JPS6112468B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a stator core by spirally winding a strip core.

Generally, the stator, which has been wound spirally, is finally shaped and subjected to the subsequent winding process and machining process of the joint part, but machining errors during punching of the strip core and material itself Due to variations in the plate thickness, conventional shaping methods do not provide sufficient precision in the diameter of the inner surface of the stator, which is made up of teeth that face the rotor. The current situation is that Furthermore, when wound spirally, the rectangular cross section deforms into a trapezoid, making the laminated structure unstable and making effective shaping difficult.

This invention solves these drawbacks and provides a stator core that is economical by making the laminated structure stable, making shaping more effective, and increasing the accuracy of the inner diameter and eliminating the need for post-processing. This is an excellent manufacturing method that allows for

The present invention will be explained below based on the drawings. That is, Figures 1 and 2 show the core wound spirally before final shaping. In the figures, 100 is the core, 1 is the opening, 2 is a continuous part of the core, and 3 is arranged at equal intervals. A convex portion (hereinafter referred to as a tooth portion) 4 is an inner surface of the stator core facing a rotor (not shown), 5 is an outer surface thereof, 6 is a winding start end portion of the band-shaped core, and 7 is a winding end portion thereof. By the way, when manufacturing a stator core having the above-mentioned configuration, the conventional shaping method uses a compression process only to make the step formed by the starting end 6 and the ending end 7 parallel, since variations in processing of the inner surface 4 are unavoidable. was prepared. FIG. 3 shows a state in which the material has been compressed and shaped by the conventional method, and 101 is a first flat plate placed, for example, on a fixed stand of a hydraulic press, and 102 is a second flat plate placed on a plunger. The stator 100 clamped by both flat plates is given a curvature on the line connecting the starting end 6 and the ending end 7, and the starting end side plane 6a and the ending end side plane 6b become parallel to each other, forming a completed stator core. . However, as can be easily imagined from the figure, the error in the diameter of the inner surface 4 during winding remains as it is, and it is inevitable that the cylinder will collapse. Therefore, in the conventional method, as shown in FIG. 4, an additional machining step is required to supplement this by means such as a lathe. That is, in FIG. 4, 8 indicates a portion removed by a lathe or the like, and the stator core is now completed.

Next, a method of the present invention that can overcome the above-mentioned drawbacks will be described.

First, in FIG. 5, 101 is a first flat plate installed on a fixed base such as a hydraulic press, and 102
is a second flat plate 10 installed on a movable part of a hydraulic press provided opposite to the first flat plate 101;
3 is a cylindrical tool such as a punch having an outer diameter larger than the diameter of the inner surface 4 of the stator core before shaping, and 103a is provided at the tip of the punch to facilitate insertion of the punch into the inner surface 4 of the core. slope section 10
A hole 1a is provided in the first flat plate 101 of the punch and has an appropriate clearance with respect to the outer diameter of the punch 103. Here, it is assumed that the second flat plate 102 and the punch 103 are installed in a press that can operate independently under different hydraulic controls. Next, the operation according to this method will be explained. FIG. 6 shows the first step according to the present invention, in which no pressure is applied to the first and second flat plates 101, 102, or the inner diameter 4 is expanded by the punch 103 with a relatively small force. The starting end surface 6a and the ending end surface 7a of the iron core are set so as not to be a major hindrance when moving in the radial direction when the iron core is moved. In this state, press fit the punch 103 to expand the inner surface 4,
Next, a predetermined pressure is applied between both flat plates 101 and 102 in order to eliminate the level difference between the starting end portion 6 and the ending end portion 7.

FIG. 7 shows the second step, in which the punch 103 is removed when the level difference between the end portions 6 and 7 becomes worse, and then the pressure on the second flat plate 102 is released.

The shaping process is completed above, and the reason why the variation in the inner diameter during winding can be substantially eliminated by press-fitting the punch 103 will be explained. In Fig. 8, 104 is the punch 10
The internal pressure P ₁ applied by the punch during insertion of 3,
105 is a tensile stress σt given by the internal pressure 104.

As is clear from the figure, it can be seen that the theory of thick-walled cylinders in mechanics is practically applied. Mechanics teaches that when the above-mentioned tensile stress σt exceeds the elastic limit, the continuous portion 2 undergoes plastic deformation, and when P ₁ is removed, it recovers from that point by substantially the amount of elastic deformation. In other words, in Fig. 9, the horizontal axis represents the deformation dimension,
When the tensile force is plotted on the vertical axis, it shows that the method of recovery within the elastic limit is almost constant regardless of the magnitude of plastic deformation. In the figure, 106 indicates a deformation state when the plastic deformation is relatively small, that is, the outer diameter of the punch 103 is slightly larger than the inner diameter of the stator 100 before shaping, and 107 indicates a state when the plastic deformation is large, that is, the state of the stator 100. This shows the state when the inner diameter becomes smaller. When the punch 103 is removed, they return to 106a and 107a, respectively, but the return amounts at this time are 106b and 107b, respectively, and it can be assumed that 106b and 107b are substantially equal. Since the outer diameter of the punch 103 is fixed, it can be seen that even if there is a difference in the amount of plastic deformation due to variation in the inner diameter of the stator 100, the variation in the inner diameter after shaping is extremely small. Furthermore, punch 103
Needless to say, since the inner diameter of the stator can be prevented from collapsing due to the insertion and compression, there is no need for additional machining as shown in FIG.

