 is removed. At this time, since there is no residual gas between the end face 40c of the cylinder chamber 40b and the piston block 40d of the piston rod 40a, a spring back is applied to the locking cylinder 40 as shown in an enlarged view in FIG. It does not occur (MAX 0 mm in the example shown).

  Subsequently, by removing the load from the upper mold 12 on the piston rod 48a of the passive cylinder 48, the pressure of the gas sealed in the cylinder chamber 48a2 (see FIG. 4A) below the passive cylinder 48 is used. The piston rod 48a is urged upward, and the gas stored in the cylinder chamber 48b1 above the passive cylinder 48 is pressurized.

At this time, in the present embodiment, the valve 54 of the valve block 56 is switched so that the discharge conduit 50 is closed, contrary to the state shown in FIG. Then, the gas stored in the cylinder chamber 48b1 above the passive cylinder 48 is directed to the cartridge valve 62 through the flow conduit 51 and the discharge conduit 52. Then, by opening the operation control valve 60 of the cartridge valve 62, the check valve 58 of the piston block 40d is closed, and the gas in the upper cylinder chamber 40b2 moves to the rod 40e, the inner rod 40f, and the operation. It moves to the lower cylinder chamber 40b1 via the control valve 60.
Therefore, the piston rod 40a is restroked from the time when the operation control valve 60 is opened, and as shown in FIG. Changes to. And piston rod 40a will return to a top dead center.

Based on the configuration of the gas supply / exhaust circuit 44 described above, the procedure of the composite press using the press apparatus 10 according to the embodiment of the present invention will be described with reference to FIGS.
The press device 10 according to the embodiment of the present invention includes an upper die 12 provided with a punching blade 16, a curved blade 18, and a hole punching pin 30, and these are moved up and down at an appropriate timing, whereby the lower die 14 is bent. As shown in FIG. 5, together with the blade 20 and the punch 36, the plate-like workpiece W is punched (S20), bent (S30), and punched (S40). The specific work flow is as follows. In addition, the following description will be given with reference to FIG.
FIG. 6A shows a stroke angle diagram in which each step of the flow of FIG. 5 is collated. Further, FIG. 6B shows a relational diagram of stroke operations of the upper mold 12 and the locking cylinder 40 with respect to time passage similar to FIG. 4B in the upper stage. 6B shows how the operation control valve 60 of the locking cylinder 40 is opened and closed with respect to time (time), and the lower part of FIG. 6B shows the opening and closing of the valve 54 of the valve block 56. Embodiments are shown.

S0 (top dead center; press angle 0 °): The plate-shaped workpiece W is set on the lower mold 14 in a state where the upper mold 12 is at the top dead center (see FIG. 10). At this time, air is supplied to the cartridge valve 62 of the locking cylinder 40, and the operation control valve 60 is switched to the open state (OPEN) as shown in the middle part of FIG. The cylinder rod 40a of the locking cylinder 40 is located at the top dead center. Therefore, the bending blade 20 of the lower mold 14 is supported by the locking cylinder 40 and is located at the top dead center. Further, as shown in FIG. 11, in the gas supply / exhaust circuit 44 at this time, the mechanical valve 64 is closed, the first operating valve 68 is in communication, and the second operating valve 70 is closed. The pressure of air (AIR (IN)) is applied to the operation control valve 60 of the locking cylinder 40 and the bottom dead center lock display plate 74. In the present embodiment, the state of the gas supply / exhaust circuit 44 shown in FIG. 11 is maintained up to the bottom dead center at a press angle of 180 °.
S10 (pad contact): As shown in FIG. 7A, the upper die 12 is lowered and the pad 34 is brought into contact with the plate-like workpiece W set on the lower die 14. Thereafter, the plate-like workpiece W is sandwiched between the pad 34 and the punch 36 under the load of the third gas cylinder 32.

