JPH07250454A - Rotating electric machine - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a rotating electric machine that can be operated in a state where vibration and noise are small by controlling the temperature inside the rotating electric machine. [Structure] A fan guide 8 that changes its shape in accordance with a change in temperature inside the electric motor is installed so as to contact the end bracket 3 of the drip-proof protection induction motor 1. The fan guide 8 has a shape that closes the ventilation port 9 when the temperature inside the motor 1 is low, but when the temperature inside the machine exceeds a certain value, it opens the ventilation port 9 and guides cooling air to the fan 6. Become. According to the present invention, the temperature inside the machine rises in a short time after starting the electric motor. As the temperature rises, the damping performance of the varnish that hardens the coil is improved, and the gap between the fitting parts is also reduced.
Vibration and noise at startup can be reduced in a short time. Furthermore, after the internal temperature rises, cooling is performed and the internal temperature is kept constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reducing vibration and noise of a rotary electric machine, and more particularly, a generator and a motor.
The present invention relates to a device capable of reducing electromagnetic vibration and fan noise of a rotating machine such as a computer.

[0002]

2. Description of the Related Art A cooling structure and a cooling control for a rotary electric machine such as a rotary electric motor, a generator and a synchronous machine are very important techniques from the viewpoints of efficient driving of the rotary electric machine and prevention of thermal destruction. Regarding the cooling method and the fin shape, various methods have been proposed up to now (for example, Japanese Patent Laid-Open No. 2-136).
050 publication).

In particular, the cooling performance of an induction motor driven by an inverter at low speeds decreases depending on the rotation speed of the motor, so that the internal temperature of the motor rises abnormally and thermal destruction is large. It's a problem. As a solution to these problems, as described in Japanese Patent Application Laid-Open No. 1-231637, a dedicated motor for driving a fan is used, and the rotation speed of the fan driving motor is changed according to the temperature condition of the main motor. Control and maintain cooling performance.

[0004]

In the above prior art, a cooling structure and a cooling control for suppressing the temperature rise inside the motor as much as possible are performed. In particular, in a rotary electric machine that has a cooling mechanism in which a fan and a rotor are directly connected, even when the temperature inside the rotary electric machine is low, cooling is performed to cool the rotary electric machine even when a certain amount of time has passed and the temperature inside the motor rises. The structure is such that the air volume generated from the fan does not change.

In the above prior art, vibration and noise are generated until the rotating electric machine is driven for a certain period of time and the internal temperature rises to some extent. In particular, when the rotating electric machine is started, its vibration and noise are large, which is a serious environmental problem.

The object of the present invention was made based on the above matters, and a rotating electric machine having a vibration noise reduction device capable of reducing vibration and noise at the time of starting the rotating electric machine for a short time or from the time of starting. Is provided. .

[0007]

According to the present invention, there is provided a fan guide which changes its shape according to a temperature change in a rotary electric machine and limits a flow rate of cooling air passing through a ventilation port of an end bracket. Further, according to the present invention, it is realized by an on-off valve that changes a shape according to a temperature change in a rotating electric machine and limits a flow rate of cooling air passing through a ventilation port of a stator frame.

Further, according to the present invention, it is realized by connecting and disconnecting the cooling fan and the rotor shaft by a clutch mechanism which is connected according to a temperature change in the rotary electric machine.

[0009]

When the internal temperature of the rotary electric machine is low, the fan guide in the rotary electric machine is deformed into a shape that prevents the vent holes of the end brackets. For this reason, the cooling air does not flow into the rotating electric machine, so the temperature inside the machine rises in a short time, the damping performance of the varnish that solidifies the coils in the rotating electric machine is improved, and the looseness of the fitting part is also increased by thermal expansion. Will be alleviated. For this reason,
The vibration and noise level of the rotating electric machine also decreases in a short time. When the internal temperature reaches a certain level, the fan guide transforms into a shape that sends cooling air into the rotating electric machine, so cooling air flows into the rotating electric machine and the efficiency of the rotating electric machine decreases due to excessive temperature rise. And thermal destruction can be prevented.

