JPH07266154A - Holding head of parts - Google Patents

Abstract

PURPOSE:To provide a holding head of parts, capable of adjusting their sense and height accurately by holding those of object parts such as electronic parts, in an assembly technical field of an electronic parts mounting device or the like. CONSTITUTION:This holding head is provided with a shaft 23 with a spline part 24 and a thread part 25, a nozzle 21 being connected to this shaft 23 and holding parts, and a first rotator 27 engaging with the spline part 24 so as to make the shaft 23 vertically movable, respectively. In addition it is also provided with a first rotatively driving means adjusting a turning angle of the holding part 21 is rotating the shaft 23 by way of rotating the first rotator 27, a second rotator 35 with a nut part 34 to be screwed in the thread part 25, and a second rotative driving means adjusting height of the holding part 21 in moving the shaft 23 up and down by rotating the second rotator 35 as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component holding head capable of holding various components such as electronic components and precisely adjusting the height and direction of the components.

[0002]

2. Description of the Related Art In the field of assembly technology and the like, a holding head is used to convey a component from one position to another position or to temporarily retain a component conveyed along a conveyance path. As an example of a technique in which such a holding head is used, there is an electronic component mounting apparatus that mounts an electronic component on a printed circuit board or the like.

Next, a conventional holding head used in an electronic component mounting apparatus will be described. FIG. 8 is a sectional view of a holding head included in a conventional electronic component mounting apparatus.
The holding head 1 has a cylindrical case 2 as a main body, and a vertical shaft 3 is housed in the center thereof. A nozzle 5 that holds the electronic component 4 by vacuum suction is connected to the lower end of the shaft 3. A spline portion 6 is formed on the upper portion of the shaft 3, and the spline portion 6 is held by a spline bearing 7 slidably in the vertical direction.

Reference numeral 8 is a first rotating body as a rotor, and a spline bearing 7 is mounted on an inner surface of a cylindrical portion 9 vertically provided at a lower portion thereof. A magnet 10 is mounted on the outer peripheral surface of the first rotating body 8, and a coil 11 facing the magnet 10 is mounted on the upper inner surface of the case 2. The first rotating body 8, the magnet 10, and the coil 11 constitute a hollow motor, and when a current is passed through the coil 11, a magnetic force is generated, and the first rotating body 8 is centered on the axial center line NA of the shaft 3. To θ rotation. Then, the shaft 3 also rotates by θ around the axial center line NA, and the rotation angle (direction) of the electronic component 4 vacuum-sucked by the nozzle 5 is adjusted.

A second rotating body 12 is mounted on the lower portion of the shaft 3. A magnet 13 is attached to the outer peripheral surface of the second rotating body 12. A coil 14 facing the magnet 13 is mounted on the inner peripheral surface of the lower portion of the case 2. Second rotating body 12, magnet 13, coil 1
Reference numeral 4 constitutes a hollow voice coil motor. Therefore, when a current is passed through the coil 14, a magnetic force is generated and the shaft 3 moves up and down. When the shaft 3 moves up and down, the nozzle 5 vacuum suctions and picks up the electronic component 4 provided in the parts feeder, and the vacuum suctioned electronic component 4 is mounted on the printed circuit board.

A bracket 16 is attached to the lower portion of the shaft 3 via a rotary bearing portion 15. The bracket 16 has a hook-shaped cross-section, and a linear scale 17 forming a linear encoder and a sensor 18 for reading the linear scale 17 are provided on the outer surface of the bracket 16. The linear scale 17 and the sensor 18 measure the amount of elevation of the shaft 3. The reading result of the sensor 18 is fed back to a control unit (not shown) to control the amount of electricity supplied to the coil 14.

[0007]

In the structure of the above-mentioned conventional holding head 1, the rotating operation by energizing the coil 11 constituting the hollow motor and the vertical operation by energizing the coil 14 constituting the voice coil motor are separated. And then do
Linear scale 17 and sensor 18 for detecting height
Has to be attached to the shaft 3 via the rotary bearing portion 15. However, with such a configuration, rattling between the shaft 3 and the rotary bearing portion 15 is unavoidable, so the position of the shaft 3 and the position of the linear scale 17 are displaced, and as a result, the reading of the sensor 18 is performed. There is a problem that the height of the nozzle 4 cannot be accurately controlled because the value is wrong and the feedback value from the sensor 18 to the control means is wrong.

