JP2009200094A - Electronic component mounter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric component mounter capable preventing a change in the control of rotation of a θ-axis of a nozzle by maintaining a belt so as to prevent a change in the relative rotation position of the belt for an original point of the θ-axis rotation of the nozzle even if characteristics of the belt change depending on the rotating position of the belt. <P>SOLUTION: The electronic component mounter is provided with a plurality of θ-axis drive mechanism each having a nozzle side pulley 10d freely rotating around the shaft in a θ-axis direction, a pulley 10c of a θ-axis motor for rotating the nozzle, and a belt 10e for transmitting the drive force of the θ-axis motor to the nozzle. The electronic component mounter is further provided with a photodetector 6 for detecting belt original point tabs 10f passing through the outside of U-shaped portions by detecting the shielding of an optical axis 7 parallel to an arrangement in which the U-shaped apexes of the belts 10e stretched on the pulleys 10c and forming the U-shape are arranged linearly each other. A rotation angle of the θ-axis of the nozzle is controlled by detecting the original point of a Z-phase of the θ-axis motor and detecting the original point tabs 10f of the belt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention has a nozzle that is rotatable about the axis in the θ-axis direction, a θ-axis motor for rotating the nozzle, and a belt for transmitting the driving force of the θ-axis motor to the nozzle. The present invention relates to an electronic component mounting apparatus that includes a plurality of θ-axis drive mechanisms, and sucks electronic components by an electronic component supply unit using the nozzles of these θ-axis drive mechanisms and mounts them on a board. By maintaining the rotation position of the belt relative to the position of the belt, even if there is a change in the characteristics of the belt depending on the rotation position of the belt, the control of the θ-axis rotation of the nozzle does not change. It is related with the electronic component mounting apparatus which can be performed.

  In the electronic component mounting apparatus, the posture of the electronic component attracted by the nozzle can be adjusted by rotating the nozzle around the axis as the θ axis. In general, in the θ-axis direction rotation, a pulley installed on a motor shaft and a pulley of a component mounting shaft are connected via a belt, and a driving force is transmitted via the belt to rotate. Further, the Z-phase in the θ-axis direction motor is used as the origin of the rotation axis in the θ-axis direction, and the rotation angle control is performed based on the origin.

  Here, as mentioned in Patent Document 1, the power transmission system using the timing belt has a feature that the degree of freedom in the layout design is large unlike the gear train and that the variation of one tooth hardly occurs. However, in the timing belt, the position of the core is not always the same in the thickness direction of the belt, and the belt may approach the belt surface or the back surface. The timing belt varies in characteristics (changes) in the circumferential direction. ) For this reason, there is a drawback that various rotational fluctuations such as rotational speed fluctuations and rotational angle fluctuations are likely to occur when the timing belt is driven to rotate.

  For this reason, in Patent Document 1, the origin mark of the timing belt is detected, the correction coefficient of the rotation fluctuation based on one rotation of the timing belt is measured in advance with this position as a reference, the correction based on this is performed, and the rotating body The driving accuracy is improved.

Japanese Patent Laying-Open No. 2003-15884 (FIG. 1)

  However, Patent Document 1 mainly targets an image reading apparatus, and does not particularly refer to an electronic component mounting apparatus. Further, in the electronic component mounting apparatus, the rotation angle control based on the origin of the Z phase as described above is performed, and the rotation angle control based on the origin of the timing belt as in Patent Document 1 is performed. Absent.

  FIG. 11 is a schematic diagram of a θ-axis drive mechanism in a conventional electronic component mounting apparatus.

  In this figure, a pulley 10c that can rotate integrally with a nozzle that adsorbs an electronic component is rotated by a θ-axis motor that rotates the pulley 10d via a toothed belt 10e or a pulley 10d. Further, if the circumferences of the pulley 10c and the pulley 10d are the same, their rotational positions correspond one-to-one, and the rotational position of the nozzle that rotates integrally with the pulley 10c is the θ axis with respect to the origin of the Z phase. This can be grasped based on the rotational position of the motor.

  Here, the toothed belt 10e has variations in characteristics in the circumferential direction as pointed out in Patent Document 1 described above. Further, when the circumferential length of the toothed belt 10e is an integral multiple of the circumferential lengths of the pulley 10c and the pulley 10d, the relative positional relationship between the rotational position of the toothed belt 10e and the rotational position of the θ-axis motor is There will be more than one.

