JPH0491649A - Cage-type induction motor - Google Patents

Abstract

PURPOSE:To enable brazing or adhesion property to be improved and at the same time concentration of stress at a maximum stress point of a rotor bar to be relaxed for preventing an accident where the rotor bar is broken from occurring by forming a filling part on a short-circuiting ring side in a lower contact part of the rotor bar and a rotor core side end face of the short-circuiting ring and by connecting this filling part and the rotor bar with silver brazing or welding. CONSTITUTION:A corner angular part is constituted at a corner of both side surfaces of a rotor bar 3 and a filling part B by forming the filling part B at a side of a short-circuiting ring 4 over and entire periphery on a rear surface of the rotor bar 3 and the short-circuiting ring 4, namely at the end face on the side of a rotor core 2 and a contact part in the lower part of a point A and this filling part B and the rotor bar 3 are connected by silver brazing or welding, thus enabling a fillet part of the rotor bar 3 to be silver-brazed or welded to be formed at both sides and also on a lower surface with the filling part B for increasing reliability of silver brazing or welding. Also, concentration of stress due to bending can be relaxed by forming the filling part B in a lower part of a rear-surface side of the short-circuiting ring 4 with the maximum stress point A. At this point, no accidents occur where the rotor bar 3 is broken.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention relates to a squirrel cage induction motor, and in particular, to a squirrel cage induction motor, and particularly to a squirrel cage rotor (hereinafter simply referred to as a rotor) that is short-circuited to a rotor bar. This invention relates to a squirrel cage induction motor with an improved connection structure with a ring.

(Prior Art) FIG. 3 is a longitudinal sectional view showing an example of the configuration of a conventional squirrel cage induction motor of this type.

In Fig. 3, a cylindrical rotor core 2 is formed by press-fitting a laminated body of a plurality of ring-shaped silicon steel plates into the rotating shaft 1, and the outer periphery of the rotor core 2 has a bag-shaped cross section at equal pitches in the axial direction. A plurality of slots are formed, and rotor bars 3 having the same shape cross section as the slot are inserted into these slots, and both ends of these rotor bars 3 are connected to the rotor bar 3 respectively.
The rotor is constructed by connecting by silver brazing or welding with a copper short-circuit ring 4 having a slot with the same shape and cross section formed on the outer periphery, and further pressing the rotor core 2 from both sides with core holders 5 and 6. There is.

The rotor bar 3 has a trapezoidal or rectangular cross-sectional shape, but in the case of a main motor for a railway vehicle that rotates at high speed, for example, the cross-sectional shape is rectangular, and the rotor bar 3 has a trapezoidal shape or a rectangular shape. A slot is provided so that the rotor bar 3 protruding from the rotor core 2 can be inserted and connected, and the contact portion is connected by silver brazing or welding. In addition, in order to suppress the thermal stress and centrifugal force of the rotor bar 3 and short-circuit ring 4, the high-speed rotor is equipped with a retaining ring made of non-magnetic steel on the outer periphery of the short-circuit ring 4, as shown in FIG. 7 is shrink-fitted. The expansion coefficient of this retaining ring 7 is almost the same as that of the short circuit ring 4, but in order to prevent it from coming off due to vibration,
Usually, as shown in FIG. 4, a convex portion 8 is formed on the outer periphery of the shorting ring 4 by machining together with the fitting surface of the retaining ring 7.

Note that the stator core 1 is provided on the inner surface of the casing 9 of the motor.
0 is fixedly attached, and furthermore, a stator coil 11 is wound around this stator core 10.

Further, FIG. 5 is a diagram showing a YY cross section in FIG. 4.

However, a squirrel-cage blade conductive motor equipped with such a rotor has the following problems.

That is, the rotor bar 3 and the short-circuit ring 4 are silver-brazed or welded before the retaining ring 7 is shrink-fitted, but the silver-brazed or welded surface is complicated with the inner and lower surfaces of the rotor bar 3. Because there are multiple pieces at equal pitches, special techniques are required for silver brazing or welding, and depending on the failure of silver brazing or welding, rotor bar 3 and short circuit ring 4 may Since the electrical contact with the rotor bar 3 is insufficient, the rotor bar 3 vibrates due to electric shock vibration and rotational vibration, which promotes breakage of the rotor bar 3. Furthermore, the stress distribution due to the thermal stress and centrifugal force stress of the rotor bar 3 is as follows.
The point A shown in the lower part of the back side of the short circuit ring 4 shown in FIG.

(Problems to be Solved by the Invention) As described above, in a conventional squirrel-cage blade conductive motor equipped with a rotor, reliability and brazing or weldability of silver brazing or welding between the rotor bar and the short-circuit ring are There was a problem that not only was the rotor bar low, but also rotor bar breakage accidents occurred.

The purpose of the present invention is to improve the reliability and braze or weldability of silver brazing or welding between the rotor bar and the short-circuit ring, and to alleviate the stress concentration at the maximum stress point of the rotor bar. It is an object of the present invention to provide a squirrel-cage blade conductive motor equipped with a rotor capable of preventing bar breakage accidents.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a cylindrical structure formed by press-fitting a laminated body of a plurality of ring-shaped silicon steel plates onto a rotating shaft. A plurality of slots with a bag-shaped cross section are formed in the axial direction on the outer circumference of the rotor core, and rotor bars having the same cross section as the slot are inserted into these slots, and both ends of these rotor bars are , in a squirrel-cage blade conductive motor equipped with a squirrel-cage rotor connected by silver brazing or welding with a short-circuit ring having a slot with the same shape and cross-section as the rotor bar on its outer periphery, the rotor bar and the short-circuit ring are connected to each other by silver brazing or welding. A flesh portion is formed on the short-circuit ring side at the lower contact portion with the end face on the rotor core side, and the flesh portion and the rotor bar are connected by silver brazing or welding.

