JPH08204392A - Electronic parts mounting apparatus - Google Patents

Abstract

PURPOSE: To eliminate the influence of the backlash and reduce the indexing time of the rotation angle of a driven gear fixed to an index table by transmitting the rotation of a torque control motor via transmission gear ears to the internal tooth of the gear to exert the torque against the driving direction of a drive motor to rotate the gear. CONSTITUTION: A gear 107 fixed to an index table to rotate integratedly has an external tooth 108 meshed with a gear 135 coupled with a drive motor to intermittently rotate it, while an internal tooth 109 of the gear 107 is meshed with a gear 154 rotatable integratedly with an output rotary shaft of a torque control motor so as to transmit its torque against the intermittent rotation drive. Owing to the function of this torque control mechanism, the dispersion of the stop position of a mounting head in its intermittent rotation is reduced against the effect of the backlash caused by the meshing of the gear 135 with the external tooth 108 of the gear 107, thereby improving the accuracy of the stop position of the head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component mounting apparatus capable of mounting various kinds of chip-shaped electronic components on a substrate, and more particularly, a plurality of mounting heads are arranged at the peripheral portion of an index table and an electric motor is provided. The present invention relates to an electronic component mounting apparatus suitable for a so-called sequence method in which electronic components are picked up and transferred from a fixedly arranged supply unit in the mounting sequence with intermittent rotation of an index table driven via a gear.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Publication No.
In No. 63840, a rotor that corresponds to an index table and rotates intermittently, a mounting head of a plurality of electronic components equipped at a constant interval along the entire circumference on a concentric circle of the rotor, and a component suction nozzle of each of these mounting heads are provided. The placement table of the component mounting board, which is located at a fixed position around the circumference of the rotor and is located below the locus that moves by the intermittent rotation of the rotor, and the component suction nozzles of each mounting head move by the intermittent rotation of the rotor. Each of the sending parts of the electronic component is fixed to the center of rotation of the rotor by aligning the parts below the locus of And a supply device for electronic components installed in a line in a radial direction, and each mounting head supplies the electronic device while moving in a supply region of a plurality of arranged electronic components of the supply device. Assemble into a mechanism that receives electronic components from any one of the predetermined placement parts, carries them on a substrate placement table installed at a position away from the electronic component supply area, and sequentially mounts the electronic components on the substrate. In the automatic mounter for chip parts, the spindle of the rotor is linked with a drive motor through a gear housed in a gear box, and basically the drive motor is used as a drive source. An electronic component mounting apparatus configured to rotate a rotor intermittently in a predetermined cycle is shown.

In Japanese Patent Laid-Open No. 19440/1989,
In an electronic component mounting apparatus having an index table having a plurality of mounting heads and rotated intermittently, a chip type electronic component is adsorbed to the mounting head from a component supply apparatus and mounted on a printed circuit board. An electronic component mounting apparatus is shown in which a rotor of an angular positioning motor is directly connected to a rotary shaft of a table coaxially therewith.

[0004]

By the way, as described above, the spindle of the rotor corresponding to the index table is linked with the drive motor through the gear (gear), and the drive motor is the NC of the electronic component mounting apparatus. A servo motor that is drive-controlled by a control device, wherein the rotation of the servo motor is drive-controlled to a predetermined angle to determine the rotation angle of the index table, and a large number of mounting heads arranged on the peripheral portion of the index table. In the configuration in which each of them is sequentially positioned on the predetermined feeding device or the mounting table of the printed circuit board, the gear that rotates integrally with the output rotation shaft of the servo motor and the gear that is fixed to the index table or fitted to the support shaft are integrated. A speed reduction mechanism that meshes with a rotating gear. As a result, the index table in which a large number of mounting heads are arranged on the periphery becomes large and heavy, but the index of the rotation angle becomes finer and the reduction ratio becomes larger. Side load inertia is reduced. However, backlash is required for meshing gears, and the reduction mechanism using gears cannot avoid the presence of backlash.

