JPH04322933A - Work clamp device and method of controlling clamp pressure - Google Patents

Abstract

PURPOSE:To surely fix a workpiece with a suitable clamp pressure by automatically changing the clamp pressure in accordance with a kind of a machining process, and a material, shape, rigidity and the like of the workpiece with the use of an M function of an NC program. CONSTITUTION:In an NC machine tool for machining a workpiece in accordance with an NC program 62, a clamp pressure change-over circuit 60 for changing the clamp pressure among several stages is provided in a workpiece clamp device for clamping the workpiece by pressure fluid. The clamp pressure change- over circuit 60 is composed of three pressure reducing valves 22, 23, 24 and two solenoid valves 41, 42. As an instructing means for the NC device 61, an NC program 62 is used having an M function as an auxiliary function which includes clamp instructions for designating pressures in accordance with a clamp pressure such as a high pressure, middle pressure or a low pressure, that is, for example, three codes, M12 for a high pressure clamp, M13 for a middle pressure clamp and M14 for a low pressure.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is a work clamping device that clamps a workpiece using pressure fluid, and the workpiece clamping device changes the clamping pressure to an appropriate level depending on the type of machining, the material, shape, rigidity, etc. of the workpiece. This invention relates to a clamp pressure control method.

0002

[Prior Art] When fixing a workpiece, various methods such as mechanical, electromagnetic, and fluid methods are used. For example, as shown in FIG. There is something.

In FIG. 2, a workpiece 1 to be machined has a long shape, and the end face of the workpiece 1 is brought into contact with an end face stopper 2 for reference in the X direction, and the workpiece is pressed against a fixed clamper 3 for reference in the Y direction. Align the sides of 1,
The workpiece 1 is fixed between the fixed clamper 3 and the movable clamper 5 by operating the fluid pressure cylinder 4 to press the movable clamper 5 toward the workpiece 1 side.

In this case, it may be desirable to change the clamping pressure depending on whether the workpiece 1 is made of, for example, a thin-walled hollow section or a thick-walled hollow section. The pressure reducing valve was adjusted manually.

[0005]

[Problems to be Solved by the Invention] However, in the conventional method of changing the clamping pressure by manually adjusting the pressure reducing valve, it is difficult to adjust the pressure every time the type of machining, the material, shape, rigidity, etc. of the workpiece 1 changes. Since the pressure reducing valve must be adjusted manually each time, changing the clamp pressure becomes extremely troublesome, significantly reducing work efficiency, and being disadvantageous to automation of processing. The challenge was to solve these problems.

[0006]

[Object of the Invention] The present invention was made in view of the above-mentioned problems in the past, and it is possible to control the NC operation without manual adjustment.
The purpose is to enable automatic switching of clamp pressure by program.

[0007]

[Means for Solving the Problems] A clamping pressure control method for a workpiece clamp device according to the present invention is a workpiece clamping device that clamps a workpiece using pressure fluid in an NC machine tool that performs machining based on an NC program. A clamp pressure switching circuit that can switch the pressure in multiple stages is provided, and multiple M codes are set to specify each of the above clamp pressures in the M function of the NC program to issue a clamp command, and the workpiece is clamped by the commands of these M codes. It is characterized by controlling a pressure switching circuit to switch to a designated clamp pressure, and this clamp pressure control method for a workpiece clamp device is a means for solving the above-mentioned conventional problems.

The clamping pressure control method for a workpiece clamping device according to the present invention has the above-described configuration, and various workpieces having different materials, shapes, rigidities, etc. can be used as the workpieces.

[0009] Furthermore, as the pressure fluid for clamping the workpiece, pneumatic pressure, hydraulic pressure, or the like may be used.

