JP4183814B2 - Cage electric motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cage motor.
[0002]
[Prior art]
Conventionally, a squirrel-cage motor is known as a motor that has a simple structure and is easy to handle.
[0003]
As shown in FIG. 4 and FIG. 5, for example, this squirrel-cage electric motor forms a stator core 12 by laminating donut-shaped iron cores 11 formed by punching thin silicon steel plates, and is formed on the stator core 12. A rotation in which a stator 1 formed by fitting a winding 14 in a slot 13 is disposed at a predetermined position in a cylindrical frame body 21 forming a frame 2 and an iron core 31 formed by punching a thin silicon steel plate is laminated. A rotor conductor 34 made of copper or aluminum rod is inserted into a slot 33 of the core 32, and both ends of the core 35 are connected to each other by a short-circuit wire. There is known a structure in which the brackets 22 and 23 arranged on the shaft are pivotally supported.
[0004]
In the conventional squirrel-cage motor, the stator 2 having a circular peripheral surface is arranged inside the cylindrical frame main body 22 via the rib 24 extending in the axial direction, and the shaft 35 of the rotor 3 is arranged. The cooling fan 4 mounted in the front position of the iron core 31 takes in outside air for cooling from an outside air inlet 25 formed in the bracket 22 of the frame 2, and the outer periphery of the frame body 21, the rib 24 and the stator core 12. The rotor 3 is cooled by passing through a cooling passage 26 formed by the surface 15 and discharging from a discharge port 27 formed in the bracket 23 located behind the frame 2.
[0005]
[Problems to be solved by the invention]
However, in the conventional squirrel-cage motor, the stator core 12 that forms the stator 2 with which the passing cooling air contacts is formed by a donut-shaped iron core 11, and its outer peripheral surface is circular, and the heat radiation area is small. The heat dissipation efficiency was not good.
[0006]
In order to improve the efficiency of heat dissipation, it is conceivable to install a large-diameter cooling fan 4. However, the efficiency of the motor is reduced due to the increase in diameter, and noise generated by the rotation of the fan 4 is a problem. Become.
[0007]
Further, it is conceivable to increase the intake amount of the cooling air by increasing the outside air intake 25 formed in the bracket 22 of the frame 2, but at the same time, dust that has entered the stator 2 and the rotor 3 from the outside air intake 25. There is also a problem that the insulation resistance is lowered due to adhesion.
[0008]
The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a high-efficiency, low-noise cage motor.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a frame by forming a plurality of air cooling grooves extending in the axial direction of the rotor and exposed at both end faces of the stator core on the outer peripheral surface of the stator core. The heat dissipating area on the outer peripheral surface of the stator core with which the cooling air passing therethrough comes into contact is increased to improve heat dissipation efficiency.
[0010]
In addition, a circular cylinder projects from the end surface of the stator on the cooling fan side, and a labyrinth structure is interposed between the edge of the circular cylinder and the outer peripheral edge of the cooling fan, thereby removing the outside air. Dust that has entered the frame mixed with outside air taken in from the inlet is prevented from adhering to the stator and the rotor and lowering the insulation resistance.
[0011]
Further, the cooling efficiency is increased by providing cooling blades on both the outside and inside of the cooling fan.
[0012]
Furthermore, noise reduction is achieved by attaching a sound absorbing material to the inner surface of the bracket on the anti-load side among the brackets positioned in front of the frame.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. The same components as those in the conventional example will be described with the same reference numerals.
[0014]
FIGS. 1 to 3 show one of the preferred embodiments of the present invention. As shown in FIG. 2, the stator core 12 has a substantially hollow gear-shaped core 11 formed by punching a thin silicon steel plate. Are formed on the outer peripheral surface 15 of the stator core 12, and a number of air cooling grooves 18 exposed at both end faces 16 and 17 are formed on the stator core 12. The stator 1 formed by fitting the winding 14 in the slot 13 is disposed in contact with the inner peripheral surface 28 of the cylindrical frame main body 21 forming the frame 2.
[0015]
The rotor 3 arranged in the stator 1 is made of a copper or aluminum rod in a slot 33 of a rotor core 32 in which an iron core 31 formed by punching a thin silicon steel plate is laminated, as in the conventional example. Brackets 22, 23 constituting the frame 2 are arranged by inserting shafts 35 on which a rotor 3, in which a rotor conductor 34 is inserted and both ends are connected with a short-circuited wire to form a cage 3, is disposed at both ends of the cylindrical frame body 21. It is installed with a pivot between them.
[0016]
Further, a cooling fan 4 is mounted at a position in front of the iron core 31 of the shaft 35 in the rotor 3. The cooling fan 4 that rotates along with the rotation of the rotor 3 causes the outside air to be on the opposite load side bracket 22 in the frame 2. Are taken into the frame 2 from the outside air intake 25 formed in the outer air inlet 25 and exposed to the inner peripheral surface 28 of the frame body 25 and the both end surfaces 16 and 17 formed on the outer peripheral surface 15 of the stator core 12. After passing through a cooling passage 26 formed between the groove 18 and the discharge port 27 formed in the bracket 23 on the load side of the frame 2, it is discharged.
[0017]
At this time, in the present embodiment, the outer peripheral surface 15 of the stator core 12 has a number of air cooling grooves 18 exposed on both end surfaces 16 and 17 serving as cooling passages 26, which are shown in FIGS. 4 and 5. Since the heat radiation area is larger than that of the outer peripheral surface 15 of the conventional circular stator core 12, higher radiation efficiency can be obtained.
[0018]
Further, in the present embodiment, a circular cylindrical body 51 concentric with the shaft 35 is projected on the cooling fan 4 side of the stator 11, that is, the end face 16 on the opposite side of the load, The labyrinth structure 5 is formed by the annular groove 53 formed on the inner surface of the outer peripheral edge 41 of the cooling fan 4.
[0019]
Therefore, the stator 1 and the rotor 3 are blocked from the outside air by the labyrinth structure 5, and the dust that has entered the frame 2 mixed with the outside air taken into the frame 2 from the outside air inlet 25 enters the stator 1 and the rotor. 3 and does not decrease the insulation resistance due to the adhesion of dust as in the prior art.
[0020]
Further, the cooling fan 4 is provided with a cooling blade 42 for introducing outside air into the cooling passage 26 on the outer side 41 and a cooling blade 43 for cooling the rotor 3 directly on the inner side. Not only can the rotor 3 be directly cooled, but the heated air in the frame 2 can be exchanged with the outside air through the cooling passage 26 very efficiently.
[0021]
In addition, a sound absorbing material 29 formed of, for example, a soft synthetic resin foam is attached to the front side of the frame 2, that is, the inner surface of the bracket 22 on the opposite load side. Therefore, generation of noise during rotation can be suppressed.
[0022]
【The invention's effect】
As described above, the present invention can sufficiently cool the heat generated in the stator core during rotation by increasing the heat radiation area on the outer peripheral surface of the stator core.
[0023]
In addition, a circular cylindrical body protrudes from an end surface of the stator on the cooling fan side, and a labyrinth structure is interposed between an edge of the circular cylindrical body and an outer peripheral edge of the cooling fan, whereby the stator In addition, since the rotor is sealed, dust that has entered the frame mixed with the outside air taken in from the outside air inlet is prevented from adhering to the stator and the rotor and lowering the insulation resistance.
[0024]
Furthermore, by providing cooling blades on both the outside and inside of the cooling fan, the cooling efficiency is increased, and a sound absorbing material is attached to the inner surface of the bracket on the opposite side of the bracket located in front of the frame. Reduce noise.
[0025]
Thus, the squirrel-cage electric motor according to the present invention can obtain a property close to that without incurring manufacturing costs like a completely sealed squirrel-cage motor, and is extremely practical. .
[Brief description of the drawings]
FIG. 1 is a partially broken explanatory view showing a preferred embodiment of the present invention.
2 is an exploded perspective view showing a fixed iron core used in the embodiment shown in FIG. 1. FIG.
FIG. 3 is an enlarged cross-sectional view of a part along the line AA in FIG. 1;
FIG. 4 is a perspective view with a part broken away showing a conventional example.
FIG. 5 is a cross-sectional view in which a part along line BB in FIG. 4 is omitted.
[Explanation of symbols]
1 Stator, 2 Frame, 3 Rotor, 4 Cooling Fan, 5 Labyrinth Structure, 12 Stator Core, 13 Slot, 14 Winding, 15 Outer Surface, 16 End Surface, 17 End Surface, 18 Groove, 21 Frame Body, 22 Side Plate , 23 Side plate, 25 Outside air inlet, 26 Cooling passage, 27 Outside air outlet, 29 Sound absorbing material, 35 shaft, 42 Cooling blade, 43 Cooling blade, 51 Circular cylinder