It is conceivable that the output rotary shaft of the servo motor is directly connected to the rotary shaft of the index table in which a large number of mounting heads are arranged. However, as described above, the reason is that the index table is large and heavy or the rotary angle is finely indexed. Is difficult. Therefore, the backlash amount by the gear is appropriately set by using the speed reduction mechanism by the gear, and the influence of the backlash is removed by devising a new structure, and the accuracy of indexing and repeating the rotation angle is improved. Also, the drive control of the servo motor by the NC control device is performed by a feedback loop depending on whether a detector is provided on the output rotation shaft of the servo motor to obtain a feedback signal or whether the angular position of the index table is directly detected to obtain a feedback signal. Although the range included is different, mechanical resonance due to backlash, torsional rigidity, mass of moving parts, etc. will affect the loop, and the stability will deteriorate as the gain of the servo amplifier in the feedback loop is increased, Therefore, by devising a new configuration to eliminate the influence of backlash, it is possible to set a higher gain, shorten the rotation angle indexing time, and reduce vibration.

[0006]

In order to achieve the above object, according to the present invention, a plurality of mounting heads having component suction nozzles are arranged at the periphery of an index table which rotates intermittently, and the index is provided. At the position where the mounting head stops with intermittent rotation of the table, the component suction unit of the mounting head arranges a supply device for picking up electronic components, and the component suction nozzle of the mounting head is moved up and down. In an electronic component mounting apparatus having a mounting work position for mounting an electronic component picked up by the component suction nozzle on a positioned printed circuit board surface, the driven gear is fixed to the index table by sharing a rotation center, The driven gear is engaged with the drive gear coupled to the drive motor for intermittent rotation drive, and An electronic component mounting apparatus characterized by comprising torque control means for transmitting a torque opposing said drive gear is provided.

Further, according to the present invention, in the above, the torque control means engages the driven gear with a transmission gear that rotates integrally with the output rotation shaft of the torque control motor,
There is provided an electronic component mounting device configured to rotationally drive the torque control motor in a direction opposite to the intermittent rotational drive of the drive motor to transmit a counter torque to the driven gear.

[0008]

In the electronic component mounting apparatus of the present invention, the intermittent rotation of the index table is rotationally driven by the drive motor, and the rotation of the drive motor is transmitted to the external teeth of the driven gear fixed to the index table via the drive gear. The rotation of the torque control motor of the torque control mechanism is transmitted to the internal teeth of the driven gear fixed to the index table via the transmission gear, and the drive motor exerts a torque that opposes the direction in which the driven gear is rotationally driven. The torque against which the torque control motor opposes is set to such an extent that the rotational drive of the drive motor is not reversed, and the torque is controlled so as to act or not act in accordance with the rotational drive of the drive motor. It is applied when the drive motor slows down or maintains a stopped state, and the back teeth of the driven gear and the back gear of the driven gear are biased to a certain side so that the engagement between the outer tooth and the drive gear is always on a certain tooth surface. Keep in contact.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an electronic component mounting apparatus according to the present invention will be described below with reference to the drawings.

FIG. 9 shows an outline of the entire mounting apparatus as an example of an electronic component mounting apparatus for carrying out the present invention. 7 and 8 show an overview, 1 is an index table, and 2 is a mounting head. An XY table 3 is an X table 31 that is movable in the X direction, which is a substrate loading / unloading direction with respect to the main frame 4, and an X table 31 that is parallel to the substrate transport surface and perpendicular to the X direction with respect to the X table 31. Y table 32 that can move in Y direction
The Y table 32 is movable with respect to the main body frame 4 in the XY directions by combining with the movement of the X table 31. Board support pin plate 32 is provided on the Y table 32.
1, a conveyance guide base 322, a back side guide 323 mounted on the conveyance guide base 322, a front side guide 324, and a reference pin 325 and a quasi-reference pin 326 to be inserted into a positioning hole of the board.
Have.

