JP4813422B2 - Cylinder device and knockout device in forging press - Google Patents

Description

  The present invention relates to a cylinder device and a knockout device in a forging press.

Conventionally, a mechanism for operating a knockout pin using a cam fixed to an eccentric shaft has been employed in a knockout device in a press. Such a mechanism has an advantage that a large knockout force can be generated because the cam and the knockout pin are mechanically connected and the rotational force of the eccentric shaft is used as the driving force of the knockout pin.
However, since the cam mechanism is employed, it is necessary to replace the cam in order to change the knockout timing and the like, and it is very difficult to change the timing and the like. In addition, in order to knock out at an optimal timing according to the forging material to be forged, it is necessary to prepare a cam for each workpiece, which is economically problematic.

  As a device for solving the problems of the knockout device using such a cam mechanism, a knockout device employing a hydraulic cylinder or a servo motor has been developed (for example, Patent Documents 1 and 2).

Patent Document 1 discloses a knockout device that operates a knockout pin by a hydraulic cylinder.
As shown in FIG. 3, in such a device, the knockout block 122 connected to the knockout pin 123 is connected to the hydraulic cylinder 120 via the knockout lever 121. Therefore, if the hydraulic cylinder 120 is expanded and contracted, the knockout pin 123 is extended. Can be moved up and down.
Since the knockout pin 123 is operated by the hydraulic cylinder 120, the knockout timing and the like can be freely changed to some extent by controlling the amount of oil supplied to the hydraulic cylinder 120 using a hydraulic device such as a servo valve. be able to.

Patent Document 2 discloses a knockout device that operates a knockout pin using a ball screw mechanism operated by a servomotor.
As shown in FIG. 4, in this apparatus, a ball screw 131 is connected to the main shaft of the servo motor 130, and one end of the drive arm 133 is connected to a nut holder 132 screwed into the ball screw 131. Since the other end of the drive arm 133 is connected to the knockout pin 134, when the servo motor 130 is operated, the nut holder 132 moves along the ball screw 131, and in conjunction with the movement of the nut holder 132, Knockout pin 134 can be raised and lowered.
Since the knockout pin 134 is operated by the movement of the nut holder 132, in other words, the knockout pin 134 is operated by the rotation of the servo motor 130, the timing of knockout can be freely changed to some extent.

By the way, in the case of a hot forging press, if the contact time between the forging material and the mold becomes long, the heat of the forging material is transmitted to the mold, and the mold softens due to the heat and the mold life is shortened. Therefore, high speed is required for the knockout operation.
On the other hand, when the speed of the knockout operation is increased, the moving speed and the moving acceleration of the knockout pin are increased, so that the knocked-out forged material jumps easily. When this jumping phenomenon occurs, the forged material lifted from the die after knockout cannot be placed at a predetermined position, and it becomes difficult to automatically convey the forged material.
Therefore, in addition to the high-speed movement of the knockout pin, the knockout device of the hot forging press is required to have a function of controlling the movement speed of the knockout pin so as not to cause a jumping phenomenon even when the high-speed knockout is performed.

In the case of a knockout device using a hydraulic cylinder, a large knockout force can be exerted at a high speed when releasing. However, because it is less responsive than the cam mechanism due to hydraulic control, it is difficult to accurately control the movement speed of the knockout pin after release, and it is difficult to prevent the jumping phenomenon when performing high-speed knockout operation. . In particular, when a large hydraulic cylinder is used to generate a large knockout force, it is more difficult to make a high-speed response.
On the other hand, since the knockout device using the ball screw mechanism operated by the servo motor has high responsiveness, the movement speed of the knockout pin after the mold release can be accurately controlled even when the high speed knockout operation is performed. However, it is difficult for the servo motor to exert a large knockout force when releasing. Certainly, if a large servo motor is used, it is possible to generate a large knockout force. However, since the apparatus becomes large and very expensive, the equipment cost increases.

JP 2000-288666 A JP-A-11-138226

  In view of the above circumstances, the present invention provides a knockout device in a forging press that can flexibly control the operation of a knockout pin and prevent an increase in the size of equipment, and a cylinder device that can be used for such a knockout device. With the goal.

