JP2010269806A - Electronic component carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component carrier that intermittently carries electronic components by securely sucking and holding electronic components even if negative pressure leaks from a certain sucking nozzle that cannot hold an electronic component, resulting in a decrease in negative pressure applied to other sucking nozzles sucking and holding electronic components. <P>SOLUTION: The electronic component carrier 2 includes a rotor 5 intermittently rotated, and sixteen suction nozzles 6 in total, which are arranged on the rotor 5 and sucking and holding electronic components W. In a second position P2 adjacent to a sucking position B, a second detecting means 27 for detecting the presence or absence of an electronic component W is disposed. Based on a detection signal from the second detecting means 27, the control device 13 has information that how many sucking nozzles 6 hold electronic components W. When the total of the sucking nozzles 6 holding electronic components W has decreased to a predetermined number or below, the control means 13 decreases the rotating speed of the rotor 5 via a drive motor 12 and switches to a low speed operation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electronic component conveying device, and more particularly, to an electronic component conveying device configured to intermittently convey an electronic component while adsorbed by a negative pressure.

  Conventionally, an electronic component conveying device that sucks and holds electronic components and intermittently conveys them, and performs processing such as quality inspection of the electronic components at the inspection position provided in the conveying process, and then the electronic components are recessed in the embossed tape. A taping machine to be inserted into the machine is known (for example, Patent Document 1 and Patent Document 2).

JP 2004-238209 A Japanese Patent No. 4057643

Conventional taping machines are required to perform processing at as high a speed as possible. For this reason, it is required to increase the transport speed of the electronic component transport apparatus. The conventional electronic component transport device includes a plurality of suction nozzles that suck and hold electronic components by negative pressure. For high-speed processing, the suction nozzle intermittent transport speed is increased and each suction nozzle is It is necessary to increase the negative pressure. In the conventional general taping machine, the magnitude of the negative pressure of the suction nozzle is determined by the size and ability of the electronic component.
In such a conventional taping machine, if a trouble such as clogging or insufficient supply of electronic components occurs on the part feeder side which is an electronic component supply device, the electronic components may not be supplied to the suction position by the suction nozzle. In this case, since the suction nozzle cannot suck the electronic component and the negative pressure leaks, the negative pressure of the other suction nozzles sucking the electronic component at that time also decreases. As a result, there has been a problem in that the suction position of the electronic component by each suction nozzle is shifted or the electronic component is shaken off from the suction nozzle due to the inertia force when each suction nozzle intermittently conveys the electronic component.
Therefore, the object of the present invention is that even when the suction nozzle cannot hold the electronic component and a negative pressure leak occurs, and the negative pressure acting on the other suction nozzle holding the electronic component is reduced. Another object of the present invention is to provide an electronic component transport apparatus capable of intermittently transporting electronic components while reliably holding them.

In view of the above-described circumstances, the present invention provides a rotating body that is rotated intermittently, a plurality of suction nozzles that are provided on the rotating body to suck and hold electronic components, a supply unit that supplies electronic components, and the rotation Control means for controlling the rotational speed of the body, the electronic parts supplied by the supply means are sucked and held by the suction nozzles, and the electronic parts sucked and held by the suction nozzles are intermittently rotated by the rotating body. In an electronic component transport apparatus that transports one step at a time,
Detection means for detecting whether or not an electronic component is adsorbed to the suction nozzle is provided, and the control means has a predetermined total number of suction nozzles holding the electronic component based on a detection result by the detection means. When the number is less than or equal to several, the rotational speed of the rotating body is reduced more than before and switched to low speed operation.

  According to the above-described configuration, when the total number of suction nozzles for sucking and holding the electronic components becomes equal to or less than the predetermined number, the rotation speed of the rotating body is reduced by the control means and the low speed operation is performed. Even if the negative pressure acting on each suction nozzle decreases, the centrifugal force and inertial force that accompany intermittent movement can be suppressed, and the electronic components can be reliably prevented from being displaced or shaken. It is possible to carry it intermittently while adsorbing and holding.

The top view which shows one Example of this invention. The front view of the principal part which follows the II-II line | wire of FIG. FIG. 3 is a plan view of the fixed plate 15 shown in FIG. 2. The top view of the rotating plate 14 shown in FIG. FIG. 5 is a plan view showing a communication relationship between the communication passages C1 to C15 shown in FIG. 3 and the suction passage 14A shown in FIG. The block diagram of the negative pressure circuit 11 of the electronic component conveying apparatus 2 shown in FIG.

