JP2005330970A - Motor drive type fluid machine, and frequency converter used in the same fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid machine, in which effective operation can be performed in accordance with fluid to be sucked without waste, in which further compactness and light weight are achieved, in which various power sources can be applied, in which power consumption is reduced in a case where there is no fluid to be discharged, and in which resistance to overload and constraint is strong to cause less starting failure (less constraint). <P>SOLUTION: This fluid machine, in which fluid to be handled or fluid to be carried exists at an outer circumferential part of a motor stator, is provided with a motor frame 32 enclosing the outer circumferential part of the motor stator 31, a pump part 10 provided at one end of a motor shaft 16, a first cover 3 provided on the other end side of the motor shaft 16 to support a bearing 34, a frequency converter 36 provided on the counter-bearing side of the first cover 3, and a second cover 37 to contain the frequency converter 36 to the first cover 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fluid machine driven by a motor, and more particularly to a fluid machine that sucks a plurality of fluids having different specific gravities according to circumstances and a frequency converter used in the fluid machine.

  Japanese Utility Model Laid-Open Nos. 1-212290, Sho 2-28592, and Japanese Patent Publication No. 7-58078 are known as fluid machines for sucking a plurality of fluids having different specific gravities according to circumstances.

  A common problem with this type of fluid machine is that the fluid to be sucked varies from case to case, so that it is not possible to adopt the optimum operating method for each fluid and consequently various compromises are required. . That is, when the main focus is on sucking a liquid having a high specific gravity, it is necessary to keep the peripheral speed of the impeller low, and as a result, the ability to suck a gas having a low specific gravity is limited. Also, if the focus is on sucking a gas with a small specific gravity, it is necessary to increase the peripheral speed of the impeller, and if a liquid with a large specific gravity is sucked, a serious overload is applied to the motor, which eventually burns the motor. Will result in

  On the other hand, the fluid machine described in Japanese Utility Model Laid-Open Nos. 1-212290 and 2-28592 is used as a relatively small output and portable pump driven by a single-phase AC power source. It was quite heavy and weighed more than 10kg, so it was not convenient to carry.

勿論、モータとポンプを別々に在庫して置き、必要に応じて組み立てる手法は可能であるが、作業の手間が掛かり不便であった。 In addition, pumps described in Japanese Utility Model Laid-Open Nos. 1-212290 and 2-28592 are often stocked by so-called rental companies and leased to users. At this time, the rental company needs to stock a large number of pumps, for example, as shown in the following table according to the power supply situation of the user, which causes a reduction in the operating rate of the pumps.

Of course, a method of stocking the motor and the pump separately and assembling them as necessary is possible, but it is inconvenient because it requires work.

  The pumps described in Japanese Utility Model Laid-Open Nos. 1-212290 and 2-28592 are often used in an unattended site, rather than being used by the user. For this reason, for example, there is no fluid to be discharged (in most cases, water), but it is not known when and how water will come. Will be consumed. In order to solve this, there are cases where a water level detection device or the like is used in combination. However, in the case of a handling liquid containing foreign matter, some malfunctions may occur.

  In addition, when the pump described in Japanese Utility Model Laid-Open No. 1-212290 is operated in the form of being left as described above, the temperature of the priming water rises and self-priming becomes impossible. Is set in the motor so that, for example, the motor is stopped when the expiration temperature exceeds 60 ° C., and is restarted when the temperature drops to 45 ° C. However, this method has a risk of exhaustion of the thermostat contacts.

  The pumps described in Japanese Utility Model Laid-Open Nos. 1-212290 and 2-28592 are often used with an engine generator as a power source, and the engine throttle can be throttled to suppress engine noise at night. is there. At this time, depending on the generator, the generated voltage may drop, and as a result, there are many cases where the motor is in an overload / overcurrent state. There are also cases in which the impeller is restrained by foreign matter biting or the like, resulting in an overcurrent state. In order to prevent motor burnout due to overcurrent, automatic recovery type thermal protectors using bimetal have been used in the past. However, if ON-OFF is frequently repeated, the bimetal contact will be consumed, eventually resulting in the motor In some cases, burnout occurred.

  Furthermore, when a single-phase motor is used, since the starting torque is small, a starting failure may occur due to a slight foreign matter being caught.

  The present invention has been made in view of the above problems, and performs efficient operation without waste according to the fluid to be sucked, is smaller and lighter, easily adapts to various power sources, and there is no fluid to be discharged It is a technical problem to provide a fluid machine that reduces power consumption, is resistant to overload and restraint, and is less prone to start-up failure (hard to restrain).

