JPH0588192U - Linear motor iron core - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the weight of the iron core of a linear motor. [Structure] The cross-sectional areas of both ends of the iron core are made smaller than the cross-sectional area of the central part. As a result, the weight of the iron core at both ends becomes small, and the weight of the iron core is reduced. Since the magnetic flux density at both ends of the iron core is small and the excess iron core is removed, the loss hardly increases due to the small cross-sectional area.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a lightweight linear motor iron core.

[0002]

[Prior Art]

 In the linear motor drive method, the method in which the primary side is provided on the moving body and the secondary side is provided on the fixed side (moving path, rails, etc.) is called the terrestrial secondary method. On the other hand, a system in which the primary side is arranged on the fixed side and the secondary side is provided on the moving body is called the ground primary system. Fig. 4 shows an iron core conventionally used on the primary side of these systems. In FIG. 4, the iron core 4 is formed by laminating substantially comb-shaped silicon steel thin plates 40a to 40n, whereby a yoke 44 as a magnetic flux path, tooth portions 42a to 42n protruding from the yoke 44, and a space between the tooth portions. Slots 41a to 41n are formed. Further, primary windings (not shown) are embedded in the slots 41a to 41n of the iron core 4. The iron core 4 is provided so that the tooth portions 42a to 42n face a secondary side (not shown) of the linear motor with a predetermined gap.

[0003]

[Problems to be solved by the device]

 By the way, there are various fields of application of linear motors. One example is a system in which a linear motor car is used to convey goods by constructing a tunnel network for conveying goods underground in the city. If the existing ground equipment is used as a transportation base, it is necessary to enable physical exchange between the underground transportation network and the ground equipment. It is necessary to ascend and descend steeply inclined tracks.

However, in the conventional ground secondary type linear motor carrier, since a heavy iron core is mounted on the moving body, it is not suitable for going up and down a steeply inclined track. .. On the other hand, in the linear motor transport system of the primary system on the ground, when the rapid acceleration / deceleration is required or the vertical transport is required, it is necessary to arrange a large number of primary sides. There was a problem that it became heavy. The present invention has been made in view of the above circumstances, and an object thereof is to provide a lightweight linear motor core.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is an iron core constituting a primary side of a linear motor, characterized in that the cross-sectional area of both ends in the magnetic flux traveling direction is smaller than the cross-sectional area of the central part. I am trying.

[0006]

[Action]

 In the present invention, the cross-sectional area of both ends in the direction of magnetic flux travel is made smaller than the cross-sectional area of the central part, so the weight of the portion corresponding to the difference between the two is reduced. On the other hand, since the magnetic flux density at both ends of the iron core is small, the increase in loss due to the small cross-sectional area is extremely small.

[0007]

【Example】

 First, the principle of the present invention will be described with reference to FIGS. In order to simply reduce the weight of the iron core 4 shown in FIG. 4, it is conceivable to employ a means of reducing the width of the iron core 4 by reducing the number of the silicon steel thin plates 40a to 40n. However, if the width of the iron core 4 is simply made small, the magnetic flux density of the iron core 4 becomes large and the iron core 4 becomes saturated, resulting in a problem that reactive current, eddy current loss and hysteresis loss increase.

On the other hand, the magnetic flux density of the iron core 4 is not uniform in each part, and in the case of a general winding method of full-pitch winding in which the number of slots for each pole and each phase is “1” in three phases, a slot at the end is used. With the upper coil, only the upper coil is inserted, and the magnetic flux density at the end of the iron core 4 is smaller than that of the upper coil that is inserted over the upper and lower two phases. This state (at rest) is shown in FIG. Therefore, it is considered that even if the cross-sectional area of the iron core 4 is small at the end, the loss hardly increases, and it is possible to reduce the weight while suppressing the increase of the loss. The above is the principle of the present invention. Hereinafter, various examples will be described.

A. First Embodiment First, a first embodiment of the present invention will be described with reference to FIG. In the figure, an iron core 1 is composed of a middle shaft core 1a formed by laminating a plurality of long silicon steel thin plates, and a silicon steel provided on both sides of the middle shaft core 1a and shorter than the middle shaft core 1a by about one slot pitch. Inner cores 1b, 1b made of thin plates, and silicon steel thin plates provided on both sides of the inner cores 1b, 1b, which are shorter than the middle cores 1b, 1b by about 1 slot pitch. It is composed of the side iron cores 1c and 1c which are formed.

As a result, the cross-sectional area of the central portion of the iron core 1 becomes large and the cross-sectional area gradually decreases toward both ends, so that the weight near both ends is reduced and the weight of the iron core as a whole is reduced. Be reduced.

B. Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. In the figure, the iron core 2 is composed of a molded product of iron powder and resin or a sintered alloy, and is widely formed in the central portion 2a, and in the vicinity of both end portions 2b, 2b, it is tapered toward the both end portions. The width is narrow. As a result, the weight near both ends 2b, 2b is reduced.

C. Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. In the figure, the iron core 3 is constructed by laminating silicon steel thin plates 30a to 30n, and the bottoms are cut out near both ends of each of the silicon steel thin plates 30a to 30n to form cutouts 3a and 3b. As a result, the weight of the iron core 3 near both ends is reduced. This can be realized by making the slots 31a to 31f formed near both ends shallower than the slots 31g to 31j in the central portion.

[0013]

[Effect of the device]

 As explained above, according to the iron core of the linear motor of the present invention, the magnetic flux density is small, the cross-sectional area of both ends in the magnetic flux traveling direction is made small, and the excess iron core is removed so that the loss is hardly increased. It is possible to reduce the weight.

[Brief description of drawings]

FIG. 1 is a perspective view of an iron core according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an iron core according to a second embodiment of the present invention.

FIG. 3 is a perspective view of an iron core according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a conventional iron core.

FIG. 5 is a diagram showing a magnetic flux density characteristic of a void portion (when stationary).

[Explanation of symbols]

 1 iron core 2 iron core 3 iron core

Claims (1)

[Scope of utility model registration request] 1. An iron core constituting a primary side of a linear motor, characterized in that a cross-sectional area of both end portions in a magnetic flux traveling direction is smaller than a cross-sectional area of a central portion.