JP2013035021A - Press forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press forming apparatus which can perform uniform management of gas pressure, can easily detect gas leakage, and can continue operation without requiring repair work even when the gas leakage occurs.SOLUTION: The press forming apparatus includes: a cushion pin body 250; a gas cylinder 251 including a piston rod 253 which is provided inside of the same body, and projected from the upper end to support a blank holder 23; a flow channel 254 which is extended downward from the bottom portion of the gas cylinder 251, and reaches a lower end part 250B; first and second fluidic valves 255, 256 which are provided sequentially from above in the middle of the flow channel 254, and allows only the flow of fluid from downward to upward; an auxiliary fluid chamber 257 provided between the fluidic valves; a quick joint 258 which is provided right under the flow channel 254 at the lower end part 250B, and connected to a branched channel 273; and an elastic member 259 which is provided to surround the quick joint 258 at the lower end part 250B, and supports the cushion pin body 250 between the cushion plate 27.

Description

  The present invention relates to a press molding apparatus. More specifically, the present invention relates to a press forming apparatus that forms a workpiece with a die and a punch while holding the workpiece with a blank holder.

  2. Description of the Related Art Conventionally, in a press forming apparatus, an end portion of a workpiece such as a steel plate is held with a blank holder, and in this state, drawing is performed to narrow down the workpiece with a die and a punch. At the time of molding, a uniform blank hold pressure is applied to the end portion of the work gripped by the blank holder in order to properly maintain the inflow amount of the work material and prevent the occurrence of wrinkles and cracks.

  As a pressure equalizing mechanism that equalizes the blank hold pressure, a mechanism in which an independent gas cylinder is provided for each of a plurality of cushion pins that support the blank holder is known. This pressure equalizing mechanism has an advantage that when a gas leak occurs, it is only necessary to replace the gas cylinder in which the gas leak has occurred. In addition, even if there is a height difference in the height of the tip surface of each cushion pin due to wear or the like due to long-term use, the height difference can be absorbed by the pressure equalizing mechanism, and the blank hold pressure can be made uniform. . However, there is a drawback that the gas pressure cannot be centrally managed and it is difficult to detect gas leakage.

  Therefore, a pressure equalizing mechanism has been proposed in which a gas cylinder having a two-stage structure is provided at the lower ends of a plurality of cushion pins that support the blank holder, and these gas cylinders are arranged in a cushion plate provided below the lower mold. (See Patent Document 1). In this pressure equalizing mechanism, each gas cylinder includes a first pressure chamber to which air for pressing the first piston is supplied and a second pressure chamber to which air for pressing the second piston is supplied. Has been. Further, the first pressure chambers communicate with each other and the second pressure chambers communicate with each other, so that a so-called manifold type pressure equalizing mechanism is obtained.

  According to the pressure equalizing mechanism of Patent Document 1, even if a height difference occurs in the height of the tip surface of each cushion pin due to wear due to long-term use, the height difference can be absorbed by the pressure equalizing mechanism, There is an advantage that the blank hold pressure can be made uniform. In addition, there is an advantage that gas pressure can be centrally managed and gas leakage can be easily detected.

JP 2008-173678 A

  However, the manifold-type pressure equalizing mechanism as disclosed in Patent Document 1 has a drawback in that when a gas leak occurs in one gas cylinder, the gas in all the gas cylinders is released. Usually, since the pressure equalizing mechanism is disposed below the lower mold, there is a drawback that the operation of the press molding apparatus must be stopped for repair work when a gas leak occurs.

  The present invention has been made in view of the above, and its purpose is that the gas pressure can be centrally managed, gas leakage can be easily detected, and even if a gas leakage occurs, operation can be performed without requiring repair work. It is to provide a press molding apparatus that can be continued.

