Motor pump

The present invention relates to a motor pump in which a pump and a motor are integrally configured, and more specifically, to a motor pump capable of avoiding troubles at startup due to freezing of the liquid remaining inside.

Conventionally, in a motor pump, if the liquid remaining inside freezes in a low temperature atmosphere such as outdoors, inconveniences such as not being able to start immediately occur. Therefore, in order to avoid such a situation, the liquid remaining inside There is a technology to prevent freezing.

For example, by providing a temperature sensor for measuring the temperature of the liquid remaining inside the canned motor pump and controlling the energization of the stator based on the temperature detected by the temperature sensor, the heat generated by the stator causes the liquid to remain inside the canned motor pump. A technique for preventing freezing of a liquid is known (see, for example, Patent Document 1).<patcit num="1"><text>Japanese Unexamined Patent Publication No. 11-153098</text></patcit>

<p> However, the technique described in Patent Document 1 is inefficient when the non-operating time is long because it is necessary to appropriately energize the stator so that the liquid remaining inside does not fall below the freezing temperature. There was a problem that the power cost was also high. In addition, freezing of the liquid may not be reliably avoided due to a detection error or failure of the sensor that detects the temperature of the liquid.</p><p> Here, a method of thawing the frozen product by energizing the stator even after the liquid is frozen can be considered, but energization (or energization to the extent that the required lift is not reached as disclosed in Patent Document 1 above) is conceivable. If the rotor is energized to the extent that it does not rotate), a sufficient amount of heat is not obtained and it takes a long time to thaw the frozen product.</p><p> The present invention has been made based on such findings, and even in a low temperature atmosphere where the liquid remaining inside the motor pump freezes, the frozen product is thawed in a short time or the liquid is frozen. The main purpose is to provide a motor pump that can be properly started by preventing it.</p>

<p> In order to solve the above problems, as shown in claim 1, the motor pump of the present invention energizes a rotor fixed to a motor rotating shaft, a motor unit provided with a stator that generates a rotating magnetic field of the rotor, and a stator. In a motor pump having a motor drive unit that controls the rotation of the rotor, an impeller driven by the rotation of the motor rotation shaft, and a pump unit having a pump chamber for accommodating the impeller, the rotor rotates in the forward direction. The configuration is provided with a one-way clutch that transmits the driving force from the motor rotating shaft to the impeller only when the motor rotates, and a can that is arranged so as to partition between the rotor and the stator and extends to the pump chamber of the pump section. ..</p><p> According to this, even when the liquid remaining in the pump chamber is frozen in a low temperature atmosphere (that is, the impeller is fixed by a frozen object) when the motor pump is not operating, the motor drive unit causes the motor. By energizing the stator so that the rotating shaft rotates in the opposite direction, the stator and can are heated to thaw the frozen material without transmitting the driving force to the impeller, and the motor pump is started properly. can do. Further, if the stator is energized before the liquid remaining inside is frozen when the motor pump is not operating, the temperature of the liquid remaining in the pump chamber can be maintained above the freezing temperature.</p><p> In addition, when the liquid remaining around the rotor of the motor section freezes in a low temperature atmosphere, the rotor is fixed by the frozen material, so the stator should be energized to the extent that the rotor does not rotate. The stator can be heated to thaw the frozen material around the rotor.</p><p> Here, the liquid remaining in the motor pump is not limited to the liquid transported by the motor pump (for example, water), and may be water contained in the gas in the pump transporting the gas. Further, in order to transfer the heat of the stator and the can to the liquid more efficiently, at least a part of the inner wall of the pump chamber can be formed by the can.</p><p> Further, as shown in claim 2, the motor unit can be configured to have a waterproof structure.</p><p> As a result, since the liquid does not enter the periphery of the rotor fixed to the motor rotation shaft, it is possible to prevent the rotation of the rotor from being hindered by the freezing of the liquid.</p><p> Here, as a waterproof structure of the motor, for example, in the motor portion, the can is formed in a tubular shape having an opening on the pump portion side, and the rotor fixed to the motor rotation shaft is sealed in the opening of the can. A sealing part can be provided.</p><p> Further, as shown in claim 3, when a temperature sensor arranged in the motor unit or the pump unit is further provided, and the motor drive unit detects freezing of the liquid existing in the motor unit or the pump unit from the detection result of the temperature sensor. In addition, the stator can be energized to rotate the rotor in the opposite direction.</p><p> This facilitates the determination of whether or not the liquid is in a frozen state, and when the detection temperature of the temperature sensor is below a predetermined value (predetermined freezing danger temperature of the liquid), it is driven with respect to the impeller. The stator and can can be heated to thaw the frozen material without transmitting force and the motor pump can be started properly.</p><p> In this case, one or more temperature sensors can be arranged at appropriate positions so that the temperature of the liquid existing in the pump chamber of the pump unit or around the rotor of the motor unit can be directly or indirectly detected.</p><p> Further, as shown in claim 4, the motor drive unit is further provided with a lock current detection unit for detecting the restraint state of the motor rotating shaft, and when the lock current detection unit detects the restraint state of the motor rotation shaft, the motor drive unit , The stator can be energized to rotate the rotor in the opposite direction.</p><p> As a result, when the lock current detection unit detects the restrained state of the motor rotating shaft, it is determined that the impeller is in a fixed state by a frozen object, and the driving force is not transmitted to the impeller. The stator and can can be heated to thaw the frozen material, and the motor pump can be started properly.</p><p> As an alternative method, an impeller rotation detection unit that detects the rotation of the impeller is provided in place of the lock current detection unit, and when the impeller rotation detection unit detects the restrained state of the impeller, the motor drive unit may be used. It is also possible to energize the stator to rotate the motor rotation shaft in the opposite direction.</p><p> Further, as shown in claim 5, the rotation of the rotor in the opposite direction can be started by the operation of the operator.</p><p> Further, as shown in claim 6, the motor pump of the present invention has a rotor fixed to a motor rotating shaft and a motor unit provided with a stator that generates a rotating magnetic field of the rotor, and energizes the stator to rotate the rotor. In a motor pump having a motor driving unit to be controlled, an impeller driven by the rotation of the motor rotating shaft, and a pump unit having a pump chamber for accommodating the impeller, the driving force is transmitted from the motor rotating shaft to the impeller. The structure is provided with an intermittent clutch and a heat conductive member arranged so as to partition between the rotor and the stator and extending to the pump chamber of the pump section.</p><p> According to this, even if the liquid remaining in the pump chamber when the motor pump is not operating is frozen in a low temperature atmosphere, the clutch releases the connection between the motor rotating shaft and the impeller, and the motor is driven. By energizing the stator so as to rotate the motor rotation shaft, the stator and can are heated to generate heat without transmitting the driving force to the impeller, and the frozen material is thawed, and the motor pump is properly operated. Can be started. Further, if the stator is energized before the liquid remaining inside freezes when the motor pump is not operating, the liquid temperature can be maintained above the freezing temperature.</p>

