JPS59149751A - Rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent the resonance of a circular ring and to reduce the noise by forming a slit which extends radially of a stator core and is longer than the radial minimum thickness of the core at least one position of the core along the circumferential direction of the core. CONSTITUTION:A slit 31 is formed at one position of a stator core 30 in the circumferential direction. This slit 31 radially extends, opens at one end at the outer peripheral surface of the core 30, and opens at the other end at the inner peripheral surface of the core 30. The core 30 is divided in the course in the circular shape of the circumferential direction with the slit 31 in a discontinuous manner. Accordingly, the core 30 is reduced in diameter, introduced into the housing 5. When the reduction in the diameter is released in the housing 5, the core 30 is expanded by the elastic recoiling force, and the outer surface is elastically secured to the inner surface of the housing 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to rotating electric machines such as generators and electric motors, and particularly to a stator core thereof.

As a type of rotating electric machine, a vehicle alternating current electric machine shown in FIG. 1 will be explained as a representative example. When a field rotor 1 driven by an engine rotates, a rotating magnetic field is generated in a laminated stator core 2. Stator winding 3 wound around this stator core 2
A three-phase electromotive force is generated, and power is supplied to an external load through a three-phase bridge (not shown). In this case, the magnetic force applied from the field rotor 1 to the stator core 2 and the load current flowing through the stator winding 3 cause the stator core 2 to
A diamagnetic force is generated. These two magnetic forces generate an electromagnetic repulsion force in the gap 4 between the rotor 1 and the stator 2, and this repulsion force forms a rotational traveling wave and therefore pulsates. This pulsating repulsive force always applies an excitation force to the inner wall of the stator core 2, and when the excitation force matches the natural frequency of the stator core 2, the second
This causes ring resonance as shown in the figure, causing noise.

It is thought that the above resonance can be improved and noise can be prevented by tightly fitting the outer surface of the stator core 2 and the inner surface of the housing 5 with a large amount of tightening. This increases stress and requires greater rigidity for the housing 5, leading to problems such as increased weight due to thicker walls.

Conversely, if the tightness between the stator core 2 and the housing 5 is reduced, the difference in thermal expansion between the housing 5, which is usually made of non-magnetic aluminum material, and the stator core 2, which is made of a ferrous material, increases. When resonance occurs in the stator core 2, the stator core 2
It begins to hit and generate extremely loud noise.

The present invention was developed based on the above circumstances, and its purpose is to reduce the occurrence of resonance in the stator core itself to prevent noise, and to prevent dimensional variations in the stator core and housing due to molding. It is an object of the present invention to provide a rotating electrical machine that can absorb this variation even if it exists, allows the stator core to be easily attached to the housing, and improves assembly efficiency.

That is, the present invention provides a stator core by forming a slit in the stator core at least at one position along the circumferential direction, extending in the radial direction of the core, and having a length longer than the minimum thickness of the core in the radial direction. The stator core is divided along the circumferential direction to prevent annular resonance and reduce noise, and the slits are made to open the outer peripheral surface of the stator core to reduce the outer diameter of the core. The stator core is elastically expandable and contractable, and its elastic diameter expansion force causes the stator core to bounce against the inner surface of the housing to maintain a large tightening margin, prevent the housing from hitting, and absorb dimensional variations through the elastic expansion and contraction action. This is how it was done.

An embodiment of the present invention will be described below based on FIG.

FIG. 3 is a sectional view according to the present invention taken along the line ■-■ in FIG. 1, in which a slit 31 is formed in the stator core 30 at one location along the circumferential direction. This slit 31 extends in the radial direction, and one end of the slit 31 is connected to the stator core 3.
0 and the other end is open to the inner peripheral surface of the stator core 30.

Since the stator core 30 has the slits 31, the annular shape in the circumferential direction is divided in the middle and becomes discontinuous. When the stator core 30 is in a free state where it is not inserted into the housing 5, the outer diameter of the core 30 is slightly larger than the inner diameter of the housing 5, as shown by the imaginary line, and the stator core 30 has a slit 31. The outer diameter can be elastically reduced. Therefore, when inserting the stator core 30 into the housing 5, the stator core 30 is reduced in diameter, introduced into the housing 5, and released within the housing 5. The diameter expands due to the elastic return force, and the outer surface hits the inner surface of the nozzle 6. For this reason, the width of the slit 31 is smaller in the free state t1 (about 1.5 mm) than in the state t2 fitted inside the pufferfish 5 (about 1.5 mm).