A cylinder device according to a first aspect of the present invention includes a double rod cylinder that is actuated by a working fluid, and a pressing mechanism that can move one rod of the two rod cylinders from the axial direction thereof. A pressing member that is not fixed to the rod and can push the end of the one rod toward the other rod, and the pressing member is advanced and retracted along the axial direction of the one rod by a screw nut mechanism. It is characterized by comprising moving means.
The cylinder device according to a second aspect is the cylinder device according to the first aspect, wherein the screw nut mechanism of the moving means is configured such that when the pistons of the rod cylinders are moved toward the other rod side by the working fluid, the pressing member is It is controlled to move while in contact with the end of the rod.
The cylinder device according to a third aspect of the present invention is the cylinder device according to the first or second aspect, wherein the rod cylinders have a communication passage that communicates a pair of fluid chambers sandwiching the piston, and a space between the pair of fluid chambers provided in the communication passage. A circuit having a switching valve for switching communication between the two rod cylinders is connected, the pressure receiving area on the one rod side is smaller than the pressure receiving area on the other rod side It is characterized by that.
A knockout device in a forging press according to a fourth aspect of the present invention is provided in a forging press that molds a forging material with a pair of upper and lower molds, and a knockout pin whose upper end is provided so as to be able to protrude and retract from the bottom surface of the lower mold, and the knockout pin A knockout device comprising an elevating mechanism for elevating and lowering the shaft along the axial direction thereof, wherein the elevating mechanism has the cylinder device according to claim 1, 2, or 3, wherein the other rod of both rod cylinders in the cylinder device is provided. When the amount of protrusion increases, the knockout pin is configured to protrude from the bottom surface of the lower mold.

According to the first invention, when both rod cylinders are operated by the working fluid, a large output can be supplied to the outside from the other rod. Further, if one rod is pushed toward the other rod by the pushing member of the pushing mechanism, the movement of the other rod can be adjusted accurately and flexibly even if the output is small. That is, if a drive source for driving both rod cylinders is selected, the other rod can be moved in an optimum state in accordance with the situation of use. Since the pressing member is not fixed to one rod, it is possible to prevent a large load from being applied to the pressing member when the drive mechanism is switched or when both rod cylinders are moved by the working fluid. Can do.
According to the second invention, since the pressing member is always in contact with the end of one of the rods, it is possible to prevent a time lag from occurring in the movement of the rod when switching from driving by the working fluid to driving by the screw nut mechanism.
According to the third aspect of the present invention, if the fluid chamber on one rod side and the fluid chamber on the other rod side communicate with each other by the switching valve, the piston moves toward the one rod side according to the difference in pressure receiving area. Force (hereinafter referred to as differential pressure) is generated. For this reason, since it can be set as the state which pressed one rod against the press member, when a rod moves by a press mechanism, a rod can be moved with the same movement speed and the same movement acceleration as a press member. Further, if the movement of the pressing member is fixed, the rod is pressed against the pressing member by the differential pressure, so that the movement of the piston can be fixed. Furthermore, if the pressing member is retracted away from one rod, the other rod moves toward the pressing member due to the differential pressure, so that the protruding amount of the other rod also decreases. That is, it is not necessary to provide a special circuit for reducing the amount of protrusion of the other rod, so that the circuit can be configured simply. Since a differential pressure is applied to the piston, it is possible to prevent a time lag from occurring in the movement of the pressing member and the movement of the rod.
According to the fourth aspect of the invention, if the piston is actuated by the working fluid at the initial motion of the knockout pin, a large knockout force can be generated, so that the forging material can be reliably released. On the other hand, after the forging material is released, if one rod is pushed toward the other rod by the pushing member of the pushing mechanism, the protrusion amount of the knockout pin can be increased by the movement of the pushing member. In addition, since the movement of the pressing member is controlled by the screw nut mechanism, the movement speed and movement acceleration of the knockout pin can be finely adjusted. Therefore, the forging material can be surely released from the mold, and the forging material can be prevented from jumping, so that the posture of the forging material at the stroke end can be kept stable. Since the pressing member is not fixed to one rod, it is possible to prevent a large load from being applied to the pressing member when the drive mechanism is switched or when both rod cylinders are moved by the working fluid. Can do.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic explanatory diagram of the cylinder device 10. As shown in the figure, the cylinder device 10 pushes both rod cylinders 11 operated by a working fluid and one rod 14 of both rod cylinders 11 toward the other rod 13 (downward in FIG. 1). And a pressing mechanism 20 that can be moved. That is, the cylinder device 10 is configured to be operated by the working fluid and the pressing mechanism 20.