  For example, in FIG. 11, it is assumed that the rotation position of the θ-axis motor that rotates integrally with the pulley 10c is at the origin of the Z phase, and as shown in the drawing, the position P1 on the toothed belt 10e is the position of the pulley 10c. It is in the lower part of the figure. Here, even when the rotational position of the θ-axis motor is at the origin of the Z-phase, depending on the rotation of the θ-axis motor, another position P2 on the toothed belt 10e may be placed at the position P1 in FIG. There may be a position P3 or the like. That is, the relative positional relationship between the rotational position of the θ-axis motor and the rotational position of the toothed belt 10e can change.

  For example, when the pulley 10c or the pulley 10d is manually rotated by one or more times when the power is shut off, when the power is turned on after that, the relative position between the rotational position of the toothed belt 10e and the rotational position of the θ-axis motor is determined. The positional relationship will change.

  If this relative positional relationship is always constant, the variation in the circumferential characteristics of the toothed belt 10e can be measured and corrected in advance according to the rotational position of the θ-axis motor. However, if this relative positional relationship changes, such correction becomes meaningless, and control of the rotational position of the nozzle is caused by the influence of variations in the circumferential characteristics of the toothed belt 10e. Accuracy will be reduced.

  In the electronic component mounting apparatus, the component mounting head is provided with a plurality of nozzles, and these nozzles are each provided with a θ-axis drive mechanism. In these θ-axis drive mechanisms, it is conceivable to individually provide means for detecting the belt origin as in Patent Document 1. However, the external dimensions and weight of the component mounting head increase, which adversely affects the control characteristics.

  The present invention has been made to solve the above-described conventional problems, and maintains the rotational position of the belt relative to the origin of the θ-axis rotation of the nozzle so that it does not change. It is an object of the present invention to provide an electronic component mounting apparatus that prevents a change in the control of the θ-axis rotation of a nozzle even when there is a change in characteristics.

  The present invention has a nozzle that is rotatable about the axis in the θ-axis direction, a θ-axis motor for rotating the nozzle, and a belt for transmitting the driving force of the θ-axis motor to the nozzle. In an electronic component mounting apparatus for mounting a plurality of θ-axis drive mechanisms on the board by adsorbing electronic components by the electronic component supply unit using the nozzles of these θ-axis drive mechanisms, each of the θ-axis motors is in a rotational position. These belts are provided with means for detecting the origin, and each of the belts is provided with a belt origin tab that protrudes outward, and is suspended in a pulley on the nozzle side or the θ-axis motor side, and is U-shaped. The U-shaped apexes of the belt are in a linear array, and the belt origin tab passing outside the U-shaped part is detected by detecting the shielding of the optical axis parallel to the array. A light detector for detecting the rotational position. The detection, and detection of the belt origin tabs, by which is adapted to control the rotation angle of θ axis of the nozzle is obtained by solving the above problems.

  According to the present invention, even if the relative positional relationship between the belt and the motor origin position changes, the belt and the motor origin position can always be adjusted to the same relationship by performing the origin return operation. For this reason, the accuracy correction result before product shipment can be maintained, and high-precision component mounting is possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of an electronic component mounting apparatus according to an embodiment to which the present invention is applied as viewed obliquely from above. FIG. 2 is a block diagram illustrating a hardware configuration related to control according to the present embodiment.

  In the electronic component mounting apparatus 20, the substrate 19 is disposed in the center, and the feeder 14 is disposed on the lower left side in the drawing. In the feeder 14, the nozzle 1 (see FIGS. 3 and 4 described later) of the mounting head 11 sucks the chip component 3 at a position 18. The mounting head 11 is provided with four nozzles 1 or four θ-axis driving mechanisms for rotating the nozzles 1 in the θ-axis direction in this embodiment in a series arrangement in the X-axis direction.

  The mounting head 11 is moved in the X-axis direction by the X-axis mechanism unit 12 to which the X-axis motor 21 is mounted, and in the Y-axis direction by the Y-axis mechanism unit 13 to which the Y-axis motor 22 is mounted. In addition, the Z-axis direction is moved in the Z-axis direction by the Z-axis mechanism portion in which the Z-axis motor 23 is mounted, and the θ-axis drive mechanism in which the θ-axis motor 24 is mounted. The Further, the nozzle 1 attached to the mounting head 11 sucks the chip component 3 by the vacuum mechanism 25 (FIG. 2).