Hereinafter, the present invention will be described with reference to the illustrated embodiments. In FIGS. 1 and 2, reference numeral 1 denotes a taping machine in which an electronic component W is accommodated in a recess of an embossed tape T and packaged. The taping machine 1 causes the embossed tape T to travel intermittently, and the electronic component W is sucked and held at the suction position B by the electronic component transport device 2 and then transported intermittently step by step (1 pitch). In the insertion position A, the electronic components W are sequentially inserted into the respective recesses of the embossed tape T, and then the embossed tape T with the electronic components W inserted is sealed by the heat seal means 4A.
The taping machine 1 according to the present embodiment includes a parts feeder 3 as a supply unit that supplies a large number of electronic components W in a vertical row and then supplies them to the suction position B, and after holding the electronic components W at the suction position B by suction. An electronic component transport device 2 that transports intermittently toward the insertion position A, and a transport and packaging device 4 that intermittently travels the embossed tape T and seals the embossed tape T with heat seal means 4A are provided.

As is conventionally known, the embossed tape T is formed with rectangular recesses that can store the electronic components W at predetermined intervals in the longitudinal direction, and the embossed tape T is intermittently moved in the direction of the arrow by the transport and packaging device 4. When running, the concave portions of the embossed tape T are sequentially carried into the insertion position A.
The electronic component W of this embodiment is a rectangular plate-like LED (light emitting diode), and the LED has a property of being energized only in one direction as conventionally known. Therefore, as will be described in detail later, in the process of transporting the electronic component W intermittently step by step by the electronic component transport device 2, positioning and polarity inspection of the electronic component W are performed, and then the polarity is aligned. Inversion operation and re-positioning, quality determination, subsequent defective product discharge processing, and the like are performed. Only the electronic component W determined to be non-defective is inserted into the recess of the embossed tape T at the insertion position A.

The parts feeder 3 vibrates and aligns a large number of electronic components W. When a large number of electronic components W to be processed are supplied into the parts feeder 3, the electronic parts W are vertically moved by the parts feeder 3. After being aligned in a line, it is supplied to the suction position B.
The conveyance and packaging device 4 is configured to intermittently run the embossed tape T in synchronization with the intermittent conveyance of the electronic component W by the electronic component conveying device 2, whereby each recess of the embossed tape T is intermittently moved. It is carried into the insertion position A. Further, heat seal means 4A is provided downstream of the insertion position A in the traveling direction, and when the embossed tape T after the electronic component W is inserted into the recess is covered with a transparent sheet from above, heat sealing is performed. The transparent sheet is thermally welded to the upper surface of the embossed tape T by means 4A. Furthermore, the conveyance and packaging apparatus 4 includes a winding means 4B at the most downstream position, and the embossed tape T after the recess is sealed by the heat seal means 4A is wound by the winding means 4B. It has become.

Thus, the electronic component transport apparatus 2 of the present embodiment includes a rotating body 5 that is intermittently rotated in the direction of the arrow, and in the illustrated embodiment, 16 suctions are provided around the rotating body 5 at equally spaced positions. A nozzle 6 is arranged. Each suction nozzle 6 is connected to a negative pressure circuit 11 including a vacuum hose 7 to be described later, and each suction nozzle 6 is brought into a negative pressure state via the negative pressure circuit 11, thereby allowing each suction nozzle 6 to The electronic component W can be sucked and held.
The rotating body 5 is intermittently driven at 16 pitches in one rotation in conjunction with the drive motor 12, and is interlocked with intermittent driving for each pitch by the drive motor 12 by lifting means (not shown). Is lifted up and down by a predetermined amount. As a result, each suction nozzle 6 arranged in the rotating body 5 is intermittently moved up and down by a predetermined amount each time from the first position P1 which is the suction position B to the second position P2 to the sixteenth position P16. To be moved to. Thus, the electronic component W can be sucked and held by the suction nozzle 6 lowered at the suction position B (first position P1), and is lowered at the insertion position A (13th position P13). The electronic component W can be inserted into the recess of the embossed tape T by the suction nozzle 6.

