JPS6216032A - Stator core structure - Google Patents

Abstract

PURPOSE:To prevent the local heating of a joint between stator cores by inserting a member having proper compressibility between the joint between the cores. CONSTITUTION:Fiber in which glass fiber and polyamide fiber are mixed is used as a sheet employed, and the mixing ratio of glass fiber and polyamide fiber is changed, thus adjusting the compressibility of the sheet. When the sheet having compressibility of approximately 0.3/1.0 30% in an average is inserted to an air gap of 0.8.-1.0mm between cores in order to absorb a laminating stepped section of d1(0.2-0.3)mm of thin steel plates, the sheet is fit into the air gap between the cores, and assembly through which the cores are not damaged is enabled. It is desirable that the mixing ratio of glass fiber and polyamide fiber is 1:1 as the sheet. When the sheet is inserted to a joint between the stator core 1 and the stator core by 1mm, the sheet bites to one side by 0.15mm and bites to both sides by 0.3mm because of approximately 30% compressibility, but these values are half an asbestos sheet, and the quantity of biting and the rates of crushing of members are also made smaller than conventional structure even when starting and stoppage are repeated under the state, thus preventing the local heating of the joint section between the stator cores.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a stator core structure, and particularly to a structure suitable for preventing local overheating of a stator core joint.

[Background of the invention]

FIGS. 1 to 3 show an example of a conventional stator split structure and an example of an insertion member inserted into the split portion. Generally, the stator of an alternator is cylindrical with a large outer diameter.

Since the outer diameter is 10 to 15 m, due to problems such as transportation to the installation site, it is normal to have a structure that is divided into multiple pieces as shown in Figure 1. Naturally, the child core 1 is also divided into the same number of stator frames. The stator core to be divided is made by laminating segment-shaped thin steel plates 3 forming a plurality of slots 2, and
It consists of a thin rust plate pressing plate 4 that presses the thin steel plates in the direction of lamination, and a tightening bolt 5 that tightens the thin steel plates in the direction of stacking. A gap of 0.8 rrn to 1 stroke is provided at the joint 6 between the divided stator cores and the adjacent divided stator cores to facilitate assembly work and to absorb thermal elongation of the stator cores. As the member inserted into the gap of this joint, an asbestos sheet 7 is used as a cushioning material, and the asbestos sheet is rectangular and is usually inserted over the entire surface of the stator core joint. If you look closely at the joint of the stator core, you will notice that because the thin steel plates are laminated, the joint surface is not flat as shown in Figure 3, but has a step of about 0.3mm from 0.2mo+. The occurrence of this level difference is unavoidable in the process of laminating thin steel plates. The compression rate of the asbestos sheet inserted between the joints is as high as approximately 60%, and if the asbestos sheet inserted between the joints is 1 rm as shown in Figure 3, the compression rate is 60%, so one side is 0.6 m on both sides of 8 where d0 bites 0.3on
When the asbestos sheet is repeatedly operated and stopped in this condition, the asbestos sheet in the part that has been dug in becomes uneven due to the thermal expansion and contraction in the circumferential direction of the stator core and the thermal expansion and contraction in the axial direction. A large frictional force and tensile force are applied.

In particular, this frictional force and tensile force are large for models that frequently start and stop, or models that are long in the axial direction. Due to this frictional force and tensile force, the asbestos sheet inserted into the stepped portion is finely pulverized, and a phenomenon occurs in which the stator cores at the joint portion come into contact with each other. Frictional forces caused by thermal expansion and contraction in the circumferential direction of the stator core also caused the insulating coating applied to the core to tear, resulting in short circuits and local overheating.

Regarding this kind of stator core structure, for example, there is Japanese Utility Model Publication No. 59-398166 [Object of the Invention] The object of the present invention is to The object of the present invention is to provide a stator core in which the core joints are not locally overheated by inserting a member having an appropriate compression ratio.

[Summary of the invention]

As a result of various investigations into the causes of local overheating that occurs at the joints of stator cores in split structures, the following was found. That is, the asbestos sheet inserted between the stator cores has a high compression ratio, low tensile strength, thin fiber thickness, and short fiber length. For this reason, the inserted members were crushed by the frictional force generated by the thermal expansion and contraction of the stator core, resulting in local overheating.

As a result of testing the relationship between compression ratio and local overheating, if a member with a high compression ratio is inserted, as described above.

If the stator core is easily crushed due to expansion or contraction, or if a material with a low compressibility, such as a wire or ceramic material, is inserted, heat may be generated at the core joints if the stator core expands. Since there is no stretch relief, the core is placed above the laminated part.
Or, it will bend downward and the upper and lower cores will come into contact. It was confirmed that local overheating had occurred due to repeated contact between the upper and lower cores due to the expansion and contraction of the core.

The relationship between compression ratio and local overheating is expressed graphically as shown in Figure 4, and it is best to insert a member between the joint between the stator core and the stator core with a compression ratio of 30% to 40%, as this will result in less local overheating. It turned out to be.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 3, and FIG. 4 shows a graph showing the relationship between the compressibility of the insertion member and local overheating.

The sheet used in the present invention is a mixture of glass fiber and polyamide fiber, and the compression ratio of the sheet can be adjusted by changing the mixing ratio of glass fiber and polyamide fiber. In the present invention, the air gap d2 between the iron cores is 0.8 to 1.0 m, and if the average is 1.0 to absorb the laminated step d of the thin steel plate, which is 0.2 to 0.3 mm, the air gap between the iron cores is 0.8 to 1.0 m. can be assembled without damaging the iron core. The sheet preferably has a mixing ratio of glass fibers and polyamide fibers of approximately 1:1.

When this glass fiber mixed sheet is inserted into the joint between stator core 1 and stator core, the compression ratio is approximately 30%.
Therefore, it digs in by 0.15 m on one side, which is 0.15 m on both sides.
3. The amount of penetration is about half that of asbestos sheets, and even if you start and stop it repeatedly in this state, the amount of penetration is less compared to conventional asbestos sheets, and even when you compare fibers. Since glass fiber is thicker and longer than asbestos, the insertion member inserted into the joint is less likely to cause fine pulverization, making it possible to prevent local overheating of the joint of the stator core.

〔Effect of the invention〕

According to the present invention, since the insertion member inserted between the joints of the stator core is less likely to be crushed due to aging, local overheating of the joints of the stator core can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a front view of a stator core with a seam according to the present invention, Fig. 2 is a view from the ■-■ arrow in Fig. 1, Fig. 3 is a conventional compressed insert member, and Fig. 4 is a diagram showing the compression ratio. It is a figure showing the relationship of local overheating.

Claims (1)

[Claims] 1. Segment-shaped thin steel plates forming a plurality of slots extending toward the center on the inner diameter side are laminated, and a presser plate is configured to press the thin steel plates in the stacking direction. In a stator core structure in which the stator core is manufactured by dividing the stator core into an appropriate number of pieces around the circumference and combining them, when the stator cores are assembled, compression is applied between the joints between the stator cores. A stator core structure characterized by inserting a sheet containing a mixture of glass fibers having a ratio of 30% to 40%.