  Another object of the present invention is to provide a frequency converter necessary and suitable for realizing the fluid machine.

  In a turbo fluid machine, the torque is generally directly proportional to the square of the rotational speed and directly proportional to the first power of the specific gravity of the handled fluid. In addition, it is known that fluid machines having substantially the same performance become smaller by increasing the number of rotations.

  On the other hand, the size of the motor (three-phase induction motor) is determined by the cooling condition and the magnitude of the torque to be generated, and it is known that the torque is substantially proportional to the current value. Therefore, a motor with substantially the same output can be reduced in size within the allowable range of the cooling condition by increasing the rotation speed (in the case of an induction motor, the operating frequency is increased).

  Further, when comparing a single-phase induction motor and a three-phase induction motor (under the same output and the same rotation speed), it is known that the latter is smaller. This is because not only the starting torque generator (centrifugal switch, capacitor, auxiliary winding, etc.) unique to single-phase induction motors is not required in three phases, but the stator winding and stator core can be small. is there.

  Moreover, the current frequency converter has a built-in computer chip for control, and if information is input, it is possible to supply electric power of a frequency (voltage) according to the input to a motor or the like.

  Furthermore, current frequency converters can convert a single phase to three phases. On the other hand, it is known that the starting torque of a single-phase induction motor is smaller than that of a three-phase induction motor. For this reason, in a fluid machine using a single-phase motor, starting failure due to slight foreign matter biting, etc. Was happening frequently.

Under the above background, in order to solve the problem, the present invention uses the means listed below.
(1) A frequency converter is built in the motor that drives the fluid machine.
(2) In order to determine the fluid specific gravity, the frequency converter is provided with means for detecting the output frequency and current value.
(3) The frequency converter is converted into a plurality of drive modes that are composed of the motor rotation speed (output frequency of the frequency converter) and the operation time and stop time by using a ROM (Read Only Memory) or the like Remember me.
(4) Based on the determined specific gravity, the frequency converter is provided with a function for selecting and implementing the optimum one of the stored drive modes.
(5) When sucking a fluid with a small specific gravity, rotate it at a high speed and when sucking a fluid with a large specific gravity, rotate it at a low speed. It can be so.
(6) After sucking a fluid having a small specific gravity for a predetermined time, it is rotated at a low speed or stopped for a predetermined time, thereby reducing power consumption and contributing to energy saving.
(7) The temperature of the motor or frequency converter or the expiratory water temperature in the self-priming pump is detected by a non-contact temperature detection element thermistor, and this detection signal is sent to the frequency converter, so that an abnormal temperature is detected. Stops the motor and automatically returns when the temperature returns to normal.

  The present invention provides a fluid machine that draws a plurality of fluids having different specific gravities (in many cases, air and water) depending on the case, and selects and implements an optimum drive mode according to the difference in the fluid specific gravity. It is what. The drive mode includes, for example, the number of rotations of the motor, the operation time (the time during which the motor continues to rotate), and the stop time. As a result, for example, when sucking in air with a low fluid specific gravity, the suction effect is increased by increasing the number of revolutions, or water that should be inherently sucked (the specific gravity is greater than air) will not wait until The power consumption can be reduced by stopping the operation or reducing the rotational speed. Further, when water to be sucked and discharged comes out, drainage can be completed relatively quickly (before the water overflows around).

  Further, according to the present invention, the specific gravity of the fluid is detected by detecting the consumed torque per rotation speed, in other words, the current value per generated frequency. At this time, it is possible to obtain the same effect as detecting the current by detecting the voltage and power, and it is possible to detect the fluid specific gravity with high accuracy by simultaneously detecting the current value. It is.

  Further, the present invention selects and implements the most effective drive mode according to the fluid to be sucked based on the detected fluid specific gravity. Since the frequency converter incorporates semiconductor elements such as a CPU and a ROM, what kind of drive mode is selected / implemented is a content included in a so-called software area. For example, in the current electric rice cooker, in order to cook rice deliciously, a certain amount of heat is added for a certain period of time, and the certain period of time is the contents of the kind of unevenness. Since each fluid machine has different handling fluids and different capacities, software (programs) to be prepared are various.

  Further, in the case of a self-priming pump or the like, the present invention is driven at a high speed rotation when sucking air having a small specific gravity, and is driven at a low speed rotation when sucking water having a large specific gravity. Configured. Thereby, the self-priming property can be improved, and a large self-priming height and a short self-priming time can be obtained.