S20 (start of extraction): The upper die 12 is further lowered from the state of FIG. 7A, and the extraction blade 16 is pressed against the plate-like workpiece W. At this time, since the second gas cylinder 28 contacts the spacer 34 a of the pad 34, the pad 34 also receives a load from the second gas cylinder 28. For this reason, the peripheral part of the hole formation part of the plate-shaped workpiece W is clamped by the pad 34 and the punch 36 with a higher load. Then, as shown in FIG. 7B, the plate-like workpiece W is punched by the punching blade 16 and the bending blade 20 of the lower mold 14. At this time, the bending blade 20 of the lower mold 14 is supported by the locking cylinder 40 and maintained at the top dead center.
S30 (beginning of bending): The upper die 12 is further lowered from the state of FIG. 7B, and the curved blade 18 is pressed against the plate-like workpiece W. At this time, a load is continuously applied from the second gas cylinder 28 and the third gas cylinder to the plate-like workpiece W, and the load of the first gas cylinder 24 is also applied. Then, as shown in FIG. 8A, the locking cylinder 40 also starts to descend, and the bending work 18 and the bending blade 20 cause the plate-like workpiece W to be bent. Further, for example, at a point before the bottom dead center of the curved blade 18 (as an example, −20 mm), the mechanical valve 64 contacts the descending curved blade 18 and the mechanical valve 64 is switched to an open state.

S40 (start of hole punching): The upper die is further processed from the state of FIG. 8A, and the hole punching pin 30 is pressed against the plate-like workpiece W. Then, in a state where a load is continuously applied from the first to third gas cylinders 24, 28, 32 to the plate-like workpiece W, as shown in FIG. The plate-shaped workpiece W is punched by the bending blade 20.
S50 (bottom dead center; press angle 180 °): The locking cylinder 40 of the lower die 14 is lowered to the bottom dead center of the movable range, and the bending blade 20 also reaches the bottom dead center at the same time. At this time, the piston rod 48a of the passive cylinder 48 is pushed down as the upper die 12 is lowered, and the cylinder chamber 48b1 is also formed above the piston block 48c of the piston rod 48a. The cylinder chamber 48b1 becomes negative pressure (see FIG. 4).

S60 (upper die lift, lower die unit lock): When the locking cylinder 40 reaches the bottom dead center, the gas supply / exhaust circuit 44, as shown in FIG. 12, the mechanical valve 64 is in the open state (OPEN), The 1 operating valve 68 is in a communicating state, and the second operating valve 70 is in an open state. Then, the pressure of air (AIR (IN)) is also applied to the valve 54 of the valve block 56, and the valve 54 of the valve block 56 is opened (OPEN) as shown in the lower part of FIG. 6B. It becomes. As a result, as described with reference to FIG. 4, the gas between the end surface 40 c of the cylinder chamber 40 b that defines the bottom dead center of the piston rod 40 a and the piston block 40 d of the piston rod 40 a flows into the cylinder chamber above the passive cylinder 48. It will be sucked into 48b1 and stored. Therefore, the residual gas between the end surface 40c of the cylinder chamber 40b and the piston block 40d of the piston rod 40a is completely removed.
Then, as shown in FIG. 9B, even if the load applied to the bending blade 20 is reduced by the upper mold 12 passing over the bottom dead center and starting to rise again, a spring is applied to the locking cylinder 40. The back does not occur, and the piston rod 40a and the bending blade 20 of the locking cylinder 40 are completely locked (0-locked) at the bottom dead center.

Further, as the upper die 12 is raised, the load from the upper die 12 on the piston rod 48a of the passive cylinder 48 is removed, and the cylinder chamber 48b2 (see FIG. 4A) below the passive cylinder 48 is sealed. The piston rod 48a is urged in the protruding direction by the pressure. Then, the gas temporarily stored in the cylinder chamber 48b1 above the passive cylinder 48 tends to be pushed out. However, at this time, the operation control valve 60 shuts off the cylinder chamber 40b1 and the inner rod 40f (see FIG. 4A), and the two cylinder chambers 40b1 through the rod 40e and the inner rod 40f, Communication between 40b2 is blocked, and the check valve 58 of the piston block 40d is closed. Therefore, the piston rod 40a is held at the bottom dead center of the stroke operation without ascending the cylinder chamber 40b. In addition, the gas temporarily stored in the cylinder chamber 48b1 above the passive cylinder 48 is blocked by the operation control valve 60, and is prevented from returning to the cylinder chamber 40b1 below the locking cylinder 40.
In the present embodiment, the state of the gas supply / exhaust circuit 44 shown in FIG. 12 is maintained during the press angle range of 180 ° to 220 °.

