JP4164959B2 - Rotary axis control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary shaft control device that executes an origin return operation of a rotary shaft of, for example, a numerically controlled machine tool.
[0002]
[Problems to be solved by the invention]
For example, in a numerically controlled machine tool, there is one in which a work surface of a workpiece is changed by freely rotating an index table that holds the workpiece by a chuck mechanism by a servo motor. In such an index table, an operation for returning to the origin position is performed at an appropriate time. Conventionally, an index table is used to perform an origin return operation of the rotary shaft using a dog switch.
[0003]
That is, FIG. 7 schematically shows a state from the back side of the index table 1. Here, in the index table 1 as a rotating shaft, the shaft 2 is driven by a servo motor (not shown), and the forward direction (clockwise direction indicated by “+” in the drawing) and the reverse direction (counterclockwise indicated by “−” in the drawing). It can be freely rotated in the direction of rotation). Further, for example, a position where a predetermined origin O of the index table 1 coincides with the upper part (0 degree) is set as the origin position.
[0004]
A dog 3 is provided on the outer peripheral portion of the index table 1 at a position slightly closer to the forward direction than the origin O. On the apparatus side (fixed side), the dog 3 is slightly closer to the reverse direction than the 0 degree position. A dog switch 4 that is turned on by the dog 3 is provided at the position. In this case, the dog 3 turns on the dog switch 4 in the range of 2 to 3 degrees.
[0005]
Thus, for example, when the origin return key on the operation panel is turned on, the index table 1 is rotated at a high speed in the forward direction from the position shown in FIG. 7A, for example, and is switched to a low speed rotation when the dog switch 4 is turned on. When the dog switch 4 is turned off by a predetermined amount, the index table 1 is stopped and the origin is returned. In this case, the return to origin can be performed reliably in a short time.
[0006]
By the way, a cable 5 (or a hose for supplying air) for operating the chuck mechanism is connected to the index table 1. When the cable 5 is rotated in one direction without limitation, the cable 5 There is a concern that the shaft 2 may be wound and eventually disconnected. That is, when the origin return operation in the positive direction as described above is performed from the state where the dog 3 is positioned on the positive direction side of the dog switch 4 as shown in FIG. ), The index table 1 stops at a position rotated 360 degrees in the forward direction from the original 0 degree position, and the cable 5 is wound around the shaft 2.
[0007]
Therefore, conventionally, in order to deal with such a problem, the actual stop position of the index table 1 (servo motor) is always stored in the backup RAM, and the dog 3 is more positive than the dog switch 4 when returning to the origin. If the index table 1 is positioned in the reverse direction, the index table 1 is temporarily rotated in the reverse direction to return the dog 3 to the reverse direction side of the dog switch 4, and then the index table 1 is rotated in the forward direction to perform the origin return operation. ing.
[0008]
However, in the above, it is effective when the storage of the backup RAM and the stop position of the index table 1 match, but for example, when the contents of the backup RAM are cleared by replacing the board at the time of repair, When the power is turned off while the index table 1 is rotating, or when the index table 1 is rotated for some reason while the power is turned off, there is a discrepancy between the storage in the backup RAM and the actual stop position of the index table 1. When this occurs, there is still a possibility that the cable 5 is wound around the shaft 2 due to the return to origin operation and is disconnected.
[0009]
The present invention has been made in view of the above circumstances, and its purpose is to connect a cable or the like to the rotating shaft, even if the stored position of the rotating shaft and the actual position of the rotating shaft are inconsistent. Another object of the present invention is to provide a rotary shaft control device that can prevent disconnection of a cable or the like due to the origin return operation of the rotary shaft.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a rotating shaft control apparatus according to claim 1 of the present invention comprises an origin returning control means for returning a rotating shaft to an origin position based on an operation of a dog switch, and the origin returning control is provided. Means When the origin return is instructed by the normal operation of the operating means, if the dog switch is in the on state, the rotating shaft is rotated at a low speed in the forward direction to return to the origin position, and if the dog switch is in the off state, the rotation is performed. The shaft is rotated at a high speed in the forward direction from the opposite side of the on operation position until the dog switch is turned on, and after the dog switch is turned on, the rotating shaft is rotated at a low speed in the forward direction to return to the origin position. When the origin return is instructed by special operation of the operating means, if the dog switch is on, Rotate the rotation axis in the forward direction at low speed to return to the origin position The home position returning operation is performed, and when the dog switch is in an OFF state, the home position returning operation is prohibited and an error notification is performed.