  In the self-priming pump, etc., if the air having a small specific gravity is continuously sucked for a long time, the expiration temperature rises and the self-priming action may not be generated at all. However, the number of revolutions is reduced to reduce power consumption and prevent an increase in expiratory water temperature.

  In the present invention, when a fluid having a small specific gravity is sucked, the motor rotates for a predetermined time and then stops for a predetermined time. That is, the pump is stopped in order to obtain the same effect as described above.

  Further, in the case of the self-priming pump as shown in FIG. 1, the present invention may increase the expiratory water temperature when the air inhalation operation takes a long time, and the self-priming action may be lost. When the temperature rises, the above problem is solved by providing a function of stopping the pump and restarting the operation when the temperature returns to normal.

  In addition, the present invention proposes a preferred form when a fluid machine is configured using the above-described invention. That is, the frequency converter is accommodated in a space formed by a first cover that supports one end of the motor shaft and a second cover that is provided on the side opposite to the bearing. Since this type of pump has a structure that can be expected to be cooled by the liquid handled, it can dissipate the heat generated by the frequency converter, which will be described later, very effectively.

In particular, when the first cover and the second cover are formed of an aluminum alloy, not only the cooling effect is great, but also the harmonic noise generated by the frequency converter is cut off and the noise is not affected externally.
The second cover assembly is configured by fixing the frequency converter and the power cable to the second cover, and the second cover assembly and the first cover assembly can be assembled independently, thereby achieving a very effective effect. Can be obtained. That is, if one type of first cover assembly and a plurality of types of second cover assemblies that differ depending on the type of input power supply are prepared, it is possible to cope with a plurality of power sources depending on the combination. Since the first cover assembly including the motor stator is heavy, if different types are stocked, it takes time to manage and move the first cover assembly. According to the present invention, since it is only necessary to attach a plurality of lightweight second cover assemblies to one type of first cover assembly, the productivity in the factory is good.

  The floor residual water drainage pump described in Japanese Utility Model Publication No. Hei 2-28592 enables drainage from a low water level by bringing an impeller close to the floor surface. In this method, air is discharged by the air suction capability of the impeller itself, and then water is discharged. Naturally, the outer diameter of the impeller becomes large.

  Further, the present invention is premised on speeding up, and is characterized in that an initial air suction function is provided to the impeller nut. High-speed rotation (80 Hz) allows air to be quickly discharged by a relatively small outer diameter impeller nut, and then the sucked water is slowly discharged with good pump efficiency by the impeller (rotating at 60 Hz). can do. That is, since the impeller does not require air suction capability, it only needs to have a function and performance for efficiently discharging water. Therefore, it is more efficient than the conventional pump described in Japanese Utility Model Laid-Open No. 2-28592.

  A conventional pump requires a structure that effectively releases the sliding heat of the mechanical seal when rotating at high speed during air suction. Conventionally, the sliding heat is dissipated from the outer surface of the motor frame and the outer surface of the intermediate casing via the lubricating oil of the mechanical seal. The present invention proposes to provide heat dissipation ribs in the intermediate casing to effectively do this. It is known that when the mechanical seal is heated to a high temperature by sliding heat, the rubber surrounding the sliding surface and the sliding member is deteriorated and consumed quickly.

  A frequency converter incorporated in a fluid machine driven by a motor, particularly a frequency converter incorporated in a submersible pump or the like, preferably has a simple structure and a simple function. This eliminates the function of taking control signals from the outside or supplying the signals to the outside, while adding the function to improve or maintain the function of the fluid machine, This is because the productivity can be improved and the productivity of the frequency converter can be improved.

  In addition, the present invention is a frequency converter including only an input unit, an output unit, and a control unit that suppresses overcurrent, and is configured so that fine adjustment of frequency and voltage is impossible in a finished product state. ing. That is, even if an amateur disassembles the fluid machine, the setting or program of the frequency converter cannot be changed, so that it is possible to prevent the fluid machine from causing unnecessary troubles due to incorrect work. This is a very important factor in a fluid machine that is used for rental purposes and is maintained by a rental company.

  Further, by devoting only to simple functions, the frequency converter can be miniaturized and can be easily accommodated in a fluid machine or a motor. At the same time, the productivity can be improved and the cost can be kept low, and it can be easily used as a consumable part similar to a capacitor used in a conventional single-phase induction motor.

