JP3710856B2 - Press control method and control apparatus for hydraulic press machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a press control method and a control apparatus for a hydraulic press machine.
[0002]
[Prior art]
Conventionally, for example, a hydraulic circuit as shown in FIG. 8 is used to operate a ram cylinder provided in a hydraulic press machine.
[0003]
That is, the hydraulic circuit 101 is provided with a pump 107 driven by a pump motor 105 communicated with the tank 103, and a discharge side pipe 109 of the pump 107 is connected to a P port of the electrohydraulic servo valve 111. .
[0004]
When the flow path of the electrohydraulic servo valve 111 is switched to connect the P port and the A port, and the B port and the T port, the pressure oil flows into the upper oil chamber 117 of the ram cylinder 115 through the pipe 113. The piston 119 is lowered. As the piston 119 descends, the oil in the lower oil chamber 121 of the ram cylinder 115 passes through the pipe line 123 and is returned from the B port of the electrohydraulic servo valve 111 via the T port to the tank 103 through the return pipe 125. . Reference numeral 127 denotes an accumulator.
[0005]
When the flow path of the electro-hydraulic servo valve 111 is switched to connect the P port and the B port, and the A port and the T port, the pressure oil flows into the lower oil chamber 121 of the ram cylinder 115 through the pipe line 123, and the piston 121 is raised. At this time, the oil in the upper oil chamber 117 of the ram cylinder 115 is returned to the tank 103 from the pipe 113 through the return pipe 125 via the A and T ports.
[0006]
As the control device 129 for opening and closing the electrohydraulic servo valve 111, the control device 129 creates a press pattern as shown in FIG. 9 and controls the electrohydraulic servo valve 111 via the amplifier 131. As shown in FIG. 9, the press pattern is a curved portion A near the lower end of the ram stroke, and a V-shaped press pattern including a curve connected by the curved portion B near the upper end. Yes.
[0007]
[Problems to be solved by the invention]
By the way, when the ram cylinder 115 provided in the above-described conventional hydraulic press machine is driven and controlled, in order to increase the speed, an oil hammer is generated when the speed of raising and lowering the piston 119 of the ram cylinder 115 is increased. This oil hammer occurs due to a sudden change in the oil flow, and causes problems such as noise when the ram cylinder 115 is operated and shortened piping life.
[0008]
Therefore, the operation of the ram cylinder 115 is controlled by the press pattern shown in FIG. 9 with a curve such as a part A at the stroke descending end of the ram cylinder 115 and a curve such as the B part at the rising end. I try to prevent the occurrence of hammer. However, in the V-shaped press pattern including this curve, there is a problem that the press time per cycle becomes long and the speed cannot be further increased.
[0009]
The object of the present invention is to increase the speed by eliminating the curved portion of the press pattern in a short ram stroke in which no oil hammer occurs, and to provide a curved portion in the press pattern in a long ram stroke in which an oil hammer occurs to increase the speed and reduce the speed. It is an object of the present invention to provide a press control method and a control apparatus for a hydraulic press machine that solve both of the noises.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the press control method for a hydraulic press machine of the present invention according to claim 1 is the reference stroke in which the actual ram stroke of the ram cylinder provided in the hydraulic press machine is a reference for the occurrence of oil hammer. If shorter, as well as select a press pattern of straight V-shaped, based on the press pattern of the selected linear V-shaped, opening and closing controls the servo valve provided in a hydraulic circuit allowed to operate the ram cylinder,
If the actual stroke of the ram cylinder is long beyond the reference stroke selected press pattern of V shape including a curve connecting portion rising edge near the falling edge near a curve, including the selected curve portion The servo valve is controlled to open and close based on a V-shaped press pattern.
[0011]
According to a second aspect of the present invention, there is provided a press control control device for a hydraulic press machine according to the present invention, wherein the hydraulic circuit for driving the ram cylinder is provided with a servo valve for circuit switching.