In the case of an on-off valve whose shape changes according to the temperature change in the rotating electric machine, and also in the case of a clutch mechanism connected by the temperature change in the rotating electric machine, the temperature inside the rotating electric machine is the same as that described for the fan guide. By adjusting the amount of cooling air according to the above, it is possible to prevent the efficiency of the rotating electric machine from being lowered and the thermal destruction due to the excessive temperature rise.

[0011]

1 is a cross-sectional view of a drip-proof protection type induction motor equipped with an embodiment of the apparatus of the present invention. In FIG. 1, a drip-proof protection type induction motor 1 includes a stator frame 2, an end bracket 3 attached to an end of the stator frame 2,
A rotor 4 arranged in the stator frame, a rotor shaft 5 supporting the rotor, a cooling fan 6 attached to the rotor 4, a stator 7 provided on the inner surface of the stator, and an end bracket. 3, a fan guide 8 provided on the inner surface of 3, a ventilation port 9 provided on the end bracket 3, a ventilation port 10 provided on the stator frame 2, a support leg 11 for supporting the stator frame, and an end portion of the stator 7. It is constituted by the end coil 7A. The above-mentioned fan guide 8 is provided so as to be located at the above-mentioned ventilation port 9, and has a shape depending on the temperature, such as a shape memory alloy, a bimorph or a bimetal thermal deformation plate (hereinafter, the term bimorph is often used). It is made of materials that change. Further, the cross-sectional shape of the fan guide 8 has a curved shape as shown in FIG. 2, and the three-dimensional shape of the fan guide has a substantially trumpet shape formed by rotating the curved line around the axis of the rotor shaft. In order to facilitate the opening / closing movement as shown in FIGS. 2 to 3, slits in the radial direction are provided as needed.

As shown in FIG. 2, before the induction motor 1 is started, the fan guide 8 closes the ventilation port 9 of the end bracket 3 or is close to the end bracket, and the ventilation port 9 is provided.
The amount of ventilation that passes through is reduced. Therefore, the induction motor 1
The cooling air does not flow into the inside of the or is a small amount. When the induction motor 1 is started in this state, the temperature inside the electric motor rises in a short time because the cooling performance is lowered.
This temperature rise improves the damping performance of the varnish that hardens the coil, and reduces the gaps between the stator and the stator frame, the end brackets and the stator frame, and the rotor shaft and the fitting portions such as the bearings in the induction motor 1. This reduces vibration and noise. After the operation is continued for a certain period of time, the temperature inside the machine rises, so that the fan guide 8 is deformed so that the ventilation port 9 is sufficiently opened, as shown in FIG. As a result, the cooling air is guided into the induction motor 1 by the fan guide 8 and the fan 6, and the end coil 12
Ventilation port 1 attached to the stator frame 2 by cooling the
It is discharged from 0 to the outside. According to the above-described embodiment of the present invention, as shown in FIG. 4, as compared with the conventional time-noise characteristic curve A, as shown by the characteristic curve B, the convergence time of noise and vibration from the start can be significantly reduced. You can Further, since the normal cooling operation is performed after the temperature rises, it is possible to prevent the efficiency of the induction motor 1 from decreasing and thermal destruction.

FIG. 5 shows another embodiment of the present invention. In this figure, the same parts as those in FIG. 1 are the same parts. In this embodiment, the stator frame 2 is used instead of the fan guide 8 which is deformed according to the change of the temperature inside the machine in FIG.
The ventilation port 10 is provided with an on-off valve 12 that is deformed by a temperature change made of bimorph or shape memory alloy. One end of the on-off valve 12 is supported by the stator frame, moves as shown by an arrow, and rotates in the direction of opening and closing the ventilation port 10.
Reference numeral 13 indicates the flow direction of the cooling air.

When the induction motor 1 is started, the on-off valve 12 closes the ventilation port 10 or approaches the stator frame to reduce the ventilation volume passing through the ventilation port 10. Therefore, the internal temperature of the induction motor 1 rapidly rises, and as in the above-described embodiment, the damping performance of the induction motor 1 is improved and the clearance of the fitting portion is reduced in a short time, and the vibration and noise are reduced. . As the temperature inside the machine rises, the opening / closing valve 12 increases the opening of the ventilation port 10, and the inside of the induction motor 1 is cooled by the cooling air as in the above-described embodiment.