  In the following, for convenience, one rod 14 is referred to as an upper rod 14, the other rod 13 is referred to as a lower rod 13, one rod 14 side in both rod cylinders 11 is upward, and the other rod 13 side is referred to. This will be described as lower.

First, the double rod cylinder 11 and the circuit 30 for controlling the supply and discharge of the working fluid to and from the double rod cylinder 11 will be described.
As shown in FIG. 1, both rod cylinders 11 include a cylinder body 12 having a piston 12p therein. Rods 13 and 14 are erected on the upper and lower surfaces of the piston 12 p in the cylinder body 12, and the tips of the rods 13 and 14 protrude from the cylinder body 12.
Since the upper rod 14 has a larger shaft diameter than the lower rod 13, the area under which the piston 12p of both rod cylinders 11 receives the pressure of the working fluid (hereinafter referred to as the pressure receiving area) is The pressure receiving area on the rod 14 side is smaller than the pressure receiving area on the lower rod 13 side.

As shown in FIG. 1, fluid chambers 12 a and 12 b (hereinafter simply referred to as an upper fluid chamber 12 a and a lower fluid chamber 12 b) separated by a piston 12 p in a cylinder body 12 of both rod cylinders 11 communicate with a circuit 30. Has been.
The circuit 30 includes a pipe 31p that communicates the upper fluid chamber 12a of the cylinder body 12 and the working fluid supply means 31. The working fluid supply means 31 supplies a working fluid such as working oil adjusted to a predetermined pressure to both rod cylinders 11, and for example, a pump or the like can be used. The pipe 31p is provided with a check valve in order to prevent the working fluid from flowing from the upper fluid chamber 12a toward the working fluid supply means 31.
The circuit 30 is provided with a pipe 32p that communicates the lower fluid chamber 12b of the cylinder body 12 and the tank 32. The pipe 32p is a switch for switching the communication cutoff between the tank 32 and the lower fluid chamber 12b. A valve 33 is interposed.
The circuit 30 also includes a communication pipe 35p that connects the pipe 31p and the pipe 32p, and a switching valve 35 for switching communication between the pipe 31p and the pipe 32p is interposed in the pipe 35p. Yes.

  Since both the rod cylinders 11 and the circuit 30 have the above-described configuration, both the pipes 31p and 32p are shut off by the switching valve 35, and between the lower fluid chamber 12b and the tank 32 by the switching valve 33. If communicating, the piston 12p can be moved downward by supplying the working fluid of a predetermined pressure from the working fluid supply means 31 to the upper fluid chamber 12a. Then, since the lower rod 13 moves downward together with the piston 12p, the protruding amount of the lower rod 13 from the cylinder body 12 can be increased.

  On the other hand, if the piston 12p is allowed to move upward, in that state, the switching valve 33 blocks the lower fluid chamber 12b and the tank 32, and the switching valve 35 communicates between both pipes 31p and 32p. The piston 12p can be moved upward. Then, since the lower rod 13 moves upward together with the piston 12p, the protruding amount of the lower rod 13 from the cylinder body 12 can be reduced.

The reason why the piston 12p can be moved upward simply by communicating between the pipes 31p and 32p is as follows.
If the switching valve 33 shuts off the lower fluid chamber 12b and the tank 32 and the switching valve 35 communicates between the pipes 31p and 32p, the pressure of the working fluid in the upper fluid chamber 12a and the lower fluid in both rod cylinders 11 will be described. The pressure of the working fluid in the chamber 12b can be the same pressure. Then, since the pressure receiving area on the upper rod 14 side of the piston 12p is smaller than the pressure receiving area on the lower rod 13 side, even if the pressure of the working fluid in both the spaces 12a and 12b is the same, the pressure receiving area Depending on the difference, an upward force (hereinafter referred to as differential pressure) is generated in the piston 12p. Since the working fluid can freely flow between the upper fluid chamber 12a and the lower fluid chamber 12b, when a differential pressure is applied to the piston 12p, the working fluid moves from the upper fluid chamber 12a to the lower fluid chamber 12b. The piston 12p moves upward.

Next, the pressing mechanism 20 will be described.
As shown in FIG. 1, a servo motor 21 is provided above the rod 14 above the both rod cylinders 11. The servo motor 21 is disposed such that its main shaft faces the upper rod 14 and the main shaft and the upper rod 14 are coaxial, and is fixed to the cylinder body 12 of both rod cylinders 11 via a stay 21a. Has been.

