JP2675741B2 - Open type rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open type rotating electric machine having improved cooling performance.

[0002]

2. Description of the Related Art FIG. 10 shows a conventional structure of an open type induction motor which is an open type rotary electric machine. In the figure, the outer shell 1 of the electric motor is composed of a tubular stator frame 2 and bearing brackets 3 (only one of which is shown) attached to both ends of the stator frame 2. Of these, the bearing bracket 3 has a bearing housing 3a formed in the center thereof, an intake port 3b formed around the bearing housing 3a, and an exhaust port 2a formed in the stator frame 2. ing.

A stator 4 is arranged on the inner peripheral portion of the stator frame 2. The stator 4 is composed of an annular stator core 5 fixed to the stator frame 2 and a stator winding 6 wound around a slot of the stator core 5.

A rotor 7 is arranged inside the stator 4. The rotor 7 includes a rotary shaft 9 supported by a bearing housing 3 a via a bearing 8, a rotor core 10 provided on the outer peripheral portion of the rotary shaft 9, and a plurality of rotor cores 10 provided on the rotor core 10. Rotor conductor 11, an end ring 12 provided at both ends of the rotor core 10 so as to short-circuit the rotor conductor 11, and a plurality of end rings 12 projecting outward from the end ring 12 in the axial direction. It is composed of the fins 13.

An annular baffle plate 14 is provided inside the bearing bracket 3.
Is arranged so that the end portion 14a on the inner peripheral side is close to the fin 13.

In this type of open induction motor, the rotor core 10 and the stator core 5 have iron loss, the rotor conductor 11, the end ring 12 and the stator winding 6 have copper loss, and the bearing 8 has friction. Loss, and wind loss occurs on the surfaces of the fins 13 and the rotor 7.

On the other hand, due to the air blowing action (pressurizing effect) due to the rotation of the fins 13, the outside air outside the outer shell 1 is sucked into the outer shell 1 from the intake port 3b as shown by the arrow, and the air is guided by the baffle plate 14. And the bearing housing 3a, and the flow passage B between the baffle plate 14 and the end ring 12 to the stator 4 side. The air sent to the side of the stator 4 flows to the flow path C side between the baffle plate 14 and the end 6a of the stator winding 6, the stator core 5 and the straight portion 6b of the stator winding 6. To the flow path D between them, and join at the back part of the stator winding 6, and then pass through the flow path E at the back part of the stator core 5, and from the exhaust port 2a of the stator frame 2 to the outer shell 1 Is discharged to the outside.

Here, most of the loss (heat) generated in the portion of the stator winding 6 arranged in the slot of the stator core 5 is radiated to the air flowing through the flow path D, and
The loss generated in the outer portion of the stator core 5 in the stator winding 6 is mainly radiated to the air flowing in the flow paths C and D. Further, the loss generated in the stator core 5 is mainly radiated to the air flowing through the back portion of the stator winding 6 and the flow path E, and the rotor core 5, the rotor conductor 11, and the end ring 12 are also removed.
Most of the loss generated in 1 is radiated to the air flowing in the flow path B.

In the ventilation cooling system in which most of the loss generated in the outer shell 1 is radiated to the outside air sucked into the outer shell 1 as described above, the air flow from the intake air to the exhaust air is cooled. is important. In the ventilation system of the open induction motor having the above-described structure, the following pressure loss occurs in the main flow path from the intake port 3b to the exhaust port 2a.

[0010]

[Table 1]

Among these, the flow path having a relatively large pressure loss will be described in detail. In the flow path A between the baffle plate 14 and the bearing housing 3a, the air sucked into the outer shell 1 is rapidly contracted and then immediately expanded, and its flow speed is rapidly increased. Also, the pressure is slowed down and a pressure loss is generated as if passing through the orifice. Further, in the flow path C between the baffle plate 14 and the end portion 6a of the stator winding 6, air flows around the end portion 6a of the stator winding 6 and the pressure loss such that the air passes through the sluice valve. Occurs. Table 2 shows a list of pressure loss in the conventional open type induction motor. From this table 2,
It can be seen that the loss in channel A and channel C is extremely large.

[0012]

[Table 2]

The flow rate of air (wind) is determined by the balance between the total of these pressure losses and the air blowing action (pressurizing effect) of the fins 13. FIG. 11 shows the pressure-flow rate characteristic. In the figure, R indicates a general ventilation resistance curve. It operates at the intersection of the characteristic curve and the ventilation resistance curve R, the flow rate Qa, and the pressure Pa. That is, the total pressure loss and the generated pressure of the fins 13 are balanced when they become equal. On the other hand, the boosting effect of the fin 13 is expressed by the following equation.

