JP3722247B2 - Press die cushion equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a die cushion device for a press which can control a rising speed of a cushion pad in accordance with a die cushion capability, a press speed, and the like.
[0002]
[Prior art]
Conventionally, as this type of die cushion device, for example, one disclosed in Japanese Patent Application Laid-Open No. 4-143098 (Japanese Patent Publication No. 7-102476) is known.
[0003]
In the press die cushion device of the above publication, a first flow rate adjustment valve and a second flow rate adjustment valve are arranged in parallel in the middle of a pipe line that connects a locking valve that supplies locking oil to the locking cylinder device and an oil tank. And a first opening degree adjusting means for adjusting the opening degree of the first flow rate adjustment valve in correspondence with the detected die cushion capacity, and a second flow rate adjustment valve in correspondence with the detected SPM. Consists of a second opening adjustment means for adjusting the opening, and even if the die cushion capacity is changed to a lower one, the rise time of the die cushion can be shortened. In addition, even when the press speed (SPM) is switched to a low speed, the ascending speed can be slowed, so that the SPM can be switched without any trouble.
[0004]
[Problems to be solved by the invention]
However, the conventional press die cushion device requires two flow rate adjusting valves and first and second opening degree adjusting means for controlling these flow rate adjusting valves, so that the configuration is complicated and expensive. There was a bug.
The present invention has been made to remedy such a conventional problem, and a simple press having a structure in which the rising speed of the cushion pad can be controlled in accordance with the die cushion capacity, the pressing speed, etc. with one variable throttle valve. The object of the present invention is to provide an inexpensive cushioning device.
[0005]
[Means for solving the problems and effects]
A first aspect of the present invention is a cushion pad 2 which is elastically supported by the cushion cylinder 3, in the press of the die cushion apparatus having a locking cylinder 4 and the locking valve 8 for locking at the bottom dead center of the cushion pad 2,
The piston rod 4b of the locking cylinder 4 is connected to the cushion pad 2, the locking valve 8 opens and closes a conduit connecting the upper chamber 4 ₁ and the lower chamber 4 ₂ of the locking cylinder 4,
A variable throttle valve 9 having a configuration in which the opening degree is adjusted by moving the piston 9a in the axial direction by forward and reverse rotation of the electric motor, provided one in the pipe line;
By controlling the electric motor, characterized in that it comprises conduit by the locking valve 8 is when in the open, and control means for adjusting the flow rate of the oil flowing into the lower chamber 4 ₂ from the upper chamber 4 ₁ The die cushion device of the press.
[0006]
With the above configuration, by adjusting the degree of opening of the variable throttle valve 16 in accordance with the die cushion capability and press speed, because it adjusts the amount of oil flowing from the upper chamber 4 ₁ locking cylinder 4 in the lower chamber 4 _2, cushion pad 2 can be adjusted arbitrarily, so that when the die cushion capacity is large and the press speed is slow, the cushion pad 2 is slowed so that the cushion pad 2 has impact or vibration near the top dead center. Since it does not occur, it does not cause noise.
[0007]
The small die cushion capability Conversely, if the press speed is high, since by increasing the rising speed of the cushion pad 2 can follow the cushion pad 2 to increase the speed of the slide, productivity by shortening the cycle time Can be improved.
[0008]
Further, since the rising speed of the cushion pad 2 can be controlled by one variable throttle valve 16 , the configuration is simpler than that of the conventional two flow rate adjusting valves and an opening adjusting means for controlling them. It is easy to manufacture and can be provided at low cost.
[0009]
According to a second aspect of the present invention, in the first aspect of the present invention, an opening degree detecting means 17 for detecting the opening degree of the variable throttle valve 9 from the rotation of the electric motor is provided, and the opening degree detected by the opening degree detecting means 17 is This is a press die cushion device that is fed back to a control means for controlling an electric motor .
[0010]
With the above configuration, the drive means is feedback controlled according to the current opening detected by the opening detection means 17, so that the opening can be adjusted with high accuracy.
[0011]
A third aspect of the invention is compared in the first invention, the control means includes a degree which is at least either one more set of die cushion capability and press speed, the opening degree inputted from the opening detection means 17 to a press die cushion device formed by controlling the electric motor such that the opening degree of the variable throttle valve 9 is set opening.
