JPH0584143B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to a speed detection device in a conveyance device using a linear induction motor. "Prior Art" Conventionally, a single-sided linear induction motor (hereinafter abbreviated as LIM) has been used as a means for transporting objects in a product assembly transport line or the like. As shown in Figure 3 A and B, this type of conveyance device consists of rails 1 arranged along a conveyance path and rails 1 disposed at multiple locations on the conveyance path to generate a traveling magnetic field.
It consists of a stator 2 of the LIM and a pallet 5 which is supported movably along the rail 1 by wheels 3, 3... and has a secondary conductor 4, which serves as a mover of the LIM, attached to its lower surface. By controlling the excitation of the stator 2 as appropriate, thrust is sequentially applied to the pallets 5 to move them to a predetermined position.
It is for transporting objects M placed on a pallet 5. By the way, when detecting the conveyance speed in this type of conveyance device, the following means have conventionally been adopted. That is, the touch roller 6 is provided on the conveyance path,
Detection may be performed using a speed generator or pulse generator attached to the rotating roller shaft of the roller 6, or a plate 7 with a plurality of slits is attached to the pallet 5, and a floodlight is placed between the plates 7. In this method, a light receiver 8a and a light receiver 8b are each fixed on a transport path, and a pulse frequency signal is generated from the light transmitter 8a and optically detected. "Problems to be Solved by the Invention" By the way, all of the above-mentioned conveyance speed detection means have the following problems. That is, since the components for speed detection are arranged in a special space on the conveyance path or on the pallet 5, the installation space for the device becomes large. In the former case, roller 6 and pallet 5
Because there is a risk of slipping between
Particularly when transporting at high speeds, there is a drawback that accurate speed detection cannot be performed, and in the latter case, the emitter 8a or receiver 8b is susceptible to dirt, and if dust adheres to their lenses, detection may not be possible. The drawback was that it disappeared. "Means for solving the problem" By the way, the stator 2 of the linear induction motor has
As shown in FIG. 4, a plurality of grooves 10 are formed along the conveyance direction in order to house the traveling magnetic field generating coils 9. Of these plurality of coil housing grooves 10, the ends of the stator 2 are In the groove 10a located,
Unlike other grooves, the coil 9 is not completely filled in, but an open space G is formed there. Conventionally, this open space G was simply filled with a plug member. The present invention aims to solve the above-mentioned problems by focusing on this bright space and making effective use of the space.The present invention is characterized by the fact that the bright space is connected to an AC power supply. Set the primary coil to be excited, and also install a secondary coil for detecting the amount of change in magnetic flux generated by the primary coil and guided through the secondary conductor. It is at the point where it was set. "Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a longitudinal sectional side view of a conveyance device equipped with a speed detection device according to the present invention. In the figure, reference numeral 11 is a pallet, and a secondary conductor 12 is attached to the lower surface of the pallet 11. Further, reference numeral 13 is a stator provided at predetermined intervals along the passage for conveying the pallet 11.
It is responsible for generating the traveling magnetic field of LIM. A plurality of coil storage grooves 15 are formed in the primary core 14 of the stator 13 along the longitudinal direction (corresponding to the conveying direction). In these grooves 15, three traveling magnetic field generating coils 16 are arranged in pairs.
... are wound every second, and are shifted by one groove, and two
It is stored in layers (see Figure 2). That is, here, the coil 16 is wound in two layers of three-phase all-pitch windings. Here, to provide a supplementary explanation of how these coils 16 are wound, when the grooves 15 are numbered 1, 2, . . . , N sequentially from the left in FIG. 1, the coils 16 are wound as follows.

