JP2000252693A - Mounting head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mounting head capable of accurately controlling a rotation or lifting operation of a suction nozzle, without causing deformations in a shaft. SOLUTION: A head unit comprises a lifting mechanism disposed at the lower side of a shift and a rotation mechanism disposed at the upper side of the shaft. The shaft provided with a suction nozzle at the front end and having an air supply and exclusion path inside is lifted up and down and rotated on the head unit. This mounting head carries parts sucked by the suction nozzle to a mounting position. In this case, this mounting head comprises a lower shaft 35 retained at a lifting mechanism side, an upper shaft 37 retained at a rotation mechanism side, a flexible joint 36 in which the end part at the connection side of the one shaft 35 is freely engaged with the end part at a connection side of the other shaft 37, and in a state in which paths inside both the shafts are interlocked with each other, the upper shaft 35 is connected to the lower shaft 37, and an elastic sealing material 50 for sealing a clearance between freely engaged shafts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting head in a component mounting system, and more particularly, a shaft having an air supply / discharge passage is moved up and down or rotated on a head unit, and a component is picked up by a suction nozzle provided at a tip of the head unit. The present invention relates to a mounting head that sucks and conveys to a predetermined mounting position.

[0002]

2. Description of the Related Art Conventionally, in a mounting system for mounting an electronic component on a board, a head unit is reciprocated between a component supply unit and a printed board positioned at a predetermined work position, for example. This head unit is provided with an R-axis servomotor and a Z-axis servomotor,
A hollow shaft provided with an air supply / discharge passage can be rotated around a vertical axis or can be moved up and down. A suction nozzle for suctioning electronic components is attached to the tip of the hollow shaft.

As described above, in the configuration in which the air supply / discharge passage is provided in the rotating or ascending / descending shaft and the inside of the hollow shaft is decompressed and the electronic components are sucked by the suction nozzle, a suction hose or the like is externally connected to the suction nozzle. There is no need to connect, and the air supply / discharge system can be configured simply.

[0004] A part of the hollow shaft is integrally provided with a spline portion which can slide vertically in an outer cylinder to which the pulley is fixed, so that the rotational force of the R-axis servomotor is applied to the pulley and the outer cylinder. Can be communicated via When the suction nozzle is moved up and down by driving the Z-axis servomotor, the spline is configured to slide up and down.

[0005]

However, in the above-described conventional mounting head, the rotation center axis of the bearing portion of the spline portion and the rotation center axis of the other hollow shaft bearing portion are caused by an error in assembling the head unit. Are not always aligned on the same axis, and when eccentricity or declination occurs, an excessive force acts between them, causing deformation of the hollow shaft or impairing the smoothness of operation.

Therefore, in such a state, there is a problem that high reliability cannot be obtained even if control is performed based on the output of the encoder for detecting the rotation speed of the R-axis servomotor.

The present invention has been made in order to solve such a problem, and it is possible to raise or lower or rotate the suction nozzle without causing deformation such as twisting in the hollow shaft to which the suction nozzle is attached. Accordingly, the present invention provides a mounting head capable of improving the reliability of mounting control.

[0008]

According to the present invention, a shaft provided with a suction nozzle at the tip and having an air supply / discharge passage therein is provided with an elevating mechanism disposed at a lower portion of the shaft and an upper portion of the shaft. In a mounting head that moves up and down or rotates on a head unit equipped with a rotating mechanism and conveys a component sucked by a suction nozzle to a mounting position, a lower shaft held by a lifting mechanism side and an upper shaft held by a rotating mechanism side A shaft and a universal joint that connects the upper shaft and the lower shaft in a state where the connection side end of one shaft is loosely fitted to the connection side end of the other shaft and the passages inside both shafts communicate with each other are loosely fitted. And a resilient sealing material for sealing a gap between the shafts.

According to this structure, the shaft is divided into a lower shaft held on the lifting mechanism side and an upper shaft held on the rotating mechanism side and connected by a universal joint, so that both shafts are aligned on the same axis. At least, the suction nozzle can be rotated or moved up and down without deformation such as twisting.

In the present invention, the specific configuration of the loosely fitting portion of the shaft is as follows. The outer diameter of the loosely fitting portion of the shaft on the connecting side is larger than the outer diameter of the loosely fitting portion of the shaft. It is preferable to form an enlarged diameter passage having a diameter, and to attach an elastic sealing material to the enlarged diameter passage.

According to this configuration, the shaft on the loose fit side is connected to the shaft on the loose fit side in a state of floating in the enlarged diameter passage, so that the eccentricity or eccentricity generated in the shaft when rotating or ascending or descending is absorbed. can do.

Further, in the present invention, it is preferable that the seal member is constituted by an O-ring which comes into annular contact with the peripheral surface of the shaft connection side end on the loosely fitting side.