[0012]
With the above configuration, just by inputting processing conditions such as die cushion capacity and press speed to the control means in advance, the opening of the variable throttle valve is automatically adjusted accordingly. Is not required at all.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a circuit diagram of a die cushion device, FIG. 2 is an enlarged cross-sectional view of a variable diaphragm, and FIG.
In FIG. 1, reference numeral 1 denotes a die cushion body, which comprises a cushion pad 2 and a cushion cylinder 3 comprising one or a plurality of air cylinders (two in the embodiment) that elastically support the cushion pad 2 from below. A locking cylinder 4 made of a hydraulic cylinder is connected to the lower part of the cylinder 3.
[0015]
The cushion cylinder 3 has a piston 3a inside, and an upper end of a piston rod 3b protruding upward from the piston 3a is connected to the cushion pad 2, and a pressure chamber 3c below the piston 3a is provided in a pressure chamber 3c. Air is supplied from the air tank 5 through the switching valve 6.
[0016]
The locking cylinder 4 provided below the cushion cylinder 3, the lower chamber 4 the upper chamber 4 ₁ and the lower chamber inside the piston 4a having a check valve 7 to allow only flow of ₂ onto the chamber 4 ₁ side from 4 ₂ to have been sectioning, the piston rod 4b that protrudes upward from the piston 4a penetrates the inside the piston rod 3b of the cushioning cylinder 3 is connected to the cushion pad 2, the upper chamber 4 ₁ locking valve 8 made of poppet valve for locking the rise of the cushion pad 2 between the lower chamber 4 ₂ is provided.
[0017]
The locking valve 8, the air in the air tank 18, have a poppet 8a which is operated by the switching valve 19, provided in the locking cylinder every four, ports _81, 82 opened and closed by poppet 8a Meanwhile 8 ₁ variable throttle valve 9 and line 10 with is connected to the upper chamber 4 ₁ locking cylinder 4 through the lower chamber 4 ₂ of the other port ₈₂ locking cylinder 4 via line 11 It is connected to the.
[0018]
Meanwhile the variable throttle valve 9 is provided on the midway of the conduit 10 connected to the port 8 ₁ of the locking valve 8 as shown in FIG. 2, it has a hollow piston 9a to open and close the conduit 10 Yes.
The piston 9a is movable in a direction orthogonal to the conduit 10, the end on the conduit 10 side is closed by a stopper 9b, and a screw 9c is formed on the inner peripheral surface of the other end. , One end of the rotary shaft 9d is screwed into the screw 9c. The other end side of the rotating shaft 9d is rotatably supported by a support member 9f by a bearing 9e, and a pulley 13 is attached to the other end portion. The pulley 13 is provided on the driving means 14 side. A timing belt 16 is provided between the pulleys 15, and the rotating shaft 9 d is rotated forward and backward by the driving means 14.
[0019]
The drive means 14 is composed of an electric motor with a cyclo reducer. The drive means 14 includes an opening degree detection means 17 such as a pulse encoder that detects the opening degree of the variable throttle valve 9 based on the rotation of the drive means 14. The opening detected by the opening detecting means 17 is fed back to a control means (not shown) for controlling the driving means 14.
[0020]
In FIG. 2, 9g is a non-rotating pin for blocking the rotation of the piston 9a and is implanted on the outer peripheral surface of the piston 9a. The tip side is formed on the support member 9f so as not to obstruct the movement of the piston 9a in the axial direction. It is inserted into the long slot-shaped guide groove 9h.
[0021]
Next, the operation of the above-configured die cushion device will be described with reference to FIG. 3 as well. A part of the lower mold (not shown) is placed on the cushion pad 2 via cushion pins. When a part of the lower die is pressed by the upper die that is lowered together with the slide (not shown), the air in the cushion cylinder 3 is compressed, and the cushion pad 2 is lowered as shown by the curve (A) in FIG. the oil of the lower chamber 4 the _second locking cylinder 4 flows into the upper chamber 4 ₁ through the check valve 7.
[0022]
When the slide and the cushion pad 2 reach the bottom dead center and the molding is completed and the slide starts to rise, the locking valve 8 is closed at this time. As shown in (), it is locked in that position and cannot be raised.
[0023]
Thereafter, when the locking valve 8 is opened, because the upper chamber 4 ₁ oil locking cylinder 4 flows into the lower chamber 4 ₂ through the locking valve 8, the cushion pad 2 by cushioning the cushion cylinder 3 of FIG. 3 curve While being raised as shown in (c), the rising speed V at this time can be freely adjusted by the opening of the variable throttle valve 9.