  To achieve the above object, the present invention includes a punch (for example, a punch 21 described later), a die (for example, a later-described die 31) provided opposite to the punch and capable of moving forward and backward with respect to the punch, A blank holder (e.g., a later-described blank holder 23) that is provided so as to surround the punch and grips an end of a work (e.g., a later-described steel plate 10), and a plurality of cushion pins (e.g., a later-described blank holder 23). A press molding apparatus (for example, a press molding apparatus 1 described later) including a cushion pin (described later) and a cushion plate (for example, a cushion plate 27 described below) that supports the cushion pin is provided. In the press molding apparatus according to the present invention, the cushion plate is supplied with a fluid (for example, a gas to be described later) supplied from a fluid supply means (for example, a gas supply unit 40 to be described later). And a cushion pin body (for example, a cushion pin body 250 described later) and an upper end (for example, an upper end 250A described later) of the cushion pin body. ) And a fluid cylinder (for example, a gas cylinder 251 described later) including a piston rod (for example, a piston rod 253 described later) that protrudes from the bottom of the fluid cylinder, and extends downward from the bottom of the fluid cylinder. A flow path (for example, a flow path 2 to be described later) reaching a lower end portion (for example, a lower end section 250B to be described later). 4) and a first fluid valve (for example, a first fluid valve 255 described later) and a second fluid valve (for example, described later) that are provided in the middle of the flow path in order from the top and allow only the fluid flow from the bottom to the top. , A second fluid valve 256 described later), and an auxiliary fluid chamber (for example, an auxiliary fluid chamber 257 described later) provided between the first fluid valve and the second fluid valve and constituting a part of the flow path. And a quick joint (for example, a quick joint 258 described later) connected to a branch path (for example, a branch path 273 described later) that is provided directly below the flow path at the lower end of the cushion pin main body and branched from the supply path. ) And an elastic member (for example, an elastic portion described later) that is provided so as to surround the quick joint at a lower end portion of the cushion pin body and supports the cushion pin body between the cushion plate and the cushion plate body. 259), and the flow path is formed such that a front end portion thereof (for example, a front end portion 254A described later) can be engaged with the quick joint, and the quick joint is moved to the blank as the die is lowered. When the holder is lowered, the cushion pin main body is pressed downward via the piston rod, the elastic member contracts, and the cushion pin main body is lowered to engage with the tip of the flow path, Thereby, the fluid is introduced into the flow path.

  According to the present invention, first, when the blank holder descends as the die descends, the cushion pin body is pressed downward via the piston rod. Then, the elastic member contracts and the cushion pin main body descends, so that the quick joint provided immediately below the flow channel engages with the tip of the flow channel. Thereby, the fluid supplied from the fluid supply means is introduced into the flow path via the supply path and the branch path. When the fluid is introduced into the flow path, the pressure inside the flow path on the lower side of the second fluid valve becomes higher than the pressure in the auxiliary fluid chamber on the upper side, so that the second fluid valve opens and the fluid is introduced into the auxiliary fluid chamber. Is done. At this time, the piston is pressed downward via the piston rod, and the fluid cylinder internal pressure becomes higher than the auxiliary fluid chamber internal pressure, so that the first fluid valve remains closed.

  Next, after the die reaches the bottom dead center, the die is lifted, so that the downward pressing force applied to the cushion pin body through the blank holder and the piston rod is gradually eliminated. Then, the elastic member is restored by its elastic force to press the cushion pin main body upward, and the cushion pin main body is raised, so that the engagement between the quick joint and the tip of the flow path is released. Thereby, the introduction of the fluid from the quick joint into the flow path is stopped, and the flow path internal pressure on the lower side of the second fluid valve becomes lower than the auxiliary fluid chamber pressure on the upper side, whereby the second fluid valve is closed. . At this time, since the downward pressing force applied to the piston via the piston rod is gradually eliminated, the blank holder is raised by raising the piston and the piston rod relative to the cushion pin body. Finally, it returns to the original height position. Here, if a gas leak has occurred in the fluid cylinder, the fluid cylinder internal pressure becomes lower than the auxiliary fluid chamber pressure, so that the first fluid valve opens, and the fluid is replenished from the auxiliary fluid chamber into the fluid cylinder. Is done. That is, even in a fluid cylinder in which a gas leak has occurred, a cylinder internal pressure equivalent to that of a fluid cylinder in which no gas leak has occurred is maintained. As a result, even in a fluid cylinder in which gas leakage has occurred, the blank holder rises by raising the piston and the piston rod relative to the cushion pin body in the same manner as in the fluid cylinder in which no gas leakage has occurred. Finally, it returns to the original height position.