With this configuration, the rounded portion of the O-ring is brought into contact with the peripheral surface of the connecting end of the shaft, so that the gap between the floating shafts can be sealed with an appropriate surface pressure to maintain airtightness.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on one embodiment shown in the drawings.

FIG. 1 is a plan view schematically showing an entire surface mounting machine (hereinafter, simply referred to as a mounting machine) to which the present invention is applied.

In FIG. 1, a conveyor 2 for transporting a substrate is arranged on a base 1, and a printed circuit board 3 (indicated by a two-dot chain line) is transported on the conveyor 2 so as to stop at a predetermined mounting position. It has become.

At the side of the conveyor 2, a component supply unit 4
Is arranged. The component supply unit 4 includes a plurality of rows of tape feeders 4a. Each of the tape feeders 4a stores small chip components such as ICs, transistors, and capacitors at predetermined intervals, and derives a tape from the reel. The feeding of the tape is controlled by a ratchet type feeding mechanism, and the tape is intermittently fed as components are pipped up by a head unit 5 described later.

Above the base 1, a head unit 5 for mounting components is provided. The head unit 5 is mounted in the X-axis direction (the direction in which the conveyor 2 is disposed) and the Y-axis direction (in the plane, the X-axis direction). (In the direction perpendicular to).

More specifically, a pair of rails 6 extending in the Y-axis direction extend on the base 1, and a head unit support member 7 is installed on the rails 6. The head unit support member 7 is screwed with a ball screw shaft 9 via a nut portion 8, and the ball screw shaft 9 is connected to a rotation shaft of a Y-axis servomotor 10. The head unit support member 7 has a guide member 11 extending in the X-axis direction,
The head unit 5 is movable along the guide member 11. Then, by driving the X-axis motor 12, the head unit 5 is moved through the ball screw shaft (not shown).
It is designed to move in the axial direction.

FIG. 2 is a side view showing the structure of the head unit 5, and a part thereof is shown in cross section. FIG. 3 is FIG.
It is a front view of one of the heads 20 is moved to the lowermost end,
This shows a state in which the other head 20 is moving to the uppermost end.

In both figures, a head 20 for picking up components is mounted on the head unit 5, and in this embodiment, two heads are arranged side by side in the X-axis direction. Further, the head unit 5 is provided with a lifting drive mechanism for raising and lowering the head 20.

This lifting drive mechanism raises and lowers each head 20 individually. Specifically, a frame 21 holding the head 20 is attached to the head unit 5 so as to be able to move up and down along a guide portion 24 fixed to the head unit 5, and the frame 21 has a nut portion 22. , The nut portion 22 of which is a ball screw shaft 23
Is screwed into.

The ball screw shaft 23 is connected to a rotating shaft 26a of a Z-axis servo motor 26 via a flexible joint 25 for absorbing misalignment, and rotates the Z-axis servo motor 26 forward or backward. Then, the ball screw shaft 23 rotates, and the nut portion 22 screwed with the ball screw shaft 23 moves up and down along the guide portion 24, and as a result, the head 20 moves up and down.

The head unit 5 includes each head 2.
A rotation drive mechanism for rotating 0 around a vertical axis is mounted. The rotation drive mechanism includes an R-axis servo motor 30 provided for each head 20, and the rotational force of the R-axis servo motor 30 is transmitted to a pulley 32 via a transmission belt 31.
And each head 20 can be rotated independently.

More specifically, the pulley 32 includes an outer cylindrical shaft 3.
3 is integrated coaxially and integrated with the pulley 32 by tightening a bolt 33a. This outer cylinder shaft 33
Is rotatably held by the upper bearing portion 34. A hollow spline shaft (upper shaft held on the rotation mechanism side) 35 is coaxially inserted into the outer cylinder shaft 33, and the spline shaft 35 rotates in conjunction with the rotation of the outer cylinder shaft 33, In addition, the inside of the outer cylinder shaft 33 can slide in the Z-axis direction.

A seal 35b such as an O-ring is attached to the upper end of the spline shaft 35 to seal the sliding surface of the outer cylinder shaft 33.

The lower end of the spline shaft 35 is connected to a driven shaft (lower shaft held by the lifting mechanism) 37 via a flexible joint (universal joint) 36, and the driven shaft 37 is disposed in a housing 38. It is rotatably held by a pair of bearings 39 and moves up and down integrally with the housing 38. A nozzle holding shaft 40 is fitted inside the driven shaft 37, and the nozzle holding shaft 4
The suction nozzle 41 is detachably attached to the lower end of the “0”.