Reference numeral 5 is a board carry-in conveyor, and 6 is a board carry-out conveyor. The printed board sent from the previous step is taken in from the board carry-in conveyor 5 and conveyed, and then X-
When the Y table 3 is moved, the both sides are supported and conveyed by the back side guide 323 and the front side guide 324 which are aligned with the substrate carry-in conveyor 5 and are continuous, and when they are blocked by the stopper at a predetermined position, the reference pin 325 and the quasi-reference pin 326 rises and fits into the positioning hole of the printed circuit board and is fixed to the Y table 32. Reference numeral 7 denotes a component supply unit having a plurality of electronic component supply devices. A plurality of mounting heads 2 are attached to the peripheral portion of the index table 1 at equal intervals. Each of the mounting heads 2 is picked up from above the component supply unit 7 that picks up electronic components as the index table 1 rotates. The printed circuit board on which the electronic component is mounted is fixed on the Y table 32, passes through the XY table 3, and then circulates over the component supply unit 7. The distance between the board carry-in conveyor 5, the distance between the back guide 323 and the front guide 324, and the distance between the board carry-out conveyor 6 are set in advance according to the width of the printed circuit board to be conveyed. Further, as a means for transporting, for example, a structure of an endless belt that supports and transports both sides of a printed circuit board is known. As another configuration, it is also known that a member that linearly reciprocates in the X direction is provided with a claw that pushes the rear end of the printed circuit board, works to push in the transport direction, and retracts on the return side. Reference numeral 8 denotes an operation panel. The component suction nozzles 21 of the mounting head 2 are respectively movable up and down with respect to the index table 1, and as the index table 1 rotates, the component suction nozzles 2 of the predetermined mounting head 2 are moved.
When 1 reaches a predetermined supply device, it moves up and down to adsorb and hold a predetermined electronic component. The mounting heads 2 each holding a predetermined electronic component reach the mounting work position M on the XY table 3 one after another as the index table 1 rotates. The printed circuit board fixed to the Y table 32 moves in the XY direction in combination with the movement of the X table 31, and the position on the printed circuit board surface where a predetermined electronic component is to be mounted is positioned at the mounting work position M. . The component suction nozzle of the mounting head 2 holding the electronic component moves up and down at the mounting work position M to mount the electronic component on the printed circuit board surface. The electronic component is held by an adhesive applied on the printed circuit board surface in advance. The printed circuit board on which all predetermined electronic components are mounted is sent to the board unloading conveyor 6 and sent to the subsequent process.

FIG. 1 is a plan view showing the main structure of the rotary drive mechanism. FIG. 2 is a cross-sectional view of the index table 1 and a rotary drive mechanism that rotationally drives the index table 1, viewed from the side, showing the base 10 fixed to the upper surface 41 of the main body stand 4.
Assembled to zero. The hollow shaft 101 has two steps of the base 100, and each is fixed to the upper step surface 113 of the mounting surface parallel to the upper surface of the main body stand 4 through the mounting plate 102 perpendicularly to the mounting surface. 4 is also perpendicular to the upper surface 41. The upper end of the shaft 101 is a support plate 103.
The support plate 103 is supported by the main body stand 4 via other members (not shown). A cylindrical body 106 with a collar is attached to the outer diameter portion of the bearing 104 and the bearing 105 fitted to the shaft 101.
The inner diameter portion is fitted and the outer diameter portion is rotatably supported concentrically with the shaft 101. The index table 1 has a disk shape, and has a hole 111 perpendicular to the disk surface at the center of the index table 1, which is fitted to the outer diameter portion of the flanged cylindrical body 106 and fixed by bolting to the flange portion. The index table 1 is rotatable about a shaft 101 with its disc surface parallel to the upper surface 41 of the main body stand 4. Reference numeral 107 denotes a ring-shaped gear. The outer teeth of the gear 107 are machined with outer teeth 108 of the gear, and the inner teeth 109 are concentric with the outer diameter of the gear 107, and the thickness direction of the gear is shared. A hole 110 having a larger diameter than the gear portion is machined. Provide a boss on the bottom side of the index table 1 to make a trip and make a hole 1
A boss outer diameter portion 112 concentric with 11 is provided, the hole 110 of the ring-shaped gear 107 is fitted, and the index table 1 and the gear 107 are bolted and fixed. Gear 1
07 is integrated with the index table 1 around the shaft 101 so that the outer teeth 108 and the inner teeth 109 are concentrically rotatable.

