JP2691707B2 - Induction type linear motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction type linear motor that stops a moving body traveling on a conveyance path at a destination. 2. Description of the Related Art A transfer device for a moving body that uses an induction linear motor as a drive source includes a plurality of stators provided along a track and provided with three-phase windings, and a reaction plate provided on the moving body. The induction type linear induction motor (hereinafter referred to as L1M) is composed of the stator and the reaction plate. By driving L1M, the wheels provided on the moving body roll on the track, and the moving body travels to the destination. Then, when the vehicle approaches the destination, the energization in the traveling direction of the three-phase winding of the stator provided in the destination is turned off, and the energization is turned on in the opposite direction to reversely excite the reaction plate to the traveling direction. It is configured to generate thrust in the opposite direction and stop at the destination. Various means such as installation of another type of coil and provision of mechanical means have been implemented in order to increase the stopping accuracy. On the other hand, when designing the L1M that is the drive source of the transfer device, unlike a normal electric motor, it is performed as follows, for example, in order to obtain a constant thrust. That is, in designing the transfer device, the horizontal width and the vertical width of the moving body are determined according to the size of the transported object, and then the optimum specification L1M for driving is determined. Next, the length of the reaction plate for stopping the fixed point, which is the destination, is determined by the opposite excitation of the three-phase winding. In general, the length of the reaction plate in the traveling direction is set to be equal to or longer than the length of the stator core in order to obtain a large thrust at the time of starting and accelerating the L1M. Problems to be Solved by the Invention However, since the braking force obtained with the set length of the reaction plate described above is large, a problem such as stopping before the fixed point occurs, which may make it difficult to stop the fixed point. On the contrary, if the set length of the reaction plate is shortened, the braking force obtained is small, so that the traveling energy cannot be absorbed in a short time and the fixed point is passed. Therefore, it takes a long time for the moving body to repeatedly swing and stop. Further, in order to determine the length of the reaction plate in the traveling direction, since trial adjustment is required in consideration of the thrust force and the braking force of L1M as described above, there is a problem that the cost therefor increases. Therefore, the invention according to claim 1 of the present invention provides an induction type linear motor that efficiently obtains a fixed point stop at a destination by setting a reference for setting the length of the reaction plate in the traveling direction. Has an aim. Means for Solving the Problems In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention is an induction type linear motor that stops a moving body traveling on a conveyance path at a destination. The stator provided on the ground is an iron core having N slots of (multiple of 6 + 3) and (N + 1) teeth, an I-group winding and an The reaction plate provided on the moving body has a length Lm in the traveling direction, which is Lm ≦ P (N−7) ( However, P is set to the length of a set of adjacent slots and teeth of the stator core), and the group I winding and the group II winding are U and V, which are windings that are wound in layers. , W, each slot is shifted in the same direction by one slot pitch, and U of the group I winding is
U-phase, V-phase, W-phase of group II winding for each phase, V-phase, W-phase winding
The respective phase windings are sequentially arranged so as to overlap the same slot, and by applying symmetrical three-phase alternating voltages of opposite phases to the group I winding and the group II winding, the amplitude of the magnetic field is increased. Is symmetric with respect to the center of the iron core, and the magnetic fields are excited so that the traveling directions of the magnetic fields face each other. Embodiment An embodiment of an induction type linear motor (hereinafter referred to as L1M) according to the present invention will be described below with reference to the drawings. Fig. 1 is an explanatory diagram of the principle of L1M, Fig. 2 is a connection diagram of the three-phase winding of the stator, Fig. 3 is a waveform diagram of the three-phase AC voltage applied to the three-phase winding, and Fig. 4 is three. In the vector diagram of the phase alternating voltage, FIG. 4 (A) shows the voltage applied to the I group in FIG. 2, and FIG. 4 (B) shows the voltage applied to the II group. FIG. 5 (A) is a sectional view showing a state where the winding shown in FIG. 2 is housed in a slot, and FIG. 5 (B) is a group I and a group II.
Waveform diagram showing the state of the magnetic field generated by the group winding corresponding to the time transition T1 to T6 of one cycle, and FIG. 6 is a composite diagram of the magnetic fields of the I group and the II group shown in FIG. is there. In FIG. 1, A is a moving body that travels on a conveyance path (not shown) by the thrust of an induction type linear motor, and a reaction plate L is provided on the lower surface of the moving body A. B is a stator arranged at the destination. The reaction plate L and the stator A face each other with a predetermined gap, and L1M is constituted by both. C shown in the figure represents a destination where the mobile unit A should stop. The L1M stator core has N slots of (multiple of 6 + 3) and (N + 1) teeth. The slots are inscribed in the iron core of the stator B orthogonally to the traveling direction of the moving body A, and are 6 × 2 + 3 in FIGS. 2 and 5 (A).
