JP2001347427A - Pick and place unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PPU carriable at a high speed and having high positioning accuracy. SOLUTION: An X axis slide member 3 is installed on a baseplate 2, a Z axis slide member 4 is installed in the X axis slide member 3, and can be reciprocated in the X axis direction and the Z axis direction by a feed wheel 11 for reciprocatively rotating these members, a circumferential part 12 is arranged in the feed wheel 11, two positioning wheels arranged on the baseplate are simultaneously contacted with the circumferential part of the feed wheel 11 in the initial state and the final stage of reciprocative rotation, and the X axis slide member 3 is locked in the X axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus used in an automatic assembling machine to supply parts from a feeder to an assembling jig.

[0002]

2. Description of the Related Art An apparatus for picking up (picking) parts from a feeder, transporting the parts, and supplying (place) the parts to an assembling jig, a so-called pick-and-place apparatus (hereinafter, PPU).
Is widely used in electronic equipment assembling apparatuses and the like. The PPU is a hydraulic / pneumatic type, a motor type,
There are a solenoid type and a cam type, and there is a gate motion and a swing motion depending on the mode of parts transport. In any case, high-speed operation, high repeatability, and durability are required to improve the efficiency of the assembling apparatus. Of these, the cam type achieves gate motion and swing motion only with a purely mechanical combination,
Even if the control lacks flexibility and versatility, it is superior to other modes in the above-described high-speed operation, high repeatability, and durability.

On the other hand, electronic components and the like have become finer, and the speed of the assembling apparatus has been increased, so that there is a demand for faster and more accurate component supply performed by the PPU. However, the disadvantage of the cam type is that even if there is a slight gap between the cam and the cam follower, the lever transmits and enlarges the displacement caused by the cam.
This gap is also enlarged, which adversely affects the positioning accuracy. For example, in a PPU shown in FIG. 6A, a cam groove (2) provided in a fixed plate (1) is provided.
Is used to guide the drive lever (3) to perform the gate motion. However, if there is no lock mechanism in the X-axis direction, the accuracy of the pick position and the place position is deteriorated.

In order to improve this situation, a spring (5) is attached between the X-axis slide member (4) and the drive lever (3), and the moving side is pushed to the fixed side at the end of the movement. As shown in FIG. 6B, magnets 6 are attached to the moving side and the fixed side, and are repelled at the end of the movement in the X-axis direction. However, since these methods are not forcible locking means, vibration due to repulsion may cause unstable positioning accuracy.In the case of springs, the life is short due to metal fatigue due to repeated wear and impact. There is a risk of becoming.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a PPU having high positioning accuracy and high positioning accuracy.

[0006]

The PPU includes a base plate, an X-axis slide member and a Z-axis slide member, and has a mechanism for driving and positioning.
Note that the X axis, Z axis and Y axis constitute orthogonal coordinates. An X-axis slide member is provided on the base plate so as to be movable along the set X-axis. The X-axis slide member often has a flat plate shape, but may have a block shape. Then, the Z-axis is set on the X-axis slide member, a long hole is provided along this axis, and the Z-axis slide member is provided so as to be movable along the long hole. The Z-axis slide member often uses a so-called LM guide rail in the form of a slide bar. The Z-axis slide member is disposed on the front side of the X-axis slide member. The mechanism for driving and positioning has a feed wheel, four positioning followers and a drive follower. The follower is actually a roller structure.

The feed wheel is a disk-shaped cam, which sets the origin in the Z-axis direction from the center of the disk and reciprocates in a range of a set angle exceeding 90 ° to both sides from the origin. Actually, it is about 125 ° on one side. As a driving source, a stepping motor, a pneumatic rotary actuator, a servomotor, or the like can be used. The cam has a symmetrical shape around the protrusion as a whole, having a protrusion and a circumference, and a smooth relief curve connecting the circumference and the protrusion. Feed wheel is base plate and X
It is arranged between a shaft slide member and is pivotally supported on a base plate by a rotation axis in the Y-axis direction. The four positioning followers are arranged at equal intervals two by two on the back side of the X-axis slide member on the upper side with the above-described elongated hole provided in the Z-axis direction. These rollers are arranged so that two rollers are simultaneously in contact with the cam surface of the feed wheel at the end of the forward rotation and the end of the return rotation of the reciprocating feed wheel. When the two cam followers provided on the X-axis slide member simultaneously contact the feed wheel, the position of the X-axis slide member in the X-axis direction is locked. A drive follower is arranged at the tip of the projecting portion of the feed wheel. The drive follower is engaged with the elongated hole of the X-axis slide member and is engaged with the joint block at the upper end of the Z-axis slide member. The drive follower can be slightly moved in the X-axis direction with respect to the joint block. This is for absorbing the displacement in the X-axis direction when the feed wheel moves more than 90 ° to both sides in the engagement between the drive follower and the joint block.

