JP5471476B2 - Closure device and closure method - Google Patents

Description

  The present invention is provided in a closed forging device that closes and forges an upper mold and a lower mold that are arranged to face each other in the vertical direction and are movable in the vertical direction, and the upper mold and the lower mold are closed. The present invention relates to a technique of a closing device and a closing method for maintaining a state.

Conventionally, a closed forging method is known as a technique for forging a part (forged product) having a portion (tooth portion) protruding radially from a shaft portion, such as a bevel gear, with high accuracy. .
The closed forging method is mainly performed by a closed forging device (for example, a forging press machine). The closed forging device is disposed so as to be opposed to the vertical direction and is provided so as to be movable in the vertical direction. A pair of punches penetrating in the vertical direction in the axial direction at the mold and the lower mold, the closing device disposed below the lower mold, and the central part of the upper mold and the lower mold in plan view And so on.
Then, while lowering the upper die, the upper die and the lower die are closed by pressing the lower die upward by the closing hydraulic cylinder of the closing device, and such a closed state is maintained. A forged product is formed by forging with a pair of punches (see, for example, “Patent Document 1”).

By the way, the upper mold and the lower mold in the closed state are pressed downward by the closing hydraulic cylinder, while the upper mold is lowered against the pressing force of the closing hydraulic cylinder. These upper mold and lower mold are lowered together.
That is, after the upper mold and the lower mold are closed, the hydraulic oil supplied to the hydraulic cylinder for closing is on the side of the hydraulic pump that discharges the hydraulic oil by the thrust (pressing force) related to the lowering of the upper mold. The force to push back into the work will work.
Accordingly, the pressure of the hydraulic oil rises, and if such a state is left, eventually the hydraulic oil will flow backward to the hydraulic pump, or the hydraulic piping path will be damaged, causing a failure of the entire closure device.

Therefore, in general, in the hydraulic piping path provided in the closing device, hydraulic oil is provided in the middle of the hydraulic piping path (hereinafter referred to as “hydraulic oil feeding path”) that connects the closing hydraulic cylinder and the hydraulic pump. A hydraulic piping path (hereinafter referred to as a “hydraulic oil return path”) that branches into a hydraulic tank that stores oil is provided in a branched manner, and a relief valve (pressure control) as a pressure setting circuit is provided near the branch in the hydraulic oil return path. If the pressure of the hydraulic oil is equal to or higher than the set pressure of the relief valve (pressure control valve) set to a constant value, the hydraulic oil is returned to the hydraulic tank via the hydraulic oil return path.
The set pressure of the relief valve (pressure control valve) is a value higher than the discharge pressure of the hydraulic pump, that is, the closed state of the upper die and the lower die, which is determined from experience in forging a forged product. The pressure value required for maintaining was preset.

  On the other hand, the production cycle (a series of steps from putting the material into the closed forging device to taking out the forged product from the closed forging device) when closing the forged product with the closed forging device is several seconds per cycle. It is often performed in a short time, and the lowering speed of the upper mold is often performed at such a high speed that the time from the start of lowering the upper mold to the arrival at the bottom dead center is within approximately one second.

  Therefore, in the conventional closing device, when the upper mold and the lower mold are closed, the upper mold that is lowered collides with the lower mold at a high speed, and the pressure of the hydraulic oil in the closing hydraulic cylinder increases rapidly. However, the pressure release operation of the relief valve cannot follow, and a large surge pressure (abnormal pressure fluctuation in which the pressure suddenly increases due to the operation delay of the relief valve (pressure control valve)) has occurred.

Here, the pressure fluctuation of the hydraulic oil supplied to the closing hydraulic cylinder will be described more specifically with reference to FIG.
FIG. 4 is a diagram showing the relationship between the clogging pressure and the ram angle over the production cycle per one cycle in the conventional clogging device, and the solid line in this figure shows the pressure fluctuation related to the actual hydraulic oil, A two-dot chain line indicates a pressure fluctuation related to a set pressure of the relief valve (pressure control valve).

“Occlusion pressure” means the pressure applied to the lower die upward to maintain the upper and lower die occlusion states. In the description in this specification, the hydraulic cylinder of the occlusion device is used. It is synonymous with the pressure of the hydraulic fluid supplied to.
The “ram angle” indicates a position in the vertical direction with respect to the upper mold.
That is, the press slide plate on which the upper die is fixed is connected to a crank mechanism that is rotationally driven by a drive motor through a connection mechanism, and the crank shaft of the crank mechanism rotates once, so that the press slide plate One cycle related to the up-and-down movement is completed.
Therefore, in FIG. 4, the rotation angle of the crankshaft is expressed as a “ram angle”, and the current position of the upper mold is expressed by the value of the “ram angle”.
That is, when the “ram angle” is 0 °, the upper die is at the highest position, and when the “ram angle” is 180 °, the upper die is lowered to the lowest (lower) Further, when the “ram angle” is in a state of 360 °, the upper die is lifted from the lowest position and indicates the highest position again.

As shown in FIG. 4, when the upper mold descends from the position where the ram angle is 0 ° (the upper mold is the uppermost position), the upper mold collides with the lower mold at the position where the ram angle is X1 °. These upper mold and lower mold are closed.
Further, when the upper die is further lowered, the upper die and the lower die are integrally lowered while maintaining the closed state, and the ram angle is 180 ° (the upper die is the lowest position). Thus, the lowering of the upper mold and the lower mold ends.

Thereafter, when the upper mold starts to rise, the upper mold and the lower mold are lifted together while maintaining the closed state, and at the position where the ram angle is Y1 °, the position of the lower mold in the vertical direction is While being held, only the upper mold is raised, and the closed state of these upper mold and lower mold is released.
Then, the upper die further rises, and when the ram angle reaches 360 °, the upper die again becomes the highest position, and the movement per cycle in the upper die is completed.

On the other hand, for example, when looking at the fluctuation of the closing pressure in a state where the set pressure of the relief valve (pressure control valve) is set to a1 MPa in the vicinity of 30 MPa in advance, if the ram angle exceeds the position where X1 ° is exceeded, The clogging pressure suddenly increases due to the collision between the lower mold and the lower mold, temporarily reaches a2MPa near 45MPa, which greatly exceeds the set pressure a1MPa of the relief valve, and then rapidly decreases and shows a value near a1MPa. .
That is, at the moment when the ram angle exceeds the position where the angle is X1 °, a surge pressure (Z1 region shown in FIG. 4) is temporarily generated in the closing pressure, and the relief valve (pressure control valve) with the passage of time thereafter. Is alleviated, the hydraulic oil is returned to the hydraulic tank via the hydraulic oil return path, and the closing pressure drops to around a1 MPa, which is the set pressure of the relief valve (pressure control valve).