<p> As described above, according to the present invention, even in a low temperature atmosphere in which the liquid remaining inside the motor pump freezes, the frozen material is thawed in a short time or the liquid is prevented from freezing to obtain the motor pump. It becomes possible to start up properly.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a schematic configuration of the motor pump of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. This motor pump 1 is used for transporting a fluid (here, water), and has a motor unit 2 for driving a pump and a pump unit 3 arranged in connection with the motor unit 2.

The motor unit 2 is configured as a brushless DC motor, and inside the motor casing 4, a cylindrical rotor 6 fixed to the motor rotating shaft 5a and along the outer peripheral surface thereof to generate a rotating magnetic field of the rotor 6. The stator 7 is provided with a can 8 arranged so as to partition the rotor 6 and the stator 7. The pump unit 3 has a pump chamber 10 provided inside the pump casing 9, and in the pump chamber 10, an impeller 11 fixed to the pump rotation shaft 5b and water existing in the pump chamber 10 A temperature sensor 12 for measuring the temperature of the pump is provided.

Here, one end of the motor rotating shaft 5a is supported by a sealed bearing 13a, and the other end of the impeller 11 via a one-way clutch 14 (a clutch that rotates only in the forward direction and idles in the reverse direction). It is connected to a fixed pump rotating shaft 5b. The pump rotating shaft 5b is supported by two sealed bearings 13b and 13c.

The rotor 6 is provided with a permanent magnet (not shown) on the outer peripheral portion thereof, and the stator 7 is formed from a stator core 15 fixed to the inner peripheral surface of the motor casing 4 and a coil 16 wound around the stator core 15. Become.

The can 8 is made of a thin metal plate, has a bottomed tubular shape having an opening on the pump side in the motor portion 2, and further extends along the inner wall of the pump casing 9 on the pump portion 3 side, and the pump chamber 10 Consists of the inner wall of. As a result, the can 8 functions as a heat conductive member that transfers the heat to the pump chamber 10 side when a part of the can 8 generates heat in the motor unit 2, as will be described later. In addition, the rotor 6 fixed to the motor rotation shaft 5a is sealed by the sealed bearing 13b attached to the opening of the can 8 to prevent liquid leakage from the pump chamber 10 side to the rotor 6 side. .. As a result, the motor portion has a waterproof structure in which water on the pump chamber 10 side does not enter around the rotor 6. The shape and material of the can 8 are not limited to those shown here, and various selections can be made as long as they have at least a function as a heat conductive member for transferring the generated heat to the pump chamber 10 side. Is possible.