Further, when the coil 14 is not energized, there is no support for the shaft 3 and the shaft 3 falls naturally. Therefore, the coil 14 must be energized at all times so that the shaft 3 does not fall naturally. There was a point.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems of the conventional holding head and to provide a holding head for a component which can accurately and accurately control the height of a holding portion such as a nozzle.

[0010]

To this end, the present invention provides a shaft having a spline portion and a screw portion, a holding portion which is connected to the shaft and holds a component, and a shaft which can move up and down. First engaging with the spline portion
Rotating body, a first rotating drive means for rotating the shaft by rotating the first rotating body around the axis of the shaft, and adjusting the rotation angle of the holding portion; and the screw. A second rotating body having a nut portion that is screwed into the shaft portion, and the second rotating body is rotated about the axis of the shaft to move the shaft up and down to increase the height of the holding portion. A component holding head is composed of a second rotary drive means for adjustment, and a control means for controlling the drive of the first rotary drive means and the second rotary drive means.

[0011]

According to the above construction, the rotation angle and height of the holding portion can be adjusted by rotating the first rotating body and the second rotating body. Further, the first detecting means and the second detecting means are installed separately from the shaft, and the rotation amount of the second rotating body is detected, whereby the height of the holding portion can be accurately controlled.
Further, by screwing the nut portion onto the screw portion, it is possible to prevent the shaft from dropping naturally when the power is not supplied.

[0012]

【Example】

(Embodiment 1) Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view of an electronic component mounting apparatus according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a holding head provided in the electronic component mounting apparatus. In FIG. 1, 51 is a table device, and a movable table 52 is mounted on the upper surface thereof. On the movable table 52, a plurality of parts feeders 53 having electronic parts are arranged in parallel. When the motor 54 of the table device 51 is driven, the movable table 52
Moves in the X direction along the guide rail 55 and stops the parts feeder 53 equipped with predetermined electronic parts at the pickup position.

Reference numeral 56 denotes a moving table device, which is constructed by stacking an X table 57 and a Y table 58.
Reference numeral 60 is a drive motor for the X table 57, and 61 is a drive motor for the Y table 58. A substrate holding table 59 is provided with a clamper 62 on the substrate holding table 59, and the printed circuit board 63 is clamped by the clamper 62 and positioned. 14 is a printed circuit board 63
Is an electronic component mounted on. When the X table 57 and the Y table 58 are driven, respectively, the printed circuit board 63 moves to X
Direction, Y direction.

A linear table device 65 has a bracket 66 mounted on the front surface thereof. The holding head 20 of the electronic component 14 is mounted on the bracket 66. The holding head 20 includes a nozzle 21 as a holding unit that holds the electronic component 14 by vacuum suction. When the motor 67 is driven, the holding head 20 mounted on the bracket 66 moves in the Y direction along the guide rail 68.

The holding head 20 moves above the parts feeder 53 stopped at the pickup position, and the nozzle 21 moves up and down there, whereby the parts feeder 5 is moved.
The electronic component 14 provided in No. 3 is vacuum-sucked and picked up. Next, the holding head 20 moves above the printed circuit board 63, and the electronic component 14 that is vacuum-sucked by the nozzle 21 is observed by the camera 69 in the middle of the holding head 20, and the X-ray
Misalignment in the direction, Y direction, and horizontal rotation direction (θ direction) is detected. Based on the detection result, the nozzle 21 is rotated about its axis to correct the positional deviation in the θ direction. The positional deviation in the X direction is corrected by driving the X table 57 to move the printed circuit board 63 in the X direction, and the positional deviation in the Y direction is driven by the Y table 58 to move the printed circuit board 63 in the Y direction. To correct it. Next, the holding head 20 is attached to the printed circuit board 63.
Of the electronic component 14 is mounted on the printed board 63 by moving the nozzle 21 up and down. At this time, the movement table position 56 is driven to adjust the position of the printed board 63 so that the electronic component 14 is mounted at a predetermined coordinate position. The lifting stroke of the vertical movement of the nozzle 21 described above is precisely adjusted by the thickness of the electronic component 14.