In addition, a1MPa which is the set pressure value (set pressure value) of the relief valve (pressure control valve) is to maintain the closed state between the upper mold and the lower mold, which is determined from experience when the forged product is closed and forged. This is the value of the occlusion pressure required for.
Therefore, the set pressure value of the relief valve (pressure control valve) is a value determined for each forged product to be closed forged.

  Once the occlusion pressure has dropped to around a1 MPa, which is the set pressure value of the relief valve (pressure control valve), the occlusion pressure will no longer greatly exceed a1 MPa, even if the upper mold is lowered, and a value around 30 MPa. (Z2 area shown in FIG. 4) is held.

  When the ram angle exceeds a position where the ram angle becomes 180 ° (the upper die is at the lowest position), the upper die starts to rise again, so that the closing pressure also drops rapidly from around a1 MPa, and the ram angle becomes Y1 °. After the upper and lower molds are closed in the position, the closing pressure becomes a value of a3 MPa which is the discharge pressure of the hydraulic pump.

Thus, in the conventional closing device, a large surge pressure is suddenly generated as the closing pressure, so that the structure such as the closing hydraulic cylinder and the hydraulic piping path is strong against the surge pressure. It had to be strong enough to withstand.
Further, in addition to the closing device having such a configuration, the closing forging device itself needs to have a strong configuration, and the entire facility has a large configuration, resulting in an increase in equipment cost.

As a means for solving such problems, a technique disclosed in “Patent Document 2” is disclosed.
That is, in “Patent Document 2”, regarding a proportional flow rate control valve that controls the flow rate of hydraulic fluid that flows out from a hydraulic cylinder that supports a cushion pad, a die cushion pressure command that is previously commanded by a command device, and a slide speed detection. Based on the slide speed signal input from the device, the controller calculates the opening of the proportional flow control valve and controls the opening of the proportional flow control valve to an appropriate opening based on the calculation result. Techniques to do this are disclosed.

No. 7-39468 Japanese Patent Application Laid-Open No. 2006-142121

  By using the technique shown in the above-mentioned “Patent Document 2”, in the hydraulic oil supplied to the closing hydraulic cylinder, the surge pressure generated at the moment when the upper mold and the lower mold are closed is reduced, and the closing device is simplified. As a result, it seems that the equipment cost can be reduced as a whole of the closed forging device.

However, the technique disclosed in the above-mentioned “Patent Document 2” is a technique related to a die cushion device, and is practically difficult to use in a closing device provided in a closed forging device (forging press machine) that performs closed forging. is there.
That is, the technique disclosed in the above-mentioned “Patent Document 2” is a technique that is used for stamping molding with a relatively large margin in terms of time per cycle related to a production cycle such as fine blanking.
Therefore, as described above, in closed forging performed in a short time of several seconds per cycle of the production cycle, even if the opening of the proportional flow control valve is adjusted based on the calculation result by the controller, the surge pressure is generated. In time, it is practically difficult to reduce the surge pressure.

  The present invention has been made in view of the above-described current problems, and reduces the surge pressure generated at the moment when the upper mold and the lower mold are closed in the hydraulic oil supplied to the closing hydraulic cylinder. It is an object of the present invention to provide a closing device and a closing method capable of simplifying the closing device and thus reducing the equipment cost as the entire closing forging device.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the first aspect of the present invention, the upper mold and the lower mold are provided so as to be opposed to each other in the vertical direction and movable in the vertical direction, and the upper mold and the lower mold are closed and forged. A closing device provided in a closed forging device, which is provided below the lower die, and that closes the upper die and the lower die by pressing the lower die upward, thereby closing the hydraulic cylinder A hydraulic tank that stores hydraulic oil in the hydraulic cylinder, a hydraulic pump that discharges the hydraulic oil from the hydraulic tank, and a hydraulic oil supply that supplies the hydraulic oil discharged by the hydraulic pump to the hydraulic cylinder And a hydraulic oil return path that branches off from the hydraulic oil supply path and returns the hydraulic oil to the hydraulic tank, and a pressure setting circuit in the middle of the hydraulic oil return path Provided, when the pressure of the hydraulic oil supplied into the hydraulic oil supply path exceeds a set pressure in the pressure setting circuit, the hydraulic oil is returned to the hydraulic tank via the hydraulic oil return path, The set pressure in the pressure setting circuit is set to a low pressure until the timing at which the upper mold and the lower mold are closed, and is higher than the low pressure after the upper mold and the lower mold are closed. It can be switched.

  In Claim 2, it has the upper mold | type and lower mold | type which are arrange | positioned facing the up-down direction, and each provided so that a movement in the up-down direction was possible, and closed forging which closes and forges these upper mold | types and lower mold | types A closing method of the device, wherein the closing device of the closed forging device is provided below the lower die and holds the closed state of the upper die and the lower die by pressing the lower die upward. A hydraulic cylinder for closing, a hydraulic tank for storing hydraulic oil in the hydraulic cylinder, a hydraulic pump for discharging the hydraulic oil from the hydraulic tank, and the hydraulic oil discharged by the hydraulic pump to the hydraulic cylinder A hydraulic oil feed path for feeding, and a hydraulic oil feed path that branches off from the hydraulic oil feed path and feeds the hydraulic oil back to the hydraulic tank; In When a pressure setting circuit is provided, and the pressure of the hydraulic oil supplied into the hydraulic oil supply path exceeds a set pressure in the pressure setting circuit, the hydraulic oil is supplied to the hydraulic tank via the hydraulic oil return path. The set pressure in the pressure setting circuit is set to a low pressure until the upper mold and the lower mold are closed, and compared with the low pressure after the upper mold and the lower mold are closed. Can be switched to high pressure.

As effects of the present invention, the following effects can be obtained.
That is, according to the present invention, in the hydraulic oil supplied to the closing hydraulic cylinder, the surge pressure generated at the moment when the upper mold and the lower mold are closed is reduced, the closing device is simplified, and the closing forging device. It is possible to provide a closing device and a closing method capable of reducing the equipment cost as a whole.

1 is a hydraulic circuit diagram showing an overall configuration of a closing device according to an embodiment of the present invention. It is the figure which showed a series of operation | movement of the obstruction | occlusion apparatus, and is the flowchart which showed from the setting of the obstruction | occlusion setting pressure to low pressure until a press slide (upper mold | type) raises. The diagram which showed the relationship between the closure pressure and ram angle over the production cycle per cycle in the closure apparatus which concerns on one Example of this invention. The diagram which showed the relationship between the obstruction | occlusion pressure over the production cycle per cycle, and a ram angle in the conventional obstruction | occlusion apparatus.

  Next, embodiments of the invention will be described.

[Overall Configuration of Closure Device 1]
First, the whole structure of the obstruction | occlusion apparatus 1 which concerns on this invention is demonstrated using FIG.
In the following description, for convenience, the vertical direction on the drawing will be described below as the vertical direction of the closing hydraulic cylinder 2 provided in the closing device 1.