[0011]
According to this, when it becomes impossible to determine on the device side whether the stop position of the rotary shaft is located on the forward direction side or the reverse direction side with respect to the dog switch, the operator performs a special operation of the operation means. When the home position return is instructed, the home position return operation is performed only when the dog switch is in the ON state, and in other states, the home position return operation is not performed and an error is notified. Therefore, when an origin return is instructed by a special operation, the origin return operation is performed only when it is certain that the cable connected to the rotating shaft will not be broken even if the origin return operation is performed. It becomes like this.
[0012]
At this time, manual operation means for freely rotating the rotary shaft by remote manual operation may be provided (invention of claim 2). According to this, when there is a possibility of an error when instructing the return to origin by a special operation, or when an error notification is made once, the operator freely rotates the rotating shaft by manual operation means. So that the position where no error occurs, that is, the position where the dog switch is turned on, can be easily moved, and then the origin return operation of the rotating shaft can be performed by instructing the origin return by a special operation. Become.
[0013]
Further, in this case, if display means for displaying the on / off state of the dog switch is provided (invention of claim 3), the operator looks at the display means to determine whether the dog switch is in the on state, that is, a special operation. Thus, it is possible to easily know whether or not an error occurs when instructing the return to origin, and when performing the operation by the manual operation means, the operation can be performed more easily.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment (corresponding to claims 1 to 3) in which the present invention is applied to an index table of a numerically controlled machine tool will be described with reference to FIGS. First, FIG. 4 shows the external configuration of the main part of the main body of the numerically controlled machine tool (machining center) 11. Here, a column 13 is provided on the base 12 so as to extend upward. A headstock 15 can be moved up and down along a linear guide 14 provided on the front surface of the column 13 so as to extend in the vertical direction. It is supported by.
[0015]
The column 13 is provided with a Z-axis motor 16 and a ball screw mechanism (only a ball screw 17 is shown) for freely moving the headstock 15 in the vertical direction (Z-axis direction). A well-known XY table 18 is provided on the front surface of the base 12, and an index table 19, which will be described later, is attached to the XY table 18 as a rotating shaft. The XY table 18 is freely moved in the front-rear (X-axis) direction and the left-right (Y-axis) direction by driving an X-axis motor 20 and a Y-axis motor 21 (both are shown only in FIG. 3). The work W (see FIG. 5) supported by the index table 19 is freely moved in the XY directions.
[0016]
The headstock 15 is provided with a machining head 22 and a rotary tool magazine 23 and a tool changer 24. The machining head 22 has a main shaft 25 at its lower part and a main shaft motor 26 for rotating the main shaft 25 at its upper part. A tool 27 is replaceably attached to the main shaft 25.
[0017]
The tool magazine 23 has a plurality of tool pots for accommodating various tools 27 in a ring shape, and is rotated by driving of a magazine motor 28 so that a necessary tool pot (tool 27) is moved to the lowermost part. The tool is placed at the tool entry / exit position. Further, the tool changer 24 rotates the tool change arm 30 by driving a tool change motor 29 to exchange the tool 27 positioned at the tool entry / exit position with the tool 27 attached to the main shaft (tool 27). If there is only one of them, the tool is transferred to the other).
[0018]
As shown in FIG. 5, the index table 19 has a disk shape and rotates about a B axis extending in the left-right direction (parallel to the Y-axis direction) via a shaft 31 extending on the back side of the center portion. It is provided as possible. At this time, a chuck mechanism 32 is provided on the front side of the index table 19 (the side facing the left side in FIG. 4) to hold the workpiece W so as to sandwich the workpiece W from four directions. As shown in FIG. 2, a cable 33 for driving the chuck mechanism 32 is led out from the back side of the index table 19.
[0019]
The index table 19 (shaft 31) is freely rotated by a B-axis motor 34. As a result, the workpiece W is freely rotated by the drive of the B-axis motor 34 while being held on the front surface of the index table 19 by the chuck mechanism 23, so that the surface to be processed is changed. It is.
[0020]
FIG. 3 schematically shows the electrical configuration of the machine tool 1, and the machine tool 1 is provided with a control circuit 35 that performs overall control. The control circuit 35 is mainly composed of a microcomputer including a CPU, a ROM, a RAM, and the like, and via the motor drive circuit (servo driver) (not shown), the spindle motor 26, the X-axis motor 20, the Y-axis motor 21, The Z-axis motor 16, the B-axis motor 34, the magazine motor 28, and the tool change motor 29 are controlled. Each of these motors is provided with an encoder, and feedback control is performed by the output of this encoder.
[0021]
Thus, the control circuit 35 attaches the necessary tool 27 to the spindle 25 in accordance with the NC program inputted in advance, and indexes the work surface of the workpiece W by the index table 19, and the XY table 18 While the workpiece W is positioned freely in the horizontal direction, the spindle 25 (tool 27) is moved up and down while rotating, so that the machining operation on the workpiece W is automatically executed.