The stator 7 is energized by a motor drive driver 20 (motor drive unit) that controls the drive of the motor unit 2, thereby controlling the rotational operation of the rotor 6. When the rotor 6 rotates by energizing the stator 7, an eddy current is generated in the can 8 arranged between the rotor 6 and the stator 7, and an eddy current loss is generated due to the flow path resistance, causing the can 8 to generate heat. To do. The motor drive driver 20 also functions as a device (lock current detection unit) for detecting the lock current generated when the rotor 6 is in the locked state.

Normally, in this type of motor pump, the water to be transported may remain in the pump chamber or the like when the motor pump is not in operation. At this time, if the motor pump is installed in a low temperature atmosphere such as outdoors in a cold region, the water remaining in the pump room freezes, and the impeller is fixed by the frozen material (ice), and the operator Even if you try to start the motor again, you may have trouble starting it properly. However, even in such a state where the residual water is frozen, the motor pump of the present invention having the above configuration can be appropriately started by the following method.

FIG. 3 is a flow chart showing the starting operation of the motor pump of the present invention in a low temperature atmosphere. When starting the motor pump 1, it is first determined whether or not the detected value of the temperature sensor 12 is equal to or lower than the freezing dangerous temperature of water (ST101). When the detected value of the temperature sensor 12 is equal to or higher than the freezing dangerous temperature of water, it is determined that the water is in a liquid state, and normal startup is performed. On the other hand, when the detected value of the temperature sensor 12 is equal to or lower than the freezing danger temperature of water, the motor drive driver 20 energizes the stator 7 to rotate the rotor 6 in the opposite direction (ST102). At this time, the driving force from the motor rotating shaft 5a is cut off by the one-way clutch 14 and is not transmitted to the impeller 11 of the pump unit 3, but the can 8 and the stator 7 generate heat, and the heat is generated by the can 8. It is transmitted to the pump chamber 10 via the above, and raises the temperature of the frozen matter in the pump chamber 10.

Therefore, when the rotor 6 is rotated to a preset time (thaw time of frozen matter) (ST103), the rotation direction of the rotor 6 is switched by the motor drive driver 20 and the rotor 6 rotates in the positive direction (ST104). .. At this time, the driving force from the motor rotating shaft 5a is transmitted to the impeller 11 of the pump unit 3 via the one-way clutch 14. Therefore, the motor drive driver 20 determines whether or not a lock current is flowing (ST105), and when the lock current is detected, the impeller 11 of the pump unit 3 is still fixed by a frozen object. It is determined that there is, and the operations of ST102 to ST104 are repeatedly executed until the lock current is not detected in ST105 (that is, the steady current is flowing). Finally, when it is determined that the impeller 11 of the pump unit 3 is rotating in the positive direction without detecting the lock current in ST105, the starting operation of the motor pump 1 is completed.

The above operation is usually automatically executed, but in some cases, the same operation can be manually executed at the discretion of the operator. For example, when the operator confirms the detected value of the temperature sensor 12 and rotates the rotor 6 in the reverse direction for a certain period of time with a manual switch, the motor pump 1 can be started appropriately.

Although the present invention has been described in detail based on examples, these examples are merely examples, and the present invention is not limited to the examples. It goes without saying that a person skilled in the art can make various modifications or changes without departing from the technical idea of the present invention defined by the claims.

For example, instead of the one-way clutch in the motor pump 1 of the present invention shown in FIGS. 1 and 2, it is possible to provide an electromagnetic clutch and its control device that interrupt the transmission of the driving force from the motor rotating shaft 5a to the impeller 11. Is. Even in this case, when the detection temperature of the temperature sensor 12 is equal to or lower than a predetermined value, the electromagnetic clutch blocks the transmission of the driving force from the motor rotating shaft 5a to the impeller 11, while the motor driving driver 20 cuts off the transmission of the driving force to the stator 11. The rotor 6 can be rotated by energizing 7.

The motor pump of the present invention can be appropriately started by thawing the frozen product in a short time or preventing the liquid from freezing even in a low temperature atmosphere where the liquid remaining inside the motor pump freezes. This is possible, and it is useful as a motor pump that can avoid troubles at startup due to freezing of the liquid remaining in the pump chamber 10.

<figref num="1">Sectional drawing which shows the schematic structure of the motor pump of this invention</figref><figref num="2">II-II sectional view of the motor pump of the present invention shown in FIG.</figref><figref num="3">A flow chart showing the starting operation of the motor pump of the present invention in a low temperature atmosphere.</figref>

Code description

1 Motor pump 2 Motor part 3 Pump part 5a Motor rotating shaft 5b Pump rotating shaft 6 Rotor 7 Stator 11 Impeller 13a, 13b, 13c Sealed bearing 14 One-way clutch 20 Motor drive driver