JP6869856B2 - Electric motor for driving railway vehicles and railway vehicles using it - Google Patents

Description

The present invention relates to a rotary electric machine, and more particularly to a rotary electric machine that is cooled by using air.

Rotating electric machines are caused by eddy current loss and Joule loss when converting an electrical input into an electrical output as an electric motor, or when converting a mechanical input into an electrical output as a generator. And generate heat.

The upper limit temperature is specified for each material constituting the rotary electric machine, and it is necessary to cool each part so that the temperature of each part does not exceed the upper limit temperature when operating as an electric motor or a generator.

The air cooling method is widely used as the cooling method for rotary electric machines.
The air cooling method is a cooling method in which heat is removed and cooled by directly or indirectly applying air to the heat generating portion of the rotary electric machine.
Further, the air cooling method can be classified into a forced air cooling method in which air for cooling is forcibly flowed by using a device such as a fan and a natural air cooling method in which heat is dissipated by natural convection without using a device such as a fan.

The rotary electric machine using the conventional forced air cooling system has a structure in which the rotary electric machine is cooled by circulating the air in the rotary electric machine by a ventilation fan that rotates integrally with the rotor of the rotary electric machine.

It is generally known that the performance of a fan is such that the air volume is proportional to the rotation speed of the fan and the required power is proportional to the cube of the rotation speed of the fan. Therefore, in a rotating electric machine in which the fan rotates integrally with the rotor, the air volume of the fan is proportional to the rotation speed of the rotor, and the power of the fan is proportional to the cube of the rotation speed of the rotor. Patent Document 1 is an example of such a rotary electric machine.

Japanese Unexamined Patent Publication No. 2013-126309

However, as shown in the equation (1), the loss of the rotary electric machine is obtained by the product of the rotation speed, the torque, and the reciprocal of the efficiency. Therefore, even if the rotation speed is high, the torque is small or the efficiency is high. Since the loss is small, the required cooling air volume may be small.
Loss of rotary electric machine = (rotation speed) x (torque) x (1 / efficiency-1) Equation (1)
For example, in a traction motor for driving a railway vehicle, there is a large loss during acceleration / deceleration between the time when the railway vehicle starts and accelerates from a stopped state and the time when the railway vehicle decelerates and stops from the cruising speed, and while traveling at the cruising speed The loss is small. However, at the cruising speed, since the rotation speed of the rotating electric machine is high, the cooling air volume is excessively large, which causes a decrease in efficiency due to excessive fan power and an increase in noise due to the excessive fan air volume.

An object of the present invention is to solve the above-mentioned problems and reduce an excessive amount of cooling air in an air-cooled rotary electric machine having a ventilation fan that rotates integrally with a rotor to provide fan power. The purpose is to reduce fan noise.

To give an example of the " motor for driving a railway vehicle " of the present invention for achieving the above object,
Frames for holding the stator, and a rotor that are opposed to each other via a predetermined gap on the inner diameter side of the stator, and a fan which rotates with the rotor and integrally made, the stator The fan is provided with a first flow path in the rotation axis direction provided between the stator core and a second flow path provided through the rotor core in the rotation axis direction, and the fan rotates. As a result, the cooling air is circulated and ventilated inside the motor through the first flow path and the second flow path , and the cooling air temperature is transmitted to the first flow path or the second flow path. A railroad vehicle drive motor characterized by having a variable throttle mechanism that increases the ventilation cross-sectional area of the flow path during rising acceleration / deceleration and decreases the ventilation cross-sectional area of the flow path when the cooling air temperature is low at cruising speed. Is.

According to the present invention, the amount of excess cooling air can be reduced, and fan power and fan noise can be reduced.

