JPH04127857A - Rotor cooling controller - Google Patents

Abstract

PURPOSE:To control injection volume of cooling medium base on a temperature difference thereof between the injecting part and discharging part by providing a hollow section in a rotor and injecting the cooling medium into the hollow section. CONSTITUTION:A hollow section 22 having an opening A is formed in the center of the rotor 10 of a motor and an injecting/discharging mechanism, comprising a pipe 32 or the like for injecting cooling medium into the hollow section 22, is provided. An injection port temperature measuring element 36 is placed in an injection sump 42 at an injection port 30 in order to measure the temperature of the cooling medium to be injected through the injection port 30 into the injection pipe 32. Similarly, a discharge port temperature measuring element 38 is placed in a discharge sump 44 at a discharge port 34 in order to measure the temperature of the cooling medium to be discharged from a drain tank 28 through the discharge port 34. A control section 46 controls the volume of the cooling medium to be fed to the injection pipe 32 based on the temperature difference. According to the constitution, the rotor is cooled efficiently and availability of cooling medium is enhanced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cooling control device for an electric motor such as an induction motor or a synchronous motor. configured to inject a cooling medium for cooling, and measure the temperature of the cooling medium injection part and discharge part,
The present invention relates to a rotor cooling control device that controls the injection amount of cooling medium based on the temperature difference.

[Prior Art] Various electric motors such as induction motors, rotating armature type synchronous motors, and DC motors are used in various fields. These electric motors generate heat and may require cooling depending on where they are used. For this reason, electric motors equipped with cooling mechanisms have been provided.

For example, as a cooling mechanism for cooling the rotor of an induction motor, a mechanism shown in FIG. 3 is known for boat fishing. That is, in this cooling mechanism, cooling fins 12 are formed on the rotor 10 of the electric motor, and as the rotor 10 rotates, air cooling is performed using the cooling fins 12.

Such a rotor 10 is often manufactured by an aluminum die-casting method, which has the advantage that the cooling fins 12 can be molded at the same time as the rotor.

In this type of induction motor, a cooling mechanism is also known in which an automatic cooling fan 14 is formed on the anti-load side of the rotor 10, as shown in FIG. 4, in order to further increase the cooling efficiency.

This is often used in fully enclosed general-purpose induction motors, and the rotor cooling fins 12 inside the motor frame cool the rotor.
There is an advantage that the heat of the rotor 10 diffused inside the frame can be cooled, and the stator that is in direct contact with the frame can be cooled at the same time.

On the other hand, since the load on the self-excited cooling fan 14 is proportional to the power of the rotation speed, in a vector control type inverter-driven induction motor that is used up to a relatively high rotation speed, self-excited cooling is performed as shown in Fig. 5. Separately excited cooling fan 1 as an alternative to fan 14
An electric motor using 6 is also provided.

[Problems to be Solved by the Invention] However, none of these cooling mechanisms directly cools the rotor, and their cooling efficiency is not necessarily high.

Therefore, as shown in FIG. 6, a plurality of disk-shaped cooling fins 18 are attached to the anti-load side of the rotor 10 in a direction perpendicular to the rotation axis, and a separately excited cooling fan 20 is provided in the diametrical direction. A cooling mechanism configured to perform air cooling using this separately excited cooling fan 20 has been proposed. In addition, the rotor 10 and the cooling fins 18
In order to improve heat transfer, a cooling mechanism has been proposed in which a heat pipe is embedded in the shaft of the rotor 10 in the cooling mechanism shown in FIG.

In this case, compared to the above-mentioned cooling mechanism, since the rotor 10 is cooled quite directly, the cooling efficiency is improved to some extent, but the heat generation source of the rotor 10 and the cooling fin 1
8, and depending on the direction in which the motor itself is mounted, the heat transfer efficiency will be extremely degraded. Therefore, it becomes necessary to increase the diameter or the number of cooling fins 18, but there is a problem in that such a method cannot be adopted in many cases from the viewpoint of miniaturization.

Furthermore, if the cooling fins 18 are not flat, the load on the motor will be large, so the contact time between the cooling medium air and the cooling fins 18 will be shortened, resulting in a problem that the improvement in cooling efficiency will not be that great. It was happening.

For rotary armature type synchronous motors, DC motors, etc., the above-mentioned No. 6
Although a cooling mechanism as shown in the figure has been used, there is a limit to the improvement in cooling efficiency for the same reason as mentioned above.