With the above operation, the same effect as that of the above-mentioned device in which the ventilation port 9 of the end bracket 2 is opened and closed by the fan guide 8 can be obtained.

FIG. 6 shows an embodiment for a fully closed induction motor. The fully closed induction motor 14 has the same basic configuration of the stator 7, the rotor 4 and the end bracket 3 as the drip-proof protection induction motor 1 shown in FIG. A big difference is that since the outside air cannot be directly taken into the inside of the electric motor 14, the external fan 6 connected to the rotor shaft 5 and the cooling air generated by the fan are directed to the outside of the stator frame 17. It has a fan guide 15 for guiding. Further, the stator frame 17 is provided with cooling fins 17A. A clutch mechanism 16 is provided between the cooling fan 6 and the rotor shaft 5 to connect them by increasing the temperature inside the machine.
(A specific example will be described later) is provided. 18 is low
The flow direction of heat generated from the heater 4 is shown.

Next, the operation of the above-described embodiment of the apparatus of the present invention will be described. Immediately after starting the induction motor 14, the clutch mechanism 16 does not connect the rotor shaft 5 and the cooling fan 6 because the temperature inside the machine does not rise. Therefore, the temperature inside the machine rises rapidly, and the vibration and noise are reduced in a short time due to the improvement of the damping characteristic of the varnish and the reduction of the fitting portion clearance. When the temperature inside the machine rises, the heat of the rotor 4 is transmitted in the direction indicated by 18, and the clutch mechanism 16 operates to connect the rotor shaft 5 and the cooling fan 6. Cooling air is generated with the rotation of the cooling fan 6, and cools the surface of the stator frame 17 with fins. This suppresses the rise in the temperature inside the machine.

The effects of the present invention described above will be described with reference to FIG. E is a time change of electromagnetic noise, G is a time change of fluid noise due to cooling air, and F is a curve showing a time change of total noise level. The electromagnetic vibration level E converges rapidly due to the improvement of the varnish damping characteristics and the reduction of the fitting portion clearance as the temperature inside the machine rapidly increases. Further, at the time of starting when the electromagnetic noise is large, the fan is not driven and there is no fluid noise G due to the cooling air. Therefore, the total noise level F is the same as the electromagnetic vibration level E. As the temperature inside the machine rises, the clutch mechanism 16 is connected and the fan 6 is driven to generate the fluid noise G. However, at the time when the clutch mechanism 16 is engaged, the level of the electromagnetic vibration E is sufficiently reduced, so that the vibration noise level does not become a problem.

8 and 9, the rotor shaft 5 and the cooling fan 6 are accompanied by the heat inflow from the rotor shown in the above embodiment.
2 shows two embodiments of the clutch 16 for connecting the. An embodiment shown in FIG. 8 is composed of a rotor shaft 5, a bimorph plate member 19 that deforms when a certain temperature or higher is reached, and a friction member 20 such as rubber adhered to the plate member. Instead of the rubber 20, a wear-resistant friction member used for a general clutch can be used. In the embodiment of FIG. 9, instead of the bimorph, a spring 21 made of a shape memory alloy that deforms due to heat change is used.
In these embodiments, the heat 18 in the motor travels through the rotor shaft 5 and heats the rotor end. Then, the outer peripheral portion of the bimorph 19 is curved toward the cooling fan 6, and the spring 21 made of a shape memory alloy or the like is used.
Expands as the temperature rises and is connected to the cooling fan 6 via the rubber 20. As a result, the power of the rotor shaft 5 is transmitted to the cooling fan and cooling air is generated.

By using the above mechanism, the embodiment shown in FIG. 6 can be realized, and since the clutch mechanism has both a temperature sensing function and an actuator function, the temperature sensor can be used in the motor. The number of parts is smaller and the mechanism is simpler than the complicated system configuration in which the temperature is measured, the information is judged by the control device, and the electromagnetic clutch is operated to transmit the power of the rotor shaft 5 to the fan 6. There are advantages.

