JP5927643B2 - Pickup unit - Google Patents

Description

  The present invention relates to a pickup unit used in a loading unit of an automatic assembly line.

In automatic assembly line loading (part conveyance assembly, etc.), a pick-up unit may be attached to the tip of a PPU (pick and place unit) or robot arm.
The pick-up unit has a work suction part such as a suction pad at the tip, which picks up the work, lifts it, moves it to a predetermined position, then lowers it, performs the operation of releasing the suction at the set predetermined position, and removes the work Place it at the desired position. This replacement operation is required to be fast and highly accurate. In order to increase the speed and repeatability, it is necessary to consider the inertia when moving the pickup unit.

  Many pickup units include a main body portion and a moving portion having a work suction portion at the tip, and the moving portion is driven with respect to the main body portion by air pressure. However, in the case of air, there is a vibration unique to the air pressure mechanism due to the elasticity of the compressed air when the moving part starts and stops moving, and when the operation becomes high speed, the agility and certainty of the operation are unsatisfactory.

  FIG. 4 discloses a part corresponding to a pickup unit as referred to in this application as a conventional example at the time of this application, which is a part of a horizontal handler. This portion enables the guide A4 to move up and down (in the vertical axis direction of the cylinder) via the linear guide A3 to the cylinder A1, and connects the lower end of the piston rod of the cylinder A1 and the linear guide A3 to guide A4 by air pressure. Drive up and down. A suction portion by suction air is provided on the lower surface portion of the guide A4.

  The pickup unit includes a guide A4 and a piston rod through the cylinder A1 and the linear guide A3, and the axis of the cylinder A1 (that is, the axis of the piston rod), the axis of the guide A4, and the axis when the suction part moves up and down. Three (trajectories) are juxtaposed in parallel. For this reason, the width of the pickup unit increases in the direction in which the axes are juxtaposed, and it is difficult to reduce the size. In addition, since stroke applying means such as a cylinder and a piston become large, inertia at the time of starting and stopping to move the suction portion is large, and it is difficult to obtain a high-speed and accurate pickup operation. In addition, since the piston rod of the cylinder is driven by air pressure, there is a lack of agility in operation.

FIG. 3 attached to the present application shows a typical structure of a pickup unit using air pressure. The pickup unit 1 generally includes a cylinder 2, a piston 3, and a suction nozzle 4 attached to the tip of the piston 3. The piston 3 is pushed downward from the upper initial position by the air pressure supplied from the port 5 inside the cylinder 2, and is returned to the initial position by the compression spring 6. Air pressure (adsorption) is supplied to the nozzle 4 from a port 8 provided at the tip of a piston rod 7 via an air passage 9. Ports 5 and 8 are connected to a valve device 11 under the control of the control device 10, and air pressure is supplied and discharged under a certain algorithm.
The rod 7 of the piston 3 is linearly guided by a guide 12 arranged in parallel with the axis of the rod 7. The pickup unit 1 is attached to a head 13 on the P & P (Pickup and Place) side that operates the pickup unit 1.

  In this structure, since the piston 3 is driven by the cooperation of the air pressure and the compression spring, the operation is likely to be unstable when the suction nozzle 4 is started and stopped at the upper end and the lower end. In addition, since the port 8 for the suction nozzle 4 is formed at the tip of the rod 7 that moves up and down at high speed, the air pressure tube connected to the port 8 is also vigorously shaken to determine the positioning accuracy when determining the suction position. It is hard to raise.

  The holding and transporting mechanism of Patent Document 2 includes a holding unit driving mechanism 40 (a reference is a reference in this document), a movable holding means 10, a turntable 31, and a process processing mechanism 20. The holding unit drive mechanism 40 includes a motor 41, a cylindrical cam 43, and a rod 44, and presses the movable holding means 10 conveyed by the turntable 31 from above to move the suction nozzle 11 at the lower end of the movable holding means to a lower process processing mechanism. It is a structure to move toward 20.

The holding part drive mechanism 40 rotates the cylindrical cam 43 with a motor 41 (via a speed reduction mechanism), and drives the movable holding means 10 and the suction nozzle 11 up and down with a rod 44 whose upper end is in contact with the cam surface. The cylindrical cam 43 is a kind of inclined plate cam that uses a cam curve on its lower cam surface.
In this holding and conveying mechanism, the holding unit driving mechanism 40 and the movable holding unit 10 are separated, and the movable holding unit 10 is carried by the turntable 31 with respect to the holding unit driving mechanism 40 at a fixed position, so that the predetermined moving unit is movable. Opposite to the holding means 10. In addition, the supply path | route of the suction air which supplies air pressure to the suction nozzle 11 is abbreviate | omitted.

  As described above, the holding and conveying mechanism of Patent Document 2 uses the cylindrical cam 43, but the portion corresponding to the holding portion driving mechanism 40 and the portion corresponding to the movable holding means 10 are integrated as in the pickup unit. It is not assembled.

JP 2001-212786 A JP 2007-35745 A

  Providing a pickup unit that is easy to miniaturize, has low inertia when starting and stopping, can perform pickup operation quickly and accurately, and is agile.

