JPH01160340A - Squirrel-cage induction motor for rolling stock - Google Patents

Abstract

PURPOSE:To facilitate the installation of balancing pieces, by forming an annular balancing groove circumferentially for two-piece type balancing pieces on the outside end face in the axial direction of a holding ring presser. CONSTITUTION:An end connection ring 9 is silver-soldered to both ends of a rotor bar 8 forcibly inserted into a plurality to slots on the outside circumference of a rotor core 6. On the outside circumference of this end connection ring 9 a protection ring 10 is installed. A holding ring presser 23 is stickingly fitted to the external end face in the axial direction of the end connection ring 9. An annular balancing groove 23d is formed in the circumferential direction of this holding ring 23 with the external end face of a main body section 23a and in- and external projected barbes, into which sets of two-piece type balancing pieces 19A and 19B are inserted and fixed by pressure with a set screw 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a squirrel-cage induction motor used as a motor of a railway vehicle or the like.

(Prior Art) In general, this type of vehicle squirrel cage induction motor has a stator core 2 attached to the inner circumference of the stator side casing 1, as shown in FIG.
and stator coil 3 are installed. On the other hand, a rotor shaft 5 is attached, rotatably supported by bearings 4a and 4b provided at both ends of the casing 1, and a rotor core 6 made of a laminated plate holds both ends of the rotor shaft 5. It is held and fixed by 7. In addition, a plurality of slots 6 are provided at equal pitches in the circumferential direction near the outer periphery of the rotor core 6.
A is formed, and rotor bars 8 are attached to these by press-fitting, and end rings 9 are attached to both ends of these rotor bars 8 by silver brazing, respectively.

A retaining ring 10 made of a non-magnetic material is provided on the outer peripheral surface of this end ring 9.
is attached, and in order to fix this retaining ring 10, a retaining ring presser 11 made of a non-magnetic material is tightened and fixed by bolts 12 on the axially outer end surface of the end ring 9, and furthermore, the end ring 9 An end ring support 13 also made of a non-magnetic material is fixed to the outer end surface of the core holder 7 with a bolt 14 in order to restrain the displacement of the core holder 7 from the inner circumferential side. For self-ventilation cooling, this electric motor has an outside air suction port 15 near one end of the casing 1 and an exhaust port 16 near the other end. A cooling ffJ wind tunnel 17 is formed over the rotor shaft 3, and a general cooling fan 18 is attached to the rotor shaft 3 so as to rotate together with the rotor shaft 3.

Then, the rotor rotates due to the energization, and the ventilation cooling fan 18 rotates together with the rotor shaft 5.

With this, outside air is taken into the cabin from the suction port 15,
The air is passed through the gap G between the stator core 2 and the rotor core 6 and the cooling air tunnel 17, and the air is discharged through the exhaust port 16 while cooling the inside of the machine.
It is now being discharged to the outside.

In such a squirrel cage induction motor for a vehicle, in order to maintain rotational (dynamic) balance of the rotor, a balance groove 13a is formed in the end ring support 13 in an annular shape in the circumferential direction. As shown in FIGS. 3 and 4, a plurality of pairs of two-part balance pieces 19A and 19B are provided in the balance according to the need for balance correction. In other words, the balance groove 13a is a dovetail groove having a substantially trapezoidal cross section as shown in FIG.
As shown in FIG. 5, the pair of balance pieces 19A and 19B each have a shape in which a trapezoid body is vertically divided into two parts, and each has a female thread 19a at the center of the opposing inner surfaces.

19b. After inserting the pair of balance pieces 19A and 19B into the balance groove 13a at the position where the balance should be corrected,
, 19b, the two balance pieces 19A, 19B are pushed apart so as to repel each other and are crimped and fixed to both sides of the balance groove 3a.

In addition, in the case of a squirrel cage induction motor in which the above-mentioned end ring support 13 is not provided, a balance groove is formed in the outer end surface of the core holder 7.