As described above, the nozzle 21 provided in the holding head 20 performs vertical movement and rotation operation,
Next, the detailed structure of the holding head 20 provided with the mechanism for the vertical movement and the rotary movement will be described with reference to FIG.

In FIG. 2, reference numeral 22 denotes a cylindrical case which is the main body of the holding head 20, and a shaft 23 is vertically inserted in the center of the case. The nozzle 21 is connected to the lower end of the shaft 23. Although not shown, the shaft 23 is connected to the vacuum device by a tube, and when the vacuum device is driven, the electronic component 14 is vacuum-sucked to the lower end portion of the nozzle 21, and the vacuum suction state is released.

An upper portion of the shaft 23 is a spline portion 24 in which a vertical groove is formed, and a lower portion thereof is a screw portion 25 in which a screw groove is formed. A spline bearing 26 is engaged with the spline portion 24. The spline bearing 26 is mounted on the inner peripheral surface of a first rotating body 27 as a rotor. Reference numeral 28 is a bearing for bearing the first rotating body 27 and the like.

A first magnet 29 is mounted on the outer peripheral surface of the first rotating body 27. Further, the first coil 3 facing the first magnet 29 is provided on the circumferential surface of the case 22.
No. 0 is mounted, and the first rotating body 27, the first magnet 29, and the coil 30 serve as a first rotation driving unit that constitutes a hollow motor. A disc-shaped scale plate 31 is mounted on the outer peripheral surface of the upper portion of the first rotating body 27 coaxially with the first rotating body 27, and the scale plate 31 is optically mounted on the inner peripheral surface of the case 22. A first sensor 32 for detecting the above is provided. The scale plate 31 and the first sensor 32 serve as a first detection unit that detects the rotation angle of the shaft 23.

When a current flows through the first coil 30, the magnetic force causes the first rotating body 27 to make a θ rotation around the axis NA of the shaft 23, and through the spline bearing 26, the first rotating body 27 is rotated. The shaft 23 that engages with the shaft 27 has an axis N
Rotate θ around A. The rotation angle of the shaft 23 is detected by the first sensor 32. Shaft 23
As described above, the position deviation of the electronic component 14 vacuum-sucked by the nozzle 21 in the θ direction (rotation direction) is corrected by rotating the.

A nut portion 34 is screwed onto the screw portion 25. The nut portion 34 is attached to the inner peripheral surface of the second rotating body 35. A second magnet 36 is attached to the outer peripheral surface of the second rotating body 35. Further, a second coil 37 facing the second magnet 36 is mounted on the inner peripheral surface of the case 22. The second rotating body 35, the magnet 36, and the second coil 37 serve as a second rotation driving unit that constitutes a hollow motor. A disc-shaped scale plate 38 is mounted coaxially with the second rotary body 35 on the lower outer peripheral surface of the second rotary body 35, and the scale of the scale plate 38 is detected on the inner peripheral surface of the case 22. The second sensor 39 is mounted. The scale plate 38 and the second sensor 39 are connected to each other by the second rotating body 35.
It is a second detection means for detecting the rotation angle of the.

When a current flows through the second coil 37, the magnetic force causes the second rotating body 35 to rotate. Then, the nut portion 34 also rotates, and the screw portion 25 screwed into the nut portion 34.
The shaft 23 having a vertical axis moves up and down. The spline portion 24 and the spline bearing 26 allow this vertical movement. The second sensor 39 detects the rotation angle of the second rotating body 35, so that the amount of elevation of the shaft 23 is detected. The vertical movement of the shaft 23 in this way causes the vertical movement of the nozzle 21 described above.