  Next, after the molded product is taken out and a new workpiece is set, when the blank holder is lowered again as the die is lowered, the first fluid valve is kept until the fluid cylinder pressure becomes higher than the auxiliary fluid chamber pressure. Will remain open. At this time, the fluid cylinder in which the gas leak has occurred is replenished with fluid from the auxiliary fluid chamber, so that the cylinder internal pressure equivalent to that of the fluid cylinder in which no gas leak has occurred is maintained. Thereby, even when gas leakage occurs, the blank hold pressure is maintained uniformly.

Therefore, according to the present invention, even when a gas leak occurs in the fluid cylinder, the fluid cylinder is replenished with each press stroke, so that the pressure in the fluid cylinder can be reduced without stopping the operation of the press molding apparatus. The blank hold pressure can be made uniform. That is, even when a gas leak occurs, the operation of the press molding apparatus can be continued without requiring repair work.
Further, according to the present invention, the fluid pressure is replenished in each fluid cylinder via the branch passage branched from the supply passage, so that the gas pressure can be managed centrally, and even if some gas leaks, The pressure in the fluid cylinder does not drop.
Moreover, according to this invention, a gas leak can be easily detected by detecting the opening degree of a 1st fluid valve and a 2nd fluid valve.

  In this case, a leak detection means (for example, a leak described later) detects the fluid leak by detecting at least one of the opening degree of the first fluid valve and the second fluid valve and the flow rate of the fluid passing through the fluid valve. Preferably it further comprises a sensing device 50).

  According to the present invention, gas leakage can be detected with a simple device configuration by detecting at least one of the opening degree of the first fluid valve and the second fluid valve and the flow rate of the fluid passing through these fluid valves.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to manage gas pressure centrally and detecting a gas leak easily, even when a gas leak generate | occur | produces, the press molding apparatus which can continue operation | movement without requiring a repair operation can be provided.

It is a longitudinal cross-sectional view of the press molding apparatus which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view of a cushion pin when the blank holder is descending. It is a longitudinal cross-sectional view of the cushion pin when the blank holder is rising.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A press forming apparatus according to an embodiment of the present invention performs drawing by narrowing a work with a die and a punch while holding an end of a steel plate as a work with a blank holder.

FIG. 1 is a longitudinal sectional view of a press forming apparatus 1 according to the present embodiment.
The press forming apparatus 1 includes a lower mold mechanism 20 that is disposed on the lower side of the steel plate 10 and supports the steel sheet 10, an upper mold mechanism 30 that is disposed on the upper side of the steel plate 10 and can be advanced and retracted with respect to the lower mold mechanism 20, The gas supply part 40 as a fluid supply means and the leak detection apparatus 50 as a leak detection means are provided.
The lower mold mechanism 20 and the upper mold mechanism 30 are disposed to face each other with the steel plate 10 interposed therebetween.

  The lower mold mechanism 20 includes a punch 21, a blank holder 23, a cushion pin 25, and a cushion plate 27.

The punch 21 is fixed on the bolster 211.
The punch 21 has a molding surface 213 corresponding to the shape of the molded product, and the cross-sectional shape thereof is an upward convex curve. The punch 21 abuts on the lower surface of the central portion of the steel plate 10 during forming and narrows the steel plate 10 with a die 31 described later, thereby forming the steel plate 10 into a shape corresponding to the forming surface 213.

The blank holder 23 is annularly provided so as to surround the punch 21. The blank holder 23 is supported by a plurality of cushion pins 25 described later, and can be moved up and down relatively with respect to the punch 21.
The blank holder 23 holds the end portion of the steel plate 10 together with the flange portion 311 of the die 31 described later.

A plurality of cushion pins 25 are provided, and support the blank holder 23 so that it can move up and down relatively with respect to the punch 21.
FIG. 2 is a longitudinal sectional view of the cushion pin 25. In addition, in FIG. 2, the state when the blank holder 23 is falling is shown. As shown in FIG. 2, the cushion pin 25 includes a cushion pin body 250, a gas cylinder 251, a flow path 254, a first fluid valve 255, a second fluid valve 256, an auxiliary fluid chamber 257, and a quick joint. 258 and an elastic member 259.