[Table] With this winding method, Figures 1 and 2
As shown in the figure, coil storage grooves 15a located at both ends of the stator 13 (three from each end)
Only one layer of coils 16 is housed in the space, creating an open space. There are two coils 17 and 18 in this bright space.
are set respectively. The inner and outer coils 17 of these coils are excited by an AC power supply 1
It is a secondary coil, and above it is the secondary conductor 1.
When 2 is located, an eddy current is generated in the secondary conductor 12. In addition, the inner coil 18
is a secondary coil that detects the amount of magnetic flux displacement at that time as a voltage change when the speed of the secondary conductor 12 changes and the eddy current generated in the secondary conductor 12 changes accordingly. A voltmeter 19 is connected to. Note that 20 indicates a plurality of pallet supporting wheels arranged along the conveyance path. Next, the operation of the speed detection device having the above configuration will be explained. First, the primary coil 17 is excited by an AC power source. Then, when the secondary conductor 12 is located above it, an eddy current is generated in the secondary conductor 12, but the electromotive force of this eddy current changes depending on the speed of the secondary conductor 12. This change in the electromotive force of the secondary conductor 12 promotes a change in the amount of magnetic flux that crosses the secondary conductor 12 in the vertical direction, and this displacement in the amount of magnetic flux becomes the magnitude of the electromotive force generated in the secondary coil 18. appears. In other words, the speed change of the secondary conductor 12 is the same as that of the secondary coil 18 if other conditions are kept the same.
This appears as a voltage change. Therefore,
By simply detecting the electromotive voltage generated in the secondary coil 18, the speed of the secondary conductor 12 and the pallet 11 integrated therewith can be determined. In the case of such a speed detection device, since the coil was originally installed in an open space, the installation of the speed detection device increases the size of the entire conveyance device including the speed detection device. No further problems will occur. In addition, compared to using a touch roller as shown in the conventional example above, there is no detection error caused by slips between the roll and the secondary conductor, so it is fully compatible with high-speed detection. can. Furthermore, compared to using optical means as shown in the conventional example, it can be operated satisfactorily even when some dust is attached, and it can be used even in an environment where a large amount of dust is floating. In this embodiment, an example is described in which the traveling magnetic field generating coil 16 is wound in two layers at all nodes of three phases, but the present invention is of course applicable to cases where the coil is wound in other ways. It is. "Effects of the Invention" As explained above, according to the present invention, the coil housing groove located on the end side of the traveling magnetic field generator among the traveling magnetic field generating coil housing grooves provided in the traveling magnetic field generator is clearly visible. A primary coil is excited by an alternating current power supply in a space where the primary coil is excited, and when the magnetic flux generated by the excitation of the primary coil is displaced as the speed of the secondary conductor changes, the amount of magnetic flux displacement is detected. Because it has a configuration in which a secondary coil and a secondary coil are set respectively for the Moreover, there is an effect that there is no problem such as when dust is attached and detection cannot be performed, unlike when optical means are used.

[Brief explanation of drawings]

1 and 2 show one embodiment of the present invention, FIG. 1 is a longitudinal sectional view, FIG. 2 is a view of the stator in the direction of arrows in FIG. 1, and FIG. 3 A and B show conventional speeds. An example of a transport device equipped with a detection device is shown, in which A is a side view, B is a plan view, and FIG. 4 is a diagram illustrating a general traveling magnetic field generating device. 11...Pallet, 12...Secondary side conductor, 13
...Stator (progressive magnetic field generator), 15, 15a
... Coil storage groove, 16 ... Coil for generating a traveling magnetic field, 17 ... Primary side coil, 18 ... Secondary side coil, 19 ... Voltmeter.

Claims (1)

[Scope of Claims] 1. In a conveying device that conveys a pallet on which a secondary conductor is assembled by exciting traveling magnetic field generating devices arranged at appropriate intervals along a conveying path, the traveling magnetic field generating device Among the traveling magnetic field generation coil storage grooves provided, a primary coil excited by an AC power supply and this 1
A speed detection device for a conveying device, characterized in that a secondary coil is provided for detecting the amount of change in magnetic flux generated by the secondary coil and guided through the secondary conductor.