JPS6240934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Recent electronic control technology has been remarkable due to the development of computers. As terminal equipment for utilizing this control technology, various types of equipment with power sources, which gave rise to the term mechatronics, have inevitably been developed.

As this power source, stepping motors, servo motors, etc. are generally used, and new products of these are actively being developed.

The present invention relates to a laminated core for an electric motor including such a servo motor for control equipment, and will be described in detail below with reference to the drawings.

The first and second stator cores of conventional servo motors
As shown in the figure. FIG. 1 is a plan view, and FIG. 2 is a sectional view thereof. As shown in FIGS. 1 and 2, for example, a four-pole stator core for a servo motor is composed of a magnet 1 and a laminated core 2. A hole 3 in which an armature 4 is installed is provided in the center of the iron core 2. The magnets 1 are arranged in notches 6 provided on the outer periphery of the iron core 2 according to the number of magnetic fields, and the magnetic poles thereof are arranged so that the poles of adjacent magnets are the same. The laminated core 2 is manufactured using a punching die, and is automatically fixed in the die using a polymeric fixing portion 5 as the fixing method. The magnet 1 is fixed to the notch 6 by press-fitting or adhesive. 1/2 of the dimensional difference between the armature 4 and the inner diameter of the stator core 2 is called an air goat and is indicated by a. The stator core 2 is further provided with a notch 7 below the magnet 1.
The dimension h consisting of the bottom and the inner diameter is made as small as possible.

The purpose of providing these two-stage notches 6 and 7 is to simplify the installation position of the magnet 1.
Of course, if the magnet 1 can be easily positioned in the radial direction by another method, the notch 6 may be used instead of the notch 7.

As described above, in the conventional laminated core, the portion h shown in FIG. 1 is made as small as possible in order to increase the efficiency of the magnetic circuit. The reason is as follows. In other words, it is easy to understand if you think about the flow of magnetic flux, but the magnetic flux f emitted from the N pole of magnet 1 is the same as the magnetic flux f emitted from the N pole of adjacent magnet 1'.
While protesting against f′, some of the stator core
Only f ₁ passes through, and the remaining f ₂ crosses the air goat a, passes through the armature 4, and returns to the south pole of the magnet 1.

Here, on the magnetic circuit, f ₁ is an inactive magnetic flux that does not make any movement with respect to the rotation of the motor. Therefore, N
It is desirable that all of the magnetic flux from the poles flows as shown in f ₂ . However, since the magnetic resistance of the iron core is much smaller than that of the air space, the magnetic flux from the N pole tends to become a large reactive magnetic flux due to the presence of the air goat a. In order to solve this problem, conventionally, the air goat a was made as small as possible in processing and assembly to reduce the magnetic resistance of the space, and the h section was similarly made as small as possible in processing. Increases magnetic resistance. Now, the iron core 2 is generally produced using a punching die, but it is generally said that the limit of processing width for narrow parts such as the h section is the thickness of the plate, and the electric motor core is not efficient. Since the lamination of thin plates is good from the point of view of
A plate material with a thickness of mm is used.

Thus, the minimum dimension of the h section that can be processed with a punching die is about 0.3 to 0.5 mm.

On the other hand, as a motor manufacturer, in order to meet the market needs for improving various motor characteristics,
For example, while efforts are being made to make the air goat a as small as technically possible, the same can be said of the h section.

Conventionally, making the h section extremely thin has been achieved by further machining, such as cutting or grinding, the inner diameter of the iron core. Ideally, the h dimension should be zero, but considering the strength or accuracy error after lamination, it should be 0.1~
The limit is 0.15mm.

Furthermore, since this dimensional variation has a great effect on various motor characteristics, it is necessary to strictly control the dimensions. In this way, conventionally, making the h section ultra-thin requires precision machining after laminating the punched core, which complicates production equipment and production management, and this cost cannot be overlooked. It was hot.

The present invention aims to provide a stator core that eliminates these drawbacks, and will be described in detail below. An embodiment of the present invention is shown in FIGS. 3 and 4. FIG. 3 is a plan view of one embodiment, and FIG. 4 is a sectional view thereof. In the present invention, as shown in FIG. 3, part h is separated by some means to form a gap α, and as shown in FIG. 4, this separation is not performed for a certain number of laminates. This holds true.

By cutting off the h portion of most of the laminated plates, the above-mentioned ineffective magnetic flux f ₁ cannot pass through the h portion due to the air gap α, which is much larger than the air gap a, and can therefore be drastically reduced. This is because even if the h part is large, it is sufficient to make α much larger than the air goat a.
It becomes possible to eliminate the need for machining for ultra-fine parts.

Now, in a laminated core that is polymerized and fixed, providing the air gap α according to the number of fields means that the stator core is
, . . . each becomes an individual piece, making it difficult to obtain concentricity after assembly. For this reason, it is possible to cut the magnets from the inner surface after gluing them together, but for motors that meet market needs for smaller sizes, machining or laser processing can be used to cut the gap α from the inner surface. This is technically extremely difficult and has low productivity.

For this reason, before bonding, the gap α is processed by some means from the outer periphery, and at this time, the gap α is processed while leaving an arbitrary number of laminates.

For example, as shown in Figure 4, each laminate is _C1 ...
...C _k ...C _n ...C _o , C ₁ and C _k , C _n ,
C ₂ ~ _{C k-1} , C _k+1 ~ _{C n-1} , C _n leaving 4 cards of C _o
A gap α is formed in the laminate between ₊₁ and C _{o -1} . Of course, it is most efficient to process the voids α for all of C ₁ to _Co , but there are problems as described above. Normally, the number of stacked sheets is several dozen, and even if a few sheets are left behind, the efficiency does not decrease much. However, it is better to keep the number of sheets that do not form the void α as small as possible, and this will vary depending on the formation, size, etc., but it will be determined by the required strength after lamination. As can be understood from the magnetic circuit, no matter how wide the air gap α is, it will have no effect if it exceeds a certain width. On the other hand, if the dimensions exceed a certain level, the tolerance range is wide, that is, a rough dimensional tolerance is sufficient. Needless to say, the present invention applies not only to the servo motor as an embodiment but also to corner motors, capacitor motors, etc.

As described above, the present invention can improve the efficiency of a magnetic circuit without making processing accuracy a problem, and its industrial value is extremely high and effective.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional stator core for a servo motor, FIG. 2 is a sectional view of the same, FIG. 3 is a plan view of a stator core for a servo motor according to an embodiment of the present invention, and FIG. 4 is a sectional view of the same. It is. 1, 1'...Magnet, 2...Iron core, 5...Polymerized fixed part, α...Gap.

Claims (1)

[Claims] 1. A laminated core formed by polymerizing and fixing a plurality of thin plates, which is characterized in that the remaining laminated cores except for a certain number of sheets between the laminated layers are laminated and polymerized with a gap separating the constituent magnetic poles. laminated iron core for electric motors.