Claims (1)

A stator formed by fitting a winding into a slot formed in the stator core is arranged at a predetermined position in the frame, and a rotor conductor is placed in a slot of the core fixed to a shaft supported between both brackets of the frame. A rotor having a cage shape by connecting both ends of the plug with a short-circuit wire is disposed inside the stator, and a cooling fan is mounted in front of the rotor of the shaft, and the cooling fan is used to move the front of the frame. The outside air taken in from the outside air inlet formed in the bracket located in the bracket is discharged from the cooling passage formed between the stator and the frame from the outside air outlet formed in the bracket located behind the frame and fixed. so as to cool the child, the the outer circumferential surface of the stator core, are the number of grooves arranged exposed at both end faces of the stator core extends in the axial direction of the rotor gear Are formed on, the squirrel-cage motor in which these grooves to form the cooling passage, the cooling fan is a circular cylinder which is projecting from the end surface of the cooling fan side of the stator on the inner surface of the peripheral edge An annular groove for interposing a labyrinth structure is formed between the edge of the rotor and the stator and the rotor are isolated from the outside air to prevent the stator and the rotor from adhering to the dust from the outside air, and the cooling The fan is provided with a cooling blade for introducing outside air into the cooling passage on the outside, and a cooling blade for directly cooling the rotor that is blocked from outside air on the inside. A squirrel-cage electric motor which not only cools the child but also exchanges heated air in the frame with outside air through the cooling passage very efficiently .

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