FIG. 10 shows an embodiment in which a portion with low physical strength is intentionally provided in the continuous portion 2 of the stator 100 to improve the lamination condition through plastic deformation.

In the figure, 2a is a recess provided to reduce the physical strength of the continuous portion, and 2b is a portion where the original method is maintained. That is, the A-A cross section before shaping and the B-
The cross section B has the shape shown in FIG. 11, and it is inevitable that there is a portion that is bent intensively at the recess 2a and becomes larger than the thickness before winding. Therefore, when the punch 103 is inserted and the internal pressure P ₁ 104 is applied in the above-described manner, a tensile stress σt 105 appears in the continuous portion 2. Plastic deformation mainly appears only in cross section AA, and deformation in cross section B-B is relatively small. As a result, only the cross section A-A mainly shrinks, and the cross section after shaping becomes the state shown in Figure 12, where the part where the material plate thickness has increased due to bending approaches the original material plate thickness, and mutual interference occurs during lamination. This allows for close contact at the cross-section B-B portion.

FIG. 13 shows an embodiment in which a key is provided on the punch 103 to prevent the teeth 3 of the stator 100 from falling in the radial direction during shaping, and 103a is arranged on the surface of the punch 103. It has a width approximately equal to the opening portion 1 formed between the teeth of the provided key.

In this embodiment, by press-fitting the key 103a into the opening 1 at the same time when inserting in the above-described manner, it is possible to prevent the tooth 3 from falling in the radial direction when it is compressed by both the flat plates 101 and 102.

As described above, according to the present invention, after the outer periphery of the stator core is held in a free state so that the wound stator core can be deformed outwardly, the wound stator core has a diameter larger than the inner diameter. By press-fitting a cylindrical tool having If the outer periphery of the stator is freed and the inner surface is expanded, the continuous part will be plastically deformed, so when the cylindrical tool is removed, the amount of elastic deformation will be approximately the same regardless of the amount of plastic deformation, and the stator The inner diameter of the core is determined by the outer diameter of the cylindrical tool, which improves the accuracy of the inner diameter of the stator core, eliminates lathe machining of the inner diameter, and significantly improves productivity. has.

In addition, although it is possible to improve the winding workability of the stator core in the case of a concave part provided in a continuous part, there is a risk that the thickness of the plate becomes extremely large in the concave part. By press-fitting a cylindrical tool into the inner surface of the child core, plastic deformation accompanied by tensile stress will be concentrated in the recess, and the thick part of the recess where the plate thickness has become extremely large during the winding operation will be concentrated in the recess. It also has the effect of reducing the amount of heat and allowing the laminated iron cores to be brought into close contact with each other.

[Brief explanation of the drawing]

Figure 1 is a top perspective view showing the stator core before shaping, Figure 2 is a side view showing the step between the winding start and end of the stator before shaping, and Figure 3 is a side view showing the conventional shaping method. , FIG. 4 is a side cross-sectional view showing the part that requires additional work to correct the variation and collapse of the inner diameter of the iron core obtained by the conventional shaping method, and FIG. Figures 6 and 7 are side sectional views showing the steps of the shaping method using the equipment shown in Figure 5, and Figure 8 shows the mechanical effects that appear on the iron core when this equipment is used. Figure 9 is a diagram showing the relationship between plastic deformation and elastic deformation, Figure 10 is a diagram showing the core shape and mechanical relationship for concentrating plastic deformation locally, and Figure 11 is a diagram showing the mechanical relationship. FIG. 10 is a diagram showing the relative relationship of the cross sections of the iron core before shaping, FIG. 12 is a diagram showing the relative relationship of the cross sections of the iron core after shaping shown in FIG. 10, and FIG. 13 is another embodiment of the present invention. FIG. In the figure, 100 is a stator core, 3 is a tooth portion, and 4 is a stator core.
is the inner surface, 103 is the punch, 2 is the external continuous part, 2
a is a recessed portion, and 103a is a key arranged on the outer surface of the punch. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A stator core for manufacturing a stator core that is constructed by spirally winding a band-shaped core and has a cylindrical inner surface that faces the rotor and is made up of a plurality of teeth connected by a continuous section, After holding the stator core with the outer periphery of the stator core in a free state so that the wound stator core can be deformed outward, a cylindrical tool having a diameter larger than the inner diameter is inserted into the stator core. The tensile stress acting on the continuous portion is made to exceed the elastic limit by press-fitting into the inner surface and pressing the tooth portion, and then, after compressing the stator core in the winding direction, the cylindrical tool is A method of manufacturing a stator core, in which a continuous portion of the stator core is permanently deformed by being removed so as to have a predetermined inner diameter related to an outer diameter of the cylindrical tool. 2. The stator core manufacturing method according to claim 1, characterized in that a concave portion is provided in the continuous portion to intensively apply permanent strain to the stator core so as to have a predetermined inner diameter. 3. The stator core manufacturing method according to claim 1 or 2, wherein the cylindrical tool is a punch. 4. The cylindrical tool is composed of a punch having a plurality of keys on its outer surface, and the teeth are aligned by inserting each of the keys between the teeth. A method for manufacturing a stator core according to claim 1 or 2.