JP2013066931A - Press device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press device capable of improving descending speed of a movable mold by simple improvement to a device, and capable of shortening cycle time required for press machining.SOLUTION: The press device 1 includes a fixed mold 31, the movable mold 32 lifted and lowered with respect to the fixed mold 31, a lifting cylinder 51 for lifting and lowering the movable mold 32 by a hydraulic pressure, a pump 42 for operating the lifting cylinder 51, and a tank 41 for storing hydraulic fluid O. A bypass pipe 513 for making the hydraulic fluid O in the tank 41 flow out without passing through the pump 42 is connected to a head side port of the lifting cylinder 51. The lifting cylinder 51 is constituted so that a piston rod 516 strokes downward by receiving the own weight W of the movable mold 32, by the hydraulic fluid O flowing from the bypass pipe 513.

Description

  The present invention relates to a press apparatus that presses a material by lowering a movable mold relative to a fixed mold.

When pressing a material using a fixed mold and a movable mold, the movable mold is lowered by a hydraulic cylinder because a large output is easily obtained. Then, pressurized hydraulic fluid is sent from the hydraulic pump to the hydraulic cylinder, and the movable type is lowered and the material is pressurized by the movable type and the fixed type by the stroke operation of the hydraulic cylinder.
In addition, for example, in the heavy load lifting / lowering drive device of Patent Document 1, a hydraulic cylinder that lifts and lowers a heavy load, a hydraulic pump connected to the head side port of the hydraulic cylinder, and a rod side port of the hydraulic cylinder are connected. In addition to the variable displacement hydraulic motor, an accumulator and an auxiliary pump are used. When a heavy object is lifted, the required energy is supplied to the rod side port of the hydraulic cylinder from the accumulator previously accumulated by the auxiliary pump. The potential energy is recovered by the accumulator. This greatly reduces energy consumption with a simple configuration.

JP-A-11-2212

However, a conventional press device is not sufficient for a work (molded product) having a large required forming force and a work requiring deep drawing.
That is, for a workpiece having a large required forming force, it is necessary to increase the bore diameter of a hydraulic cylinder (hydraulic cylinder) or increase the number of hydraulic cylinders. For workpieces that require deep drawing, it is necessary to increase the open height (distance between the upper and lower molds) in order to put in and out the workpiece. For this reason, the movable stroke in the press apparatus increases, making it difficult to perform rapid pressing.
Further, it is considered that the tact required for press working can be shortened by increasing the capacity of the hydraulic pump, but in this case, the hydraulic unit becomes large.

  The present invention has been made in view of such a background, and provides a press device capable of improving the moving-down speed and reducing the tact required for press processing by an extremely simple device. It was obtained by trying.

The present invention includes a fixed mold fixed to a gantry,
A movable mold that is guided in a vertical direction by a guide portion disposed on the gantry and moves up and down relative to the fixed mold;
An elevating cylinder for elevating the movable mold;
A pump that sends hydraulic oil to the lift cylinder to operate the lift cylinder;
A tank connected to the pump and storing the hydraulic fluid,
A bypass pipe is connected to the head side port of the elevating cylinder to let the hydraulic oil in the tank flow out without going through the pump.
The raising / lowering cylinder is in a press apparatus configured to cause the piston rod to stroke downward by receiving the weight of the movable type by hydraulic oil flowing in from the bypass pipe (Claim 1).

The press device is devised to increase the lowering speed of the movable type by providing a bypass pipe in the head side port of the lifting cylinder in a configuration including a fixed type, a movable type, a lifting cylinder, a pump and a tank. .
Specifically, the bypass pipe is provided so as to connect the head side port of the elevating cylinder and the tank. The bypass pipe can cause the hydraulic oil in the tank to flow out to the head side port of the elevating cylinder without passing through the pump. Further, the lifting cylinder can move the piston rod downward by receiving the movable weight by the hydraulic oil flowing from the bypass pipe.