  The operation of the drive motor 12 that rotates the rotating body 5 intermittently is controlled by the control means 13, which will be described in detail later. In this embodiment, of the 16 suction nozzles 6, the electronic When the total number of parts holding the component W becomes equal to or less than the predetermined number, the control means 13 reduces the rotational speed of the intermittent rotation of the rotating body 5 via the drive motor 12 and switches to the low speed operation. It has become. Thereby, even if negative pressure leakage occurs, the electronic component W can be reliably held and transported by the suction nozzle 6.

Next, the configuration of the negative pressure circuit 11 will be described. As shown in FIGS. 2 to 5, the negative pressure circuit 11 is connected to a rotating plate 14 that rotates together with the rotating body 5 and a fixed frame (not shown). A fixed plate 15 overlapping with the upper surface of the rotating plate 14 and a plurality of vacuum tubes 7 connected to the rotating plate 14 are provided.
A total of 16 suction passages 14 </ b> A are formed at equal pitches in the circumferential direction of the rotating plate 14, and the lower ends of the suction passages 14 </ b> A opened on the outer peripheral surface of the rotating plate 14 correspond via the vacuum hose 7. It is connected to each suction nozzle 6 at the position. Further, the upper end of each suction passage 14A is opened on the upper surface of the rotating plate 14 (see FIG. 4).
On the other hand, the fixed plate 15 is formed with a total of 16 vertical through holes at equal pitches in the circumferential direction so as to overlap with the opening at the upper end of each suction passage 14 in the rotating plate 14. Among these through holes, through holes at positions corresponding to the first position P1 to the fifteenth position P15 are configured as communication paths C1 to C15. On the other hand, a plug is fitted and closed in the through hole corresponding to the sixteenth position P16, that is, the through hole just before the suction position B (see FIG. 3).

The upper ends of the communication passages C1 to C15 are connected to the tip of a conduit 16 branched into a plurality of portions, and communicate with the negative pressure source 17 through the conduit 16 (see FIG. 6). The negative pressure source 17 is set so as to generate a constant negative pressure. Further, the lower ends of the communication passages C1 to C15 in the fixed plate 15 communicate with any one of the suction passages 14A of the rotation plate 14 regardless of the rotation position of the rotation plate 14 rotated together with the rotating body 5. It has become. That is, when the rotating plate 14 is stopped, the lower ends of the communication paths C1 to C15 of the fixed plate 15 are positioned coaxially with any of the suction paths 14A, and when the rotating plate 14 is moving, the plug is fitted. The other suction passages 14A except for the suction passage 14A at the worn 16th position P16 communicate with any one or two of the communication passages C1 to C15 (see FIG. 5).
As a result, the suction nozzle 6 located at the first position P1 to the fifteenth position P15 when the rotating body 5 is rotated is always in communication with the negative pressure source 17 and the suction nozzle 6 is in a negative pressure state. The suction nozzle 6 located at the sixteenth position P16 before the suction position B (first position P1) is not in communication with the negative pressure source 17 and is not in a negative pressure state.
Instead of the 15 through holes drilled in the fixed plate 15 as the communication paths C1 to C15 as in this embodiment, the C-shaped communication holes in the vertical direction from the communication path C1 to the communication path C15 are used. May be formed.

As shown in FIG. 6, a first electromagnetic switching valve 21 is arranged in the middle of the conduit 16 connecting the communication path C1 corresponding to the first position P1 and the negative pressure source 17, and corresponds to the tenth position P10. A second electromagnetic switching valve 22 is arranged in the middle of the conduit 16 that connects the communicating passage C <b> 10 and the negative pressure source 17. Further, a third electromagnetic switching valve 23 is arranged in the middle of the conduit 16 connecting the communication path C13 corresponding to the thirteenth position P13 (insertion position A) and the negative pressure source 17, and corresponds to the fifteenth position P15. A fourth electromagnetic switching valve 24 is disposed in the middle of the conduit 16 connecting the communicating passage C15 and the negative pressure source 17.
The operations of the first electromagnetic switching valve 21 to the fourth electromagnetic switching valve 24 are controlled by the control means 13. When each of the first electromagnetic switching valve 21 to the fourth electromagnetic switching valve 24 is in the first switching position shown in FIG. 6, the adsorption of the first position P1, the tenth position P10, the thirteenth position P13, and the fifteenth position P15. The nozzle 6 communicates with the negative pressure source 17 and is in a negative pressure state, like the suction nozzle 6 at other positions.
On the other hand, when the control means 13 switches the first electromagnetic switching valve 21 from the first switching position to the second switching position when necessary, the suction nozzle 6 at the suction position B (first position P1) is opened to the atmosphere. At the same time, the conduit 16 at the position of the first electromagnetic valve 21 is closed to prevent negative pressure leakage. Similarly, when the control means 13 switches the third electromagnetic switching valve 23 from the first switching position to the second switching position when necessary, the suction nozzle 6 at the thirteenth position P13 (insertion position A) is opened to the atmosphere. At the same time, the conduit 16 at the position of the third electromagnetic switching valve 23 is closed to prevent negative pressure leakage.