[0022]
At this time, an operation panel 36 is provided on the outer wall surface of a splash cover (not shown) that covers the main body of the machine tool 11. As shown in FIG. 6, the operation panel 36 includes a display 37 that functions as a display unit and a key operation unit 38. The display on the display 37 is controlled by the control circuit 35, and a key operation signal from the key operation unit 38 is input to the control circuit 35.
[0023]
In this case, although illustration as a whole is omitted, as shown in FIG. 6, the key operation unit 38 has a “origin return” key 39 and a “cancel” key 40 used for an origin return instruction to be described later. A plurality of operation keys such as are provided and function as operation means. The key operation unit 38 is also provided with a plurality of manual operation keys 41 as manual operation means for manually operating each axis (inching operation).
[0024]
The control circuit 35 is configured to execute the origin return operation of each axis when necessary and when the origin return is instructed by the operation of the key operation section 38 of the operator. An axis control device is configured. Hereinafter, a part related to the return to origin of the index table 19 (B axis) will be described.
[0025]
FIG. 2 schematically shows the state of the index table 19 from the back side. As described above, the index table 19 is driven in the forward direction (“ It is freely rotated in the clockwise direction indicated by “+” and in the reverse direction (counterclockwise direction indicated by “−” in the drawing). For example, the position where the predetermined origin O of the index table 19 coincides with the upper part (0 degree) is set as the origin position.
[0026]
On the outer peripheral portion of the index table 19, a dog 42 is provided at a position slightly closer to the positive direction than the origin O, and on the fixed side, the dog 42 is positioned at a position slightly reverse to the 0 degree position. A dog switch 43 is provided which is turned on by. As the dog switch 43, for example, a limit switch with reliable operation and high durability is employed. As shown in FIG. 3, the operation signal of the dog switch 43 is input to the control circuit 35. In this case, the dog 42 turns on the dog switch 43 in a range of, for example, 2 to 3 degrees.
[0027]
As shown in FIG. 3, a non-volatile memory, in this case, a backup RAM 44 is connected to the control circuit 35, and the stop position (angular coordinates) of the index table 19 (B-axis motor 34) is connected to the backup RAM 44. ) Is always remembered.
[0028]
As will be described later in the description of the operation, when the “origin return” key 39 of the key operation unit 38 is turned on (normal operation), the control circuit 35 uses the software configuration to make the index table 19 Is rotated in the forward direction (+ direction) from the opposite side of the on operation position where the dog switch 43 is turned on, and the dog switch 43 is returned to the origin position when the dog switch 43 is turned on. Therefore, the control circuit 35 functions as an origin return control means.
[0029]
On the other hand, for example, when the “return to origin” key 39 is turned on (special operation) while the “release” key 40 of the key operation unit 38 is turned on, the control circuit 35 turns the dog switch 43 on and off. If the dog switch 43 is in the ON state (the index table 19 is in the ON operation position), the origin return operation of the index table 19 is performed as it is. If the dog switch 43 is in the OFF state, the origin return operation is performed. It is prohibited and error notification is performed.
[0030]
In the present embodiment, the control circuit 35 displays the on / off state of the dog switch 43 on the display 37 during the above-described home position return operation. As shown in FIG. 6, the display is performed not only on the B axis but also on each axis. Further, when the manual operation key 41 of the key operation unit 38 is operated, the control circuit 35 rotates each axis by a minute angle according to the operation. In this case, when the “+ B” key 41a of the manual operation keys 41 is operated, the index table 19 is rotated in the forward direction. When the “−B” key 41b is operated, the index table 19 is rotated. Is rotated in the reverse direction.
[0031]
Next, the operation of the above configuration will be described with reference to FIG. The flowchart in FIG. 1 shows a processing procedure executed by the control circuit 35 when performing the origin return operation of the index table 19. In other words, the operator turns on the “origin return” key 39 of the key operation unit 38 as described above in order to perform the origin return operation of the index table 19 in a normal state (No in step S1). ).
[0032]
Then, in the next step S2, it is determined whether or not the dog switch 43 is on (the index table 19 is in the on operation position), and if the dog switch 43 is on as shown in FIG. (Yes), the process proceeds to step S4 described later. On the other hand, when the dog switch 43 is not in the on state (No in step S2), in step S3, the index table 19 is located in a direction opposite to the on operation position (the state shown in FIG. 2A). The dog switch 43 is rotated in the positive direction at a high speed until the dog switch 43 is turned on.