= 15 are shown. The three-phase winding has a group I winding and a group II winding which are provided on the iron core and have the same structure. In this embodiment, the group I and group II windings are shown in FIGS.
As shown in FIG. 6A, each winding is composed of 6 windings (a multiple of 3). The winding C11 forming the U1 phase of the I-th group winding is overlapped with a predetermined number of turns at a pitch across three adjacent teeth t2, t3, t4, and is fitted into the slots S1, S4. In addition, the winding C12 that constitutes the V1 phase of the I group winding is in slots S2 and S5 that are offset by one slot pitch in the same direction, and the winding C13 that constitutes the W1 phase of the I group winding is the same as above. , Slot S3
And S6 respectively. The starting end and the terminating end of these windings are connected in three phases to form a group I winding. The windings C21, C26 of the group II windings are also slot S according to the above.
7 to S15, and is connected to three phases separately from the first group winding to form a second group winding independent of the first group winding. Each three-phase power supply has a different phase rotation. It is designed to be connected to. That is, as shown in FIG. 5 (A), the U phase of the group I winding, V
U-phase and V-phase of the group II winding on each of the C-phase and W-phase coils C11 to C16
Phase C and W phase coils C21 to C26 are located in the same slot, upper and lower 2
Sequentially arranged in layers. In the figure, slots S4 ~
The windings are fitted in the upper and lower two layers of S12, but the lower layer and slots of slots S1 to S3 located at both ends of the iron core
A space (not shown) is fitted in the upper layers of S13 to S15 to fix the winding. Further, the stator B is arranged so that the center of the fixed core is aligned with the destination C. Then, three-phase AC voltages U1, V1, W1 and U2, V2, W2 having vectors as shown in FIG. 4 are applied to the three-phase winding. T1 to T7 in FIG. 3 represent changes in the three-phase AC voltage at each time when one cycle is divided into six equal parts. Hereinafter, the action between the reaction plate and the magnetic field according to the present invention will be described. The 12 windings of group I and group II shown in FIG.
As shown in Fig. (A), the stator core is fitted in 15 slots, and the windings of the I-group and the II-group have the opposite phase relationships shown in Figs. 4 (A) and 4 (B), respectively. When a certain three-phase AC voltage is applied and counter-excited, the state of the magnetic field at each time T1 to T6 shown in FIG. 3 becomes as shown by a solid line in FIG. 5B and by a broken line b. A magnetic field obtained by combining a and b is shown in FIG. As shown in FIG. 5, 4 slots on the left end side of the group I winding
Since S1 to S4 and the three slots S13 to S14 at the right end of the group II winding each have one layer of winding housed in the slot,
The magnetic field generated in the one-layer winding exhibits a special imbalance, and the end effect occurs. However, the right end side of the group I winding and the left end side of the group II winding,
That is, although the end effect is generated near the center of each opposing magnetic field, the end effects are combined with each other to form a complete alternating magnetic field as shown in FIG. 6 (B). Therefore, the end effect near the center of the opposing magnetic field, which was originally unbalanced, is completely canceled and eliminated. Then, the two-layer winding partial teeth t5 to t13 of the group I and group II windings
In the meantime, that is, in the symmetrical alternating magnetic field range, an alternating magnetic field is formed. That is, when viewed individually, in the group I and group II windings, the traveling magnetic fields are opposed to each other, but as a whole, the magnetic fields at points equidistant from the center of magnetic pole symmetry are always changing symmetrically. Assuming that the length of the reaction plate L of the moving body A in the traveling direction is within the length corresponding to the range of the teeth t5 and t13 of the iron core of the stator B, when the moving body reaches the vicinity of the destination C, The stop braking force to the central portion of the iron core is generated while being out of the range of the end effect generated between the teeth t1 to t4 and the teeth t10 to t15 described above. Therefore, the moving body is set as the destination C, and the tooth t9 is set in this embodiment.