When pressing the workpiece with the press device, hydraulic fluid is returned from the rod side port of the lifting cylinder to the tank, and hydraulic fluid discharged from the tank by the pump to the head side port of the lifting cylinder. And hydraulic oil flowing out from the tank via the bypass pipe flows in.
Thereby, using the gravity which acts on a movable mold | type, the piston rod in a raising / lowering cylinder strokes below rapidly, and a movable mold | type can be rapidly lowered | hung toward a fixed mold | type. In addition, the movable descent speed can be improved by a very simple device on the apparatus that a bypass pipe is provided. Therefore, the tact (cycle time) required for press working can be shortened.

  Therefore, according to the press apparatus, the moving-down speed can be improved and the tact required for press working can be shortened by a very simple device.

Explanatory drawing which shows the structure of the press apparatus concerning an Example typically. Explanatory drawing which shows the press apparatus in an original position concerning the Example in the state seen from the front. Explanatory drawing which shows the press apparatus in a process position concerning the Example in the state seen from the side surface. The circuit diagram which shows roughly the hydraulic circuit of the press apparatus of the state which moved to the processing position from the original position concerning an Example. The circuit diagram which shows roughly the hydraulic circuit of the press apparatus of the state which moved to the original position from the process position concerning an Example.

A preferred embodiment of the above-described press apparatus will be described.
In the press apparatus, a driven type that is pushed by the movable mold and descends toward the fixed mold is disposed between the fixed mold and the movable mold. The movable type and the driven type may be continuously lowered by the hydraulic oil flowing in from the piping and the hydraulic oil sent from the pump (claim 2).
In this case, when a multi-stage press apparatus that simultaneously presses a plurality of workpieces using a driven type is configured, the lowering speed of the movable type and the driven type is improved by using the bypass pipe. The tact required for pressing can be shortened.

The rod side pipe is provided with a flow rate adjusting mechanism for adjusting the flow rate of the hydraulic oil flowing out from the lifting cylinder to the rod side pipe when the movable mold is lowered. The movable type may be configured to adjust the descending speed (Claim 3).
In this case, the flow rate adjustment mechanism can be adjusted to appropriately adjust the movable lowering speed due to the downward stroke of the piston rod in the elevating cylinder. Further, by adjusting the flow rate adjusting mechanism, it is possible to prevent the movable lowering speed from becoming too fast due to the hydraulic oil flowing out from the tank to the bypass pipe.

A plurality of the lifting cylinders are arranged in alignment with the movable mold, and the rod-side pipes connected to the plurality of lifting cylinders are connected to the lifting cylinders from the lifting cylinders. A flow balance mechanism that equalizes the flow rate of the hydraulic oil flowing out to the rod side pipe is provided, and the hydraulic fluid flows into the head side port of each lifting cylinder when the movable mold is lowered by the flow rate balance mechanism. The flow rate may be made uniform (claim 4).
In this case, when using a plurality of lifting cylinders to which bypass piping is applied, it is possible to prevent an eccentric load from being applied to the movable mold from the plurality of lifting cylinders. The movable mold can be lowered vertically while maintaining the horizontal balance with respect to the fixed mold.

In addition to the elevating cylinder, the pressing device includes a pressurizing cylinder that applies pressure to the movable mold that overlaps the fixed mold, and the pump sends hydraulic oil to the pressurizing cylinder. (Claim 5).
In this case, a lifting cylinder is used when moving up and down a movable type (or movable type and driven type) that does not require a large force, and a lifting cylinder and a pressure cylinder are used when pressing a workpiece that requires a large pressure. Can be used in combination.

Hereinafter, embodiments of the press apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 2 is a diagram illustrating the press device 1 at the original position 101 as viewed from the front, and FIG. 3 is a diagram illustrating the press device 1 at the processing position 102 as viewed from the side.
As shown in each drawing, the press device 1 of this example includes a fixed die 31, a movable die 32 that is guided in the vertical direction H by the guide portion 21 and moves up and down with respect to the fixed die 31, and the movable die 32 by hydraulic pressure. A lifting cylinder 51 that moves up and down, a pump 42 that sends hydraulic oil O to the lifting cylinder 51 and operates the lifting cylinder 51, and a tank 41 that is connected to the pump 42 and stores the hydraulic oil O are provided.