The height of the lower step surface 114 of the mounting surface parallel to the upper surface 41 of the main body stand 4 from the upper surface 41 of the main body stand 4 and the mounting surface 121 having the same height as the upper surface 41 of the main body stand 4 are arranged. The auxiliary base 120 that is provided is fixed to the upper surface 41 of the main body stand 4. The flanged cylindrical body 122 has the flange surface 123 on the lower step surface 114 of the base 100 and the auxiliary base 1.
4 bolts 13 that are passed over both mounting surfaces 121 of 20
Since the lower surface 114 and the mounting surface 121, which are fixed by 8, are at the same height with respect to the upper surface 41 of the main body stand 4, the flange surface 123 is parallel to the upper surface 41 of the main body stand 4. The lower end surface 124 of the flanged cylindrical body 122 is the flange surface 1
Servo motor 129 which is parallel to 23 and is a drive motor
Bolt the mounting flange of to fix. At the lower end of the inner diameter hole 125 of the flanged cylindrical body 122, a stepped hole having a slightly larger inner diameter is provided, and the outer diameter portion of the mounting boss of the servomotor 129 is fitted to the flanged cylindrical body 122.
It is securely positioned and fixed to. The output rotation shaft 126 of the servo motor 129 projects into the internal space of the inner diameter hole 125.

The lower end surface 131 of the gear block 130 is fixed to the upper end surface of the flanged cylindrical body 122 by bolting, and the upper end surface of the flanged cylindrical body 122 is parallel to the flange surface 123 and is the upper surface of the main frame 4. It will be parallel to 41. The inside of the gear block 130 is a two-stage space, and the lower space 132 is continuous with the upper opening of the internal hole 125 of the flanged cylindrical body 122 to form a space. Part of the upper space 133 is a notch opening on the side surface of the gear block 130, and the gear 135 of the geared shaft 134 to be assembled inside the upper space 133 meshes with the external teeth 108 of the gear 107 through this notch opening. It becomes a place. There is an intermediate wall between the lower space 132 and the upper space 133, and an upper wall above the upper space 133. Through the gear block 130 perpendicularly to the lower end surface 131, the geared shaft 1
In order to mount 34, the bearing 136
Is fitted and mounted, and the bearing 137 is fitted and fitted into the hole formed in the upper wall so as to be concentric. In order to fix the thrust direction of the bearing 136, the hole formed in the intermediate wall of the gear block 130 has a two-step diameter to form a flange portion on the upper portion, and the bearing 13
When 6 is incorporated and then the lid is bolted to the lower surface to attach it, the thrust direction of the bearing 136 is fixed by the flange portion and the lid. The hole drilled in the upper wall is straight. Shaft with gear 1
34, the gear 135 has the largest diameter, followed by the lower diameter portion to be fitted with the bearing 136, and the lower diameter portion next to the output rotary shaft 126 of the servomotor 129. The upper end portion that has the same diameter and fits with the bearing 137 is the smallest diameter portion. The method of stopping the bearing 137 in the thrust direction is to attach the pressing lid from the upper wall surface of the gear block 130 by bolting the shaft with the gear. The thrust direction is fixed with 134 and the pressing lid.

The output rotary shaft 126 of the servomotor 129 and the lower diameter portion of the geared shaft 134 are coaxially connected with each other by a rigid coupling. The rigid coupling is composed of a cylindrical body 127 and two compression bushes 128. . The cylindrical body 127 has a hole for coaxially fitting the lowermost diameter of the gear shaft 134 and the output rotary shaft 126 in the inner diameter portion, and a hole for fitting the bush outer diameter portion of the compression bush 128 with a diameter larger than the hole at both ends. It has a large outer diameter portion. The inner diameter of the hole of the compression bushing 128 is the diameter of the lowermost part of the gear shaft 134 and the diameter of fitting with the output rotary shaft 126. The lowermost diameter of the gear shaft 134 and the output rotary shaft 126 are symmetrically arranged vertically.
And one by one, and with the lowermost diameter of the geared shaft 134 and the output rotary shaft 126 fitted in the inner diameter portion of the cylindrical body 127, holes formed in steps from both ends of the cylindrical body 127. When the outer diameter portion of the bush is inserted into both ends of the bush and the pressure medium (liquid) sealed in the compression bush 128 is tightened by pressurizing the pressure bolt in this state, the outer diameter portion and the inner diameter portion of the bush are respectively separated. The outer diameter increases and the inner diameter decreases, so that the gear shaft 134 and the output rotation shaft are fixed and coaxially connected to each other via the cylindrical body 127.