You can always stop in a stable position. In the above embodiment, the distance between the teeth t5 and the teeth t13 is 8 times the slot pitch. However, the slot pitch P refers to the length of a pair of adjacent slots and teeth of the stator core. If the slot pitch is P and the number of slots is N, then N =
Therefore, the length Lm of the reaction plate L in the traveling direction is Lm ≦ (N−7) × P = 8 × P for the stator core having the three-phase winding described above. The effect can be obtained. Although the above embodiment has described the case where N = 15, generally, the number of windings of one group is a multiple of 3, and the total number of windings of three-phase windings is a multiple of 3. And (6 multiples) windings (6
It is set in the iron core having N slots, which is a multiple of +3), and the length Lm of the reaction plate is Lm ≦ P (N−7). The above relation is the same even when the number of windings (a multiple of 3) and the number of slots are changed from (a multiple of 6 + 3) with respect to a stator core having a three-phase winding wound as described above. The number of slots and the number of windings shown in the above embodiment are not limited. If the length of Lm is too short, a fixed point position is possible, but since the time to stop is long,
Practically, it is desirable that the length be close to the above dimension. EFFECTS OF THE INVENTION As described above, the induction linear motor according to the present invention is an induction type linear motor that stops a moving body traveling on a conveyance path at a destination, and the stator provided at the destination is (6 N slots consisting of multiples +3) and (N +
1) A three-phase winding having an iron core having a plurality of teeth and a group I winding and a group II winding, which are provided on the iron core and have the same structure, is provided. The length Lm of the reaction plate provided in the running direction is P
Then, Lm ≦ P (N−7) (where P is the length of a pair of adjacent slots and teeth of the stator core) is set, and the group I winding and the group II winding are set. As for the windings, the windings wound in layers are shifted in the same direction by one slot pitch for each of the U, V, and W phases, and the U of the group I winding is used.
U-phase, V-phase, W-phase of group II winding for each phase, V-phase, W-phase winding
The respective phase windings are sequentially arranged so as to overlap with the same slot, and by applying symmetrical three-phase alternating voltages of opposite phases to the group I winding and the group II winding, the amplitude of the magnetic field is increased. Is symmetric with respect to the center of the iron core, and the magnetic fields are excited so that the traveling directions of the magnetic fields face each other. Therefore, the setting standard can be obtained for the length in the traveling direction of the reaction plate when planning and designing the transport device using the L1M, and the product is standardized. Therefore, the planning and designing time can be shortened as compared with the conventional one, and costly trial manufacture and adjustment are not required, and a desired fixed point stop can be efficiently obtained. Furthermore, since it is possible to accurately and stably stop the moving body at the destination without the need for installing another kind of coil for stopping or mechanical stopping means required in the prior art,
It is extremely important to make contributions in terms of standards and manufacturing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of the principle of LIM, FIG. 2 is a connection diagram of a three-phase winding of a stator, and FIG. 3 is a waveform of a three-phase AC voltage applied to the three-phase winding. Figures and 4 are vector diagrams of three-phase AC voltage.
FIG. 4A shows the voltage applied to the I group in FIG. 2, and FIG. 4B shows the voltage applied to the II group. FIG. 5 (A) is a sectional view showing the winding shown in FIG. 2 in a slot, and FIG. 5 (B) is a group I and a group II.
Waveform diagram showing the state of the magnetic field generated by the windings of the group corresponding to the time transitions T1 to T6 of one cycle, and FIG. 6 is a composite diagram of the magnetic fields of the group I and group II shown in FIG. Is. A: Moving object, B: Stator, C: Destination, C11-C1
6, C21 to C26 …… winding, S1 to S15 …… slot, t1 to t16
……tooth

Claims (1)

(57) [Claims] An induction linear motor for stopping a moving body traveling on a conveyance path at a destination, wherein a stator provided at the destination has N slots of (multiple of 6 + 3) and (N +
1) A three-phase winding having an iron core having a number of teeth and a group I winding and a group II winding having the same structure and provided on the iron core is provided. The length Lm of the reaction plate provided in the running direction is P
Then, Lm ≦ P (N−7) (where P is the length of a pair of adjacent slots and teeth of the stator core) is set, and the group I winding and the group II winding are set. As for the windings, the windings wound in layers are shifted in the same direction by one slot pitch for each of the U, V, and W phases, and the U of the group I winding is used.
U-phase, V-phase, W-phase of group II winding for each phase, V-phase, W-phase winding
The respective phase windings are sequentially arranged so as to overlap with the same slot, and by applying symmetrical three-phase alternating voltages of opposite phases to the group I winding and the group II winding, the amplitude of the magnetic field is increased. Is symmetric with respect to the center of the iron core, and the magnetic fields are excited in directions in which the traveling directions of the magnetic fields face each other.