FIG. 1 is a diagram schematically illustrating the configuration of the movable die 32, the lifting cylinder 51, the pump 42, the tank 41, and the like in the press device 1. In the figure, a movable mold 32 and driven molds 33A to 33D described later are simply shown as heavy objects W.
As shown in the figure, the head side port of the lifting cylinder 51 is connected to the pump 42 by a head side pipe 511, and the rod side port of the lifting cylinder 51 is connected to the pump 42 by a rod side pipe 512. A bypass pipe 513 that allows the hydraulic oil O in the tank 41 to flow out without passing through the pump 42 is connected to the head side port of the elevating cylinder 51. The elevating cylinder 51 is configured to receive the dead weight W of the movable mold 32 by the hydraulic oil O flowing from the bypass pipe 513 and to stroke the piston rod 516 downward.

Below, it demonstrates in detail with reference to FIGS. 1-5 about the press apparatus 1 of this example.
As shown in FIGS. 2 and 3, in the press device 1 of this example, driven dies 33 </ b> A to 33 </ b> D that are pushed by the movable die 32 and descend toward the fixed die 31 are disposed between the fixed die 31 and the movable die 32. This is a multi-stage press apparatus 1 that is arranged and simultaneously presses a plurality of workpieces. In this example, four driven dies 33 </ b> A to 33 </ b> D are used in addition to the fixed die 31 and the movable die 32 in order to simultaneously press the three workpieces.
The elevating cylinder 51 of this example is configured to continuously lower the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D by the hydraulic oil O flowing from the bypass pipe 513 and the hydraulic oil O sent from the pump 42. Yes.

The press device 1 fixes a fixed die 31 to the head 2 as the lower part of the main body structure, and fixes the elevating cylinder 51 to the upper part of the crown 26 as the upper part of the main body structure with the rod side facing downward. A movable base 22 having a movable mold 32 is disposed at the lower end of the rod. The movable mold 32 is disposed on the lower surface of the movable base 22. Also, driven bases 23A and 23B are provided between the movable mold 32 and the fixed mold 31 and below the movable base 22, with the driven molds 33A to 33D disposed on the upper and lower surfaces. The driven bases 23A and 23B in this example are an upper driven base 23A in which driven surfaces 33A and 33B are disposed on the upper surface and the lower surface, and a lower driven base 23B in which driven surfaces 33C and 33D are disposed on the upper and lower surfaces. Are arranged in two upper and lower stages.
The movable base 22 and the driven bases 23A, 23B are configured to slide while being guided in the vertical direction H by the guide portions 21 disposed in four directions in the plane direction of the head 2 and the crown 26.

The two upper and lower driven bases 23A and 23B are urged upward by the urging means 24 (see FIGS. 4 and 5).
As shown in FIG. 2, the movable base 22 and the driven bases 23 </ b> A and 23 </ b> B are engaged with each other by the connecting member 25 so as to maintain a predetermined distance therebetween at the original position 101 of the press device 1.
At the original position 101 of the press apparatus 1 where the movable mold 32 is most elevated, the upper follower base 23A is urged upward by the urging means 24, and the movable mold 32 disposed on the lower surface of the movable base 22 A predetermined space (open height) S is formed between the first driven type 33A disposed on the upper surface of the upper driven base 23A. Further, at the original position 101 of the press apparatus 1, the lower driven base 23B is urged upward by the urging means 24, and the second driven mold 33B disposed on the lower surface of the upper driven base 23A A predetermined space S is formed between the lower driven base 23B and the third driven mold 33C disposed on the upper surface. Further, at the original position 101 of the press apparatus 1, there is a gap between the fourth driven mold 33 </ b> D disposed on the lower surface of the lower driven base 23 </ b> B and the fixed mold 31 disposed on the lower upper surface of the head 2. A predetermined space S is formed.

  When the movable base 22 and the movable mold 32 are lowered, the upper driven base 23A is pushed downward by the movable mold 32 and lowered, and the lower driven base 23B is pushed downward by the upper driven base 23A. To do. The upper work is sandwiched between the movable mold 32 and the first driven mold 33A and pressed, and the middle work is placed between the second driven mold 33B and the third driven mold 33C. The lower workpiece is sandwiched and pressed between the fourth driven die 33D and the fixed die 31.