  Automatic assembly line loading can be performed at high speed.

The front view which showed the Example in the partial cross section. The cam curve of the cam which an Example employ | adopts. The front view which showed the prior art example schematically.

In FIG. 1, reference numeral 21 denotes a pickup unit according to the invention of this application.
In this embodiment, the pickup unit 21 is attached to the tip of a head 22 of a P & P (not shown) or industrial robot with the operating direction being up and down.
The pickup unit 21 includes a machine body 23 (main body portion), a slide shaft 24 (moving portion), and a cylindrical groove cam 25 in an arrangement in which the slide shaft 24 is downward and the cylindrical groove cam 25 is upward. In these, the central axis 26 in the sliding direction of the slide shaft 24 and the central axis of rotation of the cylindrical groove cam 25 are made to coincide with the main axis 26 along one main axis 26 set in the machine body 23.

The slide shaft 24 is guided so as to be movable in the vertical direction along the main axis 26 with respect to the machine body 23 and has a suction nozzle 27 at the lower end. Air pressure (for suction) is supplied to the suction nozzle 27 from a port 28 provided in the lower part of the machine body 23 through an air passage 29 inside the slide shaft 24. The port 28 passes through the inside of the machine body 23, and an air channel 30 that is wide in the vertical direction is formed around the slide shaft 24 on the peripheral surface of the slide shaft 24 corresponding to the port 28. The vertical width w of the air channel 30 is such a size that the port 28 side at a fixed position and the air passage 29 are always in communication regardless of the movement of the slide shaft 24. Reference numeral 31 denotes a sealing material, which is disposed between the inner surface of the guide portion by the machine body 23 and the surface of the slide shaft.

  The cylindrical groove cam 25 is formed with a spiral cam groove 32 on the peripheral surface, and is supported on the upper end portion of the machine body 23 via a bearing, and the machine body centering on the rotation axis along the main axis 26. The shaft 23 is rotatably supported at a fixed position 23 and is driven to rotate by a stepping motor 33 indicated by a broken line. Reference numeral 34 denotes a passive shaft of the cylindrical groove cam 25 and is connected to the stepping motor 33.

The cylindrical groove cam 25 and the slide shaft 24 are operatively coupled via a joint portion 35 and a cam follower 36. That is, in this embodiment, the upper end of the slide shaft 24 is provided with a connecting portion 37 extending from one place on the circumference in the direction of the cylindrical groove cam 25, and the cam follower 36 is perpendicular to the main axis 26 at the upper end portion. It is arranged through. One end of the cam follower 36 is guided to the cam groove 32 of the cylindrical groove cam 25 via a roller 38, and the other end is guided to a linear guide hole 40 (U-shaped) provided on the peripheral surface of the machine body 23 via a roller 39. Guided by a groove).
The linear guide hole 40 is formed in the direction of the main axis 26 and has a dimension in the vertical direction that is sufficiently longer than the stroke of the slide shaft 24 determined by the cylindrical groove cam 25.
The cam curve of the cylindrical groove cam 25 is assumed to be almost a sine curve as shown in FIG.

  The pickup unit 21 operates as follows. Although not shown in the figure, the driving / stopping of the stepping motor 33 and the supply of air pressure to the port 28 are under the control of the control device as in the prior art. The control device may control the pickup unit 21 in connection with the operation of the P & P to which the pickup unit 21 is attached or the robot.

The suction nozzle 27 is positioned by the P & P (head 22) so as to be positioned immediately above the workpiece (the tip of the suction nozzle 27 is at the position of the upper chain line 41).
The stepping motor 33 is driven to rotate the cylindrical groove cam 25 by 180 °.
The cam follower 36 linearly moves downward with one end roller 38 guided by the cam groove 32 and the other end roller 39 guided by the straight guide hole 40. Since the cam follower 36 penetrates the joint portion 35, the slide shaft 24 moves to the lower end via the joint portion 35, and the suction nozzle 27 is in contact with the upper surface of the work (position of the lower chain line 42). At this time, the cam follower 36 receives a moment to rotate the joint portion 35 from the cylindrical groove cam 25 due to friction between the roller 38 and the groove wall of the cam groove 32, but the other end portion is guided to the linear guide hole 40. So this moment is suppressed. Thereby, the inconvenience that the slide shaft 24 receives a rotational load can be solved.

When air pressure is supplied to the suction nozzle 27 and the work is sucked, the stepping motor 33 further rotates the cylindrical groove cam 25 by 180 ° to lift the work upward.
Next, the P & P is actuated to convey the workpiece to the set position, and at that position, the cylindrical groove cam 25 is rotated 180 ° again, and the workpiece is placed at the target position. When the air pressure is released and the workpiece is released, the cylindrical groove cam 25 is further rotated so that the tip of the suction nozzle 27 is positioned at the upper chain line 41. This completes the pickup operation for one cycle. This operation is repeated.

