JPH02311160A - Two sides linear motor - Google Patents

Abstract

PURPOSE:To achieve low synchronous speed without causing degradation of characteristic or increase of vibration or noise by employing fractional slot winding for each stator winding. CONSTITUTION:Stator cores 11, 12 are arranged such that the tooth section of one stator core faces with the front face of the slot in the other stator core while shifting each other by half slot. Such fractional slot winding as the number of pole is 4 and the number of slot (q) per pole per phase is 1/2 is employed in the stator windings 13, 14. Coil side of 1 (e.g. the coil side contained in slot #1) belonging to one stator winding 13 is shifted by 3/2 slot pitch from the coil side of another inphase 1 (e.g. the coil side contained in slot #2') belonging to the other stator winding through which current flows in reverse direction. By such arrangement, low synchronous speed can be achieved without causing degradation of characteristic or increase of vibration or noise.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a double-sided linear motor in which a mover is arranged between two stators, and in particular, the stator: A-line configuration. Regarding improvements.

(Prior Art) FIG. 5 shows an example of the arrangement of stator windings in a conventional linear motor of this type. Each core 1 has a large number of slots 2, and three-phase stator windings are arranged in each slot 2 as shown in the figure. where the symbols rU, UJ, rv,'' and r
W and WJ indicate the U-phase, V-phase, and Wt port coil sides, respectively, and "U.

, WJ indicate that current flows in the opposite direction to rU, V, and WJ. These stators are opposed to each other leaving a gap for a movable element (not shown) to pass through, and the toothed portions 1a of both iron cores 1 face each other one-to-one.

(Problem to be Solved by the Invention) However, in this type of linear motor, if the frequency of the power source is constant, the synchronous speed is a constant speed determined by the slot pitch x the number of phases. Therefore, when trying to obtain a particularly low synchronous speed, the number of slots q for each pole should be set to 1, and the width of the teeth 1a of the iron core 1 should be narrowed to make the slot pitch as short as possible. There is a need to. However, if the tooth portion 1a is narrowed, manufacturing problems such as bending of the tooth portion 1a will occur, so this method has a limit.

In order to avoid this problem, it has been considered to construct both stator windings as fractional slot windings, as shown in FIG. In this case, with the iron core 1 having the same slot pitch as that shown in FIG. 5, a synchronous speed half as high as that shown in FIG. 5 can be obtained, and the speed of the mover can be lowered.

However, in the configuration shown in FIG. 6, the magnetomotive force includes many harmonic components. Expressing this as a winding coefficient, the fundamental wave component is 0.886, and even harmonic components such as the 2nd, 4th, 6th, 8th, etc. are also 0.866.
, 3rd, 5th, 7th, and other odd-numbered harmonic components are also o and gee. This causes problems such as not only deterioration of characteristics in terms of thrust, current, etc., but also increase in vibration and noise.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a double-sided linear motor that can obtain a low synchronous speed without deteriorating characteristics or increasing vibration and noise.

[Structure of the Invention] (Means for Solving the Problems) The double-sided linear motor of the present invention has each stator winding arranged in fractional slots such that the number of slots q for each pole and each phase is n/2 (n is an odd number). winding, and 1 belonging to one stator winding.
It is characterized in that the coil side belongs to the other stator winding and is shifted by 3n/2 slot pitch with respect to the other coil side of the same phase through which current flows in the opposite direction.

(Function) With the above configuration, the synchronous speed becomes 1/2 compared to the case where the number of slots q for each pole and each phase is 1. Moreover, of the magnetomotive force generated by the current flowing through each stator winding, odd-order harmonic components remain, but even-order harmonic components cancel each other out and disappear.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 shows the winding arrangement of each stator winding 13, 14 wound around two stator cores 11, 12. Both stator cores 11 and 12 have the same configuration in which seven slots are formed at equal intervals.

These stator cores 11, 12 are in such a relationship that the teeth of one stator core face the front of the slots of the other stator core and are offset from each other by 1/2 slot.

Each stator winding 13, 14 is a fractional slot winding in which the number of poles is 4 and the number of slots q for each pole and each phase is 1/2.

