JP4314741B2 - Work entry confirmation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a workpiece loading confirmation device for confirming that a loader has properly loaded a workpiece with respect to a workpiece holding portion of a machine tool such as a lathe.
[0002]
[Prior art and problems to be solved by the invention]
When a workpiece is loaded into the lathe spindle chuck by the loader, the tip of the workpiece is carried to a position where it contacts the position of the workpiece seating surface of the spindle chuck, and the workpiece is gripped by a chuck claw provided on the spindle chuck. The loader is numerically controlled, and if there is an error in the coordinates by the control or there is an error in the equipment, the loader is chucked in a state of being lifted up without being in close contact with the workpiece seating surface. This causes a decrease in machining accuracy and a workpiece detachment.
[0003]
As a method for reliably seating a workpiece, there is a method of detecting the seating of a workpiece by load torque of the loader when the workpiece is loaded by the loader. However, when the work is pressed with the loader, the chuck claw may slip, and the correct value cannot be detected. In some cases, a cycle of positioning slightly before the seating position and pressing with a pusher may be used. However, in this case as well, a method for detecting the seating based on the load torque of the loader when the workpiece is loaded cannot be adopted.
[0004]
An object of the present invention is to provide a workpiece loading confirmation device having a simple configuration that can reliably check whether a workpiece has been correctly loaded by using an operation of a loader.
[0005]
[Means for Solving the Problems]
The configuration of the present invention will be described with reference to FIG. 1 corresponding to the embodiment. This workpiece loading confirmation device is a workpiece loading confirmation device for confirming that the loader (5) has properly loaded the workpiece (W) to the workpiece holding part (2) of the machine tool (1). end faces the loader (5) of the confirmation operation to perform the abutted operated chuck jaws (14a) of the loader chuck is part (14) in the loader (5) of the held by the holding portion (2) the work (W) The command means (21B), the work position detection means (31) for detecting the position of the work end face when applied, the position of the detected work (W) and the preset work (W) Work seat determination means (32) for determining whether the work (W) is held in close contact with the work holding portion (2) based on the dimension (H).
According to this configuration, after the work (W) is held by the loader (5) on the work holding unit (2), the loader (5) operates according to the command of the confirmation operation command means (21B), and the work (W) The chuck pawl (14a) of the loader (5) is applied to the end face. The workpiece position detecting means (31) detects the position of the end face of the workpiece (W) when this is applied. The detection of the end face position does not need to be obtained as position data, and it is only necessary to detect that the loader (5) is in a position where it hits the end face of the workpiece (W). The workpiece seating determination means (32) is configured such that the workpiece (W) is held in close contact with the workpiece holder (2) based on the workpiece position thus detected and the preset workpiece dimensions. It is determined whether or not.
In this way, since the loading confirmation is performed using the operation of the loader (5), it is not necessary to provide a special device for loading confirmation, and a simple configuration is sufficient. In addition, since the seating is confirmed after the workpiece (W) is held by the workpiece holder (2), not during loading, slipping during loading operation does not affect the detection error, and correct seating confirmation can be performed. . Moreover, since it detects after carrying in to the workpiece | work holding | maintenance part (2), seating confirmation can be performed irrespective of the control method of the carrying-in operation by the loader (5).
[0006]
In the present invention, the workpiece seating determination means (32) is provided at a position before the end face position of the workpiece (W) when it is held in close contact with the workpiece holder (2). When the chuck claw (14a) hits, it may be detected that the workpiece (W) is in a defective state in which the workpiece (W) is held in close contact with the workpiece holding portion (2).
In this way, by detecting that the chuck claw (14a) of the loader (5) has hit the front position, the work position detection means (31) can detect the position data as position data. Even if it is not detected, it may be possible to detect whether or not the front position is hit.
[0007]
In the present invention, the workpiece position detecting means (31) is configured to change the load torque of a servo motor (13) that moves the chuck claw (14a) of the loader (5) in the direction of application to the workpiece (W). The position may be detected.
When the chuck claw (14a) of the loader (5) hits the work (W), the load torque of the servo motor (13) that drives the loader (5) increases. Therefore, by detecting this load torque, that is, disturbance torque, it is detected that the loader (5) is in a position where it hits the end face of the workpiece (W). The load torque detecting means (30) is often provided in the loader (5) for various control of the loader, for example, for ensuring safety by detecting overload. Therefore, by detecting the workpiece position based on the change in the load torque, a dedicated device is not required, and the workpiece position detecting means can be simply configured.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a perspective view showing an example of a loader to which the present invention is applied and a machine tool as an external device. The machine tool 1 is a turret parallel two-axis lathe, and includes two sets of a work holding unit 2 composed of a spindle chuck and a turret tool post 3, and a work reversing device 4. The work reversing device 4 has two reversing device chucks 4a and 4b.