When the actual stroke of the ram cylinder is shorter than a reference stroke which is a reference for the occurrence of oil hammer , a straight V- shaped press pattern is selected , and the straight V- shaped press pattern is selected based on the selected straight V-shaped press pattern. controls the opening and closing of the servo valve, when the actual stroke of the ram cylinder is long beyond the reference stroke, V-shaped including a curve connecting portion rising edge near the falling edge near the curve of the ram stroke press A press control for selecting a pattern and controlling opening and closing of the servo valve based on a V-shaped press pattern including the selected curved portion is provided.
[0013]
When the actual ram stroke is shorter than the reference stroke, in other words, in the case of a short ram stroke in which no oil hammer occurs , by using the press control method and the control device for the hydraulic press machine according to claims 1 and 2 described above. In this case, the servo valve is controlled to be opened and closed using a straight V- shaped press pattern to increase the speed. Further, when the actual stroke is longer than the reference stroke, the servo valve is controlled to be opened and closed using a V- shaped press pattern including a curved portion, so that the oil hammer is eliminated and the noise is reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0015]
First, in order to facilitate understanding, a turret punch press, for example, as a hydraulic press machine will be schematically described.
[0016]
Referring to FIG. 7, the turret punch press 1 includes a gate-shaped frame 3, and this frame 3 is provided with a side frame 7 standing on a lower base 5 and a lower base 5, and an upper portion of the side frame 7. The upper frame 9 is provided.
[0017]
A rotatable lower turret 11 is supported on the lower base 3, and a plurality of dies D are mounted on the circumference of the lower turret 11 at appropriate intervals. A rotatable upper turret 13 corresponding to the lower turret 11 is supported on the upper frame 9, and a plurality of punches P are mounted on the upper turret 13 at a position corresponding to the die D.
[0018]
The position of the die D and the punch P mounted on the right side in FIG. 7 of the lower and upper turrets 11 and 13 is the processing position, and the striker 15 is placed on the upper frame 9 above the punch P at the processing position. Is provided to be movable up and down.
The striker 15 is connected to a hydraulic cylinder 17 provided in the upper frame 9 via, for example, a ram 19.
[0019]
A carriage base 21 that is movable in the Y-axis direction (left-right direction in FIG. 7) is provided at the right end in FIG. 7 on the lower base 5. The carriage base 21 has an X-axis direction (FIG. 7). The carriage 23 is provided so as to be movable in a direction perpendicular to the paper surface. The carriage 23 is provided with a plurality of work clamps 25 that clamp the work W at appropriate intervals in the X-axis direction.
[0020]
With the above configuration, by moving the carriage base 21 in the Y-axis direction and the carriage 23 in the X-axis direction, the workpiece W clamped by the workpiece clamp 25 provided in the carriage 23 moves in the X-axis and Y-axis directions. Thus, the desired position of the workpiece W is positioned at the machining position.
[0021]
In a state where the desired position of the workpiece W is positioned at this processing position, the upper and lower turrets 13 and 11 are rotated to index and position the desired punch P and die D at the processing position. Next, by driving the hydraulic cylinder 17 and moving the striker 15 up and down via the ram 19, a normal punching process is performed at a desired position of the workpiece W by the cooperation of the punch P and the die D. .
[0022]
Next, a hydraulic circuit 27 for driving the hydraulic cylinder 17 as a main part as an example of the embodiment of the present invention and a control device 29 for controlling the movement of the hydraulic cylinder 17 will be described in detail.
[0023]
Referring to FIG. 1, a piston 33 having a piston rod 31 is built in the hydraulic cylinder 17, and an upper oil chamber 35 and a lower oil chamber 37 are formed. Then, when pressurized oil is supplied into the upper oil chamber 35, the piston 33 is pressed and lowered, and although not shown, the punch P is struck through the ram 19, and the workpiece W is punched in cooperation with the die D. Is given. When pressurized oil is supplied into the lower oil chamber 37, the piston 33 rises and returns to the standby position.
[0024]
The hydraulic circuit 27 is provided with a pump 43 driven by a pump motor 41 communicated with a tank 39, and a discharge side pipe 45 of the pump 43 is connected to a P port of an electrohydraulic servo valve 47.