The closing device 1 is provided in the closed forging device 100 and is a device for maintaining the closed state of the upper die 51 and the lower die 52 that the closed forging device 100 has.
The closing device 1 mainly includes a closing hydraulic cylinder 2 and a hydraulic circuit 3 for operating the closing hydraulic cylinder 2.
On the other hand, in addition to the closing device 1, the closed forging device 100 includes a bed 54 serving as a base, a press slide plate 55 disposed above the bed 54 and movable in the vertical direction, and an upper and lower sides above the bed 54. The upper mold 51 and the lower mold 52 are arranged to face each other.
Under the lower mold 52, the closing hydraulic cylinder 2 is built in the bed 54 so as to press the lower mold 52 upward, and the upper mold 51 is fixed to the lower surface of the press slide plate 55. Thus, the upper mold 51 and the lower mold 52 are provided so as to be movable in the vertical direction.

First, the configuration of the closing hydraulic cylinder 2 will be described.
The closing hydraulic cylinder 2 includes a cylinder tube 21, a knockout pin 23, a plurality of pistons 22, 22, 22, cushion pins 24, 24, and the like.

  The cylinder tube 21 is a part serving as a base portion of the closing hydraulic cylinder 2, and includes a body member 21A made of a hollow member, and an upper lid member 21B and a lower lid member 21C that close both upper and lower ends of the body member 21A. The

The body member 21 </ b> A is made of a substantially cylindrical member, and is disposed in the bed 54 of the closed forging device 100 with the axial direction facing the up and down direction.
A plurality of projecting portions 21a, 21a, and 21a projecting inward in the direction orthogonal to the axial direction from the inner peripheral surface of the body member 21A are formed on the inner peripheral portion that is the internal space of the body member 21A. .
More specifically, the protrusions 21a are each formed in a disk shape having a through hole 21b in the center. In the body member 21A, the plurality of projecting portions 21a, 21a, and 21a are arranged coaxially with the body member 21A, and are arranged in parallel along the axial direction with a certain interval. The body member 21A is integrally formed.

  In addition, the inner diameter dimension (A dimension in FIG. 1) regarding the inner peripheral part of the body member 21A is formed to be approximately the same as the outer dimension of the enlarged diameter part 22b of the piston 22 described later, and a plurality of protrusions 21a, 21a, The inner diameter dimensions (B dimensions in FIG. 1) of the through holes 21b, 21b, and 21b of 21a are formed to be approximately the same as the outer dimensions of the main body portion 22a of the piston 22, respectively.

A hydraulic path 21c is formed in the body member 21A.
The hydraulic path 21c extends upward from the lower end portion of the body member 21A, and is formed by bending the extending direction toward the inner peripheral side of the body member 21A in the vicinity of the upper end portion of the body member 21A.

  A plurality of branch paths 21d and 21d are provided in the middle of the hydraulic path 21c, and the branch paths 21d and 21d respectively extend from the branch section with the hydraulic path 21c toward the inner peripheral side of the body member 21A. Formed.

The extension end of the hydraulic path 21c is located above the inner periphery of the plurality of protrusions 21a, 21a, 21a formed on the inner periphery of the body member 21A. Communicated with the department.
The extending ends of the branch paths 21d and 21d are respectively between the uppermost protrusion 21a and the intermediate protrusion 21a and between the intermediate protrusion 21a and the lowermost protrusion 21a. It communicates with the inner periphery.

The upper lid member 21B is a disk-shaped member, and is disposed coaxially with the trunk member 21A at the upper end of the trunk member 21A.
The upper lid member 21B is detachably fixed to the body member 21A via a fastening member (not shown) such as a bolt.

  A first through hole 21e is formed in the central portion of the upper lid member 21B in a plan view with the axial direction directed vertically, and a plurality of second through holes 21f and 21f are formed around the first through hole 21e. It is formed in parallel with the axial direction of the first through hole 21e.

  The first through hole 21e and the second through holes 21f and 21f are respectively provided with a knockout pin 23 and cushion pins 24 and 24, which will be described later, and these knockout pin 23 and cushion pins 24 and 24, respectively. Is slidably disposed along the axial direction through the first through hole 21e and the second through holes 21f and 21f.

The lower lid member 21C is a disk-shaped member, and is disposed coaxially with the trunk member 21A at the lower end of the trunk member 21A.
The lower lid member 21C is detachably fixed to the body member 21A via a fastening member (not shown) such as a bolt.

A third through hole 21g is formed in the central portion of the lower lid member 21C in plan view with the axial center direction directed vertically, and a pipe path 21h is formed around the third through hole 21g. It is formed in parallel with the axial center direction of 21 g.
The inner diameter of the third through hole 21g is formed to be approximately the same as the inner diameter of the first through hole 21e formed in the upper lid member 21B.

And since the piping path 21h is formed in the position corresponding to the formation position of the hydraulic path 21c of the trunk member 21A in the lower lid member 21C, the lower lid member 21C is fixed to the lower end portion of the trunk member 21A. Thus, the upper end portion of the piping path 21h communicates with the lower end portion of the hydraulic path 21c formed in the body member 21A.
Further, the upper lid member 21B is coaxially fixed at the upper end portion of the body member 21A, and the lower lid member 21C is coaxially fixed at the lower end portion of the body member 21A, thereby forming the lower lid member 21C. The third through hole 21g and the first through hole 21e formed in the upper lid member 21B are arranged coaxially.

The piston 22 is a member for transmitting the pressure of hydraulic oil fed to the inner peripheral portion of the cylinder tube 21 to cushion pins 24 and 24 described later.
The piston 22 includes a cylindrical main body portion 22a serving as a base, and a disk-shaped diameter-enlarged portion provided at one end of the main body portion 22a and having a larger cross-sectional shape than the axial cross section of the main body portion 22a. The main body portion 22a and the enlarged diameter portion 22b are arranged coaxially with each other and are integrally formed.

  A through hole 22c penetrating along the axial direction is formed in the central portion of the piston 22 in a plan view. The inner diameter of the through hole 22c is the first formed on the upper lid member 21B and the lower lid member 21C, respectively. -It is formed to the same extent as the inner diameter of the third through holes 21e, 21g.

  The plurality of pistons 22, 22, and 22 are provided in the inner peripheral portion of the body member 21 </ b> A in a state in which the enlarged-diameter portions 22 b, 22 b, and 22 b are directed upward while being coaxially arranged in the axial direction. Is done. Further, the pistons 22, 22, 22 incorporated in the inner peripheral part of the body member 21 </ b> A have a plurality of projecting parts 21 a, 21 a, 21 a, whose main body parts 22 a, 22 a, 22 a are formed on the inner peripheral part of the body member 21 </ b> A. The through holes 21b, 21b and 21b are respectively inserted.