0010

[Operation of the invention] In the clamping pressure control method for a workpiece clamping device according to the present invention, an appropriate clamping pressure corresponding to the type of machining, the material, shape, rigidity, etc. of the workpiece to be machined can be specified using the M code of the NC program. , this M
Clamp pressure is automatically switched according to code commands. Therefore, there is no need for manual adjustment, and the pressure is set reliably to prevent misalignment of the workpiece when the clamping pressure is too low, or deformation of the workpiece when the clamping pressure is too high. The occurrence of defects will be prevented.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a workpiece clamping device used in an NC machine tool according to the present invention, which is equipped with a clamping pressure switching circuit 60. Figure 2
In this case, three fluid pressure cylinders 4 are shown, but only two are shown in FIG. 1, and the number of fluid pressure cylinders 4 can be selected as appropriate.

As shown in FIG. 1, a fluid pressure supply side fluid passage 11 connected to a fluid pressure supply side (not shown) is divided into three branch fluid passages 12, 13, and 14 in this embodiment.

Among these, the first high-pressure side branch fluid flow path 12 is supplied with fluid pressure at a high pressure (for example, 3.0 kgf).
/cm2) and a silencer 32, and a second intermediate pressure side branch fluid flow path 13.
For example, the fluid pressure should be medium pressure (for example, 2.0 kgf/cm2
) Medium pressure reducing valve 23 and silencer 3 set to
3, and the third low pressure side branch fluid flow path 14 is provided with a low pressure reducing valve 24 and a silencer 34 for setting the fluid pressure to a low pressure (for example, 1.0 kgf/cm2).

The medium pressure side branch fluid flow path 13 is connected to the P port of the medium/low pressure side switching valve 41 of the three-port, two-position switching type, and the low pressure side branch fluid flow path 14 is connected to the medium/low pressure side switching valve 41. It is connected to the R port of another 3-port, 2-position high-pressure side switching valve 42 via the R port of the switching valve 41 and the A port of the medium/low pressure side switching valve 41.

On the other hand, the high pressure side branch fluid flow path 12
It is connected to the P port of the low pressure side switching valve 42.

Further, a fluid pressure consumption side fluid passage 43 is connected to the A port of the high/low pressure side switching valve 42. That is, the clamp pressure switching circuit 60 is controlled by the three pressure reducing valves 22, 23, 24 and the two switching valves 41, 42.
is configured.

A flexible tube 44 is connected to the fluid pressure consumption side fluid passage 43, and is further connected to the P port of a clamp/unclamp switching valve 45.

The clamp/unclamp switching valve 45 is a 5-port, 2-position switching valve, and an unclamping side silencer 46 is connected to the EA port, and an E
A clamp-side silencer 47 is connected to the B port.

The A port of the clamp/unclamp switching valve 45 is connected to the clamp side of the fluid pressure cylinder 4 via a flexible tube 51 and a discharge side flow rate adjustment valve 52 with a check valve for adjusting the unclamp speed. The B port of the clamp/amplifier switching valve 45 is connected to the port 4a, and the B port of the clamp/amplifier switching valve 45 is connected to the amplifier of the fluid pressure cylinder 4 via a flexible tube 53 and a discharge side flow rate adjustment valve 54 with a check valve for adjusting the clamp speed. It is connected to the clamp side port 4b.

[0020]The three switching valves 41, 42, 4
5 is switched and controlled by a command from an NC device 61.

[0021] Also, as a command means to the NC device 61, N
Using the C program 62, the M function, which is an auxiliary function of this program 62, is used as a clamp command to specify clamp pressures corresponding to the above-mentioned high pressure, medium pressure, and low pressure, respectively.For example, high pressure clamp is set to M12, medium pressure clamp Set three M codes: M13 for M13 and M14 for low pressure clamp.

When creating an NC program, for example, as shown in FIG. 3, the above M code corresponding to the clamp pressure is specified as a clamp command. As a result, the NC device 61 reads the M code from the NC program 62 and issues a clamp command for the specified clamp pressure.

When fixing the workpiece 1 with the clampers 3 and 5 using the clamping force switching circuit of the workpiece clamping device having such a configuration, when fixing the workpiece 1 with a smaller clamping pressure, the NC By specifying M14 in the program 62, the NC device 6
1 reads this M code and issues a low pressure clamp command,
Set the medium/low pressure side switching valve 41 and the high/low pressure side switching valve 42 to the low pressure side ports 41a, 42a shown in the figure, respectively, and move the clamp/unclamp switching valve 45 to the clamp side port 45a, which is different from the one shown in the figure. Switch.