It is sectional drawing which shows the rotary electric machine of Example 1 of this invention. It is sectional drawing which shows the state of the drawing mechanism at a low temperature which shows the rotary electric machine of Example 1 of this invention. It is sectional drawing which shows the state of the throttle mechanism at a high temperature which shows the rotary electric machine of Example 1 of this invention. It is a schematic diagram which shows the effect of the rotary electric machine of Example 1 of this invention. It is sectional drawing which shows the modification of the rotary electric machine of Example 1 of this invention. It is sectional drawing which shows the other modification of the rotary electric machine of Example 1 of this invention. It is sectional drawing which shows the rotary electric machine of Example 2 of this invention. It is sectional drawing which shows the state at the time of low rotation of the diaphragm mechanism which shows the rotary electric machine of Example 2 of this invention. It is sectional drawing which shows the state at the time of high rotation of the diaphragm mechanism which shows the rotary electric machine of Example 2 of this invention. It is a schematic diagram which shows the effect of the rotary electric machine of Example 2 of this invention. It is sectional drawing which shows the modification of the rotary electric machine of Example 2 of this invention. It is sectional drawing which shows the other modification of the rotary electric machine of Example 2 of this invention. It is sectional drawing which shows the rotary electric machine of Example 3 of this invention. It is sectional drawing which shows the modification of the rotary electric machine of Example 3 of this invention. It is sectional drawing of the drawing mechanism at a low temperature which shows the rotary electric machine of Example 4 of this invention. It is sectional drawing of the drawing mechanism at a high temperature which shows the rotary electric machine of Example 4 of this invention. It is a schematic diagram of the vehicle which mounts the rotary electric machine of Example 5 of this invention. It is a schematic diagram under the vehicle floor when the rotary electric machine of the fifth embodiment of the present invention is mounted on a vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each figure for demonstrating the embodiment, the same constituent elements are given the same name and reference numeral as much as possible, and the repeated description thereof will be omitted.

The rotary electric machine of the first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 shows a cross-sectional view of a first embodiment in which the present invention is applied to an induction motor.
In the following description of the examples, the rotary electric motor to which the present invention is applied will be described as an induction motor, but the present invention is not particularly limited to this, and if it is a forced air-cooled type, other motors such as a permanent magnet type synchronous motor The same effect can be obtained by applying the present invention to an electric motor. Further, it can be applied not only to an electric motor but also to a generator.

The rotary electric machine 1 which is an induction motor is composed of a stator 2, a rotor 3, and a frame 4 for holding the stator.

The stator 2 is provided on the stator core 20 and the inner diameter side of the stator core 20, is formed at a predetermined interval in the circumferential direction, and is wound around a plurality of stator slots extending in the rotation axis direction. It is composed of a stator coil 22. An air flow path 301 for circulating the cooling air 6 in the rotary electric machine is provided between the frame 4 and the stator core 20, and a throttle mechanism 5 is installed at the outlet portion of the air flow path 301. There is.

Further, the rotor 3 is provided on the outer diameter side of the rotor core 30 and the rotor core 30 which are arranged so as to face the stator core 20 with a predetermined gap in the radial direction and are predetermined in the circumferential direction. A plurality of rotor bars 32, which are field members inserted into a plurality of rotor slots formed at intervals and extending in the direction of the rotation axis, and a conductor for short-circuiting each rotor bar 32 at both shaft ends. It is composed of an end ring 33, a retaining ring 34 for holding each rotor bar 32 and the end ring 33, and a shaft 36 into which the rotor core 30 is fitted. The shaft 36 is rotatably held by the bearing 37. Further, the rotor core 30 is provided with an air passage 302 that serves as a passage for the cooling air 6 so as to penetrate in the direction of the rotation axis.

Further, a fan 35 for ventilating the cooling air 6 is attached to the rotor 3, and the fan 35 rotates integrally with the rotor 3 to circulate and ventilate the cooling air 6 inside the rotating electric machine. The air in the rotating electric machine excited by the fan 35 that rotates integrally with the rotor 3 hits the stator coil end 23, slowly heats from the stator coil 22, and then between the frame 4 and the stator core 20. It flows through the provided air passage 301. The cooling air 6 is slowly heated from the stator core 20 and cooled by the frame 4 while flowing through the air passage 301. After passing through the throttle mechanism 5, the cooling air that has passed through the air passage 301 flows into the air passage 302 provided in the rotor core 30 and flows into the fan 35 again.