  The mounting head 11 is provided with a laser recognition device 34 (FIG. 2) for measuring the cross-sectional length of the chip component 3 adsorbed by the nozzle 1 in a specific direction orthogonal to the θ axis.

  The electronic component mounting apparatus is provided with a CCD (Charge Coupled Device) camera 15 for photographing the chip component 3 adsorbed by the nozzle 1 from below, and a CCD camera 15a for photographing the reference mark of the substrate from above. .

  As shown in FIG. 2, these CCD cameras 15 and 15a are connected to an A / D (Analog to Digital) converter 27a built in an image recognition device 27 having a CPU (Central Processing Unit) 27c and a memory 27b. Yes. The image recognition device 27 is a vision camera that measures the dimensions and center position of the chip part 3 and the reference mark photographed by the CCD cameras 15 and 15a and measures the rotation angle of the chip part 3 around the θ axis. -The sensoring system (VCS) is configured. The image recognition device 27 receives an instruction from the controller 32 via the storage device 26.

  The controller 32 includes a CPU, a RAM (Random Access Memory), and a ROM (Read Only Memory), and is connected to a keyboard 28, a mouse 29, and a screen display device 30. The screen display device 30 is also connected to the image recognition device 27. The controller 32 is connected to the X-axis motor 21, Y-axis motor 22, Z-axis motor 23, θ-axis motor 24, vacuum mechanism 25, laser recognition device 34, and storage device 26.

  Next, FIG. 3 is a side view of the θ-axis drive mechanism of the electronic component mounting apparatus according to the present embodiment. FIG. 4 is a perspective view showing the rotation operation of the θ-axis drive mechanism. In these drawings, one of the four θ-axis drive mechanisms provided in the mounting head 11 in the present embodiment is shown.

  In FIG. 3, 10a is a θ-axis motor with a built-in motor encoder 10b, 10c is a driving pulley attached to the drive shaft of the θ-axis motor 10a, and 10d is attached to the actual drive shaft 11b of the suction nozzle 11a. The driven pulley 10e is a toothed belt that is stretched between the driving pulley 10c and the driven pulley 10d.

  A belt origin tab 10f is provided at one point on the toothed belt 10e so as to protrude outward. When the toothed belt 10e laid on the driving pulley 10c driven by the θ-axis motor 10a goes around the driving pulley 10c and the driven pulley 10d by the driving, the belt origin tab 10f goes around. Become. At this time, the belt origin tab 10f protruding to the outside does not interfere with the driving pulley 10c, the driven pulley 10d, and the like.

  In the present embodiment, the number of teeth of the toothed belt 10e is an integral multiple (K times) of the number of teeth of the driving pulley 10c and the driven pulley 10d. Further, the driving pulley 10c and the driven pulley 10d have the same size and the same number of teeth. Accordingly, it is determined in advance that the belt origin tab 10f makes one round when the θ-axis motor 10a rotates the number of times of the integral multiple K.

  FIG. 5 is a plan view of the θ-axis drive mechanism of this embodiment as viewed from above. 6 to 8 are partially enlarged views showing the θ-axis rotation operation in the θ-axis drive mechanism.

  In the present embodiment, the mounting head 11 is provided with four nozzles 1 or four θ-axis drive mechanisms that rotate the nozzles 1 in the θ-axis direction, and these are arranged in series in the left-right direction in FIGS. Yes.

  In each of the θ-axis drive mechanisms, the toothed belt 10e is U-shaped on one side of the drive pulley 10c. The U-shaped apexes are linearly arranged with respect to each other between the θ-axis drive mechanisms. In FIG. 5, for any toothed belt 10e, the belt origin tab 10f is located at the U-shaped apex on the drive pulley 10c side.

  The spot light 7 is irradiated from the projector 5 to the photodetector 6. The optical axis of the spot light 7 is parallel to the above-described linear array of U-shaped vertices. Therefore, if there is a belt origin tab 10f at or near the U-shaped apex, the spot light 7 is shielded by the belt origin tab 10f, and the belt origin is detected by the photodetector 6. The presence or absence of the shielding by the tab 10f can be detected.