The base end of the screw shaft 23 is connected to the main shaft of the servo motor 21 via a speed reducer 22a and a coupling 22b. The screw shaft 23 is disposed so as to be coaxial with the main shaft of the servo motor 21, that is, coaxial with the upper rod 14.
The tip end portion of the screw shaft 23 is inserted into a shaft insertion space 14 h formed in the upper rod 14. This shaft insertion space 14h is formed along the axial direction from the upper end surface of the upper rod 14, and even if the piston 12p is moved upward by the working fluid, the tip of the screw shaft 23 does not contact the inner bottom surface. It is formed to a depth of.
In the screw shaft 23, a nut member 24 is screwed into a portion between the upper end surface of the upper rod 14 and the coupling 22b.

  For this reason, if the servomotor 21 is operated to rotate the screw shaft 23, the nut member 24 moves up and down along the screw shaft 23. Therefore, if the nut member 24 is moved downward, that is, toward the upper rod 14 of both rod cylinders 11, the nut member 24 can be brought into contact with the upper end surface of the upper rod 14, so that the upper rod 14 is moved. It can be pushed and moved from the axial direction, and the amount of protrusion of the lower rod 13 from the cylinder body 12 can be increased.

The cylinder device 10 having the above configuration has the following operational effects.
First, the cylinder device 10 can operate both rod cylinders 11 with the working fluid supplied via the circuit 30 and the pressing mechanism 20, but if both rod cylinders 11 are operated with the working fluid, A large output can be supplied to the outside from the rod 13. On the other hand, if both rod cylinders 11 are operated by the pressing mechanism 20, the movement of the other rod can be adjusted accurately and flexibly even if the output is small.
In other words, the cylinder device 10 can move the lower rod 13 in an optimum state according to the situation of use by selecting a drive source for driving both rod cylinders 11.

Further, when both rod cylinders 11 are operated by the working fluid, the servo motor 21 is controlled so as to move in a state where the lower surface of the nut member 24 is in contact with the upper end surface of the upper rod 14.
For this reason, when the driving source that supplies the driving force to both rod cylinders 11 is switched from the working fluid to the servo motor 21 of the pressing mechanism 20, a time lag occurs in the movement of the lower rod 13, that is, the movement of the knockout pin 2. Can be prevented.

By the way, if the nut member 24 and the upper rod 14 are moved in a state where they are always in contact with each other, they can be fixed. However, when both are fixed, due to a shock or the like when the drive mechanism is switched. The screw shaft 23 and the nut member 24 may be damaged.
This is because it is practically difficult to completely match the moving speed and moving acceleration of the nut member 24 set in the servo motor 21 with the moving speed and moving acceleration of the upper rod 14 by the working fluid. Then, when the drive mechanism is switched from the working fluid drive to the pressing mechanism 20, the moving speed of the upper rod 14 due to the working fluid is higher than the moving speed of the nut member 24 set in the servo motor 21. Further, a force for separating the upper rod 14 and the nut member 24 is applied to the portion where the upper rod 14 and the nut member 24 are fixed, the fixing portion is damaged, and the nut member 24 and the screw shaft 23 may be damaged. There is sex.
However, in the cylinder device 10 of the present embodiment, the nut member 24 of the pressing mechanism 20 is separate from the upper rod 14 and can be moved closer to and away from the upper rod 14, in other words, the nut member 24 is the upper rod 14. 14 is not fixed. Then, when the drive mechanism is switched, no force is applied to the nut member 24 even if the moving speed or the like of the upper rod 14 by the working fluid is faster than the moving speed or the like of the nut member 24 set in the servo motor 21. Therefore, it is possible to prevent the nut member 24, the screw shaft 23, and the like from being damaged by a shock or the like when the drive mechanism is switched.

Further, when the rod cylinders 11 are driven by the pressing mechanism 20, the upper end surface of the upper rod 14 is pressed against the nut member 24 by the differential pressure if the pressure of the working fluid in both the spaces 12 a and 12 b is set to the same pressure. It will be in the state.
Then, the nut member 24 and the upper rod 14 can be moved at the same moving speed and moving acceleration. If the movement of the nut member 24 is fixed, the movement of the piston 12p can be fixed.