FIG. 4 is a block diagram of the control system of the holding head according to the first embodiment of the present invention. In the figure, A is a first rotation driving means including the first rotating body 27, the first magnet 29, and the first coil 30, and B is a second rotating body 35 and a second rotating body.
It is a second rotation driving means composed of the magnet 36 and the second coil 37. 50A is a control means, and is provided with a first drive circuit 42 to which the first sensor 32 is connected and a second drive circuit 43 to which the second sensor 39 is connected. Reference numeral 44 denotes a command unit, which is the first pulse generation circuit 45.
And the second drive circuit 4 via the second pulse generation circuit 46.
2 and the second drive circuit 43. The first drive circuit 42 controls the first rotary drive means A, and the second drive circuit 43 controls the second rotary drive means B.

The command section 44 stores a control program for the apparatus, and stores in advance data such as the target rotation angle θ1 of the nozzle 21 and the target lift amount H1 of the nozzle. The target rotation angle θ1 and the target ascending / descending amount H1 can be input one by one by operating the keyboard (not shown) by the operator.

Now, the holding head 20 of the present invention having the above structure.
In the case of, in order to correct the rotation angle (direction) of the electronic component 14, when a current is passed through the first coil 30 to rotate the shaft 23, the screw portion 25 screwed into the nut portion 34 also rotates, The shaft 23 slightly moves in the vertical direction.
When the vertical movement amount of the nozzle 21 must be controlled with high precision and accuracy, this fine movement in the vertical direction results in a change in the height of the nozzle 21 (height error). Therefore, a control method for eliminating this height error will be described next.

FIG. 3 is an enlarged view of the lower end portion of the shaft of the holding head provided in the electronic component mounting apparatus according to the first embodiment of the present invention. 3 and 4, H1 is the nozzle 2
The target lift amount of 1 (falling distance in this embodiment), θ1 is the target rotation angle. First, in FIG. 4, a rotation angle command of θ1 is output from the command unit 44 to the first pulse generation circuit 45. Then, the first pulse generation circuit 45 outputs a pulse signal P1 corresponding thereto to the first drive circuit 42, and the first drive circuit 42 outputs a predetermined current I1 to the first rotation drive means A.
Flow through the first coil 30 provided in the. Then, the shaft 23 rotates due to the magnetic force generated in the first coil 30. The rotation angle of the shaft 23 is detected by the first sensor 32, and its feedback signal F1 is fed back to the first drive circuit 42.

Next, a method for lowering the shaft 23 by the target lift amount H1 will be described. In FIG. 3, when the shaft 23 rotates according to the command of the target rotation angle θ1, the screw portion 25 of the shaft 23 is screwed into the nut portion 34, so the shaft 23 is slightly lowered. ΔH is a minute height change (height error) associated with this rotation.

Therefore, when lowering the target lift amount H1, the second rotation driving means B is provided with the second rotation driving means B so as to correct this change amount ΔH and to lower by H2 = H1−ΔH.
An electric current is passed through the coil 37. The rotation angle θ2 of the shaft 23 for lowering by H2 is (Equation 1).

[0029]

[Equation 1]

In (Equation 1), the shaft 23 of L is 3
It is the amount of lowering of the shaft 23 when rotated by 60 °. Therefore, in FIG. 4, the command unit 44 outputs a rotation angle command of θ2 to the second pulse generation circuit 46, and in response thereto, the second pulse generation circuit 46 outputs the pulse signal P2, The current I2 flows from the drive circuit 43 of FIG. 2 to the second coil 37, the shaft 23 rotates by θ2, and H2 descends. The rotation angle of the shaft 23 accompanying this lowering is the second
Of the feedback signal F2 detected by the sensor 39 of
Is fed back to the second drive circuit 43. As described above, in this holding head 20, in order to descend the shaft 23 with high accuracy, a minute amount that accompanies the rotation of the shaft 23 by the target rotation angle θ1 by causing the current I1 to flow through the first coil 30. It is necessary to correct the descending amount of the shaft 23 by adding the change amount ΔH of the height as a correction value.