That is, each piston 22 is inserted through the main body portion 22a so as to be slidable along the axial direction of the inner peripheral portion of the through hole 21b of the protruding portion 21a.
In addition, a space portion 25 surrounded by a lower surface of the enlarged diameter portion 22b, an outer peripheral surface of the main body portion 22a, an upper surface of the protruding portion 21a, and an inner peripheral surface of the body member 21A is provided below the enlarged diameter portion 22b. When the hydraulic oil flows into the space 25, the lower surface of the enlarged diameter portion 22b is pressed upward, and each piston 22 slides upward.

  The through holes 22c, 22c, and 22c of the plurality of pistons 22, 22, and 22 are coaxial with the first and third through holes 21g and 21e formed in the upper lid member 21B and the lower lid member 21C, respectively. The knockout pin 23 described later is inserted coaxially with the cylinder tube 21 in the through holes 21e, 21g, 22c, 22c, and 22c.

The knockout pin 23 is a member for discharging (knocking out) a cast product fixed to the lower die 52 of the closed forging device 100 after completion of the closed forging.
The knockout pin 23 is formed of a rod-like member, and as described above, the knockout pin 23 is inserted in the inner peripheral portion of the cylinder tube 21 with the axial direction facing the vertical direction and is slidable along the axial direction. Established.

  The lower end portion of the knockout pin 23 is connected to an actuator (not shown) composed of a ram type hydraulic cylinder mechanism or the like, and the knockout pin 23 is slid along the vertical direction (axial direction of the knockout pin 23) by the actuator. The

  On the other hand, the upper end portion of the knockout pin 23 is connected to the lower end portion of the counter punch 53 that is made of a round bar member and is disposed with the axial center direction directed in the vertical direction. The punch 53 is slid in the vertical direction.

  The upper end portion of the counter punch 53 is inserted into the lower die 52 through a through hole 52a formed along the vertical direction in the central portion of the lower die 52 of the closed forging device 100 in plan view. As the knockout pin 23 slides, the upper end portion of the counter punch 53 slides on the inner peripheral portion of the through hole 52a.

  That is, the forged product immediately after the closed forging by the closed forging device 100 is completed (before the forged product is taken out from the closed forging device 100) is in a state of being fixed to the lower die 52 and sliding upward of the knockout pin 23. When the counter punch 53 is slid upward in conjunction with the above, the forged product is pushed upward by the upper end portion of the counter punch 53 and discharged (knocked out) from the lower die 52.

The cushion pin 24 is a part for actually holding the closed state of the upper mold 51 and the lower mold 52 during closed forging by pushing the lower mold 52 upward from below.
The cushion pins 24, 24,... Are made of a round bar member, and a plurality of cushion pins 24, 24,.

That is, the cushion pins 24, 24,... Are arranged at a certain interval along the circumference centering on the knockout pin 23 provided in the center portion in plan view in the upper part of the cylinder tube 21. And arranged in parallel with the knockout pin 23.
(In addition, since FIG. 1 is the figure which showed the cross section of the obstruction | occlusion apparatus 1, only two cushion pins 24 are described.)

  Each cushion pin 24 is inserted into the second through hole 21f of the upper lid member 21B from the upper side to the lower side, and the lower end portion thereof is the outermost piston among the plurality of pistons 22, 22, and 22 housed in the body member 21A. It is connected to the upper surface of the piston 22 provided at the upper level.

  On the other hand, the upper end portion of each cushion pin 24 is connected to a pressure receiving member 26 made of a plate-like member, and each cushion pin 24 is detachably fixed to the lower surface of the lower mold 52 via the pressure receiving member 26. The

  Then, the piston 22 provided at the uppermost position in the cylinder tube 21 is slid upward by the hydraulic oil flowing into the space 25, so that the plurality of cushion pins 24, 24. Are slid upward along the inner peripheral portions of the through holes 21f, 21f,..., And the lower mold 52 is pressed upward via the pressure receiving member.

Next, the configuration of the hydraulic circuit 3 will be described.
The hydraulic circuit 3 mainly includes a hydraulic tank 33 that stores hydraulic oil circulating in the hydraulic circuit 3, a hydraulic oil supply circuit 31 that supplies hydraulic oil to the closing hydraulic cylinder 2, and a closing hydraulic cylinder 2. A hydraulic oil return circuit 32 that returns the hydraulic oil pushed back to the hydraulic tank 33 is configured.

The hydraulic oil supply circuit 31 includes a hydraulic pump 34, a hydraulic oil supply path 35, and the like.
The hydraulic pump 34 is a device for pressurizing and discharging the hydraulic oil stored in the hydraulic tank 33 to a preset pressure (discharge pressure), and is constituted by, for example, a variable pressure type piston type hydraulic pump. .

  The hydraulic oil supply path 35 is formed by a first main flow path 35a, a first branch path 35b, a plurality of second branch paths 35c, 35c, and 35c.

  The first main flow path 35a communicates with the lower end portion of the piping path 21h formed in the lower lid member 21C of the closing hydraulic cylinder 2 at one end, and the discharge port (see FIG. (Not shown).

  The first branch path 35b is branched from a branch point 36 in the vicinity of the hydraulic pump 34 in the first main stream path 35a, and a junction 44 in the middle of the first main stream path 35a in the vicinity of the closing hydraulic cylinder 2. And then merge again.

  In the first main flow path 35 a and the first branch path 35 b, check valves 37 and 37 are provided in the vicinity of the downstream side of the branch point 36 (on the closing cylinder side), even from the closing hydraulic cylinder 2. Even if the hydraulic oil is pushed back, the check valves 37 and 37 prevent the hydraulic oil from flowing back to the hydraulic pump 34.

  The plurality of second branch paths 35c, 35c, and 35c branch in parallel from the middle portion of the first main flow path 35a, more specifically, from the downstream side (the closing cylinder side) of the junction 44. The pressure sensors 38 and 38 and the stop valve are formed in order from the upstream side (hydraulic pump side) to the downstream side (closing cylinder side) at the end portions of the second branch paths 35c, 35c, and 35c. 39 and the like are connected to each other.

  The pressure sensors 38 and 38 can sequentially monitor the pressure fluctuations of the hydraulic oil supplied to the closing hydraulic cylinder 2 and the stop valve 39 can be used in the hydraulic circuit 3 for maintenance, for example. It is possible to quickly discharge the hydraulic oil circulating through the hydraulic circuit 3 to the outside.

The hydraulic oil return circuit 32 includes logic valves 40, 40, and 40, a proportional electromagnetic control valve 41, and a hydraulic oil return path 42 that constitute a pressure setting circuit.
The logic valve 40 is a so-called known logic valve that is provided so as to be slidable within the main body and includes a valve body that is urged by the urging force of a spring, and flows into the hydraulic oil return circuit 32. It is for switching the flow direction of hydraulic oil.

