JP3785285B2 - Stepping motor angle error correction device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stepping motor incorporated in a mounting head of an electronic component mounting apparatus (high-speed mounter), for example, and more particularly to an angle error correction apparatus for a stepping motor.
[0002]
[Prior art]
In the high-speed mounter, a plurality of mounting heads are mounted on the rotary table corresponding to a plurality of stop positions including an electronic component suction position and a mounting position. Each mounting head has a plurality of suction nozzles mounted on concentric circles, and a stepping motor having a rotary table side as a stator and a suction nozzle side as a rotor. Then, by appropriately rotating the stepping motor, one arbitrary suction nozzle to be used is selected from a plurality of suction nozzles, or the angle of the electronic component sucked by the suction nozzle is corrected (for example, JP-A-8-321698).
[0003]
[Problems to be solved by the invention]
By the way, since the angular accuracy of the stepping motor depends on the processing accuracy of the stator teeth, etc., when high angular accuracy is required for the above stepping motor, the stator processing accuracy of the stator is increased, or the stepping motor It is necessary to correct the step pulse of the corresponding motor driver (driving circuit) based on the individual angle error characteristics. The former method is more preferable because it increases the cost and has a limit in processing accuracy.
However, if the latter method is used, the angle error characteristic built into the motor driver is individual for each motor, so when replacing the mounting head (stepping motor) due to failure or maintenance, the corresponding motor driver must also be replaced. It is assumed that the work will be complicated. Moreover, mistakes, such as the stepping motor and motor driver which were changed not respond | corresponding, are assumed.
[0004]
The present invention provides an angle error correction device for a stepping motor that can improve the angle accuracy of a stepping motor without improving the machining accuracy, and can integrate the stepping motor and its angle error characteristics. Its purpose is to provide.
[0005]
[Means for Solving the Problems]
An angle error correction device for a stepping motor according to the present invention is mounted on a stepping motor, each of which has a specific stepping motor, and stores characteristic data of angle error that varies depending on the rotation angle of the stepping motor. Storage means, correction means for correcting the step pulse of the stepping motor based on the characteristic data stored in the storage means, and driving of the stepping motor based on the step pulse corrected by the correction means. And a control means.
[0006]
According to this configuration, the step pulse of the stepping motor is corrected based on the characteristic data of the angle error that changes depending on the rotation angle of the stepping motor stored in the storage means mounted on the stepping motor, and the corrected step pulse is corrected. Since the stepping motor drive is controlled by the stepping motor, the stepping motor and its angular error characteristic data can always be integrated, and the correction means and the control means can be constrained by the individual angle error characteristics of the motor. Of course, the angular accuracy of the stepping motor can be remarkably improved.
[0007]
In this case, the storage means is preferably a ROM chip.
[0008]
According to this configuration, the storage means can be easily mounted on the stepping motor.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electronic component mounting apparatus (high-speed mounter) equipped with an angle error correction device for a stepping motor according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view of the electronic component mounting apparatus, and FIG. 2 is a plan view thereof. As shown in both figures, the electronic component mounting apparatus 1 includes a supply system 3 for supplying an electronic component A and a mounting system 4 for mounting the electronic component A on a substrate B in parallel with each other with the apparatus main body 2 interposed therebetween. Is arranged. The apparatus main body 2 is provided with an index unit 11 serving as a main body of the drive system, a rotary table 12 connected thereto, and a plurality (12) of mounting heads 13 mounted on the outer peripheral portion of the rotary table 12. The rotary table 12 is intermittently rotated by the index unit 11 at an intermittent pitch corresponding to the number of mounting heads 13. When the rotary table 12 rotates intermittently, the suction nozzle 14 mounted on each mounting head 13 appropriately faces the supply system 3 and the mounting system 4 and sucks the electronic component A supplied from the supply system 3 and then rotates to the mounting system 4. It is transported and mounted on the substrate B introduced into the mounting system 4.
[0010]
The supply system 3 has a number of tape cassettes 21 corresponding to the type of electronic component A to be mounted on the substrate B, and the tape cassette 21 is provided on a supply table 23 slidably guided by a pair of guide rails 22 and 22. It is attached side by side and detachably. A ball screw 24 is screwed to the supply base 23 in the sliding direction. The supply base 23 is advanced and retracted by forward and reverse rotation of a feed motor 25 connected to one end of the ball screw 24, so that the mounting head 13 A desired tape cassette 21 is selectively brought to the suction position. Each tape cassette 21 is loaded with a carrier tape C loaded with electronic components A at a predetermined pitch in a state of being wound around a tape reel 26, and the electronic components A are unwound from the tape reel 26. The carrier tape C is sucked by the suction nozzle 14 as needed.