[0008] The rotation of the feed wheel moves the X-axis slide member and the Z-axis slide member, and the tip of the Z-axis slide member (usually a head for chuck mounting is mounted on this portion) starts an arc motion and an arc motion. Up and down movement is performed before (initial) and after the end of the circular movement (end). At the beginning and the end, two positioning followers simultaneously contact the circumferential portion of the feed wheel to prevent the X-axis slide member from floating in the X-axis direction.
By rotating by 5 °, the head moves up and down. With this structure, the position in the X direction is fixed during the pick operation for picking up the parts and the place operation for releasing the parts, and it is possible to supply the parts with high accuracy. or,
Since the positioning in the X direction is performed by the two positioning followers in contact with the circumferential portion of the feed wheel, the structure is simple and high-speed operation can be performed. Moreover, it has high repetition accuracy, uses no magnets or springs, is structurally strong, and is durable.

[0009]

FIG. 1 shows a PPU 1 according to the present invention.
The structure includes a base plate 2, an X-axis slide member 3, and a Z-axis slide member 4, and further includes a mechanism 5 for driving and positioning. In this embodiment, the X axis is the front-back direction, the Z axis is the up-down direction, and the Y axis is the left-right direction.

The base plate 2 is made of a flat and strong steel plate, and the rail 7 of the X-axis LM guide 6 is fixed along the X-axis set on the lower side of the front side, and the block 8 can run on the rail 7. It is attached. A stepping motor 9 is mounted on the back side, and its output shaft 10 passes through the base plate 2 in the Y-axis direction, that is, on the front side. A feed wheel 11 is fixed to the output shaft 10.
The feed wheel 11 is a kind of plate cam, and has a circumferential portion 12.
And a smooth relief curve portion 14 connecting the circumferential portion 12 and the protruding portion 13 (FIG. 5). A drive follower 15 is attached to the front side of the protruding portion 13 at the front end. The drive follower 15 is a roller. The range of the circumferential portion 12 and the relief curve portion 14 will be described later.

The X-axis slide member 3 is a T-shaped steel plate in which a vertical portion 16 and a horizontal portion 17 are integrally formed. The vertical portion 16 has an elongated hole 18 formed along the set Z-axis. Also, the Z-axis LM guide 19 (FIG. 2)
Block 20 (FIG. 1) is fixed. A rail 21 is inserted into the block 20 and can be moved up and down along the elongated hole 18. At the lower end of the rail 21, a head (not shown) for mounting a pick and place chuck is attached, and at the upper end, a joint block 22 (FIG. 2) is attached. The joint block 22 receives the drive follower 15 of the feed wheel 11 to be in an engaged state, and has both sides opened in the X-axis direction. The drive follower 15 of the feed wheel 11 is engaged with the elongated hole 18 and the joint block 22 on the surface side thereof.

Four positioning followers 23 (a to d) are attached to the back surface of the horizontal portion 17 of the X-axis slide member 3. Each of the rollers is a roller, and two rollers are arranged at the same interval, and four rollers are arranged symmetrically with respect to the central slot 18. The relationship between the arrangement of the positioning followers 23 (a to d) and the form of the feed wheel 11 will be described together with the movement of the X-axis slide member 3 caused by the rotation of the feed wheel. As shown in FIGS. 4A to 4E, when the feed wheel 11 rotates, the X-axis slide member 3 moves back and forth on the base plate 2 by the X-axis LM guide 6. The origin position of the feed wheel 11 is in the state (a) in which the protruding portion 13 stands upright and the drive follower 15 is on the Z axis, and the feed wheel 11 rotates 125 ° forward and backward from this state. That is, the origin position (a)
90 ° (b) backward and 35 ° further (c)
Then, follow the same route and return to the origin (a), then rotate forward 90 degrees (d), and further rotate 35 degrees (e),
Then, the same path is followed to return to the origin position, and one cycle is completed.

In this cycle, the X-axis slide member 3 moves backward together with the Z-axis slide member 4 from (B) to (B), and from (B) to (C) and from (C) to (B). , Only the Z-axis slide member 4 moves up and down. At this time, the drive follower 15 moves the feed wheel 11 over 90 ° to 35 °.
A small forward displacement in the X-axis direction due to the rotation is absorbed by the drive follower moving forward in the joint block 22.