[0009]
The loader 5 is of a gantry type, and a lifting rod 9 is provided on a traveling table 7 traveling along the installation rail 6 so as to be movable up and down via a front / rear moving table 8. A loader head 10 is provided at the lower end of the lifting rod 9. It is. As shown in FIG. 3, the loader head 10 is provided with two loader chucks 14 in a forward posture and a downward posture facing the work holding unit 2, and the positions of the chucks 14 and 14 can be switched. Yes. The travel of the platform 7 (X-axis direction movement), the back-and-forth movement of the back-and-forth movement platform 8 (Z-axis direction movement), and the raising and lowering of the elevating rod 9 (Y-axis direction movement) It is done by driving.
[0010]
FIG. 1 is a block diagram of a conceptual configuration of a loader control device including the work carry-in confirmation device. The loader control device 20 is of a numerical control type by a computer, and controls the operation of the loader 5 by executing a loader program 21 by an arithmetic control unit 22 comprising a CPU, a memory and the like. The loader program 21 describes various sequence control commands such as an axis movement command for moving the loader head 10 to each position and a chuck command for opening and closing the loader chuck 14 of the loader head 10. The arithmetic control unit 22 decodes the loader program 21 and outputs a command corresponding to each movement command to the servo controllers 25 to 27 of each axis (X to Z axes), and sequence control such as a chuck command in the loader program 21. The command is transferred to each sequence control unit (not shown) such as the chuck opening / closing control unit 24. The chuck opening / closing control unit 24 is means for controlling the opening / closing of the loader chuck 14.
[0011]
The servo motors 11 to 13 for each axis are driven by the control of the servo controllers 25 to 27 for each axis. Each servo motor 11-13 has position detectors 11a-13a which consist of pulse coders etc., and servo controllers 25-27 perform position feedback control. Torque detection means 28 to 30 are provided in the drive systems of the servo motors 11 to 13 for the respective axes. These torque detection means 28-30 consist of ammeters etc. which detect the current supplied to each axis servomotor 11-13, for example. The detected torques of the torque detecting means 28 to 30 are also used for the control of the loader 5 other than the control for seating confirmation performed in the present invention. For example, the loader 5 is used to detect an overload that occurs when a collision occurs and stop the loader 5, or to teach a stop position of the loader 5.
[0012]
The workpiece carry-in confirmation apparatus of this embodiment is provided with the following confirmation operation command means 21B, workpiece position detection means 31, and workpiece seating determination means 32 in such a loader control device 20.
[0013]
The confirmation operation command means 21 </ b> B causes the loader 5 to perform an operation of applying a part of the loader 5 to the end surface of the work W held by the work holding unit 2 after the loader 5 carries the work W into the work holding unit 2. A means for giving a command to the arithmetic control unit 22. Some of the loader 5 is a chuck pawl 14a of Russia Dachakku 14. The confirmation operation command means 21B is provided as a part of the loader program 21. That is, the loader program 21 performs a loading operation program portion 21A for instructing a general loading / unloading operation of the rotor 5, such as an operation for loading the workpiece W into the workpiece holding unit 2, and a seating confirmation function as the above-described checking operation command means 21B. And a program part for
Confirmation operation command means 21B, as part of the instruction group abutted chuck claws 14a that are part of the loader 5 on the end face of the workpiece W held by the workpiece holding portion 2 has an axis movement command in the Z-axis direction ing. The Z-axis position that is the destination of this axis movement command is a position corresponding to the axial dimension of the workpiece W, and this Z-axis position is data of the dimension H of the workpiece W that is set in advance.
[0014]
The workpiece position detection means 31 detects the workpiece position based on a change in the load torque of the Z-axis servomotor 13 that moves the loader 5 in the direction of application to the workpiece W. The work position detection means 31 monitors the detection value of the torque detection means 30 for the Z-axis servomotor 13 and outputs a contact determination signal for determining that the loader 5 has hit the work end face when the set torque is reached. The set torque is set by an operator selecting an appropriate value based on data obtained in advance by a test operation or the like.