  That is, a proportional electromagnetic control valve 41 is connected to the logic valve 40, and the pressure of the hydraulic fluid that opens the logic valve 40 is preset by the proportional electromagnetic control valve 41, and is pushed back from the closing hydraulic cylinder 2. Even if the hydraulic fluid is about to flow into the hydraulic tank 33 via the hydraulic oil return path 42, the hydraulic fluid is temporarily blocked by the logic valve 40 until the set pressure is reached. Yes.

  Then, once the pressure of the hydraulic oil that has been dammed gradually increases and becomes equal to or higher than the set pressure, the logic valve 40 is opened, and the hydraulic oil passes through the hydraulic oil return path 42 in the hydraulic tank 33. Will flow into.

The proportional electromagnetic control valve 41 is a so-called known electromagnetic control valve that controls the pressure and flow rate of the hydraulic oil in proportion to the electrical signal. In this embodiment, the proportional electromagnetic control valve 41 is connected via the hydraulic oil return path 42. The logic valve 40 is connected to the logic valve 40 to control the back pressure of the hydraulic oil flowing into the logic valve 40 (the pressure of the hydraulic oil acting in the direction of pressing the valve body against the valve seat in the logic valve 40). Set the pressure of hydraulic fluid that will be released.
That is, the proportional electromagnetic control valve 41 and the plurality of logic valves 40, 40, 40 constitute a pressure setting circuit, and the flow direction of the working oil flowing into the working oil return path 42 is controlled by the pressure setting circuit. It is.

The hydraulic oil return path 42 includes a plurality of second main flow paths 42a, 42a, and 42a composed of three systems.
The second main flow path 42a, 42a, 42a communicates with one of a plurality of ports of the logic valves 40, 40, 40 at one end, and the hydraulic oil described above at the other end. Each is communicated with a middle portion of the feeding path 35.

  That is, in the first main flow path 35a of the hydraulic oil supply path 35, a branch point 43 is provided in the vicinity of the second branch path 35c connected to the stop valve 39 (on the closing cylinder side). A branch point 45 is provided between the junction point 36 and the junction point 44, which are communication points with the one branch path 35 b, and more specifically between the check valve 37 and the junction point 44.

  The second main flow paths 42 a, 42 a, and 42 a of the hydraulic oil return path 42 are respectively communicated with the middle part of the hydraulic oil supply path 35 through the junction 44 and the two branch points 43 and 45.

On the other hand, the plurality of logic valves 40, 40, 40 communicated with the second main flow path 42 a, 42 a, 42 a are connected to a port different from the port communicated with the second main flow path 42 a, 42 a, 42 a, The third main flow paths 42d, 42d, and 42d are communicated.
The third main flow paths 42 d, 42 d, 42 d merge with each other at the end portions and are guided into the hydraulic tank 33.

A third branch path 42b is branched and provided on the downstream side (logic valve 40 side) of the middle portion of each second main flow path 42a.
That is, the third branch path 42b communicates with the second main flow path 42a at one end, and at the other end, the pilot chamber of the logic valve 40 (the side facing the valve seat in the logic valve 40). To the space part).
The plurality of third branch paths 42b, 42b, and 42b are communicated in parallel with each other via relay paths 42c and 42c in the middle.

Here, a branch point 46 is provided in the middle of one of the plurality of relay paths 42c and 42c.
Further, a junction 47 is provided in the middle of any one of the plurality of third main flow paths 42d, 42d, and 42d.
Then, both ends of the fourth branch path 42e are connected to the branch point 46 and the junction point 47, and a proportional electromagnetic control valve 41 is disposed in the middle part of the fourth branch path 42e.

In this manner, the proportional electromagnetic control valve 41 and the plurality of logic valves 40, 40, 40 are connected via the third branch paths 43b, 43b, 43b, the relay paths 42c, 42c, and the fourth branch path 42e. A pressure setting circuit is configured.
The pressure setting circuit is disposed in the middle of the hydraulic oil return path 42, that is, between the second main flow paths 42a, 42a, 42a and the third main flow paths 42d, 42d, 42d.

The hydraulic circuit 3 mainly includes a hydraulic oil supply circuit 31, a hydraulic oil return circuit 32, and the like, and the closing hydraulic cylinder 2 is operated by the hydraulic circuit 3.
That is, the hydraulic oil discharged by the hydraulic pump 34 is distributed to the two systems of the first main flow path 35a and the first branch path 35b and distributed downstream (the closing hydraulic cylinder 2 side), and the closing hydraulic cylinder. 2, that is, after being merged again at the merge point 44, it is led to the hydraulic path 21 c of the closing hydraulic cylinder 2 through the first main flow path 35 a.

  The hydraulic oil guided to the hydraulic path 21c sequentially flows into a plurality of space portions 25, 25, 25 provided in the body member 21A of the closing hydraulic cylinder 2, and sequentially raises the plurality of pistons 22, 22, 22.

When the pistons 22, 22, 22 are lifted, the plurality of cushion pins 24, 24... Are also lifted, and the lower mold 52 is pressed upward by the cushion pins 24, 24. The
When the entire space 25, 25, 25 is filled with hydraulic oil, and the pistons 22, 22, 22 come into contact with the lower surface of the upper lid member 21B and the lower surfaces of the protrusions 21a, 21a, the pistons 22, 22, 22 are lifted. Stops, and the lower mold 52 stops at the highest position.

When the closed forging by the closed forging device 100 is started, the upper die 51 is lowered.
When the upper mold 51 is lowered to the uppermost position of the lower mold 52, the upper mold 51 and the lower mold 52 are closed.

  Here, when the upper mold 51 descends against the pressing force of the cushion pins 24, 24,... That press the lower mold 52 upward while the upper mold 51 and the lower mold 52 are closed, the body member The hydraulic fluid that has flowed into the space portions 25, 25, and 25 in 21 A is subjected to pressure in a direction in which it flows backward through the hydraulic path 21 c and is pushed back to the outside of the closing hydraulic cylinder 2.

  The pressure applied to the hydraulic oil in the closing hydraulic cylinder 2 is transmitted to the second main flow path 42 a, 42 a, 42 a of the hydraulic oil return path 42 through the first main flow path 35 a of the hydraulic oil supply path 35.

The hydraulic fluid in the second main flow paths 42a, 42a, 42a to which the pressure from the closing hydraulic cylinder 2 is transmitted flows into the third main flow paths 42d, 42d, 42d via the logic valves 40, 40, 40. If the hydraulic oil pressure has not yet reached the set pressure of the logic valves 40, 40, 40 (that is, the set pressure of the proportional electromagnetic control valve 41), the logic valves 40, 40, 40 are opened. The hydraulic oil is not blocked by these logic valves 40, 40, 40.
The hydraulic oil in the second main flow paths 42a, 42a, 42a blocked by the logic valves 40, 40, 40 is gradually increased in internal pressure as the upper mold 51 descends.

On the other hand, part of the hydraulic fluid guided to the second main flow paths 42a, 42a, and 42a is guided to the third branch paths 42b, 42b, and 42b.
The hydraulic oil guided to the third branch paths 42b, 42b, 42b is guided to the fourth branch path 42e or the pilot chambers of the logic valves 40, 40, 40, respectively.