If the nut member 24 is retracted away from the upper rod 14, the lower rod 13 can be moved toward the nut member 24 by the differential pressure, and the protruding amount of the lower rod 13 is also reduced. Can be made. That is, since a special circuit for reducing the protruding amount of the lower rod 13 is not required, the circuit 30 can be configured simply.
Moreover, since differential pressure is applied to the piston 12p, when the nut member 24 moves away from the upper rod 14, the upper rod 14 moves so as to follow the nut member 24. Therefore, when the nut member 24 is separated from the upper rod 14, it is possible to prevent a time lag from occurring between the timing at which the nut member 24 moves and the timing at which both rod cylinders 11 are operated.

  The nut member 24 is a pressing member referred to in the claims. In addition, the servo motor 21, the speed reducer 22a, the coupling 22b, and the screw shaft 23 constitute moving means referred to in the claims.

The main shaft and the screw shaft 23 of the servo motor 21 may be configured so that the upper rod 14 can be pushed and moved along the axial direction by the nut member 24, and is not necessarily coaxial with the upper rod 14. It is not necessary to arrange so that.
Furthermore, the device for rotating the screw shaft 23 is not limited to the servo motor, and a stepping motor, an inverter motor, or the like may be used as long as the rotation amount and the rotation speed of the screw shaft 23 can be accurately controlled.

  Next, a knockout device 1 for a forging press that employs the above-described cylinder device 10 as a drive source for a lifting mechanism that lifts and lowers the knockout pin 2 will be described.

  FIG. 2 is a schematic explanatory view of the knockout device 1 employing the cylinder device 10. In the same figure, the code | symbol B has shown the bed of the forge press, and the code | symbol M has shown the lower metal mold | die provided in the upper surface of the bed B. FIG. The bed B and the lower mold M are formed with a through hole h penetrating in the vertical direction, and the upper end portion of the knockout pin 2 is disposed in the through hole h so as to be movable up and down.

  A swing arm 3 is provided below the knockout pin 2. The swing arm 3 is disposed so that the lower end of the knockout pin 2 is placed on the upper surface of the tip portion, and the base end portion is fixed to the shaft 4.

On the other hand, as shown in FIG. 2, the cylinder device 10 described above is provided on the side of the bed B. The cylinder device 10 is arranged such that its axial direction is in the vertical direction, that is, parallel to the raising / lowering direction of the knockout pin 2, and the tip of the lower rod 13 protrudes from the lower end thereof.
The tip of the lower rod 13 is connected to the tip of the connecting arm 5, and the base end of the connecting arm 5 is fixed to the shaft 4.

  Since it is the above structure, if the cylinder apparatus 10 is operated and the protrusion amount of the lower rod 13 is changed, the front-end | tip of the connection arm 5 can be moved up and down. Then, since the shaft 4 to which the base end of the connecting arm 5 is fixed rotates around its central axis, the swing arm 3 swings as the shaft 4 rotates, and the distal end of the swing arm 3 moves up and down. To do. Then, the knockout pin 2 placed on the upper surface of the tip of the swing arm 3 moves up and down in accordance with the vertical movement of the tip of the swing arm 3, so that the tip of the knockout pin 2 is caused to appear and disappear from the lower mold M. The forging material on the lower mold M can be knocked out.

The swing arm 3, the shaft 4, the connecting arm 5, and the cylinder device 10 are the lifting mechanism of the knockout device 1 described in the claims, but the configuration for connecting the knockout pin 2 and the cylinder device 10 is particularly special. The knockout pin 2 may be configured to move up and down when the amount of protrusion of the lower rod 13 in the cylinder device 10 increases or decreases.
If the knockout pin 2 is configured to move up and down when the amount of protrusion of the rod 13 in FIG. 1 increases or decreases in the cylinder device 10, the orientation of the rod 13, that is, the arrangement of the cylinder device 10 is particularly good. It is not limited.

Next, the knockout operation by the knockout device 1 of the present embodiment will be described.
For the sake of simplicity, the communication between the lower fluid chamber 12b and the tank 32 by the switching valve 33 is referred to as turning on the switching valve 33, and the switching valve 33 is turned off to block between the two. That's it. Similarly, communication between the pipes 31p and 32p by the switching valve 35 is referred to as turning on the switching valve 35, and disconnecting between the two is referred to as turning off the switching valve 35.