In this embodiment, the following effects are exhibited.
A slide shaft 24 and a cylindrical groove cam 25 are arranged along one main axis 26 set in the machine body 23, and a slide direction center axis of the slide shaft 24 and a rotation center axis of the cylindrical groove cam 25 are made to coincide with the main axis 26. Because it is arranged, twisting and moment are unlikely to occur in the power transmission path during operation, and the operation can be speeded up easily. In addition, since there is little trouble such as the tip of the slide shaft 24 swinging, accurate positioning can be performed.
Further, since the main members related to the operation are along one main axis 26, there is no member projecting sideways, and the airframe 23 can be easily made thin and light. For this reason, it can be set as the pick-up unit with a small inertia at the time of starting / stopping.
Furthermore, by incorporating the sealing material 31, it is possible to eliminate backlash due to a slight gap between the slide shaft 24 and the machine body 23, and to ensure the stability of repeated operations.

As shown in FIG. 2, the cam curve of the cylindrical groove cam 25 can be made almost like a sine curve, so that the slide shaft 24 is shockless when starting and stopping when the slide shaft 24 is at the upper end position or the lower end position of the stroke. It is possible to prevent the workpiece from being damaged or removed. In addition, since it is a vertical mechanism using a cam, there is no disadvantageous cushioning at the time of starting and stopping as in the case of air pressure, and high speed and accurate repeat accuracy can be obtained.
Since the cam follower 36 is integrally formed with one end portion guided by the cam groove 32 of the cylindrical groove cam 25 and the other end portion guided by the linear guide hole 40, the rotational load when the cylindrical groove cam 25 rotates is linear guide. The slide shaft 24 is canceled by the engagement with the hole 40, and no rotational load is applied to the slide shaft 24. For this reason, accurate positioning of the suction nozzle 27 can be easily performed.

  Instead of the linear guide hole 40, the guide (12) can be arranged in parallel with the rod (7) in order to stop the rotation of the rod (7) as in the conventional example of FIG. Since the mounting position of the guide (12) is the tip of the rod, the rotational load acting on the rod tends to reach the tip of the rod, that is, the suction nozzle. In such a case, the guide (12) is close to the axis of the rod (7), and the guide (12) has a low ability to suppress the rotation of the rod. On the other hand, in the embodiment of the present application, the cam follower 36 can be arranged at the base of the slide shaft 24, so that the influence of the rotation of the cylindrical groove cam 25 can be suppressed at the base of the slide shaft 24. For this reason, even if there is a rotational load acting on the slide shaft 24, the tip suction nozzle 27 is hardly affected. Moreover, since the distance between the one end (roller 38) and the other end (roller 39) of the cam follower 36 can be increased, the ability to suppress the rotational load of the slide shaft 24 is high.

The embodiment has been described above.
In the embodiment, since the pickup unit 21 is arranged in the vertical direction, the arrangement of members and the direction of operation are set up and down, but for convenience of explanation, it may be left and right or other directions.
The joint portion 35 is not formed integrally with the upper end of the slide shaft 24 as in the embodiment described above, but is a separate member having a portion attached to the slide shaft 24 and a portion extending in the direction of the cylindrical groove cam 25. You can also.
The cam curve of the cam groove 32 in the cylindrical groove cam 25 may be one that makes one stroke of the slide shaft 24 at 180 °, or may correspond to the reciprocating rotation of the cylindrical groove cam 25.

21 Pickup unit 22 Head (P & P or robot)
23 Machine body 24 Slide shaft 25 Cylindrical groove cam 26 Main axis 27 Adsorption nozzle 28 Port 29 Air passage 30 Air channel 31 Sealing material 32 Cam groove 33 Stepping motor 34 Passive shaft 35 Joint part 36 Cam follower 37 Connecting part 38 Roller 39 Roller 40 Linear guide Hole 41 Upper chain line 42 Lower chain line

Claims (3)

A pickup unit used to lift and place a workpiece at a desired position ,
The slide shaft and cylindrical groove cam along one main axis set in the pickup unit body align the slide axis of the slide shaft and the rotation center axis of the cylindrical groove cam with the main axis, and move the slide shaft downward. , The cylindrical groove cam is arranged above,
The slide shaft is guided by the machine body in the vertical direction, is provided with a suction nozzle at the lower end, and is provided with a connecting portion extending from one place on the circumference of the upper end toward the cylindrical groove cam,
A cam follower is disposed through the upper end of the connecting portion in a direction perpendicular to the main axis,
The cylindrical groove cam is formed with a helical cam groove on the peripheral surface and is rotatably supported at a fixed position of the airframe.
The machine body, slide shaft, and cylindrical groove cam are configured such that one end of the cam follower is guided to the cam groove of the cylindrical groove cam and the other end is guided to a linear guide hole in the vertical direction along the main axis provided on the peripheral surface of the machine body. Combined,
A pick-up unit characterized in that a rotational driving force is transmitted to a cylindrical groove cam, and a slide shaft is displaced in the main axis direction via the cam follower and a connecting portion as the cylindrical groove cam rotates.   The pickup unit according to claim 1, wherein the joint portion is constituted by a separate member attached to the slide shaft.   3. The pickup unit according to claim 1, wherein a stepping motor is attached to an upper end of the machine body, and a rotational driving force is transmitted from the stepping motor to the cylindrical groove cam.

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