Now, set the slot numbers of the lower stator core 11 from #1 to #
7, and the slot number of the upper stator core 12 is #1'.
~#7', the arrangement of each stator winding 13 and 14 will be described in detail. First, regarding the stator winding 13 wound around the lower stator core 11, the U-phase winding is #1. #2. #4. #
It consists of four coil sides housed in slots 5 and 5, and these are connected in series as shown in Figure 2, with terminals U at both ends.
U2 is formed. On the other hand, regarding the stator winding 14 wound around the upper stator core 12, the U-phase winding is #2'
, #3', #5', #6' slots.
These coil sides are connected as shown in FIG. Ui is formed. Therefore,
Both stator windings 13 and 14 are housed in slots spatially shifted by one slot pitch from each other, and both stator cores 11 and 12 are already arranged shifted by one slot pitch and two slot pitches. Both stator windings 13, 14 are spatially shifted from each other by 3/2 slot pitch. As will be described later, these stator windings 13, 14 are connected to terminals U2. U, is connected to terminal U,,U
1, so when a current flows from the terminal U side, for example, the current flows through each coil side in the direction shown by the arrow in FIGS. 2 and 3. As a result, one coil side belonging to one stator winding 13 (for example, the coil side housed in #1) belongs to the other stator winding 14 and is connected to another side of the same phase in which current flows in the opposite direction. side of the coil (e.g. #2
It is supposed to be shifted by 3/2 slot pitch with respect to the coil side housed in '). In addition, in Fig. 1, the symbol r
The coil side through which a current flows in the opposite direction to the coil side of UJ is indicated using the symbol rUJ. Furthermore, the V-phase and W-phase stator windings are wound in the same manner from the U-phase winding with only one slot pitch shift, as shown in FIGS. 1 to 3. The windings of each phase are connected in a 1×Y connection as shown in FIG. 4 to a three-phase power source (not shown).

Now, the magnetomotive force distribution H1ltml when the stator winding 13 is connected to a three-phase power source is expressed by the following equation.

H13Lll” ff Kcos (w t-I
X) Here, X: Coordinate of the gap expressed in electrical angle (#
The center of #1 and #2 is defined as x-0, and the direction in which the slot number increases is defined as positive (expressed in electrical angle).

1,: Harmonic order (integer excluding multiples of 3).

ω: Angular velocity of three-phase power supply.

The winding coefficient for the K-order harmonic is 0.866 for all values of (other than multiples of 3).

t: Elapsed time (seconds) from the point when the U-phase current is at its maximum.

On the other hand, the magnetomotive force distribution H,4, when the stator winding 14 is connected to a three-phase power source is expressed by the following equation.

H14Lml ” f, (-T)Kcos(ωL-'
, (x-yr) 1Here, if the harmonic order l is an even number, 1(,4,,,ccΣ(--T-)K cos
(ωt-(x), and if the harmonic order l is an odd number, HI3.,,ocΣ Kcos(ωt-1,x)
It becomes 1 knife. Therefore, the magnetomotive force distribution in the air gap between both fixed T is H1
Since it is expressed as the sum of □1 and HI3°, even-numbered components cancel each other out and disappear. In addition, the ratio of odd-order components to the fundamental wave component is constant,
All winding coefficients are 0.886. This value is the same as that of the q-1 stator winding shown in FIG.

According to this embodiment, since fractional slot winding is adopted, the synchronous speed can be reduced to 1/2 compared to the conventional structure shown in FIG. 5 while using the same stator core. can. Moreover, although it is a fractional slot winding, unlike the structure shown in Figure 6, harmonic components can be halved, so there is no reduction in characteristics such as thrust and current, and vibration and noise are sufficiently suppressed. be able to.

Note that the implementation structure of the present invention is not limited to the above-described embodiments, and can be implemented with various changes without departing from the gist, such as the following changes.

(a) In the stator winding, the number of slots q for each pole and each phase is 1/2
Not limited to 3/2.5/2. It can be widely applied to fractional slot windings such as n/2 (n is an odd number).

(b) In the above embodiment, a case where a stator with four poles is constructed is shown, but the present invention is not limited to this, and can be similarly applied to stators with two poles, six poles, eight poles, etc.

(c) The stator windings 13 and 14 are not necessarily connected in series, but may be connected in parallel. Alternatively, a Δ connection may be used.

[Effects of the Invention] As described above, the double-sided linear motor of the present invention has the excellent effect of being able to obtain a low synchronous speed without deteriorating characteristics or increasing vibration and noise.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, and FIG. 1 is a winding arrangement diagram of the stator winding shown together with the stator core.
The figure is a developed view of one stator winding, Figure 3 is a developed view of the other stator winding, Figure 4 is a connection diagram of the stator winding, and Figure 5 is equivalent to Figure 1 showing a conventional example. 6 is a diagram corresponding to FIG. 1 showing an example in which fractional slot winding is adopted for the stator winding. In the drawing, 11.12 is a stator core, and 13.14 is a stator winding. Agent: Patent Attorney Noriyuki Chika
Ken Maru No. 1 U+ V+ V/
+ U2 V2 W2 W4U4 V
4 W3 U3 V3 Fig. 2 Fig. 3
Figure M4

Claims (1)

[Claims] In a device consisting of one or two stators facing each other at a distance, the stator winding of the stator is fractionally slot wound so that the number of slots q for each pole and each phase is n/2 (n is an odd number). In addition, one coil side belonging to one stator winding has a slot pitch of 3n/2 with respect to another coil side of the same phase that belongs to the other stator winding and in which current flows in the opposite direction. A double-sided linear motor characterized by being configured to shift.