2 and 3 show a drawing mechanism 5 using a shape memory alloy.
FIG. 2 shows a state when the cooling air 6 passing through the throttle mechanism 5 is at a low temperature, and FIG. 3 is a state when the cooling air 6 is at a high temperature.

The drawing mechanism 5 is a flow path drawing attached between the first spring 51 made of a shape memory alloy, the second spring 52 made of a non-shape memory alloy, and the first spring 51 and the second spring 52. It is composed of a plate 53.
When the temperature of the cooling air 6 passing through the drawing mechanism 5 is low and lower than the transformation temperature of the shape memory alloy constituting the first spring 51, the first spring 51 is pushed by the second spring 52. The flow path narrowing plate 53 is pushed up. As a result, a part of the air passage 301 is blocked by the flow path narrowing plate 53, so that the ventilation cross-sectional area of the air passage becomes small.

On the other hand, when the cooling air temperature rises and becomes higher than the transformation temperature of the shape memory alloy constituting the first spring 51, the first spring 51 recovers to a preset shape as shown in FIG. The second spring 52 is pushed down, and the flow path narrowing plate 53 is pushed down. As a result, the ventilation cross-sectional area of the air passage 301 becomes wide. As a result, when the temperature of the cooling air is low, the ventilation cross-sectional area of the air passage 302 can be made small, and when the temperature of the cooling air is high, the ventilation cross-sectional area of the air passage 302 can be made large.

FIG. 4 is a diagram schematically showing the effect of this embodiment.
Upon cooling air at low temperature, the flow rate of air passage by a diaphragm mechanism - pressure characteristics represented by a curve passing through O-A, the operating point of the fan is the point A, the air volume becomes Q _A, the fan power is W _a at that time ..
When the temperature of the cooling air rises and the ventilation cross-sectional area of the flow path increases due to the throttle mechanism, the flow rate-pressure characteristic of the ventilation path changes to a curve passing through OB, and the operating point of the fan at that time is point B, The air volume is Q _B and the fan power is W _b .

When the throttle mechanism of this embodiment is not used, the flow rate-pressure characteristic of the ventilation path is always OB regardless of the temperature of the cooling air, so that the fan power is always W _b . That the throttle mechanism of the present embodiment, the air flow rate when the cooling air is cold reduced from Q _B to Q _A, the fan power can be reduced from W _b in W _a.

In FIG. 1, the throttle mechanism 5 is attached to the outlet side of the ventilation passage 301, but as a modification, it may be attached to the middle of the ventilation passage 301 as shown in FIG. 5 or to the inlet side as shown in FIG. The same effect can be obtained even if it is attached.

According to this embodiment, the amount of excess cooling air can be reduced, and the fan power and fan noise can be reduced.

The rotary electric machine of the second embodiment of the present invention will be described with reference to FIGS. 7 to 10.

FIG. 7 is a cross-sectional view of a second embodiment in which the present invention is applied to an induction motor.
The difference from the first embodiment is that the throttle mechanism 5 is provided from the ventilation path 301 between the frame 4 and the stator core 20 to the entrance of the ventilation path 302 provided in the rotor core 30.

FIG. 8 is a diagram showing a state of the diaphragm mechanism 5 of the second embodiment at a low rotation speed. The drawing mechanism 5 is composed of a first spring 51 and a flow path drawing plate 53, and the first spring 51 is made of a non-shape memory alloy. At low rotation speeds, the first spring 51 presses the flow path narrowing plate 53 against the lower side (inner diameter side of the rotor) to keep the ventilation cross-sectional area of the ventilation passage 302 wide.
On the other hand, FIG. 9 is a diagram showing a state of the diaphragm mechanism 5 of the second embodiment of the present invention at a high rotation speed. As the number of rotations of the rotor increases, centrifugal force acts upward (toward the outer diameter of the rotor) on the first spring 51 and the flow path partition plate 53, and the first spring 51 is contracted to partition the flow path. The plate 53 moves upward (outer diameter side of the rotor). As a result, the ventilation cross-sectional area of the rotor ventilation passage 302 becomes smaller.