The air passage a1 formed in the spline shaft 35 and the air passage a2 formed in the driven shaft 37 communicate vertically, and the air passage a1
Is a pressure reducing device and a pressurizing device (not shown) via a switching valve
Is connected to

At the time of component suction, the switching valve is switched to the pressure reducing device side to reduce the pressure in the air passage a2 and the air passage a1, and the component is sucked by the negative pressure. When the component is mounted, the switching valve is switched to the pressure device side. The pressure is released and a small amount of air is blown out to release the parts. In addition, 4
Reference numeral 2 denotes an encoder for detecting a rotation amount of the spline shaft 35 rotated by the R-axis servomotor 30.

FIG. 4 is an enlarged view showing a connection structure between the spline shaft 35 and the driven shaft 37. As shown in the figure, in the connection structure, the connection side end 35a of the spline shaft 35 as one shaft is fixed to one hub 36a of the flexible joint 36, and the other hub 36b is connected to the other hub 36b. The connection side end 37a of the driven shaft 37 is fixed.

The flexible joint 36 is configured so that the shafts 35 and 37 are parallel to each other in the axial direction (eccentricity).
And each shaft 35, 3
7 is capable of absorbing an angle shift (declination) caused by crossing at an angle.

At the connection side end of the driven shaft 37,
At the upper end of the air passage a2, an enlarged diameter passage a3 having a diameter larger than the diameter of the air passage a2 is formed. The diameter of the air passage a2 is slightly larger than the outer diameter of the spline shaft 35.
The diameter of the spline shaft 35 is
The diameter is expanded in the shape of a cylindrical hole so as to absorb the state of declination with respect to. Therefore, the connection-side end 35a of the spline shaft 35 is disposed in a floating state in the air passage a2 of the driven shaft 37.

An annular groove 37b is formed at the bottom of the enlarged diameter passage a3.
Are formed, and an O-ring 50 as an elastic sealing material is mounted in the annular groove 37b. This O-ring 5
Reference numeral 0 denotes a spline shaft 35 made of synthetic rubber, thermoplastic elastomer, or the like, which comes into contact with the peripheral surface of the connection side end 35a of the spline shaft 35 and floats due to its elasticity.
Holding.

The O-ring 50 is used for sealing by making the rounded portion of rubber come into contact with the O-ring 50. Since an appropriate surface pressure can be obtained and the O-ring 50 can be uniformly deformed, it is suitable as a seal for maintaining airtightness. is there. However, if it can be sealed while absorbing the declination and eccentricity,
Not limited to the above-mentioned O-ring, any elastic sealing material can be used.

Although the enlarged diameter passage in the present invention is provided on the driven shaft 37 side in the above embodiment, it may be provided on the spline shaft 35 side to absorb the eccentricity and eccentricity of the driven shaft 37. .

[0036]

As is apparent from the above description,
According to the present invention, the shaft held by the elevating mechanism and the shaft held by the rotating mechanism are connected via a universal joint in a state where the shaft is loosely fitted, and the shaft is sealed with an elastic sealing material. Without deforming the shaft, and absorbing the declination or eccentricity that occurs on the shaft when rotating or lifting,
It has the advantage that the suction nozzle can be rotated or raised and lowered accurately. In addition, the gap between the floating shafts can be sealed with an appropriate surface pressure to maintain airtightness.

[Brief description of the drawings]

FIG. 1 is a plan view of a mounting machine to which a mounting head of the present invention is applied.

FIG. 2 is a side view showing a configuration of a mounting head according to the present invention, with a partial cutout.

FIG. 3 is a front view of FIG. 2;

FIG. 4 is an enlarged sectional view of a shaft connecting portion shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Conveyor 3 Printed circuit board 4 Component supply part 5 Head unit 7 Head unit support member 10 Y-axis servomotor 12 X-axis servomotor 20 Head 30 R-axis servomotor 35 Spline shaft (upper shaft) 36 Flexible joint 37 Follower shaft (Lower shaft) 41 Suction nozzle 50 O-ring (elastic sealing material) a3 Large diameter passage

Claims (3)

[Claims] A shaft having a suction nozzle at its tip and having an air supply / discharge passage therein is mounted on a head unit provided with a lifting mechanism arranged at a lower part of the shaft and a rotating mechanism arranged at an upper part of the shaft. In a mounting head for moving the component sucked by the suction nozzle to a mounting position, a lower shaft held on the lifting mechanism side, an upper shaft held on the rotating mechanism side, A universal joint for connecting the upper shaft and the lower shaft in a state where the connection side end of the shaft is loosely fitted to the connection side end of the other shaft and the passages inside the two shafts communicate with each other; And a resilient sealing material for sealing a gap between the mounting head and the mounting head. 2. A diameter-enlarging passage having a diameter larger than the outer diameter of the shaft connecting side end on the loosely fitting side is formed at the connection side end of the shaft on the loosely fitting side. 2. The mounting head according to claim 1, wherein said elastic sealing material is mounted in a passage. 3. The mounting head according to claim 2, wherein the sealing material comprises an O-ring that comes into annular contact with a peripheral surface of the shaft connection side end on the loosely fitting side.