  As shown in FIG. 2, the pump 42 and the tank 41 are arranged so that the hydraulic oil O in the tank 41 easily flows down to the head side port of the lift cylinder 51 via the bypass pipe 513. Are disposed at approximately the same height. The pump 42 and the tank 41 are disposed on the upper part of the work platform 20 that allows the worker to ascend and descend during maintenance or the like.

A plurality (four in this example) of the lifting cylinders 51 in this example are arranged in alignment with the movable base 22. The elevating cylinder 51 is configured such that the piston rod 516 double-acts within the cylinder body 517 by hydraulic pressure (see FIG. 1). The elevating cylinder 51 is disposed at a position symmetrical to the horizontal direction B and the depth direction D with respect to the horizontal center portion of the movable mold 32, and the lower end portion of the rod of each elevating cylinder 51 is the movable base 22. It is fixed to the upper surface of the.
As shown in FIG. 3, in addition to the plurality of elevating cylinders 51, the pressing device 1 applies a pressing force to the movable die 32 that overlaps the fixed die 31 and the driven dies 33A to 33D, and uses a plurality of pressure devices. One pressure cylinder 52 is provided.

As shown in the figure, in this example, a toggle mechanism 53 is used to effectively increase the pressure applied by the pressure cylinder 52. Then, the pressure applied by the pressure cylinder 52 is increased by the toggle mechanism 53 and transmitted to the movable mold 32.
The toggle mechanism 53 is configured using a pair of upper and lower links 531, and uses the lever principle when the pair of upper and lower links 531 changes from a vertically folded state to a vertically extending state. A large force is applied to the movable mold 32. The pressure cylinder 52 and the pair of upper and lower links 531 are disposed at symmetrical positions in the left-right direction B with respect to the central portion of the movable mold 32 in a state of facing each other in the left-right direction B. Further, the pressure cylinder 52 and the pair of upper and lower links 531 are disposed at symmetrical positions in the depth direction D with respect to the central portion of the movable mold 32. The pressure cylinder 52 and the pair of upper and lower links 531 are arranged in four locations around the horizontal center portion of the movable mold 32.

As shown in FIG. 3, the pressurizing cylinder 52 is directed to the side, the cylinder main body is attached to the rotation connecting portion 532 of the pair of upper and lower links 531, and the rod end portions of the piston rod are in the left-right direction B. Are attached so as to face each other.
When the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D are lowered, the piston rod of the pressure cylinder 52 is stroked and the link 531 of the toggle mechanism 53 is rotated as the movable mold 32 is lowered. Thereafter, when the movable mold 32 and the driven mold are overlapped with the fixed mold 31 to pressurize each workpiece, the pump 42 is driven to supply the hydraulic oil O to the head side port of the pressurizing cylinder 52. And the lifting cylinder 51 pressurize each workpiece.

  When the movable mold 32 and the driven molds 33 </ b> A and 33 </ b> B are moved up and down, the hydraulic oil O is supplied from the pump 42 to the lift cylinder 51 to operate the lift cylinder 51. On the other hand, when the movable mold 32 and the driven molds 33A to 33D overlap the fixed mold 31, and when pressing each workpiece, the elevating cylinder 51 is operated and the hydraulic oil is supplied from the pump 42 to the pressure cylinder 52. O is supplied and the pressure cylinder 52 is operated.

4 and 5 are diagrams schematically showing a hydraulic circuit in the press device 1. FIG. FIG. 4 shows the flow of the hydraulic oil O when the press device 1 moves from the original position 101 to the processing position 102 and the movable mold 32 and the driven molds 33A to 33D are lowered to press the workpiece. . FIG. 5 shows the flow of the hydraulic oil O when the press apparatus 1 returns from the processing position 102 to the original position 101 and the movable mold 32 and the driven molds 33A to 33D are raised to their original positions. In each figure, the lifting cylinder 51 and the pressurizing cylinder 52 are described with the number of arrangements omitted to two.
As shown in FIG. 4, the press device 1 uses a plurality of pumps 42, and when operating the elevating cylinder 51, only one of the pumps 42 can be operated, and the elevating cylinder 51 and pressurization are operated. When the cylinder 52 is operated, the entire pump 42 can be operated. The plurality of pumps 42 is not limited to two, and three or more pumps 42 can be connected in parallel.