[0015]
Whether the workpiece seating determination means 32 is held in close contact with the workpiece holder 2 based on the end face position of the workpiece W detected by the workpiece position detection means 31 and the dimension H of the workpiece W set in advance. It is means for determining whether or not. Specifically, the workpiece seating determination unit 32 is configured to detect the workpiece position detection unit 31 until the commanded Z-axis position is reached when the loader 5 is moving toward the workpiece end surface in response to a command from the detection operation command unit 21B. When the hit is detected, it is determined that the seating is poor. Whether or not the commanded Z-axis position has been reached is recognized, for example, when the position deviation in the Z-axis servo controller 27 becomes zero. The work seating determination means 32 outputs an alarm signal or the like when it is determined that the seating is poor.
[0016]
The operation of the above configuration will be described. At the time of carry-in, the loader 5 moves the loader head 10 toward a predetermined position in the Z-axis direction toward the work holding unit 2 as indicated by a chain line in FIG. Thereafter, the work holding unit 2 closes the chuck claw 2a and holds the work W. After this holding, as shown in FIG. 4, an operation for confirming whether the workpiece W is correctly seated on the seating surface A of the workpiece holding portion 2 is performed.
This confirmation operation is performed as follows according to a command from the confirmation operation command means 21B. After loading the workpiece W, the loader 5 is retracted in the Z-axis direction, and the Y-axis position of the loader 5 is adjusted so that the predetermined chuck claw 14a of the loader chuck 14 is positioned at the center of the end surface of the workpiece W. change. Thereafter, the loader 5 is moved toward the workpiece end surface to a predetermined position Z _H , that is, to a position Z _H set as a Z-axis position corresponding to the workpiece dimension H.
[0017]
During this time, the workpiece position detection means 31 monitors the load torque of the Z-axis servomotor 13 with the detection value of the torque detection means 30. As shown in FIG. 4A, when the load torque exceeds the set torque while the loader 5 moves to the workpiece dimension corresponding position Z _H , if the workpiece position detecting means 31 does not detect the workpiece seat, The determination means 32 determines that the seat is properly seated.
As shown in FIG. 4 (B), when the workpiece W is held lifted from the seating surface A is a distance ΔZ just before position until the loader 5 reaches the workpiece dimensions corresponding position Z _H, the chuck of the loader 5 The claw 14a is pressed against the workpiece end surface. At this time, since the loader 5 tries to move to the command position, the load on the Z-axis servomotor 13 of the loader 5 increases. The work position detection means 31 monitors this increase in load, and outputs a work end face detection signal when the set torque is exceeded. Work sitting determination unit 32 is aware of whether it has reached the Z-axis position deviation (deviation of the feedback signal relative to a command position) of the servo controller 27 or the like to a target workpiece dimensions corresponding position Z _H, workpiece dimensions corresponding position until a Z _H to by receiving a detection signal of the work end surface, it is determined that the seating poor.
[0018]
Since the workpiece loading confirmation device performs loading confirmation using the operation of the loader 5 as described above, it is not necessary to provide a special device for loading confirmation, and a simple configuration is sufficient. Further, since the seating is confirmed after the workpiece W is held by the workpiece holding unit 2 instead of at the time of loading, slipping at the loading operation does not affect the detection error, and correct seating confirmation can be performed. Moreover, since it detects after carrying in to the workpiece | work holding | maintenance part 2, a seating confirmation can be performed irrespective of the control method of the carrying-in operation by the loader 5, etc. Further, since seating confirmation is performed after the workpiece W is held by the workpiece holding unit 2, seating confirmation can be performed even for irregularly shaped workpieces, and it is not necessary to perform setup change for seating confirmation depending on the workpiece shape. .
[0019]
Next, a description will be given of an experimental example in which it is verified whether or not the hit confirmation by the motor torque can be correctly performed. When pressing in the Z-axis direction with the Y-axis of the loader 5 fully extended, the loader 5 is far away from the position where it actually interferes, so there is a difference in the effect on the Z-axis motor 13 due to the rigidity of the loader 5. Get out. Therefore, a preliminary experiment for verification was performed.
As shown in FIG. 5, the experimental method is a method of confirming disturbance torque data by actually causing interference. (1) Lowering of the loader 5, (2) Z-axis in (toward the work holding unit 2 side) (3) DWLL (operation to delay entering the next operation for a predetermined time), (4) Z-axis out, and (5) lift of the loader 5 are performed. The positioning coordinate of the Z-axis in (2) above was shifted in the minus direction in 0.1 mm increments from the position of interference between the loader 5 and the work holding part 2, and the data was taken 5 times each time and plotted on a graph. FIG. 5B shows the loader program for reference. Data was collected by changing the value of the target position * in the Z-axis in operation command in the figure by 0.1 mm between −88.62 and −89.62.