According to the above configuration, the stator core 30 is divided by the slits 31 and is discontinuous in the circumferential direction, so that a pulsating repulsive force is generated by the electromagnetic repulsive force described above, and an excitation force is generated. Even if it is transmitted, it will cause ring resonance and become separated. The resonance is reduced because the resonance is divided. Therefore, the noise level 5- is reduced.

Further, since the stator core 30 is elastically attached to the inner surface of the housing 5, it is supported with a suitable interference margin. Therefore, the iron core 30 will not hit the housing 5.

Furthermore, even if there are dimensional variations in the inner diameter of the housing 5 or the outer diameter of the stator core 30 due to machining, the stator core 30 can elastically expand or contract its outer diameter, so the dimensional variations can be absorbed by the core 30, and assembly can also be done easily. Furthermore,
Even if a difference in thermal expansion occurs between the stator core 30 and the housing 5 due to temperature increase in the usage environment or during use, the difference can be absorbed by the slits 31.

Although it may be thought that dividing the annular shape by forming slits 31 in the stator core 30 will have negative effects on the magnetic circuit configuration, theoretically, the negative effects are as follows: It is explained that there is no In other words, if we consider two arbitrary points in the circumferential direction of the stator core 300 and assume that there is a magnetic potential difference between them, the magnetic flux that will flow between these two points will be There are two passages along the circumferential direction of the iron core 30, one in the clockwise direction and one in the counterclockwise direction. By dividing by the slit 31, the passage of magnetic flux in one direction is completely lost, but the magnetic flux in the other direction may become saturated to some extent and become difficult to flow, but the magnetic flux can still flow. Furthermore, in the case of automotive alternators, there are generally 10 to 14 poles, so the magnetic flux loss due to saturation is reduced to the value divided by the number of poles in terms of overall output, so it is effectively Does not cause any problems. By the way, 12V75A class 1
In the two-pole vehicle alternator, when t is used in this embodiment,
, = 1.0 When comparing the output of the one with slit 31 and the conventional one without the slit, it was confirmed that the output was almost the same, with the difference being within the error range of the measuring device. .

4 to 7 respectively show other embodiments of the present invention, and in the example of FIG. 4, a key 40 is attached to the housing 5 to prevent rotation of the stator core 300 in the circumferential direction. This is what I did. A minute gap 6 is ensured between this key 40 and the side surface of the slit 31.

In the example shown in FIG. 5, the slit 31 is filled with an adhesive 50 and the adhesive 50 is adhered to the housing 5. The adhesive 5 is preferably an elastic adhesive.

FIG. 6 shows an example in which a so-called cut-out slit is used, in which one end of the slit 60 is a closed end. In this case, the other end of the slit 60 is open on the outer peripheral surface side of the stator core 30, so that the outer diameter can be elastically expanded or contracted. Furthermore, the radial length of the slit 60 is the same as that of the stator core 60.
The wall thickness t along the radial direction is also large, thereby realizing the above-mentioned dividing action and elastic deformation action. Furthermore, the seventh
The figure shows the outer circumferential surface of the stator core 70, and by arranging the slits η along the axis 0-0 direction in a staggered manner in the circumferential direction, the same effect as in the embodiment shown in FIG. 3 can be obtained. It was designed to occur.

The omitted present invention can be implemented not only for alternating current but also for direct current, and can be implemented not only for generators but also for electric motors.

As described above, according to the present invention, slits are formed in the stator core to prevent ring resonance, so noise is reduced.
In addition, since the stator core is configured to elastically expand and contract its outer diameter using the slits mentioned above, the stator core can be made to snap onto the housing, preventing knocking, and absorbing dimensional variations to improve processing accuracy. It has the advantage that there is no need to lift it up and it is easy to assemble.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view for explaining the conventional technology, Fig. 2 is an explanatory view of its annular resonance, and Fig. 3 is a cross-sectional view of the present invention shown along the line ■-■ in Fig. 1. 4 to 7 are explanatory diagrams showing other embodiments of the present invention, respectively. 1...Rotor, 5...Housing, 30.70...
・Stator core, 31,6.0.71...S') ツ)
a9- Figure 4 Figure 7

Claims (1)

[Claims] A slit extending in the radial direction of the core and longer than the minimum thickness in the radial direction of the core is formed at at least one location along the circumferential direction of the stator core, and the slit is formed at least on the outer peripheral surface side of the stator core. A rotating electric machine characterized in that the outer diameter of the core can be elastically expanded or contracted by opening the stator core, and the stator core is made to snap onto the inner surface of the housing by the elastic diameter expansion force.