[0014]

(Equation 1) The relationship with the operating point pressure Pa is

[0015]

(Equation 2) The operating point pressure Pa is

[0016]

(Equation 3) therefore,

[0017]

(Equation 4)

Based on these relationships, in order to operate in the high flow rate region, the sum of the pressure loss in each flow path may be reduced and the ventilation resistance curve R in FIG. 11 may be moved to the R1 side. If a high flow rate is obtained, the heat transfer coefficient of each heat transfer surface will increase, the temperature of the air will also decrease, and the temperature rise value in the outer shell 1 can be reduced, reducing the machine size (outer dimensions of the electric motor). can do.

[0019]

By the way, in the open type induction motor having the above-mentioned structure, generally, the peripheral speed of the fins 13 cannot be set so high that Po is satisfied.
Is not large and therefore the flow rate is not high. Therefore, in order to obtain a high flow rate, as described above, the pressure loss in each flow path may be reduced and the slope of the ventilation resistance curve R may be reduced. However, if the pressure loss is reduced and the flow rate is increased by increasing the cross-sectional area of each flow path to reduce the flow velocity, the machine size will increase. Therefore, an object of the present invention is to provide an open-type rotating electric machine that can obtain a high flow rate and can improve the cooling performance without increasing the machine size.

[0020]

SUMMARY OF THE INVENTION The present invention is constructed by mounting bearing brackets having bearing housings at both ends of a tubular stator frame, of which the bearing bracket is provided with an intake port and a stator. An outer shell having an exhaust port formed in the frame, a stator core provided in an inner peripheral portion of the stator frame and having an annular shape, and a stator winding provided in the stator core,
A rotary shaft rotatably supported in the bearing housing via bearings, a rotor core provided on the outer peripheral portion of the rotary shaft and arranged inside the stator core, and both end portions of the rotor core. An end ring provided on the end ring, a fin projecting outwardly in the axial direction on the end ring, and an end portion on the inner peripheral side inside the bearing bracket so as to be close to the tip end portion of the fin. An annular baffle plate that is arranged is provided, and by the air blowing action that accompanies the rotation of the fins, the air outside the outer shell is sucked into the outer shell from the intake port,
In the open-type rotating electric machine configured to discharge the air in the outer shell to the outside from the exhaust port, the minimum ventilation cross-sectional area between the end portion of the stator winding and the baffle plate is Sc, When the minimum ventilation cross-sectional area between the wind plate and the bearing housing is Sa, Sc / (Sc + Sa) is set to about 0.4.

In this case, it is preferable that the outer peripheral portion of the end portion inside the outer shell of the bearing housing is formed in an arc shape having a radius of the thickness dimension of the bearing housing. When a connecting portion is provided at the end of the stator winding, the connecting portion should be
It is preferable to arrange it on the outer peripheral side of the stator winding.

[0022]

When the flow velocities of the flow passages are equal, the orifice loss generated when passing through the flow passage between the bearing housing and the baffle plate is generated between the end portion of the stator winding and the baffle plate. It is larger than the gate valve loss that occurs when passing through the flow path. Therefore, the relationship between the minimum ventilation cross-sectional area Sc between the end portion of the stator winding and the baffle plate and the minimum ventilation cross-sectional area Sa between the baffle plate and the bearing housing is Sc / (Sc + Sa) Is about 0.4
By setting so that the flow rate can be increased, as is clear from the experimental result (see FIG. 4).

By forming the outer peripheral portion of the end portion inside the outer shell of the bearing housing in an arc shape, the air flow becomes smooth, pressure loss is reduced, and the flow rate can be further increased. Further, the pressure loss can be reduced and the flow rate can be further increased by arranging the connecting portion of the stator winding on the outer peripheral side.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 1 showing the configuration of an open induction motor that is an open rotary electric machine, an outer shell 21 of the electric motor includes a cylindrical stator frame 22 and bearing brackets attached to both ends of the stator frame 22. 23 (only one is shown). Of these, the bearing bracket 23 has a bearing housing 23a formed in the center thereof, an intake port 23b formed around the bearing housing 23a, and an exhaust port 22a formed in the stator frame 22. ing.

A stator 24 is provided on the inner peripheral portion of the stator frame 22.
Are arranged. The stator 24 is composed of an annular stator core 25 fixed to the stator frame 22 and a stator winding 26 wound in a slot of the stator core 25.