  In each of the θ-axis drive mechanisms, the toothed belt 10e is also U-shaped in the driven pulley 10d, spanning the driven pulley 10d. The U-shaped apexes are linearly arranged with respect to each other between the θ-axis drive mechanisms.

  Therefore, on the driven pulley 10d side, the projector 5 and the photodetector 6 may be arranged so that the optical axis of the spot light 7 is parallel to the linear arrangement of the U-shaped vertices. .

  Here, in FIG. 6, the belt origin tab 10 f of the toothed belt 10 e does not block the optical axis of the spot light 7 in any of the θ-axis drive mechanisms in the photodetector 6. Therefore, the photodetector 6 does not detect the shielding of the optical axis of the spot light 7.

  The rotation of the toothed belt 10e at the left end advances in the direction of the arrow. In FIG. 7, this belt origin tab 10f is located at the apex of the driving pulley 10c side where the toothed belt 10e is U-shaped. The belt origin tab 10f shields the optical axis of the spot light 7. The shielding can be detected by the photodetector 6.

  Further, the rotation of the toothed belt 10e advances in the direction of the arrow. In FIG. 8, the belt origin tab 10f of the toothed belt 10e again blocks the optical axis of the spot light 7 in any θ-axis drive mechanism. Absent. Therefore, the photodetector 6 does not detect the shielding of the optical axis of the spot light 7.

  As described above, the photodetector 6 can not only detect the blocking of the optical axis 7 of the spot light by the belt origin tab 10f of the leftmost toothed belt 10e, but in FIG. It is possible to detect the blocking of the seven optical axes of the spot light by the belt origin tab 10f of the toothed belt 10e. As described above, for any toothed belt 10e, the photodetector 6 can detect the position of the belt origin tab 10f, and based on the detection, can grasp the absolute position of the toothed belt 10e. it can.

  As described above, in the present embodiment, the single light detector 6 can detect the blocking of the seven optical axes of the spot light by the belt origin tab 10f of any toothed belt 10e of the plurality of θ-axis drive mechanisms. it can. Therefore, the cost and installation space of the photodetector 6 can be suppressed.

  FIG. 10 is a time chart showing the origin return operation in the present embodiment.

  In this figure, the top stage is the Z-phase origin of the θ-axis motor 10a, and a pulse signal of the Z-phase origin is output from the motor encoder 10b every time the motor shaft of the θ-axis motor 10a makes one revolution. In FIG. 10, the pulse signal (P2) from time t1 to time t2 and the pulse signal from time t5 to time t6 (P1) are Z-phase origin pulse signals.

  In this figure, the middle stage is detection of the belt origin tab 10f by the photodetector 6, and detection of the origin of the toothed belt 10e. In FIG. 10, the pulse signal from time t3 to time t4 is the origin detection pulse signal.

  In this figure, the lowermost stage is the rotation operation of the θ-axis motor 10a based on the detection of the Z-phase origin of the θ-axis motor 10a and the detection of the origin of the toothed belt 10e, which is the origin return operation of this embodiment.

  In the embodiment, when performing the origin return operation, the θ-axis motor 10a is rotated until the origin of the toothed belt 10e is detected. In FIG. 10, the origin of the toothed belt 10e is detected by the photodetector 6 at time t3.

  When the origin of the toothed belt 10e is detected, next, the θ-axis motor 10a is reversely rotated until the Z-phase origin of the θ-axis motor 10a is detected and then stopped. Then, the stop position is a target origin for returning to the origin, and the return to origin is completed by the stop. In FIG. 10, at the time t2 ′, the Z-phase origin of the θ-axis motor 10a is detected by the motor encoder 10b.

  As described above, according to the present embodiment, the single light detector 6 detects the shielding of the seven optical axes of the spot light by the belt origin tab 10f of any toothed belt 10e of a plurality of θ-axis drive mechanisms. can do. For example, the origin return operation described with reference to FIG. 10 can be performed in any of a plurality of θ-axis drive mechanisms. After this home return operation, even if the motor encoder 10b is an inexpensive incremental encoder that can detect only the amount of displacement, the rotational position of the θ-axis motor 24, the θ-axis rotational position of the nozzle, and the toothed belt 10e. For any of these rotational positions, the absolute position can be grasped, and the rotation and positioning can be controlled.