S70 (lower die unit rising start; press angle 220 °): As the upper die 12 is raised, the gas supply / exhaust circuit 44 is in a closed state and the first operating valve 68 is in communication as shown in FIG. In this state, the second operating valve 70 is opened to the atmosphere, and is not applied to both the operation control valve 60 of the locking cylinder 40 and the bottom dead center lock display plate 74. The pressure of air applied to the valve 54 of the valve block 56 is removed through the second operating valve 70 and the first operating valve 68 (AIR (OUT)).
As a result, as shown in the middle part of FIG. 6B, the operation control valve 60 of the cartridge valve 62 of the locking cylinder 40 is opened (OPEN), and as shown in the lower part of FIG. 54 becomes a closed state (CLOSE). Then, as described with reference to FIG. 4, the gas stored in the cylinder chamber 48 b 1 above the passive cylinder 48 goes to the cartridge valve 62 through the flow pipe 51 and the discharge pipe 52. Since the operation control valve 60 of the cartridge valve 62 is opened, the bottom dead center zero lock state is released, the check valve 58 of the piston block 40d is closed, and the upper cylinder chamber 40b2 is closed. The gas moves through the rod 40e, the inner rod 40f, and the operation control valve 60 to the lower cylinder chamber 40b1. At this time, the application of the load to the panel product W ′ with respect to the pad 34 is released due to the rise of the upper mold 12.
S80 (top dead center; press angle 360 °): The piston rod 40a of the locking cylinder 40 is restroked to return to the top dead center. Then, the panel product W ′ is ejected from the lower mold 14 to complete one press process (see FIG. 10).

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained.
That is, the pressing device 10 according to the embodiment of the present invention causes the cutting blade 16 and the curved blade 18 of the upper die 12 to be pressed at a predetermined pressing angle with respect to the plate-like workpiece W set on the lower die 14. A so-called composite press apparatus is configured to press and perform at least the punching process (S20) and the bending process (S30) in one press step together with the bending blade 20 of the lower die 14. Further, a locking cylinder 40 is used as a means for generating a stroke operation necessary for the bending blade 20 of the lower die 14, and the urging force from the piston rod 40 a of the locking cylinder 40 is bent by the bending blade 20. By receiving the stroke operation of the curved blade 16 of the upper mold 12 while acting on the blade 20, a corresponding stroke operation is given to the extracted blade 20 of the lower mold 14.

The piston rod 40a of the locking cylinder 40 is held at a position corresponding to the bottom dead center of the stroke operation of the bending blade 20 for a predetermined press angle range (180 ° to 220 °) after reaching the bottom dead center. (S60). As a result, even if the load applied to the bending blade 20 is reduced by the upper die 12 passing the bottom dead center and starting to rise again, the locking cylinder that has received the load and contracted the piston rod 40a until then. 40 does not stretch, and therefore the bending blade 20 does not rise.
Therefore, it is possible to prevent the panel product W ′ from being forcibly lifted by the ascent of the lower punching blade 20 (so-called “ka-up” state) and causing the panel product W ′ to be deformed.

  Further, the pressing device 10 according to the embodiment of the present invention has a locking cylinder as a holding means for holding the piston rod 40a of the locking cylinder 40 at a position corresponding to the bottom dead center of the stroke operation of the bending blade 20. 40 includes a gas supply / exhaust circuit 44 communicating with 40. Then, the gas in the rocking cylinder 40 is discharged through the gas supply / exhaust circuit 44, so that the piston rod 40a is moved through the stroke of the bending blade 20 during a predetermined press angle range (180 ° to 220 °). It can be held at a position corresponding to the bottom dead center of the movement.