Therefore, the fluid pressure set to a low pressure of, for example, 1.0 kgf/cm2 by the low pressure reducing valve 24 is transferred to the low pressure side port 41a of the medium/low pressure side switching valve 41, the high/low pressure side port 41a,
The clamp side port 4a of the fluid pressure cylinder 4 via the low pressure side port 42a of the low pressure side switching valve 42, the clamp side port 45a of the clamp/unclamp switching valve 45, and the check valve 52a of the discharge side flow adjustment valve 52 with check valve. The movable clamper 5 is pressed toward the workpiece 1, and the workpiece 1 is pressed with low pressure by the clampers 3 and 5.
The fluid flowing out from the unclamp side port 4b is connected to the flow rate adjustment valve 54b of the discharge side flow rate adjustment valve 54 with a check valve, the clamp and
It is discharged through the clamp-side port 45a of the unclamp switching valve 45 and the clamp-side silencer 47.

At this time, the clamping speed by the fluid pressure cylinder 4 is adjusted by the flow rate adjustment valve 54b of the discharge side flow rate adjustment valve 54 with a check valve.

When releasing the fixation of the workpiece 1, the clamp/unclamp switching valve 45 is placed at the unclamp side port 45b shown in the figure.

[0027] As a result, the fluid pressure consumption side fluid flow path 4
3 enters the unclamping side port 4b of the fluid pressure cylinder 4 through the unclamping side port 45b of the clamp/unclamping switching valve 45 and the check valve 54a of the discharge side flow rate adjustment valve 54 with check, and enters the unclamping side port 4b of the fluid pressure cylinder 4 to the movable side. While separating the clamper 5 from the workpiece 1, the clamp side port 4a
The fluid flowing out is discharged through the flow rate adjustment valve 52b of the discharge side flow rate adjustment valve 52 with a check valve, the unclamp side port 45b of the clamp/unclamp switching valve 45, and the unclamp side silencer 46.

At this time, the unclamping speed by the fluid pressure cylinder 4 is adjusted by the flow rate adjustment valve 52b of the discharge side flow rate adjustment valve 52 with a check valve.

On the other hand, when fixing the workpiece 1 with a medium clamping pressure, M1 is set in the NC program 62.
3, the NC device 61 reads this M code and issues a medium pressure clamp command, sets the medium/low pressure side switching valve 41 to a position of the medium pressure side port 41b that is different from the one shown in the diagram, and also sets the medium pressure side switching valve 41 to a position different from that shown in the figure. Set the switching valve 42 to the low pressure side port 42a shown in the figure, and close the clamp/unclamp switching valve 45.
to the position of the clamp side port 45a.

Therefore, the fluid pressure set to an intermediate pressure of, for example, 2.0 kgf/cm2 by the intermediate pressure reducing valve 23 is transferred to the intermediate pressure side port 41b of the intermediate/low pressure side switching valve 41,
The clamp side port 4a of the fluid pressure cylinder 4 via the low pressure side port 42a of the low pressure side switching valve 42, the clamp side port 45a of the clamp/unclamp switching valve 45, and the check valve 52a of the discharge side flow adjustment valve 52 with check valve. The movable clamper 5 is pressed toward the workpiece 1, and the workpiece 1 is pressed with medium pressure by the clampers 3 and 5.
The fluid flowing out from the unclamp side port 4b is connected to the flow rate adjustment valve 54b of the discharge side flow rate adjustment valve 54 with a check valve, the clamp and
It is discharged through the clamp-side port 45a of the unclamp switching valve 45 and the clamp-side silencer 47.

On the other hand, when fixing the workpiece 1 with a larger clamping pressure, the NC program 62 has M
12, the NC device 61 reads this M code, issues a high pressure clamp command, and sets the medium/low pressure side switching valve 41 to the low pressure side port 41a position shown in the figure as standard, and depending on the situation, Medium pressure side port 4 different from
1b, the high/low pressure side switching valve 42 is set to a high pressure side port 42b position different from that shown in the figure, and the clamp/unclamp switching valve 45 is switched to a position of the clamp side port 45a.