A rotor 27 is arranged inside the stator 24. The rotor 27 includes the bearing 2 in the bearing housing 23a.
8, a rotary shaft 29 supported by the rotor 8, a rotor core 30 provided on the outer periphery of the rotary shaft 29, a plurality of rotor conductors 31 provided on the rotor core 30, and a rotor core. An end ring 32 provided so as to short-circuit the rotor conductor 31 at both ends of the end ring 30 and the end ring 3
A plurality of fins 3 projecting outward from the axial direction 2
And 3.

An annular baffle plate 34 is provided inside the bearing bracket 23.
Is arranged such that the end portion 34a on the inner peripheral side is close to the fin 33.

Here, the minimum ventilation cross-sectional area between the end portion 26a of the stator winding 26 and the baffle plate 34 is shown by the diagonal lines in FIG. 2, and if this minimum ventilation cross-sectional area is Sc, This is expressed by the following equation.

[0029]

(Equation 5)

Further, the baffle plate 34 and the bearing housing 23a
The minimum ventilation cross-sectional area between and is shown by the diagonal lines in FIG. 3, and when this minimum ventilation cross-sectional area is Sa, this is expressed by the following equation.

[0031]

(Equation 6)

In this embodiment, Sc / (Sc + S
The value of a) is set to be about 0.4. In the above-described configuration, the fins 33 rotate as the rotor 27 rotates, and the air blowing action (pressurizing effect) of the fins 33 causes the outside air outside the outer shell 21 to flow from the intake port 23b into the outer shell 21 as shown by the arrow. Is sucked into the stator 24 side through the flow path A between the baffle plate 34 and the bearing housing 23a and the flow path B between the baffle plate 34 and the end ring 32. The air sent to the side of the stator 24 has the flow path C side between the air guide plate 34 and the end 26a of the stator winding 26, the stator core 25 and the straight portion 26b of the stator winding 26. To the outer shell 21 from the exhaust port 22a of the stator frame 22 through the passage E on the back of the stator core 25. Is discharged to the outside.

Here, in FIG. 4, Sc / (Sc + Sa)
The experimental result of the relationship between the ratio β and the flow rate is shown. As is clear from FIG. 4, the flow rate is maximum when the ratio β is about 0.4, so that the pressure loss can be reduced as much as possible and the cooling performance can be improved. Cooling flow path (ventilation flow path) of this type of open-ended induction motor
In Table 2, as shown in Table 2 above,
Fiss loss and sluice valve loss dominate, and other
Loss, e.g. inlet loss at inlet, exhaust loss at outlet,
The ratio of bending loss around the coil end is extremely small.
It is quiet. Therefore, in this embodiment, the stator winding is
Minimum ventilation cross-sectional area between the end portion 26a of 26 and the baffle plate 34
The maximum distance between Sc and the baffle plate 34 and the bearing housing 23a.
The ratio β of the cross-sectional area with the small ventilation cross-sectional area Sa is set as described above.
By setting it to about 0.4, the cooling of the open induction motor
These orifices, in which the pressure loss is dominant in the discharge channel,
Loss and gate valve loss to be minimized
This also minimizes the overall pressure loss.
You will be able to.

FIG. 5 shows a second embodiment of the present invention, which is different from the above-described first embodiment in the following points.
That is, the end portion 26a of the stator winding 26 projects more toward the air guide plate 34 side than in the first embodiment, and the end portion 23c inside the outer shell 21 of the bearing housing 23a.
However, it protrudes to the inside of the outer shell 21 as compared with the case of the first embodiment.

Here, the minimum ventilation cross-sectional area between the end portion 26a of the stator winding 26 and the baffle plate 34 is shown by the diagonal lines in FIG. 6, and when this minimum ventilation cross-sectional area is Sc, This is expressed by the following equation.

[0036]

(Equation 7)

Further, the baffle plate 34 and the bearing housing 23a
The minimum ventilation cross-sectional area between and becomes as shown by the diagonal lines in FIG. 7, and when this minimum ventilation cross-sectional area is Sa, this is expressed by the following equation.

[0038]

(Equation 8)

Also in this second embodiment, Sc / (S
The value of (c + Sa) is set to about 0.4. Also in the second embodiment as described above, the same operational effects as in the first embodiment can be obtained.

FIG. 8 shows a third embodiment of the present invention, which is different from the first embodiment in the following points. That is, the outer peripheral portion 23d of the end portion inside the outer shell 21 of the bearing housing 23a is formed in an arc shape having a radius of the thickness dimension of the bearing housing 23a. According to the third embodiment, the outer peripheral portion 23 of the end portion of the bearing housing 23a is formed.
The flow of air through d is smoothed, pressure loss is reduced, and the flow rate can be further increased.