As shown in FIGS. 4 and 5, the operations of the plurality of elevating cylinders 51 and the pressurizing cylinders 52 are performed by solenoid valves that are operated by signals sent from the control device of the press device 1.
As the solenoid valve of this example, a lowering valve 61 used when lowering the movable mold 32 and the driven molds 33A to 33D, a lifting valve 62 used when raising the movable mold 32 and the driven molds 33A to 33D, There is a pressurizing valve 63 used when pressurizing each workpiece.
Normally, the hydraulic oil O can flow only in the forward direction to the head side port and the rod side port connected to the bypass pipe 513 in each elevating cylinder 51, and the hydraulic oil O can also flow in the reverse direction by a pilot operation. Pilot check valves 514 and 515 are provided.

  Each of the pilot check valves 514 and 515 has a forward direction in which the hydraulic oil O flows into the head side port or the rod side port of the elevating cylinder 51. The press device 1 prevents the hydraulic oil O from flowing out of the lifting cylinder 51 when the supply of the hydraulic oil O to the lifting cylinder 51 is stopped by using the pilot check valves 514, 515. The movable mold 32 and the driven molds 33A to 33D are configured to be stopped at predetermined positions.

  As shown in FIGS. 4 and 5, each rod side pipe 512 connected to a plurality of lifting cylinders 51 has a flow rate that equalizes the flow rate of the hydraulic oil O flowing out from each lifting cylinder 51 to each rod side pipe 512. A balance mechanism 64 is provided. Although details are omitted, the flow rate balance mechanism 64 is configured by using a plurality of differential pressure valves. By restricting the flow rate of the hydraulic oil O on the side returning to the tank 41 by using the flow rate balance mechanism 64, when the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D descend, in particular, the lift cylinders 51 from the bypass pipe 513. The flow rate of the hydraulic oil O flowing into the head side port can be made uniform. Thereby, when using the several raising / lowering cylinder 51 to which the bypass piping 513 is applied, it can prevent applying the eccentric load with respect to the movable mold | type 32 from the several raising / lowering cylinder 51. FIG. Then, the movable mold 32 and the driven molds 33A to 33D can be lowered vertically while maintaining the horizontal balance with respect to the fixed mold 31.

  In the rod side pipe 512 of each lifting / lowering cylinder 51, when the movable die 32 and the driven dies 33A to 33D are lowered, the flow rate adjustment is performed to adjust the flow rate of the hydraulic oil O flowing out from each lifting / lowering cylinder 51 to each rod side piping 512. A mechanism 65 is provided. The flow rate adjusting mechanism 65 is configured by a flow rate adjusting valve 651 that pilot-operates with a signal from the control device and limits the flow rate of the hydraulic oil O flowing through the rod side pipe 512 to a predetermined flow rate. The flow rate adjustment mechanism 65 of this example uses a plurality (two in this example) of flow rate adjustment valves 651 with different flow rate restriction amounts, and the flow rate adjustment valve 651 changes the flow rate of the hydraulic oil O by a switching operation from the control device. Depending on whether or not the valve 651 is passed, the stroke speed of the piston rod 516 in each elevating cylinder 51 can be varied.

Thereby, the descent speeds of the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D that are lowered using the hydraulic oil O flowing down the bypass pipe 513 can be appropriately adjusted. Specifically, in the initial and middle stages of the lowering of the movable mold 32 and the driven molds 33A to 33D, the flow rate adjustment mechanism 65 is made smaller in flow rate so that the lowering speed of the movable mold 32 and the driven molds 33A to 33D is increased. In the later stage of the lowering of the movable mold 32 and the driven molds 33A to 33D, the flow rate adjustment mechanism 65 can increase the flow rate restriction to slow down the moving mold 32 and the driven molds 33A to 33D.
Further, by adjusting the flow rate adjusting mechanism 65, it is possible to prevent the lowering speed of the movable mold 32 and the driven molds 33A to 33D from becoming too fast due to the hydraulic oil O flowing out from the tank 41 to the bypass pipe 513. .