The positioning follower 23c,
23d, the feed wheel 11 is from (b) to (c), from (c)
When it is located at the position (b), that is, at a position beyond the position rotated by 90 ° from the origin, the feed wheel 11 is disposed at a position in contact with the circumferential portion 12 at the same time. Positioning follower 2
Since the 3c and 23d come into contact with the circumferential portion 12 of the feed wheel 11 at the same time, the X-axis slide member 3 cannot be moved in either of the X-axis directions and is locked at that position. This locked state is maintained as long as the positioning followers 23c and 23d are in contact with the circumferential portion 12 even when the feed roller 11 rotates. For this reason, the feed wheel 11
Even if it rotates beyond 0 °, the position of the rail 21 in the X-axis direction on the Z-axis LM guide 19 does not change, and moves linearly up and down at that position. In this situation, the feed wheel 11 rotates forward, (a) to (d), (d) to (e), and (e) to (d).
The same is true when shifting to the position. However, at this time, the positioning followers 23a, 23b
Touches. Feed wheel 11, positioning follower 23
(A to d) and the drive follower 15 constitute a mechanism for driving and positioning.

That is, the circumferential portion 12 has at least
In FIG. 4, while the feed wheel 11 rotates between (b) and (c) or between (d) and (e), the two positioning followers 23 are in contact with each other. In order to eliminate the load caused by the contact of the followers 23 (a to d), a straight line or a curve located inside the circle constituting the circumferential portion 12 is used. However, the line connecting the protruding portion 13 and the circumferential portion 12 is a smooth curve, and particularly, the connecting portion that changes to the circumferential portion 12 is smoothly connected.
When the positioning followers 23 (ad) move to the circumferential portion 12, no impact or noise is generated. FIG. 5 illustrates this state by moving the positioning follower 23 c relative to the feed wheel 11.

The dimension R from the center of the feed wheel 11 to the center of the drive follower 15 is a half stroke in the X-axis direction of the PPU 1, and the Z-axis stroke is R + Rs
in35. Therefore, as shown in FIG. 1, the stroke trajectory of the PPU 1 has a form in which a perpendicular line of Rsin 35 is attached to both ends of a semicircle having a diameter R. In this embodiment, there is a slight gap between the joint block 22 and the drive follower 15 in the Z-axis direction, and Z
Although the axial movement direction is not locked, the positioning accuracy is stable because an air chuck or a floating air pad is mounted on the head and is always pushed to one side during a pick operation or a place operation. As described above, although one embodiment has been described, the arrangement of the positioning followers 23 (a to d) is inevitably symmetric about the long hole 18, but is not a straight line arrangement as shown in FIG. Become 2
The spacing between the positioning followers can be changed within a certain range.

[0017]

As described above, in the cam-type PPU, the head can be moved up and down at both ends in the X-axis direction while maintaining the X-axis position of the head accurately, and a PPU with high positioning accuracy and high repeatability can be obtained. Can be. Also, X
Unlike the case where a spring or a magnet is used for positioning in the axial direction, vibration due to repulsion does not occur at the time of positioning, so that high-speed operation is possible and durability is high.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a mechanism.

FIG. 2 is a front view showing a part of the section.

FIG. 3 is a front view showing a main part in cross section.

FIG. 4 is a side view showing an operation sequence.

FIG. 5 is a side view for explaining a positional relationship.

FIG. 6 is a side view schematically showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PPU 2 Base plate 3 X-axis slide member 4 Z-axis slide member 5 Mechanism for driving and positioning 6 LM guide 7 Rail 8 Block 9 Stepping motor 10 Output shaft 11 Feed wheel 12 Circumference part 13 Projection part 14 Escape curve part 15 Driving follower 16 Vertical part 17 Horizontal part 18 Slot 19 Z-axis LM guide 20 Block 21 Rail 22 Joint block 23 (ad) Positioning follower

Claims (2)

[Claims] 1. A base plate, an X-axis slide member,
Equipped with a Z-axis slide member and a mechanism for driving and positioning.
The Z-axis slide member is provided movably along the axis, a Z-axis perpendicular to the X-axis is set on the X-axis slide member, and a long hole is provided along the Z-axis. The mechanism for driving and positioning includes a feed wheel, four positioning followers and a drive follower, and the feed wheel is a disc-shaped cam, and is Z from the center of the disc. A projection that reciprocates in a range of a set angle exceeding 90 ° to both sides from the origin set in the axial direction, and has a smooth relief curve connecting the projection and the circumference and the circumference and the projection. It has a symmetrical shape about the axis of the part, and is located between the base plate and the X-axis slide member, the X-axis,
The base plate is supported by a rotation axis in the Y-axis direction that is orthogonal to any of the Z-axes. The four positioning followers are equally spaced two by two on the upper side of the X-axis slide member with the long hole interposed therebetween. And two at the end of the forward rotation of the feed wheel and the end of the reverse rotation of the feed wheel, two of which are simultaneously in contact with the circumferential portion of the feed wheel. The X-axis direction when the feed wheel moves by more than 90 ° to engage with the long hole of the shaft slide member and the joint block at the upper end of the Z-axis slide member to engage the drive follower and the joint block. A pick-and-place device characterized by having a margin for absorbing displacement. 2. The reciprocating rotation range of the feed wheel is about 125 ° from the origin to both sides.
The pick-and-place device according to claim 1.