[0025]
Then, when the flow path of the electrohydraulic servo valve 47 is switched to connect the P port and A port, and the B port and T port, the pressure oil flows into the upper oil chamber 35 of the hydraulic cylinder 17 through the conduit 49. The piston 33 is lowered. As the piston 33 descends, the oil in the lower oil chamber 37 of the hydraulic cylinder 17 passes through the pipe 51, returns from the B port of the electrohydraulic servo valve 47 through the T port, and returns to the tank 39 through the return pipe 53. . Reference numeral 55 denotes an accumulator.
[0026]
When the flow path of the electro-hydraulic servo valve 47 is switched to connect the P port and the B port, and the A port and the T port, the pressure oil flows into the lower oil chamber 37 of the hydraulic cylinder 17 through the pipe 51, and the piston Raise 33. At this time, the oil in the upper oil chamber 35 of the hydraulic cylinder 17 is returned to the tank 39 from the conduit 49 through the A and T ports, through the return conduit 53.
[0027]
The control device 29 for controlling the opening / closing of the electrohydraulic servo valve 47 includes a machining program 57 containing information such as plate thickness, an NC device 59 for positioning the workpiece by the machining program 57, and positioning the workpiece. As a means, a position detector 65 connected to the motor 63 via an amplifier 61 is provided.
[0028]
A press control 67 for outputting a press activation signal from the NC device 59 and inputting the output after positioning the workpiece by the NC device 59 is provided. In the press control 67, a ram stroke is calculated based on the plate thickness information of the machining program 57, a press pattern is created, and the electrohydraulic servo valve 47 is opened and closed via the amplifier 69 by this press pattern. The hydraulic cylinder 17 is controlled to lower and the workpiece is punched.
[0029]
With the configuration as described above, its operation will be described in detail with reference to the flowchart shown in FIG.
[0030]
First, in step S1, the press stroke is determined based on the plate thickness information of the machining program 57. As shown in FIG. 3, the press stroke is the thickness H of the workpiece, the distance U from the upper surface of the workpiece W to the rising end of the piston 33 of the hydraulic cylinder 17, and the hydraulic pressure from the lower surface of the workpiece W. The distance D to the descending end of the piston 33 of the cylinder 17 is added.
[0031]
Next, the reference press stroke that is set in advance in step S2 (the reference stroke that is a reference for the presence or absence of the occurrence of the oil hammer) The actual press stroke L is L ≦ Lo or L> with respect to Lo. Judge whether it is Lo.
[0032]
If L ≦ Lo, that is, if the actual press stroke L is shorter than the preset press stroke Lo, the process proceeds to step S3. In step S3, a straight V-shaped press pattern is created. This straight V-shaped press pattern is shown in FIG. 4 and FIG. 5, and the press pattern shown in FIG. 4 is a complete V-shaped straight line. The press pattern shown in FIG. It is a straight V-shaped part in which a cut portion S is formed in the middle of descending.
[0033]
When L> Lo, that is, when the actual press stroke L is longer than the preset press stroke Lo, the process proceeds to step S4. In step S4, a V-shaped press pattern including a curved portion is created. The V-shaped press pattern including the curved portion is shown in FIG. 6, and the press pattern shown in FIG. 6 forms a curved portion A near the lower end of the press stroke, and near the upper end of the press stroke. It is a V shape including the curved portion where the curved portion B is formed. You may provide the deceleration part between SS of FIG. 5 in the part of the workpiece | work thickness in the downward stroke.
[0034]
The press pattern in which the step S3 or the step S4 is selected is output in step S6 when the press activation is turned on in step S5, and the punching is performed by operating the hydraulic cylinder 17 by controlling the opening / closing of the electrohydraulic servo valve 47. Processing.
[0035]
As described above, when the actual press stroke L is shorter than the preset press stroke Lo, a straight V-shaped press pattern is used, so that the press time of one cycle can be shortened and the speed can be increased. At the same time, since the press stroke Lo is short, the oil flow rate is small and no oil hammer occurs.