FIG. 10 is a diagram schematically showing the effect of this embodiment.
When the rotation speed of the rotor is low (N1), the pressure loss characteristic of the ventilation path is represented by a curve passing through OB, the operating point of the fan is point C, the air volume at that time is Q _c , and the fan power is It becomes W _c.
When the rotation speed of the rotor becomes high (N2, N2> N1), the operating point of the fan is point _B , the air volume at that time is QB, and the fan power is It becomes W _b.
On the other hand, by providing the diaphragm mechanism of the present embodiment, changes to curve the pressure loss characteristics of the ventilation passage passes through the O-A, the operating point of the fan is the point A when the rotational speed N2, the fan air volume Q _A, fan power is _{W a.} As a result, compared with no throttle mechanism of the present embodiment, the fan airflow from Q _B to Q _A, the fan power can be reduced from W _b in W _a.

In FIG. 7, the throttle mechanism is provided on the inlet side of the ventilation passage 302 of the rotor, but as a modification, the middle of the ventilation passage 302 as shown in FIG. 11 and the outlet side of the ventilation passage as shown in FIG. The same effect can be obtained even if it is provided in.

According to this embodiment, the amount of excess cooling air can be reduced, and the fan power and fan noise can be reduced.

FIG. 13 is a cross-sectional view of a rotary electric machine showing a third embodiment of the present invention.
In this embodiment, the throttle mechanism 5 is provided in the ventilation passage 303 for the bearing cooling air. The fan 35 is provided with a blade 38 for cooling the bearing, and the fan 35 rotates together with the shaft 36 to generate bearing cooling air. By attaching the same throttle mechanism 5 as in the first embodiment shown in FIGS. 2 and 3 to the ventilation passage 303 for the bearing cooling air, the amount of ventilation at low temperature can be reduced even for the bearing cooling air. The effect of reducing noise and fan power can be obtained.

In FIG. 13, the throttle mechanism 5 is attached to the exhaust side of the bearing cooling air, but as a modification, the same effect can be obtained even if the throttle mechanism 5 is attached to the intake side as shown in FIG.
According to this embodiment, with respect to the bearing cooling air, it is possible to reduce the air volume of the excessive cooling air and reduce the fan power and the fan noise.

15 and 16 are examples in which the bimetal material 54 is used for the drawing mechanism 5. The bimetal material is a material in which two types of metals having different coefficients of thermal expansion are joined and deformed by a temperature change by utilizing the difference in the coefficient of thermal expansion.

FIG. 15 shows an example in which the throttle mechanism 5 made of the bimetal material 54 is installed in the ventilation passage. When the temperature of the cooling air rises, the bimetal material 54 bends as the temperature rises, as shown in FIG. As a result, the ventilation cross-sectional area is widened, and the same effect as that of the throttle mechanism 5 shown in the first embodiment can be obtained. The drawing mechanism using the bimetal material 54 shown in the present embodiment is the ventilation path 301 between the frame 4 of the first embodiment and the stator core 20, the ventilation path 302 of the rotor core 30 of the second embodiment, or the implementation. The same effect can be obtained regardless of which of the ventilation passages 303 for the bearing cooling air of Example 3 is installed.

In the drawing mechanism 5, a flow path partition plate moved by a shape memory alloy spring was used in Example 1, a flow path partition plate moved by centrifugal force was used in Example 2, and a bimetal material was used in Example 4. The throttle mechanism 5 may be configured to change the flow path cross-sectional area by a driving means such as an actuator.

17 and 18 are examples in which the rotary electric machine of each of the above embodiments is used as an electric motor for driving a railway vehicle. FIG. 17 is a schematic view of a railroad vehicle 400 in which the rotary electric machine of each of the above embodiments is used as an electric motor for driving a railroad vehicle, as viewed from the side. Further, FIG. 18 is a schematic view showing the arrangement of equipment under the floor of the railway vehicle. In the railcar shown in this embodiment, the electric power required for driving the vehicle is taken from the overhead wire through the current collector 404 provided on the upper part of the vehicle, and is supplied to the electric motor 1 as the driving power by the power conversion device 403. .. The electric motor 1 is connected to the wheels 402 via the speed reducer 406. In the figure, 401 is a bogie and 405 is an axle.