The index table 1 is the hollow shaft 1 described above.
Rotate around 01. FIG. 1 is a phantom line showing a state in which the mounting heads 2 are arranged at equal angular intervals on the peripheral portion of the index table 1 with the same circumference. FIG. 1 is a plan view showing the main configuration of the rotary drive mechanism of the index table 1. The plan view shows the outer teeth 10 of the ring-shaped gear 107 without the index table 1 being drawn.
8 and the gear 135 of the geared shaft 134 mesh with each other, and the gear 1
The meshing arrangement of the inner teeth 109 of No. 07 and the gear 154 of the torque control mechanism is shown.

On the mounting surface 121 of the auxiliary base 120, the receiving block 140 of the position adjusting bolt 143 of the flanged cylindrical body 122 is bolted and fixed. Receiving block 1
Reference numeral 40 denotes a U-shaped groove 141, and a shaft portion 142 obtained by extending the position adjusting bolt 143 is fitted therein. The shaft portion 142 sandwiches the receiving block 140 in the thickness direction thereof.
2 is provided with a bolt head 144 integrated with the shaft portion 142 and a ring 145 fitted to the shaft portion 142. The ring 145 is fixed to the shaft portion 142 by a fastening member such as a spring key.
The position adjusting bolt 143 restrains the thrust direction of the position adjusting bolt 143 with respect to the receiving block 140. The tip of the position adjusting bolt 143 is screwed into a screw hole 139 formed in the flange side surface of the flanged cylindrical body 122. Servo motor 12
The mechanism from 9 to the gear 135 is a cylindrical body 122 with a flange.
It is integrated with the base 1 by loosening the four bolts 138.
00 lower step surface 114 and auxiliary base 120 mounting surface 12
It is possible to move within the range of the allowance of the hole through which the bolt 138 drilled in the flange on 1 is inserted. When the four bolts 138 are appropriately loosened while the external teeth 108 and the gear 135 are meshed with each other, and then the bolt head 144 of the position adjusting bolt 143 is turned by applying a spanner or the like to the receiving block 140 to form a cylindrical cylinder with a flange. The body 122 can be moved so that the external teeth 1
It is possible to change the meshing gap between the gear 08 and the gear 135, in other words, the backlash between the external teeth 108 and the gear 135 can be adjusted.
While adjusting the backlash between the outer teeth 108 and the gear 135 coupled to the output rotation shaft 126 of the servomotor 129, 4
The backlash amount G can be properly set by tightening the individual bolts 138.

A part of the gear 107 is cut away in FIG. 1 to show the torque control mechanism. In FIG. 2, the position is the back side and cannot be seen. FIG. 3 is a cross-sectional view of the portion of the torque control mechanism as seen from the side. An L-shaped fixture 150 is attached to the side surface of the base 100 so that the upper surface of the fixture 150 is parallel to the upper surface 41 of the main frame 4 and bolted. Then install. The servo motor 160, which is a torque control motor, is installed in the hole machined in the center of the mounting plate 151.
The outer diameter portion of the mounting boss is fitted, and the flange portion of the servo motor 160 is fixed to the mounting plate 151 with four bolts 152. A vertical hole is provided on the upper surface of the fixture 150, and the diameter of the hole is set to a size that allows the outer diameter of the main body of the servomotor 160 to pass therethrough.
When the main body of the servo motor 160 fixed to 1 is passed from above, the mounting plate 151 is placed on the upper surface of the mounting fixture 150 with the servo motor 160 suspended, and in this state, from the side of the hole provided in the mounting fixture 150. The two bolts 153 are screwed into the screw holes provided in the mounting plate 151 and bolted. When the bolt 153 is loosened, the mounting plate 151 moves while being mounted on the upper surface of the mounting member 150 within a margin of the hole provided in the mounting member 150, and the servo motor 160 fixed to the mounting plate 151 also moves integrally. As a result, the backlash between the internal teeth 109 and the gear 154 that is fitted to the output rotary shaft 155 of the servo motor 160 and integrally rotates can be adjusted. Thus, the backlash between the internal teeth 109 and the gear 154 can be reduced. By tightening the two bolts 153 while adjusting the amount, the backlash amount G ′ can be set appropriately.