Therefore, the fluid pressure set to a high pressure of, for example, 3.0 kgf/cm2 by the high pressure reducing valve 22 is applied to the high pressure side port 42b of the high/low pressure side switching valve 42 and the clamp side port of the clamp/unclamp switching valve 45. 45
a and check valve 52a of discharge side flow rate adjustment valve 52 with check valve
and enters the clamp side port 4a of the fluid pressure cylinder 4 to press the movable side clamper 5 toward the workpiece 1,
The workpiece 1 is pressed with high pressure by the clampers 3 and 5, and the fluid flowing out from the unclamp side port 4b is controlled by the flow rate adjustment valve 54a of the discharge side flow rate adjustment valve 54 with a check valve and the clamp/unclamp switching valve 45. Clamp side port 4
5a and the clamp-side silencer 47.

[0033] In the above embodiment, the set pressure is 3.
Although the case where there are three types has been shown, it goes without saying that the case is not limited to the case where there are three types.

Furthermore, the plurality of branch fluid passages that branch the fluid pressure supply side fluid passage and set the fluid pressure to a predetermined value are each provided with a pressure reducing valve in each of the branched fluid passages. Although it is possible to have different fluid pressures exiting each branch fluid flow path, it is also possible, for example, to not provide a pressure reducing valve in one branch fluid flow path so that the fluid pressure on the fluid pressure supply side It is also possible to set the fluid pressure to be the same as that of the branch fluid flow channel, and to provide pressure reducing valves in each of the other branch fluid flow channels so that the fluid pressure exiting each branch fluid flow channel has a different value.

Furthermore, the switching valve for selecting the plurality of branch fluid flow paths is, for example, a reciprocating type switching valve that selects a branch fluid flow path by switching between a plurality of reciprocating positions such as two or three positions. Alternatively, the switching valve can be of a rotating type in which branch fluid channels are connected at multiple positions in the circumferential direction and the branch fluid channel is selected by rotation, and there are no particular limitations on the structure of the switching valve. .

[0036]

Effects of the Invention According to the clamping pressure control method for a workpiece clamping device according to the present invention, the M function of the NC program adjusts the clamping pressure on the workpiece depending on the type of machining, the material, shape, rigidity, etc. of the workpiece. can be switched automatically. Therefore, there is no need for manual adjustment, the pressure is set reliably, and it is possible to secure the workpiece with an appropriate clamping pressure, which prevents the workpiece from shifting due to too low clamping pressure. , it is possible to prevent defects such as deformation of the workpiece due to too high clamping pressure, and it has the remarkable effect of making it possible to efficiently fix the workpiece with an appropriate force. brought about.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a work clamping device according to the present invention.

FIG. 2 is an explanatory plan view showing a clamped state of a workpiece.

FIG. 3 is an explanatory diagram showing an example of an NC program.

[Explanation of symbols]

1 Workpiece to be processed 3,5 Clamper 4 Fluid pressure cylinder 11 Fluid pressure supply side fluid flow path 12 High pressure side branch fluid flow path 13 Medium pressure side branch fluid flow path 14 Low pressure side branch fluid flow path 41 Medium/low pressure side switching valve 42 High/low pressure side switching valve 43 Fluid pressure consumption side fluid flow path. 60 Clamp pressure switching circuit 61 NC device 62 NC program

Claims (1)

[Claims] Claim 1: In an NC machine tool that performs machining based on an NC program, a work clamp device that clamps a workpiece to be machined using pressure fluid is provided with a clamp pressure switching circuit capable of switching the clamp pressure in multiple stages, and A workpiece characterized in that a plurality of M codes are set for specifying each of the above-mentioned clamping pressures in the M function to issue a clamping command, and the workpiece clamping pressure switching circuit is controlled by the commands of the M-codes to switch to the specified clamping pressure. Clamp pressure control method for clamp device.