In other words, if you try to increase the cooling capacity by increasing the size of cooling fins or self-excited cooling fans, the load on the motor will increase, and if the distance between the heat source and the cooling fins is large, the heat transfer efficiency will deteriorate, resulting in an overall However, if the cooling fins have a flat structure to avoid increasing the load on the cooling fins, the contact time between the cooling fins and the cooling medium will be shortened, and the cooling efficiency will not be as high as expected. The problem was that it did not improve.

This is due to the fact that none of these mechanisms directly cools the heat source, and no matter what configuration is adopted, a dramatic improvement in cooling efficiency cannot be expected.

Furthermore, in these rotor cooling mechanisms, no consideration is given to changes in the load on the motor, and the cooling mechanism is normally configured to operate according to the amount of heat generated at maximum load. Even though the efficient use of energy was promoted, the configuration was not satisfactory from the viewpoint of resource and energy conservation.

[Object of the Invention] The present invention has been made to overcome all of the above-mentioned disadvantages, and the load on the motor does not become too large even when the motor is rotated to a high rotation speed, and the heat generation source of the motor is efficiently operated. It is an object of the present invention to provide a rotor cooling control device that can cool the rotor, improve the efficiency of the cooling mechanism as a whole, and promote resource and energy conservation.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a rotor cooling control device for controlling a mechanism for cooling the rotor of an electric motor, the rotor cooling control device including: A hollow part is formed in which an axial end of the rotor is opened, and an injection/discharge mechanism for injecting a cooling medium into the hollow part and discharging the cooling medium is connected to the open end of the hollow part. The apparatus is characterized in that it further includes a control section that measures the temperatures of the cooling medium injection part and the cooling medium discharge part and controls the injection amount of the cooling medium based on the temperature difference.

[Function] The rotor cooling control device according to the present invention is configured such that a hollow portion is provided in the center of the rotor, a cooling medium is injected into the hollow portion, and the temperature of the cooling medium injection portion and discharge portion is adjusted. and controls the injection amount of the cooling medium based on the temperature difference, and controls the injection amount of the cooling medium by a variable valve provided in the injection part, or The injection amount of the cooling medium is controlled by a variable pump provided at the supply source.

[Embodiments] Next, preferred embodiments of the rotor cooling control device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration of a rotor cooling control device according to this embodiment, and FIG. 2 is a detailed diagram of main parts.

The rotor cooling control device includes a hollow portion 22 having an opening A formed in the center of a rotor 10 of an electric motor, and an injection/discharge mechanism comprising an injection pipe 32 and the like for injecting a cooling medium into the hollow portion 22. is provided.

A disk 26 is provided at the periphery of the opening A, and
A drain tank 28 is connected. The disk 26 and the drain tank 28 are mechanisms for collecting the cooling medium discharged from the hollow portion 22 without scattering it and discharging it from the discharge port 34.

In the injection volume 42 near the injection port 30, there is an injection port temperature measuring element 3.
6 is provided, by which the temperature of the cooling medium injected from the inlet 30 into the injection pipe 32 is measured. Also,
In the discharge reservoir 44 near the discharge port 34, there is a discharge port temperature measuring element 38.
is provided, whereby the temperature of the cooling medium discharged from the outlet 34 via the drain tank 28 is measured.

A variable valve 40 is provided between the inlet thermometer 36 and the injection pipe 32 and is configured to control the amount of cooling medium injected into the injection pipe 32. That is, the variable valve 40 is controlled by the control unit 46 based on the temperature difference between the coolant detected by the inlet temperature sensor 36 and the outlet temperature sensor 38, and the amount of coolant corresponding to the temperature difference is supplied to the injection pipe. 32.

The cooling medium discharged from the discharge port 34 is guided to a well-known waste heat treatment means (not shown), subjected to waste heat treatment, and then guided to the circulation mechanism 31 where it is circulated to the injection port 30 again.

The rotor cooling control device according to this embodiment is basically configured as described above, and its operation and effects will be explained next.

Now, when the electric motor rotates and a load is applied, the rotor 10 generates heat in accordance with the load.

At this time, according to the rotor cooling control device according to this embodiment,
The cooling medium is injected from the injection port 30 through the injection pipe 32 into the closed end of the hollow section 22 of the rotor 10, flows inside the hollow section 22 from the closed end of the hollow section 22 toward the opening A, and flows into the drain tank 28. It is discharged. Therefore, the heat generated by the rotor 10 is removed by the cooling medium passing through the hollow portion 22, and the rotor 10 is cooled.

At this time, since the rotor 10 is rotating, the cooling medium is
The hollow part 2 of the rotor 10, which is a relatively long developed heating body, does not simply flow out from the opening A of the hollow part 22.
2, the cooling efficiency is higher than that of conventional cooling mechanisms.