  The cushion pin main body 250 has a cylindrical shape extending in a substantially vertical direction, and includes a gas cylinder 251, a flow path 254, a first fluid valve 255, a second fluid valve 256, an auxiliary fluid chamber 257, and the like, which will be described later. Yes.

The gas cylinder 251 is provided in the upper part of the cushion pin main body 250.
The gas cylinder 251 includes a piston 252 that slides inside the cylinder, and a piston rod 253 that is connected to the piston 252 and protrudes from the upper end 250 </ b> A of the cushion pin main body 250 to support the blank holder 23.
The gas cylinder 251 presses the blank holder 23 upward via the piston rod 253.

The flow path 254 extends downward from the bottom of the gas cylinder 251 and is provided so as to reach the lower end 250B of the cushion pin body 250.
The tip 254A of the flow channel 254 has a shape that can be engaged with a quick joint 258 described later. As a result, the flow path 254 has its tip 254A engaged with the quick joint 258, so that gas supplied via a supply path 271 and a branch path 273, which will be described later, is supplied to the auxiliary fluid chamber 257 and the gas cylinder 251. Introduce.

The first fluid valve 255 and the second fluid valve 256 are provided in this order from above in the middle of the flow path 254. That is, the first fluid valve 255 is disposed in the flow path 254 above the second fluid valve 256.
Both the first fluid valve 255 and the second fluid valve 256 allow only the gas flow from the lower side to the upper side. That is, these fluid valves are constituted by check valves that prohibit gas flow from above to below.

The auxiliary fluid chamber 257 is provided between the first fluid valve 255 and the second fluid valve 256 and constitutes a part of the flow path 254.
When the second fluid valve 256 is opened in the auxiliary fluid chamber 257, gas supplied via a supply path 271 and a branch path 273, which will be described later, is introduced. The gas introduced into the auxiliary fluid chamber 257 is introduced into the gas cylinder 251 when the first fluid valve 255 is opened.

The quick joint 258 is provided at a lower end portion 250 </ b> B of the cushion pin main body 250 and immediately below the flow path 254. The quick joint 258 is connected to each branch path 273 branched from a supply path 271 described later.
The quick joint 258 can be engaged with the distal end 254 </ b> A of the flow path 254. In the quick joint 258, when the blank holder 23 descends as the die 31 described later descends, the cushion pin body 250 is pressed downward via the piston rod 253, and the elastic member 259 contracts, and the cushion pin body 250 Is lowered, it engages with the tip 254A of the flow path 254. Thereby, the gas supplied via the supply path 271 and the branch path 273 which will be described later is introduced into the flow path 254.

The elastic member 259 is provided in an annular shape so as to contact the lower surface of the annular convex portion 250 </ b> C formed at the lower end portion 250 </ b> B of the cushion pin main body 250 and surround the quick joint 258. As the elastic member 259, for example, urethane rubber is used.
When the blank holder 23 descends with the lowering of the die 31 described later, the elastic member 259 contracts by the cushion pin body 250 being pressed downward via the piston rod 253. Further, when the die 31 is raised, the downward pressing force applied to the cushion pin main body 250 via the blank holder 23 and the piston rod 253 is eliminated, and the die 31 is restored by its elastic force.

The cushion plate 27 is disposed below the punch 21 along the substantially horizontal direction, and supports the plurality of cushion pins 25.
The cushion plate 27 includes a single supply path 271 through which gas supplied from a gas supply unit 40 described later flows. In the supply path 271, branch paths 273 branched from the supply path 271 are provided according to the number of cushion pins 25.

Returning to FIG. 1, the upper mold mechanism 30 includes a die 31 and a lifting mechanism (not shown) that lifts and lowers the die 31.
The die 31 is disposed to face the punch 21 with the steel plate 10 interposed therebetween.
The die 31 has a forming surface 313 corresponding to the shape of the forming surface 213 of the punch 21, abuts against the upper surface of the central portion of the steel plate 10 during forming, and narrows the steel plate 10 with the punch 21, thereby reducing the steel plate 10. Is formed into a shape corresponding to the shape of the forming surface 313.
A flange portion 311 protruding downward is provided at the end portion of the die 31, and sandwiches the end portion of the steel plate 10 together with the blank holder 23.