Further, if the internal pressure of the hydraulic oil in the fourth branch path 42e branched from the third branch path 42b, 42b, 42b becomes larger than the control pressure of the proportional electromagnetic control valve 41, the proportional electromagnetic control valve 41 is opened. Therefore, if the internal pressure of the hydraulic oil in the third branch path 42b, 42b, 42b and the fourth branch path 42e is larger than the control pressure of the proportional electromagnetic control valve 41, the hydraulic oil in the third branch path 42b, 42b, 42b. Is guided to the pilot chamber, and the set pressure at which the logic valves 40, 40, 40 are opened is kept constant.
Thus, in the state where the set pressure of the logic valves 40, 40, 40 is set to a predetermined pressure by the proportional electromagnetic control valve 41, the second main flow path 42a, 42a, 42a (first main flow path 35a) When the pressure of the hydraulic oil becomes larger than the set pressure of the logic valves 40, 40, 40, the logic valves 40, 40, 40 are opened, and the second main flow path 42a, 42a, 42a and the third main flow path 42d, 42d, 42d communicates.

  Therefore, when the logic valves 40, 40, 40 are opened, the hydraulic oil guided to the second main flow paths 42a, 42a, 42a flows into the hydraulic tank 33 via the third main flow paths 42d, 42d, 42d. It is.

[Operation Method of Closure Device 1]
Next, the operation | movement method of the obstruction | occlusion apparatus 1 is demonstrated using FIG.
First, before the closed forging by the closed forging device 100 is started, the set value of the closing pressure is set to a low pressure by the proportional electromagnetic control valve 41 (step S101).
That is, the pressure of the hydraulic oil that opens the logic valve 40 is set to a low pressure by the proportional electromagnetic control valve 41.

As a specific pressure value of the “low pressure”, for example, a pressure slightly exceeding the discharge pressure of the hydraulic pump 34 is selected, and in the present embodiment, it is set to around 4 MPa.
In this way, by setting the set value of the closing pressure in the vicinity of the discharge pressure of the hydraulic pump 34, for example, after the lower mold 52 has reached the uppermost position, the hydraulic oil is further fed through the first main flow path 35a. However, since no more hydraulic oil can be supplied to the closing hydraulic cylinder 2, the pressure of the hydraulic oil in the first main flow path 35a rises and the low pressure of the logic valves 40, 40, 40 is reduced. The set pressure will be exceeded.
As a result, the logic valves 40, 40, 40 are opened, and the hydraulic oil fed to the first main flow path 35a is guided to the third main flow paths 42d, 42d, 42d through the logic valves 40, 40, 40, and the hydraulic tank It will be refluxed to 33.

When the closed forging by the closed forging device 100 is started, the press slide plate 55 is activated and starts to descend from the highest position (step S102).
That is, as the press slide plate 55 descends, the upper mold 51 starts to descend.

When the press slide plate 55 descends and the position of the upper mold 51 reaches the uppermost position of the lower mold 52, the upper mold 51 collides with the lower mold 52, and the upper mold 51 and the lower mold 52 are separated from each other. Blocked.
That is, the upper mold 51 and the lower mold 52 come into contact with each other to be in a closed state, and immediately after that, the upper mold 51 is lowered against the upward pressing force against the lower mold 52 by the closing hydraulic cylinder 2. Thus, the lower mold 52 is applied with a pressing force downward from the upper mold 51, and the closing pressure rises (step S103).

Here, the closed forging device 100 according to the present embodiment is provided with first detection means for detecting the timing at which the upper die 51 and the lower die 52 are in contact with each other. Is set to a high pressure by the proportional electromagnetic control valve 41 (step S104).
That is, the pressure of the hydraulic oil that opens the logic valve 40 is switched to a high pressure by the proportional electromagnetic control valve 41.

  In addition, as a specific pressure value of the “high pressure”, a closing pressure necessary for maintaining the closed state between the upper die and the lower die, which is determined based on experience in closing the forged product, is selected. In this embodiment, it is set around 32 MPa.

  Further, as the first detecting means, for example, any one of a photoelectric sensor for detecting the position of the upper mold 51 and a pressure sensor 38 (see FIG. 1) for monitoring a change in the pressure of hydraulic oil may be used. Good.

After the upper mold 51 and the lower mold 52 are in the closed state, the upper mold 51 and the lower mold 52 are integrated with the lowering of the upper mold 51 while the set value of the closing pressure is kept high. Descend.
That is, the set value of the closing pressure is maintained at a high pressure until the position of the upper die 51 (press slide plate 55) reaches the lowest position (bottom dead center) (step S105).

Here, the closed forging device 100 in the present embodiment is provided with second detection means for detecting the timing when the position of the upper die 51 (press slide plate 55) reaches the lowest position (bottom dead center). The set value of the blocking pressure is switched again to the low pressure by the proportional electromagnetic control valve 41 by the electric signal from the second detection means.
That is, the pressure of the hydraulic oil at which the logic valve 40 is opened is again switched to a low pressure by the proportional electromagnetic control valve 41.

  As the second detection means, for example, any one of a photoelectric sensor that detects the position of the upper mold 51 (or the lower mold 52), an encoder that detects the rotation angle of the crankshaft connected to the press slide plate 55, and the like. It may be a thing.

After the position of the upper die 51 (press slide plate 55) reaches the lowest position (bottom dead center), the upper die 51 (press slide plate 55) starts to rise again.
When the upper die 51 (press slide plate 55) starts to rise, the lower die 52 pressed upward by the closing hydraulic cylinder 2 also starts to rise, and the upper die 51 and the lower die 52 are closed. Ascending as a whole while maintaining the state.

As a result, the downward pressing force applied to the lower mold 52 by the upper mold 51 gradually decreases, and the closing pressure decreases.
That is, as the upper die 51 (press slide plate 55) is raised, the closing pressure is lowered (step S106).

  Then, when the upper mold 51 (press slide plate 55) rises and the position of the upper mold 51 reaches the uppermost position of the lower mold 52, the lower mold 52 remains at the uppermost position, and these upper molds 51 remain. The closed state of the lower mold 52 is released.

  After the closed state of the upper mold 51 and the lower mold 52 is released, only the upper mold 51 (press slide plate 55) is raised. Then, the upper die 51 becomes the uppermost position again, and the closed forging by the closed forging device 100 per cycle is completed.

Thus, FIG. 3 shows the pressure fluctuation of the hydraulic oil supplied to the closing hydraulic cylinder 2 when the closing forging device 100 performs the closing forging while switching the set value of the closing pressure between the high pressure and the low pressure. It explains using.
FIG. 3 is a diagram showing the relationship between the closing pressure and the ram angle over one production cycle in the closing device 1 of the present embodiment, and the solid line in this drawing indicates the pressure fluctuation related to the actual hydraulic oil. The two-dot chain line indicates the pressure fluctuation related to the actual set pressure of the logic valve 40 switched by the proportional electromagnetic control valve 41.