First, at the start of knockout, that is, when high speed, short stroke and high load are required, the switching valve 33 is turned on and the switching valve 35 is turned off. The fluid is supplied into the upper fluid chamber 12a of the rod cylinder 11. Then, the lower rod 13 moves downward in accordance with the pressure / flow rate of the working fluid and the amount of protrusion increases, so that the knockout pin 2 rises at a predetermined knockout load and a predetermined knockout speed, and the forging material is The mold is released from the lower mold M.
At this time, since the driving force of both the rod cylinders 11 (the driving force of the knockout pin 2) is supplied from the working fluid, the output obtained from the lower rod 13 is increased. Then, since the knockout force of the knockout pin 2 can be increased, the forging material can be reliably separated from the lower mold M.
When both rod cylinders 11 are operated by the working fluid, the servo motor 21 of the pressing mechanism 20 operates so that the lower surface of the nut member 24 always moves in contact with the upper end surface of the upper rod 14. Is controlled.

  When the forging material is released from the lower mold M, the switching valves 33 and 35 are switched, the switching valve 33 is turned off and the switching valve 35 is turned on, and the lower fluid chamber 12b is communicated with the upper fluid chamber 12a. It becomes a state. When the moving speed of the nut member 24 downward is increased in this state, the piston 12p is moved downward together with the upper rod 14 by the force applied from the nut member 24, and the lower rod 13 is moved. That is, the driving force of both the rod cylinders 11 (the driving force of the knockout pin 2) is supplied from the pressing mechanism 20.

  Since the nut member 24 is moved downward so that the lower surface thereof is always in contact with the upper end surface of the upper rod 14, the drive source for supplying the knockout pin 2 with a driving force is supplied from the working fluid to the servo motor of the pressing mechanism 20. When switched to 21, there is no time lag in the movement of the lower rod 13, that is, the movement of the knockout pin 2.

When the nut member 24 is moved downward by the servo motor 21, the upward differential pressure is applied to the piston 12p of both rod cylinders 11, and the upper end surface of the upper rod 14 is in contact with the nut member 24. Move with. That is, the piston 12p and the lower rod 13 of both rod cylinders 11 descend at the same moving speed and moving acceleration as the nut member 24.
Since the moving speed and moving acceleration of the knockout pin 2 change at a constant rate with respect to the moving speed and moving acceleration of the lower rod 13 according to the ratio of the length of the swing arm 3 and the length of the connecting arm 5, If the movement speed and movement acceleration of the nut member 24 are finely adjusted, the movement speed and movement acceleration of the knockout pin 2 can also be finely adjusted.
Therefore, if both rod cylinders 11 are driven by the pressing mechanism 20, the forging material can be raised by the knockout pin 2 without causing jumping or the like.

  When the forging material rises to a predetermined height, the operation of the servo motor 21 is stopped and the movement of the nut member 24 is stopped. Then, the upper end surface of the upper rod 14 is pressed against the nut member 24 by the differential pressure, so that the movement of the piston 12p and the lower rod 13 is stopped and the movement is fixed. Moreover, since the movement of the piston 12p is fixed by the differential pressure, the movement of the knockout pin 2 is also fixed, and the forging material can be held stably at a predetermined height.

  And if a forge raw material is conveyed from the knockout pin 2, the servomotor 21 will reversely rotate and the nut member 24 will be moved upwards. At this time, since an upward differential pressure is applied to the pistons 12p of both rod cylinders 11, the upper end surface of the upper rod 14 moves so as to follow the nut member 24, and the protruding amount thereof decreases. Then, since the piston 12p and the lower rod 13 are raised, the knockout pin 2 is lowered and the knockout operation is completed.

As described above, in the knockout device 1 of the present embodiment, the piston 12p is actuated by the working fluid when the knockout pin 2 is initially moved, so that the forging material can be released from the mold.
On the other hand, since the knockout pin 2 is operated by the pressing mechanism 20 after the forging material is released, the knockout pin 2 can be moved at a high speed, and the forging material can be quickly moved away from the mold. Therefore, it is possible to prevent the adverse effect caused by the long contact time between the forging material and the mold.
Moreover, when the knockout pin 2 is operated by the pressing mechanism 20, the circuit 30 is controlled so that an upward differential pressure is applied to the pistons 12 p of both rod cylinders 11. Then, the moving speed and moving acceleration of the nut member 24 of the pressing mechanism 20 and the moving speed and moving acceleration of the lower rod 13 can be made the same, so that the moving speed and moving acceleration of the knockout pin 2 can be finely adjusted. it can. Therefore, jumping of the forging material can be prevented, and the posture of the forging material at the stroke end of the knockout pin 2 can be kept stable.