Next, the operation of the press apparatus 1 of this example will be described with reference to FIGS. 4 and 5.
As shown in FIG. 4, when lowering the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D, the pump 42 is driven, the lowering valve 61 is operated, and the hydraulic oil by the pump 42 is supplied to the head side port of each lifting cylinder 51. O is supplied. At this time, pilot operation of the pilot check valve 515 connected to the rod side port of each lifting / lowering cylinder 51 is performed by the pilot pressure from the lowering valve 61. As a result, a state is formed in which the hydraulic oil O existing in the rod-side space in the cylinder main body 517 of each elevating cylinder 51 passes in the reverse direction of each pilot check valve 515.
Then, the hydraulic oil O existing in the rod-side space in the cylinder body 517 of each lifting cylinder 51 flows through each rod-side pipe 512, passes through the flow rate balance mechanism 64 and the flow rate adjustment mechanism 65, and passes through the check valve. Then, it is supplied to the head side port of each elevating cylinder 51 or recovered to the tank 41.

Further, by forming a state in which the piston rod 516 can be lowered in each lifting cylinder 51, the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D are lowered using the gravity W applied thereto, The hydraulic oil O flows from the tank 41 through the bypass pipe 513 to the head side port (see FIG. 1).
Thus, the piston rod 516 in each elevating cylinder 51 moves from the head side of the cylinder main body 517 to the rod side by the hydraulic oil O flowing from the bypass pipe 513 and the hydraulic oil O sent from the pump 42. . As a result, the movable mold 32 and the driven molds 33A to 33D can be quickly lowered.

When the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D pressurize each workpiece, the pump 42 is driven, the pressurizing valve 63 is operated, and the hydraulic oil by the pump 42 is supplied to the rod side port of each pressurizing cylinder 52. O is supplied. At this time, the hydraulic oil O present at the head side port of each pressure cylinder 52 is collected into the tank 41 through the pipe 523.
And the pressurizing force by each raising / lowering cylinder 51 and the pressurizing force using each pressurizing cylinder 52 and the toggle mechanism 53 can be made to act on the movable mold | type 32, and the big pressurization force required for the shaping | molding of a workpiece | work is movable. It can act on the mold 32.

  On the other hand, as shown in FIG. 5, when the movable mold 32 and the driven molds 33 </ b> A to 33 </ b> D are lifted, the lift valve 62 is operated while the pump 42 is being driven. The hydraulic oil O from the pump 42 is supplied to the rod-side port of each elevating cylinder 51. At this time, pilot operation of the pilot check valve 514 connected to the head side port of each lifting / lowering cylinder 51 is performed by the pilot pressure from the ascending valve 62. As a result, a state is formed in which the hydraulic oil O existing in the space on the head side in the cylinder main body 517 of each elevating cylinder 51 passes in the opposite direction of each pilot check valve 514. Then, the hydraulic oil O present in the space on the head side in the cylinder main body 517 of each elevating cylinder 51 is collected into the tank 41.

Further, pilot operation of the pilot check valve 522 connected in the middle of the pipe 521 connected to the rod side port of each pressurizing cylinder 52 is performed by the pilot pressure from the ascending valve 62. As a result, a state is formed in which the hydraulic oil O existing in the rod-side space in the cylinder body of each pressurizing cylinder 52 passes in the reverse direction of the pilot check valve 522. Then, the hydraulic oil O present in the rod-side space in the cylinder main body portion of each pressure cylinder 52 is collected into the tank 41.
In this way, the movable die 32 and the driven dies 33A to 33D can be raised using the elevating cylinders 51, and the press device 1 can be returned to the original position 101.

Next, the effect by the press apparatus 1 of this example is demonstrated.
The press device 1 of this example is devised to increase the descending speed of the movable die 32 by providing a bypass pipe 513 in the head side port of the plurality of lifting cylinders 51.
Specifically, the bypass pipe 513 is provided so as to connect the head side port of the elevating cylinder 51 and the tank 41. The bypass pipe 513 can cause the hydraulic oil O in the tank 41 to flow out to the head side port of the elevating cylinder 51 without passing through the pump 42.