[0011]
The mounting system 4 includes an XY table 31 that moves the placed substrate B in the X-axis direction and the Y-axis direction, a carry-in conveyance path 32 and a carry-out conveyance path 33 that are arranged before and after the XY table 31, and a carry-in conveyance path 32. The upper substrate B is constituted by an XY table 31 and a substrate transfer device 34 for simultaneously transferring the substrate B on the XY table 31 to a carry-out conveyance path 33. The substrate B sent to the downstream end of the carry-in transport path 32 is transferred onto the XY table 31 by the substrate transfer device 34, and the substrate B on the XY table 31 on which the mounting of the electronic component A is completed is the same as this substrate. It is transferred to the carry-out conveyance path 33 by the transfer device 34. The board B introduced onto the XY table 31 is appropriately moved by the XY table 31 and corresponds to the electronic parts A sent one after another by the respective mounting heads 13 so that the component mounting part faces the mounting position. The electronic component A is mounted from each suction nozzle 14.
[0012]
The apparatus main body 2 has an index unit 11 that is the main body of a drive system on a support base 15. The index unit 11 intermittently rotates the rotary table 12 and is synchronized (interlocked) with the intermittent cycle of the rotary table 12. Then, various devices of the device main body 2 are operated.
[0013]
The rotary table 12 is fixed to a vertical shaft 16 that hangs down from the index unit 11 and rotates intermittently clockwise in plan view. Twelve mounting heads 13 are attached to the outer peripheral portion of the rotary table 12 via brackets 17 so as to be movable up and down at equal intervals in the circumferential direction. In this case, the intermittent rotation of the rotary table 12 is 12 intermittent cycles per rotation in accordance with the number of mounting heads 13, and each mounting head 13 revolving by this intermittent rotation is at 12 stop positions. Stop each one. At the 12 stop positions, in addition to the suction position for sucking and mounting the electronic component A, the position for imaging and position correction of the sucked electronic component A, and nozzle switching (replacement) in the mounting head 13 The position to perform is included.
[0014]
As shown in FIG. 3, each mounting head 13 rotates a nozzle holder 41 in which a plurality of (approximately 5) suction nozzles 14 arranged at equal intervals in the circumferential direction are mounted so as to be able to appear and retract, and the nozzle holder 41. A holder supporting member 42 attached to the bracket 17 on the apparatus main body 2 side and a passage member 43 attached to the upper surface of the nozzle holder 41 and having a vacuum passage 44 formed in the axial center are provided. . Between the nozzle holder 41 and the holder support member 42, a stepping motor 45 having the nozzle holder 41 on the rotor side and the holder support member 42 on the stator side is incorporated. The nozzle holder 41 rotates with respect to the member 42. That is, the plurality of suction nozzles 14 revolve around the axis of the nozzle holder 41.
[0015]
On the upper side of the holder support member 42, an end face cam 46 for projecting and retracting each suction nozzle 14 is disposed. An upper bearing 47 is disposed between the end cam 46 and the nozzle holder 41, and a lower bearing 48 is disposed between the holder support member 42 and the nozzle holder 41. That is, the nozzle holder 41 is rotatably supported by the holder support member 42 on the fixed side, and the end face cam 46 is rotatably supported by the nozzle holder 41.
[0016]
On the other hand, each suction nozzle 14 is configured such that the upper part is guided by a nozzle guide hole 51 formed in the passage member 43 and the lower part is guided by a roller guide 52 provided in the nozzle holder 41 so as to be movable up and down (can be moved up and down). ing. A support block 53 is screwed to the upper middle portion of the suction nozzle 14, and a roller follower 54 that is in rolling contact with the end face cam 46 is rotatably supported by the support block 53. Then, due to the forward / reverse rotation of the stepping motor 45, the one suction nozzle 14 to be used moves to a predetermined position and protrudes from the nozzle holder 41 by the cam action between the end face cam 46 and the roller follower 54, and is not used. Another suction nozzle 14 is immersed in the nozzle holder 41.
[0017]
As described above, the stepping motor 45 of the embodiment revolves the plurality of suction nozzles 14 mounted on the mounting head 13 and causes the arbitrary one suction nozzle 14 to protrude. Further, the electronic component A sucked by the suction nozzle 14 is slightly rotated for angle correction. On the other hand, the stepping motor 45 is driven via the motor driver 63 based on a command from the host computer 64 (see FIG. 5).
[0018]
By the way, when handling an extremely small electronic component A or when high mounting accuracy of the electronic component A to the substrate B is required, the stepping motor 45 is also required to have high angular accuracy. On the other hand, the stepping motor 45 has an angle error characteristic that individually affects the angle accuracy depending on the processing accuracy of the teeth of the stator. For example, in the angle error characteristic of the stepping motor 45 shown in FIG. 4, the error varies depending on the rotation angle, and the error tendency is different between the forward rotation and the reverse rotation. For this reason, in the present embodiment, the step pulse of the motor driver 63 is corrected based on the angle error characteristic of each stepping motor 45, and the driving of the stepping motor 45 is controlled by the corrected step pulse. .