Further, the external storage means 46 provided in the gas supply / exhaust circuit 44 includes an end face 40c and a piston rod 40a that define a bottom dead center at the bottom dead center of the stroke operation of the piston rod 40a in the cylinder chamber 40b of the locking cylinder 40. The gas remaining during the period can be temporarily discharged out of the rocking cylinder 40 and stored. The gas remaining between the end surface 40c defining the bottom dead center and the piston rod 40a is completely discharged from the cylinder chamber 40b, so that the upper die 12 passes the bottom dead center and starts to rise again. Even if the load applied to the bending blade 20 decreases, the rocking cylinder 40 can avoid the occurrence of springback caused by the residual gas in the cylinder chamber 40b (see FIG. 4B). . And it becomes possible to hold | maintain the piston rod 40a of the rocking cylinder 40 in the position corresponding to the bottom dead center of the stroke operation | movement of the bending blade 20 for a predetermined press angle range (180 degrees-220 degrees). .
In addition, the gas discharged from the cylinder chamber of the locking cylinder 40 is stored, and when the predetermined press angle range (220 °) is passed, the gas is returned to the locking cylinder 40, whereby the piston rod 40a is held. It becomes possible to cancel. In addition, by reducing the gas discharged from the cylinder chamber 40b of the locking cylinder 40, it is possible to prevent a decrease in gas necessary for the operation of the locking cylinder 40.

The press device 10 according to the embodiment of the present invention sucks the gas remaining between the end surface 40c of the cylinder chamber 40b of the locking cylinder 40 and the piston block 40d by the passive cylinder 48 of the external storage means 40. By generating the negative pressure to be obtained, the gas remaining between the end face 40c and the piston block 40d can be completely discharged from the cylinder chamber 40b1.
Further, between the cylinder chamber 40b1 (FIG. 3 (b)) formed between the end face 40c of the cylinder chamber 40a of the locking cylinder 40 and the piston block 40d and the passive cylinder 48, a discharge pipe 50 and a reflux pipe are provided. By communicating with the passage 52 (FIG. 4 (a)), it is possible to circulate gas between the cylinder chamber 40b1 and the passive cylinder 48.

  Moreover, the valve 54 provided in the discharge pipe 50 communicates the discharge pipe 50 until the curved blade 16 of the upper mold 12 reaches at least the bottom dead center of the stroke operation (press angle 0 ° to 180 °). By setting the state, the gas is circulated from the cylinder chamber 40 b 1 of the locking cylinder 40 to the passive cylinder 48. In addition, when the predetermined press angle range is passed (220 ° to), the discharge pipe 50 is closed by the valve 54, so that the passive cylinder 48 to the locking cylinder 40 are connected via the reflux pipe 52. It becomes possible to release the holding state of the piston rod by refluxing the gas.

  Further, the press device 10 according to the embodiment of the present invention includes cylinder chambers 40b1 and 40b2 that are separated in the stroke direction of the piston rod 40a by a gas exchange circuit (see FIGS. 3A to 3C) of the locking cylinder 40. The stroke operation of the piston rod 40a is made possible by performing gas exchange between them. In addition, the gas exchange circuit includes an operation control valve 60 for preventing gas exchange between the cylinder chambers 40b1 and 40b2 separated in the stroke direction of the piston rod 40a. The operation control valve 60 includes a return pipe of the external storage means 46. Since the passage 52 is connected, the piston rod 40a is maintained at a position corresponding to the bottom dead center of the stroke operation of the bending blade 20 by appropriately switching the operation control valve 60, or the maintenance state is maintained. It becomes possible to cancel.

In addition, both the valve 54 provided in the discharge pipe 50 of the external storage means 46 and the operation control valve 60 of the locking cylinder 40 are supplied via a mechanical valve 64 (FIGS. 2 and 11 to 13). The predetermined switching operation can be performed by receiving air. That is, the valve 54 provided in the discharge pipe 50 and the operation control valve 60 of the locking cylinder 40 are configured to perform the predetermined switching operation according to the operation of the upper mold 12.
As a means for causing the valve 54 provided in the discharge pipe 50 and the operation control valve 60 of the locking cylinder 40 to perform the predetermined switching operation, for example, instead of the above-described air drive, It is also possible to adopt a method in which an electric signal is received from the control system and operated by a solenoid valve.