When the control unit 13 switches the second electromagnetic switching valve 22 from the first switching position to the second switching position when necessary, positive pressure air is supplied to the suction nozzle 6 at the tenth position P10, and 2 The conduit 16 at the position of the solenoid valve 21 is closed. Similarly, when the control means 13 switches the fourth electromagnetic switching valve 24 from the first switching position to the second switching position when necessary, positive pressure air is supplied to the suction nozzle 6 at the fifteenth position P15, and the fourth The conduit 16 at the position of the electromagnetic switching valve 24 is closed.
Note that, as described above, the communication passages C1 to C15 formed in the fixed plate 15 are through holes that are drilled independently in the circumferential direction, and when the rotary plate 14 is stopped, the center of the suction passage 14A is the communication passages C1 to C15. Since the suction passage 14A is configured to communicate with at least one of the communication passages C1 to C15 during movement while stopping on the same axis as the center, any of P1, P10, P13, and P15 is open to the atmosphere or positive pressure. Even if the switching is performed, the other communication paths are not affected. Further, even if the order and layout of the inspection are changed in the future, it can be dealt with by adding an electromagnetic valve for switching to the atmosphere or positive pressure without changing the fixed plate 15.

In the present embodiment, the following detection means and positioning means are provided at required positions when each suction nozzle 6 is intermittently moved from the first position P1 to the sixteenth position P16 by one pitch in conjunction with the drive motor 12. The following processing is performed when each suction nozzle 6 is intermittently moved while being lifted and lowered.
As shown in FIGS. 1 and 2, first detection means 26 for detecting whether or not the electronic component W is supplied to the suction position B is disposed at the first position P1 that is the suction position B. Yes. The first detection means 26 detects whether or not the electronic component W is present at the suction position B, and the detection result is input to the control means 13. In this embodiment, when the first detection means 26 detects that the electronic component W is present at the suction position B by the first detection means 26, the control means 13 sets the first electromagnetic switching valve 21 to the first. Leave it in the switching position. For this reason, the electronic component W is sucked and held by the suction nozzle 6 that is lowered at the suction position B.
On the other hand, when it is detected by the first detection means 26 that there is no electronic component W at the suction position B, the control means 13 switches the first electromagnetic switching valve 21 from the first switching position to the second switching position. Switch to position. Accordingly, the suction nozzle 6 at the suction position B (first position P1) is opened to the atmosphere and is not in a negative pressure state.

Next, second detection means 27 for detecting the presence or absence of the electronic component W is arranged at the second position P2, and whether or not the suction nozzle 6 moved to the second position P2 holds the electronic component W is determined. Is detected by the second detection means 27 and the detection result is input to the control means 13.
When the suction nozzle 6 that cannot suck and hold the electronic component W at the suction position B for some reason is positioned at the second position P2, it is detected by the second detection means 27 that there is no electronic component W, and this is the control means 13. To be input. Based on the input from the second detection means 27, the control means 13 recognizes the total number of suction nozzles 6 holding the electronic component W out of all 16 during one rotation of the rotating body 5. It can be done.