The electronic component mounting apparatus described in the above embodiment operates as follows. The board carry-in conveyor 5 receives the printed board sent from the previous process and transfers it onto the guide of the Y table 32 of the XY table 3. The printed board on the guide is positioned and fixed to the Y table 32. The printed circuit board fixed to the Y table 32 is moved in the XY direction in combination with the movement of the X table 31. The drive motors in the X and Y directions are NC of the electronic component mounting apparatus.
The XY table 3 is connected to a control device and its rotational drive is controlled. Thus, the XY table 3 positions the mounting work position M of the mounting head 2 at a position where a predetermined electronic component on the printed circuit board surface is to be mounted. The carry-out conveyor 6 receives the printed circuit board from the guide of the Y table 32 and sends it to the subsequent process.

A plurality of mounting heads 2 are arranged at equal intervals on the periphery of the index table 1 and are mounted at equal intervals. Each of the mounting heads 2 rotates as the index table 1 rotates.
It is circulated again on the component supply unit 7 from the component supply unit 7 for picking up a predetermined electronic component, through the mounting work position M on the XY table 3. Index table 1
Is rotated by a servo motor 129 which is connected to an NC controller of the electronic component mounting device and whose rotational drive is controlled. That is, the rotation of the servo motor 129 depends on the gear 135.
Is transmitted to the outer teeth 108 of the gear 107 through the gear, the gear 107 is fixed to the index table 1, and is integrally formed with the shaft 10.
The NC controller that rotates around 1 stores a mounting program, and when the mounting program controls the rotation drive of the index table 1 and the predetermined mounting head 2 stops on a predetermined supply device, The suction nozzle 21 is moved up and down to pick up a predetermined electronic component to suck and hold the predetermined electronic component. The mounting head 2 that suction-holds the predetermined electronic component reaches the mounting work position M as the index table 1 rotates. Then, the NC control device has the above-mentioned X-
The driving means (not shown) of the Y table 3 is drive-controlled to position the position where the predetermined electronic component of the printed board is to be mounted on the mounting work position M, and subsequently, the mounting head 2 which sucks and holds the predetermined electronic component. The component suction nozzle 21 is moved up and down to place the electronic component on the printed circuit board surface and release the suction.

FIG. 4 shows the external teeth 10 of the gear 135 and the gear 107.
8 shows an enlarged meshing portion with 8, showing a state where both teeth are in contact with each other toward one side, and shows that backlash occurs in a properly meshed state. In the case of the present embodiment, backlash The amount G is 15 to 20 μm. There is a limit even if the diameter of the gear 107 is set to a large diameter that is close to the diameter of the rotation locus of the mounting head 2 that is attached to the peripheral portion of the index table 1 and that rotates so that the influence of backlash does not increase as much as possible. . Further, the existence of backlash means that there is play in the meshing of both gears, and in the case where the servomotor 129 has a built-in rotation detector for generating a rotation angle signal and is fed back to the NC controller side as in this embodiment. , Gear 135 and external tooth 1
08 meshing is outside the feedback loop,
Although the positioning of the rotation angle of the servo motor 129 can be ensured with high accuracy, the play is interposed in the positioning of the mounting head 2 in the rotation direction. In addition, as a structure for directly detecting the position of the rotation angle of the index table 1, a magnetic scale of a rotation angle detector is attached to the index table 1 and a signal from a sensor is fed back, or a shaft directly connected to the index table 1 is rotated. If a rotation detector is attached to the and the rotation angle signal is fed back, the gear 1
The meshing of 35 with the external teeth 108 is within the feedback loop. The responsiveness of this feedback loop is determined by the loop gain of the NC control device, but the response time of the portion detecting the rotation angle signal in the feedback loop must be sufficiently shorter than the response time determined by the loop gain. If the detection response time is slow, the loop gain must be lowered in order to secure the stability of the feedback loop, and as a result the tact time of the electronic component mounting device cannot be shortened. In addition to the mass of the movable part including the index table 1 and the elastic deformation of the drive system, the main cause is the presence of backlash. Even if the backlash is outside the feedback loop, the effect is inevitable. Further, the index table 1 may continue to move within the range of backlash. If this movement is large, hunting may occur.