As described above, the “closure pressure” means a pressure applied to the lower mold 52 upward in order to maintain the closed state of the upper mold 51 and the lower mold 52. Is synonymous with the pressure of hydraulic fluid supplied to the closing hydraulic cylinder 2.
Further, the “ram angle” indicates a position in the vertical direction with respect to the upper mold 51.

  As shown in FIG. 3, when the upper mold 51 is lowered from the position where the ram angle is 0 ° (the upper mold 51 is the uppermost position), the upper mold 51 is connected to the lower mold 52 at a position where the ram angle is X2 °. By colliding, the upper mold 51 and the lower mold 52 are closed.

  Further, when the upper die 51 is further lowered, the upper die 51 and the lower die 52 are integrally lowered while maintaining the closed state, and the position where the ram angle becomes 180 ° (the upper die 51 is at the lowest position). ), The lowering of the upper mold 51 and the lower mold 52 is finished.

  After that, when the upper mold 51 starts to rise, the upper mold 51 and the lower mold 52 are lifted together while maintaining the closed state, and at the position where the ram angle becomes Y2 °, The position in the direction is held and only the upper mold 51 is raised, and the closed state of the upper mold 51 and the lower mold 52 is released.

  Then, the upper die 51 is further raised, and when the ram angle reaches 360 °, the upper die 51 becomes the uppermost position again, and the movement of the upper die 51 per cycle is completed.

On the other hand, in this embodiment, the set pressure of the hydraulic oil at which the logic valve 40 is opened is set to a low pressure by the proportional electromagnetic control valve 41 in advance until the timing at which the upper mold 51 and the lower mold 52 collide with each other. After the 51 and the lower mold 52 collide, the low pressure is switched to the high pressure.
As described above, as the specific pressure value of the “low pressure”, for example, a closing pressure slightly exceeding the discharge pressure of the hydraulic pump 34, that is, around 4 MPa is selected, and the specific pressure value of the “high pressure” is selected. As the pressure value, a closing pressure necessary for maintaining the closed state of the upper die and the lower die, that is, the vicinity of 32 MPa, which is determined from experience when closing the forged product is selected.

  Looking at the fluctuation of the closing pressure when switching the set pressure, the closing pressure suddenly increases due to the collision between the upper mold 51 and the lower mold 52 immediately after the position where the ram angle becomes X2 °. Begins to rise.

On the other hand, the control of the proportional electromagnetic control valve 41 for controlling the set pressure of the logic valve 40 is immediately switched from the low pressure to the high pressure when the ram angle reaches X2 °, and the actual set pressure (curved curve of the two-dot chain line) ) Starts to rise rapidly so as to follow the increase in the occlusion pressure (solid curve) immediately after the position where the ram angle exceeds X2 °.
That is, when the position of the ram angle reaches X2 °, the control signal for switching the set pressure to the proportional electromagnetic control valve 41 is issued, and thereafter, the actual operation of the proportional electromagnetic control valve 41 is slightly delayed. As the operation and the pressure of the hydraulic oil led to the pilot chambers of the logic valves 40, 40, and 40 increase, the actual switching from the low pressure to the high pressure of the set pressure of the logic valve 40 is performed.

  As a result, the closing pressure suddenly increases due to the collision between the upper mold 51 and the lower mold 52, and a surge pressure (Z4 region shown in FIG. 3) is generated. Due to the operation to turn up, that is, the switching operation of the proportional electromagnetic control valve 41 from the low pressure to the high pressure, the operation of the proportional electromagnetic control valve 41 and the logic valve 40 is somewhat delayed particularly when the set pressure is switched from the low pressure to the high pressure. Occurrence of the surge pressure is mitigated, and the rising end thereof is suppressed to approximately 35 MPa.

  The blockage pressure (solid curve) that has once reached the rising end is then returned to the hydraulic tank 33 via the hydraulic oil return path 42, so that the set pressure (two-dot chain curve) is reached. It drops rapidly to around 32 MPa.

  After the occlusion pressure (solid curve) once drops to about 32 MPa, which is the set pressure (two-dot chain curve), the occlusion pressure (solid curve) is no longer set even if the upper mold 51 is lowered. It does not greatly exceed the curve of the two-dot chain line), and the vicinity of 30 MPa (Z5 region shown in FIG. 3) is retained.

Thereafter, when the ram angle exceeds a position where the ram angle becomes 180 ° (the upper mold 51 is at the lowest position), the upper mold 51 starts to rise again, so that the occlusion pressure (solid curve) also drops rapidly from around 30 MPa.
Then, after the closed state of the upper mold 51 and the lower mold 52 is released at the position where the ram angle is Y2 °, the closed pressure (solid curve) is the discharge pressure of the hydraulic pump 34 (see FIG. 1). The value is around 4 MPa.

  On the other hand, the control of the proportional electromagnetic control valve 41 that controls the set pressure of the logic valve 40 is switched from high pressure to low pressure when the ram angle reaches 180 °, and the actual set pressure (curved line indicated by a two-dot chain line). Is just after the position where the ram angle exceeds 180 °, and in the same manner as in the case of the above-mentioned ascent, there is a slight delay in operation related to the proportional electromagnetic control valve 41 and the logic valve 40 (range Z6 shown in FIG. 3), etc. In this way, it begins to fall rapidly so as to follow the fall of the occlusion pressure (solid curve).

  Before the ram angle reaches Y2 °, the set pressure of the logic valve 40 by the proportional electromagnetic control valve 41 is set to a low pressure, and then the movement per cycle in the upper mold 51 is completed. Up to this point, the set pressure is kept at a low pressure.

  As described above, the closing device 1 according to the present embodiment has the upper mold 51 and the lower mold 52 that are disposed so as to face each other in the vertical direction and are movable in the vertical direction. And a closing device 1 provided in a closed forging device 100 that closes and forges the lower die 52, and is provided below the lower die 52, and presses the lower die 52 upward so that these upper dies are pressed. 51, the closing hydraulic cylinder 2 for holding the closed state of the lower mold 52, the hydraulic tank 33 for storing the hydraulic oil in the closing hydraulic cylinder 2, and the hydraulic pressure for discharging the hydraulic oil from the hydraulic tank 33 A pump 34, a hydraulic oil supply path 35 that supplies the hydraulic oil discharged by the hydraulic pump 34 to the closing hydraulic cylinder 2, and a branch from the hydraulic oil supply path 35 are provided. And a hydraulic oil return path 42 for returning the hydraulic oil to the hydraulic tank 33. The hydraulic oil return path 42 includes logic valves 40, 40, 40, a proportional electromagnetic control valve 41, and the like in the middle of the hydraulic oil return path 42. A pressure setting circuit is provided, and when the pressure of the hydraulic oil fed into the hydraulic oil feed path 35 exceeds the set pressure of the logic valves 40, 40, 40 in the pressure setting circuit, the hydraulic oil is activated. It is returned to the hydraulic tank 33 via the oil return path 42, and the set pressure of the logic valves 40, 40, 40 in the pressure setting circuit is low until the timing when the upper mold 51 and the lower mold 52 are closed. After the upper mold 51 and the lower mold 52 are closed, the pressure is switched to a high pressure higher than the low pressure.