Next, the first positioning means 28 having a rectangular frame shape is disposed below the fourth position P4, and when the electronic component W held by the suction nozzle 6 is lowered while being intermittently moved, The electronic component W is inserted into the first positioning means 28 from above. Thus, the posture of the electronic component W is corrected, and the electronic component W held by the suction nozzle 6 is accurately placed in a horizontal state and positioned so that the four sides are positioned in a predetermined direction.
Next, the polarity inspection means 31 is disposed at the fifth position P5. When the electronic component W held by the suction nozzle 6 is carried into the fifth position P5, the polarity inspection means 31 uses the polarity of the electronic component W. Inspection is to be performed. That is, it is detected by the polarity inspection means 31 whether or not the electronic component W held by the suction nozzle 6 is held in a direction in which a predetermined polarity is obtained, and the detection result is input to the control means 13. It has become.

  Next, in the seventh position P7, a reversing unit 32 is disposed that rotates the electronic component W held by the suction nozzle 6 180 degrees on a horizontal plane with the vertical axis of the suction nozzle 6 as the rotation center. When the suction nozzle 6 holding the electronic component W determined to have a polarity failure by the polarity inspection means 31 is carried into the seventh position P7, the control means 13 activates the reversing means 32 at the seventh position P7. ing. As a result, at the seventh position P7, the electronic component W held by the suction nozzle 6 is rotated 180 degrees in the horizontal plane and inverted so as to have the correct polarity. In addition, when the electronic component W determined to have good polarity by the polarity inspection means 31 is carried into the seventh position P7, the reversing means 32 at the seventh position P7 is not operated. .

Next, second positioning means 33 similar to the first positioning means 28 is disposed at the eighth position P8. The second positioning means 33 is arranged assuming that the electronic component W is reversed at the seventh position P7, and the electronic component W held by the suction nozzle 6 is carried into the eighth position P8. When it is lowered, it is positioned by the second positioning means 33 so that the directions are aligned.
Next, at the tenth position P10, a quality inspection means 34 for inspecting whether or not the electronic component W is a non-defective product is disposed. When the electronic component W held by the suction nozzle 6 is carried into the tenth position P10, whether or not it is a non-defective product is inspected by the quality inspection means 34, and the inspection result is input to the control means 13. It has come to be. When the inspection result that the electronic component W is defective is input from the pass / fail inspection means 34 to the control means 13, the control means 13 switches the second electromagnetic switching valve 22 from the first switching position to the second switching position. . Thus, since the suction nozzle 6 at the tenth position P10 is supplied with positive pressure air from the negative pressure state, the defective electronic component W quickly drops from the suction nozzle 6 at the tenth position P10. Yes. In this way, the defective electronic component W is forcibly removed from the suction nozzle 6 at the tenth position P10.

  Next, when the electronic component that is determined to be non-defective by the non-defective inspection unit 34 and is held by the suction nozzle 6 is carried into the insertion position A (13th position P13), the following processing is performed. That is, when the suction nozzle 6 holding the electronic component W is carried into the insertion position A and lowered, the control means 13 switches the third electromagnetic switching valve 23 from the first switching position to the second switching position. As a result, the suction nozzle 6 at the insertion position A is opened to the atmosphere, so that the holding state of the electronic component W by the suction nozzle 6 is released, and the electronic component W is stored in the recess of the embossed tape T. Note that, as described above, the embossed tape T is intermittently traveled by the transport and packaging device 4 in synchronization with the intermittent transport of the electronic component W by the electronic component transport device 2, and the electron held by the suction nozzle 6 is retained. When the component W is lowered, the recess of the embossed tape T is located at the insertion position A.

The fifteenth position P15 is a discharge position for forcibly discharging the electronic component W at the end of production or when switching the type of electronic component W to be processed.
When a forced discharge signal is input to the control unit 13 for the reason of the end of production or the like, the control unit 13 does not process the electronic component W held by the suction nozzle 6 and all the fifteenth positions P15. Until it is discharged.
Further, when the forced discharge signal is input, the control means 13 switches the fourth electromagnetic valve 24 from the first switching position to the second switching position, and supplies positive pressure air to the communication path C15 at the 15th position. Thus, positive pressure air is supplied to the suction nozzle 6 that has reached the fifteenth position P15, and the electronic component W held by suction is forcibly discharged.