(Problems to be Solved by the Invention) Incidentally, in the squirrel-cage type induction motor for vehicles described above, the configuration and size of the rotor differ depending on various specifications. The diameter of the circumference of the balance groove 13a, which is formed as shown in FIG.

On the other hand, the balance pieces 19A and 19B, which have traditionally been used for installation in rotating electrical equipment for railway vehicles, have been standardized into three types of quality and size: large, medium and small. The balance groove 13a is not machined to match the circumference of the balance groove 13a. That is, both inner surfaces of the balance groove 13a are curved according to the diameter, but both sides of the balance pieces 19A and 19B are linear. For this reason, both side surfaces of the balance pieces 19A and 19B are locally pressed against and fixed to the inner surfaces of the balance groove 138 so as to be supported at three points, as shown in FIG.

This means that when the diameter of the balance groove 13a becomes smaller than a certain range, the balance piece 19A,
19B does not fit properly, and the hexagon socket set screw 20 cannot be screwed in between them. For example, if the width H of the balance pieces 19A, 19B is 16M, the minimum diameter of the balance groove 13a to which these can be attached is 150m.
Therefore, the balance pieces 19A and 19B cannot be installed in a balance groove having a smaller diameter than this.

Therefore, railway vehicles, small subways and trams,
Because small bogies and small-diameter wheels are used, the outer diameter of the squirrel-cage induction motor used for these is smaller than that of general railway vehicles, and as a result, the rotor is also small in diameter, so the diameter of the balance groove is reduced. is below the aforementioned 150m+, balance piece 19A.

It was impossible to install 19B.

Therefore, in order to solve this problem, a balance groove may be formed in the large-diameter end ring 9 disposed on the outer periphery of the end ring support 13 and the core presser 7, or a balance groove may be formed in the large diameter end ring 9 as shown in FIG. Using the road-shaped retaining ring 21, the balance groove 21 is attached to this.
It is conceivable to form a balance ring with a balance ring or add a new balance ring with a balance groove. however,
Forming a balance groove in the first end ring 9 causes a problem in terms of electrical characteristics since the cross-sectional area of the end ring 9 is reduced.

Further, forming the balance groove 21a in the retaining ring 21 means that
The retaining ring 21 itself is made of non-magnetic and expensive alloy steel, and if it were to have the cross-sectional shape as shown in FIG. 7, there would be a problem in that the cost of the material would increase significantly. Furthermore, adding a new balance ring requires extra space for installation, and in the case of electric motors for railway vehicles, there are severe dimensional restrictions, so it must be installed in the narrow space between the rotor core and the bearing inside the machine. It is very difficult to do so, and there is a problem in that it obstructs the ventilation of cooling air.

The present invention was developed in view of the above circumstances, and even in small-diameter squirrel cage induction motors for vehicles in which only a balance groove with a diameter of 15011Il or less can be formed in the end ring bundle or core holder.
It does not cause problems with electrical characteristics, increases in price, space problems, or even obstruction of cooling air.
An object of the present invention is to provide a squirrel cage induction motor for a vehicle that has a balance groove in which a conventionally standardized balance piece can be attached.

[Structure of the invention]

(Means for solving the problem) In order to achieve the above object, the squirrel cage induction motor for a vehicle of the present invention has a ring-shaped retaining ring bolted to the axially outer end surface of the end rings at both ends of the rotor bar. It is characterized in that a balance groove for attaching a two-part balance piece is formed in an annular shape in the circumferential direction on the outer end surface of the presser foot.

(Function) With the above configuration, even in small-diameter squirrel cage induction motors for vehicles, the balance groove is formed in the large-diameter retaining ring holder, which is placed on the outer periphery of the end-circuit ring bundle and core holder, so that the balance is balanced. The groove can have a diameter of 150 mm or more, so that a conventionally standardized balance piece can be easily installed to reliably correct the amount of rotational balance. Moreover, the balance groove was formed in the retaining ring holder as described above, without forming it in the end ring or retaining ring, or adding a new balance ring, so there were no problems with electrical characteristics or an increase in price. This eliminates problems such as space problems and ventilation obstruction of cooling air.