When pressing the workpiece by the press device 1, the hydraulic oil O is returned from the rod side port of the elevating cylinder 51 to the tank 41, and the pump from the tank 41 is supplied to the head side port of the elevating cylinder 51. The hydraulic oil O discharged by 42 and the hydraulic oil O flowing out from the tank 41 via the bypass pipe 513 flow in.
Accordingly, the piston rod 516 in the elevating cylinder 51 is quickly lowered using the gravity W acting on the movable mold 32 and the driven molds 33A to 33D, and the movable mold 32 and the driven molds 33A to 33D are moved toward the fixed mold 31. Can be quickly lowered. Moreover, the descent speed of the movable mold | type 32 can be improved by the device on the very simple apparatus which provided the bypass piping 513. FIG.

  The press device 1 of this example constitutes a multi-stage press device 1. When the moving strokes of the movable mold 32 and the driven dies 33 </ b> A to 33 </ b> D are long like the multi-stage press apparatus 1, a bypass pipe 513 is provided and movable. By using the gravity W acting on the die 32 and the driven dies 33A to 33D, the tact (cycle time) required for the press working of the workpiece can be shortened more effectively.

In the press device 1 of the present example, the bypass pipe 513 is provided to actively use the gravity W acting on the movable mold 32 and the driven molds 33A to 33D, thereby reducing the discharge capacity of the pump 42. Can do. And the electric motor used for the pump 42 can be reduced in size.
Further, by reducing the load applied to the pump 42, the hydraulic oil O can be made difficult to be heated, and the absolute amount of the hydraulic oil O required for cooling to a predetermined temperature in the tank 41 is reduced. The capacity of the tank 41 can be reduced.

  Therefore, according to the press apparatus 1, the descent speed of the movable mold 32 and the driven molds 33A to 33D can be improved by an extremely simple device, and the tact required for the press work can be shortened.

DESCRIPTION OF SYMBOLS 1 Press apparatus 21 Guide part 22 Movable base 23A, 23B Driven base 31 Fixed type 32 Movable type 33A-33D Driven type 41 Tank 42 Pump 51 Lifting cylinder 513 Bypass piping 52 Pressure cylinder 53 Toggle mechanism 61 Lowering valve 62 Lifting valve 63 Valve for pressurization 64 Flow rate balance mechanism 65 Flow rate adjustment mechanism O Hydraulic oil

Claims (5)

Fixed type,
A movable mold that is guided in the vertical direction by the guide section and moves up and down with respect to the fixed mold;
An elevating cylinder for elevating the movable mold;
A pump that sends hydraulic oil to the lift cylinder to operate the lift cylinder;
A tank connected to the pump and storing the hydraulic fluid,
A bypass pipe is connected to the head side port of the elevating cylinder to let the hydraulic oil in the tank flow out without going through the pump.
The press cylinder according to claim 1, wherein the elevating cylinder is configured to receive the movable dead weight and to cause the piston rod to stroke downward by hydraulic oil flowing from the bypass pipe. In the press device according to claim 1, a driven die that is pushed by the movable die and descends toward the fixed die is disposed between the fixed die and the movable die.
The press cylinder characterized in that the elevating cylinder is configured to continuously lower the movable mold and the driven mold by hydraulic oil flowing in from the bypass pipe and hydraulic oil sent from the pump. apparatus. 3. The press device according to claim 1, wherein the rod side pipe includes a flow rate adjusting mechanism that adjusts a flow rate of hydraulic oil flowing out from the lift cylinder to the rod side pipe when the movable mold is lowered. Provided,
A press apparatus characterized in that the movable type descending speed is adjusted by the flow rate adjusting mechanism. The press apparatus according to any one of claims 1 to 3, wherein a plurality of the elevating cylinders are arranged in alignment with the movable mold,
Each rod side pipe connected to the plurality of lifting cylinders is provided with a flow rate balance mechanism that equalizes the flow rate of hydraulic oil flowing out from each lifting cylinder to each rod side pipe,
A press apparatus characterized in that the flow rate of the hydraulic oil flowing into the head side port of each of the lift cylinders is made uniform when the movable mold is lowered by the flow rate balance mechanism. The press apparatus according to any one of claims 1 to 4, wherein the press apparatus includes a pressurizing cylinder that applies pressure to the movable mold that overlaps the fixed mold, in addition to the lift cylinder. ,
The press device according to claim 1, wherein the pump is configured to send hydraulic oil to the pressurizing cylinder.

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