In this manner, the rotor cooling control device has a structure in which the heating element is directly cooled in the vicinity of the heat generation source, so that the cooling efficiency is extremely high.

The temperature of the cooling medium injected into the injection pipe 32 from the injection port 30 is measured by an injection port temperature sensor 36 provided at the injection volume 42 near the injection port 30, and the temperature of the cooling medium discharged into the discharge port 34 is measured by The temperature is measured by an outlet temperature measuring element 38 provided near the outlet 34.

The temperature of the cooling medium measured by the inlet temperature measuring element 36 and the outlet temperature measuring element 38 is sent to the control unit 46 and
The difference between the temperature of the cooling medium at the outlet 34 and the temperature of the cooling medium at the outlet 34 is calculated.

Based on this temperature difference, the control section 46 controls the opening/closing degree of the variable valve 40 provided between the inlet temperature measuring element 36 and the injection pipe 32.

That is, the opening/closing range of the variable valve 40 is defined by the maximum/minimum rotor heat generation of the applied electric motor, and the degree of opening/closing is determined by the coolant outlet temperature (high to low) and (open to closed). , and the cooling medium inlet temperature is (high to
When the temperature difference between the inlet temperature and the outlet temperature is (large to small), it becomes (open-closed).

As described above, according to the present invention, the load condition of the electric motor is indirectly monitored based on the coolant inlet and outlet temperatures, and the coolant injection amount is determined according to the load condition and the coolant condition. Therefore, when the load is small, there is no need to inject a large amount of cooling medium, and when the load is large, a correspondingly large amount of cooling medium can be injected, resulting in efficient rotor cooling as a whole. possible and resource saving.
Cooling that meets the demands for energy conservation can be performed.

Here, in the case of an electric motor such as a servo motor that is used in a wide range of rotation speeds, low speed, high torque, or servo lock, the structure of the hollow part 22 of the rotor 1G is not a simple cylindrical structure, For example, by adopting a structure in which the inner surface of the hollow portion 22 has a truncated conical projection, the cooling medium comes into contact with the inner surface of the hollow portion 22 of the rotor 10, which is a long developed heating body, thereby improving cooling efficiency. can be increased.

If the electric motor is used for the purpose of positioning multiple points within one revolution, the hollow part 22 should have a structure with a spiral wall on the inner surface. By configuring the inner surface of the portion 22 to be tapered, it is possible to obtain the same effect as described above.

In addition, since the coolant passes through the vicinity of the rotation center of the rotor 10, the rotor 10
The rotation loss is extremely small, and the disk 26 for collecting the cooling medium discharged from the hollow part 22 without scattering is also a single thin plate. Rotation loss hardly increases.

In addition, improvements to the hollow structure, such as the height, diameter, and number of truncated conical protrusions, and the height and spiral direction of the spiral wall, can cause heat transfer to deteriorate depending on the installation direction of the motor itself.
That is, deterioration in cooling efficiency can be reduced.

In the embodiment shown in FIGS. 1 and 2, the cooling medium is injected into the hollow part 22 from the tip of the injection pipe 32, but a hole is made in the middle of the injection pipe 32, and the hollow part is also injected from that part. By having a configuration in which the cooling medium flows through the section 22, it is possible to enhance the cooling effect, and by providing a plurality of injection pipes of different lengths and injecting the cooling medium from each, the same effect can be achieved. It is also possible to have one.

As described above, the cooling medium that has absorbed heat through the hollow part 22 of the rotor 10 is collected in the drain tank 28 from the opening A and is discharged from the discharge port 34. The cooling medium discharged from the discharge port 34 is guided to the circulation mechanism 31, subjected to exhaust heat treatment by the exhaust heat treatment means, and then circulated to the injection port 30.

At this time, it is easiest and cheapest to use water as the cooling medium. Furthermore, if there is appropriate water supply and drainage equipment near the installed electric motor, it is also possible to omit the well-known exhaust heat treatment means, circulation mechanism 31, etc., which are not shown.

In cold regions, antifreeze, cooling oil, etc. can be used as a cooling medium instead of water. in this case,
A radiator or the like is generally used as a well-known waste heat treatment means (not shown), and the circulation mechanism 31 is generally composed of a circulation pump, a reserve tank, a filter, etc.

Furthermore, if the cleanliness of the device is required, similar cooling can be achieved using clean air as the cooling medium.

Further, by providing a variable valve 40 and an injection part 42 in the drain tank 28 and using a shape memory alloy as a temperature measuring element, deformation of the shape memory alloy due to temperature change is connected to the variable valve 40 via a link mechanism. By doing so, it is also possible to mechanically control the opening and closing of the variable valve 40.