(Example) An example of the present invention will be described below with reference to FIG. In the drawings, Chiang has attached the same reference numerals to the same components as those shown in FIG. 2 and subsequent figures to simplify the explanation.

Here, end rings 9 are silver-brazed to both ends of the rotor bars 8 which are press-fitted into a plurality of slots 6a on the outer periphery of the rotor core 6, and the outer periphery of the end rings 9 is made of a non-magnetic material. The retaining ring 10 is attached, and a ring-shaped retaining ring presser 23 is fixed to the outer end surface of the end ring 9 in the axial direction by a bolt 12 to press and fix the retaining ring 10 as in the conventional case. The structure consists of groove-forming protrusions 23b and 23c that protrude into two inner and outer grooves on the outer peripheral half of the outer end face in the direction, and the outer end face of the main body portion 23a and the inner and outer protrusions 23b.

23c, a dovetail balance groove 23d extending annularly in the circumferential direction is formed. A plurality of pairs of two-part balance pieces 19A and 19B are inserted into this balance groove 23d in accordance with the need for balance correction as in the past, and hexagon socket set screws are inserted into the female threaded portions 19a and 19b of each pair. It is crimped and fixed by screwing in 20.

Therefore, with the above-mentioned configuration, even if it is a squirrel cage induction motor for small diameter vehicles used for small subways, streetcars, etc., in other words, a diameter of 150 mm is required for end ring binding and iron core holding.
Even in a small-diameter squirrel-cage induction motor for a vehicle where only a balance groove of m+ or less can be formed, the balance groove 23d is formed in the large-diameter retaining ring holder 23, which is placed on the outer periphery of the end-circuit ring bundle and core holder. The balance groove 23d has a diameter of 1
The length can be set to 505 m or more, and the rotational balance amount can be reliably corrected by easily attaching the conventionally standardized balance pieces 19A and 19B. Moreover, the balance groove 23d is formed in the holding 1 presser 23 as described above without forming it in the end ring 9 or the retaining ring 10 or adding a new balance ring. There are no problems, no increase in price, no space problems, and no problems such as obstruction of cooling air.

〔Effect of the invention〕

Since the present invention has been made as described above, even in small diameter vehicle squirrel cage induction motors in which only a balance groove with a diameter of 150 #ll or less can be formed in the end-circuiting base cover or core holder, problems in electrical characteristics can be solved. It is possible to secure a balance groove in which a conventionally standardized balance piece can be installed, and to correct the rotational balance of the rotor without incurring problems such as an increase in price, space problems, or obstruction of ventilation of cooling air. It becomes something that can be made effective.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main valve showing one embodiment of the present invention;
3 is an enlarged sectional view of a part of FIG. 2, FIG. 4 is a view taken along the line IV-IV in FIG. 3, and FIG. ) and FIG. 5(b) are a front view and a side view of a pair of balance pieces, FIG. 6 is a diagram showing the state of the balance piece being crimped against the balance groove, and FIG. 7 is a conventional example in which a balance groove is formed in the retaining ring. FIG. 6... Rotor core, 6a... Slot, 8... Rotor bar, 9... End ring, 10... Retaining ring, 23...
...Holding 1 presser, 19A, 19B...Balance piece, 23d...Balance groove. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 ■ Figure 3 Figure 4

Claims (1)

[Claims] A rotor bar press-fitted into a plurality of slots on the outer periphery of the rotor core, an end ring soldered with silver at both ends of these rotor bars, and a retaining ring attached to the outer periphery of the end ring. , a squirrel-cage induction motor for a vehicle equipped with a ring-shaped retaining ring holder bolted to an axial outer end surface of an end ring; A squirrel cage induction motor for a vehicle, characterized in that a balance groove is formed in an annular manner in the circumferential direction.