As a further embodiment, FIG. 10 shows an embodiment of the present invention for an inverter drive system for an induction motor equipped with a cooling air flow rate control device. In this embodiment, an induction motor 22, a temperature sensor 23 for measuring the temperature inside the induction motor 22, a controller 24 for processing signals from the temperature sensor and giving a command to an inverter 25, an induction motor 2
2, an inverter 25 for supplying a current voltage to the fan driving electric motor 26, and a cooling fan 6.

Using the flow chart of FIG. 11, FIG.
An example of the control method of the system will be described. Control device 24
Is given a command to start the induction motor 22. At this time,
From the inverter 25 based on the signal from the controller 24,
A current voltage for driving is supplied to the induction motor 22 (step 110). The temperature information inside the electric motor is constantly monitored by the temperature sensor 23, and the internal temperature is compared with the preset temperature T0 input in advance in the storage device in the control device 24 to determine the next operation (step 111). . If the in-machine temperature T is equal to or higher than the set temperature, the loop for controlling the fan 6 is entered (step 112). If the temperature is below the set temperature,
The cooling fan 6 for the electric motor is stopped (step 11).
3). When the internal temperature reaches the set temperature T0 or higher, the controller 24 determines the rotation speed of the cooling fan 6 based on the relationship between the set temperature and the internal temperature (step 114). The cooling fan motor 26 is driven by the inverter 25 in accordance with a command from the control device 24 (step 115). The above operation is repeated.

By the above control method, the temperature in the electric motor can be rapidly raised to a state where vibration and noise are low because the vibration damping property of the varnish is good and the rattling of the fitting portion is small. Further, as the temperature rises, the fan 6 is driven to generate cooling air, so that it is possible to manage the temperature thereafter. Further, since the fan 6 is not connected to the induction motor 22 by the shaft 5, it is possible to stop the fan 6 when the electric motor internal temperature T is lower than the set value T0. For this reason, at the time of starting, when the internal temperature is low and the vibration noise level due to the electromagnetic excitation force is high, the fluid noise due to the fan drive does not occur, and it is possible to drive the motor silently.

Next, an embodiment in which another control method is applied to the system of FIG. 10 will be shown. The induction motor 22 in the system configuration of FIG.
It is driven by a three-phase AC voltage with a phase difference of 20 degrees or a pulse waveform voltage. By changing the command generated from the control unit 24, the phases of the three phases U, V, W and three phases generated from the inverter 25 can be changed.

FIG. 12 shows the operation of the embodiment using the flow chart. An operation start command is given to the control device 24 of FIG. 10 (step 120). Based on the information of the temperature sensor 23, the control device 24 determines whether the in-machine temperature T is higher or lower than the preset temperature T01 input in advance in the storage area of the control device 24, and determines the next operation. (Step 121). When the temperature inside the machine is lower than the set value T01, as shown in FIG. 13, all three phases of U, V, and W give the same driving voltage and current to the induction motor 22 from the inverter 25 (step 122). In this state, no traveling magnetic field is generated in the stator of the induction motor 22. Therefore, the electric motor 22 does not rotate, and the temperature inside the electric motor only rises. When the in-machine temperature T becomes equal to or higher than the set temperature T01 at which vibration noise due to the electromagnetic excitation force is hard to be generated, as shown in FIG. 13, U, V, W phases 3 phases 120 degrees out of phase Is given from the inverter 25 to the induction motor 22 (step 123). At this time, the induction motor 22
Since a traveling magnetic field is generated in the stator, the rotor rotates. The control method thereafter is the same as that shown in FIG. 11 (steps 124 to 128).

The induction motor 22 is controlled by the above control method.
By heating the rotor before it is rotated, the damping characteristic of the varnish of the coil is improved, and a quiet start can be performed in a state where the clearance between the fitting portions is reduced. Also, after starting,
Since the same control as that of FIG. 11 is performed, the same effect as that of the embodiment of FIG. 11 can be expected.

Although the respective embodiments of the present invention have been described with reference to the example of the induction motor, the present invention is not limited to this, and the present invention can be implemented in electric motors other than induction motors, synchronous machines, generators and the like. Of course, the description of the embodiment will be omitted because it is similar to the above.