  As described above, in the electronic component transport apparatus 2 according to the present embodiment, the rotating body 5 is intermittently rotated in conjunction with the drive motor 12 and moved up and down at every pitch. Accordingly, first, the electronic component W is sucked and held by the suction nozzle 6 at the suction position B, and then the electronic component W held by the suction nozzle 6 is intermittently conveyed by intermittent rotation of the rotating body 5 by one pitch. It has become. Then, in the transport process when the electronic component W held by the suction nozzle 6 is intermittently transported from the first position P1 to the sixteenth position P16, as described above, positioning of the electronic component W, polarity inspection, and required Processing such as reversal operation at the time, quality inspection of the electronic component W, defective product discharge operation, and insertion of the electronic component W into the concave portion of the embossed tape T at the insertion position A is performed.

By the way, there is no problem if the electronic component W is reliably sucked and held by the suction nozzle 6 sequentially at the suction position B, but there are cases where the electronic component W cannot be held by the suction nozzle 6 at the suction position B for some reason. If a plurality of suction nozzles 6 in the 16 suction nozzles 6 arranged on the rotating body 5 do not hold the electronic component W, the suction nozzles 6 that do not hold the electronic component W are open to the atmosphere. As a result, the negative pressure of the suction nozzle 6 holding the electronic component W decreases.
Therefore, in this embodiment, assuming such a case, the second detection means 27 for detecting the presence or absence of the electronic component W is provided at the second position P2, and the control means 13 is a second detection means. Based on the 27 detection signals, the number of the suction nozzles 6 out of the 16 suction nozzles 6 arranged on the rotating body 5 is grasped. When the total number of suction nozzles 6 holding the electronic component W becomes equal to or less than a predetermined number (for example, 7 or less) during the intermittent rotation of the rotating body 5, the control means 13 of the present embodiment The rotational speed of the rotator 5 is decelerated via 12 to switch to a lower speed operation than before.

More specifically, the total number of electronic components W held by the suction nozzle 6 in a state where the rotating body 5 is operated at a high speed capable of intermittently conveying 600 electronic components W per minute via the initial drive motor 12. When the number becomes seven, the control means 13 reduces the rotation speed of the rotating body 5 via the drive motor 12 so as to switch to the low speed operation capable of intermittently conveying 200 electronic components W per minute. It has become.
Control of the operation speed of the rotating body 5 at the start of operation of the electronic component transport apparatus 2 and immediately after that is performed by the control means 13 as follows. That is, first, since there are no electronic components W held by the suction nozzle 6 at the start of operation, the rotating body 5 is operated at a low speed, and then one, two, and three are sequentially picked up at the suction position B. When the number of electronic components W held by the nozzle 6 increases and the number of electronic components W held by the suction nozzle 6 reaches eight, the rotating body 5 is switched to high speed operation. Thereafter, as described above, the operation speed of the rotating body 6 is controlled by the control means 13 in accordance with the total number of electronic components W held by the suction nozzle 6.

  According to such an embodiment, even if the number of suction nozzles 6 that do not hold the electronic component W increases and the negative pressure of the other suction nozzles 6 that hold the electronic component W decreases, Since the suction nozzle 6 is intermittently transported at a low speed, the inertial force and centrifugal force associated with the high-speed intermittent movement are reduced, and the electronic component W can be reliably sucked and held for intermittent transport. Therefore, it is possible to reliably prevent the electronic component W sucked and held by the suction nozzle 6 from being displaced or swung away by the inertial force when intermittently transported, and the suction with reduced negative pressure. Even if it is the nozzle 6, the electronic component conveyance apparatus 2 which can adsorb-hold the electronic component W reliably and can convey intermittently can be provided.

2. Electronic parts conveying device 3. Parts feeder (supply means)
5 ... Rotating body 6 ... Suction nozzle 12 ... Drive motor 13 ... Control means 27 ... Second detection means T ... Embossed tape W ... Electronic components

Claims (1)

A rotating body that rotates intermittently, a plurality of suction nozzles that are provided on the rotating body and suck and hold electronic components, a supply means that supplies electronic components, and a control means that controls the rotational speed of the rotating body The electronic component supplied by the supply means is sucked and held by each suction nozzle, and the electronic component sucked and held by each suction nozzle is conveyed step by step by intermittent rotation of the rotating body. In the transport device,
Detection means for detecting whether or not an electronic component is adsorbed to the suction nozzle is provided, and the control means has a predetermined total number of suction nozzles holding the electronic component based on a detection result by the detection means. An electronic component transport apparatus characterized by switching to a low speed operation by decelerating the rotational speed of the rotating body than before when the number becomes less than a few.

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