The gas supply unit 40 includes a gas cylinder 41 and an accumulator 43.
The gas cylinder 41 is connected to the accumulator 43 and supplies gas as a fluid to the accumulator 43.
The accumulator 43 has one side connected to the gas cylinder 41 and the other side connected to the supply path 271. The accumulator 43 stores the gas supplied from the gas cylinder 41 in a high-pressure state, and in response to the opening of the second fluid valve 256, the accumulator 43 has a gas flow rate equal to or higher than the gas supply amount of the gas cylinder 41 to gas in the supply passage 271. Supply.

  The leak detection device 50 detects a gas leak by detecting the opening degrees of the first fluid valve 255 and the second fluid valve 256. The leak detection device 50 is electrically connected to the first fluid valve 255 and the second fluid valve 256 provided in each gas cylinder 251, detects the opening degree of these fluid valves, and based on the detection result The presence or absence of gas leakage in each gas cylinder 251 is detected.

The press forming apparatus 1 having the above-described configuration operates as follows, and the following effects are exhibited.
According to this embodiment, first, when the blank holder 23 descends as the die 31 descends, the cushion pin body 250 is pressed downward via the piston rod 253. Then, the elastic member 259 contracts and the cushion pin main body 250 descends, so that the quick joint 258 provided immediately below the flow path 254 engages with the tip 254A of the flow path 254. As a result, the gas supplied from the gas supply unit 40 is introduced into the flow path 254 via the supply path 271 and the branch path 273. When the gas is introduced into the flow path 254, the flow path internal pressure on the lower side of the second fluid valve 256 becomes higher than the internal pressure of the auxiliary fluid chamber 257 on the upper side, so that the second fluid valve 256 opens, and the auxiliary fluid Gas is introduced into the chamber 257. At this time, the piston 252 is pressed downward via the piston rod 253, and the internal pressure of the gas cylinder 251 becomes higher than the internal pressure of the auxiliary fluid chamber 257, so that the first fluid valve 255 remains closed.

  Next, after the die 31 reaches the bottom dead center, the die 31 is raised, so that the downward pressing force applied to the cushion pin body 250 via the blank holder 23 and the piston rod 253 is gradually eliminated. The Then, the elastic member 259 is restored by its elastic force to press the cushion pin main body 250 upward, and the cushion pin main body 250 is lifted, so that the quick joint 258 and the tip 254A of the flow path 254 are engaged. Is released. As a result, the introduction of gas from the quick joint 258 into the flow path 254 is stopped, and the flow path internal pressure on the lower side of the second fluid valve 256 becomes lower than the internal pressure of the auxiliary fluid chamber 257 on the upper side. The two fluid valve 256 closes. At this time, the downward pressing force applied to the piston 252 via the piston rod 253 is gradually eliminated, so that the piston 252 and the piston rod 253 rise relative to the cushion pin main body 250. The blank holder 23 rises and finally returns to the original height position. In addition, here, when a gas leak has occurred in the gas cylinder 251, the internal pressure of the gas cylinder 251 becomes lower than the internal pressure of the auxiliary fluid chamber 257, so that the first fluid valve 255 is opened and the auxiliary fluid chamber 257 Gas is replenished in the gas cylinder 251. That is, even in the gas cylinder 251 in which the gas leak has occurred, the cylinder internal pressure equivalent to the gas cylinder 251 in which no gas leak has occurred is maintained. Thereby, even in the gas cylinder 251 in which the gas leak has occurred, the piston 252 and the piston rod 253 are relatively raised with respect to the cushion pin main body 250 in the same manner as the gas cylinder 251 in which no gas leak has occurred. The blank holder 23 rises and finally returns to the original height position.