  Here, a modification of the present embodiment will be described below.

  In the embodiment described above, the number of teeth of the toothed belt 10e is an integral multiple of the number of teeth of the driving pulley 10c and the driven pulley 10d. On the other hand, in the modification of the present embodiment, such an integral multiple condition is not added. However, in this modification, the relative relationship between the Z-phase origin of the θ-axis motor 10a and the origin of the toothed belt 10e when returning to the origin is specified as 45 ° offset by the rotation amount of the θ-axis motor 10a. The positional relationship is as follows.

  In this modification, the number of teeth of the toothed belt 10e is not an integral multiple of the number of teeth of the driving pulley 10c and the driven pulley 10d, but when the θ-axis motor 10a is rotated by a common multiple of these teeth, θ The relative relationship between the Z-phase origin of the shaft motor 10a and the origin of the toothed belt 10e is again the same. Therefore, by applying the present invention, the origin is returned by detecting the Z-phase origin of the θ-axis motor 10a and the origin of the toothed belt 10e, or the rotation angle of the θ-axis of the nozzle 1 is controlled. be able to.

  If the relative relationship between the Z-phase origin of the θ-axis motor 10a and the origin of the toothed belt 10e when returning to the origin is 45 ° offset by the rotation amount of the θ-axis motor 10a as described above, FIG. The origin return operation described by the above can be easily and reliably performed.

The perspective view which looked at the electronic component mounting apparatus of embodiment with which this invention was applied from diagonally upward The block diagram which shows the hardware constitutions of the control relation of the said embodiment Side view of the θ-axis drive mechanism of the electronic component mounting apparatus of the embodiment. The perspective view which shows rotation operation | movement of the said (theta) axis drive mechanism The top view which looked at the (theta) axis drive mechanism of the embodiment from the upper part First partially enlarged view showing the θ-axis rotation operation in the θ-axis drive mechanism. Second partially enlarged view showing the θ-axis rotation operation in the θ-axis drive mechanism. Third partially enlarged view showing the θ-axis rotation operation in the θ-axis drive mechanism. Time chart showing origin return operation in the embodiment Schematic diagram of the θ-axis drive mechanism in a conventional electronic component mounting device Schematic diagram of the θ-axis drive mechanism in a conventional electronic component mounting device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Nozzle 3 ... Chip component 10 ... (theta) axis drive mechanism 10a ... (theta) axis motor 10b ... Motor encoder 10c ... Drive side pulley 10d ... Driven side pulley 10e ... Toothed belt 10f ... Belt mark 10g ... Belt origin tab 11 ... Mounting head DESCRIPTION OF SYMBOLS 11a ... Adsorption nozzle 11b ... Actual drive shaft 12 ... X-axis mechanism part 13 ... Y-axis mechanism part 14 ... Feeder 15, 15a ... CCD camera 19 ... Substrate 21 ... X-axis motor 22 ... Y-axis motor 23 ... Z-axis motor 24 ... θ axis motor 25 ... Vacuum mechanism 26 ... Storage device 27 ... Image recognition device 27a ... A / D converter 27b ... Memory 27c ... CPU
28 ... Keyboard 29 ... Mouse 30 ... Screen display device 32 ... Controller 34 ... Laser recognition device

Claims (1)

A θ-axis drive mechanism having a nozzle that is rotatable about the axis in the θ-axis direction, a θ-axis motor for rotating the nozzle, and a belt for transmitting the driving force of the θ-axis motor to the nozzle In the electronic component mounting apparatus for adsorbing the electronic component at the electronic component supply unit by the nozzle of the θ-axis drive mechanism and mounting it on the substrate,
Each of the θ-axis motors includes means for detecting the rotational position origin,
Each of the belts has a belt origin tab protruding outward,
The U-shaped apexes of these belts, which are hung around the nozzle side or the θ-axis motor side pulley, are in a linear arrangement with each other,
A detector for detecting the belt origin tab passing through the outside of the U-shaped portion by detecting the shielding of the optical axis parallel to the array;
An electronic component mounting apparatus, wherein the rotation angle of the θ axis of the nozzle is controlled by detecting the rotation position origin and detecting the belt origin tab.

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