[0020]
As a result of this experiment, data obtained in FIG. 6 was obtained. As can be seen from this result, the value of the disturbance torque is clearly different in increments of 0.1 mm. From this, it can be determined that the method of confirming the hit with the disturbance torque value is sufficiently practical if the accuracy of the 0.1 mm range is sufficient. When 1 mm or more was pressed, a servo alarm state occurred due to a predetermined safety function of the servo controller 27. Therefore, in the model used for the experiment, the usable range is considered to be 0.1 to 0.9. If the loader model is different, the above values are different.
[0021]
【The invention's effect】
A workpiece loading confirmation device according to the present invention is a workpiece loading confirmation device for confirming that a loader has properly loaded a workpiece with respect to a workpiece holding portion of a machine tool, and is an end face of the workpiece held by the workpiece holding portion. Confirmation operation command means for causing the loader to apply the chuck claw of the loader chuck of the loader to the loader, workpiece position detection means for detecting the position of the workpiece end surface when the load is applied, and the detected workpiece position and Since it is provided with a workpiece seating judging means for judging whether or not the workpiece is held in close contact with the workpiece holding portion based on a preset workpiece dimension, the loader operation is used. Therefore, it can be confirmed with reliability whether or not the workpiece has been correctly loaded, and it can be confirmed with a simple configuration.
The workpiece seating determination means is configured such that when the chuck claw of the loader hits a position before the end surface position of the workpiece when the workpiece is held in close contact with the workpiece holding portion, the workpiece is in contact with the workpiece holding portion. In the case of detecting a defective state that is held without being in close contact, confirmation can be performed with simple control.
When the workpiece position detection means detects the workpiece position by changing the load torque of a servo motor that moves the chuck claw of the loader in the direction of application to the workpiece, a special mechanism is used for the detection of hitting. Can be done without.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a conceptual configuration of a loader control device provided with a work loading confirmation device according to an embodiment of the present invention.
FIG. 2 is a perspective view of a machine tool and a loader using the workpiece carry-in confirmation apparatus.
FIG. 3 is a cutaway side view of the loader.
FIG. 4 is an explanatory diagram of a confirmation operation by the workpiece carry-in confirmation apparatus.
FIG. 5A is an explanatory diagram showing an experiment example for verification of the work carry-in confirmation apparatus, and FIG. 5B is a loader program for the experiment.
FIG. 6 is an explanatory diagram of data obtained by the experiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Machine apparatus 2 ... Work holding part 3 ... Tool post 5 ... Loader 6 ... Installation rail 7 ... Traveling base 8 ... Front / back movement base 9 ... Lifting rod 10 ... Loader heads 11-13 ... Servo motor 14 ... Loader chuck 20 ... Loader Control device 21 ... loader program 21B ... confirming operation command means 22 ... calculation controller 27 ... servo controller 30 ... torque detection means 31 ... work position detection means 32 ... work seating determination means H ... work size W ... work

Claims (3)

A workpiece loading confirmation device for confirming that a loader has properly loaded a workpiece into a workpiece holding portion of a machine tool, wherein a chuck claw of a loader chuck of the loader is attached to an end surface of the workpiece held by the workpiece holding portion. Confirmation operation command means for causing the loader to perform the abutting operation, a workpiece position detecting means for detecting the position of the workpiece end surface when the abutting operation is performed, and the detected workpiece position and preset workpiece dimensions. A workpiece loading confirmation device comprising: a workpiece seating determination unit that determines whether or not the workpiece is held in close contact with the workpiece holding unit. The workpiece seating determination means is configured such that when the chuck claw of the loader hits at a position closer to the end surface position of the workpiece when the workpiece is held in close contact with the workpiece holding portion, the workpiece is against the workpiece holding portion. 2. A workpiece loading confirmation device according to claim 1, wherein the workpiece loading confirmation device detects a defective state held without being in close contact. 3. The workpiece loading according to claim 1, wherein the workpiece position detecting means detects the workpiece position based on a change in load torque of a servo motor that moves the chuck claw of the loader in a direction in which the chuck is applied to the workpiece. Confirmation device.

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