[0036]
In addition, when the actual press stroke L is longer than a preset reference press stroke Lo , a V-shaped press pattern including a curved portion is used, so that the occurrence of an oil hammer can be prevented by this curved portion. Therefore, noise reduction can be achieved.
[0037]
In addition, this invention is not limited to the example of embodiment of invention mentioned above, It can implement in another aspect by making an appropriate change. For example, in the embodiment of the present invention, the turret punch press 1 has been described as an object. However, if the press stroke is variable by a hydraulic press, not only punch presses but also shearing, venting machines, etc. Can also be adopted.
[0038]
【The invention's effect】
As can be understood from the description of the example of the embodiment as described above, according to the present invention according to claims 1 and 2, when the press stroke of the ram cylinder is shorter than the reference stroke, a straight V-shaped press pattern is displayed. When the press stroke of the cylinder is longer than the reference stroke , a V- shaped press pattern including a curved portion is selected. Then, the selected press pattern is used to control the opening and closing of a servo valve provided in a hydraulic circuit that drives the ram cylinder to operate the ram cylinder to process the workpiece.
[0039]
Thus, when the press stroke using the linear press pattern is short, the press time for one cycle can be shortened and the speed can be increased. In this case, since the oil flow rate is small, no oil hammer is generated.
[0040]
Further, when the press stroke using the V-shaped press pattern including the curved portion is long, the oil hammer can be prevented by the curved portion of the press pattern, and the noise can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a hydraulic circuit for driving a hydraulic cylinder and a control device for controlling the hydraulic circuit, showing the main part of the present invention.
FIG. 2 is a flowchart illustrating the operation of the present invention.
FIG. 3 is an explanatory diagram of a press pattern.
FIG. 4 is an explanatory diagram of a straight V-shaped press pattern.
FIG. 5 is an explanatory diagram of a straight V-shaped press pattern.
FIG. 6 is an explanatory diagram of a V-shaped press pattern including a curved portion.
FIG. 7 is an explanatory front view showing a schematic configuration of a hydraulic turret punch press according to an embodiment of the present invention.
FIG. 8 is an explanatory diagram of a hydraulic circuit that drives a hydraulic cylinder and a control device that controls the hydraulic circuit, showing a conventional example.
FIG. 9 is an explanatory diagram of a V-shaped press pattern including a curved portion, showing a conventional example.
[Explanation of symbols]
1 Turret punch press (hydraulic press machine)
17 Hydraulic cylinder (ram cylinder)
27 Hydraulic circuit 29 Control circuit 47 Electro-hydraulic servo valve 67 Press controller

Claims (2)

The actual ram stroke of the ram cylinder with a hydraulic press machine is shorter than the reference stroke which is a reference of the occurrence of oil hammer, selects a press pattern of straight V-shaped, of the selected linear V-shaped based on a press pattern, as well as opening and closing control of the servo valve provided in a hydraulic circuit allowed to operate the ram cylinder,
If the actual stroke of the ram cylinder is long beyond the reference stroke selected press pattern of V shape including a curve connecting portion rising edge near the falling edge near a curve, including the selected curve portion A press control method for a hydraulic press machine, wherein the servo valve is controlled to open and close based on a V-shaped press pattern. A hydraulic press machine equipped with a servo valve for circuit switching to the hydraulic circuit that drives the ram cylinder,
When the actual stroke of the ram cylinder is shorter than a reference stroke which is a reference for the occurrence of oil hammer , a straight V- shaped press pattern is selected , and the straight V- shaped press pattern is selected based on the selected straight V-shaped press pattern. controls the opening and closing of the servo valve, when the actual stroke of the ram cylinder is long beyond the reference stroke, V-shaped including a curve connecting portion rising edge near the falling edge near the curve of the ram stroke press A press control control device for a hydraulic press machine, comprising a press control for selecting a pattern and controlling opening and closing of the servo valve based on a V-shaped press pattern including a selected curved portion .

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