Further, when the nut member 24 is raised while the upward differential pressure is applied to the piston 12p, the piston 12p can be raised by the differential pressure, and the knockout pin 2 can also be lowered. That is, it is not necessary to provide a special circuit for raising the piston 12p, in other words, for lowering the knockout pin 2, so that the circuit 30 can be configured simply.
Moreover, since differential pressure is applied to the piston 12p, when the nut member 24 moves away from the upper rod 14, the upper rod 14 moves so as to follow the nut member 24. Therefore, it is possible to prevent a time lag from occurring between the timing at which the nut member 24 is separated from the upper rod 14 and the timing at which the knockout pin 2 is lowered.

  The accumulator 36 may be communicated with the pipe 31p of the circuit 30. In this case, it is possible to load the accumulator 36 with a part of the working fluid supplied from the working fluid supply means 31 to the rod cylinders 11 at the initial stage of knockout where high speed, short stroke and high load are required. Then, since the flow rate of the working fluid supplied to the both rod cylinders 11 by the working fluid supply means 31 can be suppressed as compared with the flow rate of the working fluid necessary for the actual knockout operation, the working fluid supply means 31 and the like are enlarged. Can be prevented.

  The cylinder device 10 described above is not limited to the press knockout device 1 as described above, and can be used in various devices. For example, it is suitable for a device that needs to be used by switching between a situation where high output is required and a situation where high-speed and high-precision rod movement is required. For example, it is suitable for a device that drives a mold in a device (for example, a closed forging device) that needs to control (for example, synchronize) a plurality of cylinders with high output and high accuracy.

The cylinder device of the present invention is suitable as a drive source when high-precision positioning is required after high-power operation or when it is necessary to control (for example, synchronize) a plurality of cylinders with high power and high accuracy. .
In addition, the knockout device in the press of the present invention is suitable as a knockout device in a press in which molding such as coining, trimming, drawing, and forging is performed by raising and lowering the upper die.

It is a schematic explanatory drawing of the cylinder apparatus 10 of this embodiment. 1 is a schematic explanatory diagram of a knockout device 1 that employs a cylinder device 10. FIG. It is a schematic explanatory drawing of the knockout apparatus which employ | adopted the hydraulic cylinder as a drive source. It is a schematic explanatory drawing of the knockout apparatus which employ | adopted the servomotor as a drive source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Knockout apparatus 2 Knockout pin 10 Cylinder apparatus 11 Both rod cylinders 13 Lower rod 14 Upper rod 20 Pressing mechanism 21 Servo motor 23 Screw shaft 24 Nut member 30 Circuit M Lower mold

Claims (4)

A double rod cylinder actuated by a working fluid;
It consists of a pressing mechanism that can move one rod of both rod cylinders by pushing from its axial direction,
The pressing mechanism is
A pressing member that is non-fixed to the one rod and can push the end of the one rod toward the other rod;
A cylinder device comprising: a moving means for moving the pressing member forward and backward along the axial direction of the one rod by a screw nut mechanism. The screw nut mechanism of the moving means is
When the rod cylinders are actuated by the working fluid so that the protruding amount of the other rod increases, the pressing member is controlled to move in contact with the end of the one rod. The cylinder device according to claim 1, wherein: In both the rod cylinders,
A circuit including a communication passage that communicates a pair of fluid chambers sandwiching the piston and a switching valve that is provided in the communication passage and switches communication between the pair of fluid chambers is connected.
The pistons of the rod cylinders are
3. The cylinder device according to claim 1, wherein a pressure receiving area on the one rod side is smaller than a pressure receiving area on the other rod side. A knockout pin that is provided in a forging press that molds a forging material with a pair of upper and lower molds, the upper end of which is provided so as to be able to protrude and retract from the bottom surface of the lower mold, and a lifting mechanism that moves the knockout pin up and down along the axial direction In a knockout device consisting of
The lifting mechanism is
4. A cylinder device according to claim 1, wherein the knockout pin projects from the bottom surface of the lower mold when the amount of projection of the other rod of both rod cylinders in the cylinder device increases. A knockout device in a forging press characterized by the above.

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