(Second Embodiment) Next, another control method will be described. FIG. 5 is a block diagram of a control system of the holding head according to the second embodiment of the present invention. The control means 50B of this second embodiment
4 is that the pulse signal P1 output from the first pulse generation circuit 45 is input to the second drive circuit 43 as well as the first drive circuit 42, and thus the control of the first embodiment shown in FIG. It differs from the means 50A. Therefore, when the rotation angle command of θ1 is issued from the command unit 44 to the first pulse generation circuit 45, the first pulse generation circuit 45 outputs the corresponding pulse signal P1 to the first drive circuit 42 and the second drive circuit. Circuit 4
Output to 3. Then, the first drive circuit 42 causes a predetermined current I1 to flow through the coil 30 to rotate the shaft 23 by θ1.

On the other hand, the command section 44 outputs a command of the rotation angle θ2 for lowering H1 to the second pulse generating circuit 46, and the second pulse generating circuit 46 outputs the corresponding pulse signal P2 to the second pulse generating circuit 46. Output to the drive circuit 43. Here, as described above, the first pulse generation circuit 45 also outputs the pulse signal P1 to the second drive circuit 43. This pulse signal P1 causes the current I1 to flow through the first coil 30 as described above.
Is input to the second drive circuit 43 as a correction value of the pulse signal P2 for predicting the change amount ΔH of the height of the shaft 23 due to the flow of the pulse signal P2. A current I2 ′ based on the result of correction of the pulse signal P1 to the second coil 37, the shaft 23 is rotated by the magnetic force, and H2 = H1−ΔH
Just lower.

(Third Embodiment) FIG. 6 is a block diagram of a control system of a holding head according to a third embodiment of the present invention. The control means 50C of the third embodiment is different from the control means 50A of the first embodiment in that the feedback signal F1 of the first sensor 32 is also fed back to the second drive circuit 43. In the second embodiment, the pulse signal P2 output from the first pulse generation circuit 45 is added to the second drive circuit 43 as a correction value, but in the third embodiment, the feedback signal F1 and the feedback signal F1 are added. F2 is added as a correction value of the pulse signal P2, and a current I2 ′ based on the corrected result is passed through the second coil 37, so that the shaft 23 is lowered by H2 = H1−ΔH. That is, in the third embodiment, the first sensor 32 detects that the shaft 23 actually descends by ΔH according to the rotation angle command of θ1, and controls the descending amount of the shaft 23.

As described above, various methods of controlling the holding head 20 can be considered. In the third embodiment, the shaft 23
Although the description has been made by taking as an example the case where the shaft 23 is lowered, the control in the case where the current in the opposite direction is passed through the coil to raise the shaft 23 is performed in exactly the same manner.

(Fourth Embodiment) FIG. 7 is a sectional view of a holding head provided in an electronic component mounting apparatus according to a fourth embodiment of the present invention. The holding head 70 of the first embodiment shown in FIG. 2 includes a first rotating body 27, a first magnet 29, and a first coil 30.
In contrast to the hollow motor, the holding head 70 of the fourth embodiment is different in that it constitutes an ultrasonic motor described below. That is, the first rotating body 2
A slide ring 71 is attached to the outer peripheral surface of 7,
The lower end of the spring 72 mounted on the first rotating body 27 is grounded on the upper surface thereof. An elastic body 74 is mounted on the support portion 73 attached to the inner peripheral surface of the case 22. A piezoelectric body 75 is mounted on the lower surface of the elastic body 74, and the upper surface of the elastic body 74 contacts the lower surface of the slide ring 71. Slide ring 71 is spring 7
It is urged to the elastic body 74 by 2.

Therefore, when the piezoelectric body 75 is supplied with electric power and vibrated, the elastic body 74 also vibrates, and this vibration is transmitted to the slide ring 71, and the first rotating body 27 rotates. The drive means of the holding head 70 can be the drive means shown in FIGS. 4, 5 and 6, and the piezoelectric body 75 is driven by the first drive circuit 42 and the shaft 23 rotates. The control method of the holding head 70 is the same as that of the holding head 20 shown in FIG. 2, and the description thereof will be omitted.