[0033]
In this case, the stop position of the index table 19 is always stored in the backup RAM 44 and is not shown in detail in FIG. 1, but the position of the index table 19 stored in the backup RAM 44 is opposite to the ON operation position. If it is in the direction, the index table 19 is rotated at high speed in the forward direction as it is. On the other hand, if the position of the index table 19 stored in the backup RAM 44 is in the forward direction from the ON operation position (the position shown in FIG. 2B), the index table 19 is once rotated in the reverse direction to turn on. The position is returned to the position opposite to the operating position (the position shown in FIG. 2A), and is continuously rotated at a high speed in the forward direction.
[0034]
Thus, when the index table 19 is rotated in the forward direction at high speed and the dog switch 43 is turned on, the index table 19 is switched to low speed rotation and rotated at low speed until the dog switch 43 is turned off (step S4). When the dog switch 43 is turned off, it is rotated in the forward direction at a lower speed until the origin signal of the B-axis motor 34 is detected by the encoder (step S5). When the origin signal of the B-axis motor 34 is detected, a predetermined grid is obtained. The index table 19 is rotated and stopped by the shift amount (step S6).
[0035]
As a result, the origin of the index table 19 is returned. At this time, since the index table 19 is rotated in the forward direction at high speed until the dog switch 43 is turned on using the dog switch 43, the origin return can be performed reliably in a short time. Further, when the index table 19 is positioned in the forward direction relative to the ON operation position at the time of return to origin (the dog 42 is positioned in the forward direction side than the dog switch 43), the index table 19 is once returned in the reverse direction. The index table 19 does not stop at a position rotated 360 degrees from the original origin position, and the cable 33 can be prevented from being wound around the shaft 31 in advance.
[0036]
Thus, there may be a case where a mismatch occurs between the storage in the backup RAM 44 and the actual stop position of the index table 19. For example, when the contents of the backup RAM 44 are cleared by replacing the board at the time of repair, the power is turned off while the index table 19 is rotating, the index table 19 is rotated for some reason while the power is turned off, etc. It is. If there is a discrepancy between the storage in the backup RAM 44 and the actual stop position of the index table 19 as described above, the index table 19 is moved forward from the original origin position when the origin return operation is performed as described above. There is a risk that the cable 33 is wound around the shaft 31 and is disconnected at a position rotated 360 degrees.
[0037]
Therefore, when there is a possibility that a mismatch occurs between the storage in the backup RAM 44 and the actual stop position of the index table 19, the operator instructs the return to origin by a special operation of the key operation unit 38. (Yes in step S1). Specifically, the “return to origin” key 39 is turned on while the “release” key 40 is turned on. Then, in the next step S7, it is determined whether or not the dog switch 43 is on (the index table 19 is in the on operation position).
[0038]
If the dog switch 43 is turned on as shown in FIG. 2C (Yes in step S7), the process proceeds to step S4 as it is, and the origin return operation is performed as described above. Of course, when the origin is returned, the fact that the index table 19 is at the origin is stored in the backup RAM 44.
[0039]
On the other hand, if dog switch 43 is off (No in step S7), the origin return operation is not performed and error notification is performed (step S8). This error notification is performed, for example, by display on the display and sounding of a buzzer. At this time, the display 37 displays that the B-axis dog switch 43 is off.
[0040]
Therefore, if the stored contents of the backup RAM 44 are not reliable, the operator may instruct the origin return by a special operation, so that the dog switch 43 is in the on state, that is, the index table 19 is in the on operation position. Only when it can be detected (determined), the origin return operation is performed, and when the position of the index table 19 is unknown, the origin return operation is not performed and the cable 33 is wound around the shaft 31. Such a situation is prevented in advance. Further, the operator can easily know that the dog switch 43 is in the OFF state by looking at the display on the display 37.
[0041]
When the error notification is performed (step S8), the operator then checks the actual position of the index table 19 and the cable 33, and the “+ B” key 41a or “−B” of the key operation unit 38. The key 41b is operated, and the index table 19 is rotated in a direction in which the cable 33 is not entangled with the shaft 31 by manual operation from a remote location, and is brought to the ON operation position shown in FIG.
[0042]
At this time, when the index table 19 comes to the ON operation position, the display on the display 37 is switched to the fact that the dog switch 43 is ON, so that the key operation may be stopped at that time. After that, by instructing the return to origin by a special operation again, this time becomes Yes in step S7, and the return to origin of the index table 19 is performed.