In addition, by estimating the load on the motor using the early load output of the motor controller or the output of a torque reference, etc., and controlling the opening/closing degree of the variable valve accordingly, it is possible to obtain the same effect as control based on temperature difference. .

[Effects of the Invention] As described above, according to the present invention, a hollow portion is provided in the rotor, an injection/discharge mechanism is connected to the hollow portion, and a cooling medium is injected from the injection/discharge mechanism into the hollow portion of the rotor. Configure it like this,
The temperature of the cooling medium injection part and the discharge part is measured, and the injection amount of the cooling medium is controlled based on the temperature difference, and the cooling medium is controlled by a variable valve provided in the injection part. The injection amount of the cooling medium is controlled, or the injection amount of the cooling medium is controlled by a variable pump provided at the supply source of the cooling medium.

Therefore, there is no need to provide cooling fins or a self-excited cooling fan, and the parts close to the heat generation source can be directly cooled with the cooling medium. Since the amount of cooling medium corresponding to this is supplied, cooling control that meets the requirements for overall efficiency, resource saving, and energy saving can be performed.

Furthermore, in the rotor cooling control device according to the present invention,
The injected cooling medium can be either a liquid or a gas, and this cooling medium is discharged from the opening end of the hollow part of the rotor, and after recovering and heat exhausting the discharged cooling medium, Since the cooling medium is configured to be circulated through the injection/discharge mechanism, it is possible to efficiently reuse the cooling medium.

When water, air, etc. are used as the cooling medium, and there is appropriate supply and exhaust equipment near the installed electric motor, it is also possible to omit the exhaust heat treatment mechanism, circulation mechanism, etc.

Further, in the rotor cooling control device according to the present invention, a convex structure such as a truncated conical projection or a spiral wall is formed on the inner surface of the hollow portion provided in the rotor, or By making the inner surface of the hollow part tapered,
Since the contact time between the cooling medium and the hollow portion can be extended, there is an advantage that the cooling efficiency can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a schematic configuration of a rotor cooling control device according to the present invention, FIG. 2 is a diagram showing a detailed configuration of the rotor cooling control device of FIG. 1, and FIGS. 3 to 6 are conventional diagrams. FIG. 3 is a diagram showing the configuration of a rotor cooling control device in the electric motor. 10...Rotor 22...Hollow part 26...Disk 28...Drain tank 30...Inlet port 31...Circulation mechanism 32...Injection pipe 34...Outlet port 36... ... Inlet thermometer 38 ... Outlet temperature sensor 40 ... Variable valve 42 ... Injection reservoir 44 ... Discharge section 46 ... Control section

Claims (8)

[Claims] (1) A rotor cooling control device for controlling a mechanism for cooling a rotor of an electric motor, in which a hollow portion is formed in the center of the rotor from which an axial end portion of the rotor is opened;
An injection/discharge mechanism is connected to the open end of the hollow part for injecting a cooling medium into the hollow part and discharging the cooling medium, and further measuring the temperature of the cooling medium injection part and discharge part, A rotor cooling control device comprising a control section that controls the amount of coolant to be injected based on the temperature difference. (2) The rotor cooling control device according to claim 1, wherein the control section controls the injection amount of the cooling medium by a variable valve provided in the injection section. (3) The rotor cooling control device according to claim 1, wherein the control unit controls the injection amount of the coolant by a variable pump provided at a supply source of the coolant. . (4) In the rotor cooling control device according to any one of claims 1 to 3, the discharged cooling medium is recovered and subjected to exhaust heat treatment, and then the cooling medium is injected into the hollow part through the injection mechanism. A rotor cooling control device characterized by having a circulation mechanism for. (5) The rotor cooling control device according to claim 4, wherein the injection amount of the cooling medium is controlled by a variable circulation pump provided in the circulation mechanism. (6) In the rotor cooling control device according to any one of claims 1 to 5, the control unit includes an injection part in the injection part and the discharge part in order to measure the temperature of the cooling medium injection part and the discharge part. A rotor cooling control device comprising a temperature measuring element and a discharge temperature measuring element. (7) In the rotor cooling control device according to any one of claims 1 to 5, the control unit includes a shape memory in the injection part and the discharge part in order to measure the temperature of the cooling medium injection part and the discharge part. A rotor cooling control device comprising an injection part temperature measuring element and a discharge part temperature measuring element made of an alloy. (8) In the rotor cooling control device according to any one of claims 1 to 5, the control unit may control the load factor meter output and the torque of the motor controller as a substitute for the temperature difference between the cooling medium injection part and the cooling medium discharge part. A rotor cooling control device characterized by using a reference.