Although the fourth embodiment has been described by taking the holding head of the electronic component mounting apparatus as an example, the holding head of the present invention can be applied as a holding head in other technical fields. Further, in the above-described embodiment, the nozzle 21 that holds the electronic component by vacuum suction is described as an example of the holding unit, but the holding unit may be another mechanism such as a unit that chucks and holds the target component. It is a thing.

[0038]

As described above, the present invention relates to a shaft having a spline portion and a screw portion, a holding portion connected to the shaft for holding a component, and a spline portion for allowing the shaft to move up and down. A first rotating body to be fitted, a first rotating drive means for rotating the shaft by rotating the first rotating body around an axis of the shaft, and adjusting a rotation angle of the holding portion; and a screw portion. A second rotating body having a nut portion that is screwed into the second rotating body; and a second rotating body that rotates the second rotating body around the axis of the shaft to vertically move the shaft to adjust the height of the holding portion. Since the component holding head is composed of the rotation driving means and the control means for controlling the driving of the first rotation driving means and the second rotation driving means, the rotation angle (direction) of the component can be made with a simple configuration. Adjustment and height adjustment with high accuracy It can be done, also possible to prevent the free fall of the shaft.

Further, the control means drives the first rotation driving means to adjust the rotation angle of the holding portion, and the change in the height of the holding portion, which accompanies the adjustment, is taken into consideration in advance, and the second rotation driving is performed. By controlling the means to control the height of the holding portion to reach the target height, it is possible to perform height adjustment with higher accuracy.

Further, it is provided with a first detecting means for detecting the rotation angle of the first rotating body and a second detecting means for detecting the rotating angle of the second rotating body, and the control means includes the first detecting means and the first detecting means. By controlling the second rotation drive means while detecting the output signal of the second detection means, it is possible to perform height adjustment with higher accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view of an electronic component mounting apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a holding head provided in the electronic component mounting apparatus according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a lower end portion of a shaft of a holding head included in the electronic component mounting apparatus according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a control system of a holding head according to the first embodiment of the present invention.

FIG. 5 is a block diagram of a control system of a holding head according to a second embodiment of the present invention.

FIG. 6 is a block diagram of a control system of a holding head according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a holding head provided in an electronic component mounting apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view of a holding head provided in a conventional electronic component mounting apparatus.

[Explanation of symbols]

 20, 70 Holding head 21 Nozzle (holding part) 23 Shaft 24 Spline part 25 Screw part 27 First rotating body 29 First magnet 30 First coil 31 Scale plate (first detecting means) 32 Sensor (first) 34 nut portion 35 second rotating body 36 second magnet 37 second coil 38 scale plate (second detecting means) 39 sensor (second detecting means) 71 slide ring 72 spring 75 piezoelectric body 50A, 50B, 50C Control means A First rotation drive means B Second rotation drive means

Claims (3)

[Claims] 1. A shaft having a spline portion and a screw portion, a holding portion connected to the shaft for holding a component, and a first rotation for engaging the spline portion so that the shaft can move up and down. A body, a first rotation driving means for rotating the shaft by rotating the first rotating body around the axis of the shaft, and adjusting the rotation angle of the holding portion; A second rotating body having a nut portion to be screwed, and rotating the second rotating body around the axis of the shaft to move the shaft up and down to adjust the height of the holding portion. A holding head for a component, comprising: a second rotation driving means; and a control means for controlling driving of the first rotation driving means and the second rotation driving means. 2. The control means preliminarily allows for a change in the height of the holding portion that accompanies the drive of the first rotation driving means to adjust the rotation angle of the holding portion, 2. The component holding head according to claim 1, wherein the second rotation drive means is controlled to control the height of the holding portion to a target height. 3. A first detecting means for detecting a rotation angle of the first rotating body, and a second detecting means for detecting a rotating angle of the second rotating body, wherein the control means comprises: 2. The component holding head according to claim 1, wherein the second rotation drive means is controlled while detecting the output signals of the first detection means and the second detection means.