  10: Press device, 12: Upper die, 14: Lower die, 16: Cutting blade, 18: Curved blade, 20: Curved blade, 40: Rocking cylinder, 40a: Piston rod, 40b, 40b1, 40b2: Cylinder chamber 40c: end face, 40d: piston block, 40e: rod, 40f: inner rod, 44: gas supply / exhaust circuit, 46: external storage means, 48: passive cylinder, 48a: piston rod, 48b, 48b1, 48b2: cylinder chamber, 50: discharge pipe, 52: reflux pipe, 54: valve, 56: valve block, 58: check valve, 60: operation control valve, 62: cartridge valve, 64: mechanical valve, 66: check valve, 68: 1st operated valve, W: Plate work, W ': Panel product

Claims (8)

A first mold comprising at least a cutting blade and a curved blade; and a second mold comprising at least a curved blade facing the curved blade of the first mold in the stroke direction;
The punching blade of the first die and the curved blade are brought into pressure contact with each other at a predetermined press angle to the plate-shaped workpiece set in the second die, and together with the bending blade of the lower die, A pressing device that performs at least a punching process and a bending process in one press process,
A gas cylinder that receives a stroke operation of the curved blade of the first type and applies a corresponding stroke operation to the bent blade of the second type, and a piston rod of the gas cylinder between a predetermined press angle range. And a holding means for holding at a position corresponding to the end position of the stroke operation of the bending blade. The press apparatus according to claim 1, wherein the holding unit includes a gas supply / exhaust circuit communicating with the gas cylinder. In the gas supply / exhaust circuit, gas remaining between the end surface defining the end point position and the piston rod at the end point position of the stroke operation of the piston rod in the cylinder chamber of the gas cylinder is supplied to the outside of the gas cylinder. The press apparatus according to claim 2, further comprising an external storage unit that temporarily discharges and stores the gas to the gas cylinder and appropriately returns the gas to the gas cylinder. The external storage means includes a storage cylinder that generates a negative pressure capable of sucking a gas remaining between the piston rod and an end surface of the cylinder chamber of the gas cylinder that defines an end position of stroke operation of the piston rod. ,
A discharge pipe and a reflux pipe communicating with a cylinder chamber formed between the end face of the cylinder chamber of the gas cylinder and defining an end point of stroke operation of the piston rod and the piston rod;
The said discharge pipe line contains the valve | bulb which makes the said discharge pipe line a communication state until the said curved blade of the said 1st type | mold reaches at least the end point position of stroke operation | movement. Press device. The gas cylinder includes a gas exchange circuit that exchanges gas between cylinder chambers separated in the stroke direction of the piston rod in accordance with the operation of the piston rod,
The gas exchange circuit includes an operation control valve for preventing gas exchange between cylinder chambers separated in the stroke direction of the piston rod,
The press apparatus according to claim 4, wherein the return conduit of the external storage means is connected to the operation control valve. A mechanical valve that switches according to the operation of the first type,
One or both of the valve provided in the discharge pipe of the external storage means and the operation control valve of the gas cylinder receive air supplied via the mechanical valve and perform a predetermined switching operation. The press apparatus according to claim 4 or 5, wherein Using a first mold that includes at least a punching blade and a curved blade, and a second mold that includes at least a bending blade facing the curved blade of the first mold in the stroke direction,
The punching blade of the first die and the curved blade are brought into pressure contact with each other at a predetermined press angle to the plate-shaped workpiece set in the second die, and together with the bending blade of the lower die, A pressing method in which at least a punching process and a bending process are performed in one press process,
A stroke operation corresponding to the stroke operation of the curved blade of the first type is applied to the bending blade of the second type using a gas cylinder, and the piston rod of the gas cylinder is placed within a predetermined press angle range. A pressing method, wherein the bending blade is restroked after being held at a position corresponding to the end position of the stroke operation of the bending blade. In the cylinder chamber of the gas cylinder, at the end position of the piston rod operating stroke, the gas remaining between the end surface defining the end position and the piston rod is temporarily discharged out of the gas cylinder and stored. By holding the gas cylinder piston rod at a position corresponding to the end position of the stroke operation of the bending blade for a predetermined press angle range, the gas temporarily stored outside the gas cylinder The press method according to claim 7, wherein the bending blade is restroked by appropriately returning to the gas cylinder.

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