[0024]
In other words, in the case of press molding in which the die cushion capacity is large and the press speed (SPM) is set to be slow, if the cushion pad 2 rises at a fast speed after releasing the locking, the impact when the top dead center is reached is large and the top dead center is reached. Generates loud sounds and vibrations at points.
[0025]
In such a case, the ascending speed V is previously set slow as shown in FIG. As a result, the control means outputs a control signal to the drive means 14 provided in the variable throttle valve 9 so that the opening degree is adjusted to be small, so that the drive means 14 causes the piston 9a of the variable throttle valve 9 to flow oil flowing through the pipe line 10. The rotating shaft 9d is rotated so as to move in the squeezing direction.
[0026]
The opening degree detecting means 17 detects the opening degree of the variable throttle valve 9 by the rotation of the driving means 14 and feeds it back to the control means, and the control means sets the opening degree set in advance according to the die cushion capacity and the SPM. Then, the current opening degree input from the variable detection means 17 is compared, and the drive means 17 is feedback-controlled so that there is no deviation between them.
[0027]
And since the drive means 14 at the opening reaches the set value of the variable throttle valve 9 is stopped, the oil that flows from the upper chamber 4 ₁ locking cylinder 4 to the lower chamber 4 ₂ is throttled by the variable throttle valve 9 As shown in FIG. 3 (d), the cushion pad 2 rises at a slow speed and is slowly stopped when the top dead center is reached, so that it is possible to prevent the occurrence of a large impact or vibration. .
[0028]
On the other hand, when the die cushion capacity is small and the SPM is fast, if the rising speed V of the cushion pad 2 is slow, it cannot follow the rising speed of the slide, and the productivity decreases. In such a case, the opening degree of the variable throttle valve 9 is set to be large so that the rising speed V of the cushion pad 2 after releasing the locking is increased as shown in FIG.
[0029]
As a result, the cushion pad 2 reaches the top dead center before the slide reaches the top dead center, so that even when the SPM is fast, this can be dealt with. Even if the top dead center is reached, no impact or vibration is generated.
[0030]
When the die cushion capacity and the press speed are set according to the workpiece to be molded as described above, the optimum rising speed V of the cushion pad 2 can be freely adjusted according to the die cushion capacity and the press speed, so that the impact and vibration It is possible to perform press molding without generating production or reducing production capacity.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a die cushion device according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a variable throttle valve used in a die cushion device according to an embodiment of the present invention.
FIG. 3 is an operation explanatory view of a die cushion device according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Cushion pad 3 ... Cushion cylinder 4 ... Locking cylinder 4 ₁ ... Upper chamber 4 ₂ ... Lower chamber 8 ... Rocking valve 9 ... Variable throttle valve 14 ... Drive means 17 ... Opening degree detection means

Claims (3)

A cushion pad 2 which is elastically supported by the cushion cylinder 3, in the press of the die cushion apparatus having a locking cylinder 4 and the locking valve 8 for locking at the bottom dead center of the cushion pad 2,
The piston rod 4a of the locking cylinder 4 is connected to the cushion pad 2, the locking valve 8 opens and closes a conduit connecting the upper chamber 4 ₁ and the lower chamber 4 ₂ of the locking cylinder 4,
A variable throttle valve 9 having a configuration in which the opening degree is adjusted by moving the piston 9a in the axial direction by forward and reverse rotation of the electric motor, provided one in the pipe line;
By controlling the electric motor, characterized in that it comprises conduit by the locking valve 8 is when in the open, and control means for adjusting the flow rate of the oil flowing into the lower chamber 4 ₂ from the upper chamber 4 ₁ Die cushion device for press. An opening degree detecting means 17 for detecting the opening degree of the variable throttle valve 9 from the rotation of the electric motor is provided, and the opening degree detected by the opening degree detecting means 17 is fed back to a control means for controlling the electric motor. Item 2. A die cushion device for a press according to Item 1. Said control means includes a degree which is at least either one more set of die cushion capability and press speed, by comparing the opening degree inputted from the opening detection means 17, the opening degree of the variable throttle valve 9 The press die cushion apparatus according to claim 2, wherein the electric motor is controlled to have a set opening degree.

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