FIG. 5 and FIG. 6 show that the rotation control is started from the state in which the servo motor 129 is stopped by the control of the NC controller of the electronic component mounting apparatus, and the rotation speed is increased by a predetermined rise and the rotation speed is increased to a constant speed. It is a graph which shows rotation with time, followed by a predetermined descent progress, decreasing a rotation speed, and finally stopping as time progresses. The graph shows the servo motor 1
The change in the rotation speed of 29 and the change in the distance at which the mounting head 2 approaches the one stop position on the rotation locus and then stops are shown as line graphs. Servo motor 1
The rotation speed of 29 indicates that the reaction is accurate under the control of the NC controller.

The line graph of the moving distance of the mounting head 2 shown in FIG. 5 shows a case where the mounting head 2 is repeatedly returned by about 10 μm and then overrun by about 10 μm even if the servomotor 129 is stopped (case 1 ), Even if the servo motor 129 stops, the mounting head 2 continues to move, overruns once, then returns too much, and overruns again and attenuates (case 2).
A case in which the movement of the mounting head 2 does not follow immediately before 29 decelerates and stops, and continues to move even after the servo motor 129 stops and reaches a predetermined position with a delay and then temporarily returns to settle (case). 3), etc. are confirmed by the result of actual measurement. It can be seen that the position of the mounting head 2 at the time when the mounting work is executed varies with time in each case. If only one of these cases appears, there should be no problem, but we cannot hope for that.

FIG. 6 shows a case where the torque control mechanism is operated. The gear 154 that fits on the output rotary shaft 155 of the servomotor 160 and rotates integrally is an index table 1
It is meshed with the internal teeth 109 of the gear 107 that is fixedly attached to and rotates integrally, and drives the servo motor 160 in the opposite direction to the direction in which the servo motor 129 rotationally drives the gear 107 through the engagement of the external teeth 108. The counter torque is transmitted to the gear 107. The magnitude of the opposing torque is set to such an extent that the rotational drive of the servomotor 129 is not stopped or opposed to cause reverse rotation. Further, the rotational driving of the servo motor 160 is intermittently controlled in accordance with the rotational driving of the servo motor 129 so that the torque is not acted against. The line graph of the rotation speed of the servo motor 129 and the moving distance of the mounting head 2 shown in FIG. 6 includes a line graph for controlling switching between the operation (torque ON) and the non-operation (torque OFF) of the torque opposed to the servo motor 160. , Indicates that the servo motor 160 is operated at the time when the servo motor 129 starts deceleration. In this case, when the servo motor 129 stops, the mounting head 2 reaches a predetermined position and temporarily returns to settle down (case 1). The case where the mounting head 2 does not reach the predetermined position even if the servo motor 129 stops and then returns to the same position shown in the case 1 (case 2) (case 2), etc. is confirmed by the measurement results. . It can be seen that the position of the mounting head 2 at the time of executing the mounting work with time elapses is stabilized at a constant position as compared with the case without the torque control mechanism shown in FIG. Servo motor 129
Is controlled so as to maintain the stop, and the servo motor 160 maintains the opposing torque. The operation of the servo motor 160 is stopped before the servo motor 129 starts the rotational driving again after the time when the mounting work is executed. Eliminate the opposing torque. These operations are controlled by the NC controller of the electronic component mounting device.

[0025]

According to the electronic component mounting apparatus of the present invention, by the operation of the torque control mechanism described above, the mounting head 2 is against the influence of backlash caused by the meshing of the outer teeth 108 of the gear 135 and the gear 107. The accuracy of the stop position of the mounting head 2 is improved by reducing variations in the stop position during intermittent rotation. Servo motor 16 of torque control mechanism
When 0 is rotationally driven and a counter torque is applied, as shown in FIG.
As shown in FIG. 5, a counter torque in the direction of arrow F is transmitted from the gear 154 to the outer teeth 108 of the gear 107 via the inner teeth 109 of the gear 107, while the torque for maintaining the rotation drive or stop of the servo motor 129 is the gear. Arrow D to 135
Acts as directional torque. Therefore, the meshing of the gear 107 that rotates integrally with the index table 1 and the gear 135 that transmits the rotational drive of the servomotor 129 makes contact with a certain tooth surface P and maintains the stopped state. As a result, the backlash is biased to a certain side, and the influence of the backlash is removed to reduce the variation in the stop position during the intermittent rotation of the mounting head 2. The improvement of the stopping accuracy of the mounting head 2 increases the stopping accuracy of the supply device and ensures the picking up of the electronic component from the predetermined supply device of the component supply unit 7 by the mounting head 2. Further, the mounting position accuracy of the electronic component on the printed circuit board at the mounting work position M of the mounting head 2 is improved. Further, even if the backlash is in the feedback loop, it is possible to secure the stability of the feedback loop without lowering the loop gain, and as a result, it is possible to shorten the tact time of the electronic component mounting device. Even if the backlash is outside the feedback loop, there is an effect of ensuring the stability of the same feedback loop.