[0019]
FIG. 5 shows a control system of the stepping motor 45. Each stepping motor 45 is equipped with a ROM chip 61 that stores error characteristic data that is an angular error characteristic of the stepping motor 45 (see FIG. 3). The ROM chip 61 is connected to the motor via an interface 62 on the motor side. The driver 63 is connected. On the other hand, each motor driver 63 is disposed on the upper side of the index unit 11 (see FIG. 1), and includes a CPU (correction means) 65 connected to the host computer 64, a ROM 66 for storing a driver program, and a correction. The RAM 67 is a work area for various data processing such as, a drive circuit (control means) 68 for driving the stepping motor 45, and a driver side interface 69 connected to the ROM chip 61.
[0020]
When power ON is input from the host computer 64 that controls the electronic component mounting apparatus 1 to the CPU 65 of the motor driver 63, the CPU 65 reads error characteristic data from the ROM chip 61 on the motor side into the RAM 67, and based on the error characteristic data. Thus, the step pulse of the drive circuit 68 is corrected. In this state, when a drive command is input from the host computer 64 to the CPU 65, the CPU 65 controls and drives the stepping motor 45 based on the corrected step pulse by driving the drive circuit 68. The ROM chip 61 can be freely attached to the stepping motor 45, but it is preferable that the ROM chip 61 be detachable.
[0021]
As described above, according to the present embodiment, since the step pulse of the drive circuit 68 is corrected by the error characteristic data of the ROM chip 61 mounted on the stepping motor 45, the processing accuracy of the stepping motor 45 is increased. In addition, the angle accuracy of the stepping motor 45 can be improved. Since the ROM chip 61 is mounted on the stepping motor 45, the stepping motor 45 and its angular error characteristics can be integrated at all times. When replacing the stepping motor 45, the individual angular error characteristics and the stepping motor 45 There is no error in the correspondence relationship. Furthermore, since the motor driver 63 reads the error characteristic data from the ROM chip 61 and corrects the step pulse, it is not necessary to replace the motor driver 63 corresponding to this when the stepping motor 45 is replaced.
[0022]
In the above embodiment, the case where the angle error correction device for the stepping motor of the present invention is applied to the stepping motor incorporated in the mounting head of the electronic component mounting device has been described. However, the angle error correction device of the present invention has high angular accuracy. Needless to say, the present invention is also applicable to stepping motors for other uses in which attachment / detachment or replacement is required.
[0023]
【The invention's effect】
As described above, the angle error correction device for a stepping motor according to the present invention is mounted on the stepping motor, each of the specific stepping motors mounted therein has characteristic data of angle error that varies depending on the rotation angle of the stepping motor. Storage means for storing, correction means for correcting the step pulse of the stepping motor based on the characteristic data stored in the storage means, and the stepping motor of the stepping motor based on the step pulse corrected by the correction means Control means for controlling the drive, and the step pulse of the stepping motor is corrected based on the characteristic data of the angle error of each motor stored in the storage means mounted on the stepping motor. The correction means and the control means can have a general-purpose configuration. Stepping motor may be replaced with the storage unit, you do not need to replace the corresponding correction means and the control means, of course, can be remarkably improved stepping motor each angular accuracy.
[Brief description of the drawings]
FIG. 1 is a side view of an electronic component mounting apparatus equipped with an angle error correction device for a stepping motor according to an embodiment of the present invention.
FIG. 2 is a plan view of the electronic component mounting apparatus according to the embodiment.
FIG. 3 is a cut side view of the mounting head of the embodiment.
FIG. 4 is a diagram illustrating an example of an angle error characteristic of a stepping motor.
FIG. 5 is a block diagram showing a control system of a stepping motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic component mounting apparatus 2 Mounting main body 13 Mounting head 41 Nozzle holder 42 Holder support member 45 Stepping motor 61 ROM chip 63 Motor driver 65 CPU
68 Drive circuit

Claims (2)

Mounted on the stepping motor, each of the mounted specific stepping motors individually has storage means for storing characteristic data of angle error that varies depending on the rotation angle of the stepping motor, and stored in the storage means A correction unit that corrects a step pulse of the stepping motor based on the characteristic data , and a control unit that controls the driving of the stepping motor based on the step pulse corrected by the correction unit. Stepping motor angle error correction device.   2. The angle error correction apparatus for a stepping motor according to claim 1, wherein the storage means is a ROM chip.

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