In the electric motor for driving a railway vehicle, the loss during acceleration / deceleration between the time when the railway vehicle starts and accelerates from the stopped state and the time when the railway vehicle decelerates and stops is large, and the loss during traveling at the cruising speed. Is small.

By using the rotary electric machine of the first embodiment for the electric motor for driving a railroad vehicle, the ventilation cross-sectional area of the air passage becomes wide during acceleration / deceleration when the cooling air temperature rises, and while traveling at a cruising speed where the cooling air temperature is low, , The ventilation cross-sectional area of the air passage becomes smaller. As a result, it is possible to reduce the amount of excess cooling air when traveling at cruising speed, and reduce fan power and fan noise.

Further, by using the rotary electric motor of the second embodiment for the electric motor for driving a railway vehicle, the ventilation cross-sectional area of the air passage becomes wide during acceleration / deceleration when the electric motor rotates at a low speed, and while the electric motor travels at a cruising speed rotating at a high speed. Reduces the ventilation cross-sectional area of the air passage. This also makes it possible to reduce the amount of excess cooling air when traveling at cruising speed, and reduce fan power and fan noise.

1 Rotor 2 Stator 3 Rotor 4 Frame 5 Squeezing mechanism 6 Cooling air 20 Stator core 22 Stator coil 23 Stator coil end 30 Rotor core 32 Rotor bar 33 End ring 34 Retaining ring 35 Fan 36 Shaft 37 Bearing 38 Bearing cooling blade 51 First spring 52 Second spring 53 Flow path drawing plate 54 Bimetal plate 55 High thermal expansion material 56 Low thermal expansion material 301 Air passage between frame and stator core 302 Rotor core Air passage 303 Bearing cooling air air passage 400 Railroad vehicle 401 Carriage 402 Wheel 403 Power converter 404 Current collector 405 Axle 406 Reducer

Claims (5)

Stator and
Rotors arranged to face each other on the inner diameter side of the stator via a predetermined gap ,
It consists of a fan that rotates integrally with the rotor.
A first flow path in the rotation axis direction provided between the frame for holding the stator and the stator core, and
A second flow path provided through the rotor core in the direction of the rotation axis,
With
By rotating the fan, cooling air is circulated and ventilated inside the electric motor through the first flow path and the second flow path.
In the first flow path or the second flow path , the ventilation cross-sectional area of the flow path is increased during acceleration / deceleration when the cooling air temperature rises, and the ventilation cross-sectional area of the flow path is increased during cruising speed when the cooling air temperature is low. An electric motor for driving a railroad vehicle, which is characterized by having a variable throttle mechanism that makes it smaller . In the electric motor for driving a railway vehicle according to claim 1,
The variable throttle mechanism is composed of a flow path throttle plate and a shape memory alloy that drives the flow path throttle plate, and the temperature of the cooling air flowing through the variable throttle mechanism or the variable throttle mechanism is attached. railway vehicle drive motor, characterized in that the temperature of the motor flow passage aperture plate is driven. In the electric motor for driving a railway vehicle according to claim 1,
The variable throttle mechanism is composed of a bimetal that changes the cross-sectional area of the flow path, and the bimetal changes depending on the temperature of the cooling air flowing through the variable throttle mechanism or the temperature of the electric motor to which the variable throttle mechanism is attached. An electric motor for driving a railway vehicle, which is characterized by being driven. In the electric motor for driving a railway vehicle according to claim 1 ,
The variable drawing mechanism is composed of a flow path drawing plate and an elastic body that presses the flow path drawing plate, and the flow path drawing plate is driven by a centrifugal force generated by the rotation of the rotor. Electric motor for driving railway vehicles . A railway vehicle using the electric vehicle for driving a railway vehicle according to any one of claims 1 to 4.

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