[0026]

[Brief description of drawings]

FIG. 1 is a plan view showing a meshing configuration of a gear integrated with an index table, a gear of an intermittent rotation drive motor, and a gear of a torque control mechanism.

FIG. 2 is a side sectional view showing an index table, a mounting head, and a rotary drive mechanism for rotating the index table.

FIG. 3 is a cross-sectional view showing a part of a rotary drive mechanism from a side surface.

FIG. 4 is an enlarged view showing a meshing portion between a gear integrated with an index table and a gear of an intermittent rotation drive motor.

FIG. 5 is a graph showing how the intermittent rotation drive motor starts rotating to increase the rotation speed and then decelerates to a stop, and the distance at which the mounting head approaches the stop position. It is a graph shown.

FIG. 6 is the same graph as above, showing the case where the torque control mechanism is operated.

FIG. 7 is a plan view showing an overview of an embodiment of an electronic component mounting apparatus of the present invention.

FIG. 8 is a front view showing an overview of an embodiment of an electronic component mounting apparatus of the present invention.

FIG. 9 shows an outline of an entire mounting apparatus as an example of an electronic component mounting apparatus for carrying out the present invention.

[Explanation of symbols]

1 Index Table 2 Mounting Head 3 XY Table 7 Component Supplying Part 21 Component Adsorbing Nozzle 107 Gear 108 External Teeth 109 Internal Teeth 129 Servo Motor 134 Gear Shaft 135 Gear 160 Servo Motor 154 Gear D Direction of Rotational Driving Torque F Direction in which opposing torque is transmitted G Backlash amount generated by meshing of external teeth 108 and gear 135 G'Backlash amount generated by meshing of internal teeth 109 and gear 154 M Mounting work position P Point of contact with a constant tooth surface X Board loading Unloading direction Y A direction parallel to the substrate transfer surface and perpendicular to the X direction

Claims (5)

[Claims] 1. A plurality of mounting heads each having a component suction nozzle are arranged at a peripheral portion of an index table which is intermittently rotated, and the mounting head is stopped at a position corresponding to the intermittent rotation of the index table. A component supply unit in which a component suction nozzle of the mounting head picks up an electronic component is arranged, and an electronic component picked up by the component suction nozzle is picked up on a printed circuit board surface that is positioned by moving up and down the component suction nozzle of the mounting head. In an electronic component mounting device having a mounting work position for mounting, a driven gear is fixed to the index table by sharing a rotation center, and a driven gear connected to a drive motor is meshed with the driven gear to intermittently rotate the driven gear. Along with the above, a torque control means is provided for transmitting torque to the driven gear that opposes the drive gear. An electronic component mounting apparatus characterized by. 2. The torque control means, wherein the driven gear is meshed with a transmission gear that rotates integrally with the output rotation shaft of the torque control motor, and the torque control motor is driven in the direction opposite to the intermittent rotation drive of the drive motor. The electronic component mounting apparatus according to claim 1, wherein the driven gear is configured to be rotationally driven to transmit a counter torque to the driven gear. 3. The electronic component mounting apparatus according to claim 1, wherein a plurality of said mounting heads are arranged and mounted at a peripheral portion of said index table at equal intervals. 4. The electronic component mounting apparatus according to claim 1, wherein the torque control means controls switching between actuation and non-actuation of a counter torque transmitted to the driven gear in accordance with intermittent rotation drive of the drive motor. . 5. The electronic component mounting apparatus according to claim 1, wherein the torque control means is configured to be able to set a magnitude of a counter torque transmitted to the driven gear.