FIG. 9 shows a fourth embodiment of the present invention, which is different from the first embodiment in the following points. That is, when the connecting portion 35 is provided at the end portion 26 a of the stator winding 26, the connecting portion 35 is arranged on the outer peripheral side by about ½ of the thickness of the stator winding 26. According to the fourth embodiment, the flow of air through the end portion 26a of the stator winding 26 is smoother than that in the case where the connecting portion 35 is arranged at the inner peripheral portion or the central portion of the stator winding 26. Therefore, the pressure loss is reduced, and the flow rate can be further increased.

[0042]

According to the open type rotating electric machine of the first aspect, the minimum ventilation cross-sectional area Sc between the end of the stator winding and the baffle plate, and between the baffle plate and the bearing housing. By setting the relationship between the minimum ventilation cross-sectional area Sa of Sc such that Sc / (Sc + Sa) is approximately 0.4, this type of open-type rotary electric
The dominant loss of pressure loss in the cooling passage of the machine
Certain orifice loss and sluice valve loss should be minimized.
Therefore, the main pressure loss from the intake port to the exhaust port can be reduced and a high flow rate can be obtained without increasing the machine size, and the cooling performance can be improved.

According to the open type rotating electric machine of the second aspect, the outer peripheral portion of the inner end of the outer shell of the bearing housing is formed in an arc shape, whereby the air flow becomes smooth and the pressure loss is reduced. The flow rate can be further increased.

According to the open type rotating electric machine of the third aspect, by disposing the connecting portion of the stator winding on the outer peripheral side, the pressure loss can be reduced and the flow rate can be further increased. it can.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a first embodiment of the present invention.

FIG. 2 is a diagram schematically showing a minimum ventilation cross-sectional area Sc between an end portion of a stator winding and a baffle plate.

FIG. 3 is a diagram schematically showing a minimum ventilation cross-sectional area Sa between a baffle plate and a bearing housing.

FIG. 4 is a diagram showing a relationship between a ratio β of Sc / (Sc + Sa) and a flow rate.

FIG. 5 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 6 is a view corresponding to FIG.

FIG. 7 is a diagram corresponding to FIG. 3;

FIG. 8 is a vertical cross-sectional view of a main part showing a third embodiment of the present invention.

FIG. 9 is a vertical cross-sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 10 is a diagram corresponding to FIG. 1 showing a conventional configuration.

FIG. 11 is a diagram showing the relationship between pressure and flow rate.

[Explanation of symbols]

21 is an outer shell, 22 is a stator frame, 22a is an exhaust port, 23 is a bearing bracket, 23a is a bearing housing, 23b is an inlet port, 23c is an end portion, 23c is an end portion outer peripheral portion, 25 is a stator core, 26 Is a stator winding, 26a is an end portion, 28 is a bearing, 29 is a rotating shaft, 30 is a rotor core, 32 is an end ring, 33 is a fin, 34 is a baffle plate, and 34a is an end portion.

Claims (3)

(57) [Claims] 1. A structure in which a bearing bracket having a bearing housing is attached to both ends of a cylindrical stator frame, and an intake port is formed in the bearing bracket and an exhaust port is formed in the stator frame. A shell, an annular stator core provided in the inner peripheral portion of the stator frame, a stator winding provided on the stator core, and a bearing rotatably supported in the bearing housing via a bearing. The rotating shaft, the rotor core provided on the outer peripheral portion of the rotating shaft and arranged inside the stator core, the end rings provided at both ends of the rotor core, and the end ring. A fin protruding toward the outer side in the axial direction, and an annular baffle plate disposed inside the bearing bracket so that the end portion on the inner peripheral side is close to the tip portion of the fin. Provided, a blowing action associated with the rotation of the fins In the open-type rotating electric machine configured to suck the air outside the outer shell into the outer shell from the intake port and to discharge the air inside the outer shell to the outside through the exhaust port, the stator winding Sc / (Sc + Sa) is about 0. where Sc is the minimum ventilation cross-sectional area between the end of the air guide plate and the air guide plate and Sa is the minimum ventilation cross-sectional area between the air guide plate and the bearing housing. An open type rotating electric machine characterized by being set to 4. 2. The open-type rotating electric machine according to claim 1, wherein an outer peripheral portion of an end portion inside the outer shell of the bearing housing is formed in an arc shape having a radius of a thickness dimension of the bearing housing. 3. The open type rotating machine according to claim 1, wherein the stator winding has a connecting portion at an end thereof, and the connecting portion is arranged on an outer peripheral side of the stator winding. Electric machinery.