[0028]

As described above, according to the present invention,
It is possible to reduce vibration and noise generated when the temperature inside the rotating electric machine is low, for a short time or from the time of starting.

Further, in the embodiment having the function of stopping the cooling fan, it is possible to save power consumption and reduce fluid noise.

[Brief description of drawings]

1 is a side view showing a partial cross-sectional view of a drip-proof protection type induction motor equipped with an embodiment of the present invention.

FIG. 2 is a side view showing a state when the fan guide shown in FIG. 1 is started.

FIG. 3 is a side view showing a normal state of the fan guide shown in FIG.

FIG. 4 is a diagram showing a noise reduction effect of the embodiment of FIG.

5 is a front view showing a partial cross-sectional view of an embodiment in which a flow rate control valve for cooling air is attached to a stator frame ventilation port of the apparatus shown in FIG.

FIG. 6 is a side view showing, in a partial cross-sectional view, a fully-closed induction motor equipped with an embodiment of the present invention.

FIG. 7 is a diagram showing a noise reduction effect of the embodiment of FIG.

8 is a side view showing an embodiment in which a bimorph is used for the clutch shown in FIG.

9 is a side view showing an embodiment in which a spring made of a shape memory alloy is used in the clutch shown in FIG.

FIG. 10 is a configuration diagram of an induction motor drive system by an inverter to which an embodiment of the present invention is applied.

11 is a diagram showing an example of a control method of the configuration of the induction motor drive system shown in FIG.

12 is a diagram showing another embodiment of the control method of the induction motor drive system configuration shown in FIG.

13 is a diagram showing a voltage pattern generated from the inverter according to the control method of FIG.

[Explanation of symbols]

1: Drip-proof protection type induction motor, 2: Stator frame, 3: End bracket 4: Rotor, 5: Rotor shaft, 6: Fan, 7: Starter 8: Fan guide (Drip-proof protection type induction motor) (For electric motor) 9: Ventilation port (end bracket) 10: Ventilation port (stator frame), 1
1: Stator support legs, 12: Airflow control valve 13: Cooling air streamline, 14: Fully closed induction motor 15: Fan guide (for fully closed induction motor), 16: Clutch 17: Finned stator frame , 18: Heat flow from the rotor, 19: Bimorph 20: Friction member, 21: Shape memory alloy spring, 22: Inverter driving induction motor, 23: Temperature sensor, 24:
Control device, 25: Inverter 26: Electric motor for driving cooling fan

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motohachiro Tanaka, 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki, Institute of Mechanical Research, Hiritsu Seisakusho Co., Ltd. Hitachi Industrial Products Division

Claims (6)

[Claims] 1. A rotary electric machine having an end bracket having a ventilation port for internal cooling, wherein a fan guide is provided which is made of a material whose shape changes according to the temperature inside the machine and which opens and closes the ventilation port according to the temperature inside the machine. Characteristic rotating electric machine. 2. A rotary electric machine having a stator frame having a ventilation port, wherein the ventilation port is provided with a valve that opens and closes according to a temperature change. 3. A rotating electric machine having a cooling fan and a rotor shaft, wherein a rotating mechanism is provided between the cooling fan and the rotor shaft, the clutch mechanism being connected according to the temperature inside the machine. 4. The rotating electric machine according to claim 3, wherein the clutch mechanism realizes a clutch operation by a shape change of a bimorph, a shape memory alloy or the like due to a temperature rise. 5. A rotary electric machine is driven by generating a drive current voltage from an inverter power supply in accordance with a command from the control device, and temperature information in the rotary electric machine is detected by a temperature sensor in the rotary electric machine. In the rotating electric machine in which the cooling fan is driven by a driving source different from that of the rotating electric machine, the specific temperature information is input to the storage device in the controller, and based on the information. A rotating electric machine characterized by driving a cooling fan so as to perform a cooling operation. 6. The rotary electric machine according to claim 5, further comprising means for starting the rotary electric machine after raising the temperature inside the machine to a specific set temperature before driving the rotary electric machine.