  Further, the closing method in the present embodiment has an upper mold 51 and a lower mold 52 that are arranged to face each other in the vertical direction and are movable in the vertical direction, and these upper mold 51 and lower mold 52 are provided. A closed forging device for closing and forging the closed forging device, the closing device of the closed forging device being provided below the lower die 52 and pressing the lower die 52 upward to A closing hydraulic cylinder 2 that holds the closed state of the mold 51 and the lower mold 52, a hydraulic tank 33 that stores hydraulic oil in the closing hydraulic cylinder 2, and a hydraulic pump 34 that discharges the hydraulic oil from the hydraulic tank 33. A hydraulic oil feed path 35 for feeding the hydraulic oil discharged by the hydraulic pump 34 to the closing hydraulic cylinder 2, and a branch from the hydraulic oil feed path 35. A hydraulic oil return path 42 for returning the hydraulic oil to the pressure tank 33, and a pressure formed by logic valves 40, 40, 40, a proportional electromagnetic control valve 41, etc. in the middle of the hydraulic oil return path 42 When a setting circuit is provided and the pressure of the hydraulic oil fed into the hydraulic oil feed path 35 exceeds the set pressure of the logic valves 40, 40, and 40 in the pressure setting circuit, the hydraulic oil is Returned to the hydraulic tank 33 via the return path 42, the set pressure of the logic valves 40, 40, 40 in the pressure setting circuit is kept low until the timing when the upper mold 51 and the lower mold 52 are closed. After the upper mold 51 and the lower mold 52 are closed, the pressure is switched to a high pressure higher than the low pressure.

  With such a configuration, according to the closing device 1 and the closing method in the present embodiment, the hydraulic oil supplied to the closing hydraulic cylinder 2 is generated at the moment when the upper mold 51 and the lower mold 52 are closed. It is possible to provide the closing device 1 and the closing method capable of reducing the surge pressure, simplifying the closing device, and thus reducing the equipment cost of the closing forging device 100 as a whole.

In other words, in this embodiment, the set pressure of the hydraulic oil at which the logic valve 40 is opened is set to a low pressure in advance by the proportional electromagnetic control valve 41, and immediately after the upper mold 51 and the lower mold 52 collide, the pressure is increased from the low pressure to the high pressure. It is supposed to be switched to.
Therefore, the blockage pressure rapidly increases due to the collision between the upper mold 51 and the lower mold 52, while the set pressure of the logic valve 40 also begins to increase rapidly so as to follow the increase in the blockage pressure (solid curve). It will be.
As a result, the closing pressure suddenly rises due to the collision between the upper die 51 and the lower die 52 and a slight surge pressure is generated, but the operation starts to increase the set pressure of the logic valve 40, that is, a proportional electromagnetic control valve. The switching operation from the low pressure to the high pressure of 41 causes a slight delay in the operation of the proportional electromagnetic control valve 41 and the logic valve 40 especially when the set pressure is switched from the low pressure to the high pressure, thereby mitigating the surge pressure rise. Therefore, the rising end is suppressed to about 35 MPa, which is very low compared to the conventional closing device (about 45 MPa).

Accordingly, since it is possible to reduce the surge pressure temporarily generated as the closing pressure, the structure such as the closing hydraulic cylinder 2 and the hydraulic piping path (the hydraulic oil supply path 35 and the hydraulic oil return path 42) are described. Therefore, simplification can be achieved.
And the simplification as the whole closure apparatus 1 can aim at reduction of an installation cost by extension as the whole closure forging apparatus 100 by extension.

DESCRIPTION OF SYMBOLS 1 Blocking device 2 Blocking hydraulic cylinder 33 Hydraulic tank 34 Hydraulic pump 35 Hydraulic fluid feed path 40 Logic valve 41 Proportional electromagnetic control valve 42 Hydraulic fluid return path 51 Upper mold 52 Lower mold 100 Blocking forging device

Claims (2)

It has an upper mold and a lower mold that are arranged to face each other in the vertical direction and are movable in the vertical direction.
A closing device provided in a closed forging device for closing and forging the upper die and the lower die,
A hydraulic cylinder for closing that is provided below the lower mold and holds the upper and lower molds closed by pressing the lower mold upward;
A hydraulic tank for storing hydraulic oil of the hydraulic cylinder;
A hydraulic pump that discharges the hydraulic oil from the hydraulic tank;
A hydraulic oil supply path for supplying the hydraulic oil discharged by the hydraulic pump to the hydraulic cylinder;
A branching from the hydraulic oil supply path, a hydraulic oil return path for returning the hydraulic oil to the hydraulic tank;
Have
A pressure setting circuit is provided in the middle of the hydraulic oil return path,
When the pressure of the hydraulic oil supplied into the hydraulic oil supply path exceeds a set pressure in the pressure setting circuit, the hydraulic oil is sent back to the hydraulic tank via the hydraulic oil return path,
The set pressure in the pressure setting circuit is set to a low pressure until the timing when the upper mold and the lower mold are closed,
After the upper mold and the lower mold are closed, the pressure is switched to a high pressure higher than the low pressure.
An occluding device characterized by that. It has an upper mold and a lower mold that are arranged to face each other in the vertical direction and are movable in the vertical direction.
A closing method of a closed forging device for closing and forging the upper mold and the lower mold,
The closing device of the closing forging device is:
A hydraulic cylinder for closing that is provided below the lower mold and holds the upper and lower molds closed by pressing the lower mold upward;
A hydraulic tank for storing hydraulic oil of the hydraulic cylinder;
A hydraulic pump that discharges the hydraulic oil from the hydraulic tank;
A hydraulic oil supply path for supplying the hydraulic oil discharged by the hydraulic pump to the hydraulic cylinder;
A branching from the hydraulic oil supply path, a hydraulic oil return path for returning the hydraulic oil to the hydraulic tank;
Have
A pressure setting circuit is provided in the middle of the hydraulic oil return path,
When the pressure of the hydraulic oil supplied into the hydraulic oil supply path exceeds a set pressure in the pressure setting circuit, the hydraulic oil is sent back to the hydraulic tank via the hydraulic oil return path,
The set pressure in the pressure setting circuit is set to a low pressure until the timing when the upper mold and the lower mold are closed,
After the upper mold and the lower mold are closed, the pressure is switched to a high pressure higher than the low pressure.
An occlusion method characterized by the above.

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