(Function) Therefore, in the squirrel-cage blade conductive motor equipped with the rotor of the present invention, by forming the flesh part on the short-circuit ring, the fillet part of the silver brazing or welding with the rotor bar can be made on both sides and It can also be formed on the lower surface of the meat part, increasing the reliability of silver brazing or welding, and by forming the meat part below the maximum stress point, stress concentration due to bending can be alleviated.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an example of the configuration of a rotor in a squirrel-cage blade conductive motor according to the present invention, and FIG. 2 is a cross-sectional view taken along line X-X in FIG.
It is a cross-sectional view showing a portion, and the same elements as in FIGS. 3 to 5 are given the same reference numerals, and the explanation thereof is omitted, and only the different portions will be described here.

That is, in this embodiment, the rotor bar 3 in FIG.
A between
By forming a flesh part B on the short-circuit ring 4 side over the entire circumference of the point lower contact part, a corner part is formed between both sides of the rotor bar 3 and the corner with the flesh part B, as shown in the figure. , this flesh portion B and the rotor bar 3 are connected by silver brazing or welding.

In the squirrel-cage blade conductive motor equipped with the rotor configured as described above, by forming the flesh portion B in the short-circuit ring 4, the fillet portion for silver brazing or welding with the rotor bar 3 is prevented. , can be formed on both sides and on the underside of the flesh part B, increasing the reliability of silver brazing or welding.

This prevents insufficient electrical contact between the rotor bar 3 and the short-circuit ring 4, which causes the rotor bar 3 to vibrate due to electromagnetic vibration and rotational vibration, causing breakage of the rotor bar 3. There will be nothing to do. Also, the maximum stress point A
By forming the flesh part B at the lower part of the back side of the short-circuit ring 4, stress concentration due to bending can be alleviated. As a result, accidents such as breakage of the rotor bar 3 at this point will not occur.

As described above, in this embodiment, a cylindrical rotor core 2 formed by press-fitting a laminated body of a plurality of ring-shaped silicon steel plates into the rotating shaft 1 has a cross section in the axial direction. A plurality of bag-shaped slots are formed, rotor bars 3 having the same cross section as the slot are inserted into the slots, and both ends of the rotor bars 3 are inserted into the slots with the same cross section as the rotor bar 3. In a squirrel-cage blade conductive motor equipped with a squirrel-cage rotor connected by silver brazing or welding to a short-circuit ring 4 having slots formed on the outer periphery, the rotor bar 3 and the end surface of the short-circuit ring 4 on the rotor core 2 side are connected to each other by silver brazing or welding. A flesh portion B is formed on the short-circuit ring side at the lower contact portion of the rotor bar 3, and the flesh portion B and the rotor bar 3 are connected by silver brazing or welding.

Therefore, the reliability of silver brazing or welding between the rotor bar 3 and the short-circuit ring 4 and the brazing or weldability are improved, and the stress concentration at the maximum stress point A of the rotor bar 3 is alleviated, so that the rotation This makes it possible to prevent the child bar 3 from breaking.

[Effects of the Invention] As explained above, according to the present invention, a meat portion is formed on the short-circuit ring side at the lower contact portion between the rotor bar and the end face of the short-circuit ring on the iron core side, and the meat portion and the rotor bar are connected to each other. Since these are connected by silver q-plating or welding, the reliability and brazing or weldability of silver brazing or welding between the rotor bar and the short-circuit ring are improved, and the stress at the maximum stress point of the rotor bar is improved. It is possible to provide a squirrel-cage blade conductive motor equipped with a rotor that can alleviate stress concentration and prevent rotor bar breakage accidents.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a rotor in a squirrel-cage blade conductive motor according to the present invention, and FIG.
-A sectional view showing the X portion, FIG. 3 is a longitudinal sectional view showing a configuration example of a squirrel cage blade conductive motor, FIG. 4 is a sectional view showing the main part in FIG. 3, and FIG. 5 is a Y in FIG. It is a sectional view showing a -Y portion. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2... Rotor core, 3... Rotor bar 4... Short circuit ring, 5, 6... Iron core holder, 7...
Retaining ring, 8, convex portion, 9, casing, 1o...
Stator core, 11... Stator coil, A... Maximum stress point, B... Flesh part. Applicant's agent Patent attorney Takehiko Suzue Figure 4

Claims (1)

[Claims] A plurality of slots with bag-shaped cross sections are formed in the axial direction on the outer periphery of a cylindrical rotor core made by press-fitting a laminated body of ring-shaped silicon steel plates onto a rotating shaft. Insert rotor bars with the same cross-section shape as the slot cross-section into the slots, and connect both ends of these rotor bars by silver brazing or welding with short-circuit rings each having a slot with the same cross-section shape as the rotor bar on the outer periphery. In a squirrel cage induction motor equipped with a connected squirrel cage rotor, a flesh portion is formed on the short circuit ring side at the lower contact portion between the rotor bar and the end surface of the short circuit ring on the rotor core side, and the flesh portion and A squirrel cage induction motor, characterized in that the rotor bar is connected to the rotor bar by silver brazing or welding.