  Next, when the molded product is taken out, a new steel plate 10 is set, and the blank holder 23 is lowered again as the die 31 is lowered, the internal pressure of the gas cylinder 251 becomes higher than the internal pressure of the auxiliary fluid chamber 257. Until then, the first fluid valve 255 remains open. That is, the gas cylinder 251 in which gas leakage has occurred is supplemented with gas from the auxiliary fluid chamber 257, and as a result, the cylinder internal pressure equivalent to that of the gas cylinder 251 in which no gas leakage has occurred is maintained. Thereby, even when gas leakage occurs, the blank hold pressure is maintained uniformly.

Therefore, according to this embodiment, even when a gas leak occurs in the gas cylinder 251, the gas is replenished in the gas cylinder 251 at every press stroke, so that the gas does not stop operation of the press molding apparatus 1. The pressure in the cylinder 251 can be maintained, and the blank hold pressure can be made uniform. That is, even when a gas leak occurs, the operation of the press molding apparatus 1 can be continued without requiring repair work.
In addition, according to the present embodiment, gas is replenished into each gas cylinder 251 via the branch path 273 branched from the supply path 271, so that the gas pressure can be managed centrally and a gas leak occurs in part. However, the pressure in all the gas cylinders 251 does not decrease.

  In addition, according to the present embodiment, the opening degree of the first fluid valve 255 and the second fluid valve 256 is detected, and the leakage detection device 50 that detects the gas leakage based on the detection result is provided, thereby simplifying the operation. Gas leakage can be easily detected with the device configuration.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
For example, in the above embodiment, the gas leakage is detected by detecting the opening degrees of the first fluid valve 255 and the second fluid valve 256, but the present invention is not limited to this. Gas leakage may be detected by providing a gas flow rate sensor in the flow path 254 and detecting the flow rate of the gas passing through the first fluid valve 255 and the second fluid valve 256.

DESCRIPTION OF SYMBOLS 1 ... Press molding apparatus 10 ... Steel plate (workpiece)
DESCRIPTION OF SYMBOLS 21 ... Punch 23 ... Blank holder 25 ... Cushion pin 250 ... Cushion pin main body 250A ... Upper end 250B ... Lower end part 251 ... Gas cylinder (fluid cylinder)
253 ... Piston rod 254 ... Flow path 254A ... Tip portion 255 ... First fluid valve 256 ... Second fluid valve 257 ... Auxiliary fluid chamber 258 ... Quick joint 259 ... Elastic member 27 ... Cushion plate 271 ... Supply passage 273 ... Branch passage 31 ... Die 40 ... Gas supply part (fluid supply means)
50 ... Leak detection device (leak detection means)

Claims (2)

Punch and
A die provided facing the punch and capable of advancing and retreating with respect to the punch;
A blank holder that is provided so as to surround the punch and grips an end of the workpiece;
A plurality of cushion pins for supporting the blank holder;
In a press molding apparatus comprising a cushion plate that supports the cushion pin,
The cushion plate includes therein a supply path through which a fluid supplied from the fluid supply means flows,
The cushion pin includes a cushion pin body,
A fluid cylinder including a piston rod provided in the cushion pin body and protruding from an upper end of the cushion pin body to support the blank holder;
A flow path extending downward from the bottom of the fluid cylinder to the lower end of the cushion pin body,
A first fluid valve and a second fluid valve that are provided in order from above in the middle of the flow path and allow only a fluid flow from below to above;
An auxiliary fluid chamber provided between the first fluid valve and the second fluid valve and constituting a part of the flow path;
A quick joint connected to a branch path branched from the supply path, provided immediately below the flow path at the lower end of the cushion pin body;
An elastic member provided so as to surround the quick joint at a lower end portion of the cushion pin main body, and supporting the cushion pin main body with the cushion plate;
The flow path is formed such that a tip portion thereof can be engaged with the quick joint,
In the quick joint, when the blank holder descends as the die descends, the cushion pin body is pressed downward via the piston rod, and the elastic member contracts, and the cushion pin body descends. Thus, the press molding apparatus is characterized in that the fluid is introduced into the flow path by engaging with the tip of the flow path. In the press molding apparatus according to claim 1,
The press further comprising a leak detecting means for detecting a fluid leak by detecting at least one of the opening degree of the first fluid valve and the second fluid valve and the flow rate of the fluid passing through the fluid valve. Molding equipment.

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