[0043]
As described above, according to the present embodiment, when the origin return is instructed by a special operation, it is sure that no trouble such as disconnection occurs in the cable 33 connected to the index table 19 even if the origin return operation is performed. Only when the home position return operation is performed, in other cases, the home position return operation of the index table 19 is not performed and an error notification is made. As a result, even when the position of the index table 19 stored in the backup RAM 44 and the actual position do not coincide with each other, it is possible to prevent disconnection of the cable 33 and the like due to the return to origin operation. Can be obtained.
[0044]
In particular, in the present embodiment, since the index table 19 can be freely rotated by manual operation from a remote position by the manual operation key 41, the operator can move the index table 19 to a position where no error occurs, that is, the dog switch 43. Can be easily brought to a position where the is turned on. Furthermore, since the display 37 displays the on / off state of the dog switch 43, it is possible to obtain an advantage that the operator can easily know the on / off state of the dog switch 43.
[0045]
In the above embodiment, the present invention is applied to the origin return of the index table 19 (B axis). However, the present invention can be applied to other axes, and in a machine tool having a pallet table. It can also be applied to return to the origin of the pallet table. The present invention is not limited to the numerically controlled machine tool 1 and can be applied to return to the origin of the rotary shafts of various devices. In the description of the above embodiment, after the error notification, the manual operation key 41 is operated to move the index table 19 to the ON operation position. However, before the origin return is instructed by a special operation, the index table 19 It is also possible to move 19 to the ON operation position.
[0046]
In addition, for example, the cable 33 includes not only an electric wire but also an air hose and the like, and not only the backup RAM 44 but also other non-volatile memory can be used. Various modifications can be considered for the configuration of the (operation means), the display form of the display, and the like, and the present invention can be implemented with appropriate modifications without departing from the scope of the invention.
[0047]
【The invention's effect】
As apparent from the above description, according to the rotary shaft control device of the present invention, the origin return operation is performed using the dog switch, and the origin return is instructed by the special operation of the operation means. When the dog switch is on, the home position return operation is performed as it is. Even if the stored position of the rotating shaft and the actual position of the rotating shaft do not match, it is possible to prevent the disconnection of the cable or the like due to the origin returning operation of the rotating shaft. Play.
[Brief description of the drawings]
FIG. 1, showing an embodiment of the present invention, is a flowchart showing a processing procedure in an origin return operation
FIG. 2 is a diagram showing the relationship between the position of the index table and the position of the dog switch
FIG. 3 is a block diagram schematically showing the electrical configuration of a numerically controlled machine tool
FIG. 4 is a perspective view showing an external configuration of a main part of a main body of a numerical control machine tool.
FIG. 5 is a front view of an index table.
FIG. 6 is a front view of the operation panel.
FIG. 7 is a view corresponding to FIG. 2 showing a conventional example.
[Explanation of symbols]
In the drawing, 11 is a numerically controlled machine tool, 19 is an index table (rotating shaft), 31 is a shaft, 32 is a chuck mechanism, 33 is a cable, 34 is a B-axis motor, 35 is a control circuit (origin return control means), 37 Is a display (display means), 38 is a key operation unit (operation means), 39 is a "return to origin" key, 40 is a "release" key, 41 is a manual operation key (manual operation means), 42 is a dog, 43 is a dog switch 44 indicate backup RAMs.

Claims (3)

Operating means (38) for instructing the return of the origin of the rotary shaft (19) ;
A dog switch (43) that is turned on when the rotation shaft (19) is at a predetermined on-operation position closer to the reverse rotation direction than the origin position;
When the homing has been instructed by the operation means (38) operated, prior Symbol homing control means for returning said rotating shaft (19) to the origin position based on the operation of Dogusuitchi (43) and (35) A rotation axis control device comprising:
When the origin return is instructed by the normal operation of the operation means (38), the origin return control means (35) moves the rotating shaft (19) in the forward direction if the dog switch (43) is in an ON state. When the dog switch (43) is turned off while rotating at a low speed and the dog switch (43) is in an off state, the rotating shaft (19) is moved in the forward direction from the opposite direction side to the on operation position until the dog switch (43) is turned on. , And after the dog switch (43) is turned on, the rotating shaft (19) is rotated at a low speed in the forward direction to return to the origin position,
When an origin return is instructed by a special operation of the operating means (38) , if the dog switch (43) is in an ON state , the origin is returned by rotating the rotating shaft (19) at a low speed in the forward direction. The rotating shaft control device is configured to perform an operation and prohibit an origin return operation and perform an error notification if the dog switch (43) is in an OFF state. The rotating shaft control device according to claim 1, further comprising manual operation means (41) for freely rotating the rotating shaft (19) by a manual operation from a remote location. The rotary shaft control device according to claim 1 or 2, further comprising display means (37) for displaying an on / off state of the dog switch (43) .

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