  The frequency converter used in the present invention has a plug-in type input terminal in the input section. For example, a fluid machine power cable connected to a household single-phase power outlet is taken into a motor and connected to the plug-in input terminal. When the power source is, for example, a single-phase AC 100V, 50 Hz, the frequency converter converts this into, for example, a three-phase AC 100V, 60 Hz, and is supplied to the three-phase induction motor from the plug-in type output terminal.

  At this time, the output current rating of the frequency converter and the rated current value of the motor are kept the same. If the load current of the motor is lower than the rating (for example, when the fluid specific gravity is small), the voltage remains at 100V. A function for increasing only the frequency is added. However, the upper limit is set to about 80 Hz. Further, when the load current of the motor is higher than the rating (for example, when the fluid specific gravity is large), a function of lowering the output frequency is provided with the voltage / frequency ratio V / F kept constant.

  As a result, the fluid machine of the present invention can be controlled. Furthermore, the frequency converter can determine the fluid specific gravity, and can select and implement the drive mode. During this time, it is not necessary to input a special control signal or the like to the frequency converter.

  Further, the conventional frequency converter is assumed to be used in the air, and is relatively weak against the presence of moisture and moisture. On the other hand, the fluid machine (pump) shown in FIG. 1 and the like of the embodiment of the present invention includes a mechanical seal in the shaft seal portion. Since the mechanical seal is a consumable part, it may leak when the usage time is extended. The moisture eventually enters the motor. When the frequency converter is housed in a motor and used, its moisture resistance and water resistance should be at least as high as that of the stator winding of the motor.

  In other words, even if it is unavoidable that the insulation resistance of the terminal portion is lowered due to the presence of moisture, it is necessary not to cause a problem that cannot be repaired. Furthermore, it is desired that the insulation is restored by drying only the terminal portion. Therefore, according to the present invention, built-in components such as a semiconductor device and a capacitor are accommodated in a case, and the case is filled with resin and cured to expose only the input / output terminals to the outside. As a result, like the rectangular parallelepiped capacitor with a resin case conventionally used for a single phase induction motor, it can be used in a motor simply and with high reliability.

  When the frequency converter is accommodated in a fluid machine or a drive motor, it is most important to be small in size. In particular, in the case of a portable pump or the like, if the frequency converter is large, its housing case and cover are also large, resulting in an increase in weight and inconvenience.

  Therefore, in the present invention, a built-in component is packed in a case of an electrical insulator (for example, plastic), and electrical insulation between the components is secured by interposing an insulating film therebetween. Conventional frequency converters have become large because of the need to provide a space (edge distance) for electrical insulation between the substrates and to provide a fixing member for fixing the substrate to the case. In the present invention, since the edge distance is substantially zero and each substrate is fixed by curing the filling resin, an extremely small frequency converter can be configured. This method requires measures for cooling the frequency converter (when a resin case is used) and for shielding harmonic noise. The fluid machine of the present invention solves these problems by configuring the covers for accommodating the frequency converters with an aluminum alloy and so that the handled fluid contacts the cover.

  Further, according to the present invention, in order to ensure safety, in the case of electric leakage, the output of the frequency converter is stopped and the resetting can be performed by turning on / off the power. As a result, it is possible to ensure safety with high reliability without using an extra reset switch.

  In the fluid machine shown in FIG. 1 of the embodiment of the present invention, the expiratory water temperature rises due to a long-time air suction operation, and eventually self-priming becomes impossible. Accordingly, the present invention is configured to provide a contactless element such as a thermistor in the frequency converter so that the fluid machine is stopped when the abnormal temperature rises and the operation is resumed when the temperature returns to the normal temperature. ing. Therefore, unlike a conventional contact type element (bimetal), there is no worry about contact consumption. At the same time, this function can protect the motor and the frequency converter itself from an abnormal temperature rise.

  Conventionally, capacitors used in motors have various dimensions and often have difficulty in securing a mounting space. Therefore, the present invention proposes to standardize the shape dimensions using a standard number in the so-called JIS standard. As a result, it can be conveniently accommodated in the motor. In particular, when L × W × H is 2: 1: 1 or 1.4: 1: 1, it is preferable to accommodate a plurality of L × W × H in the motor.

  According to the present invention, effective operation is performed without waste depending on the fluid to be sucked in, it is more compact and lightweight, easily compatible with various power sources, and reduces power consumption when there is no fluid to be discharged, It is possible to provide a fluid machine that is strong against overload and restraint and is less prone to start-up failure (hard to restrain).

Hereinafter, embodiments of a motor-driven fluid machine according to the present invention and a frequency converter used in the fluid machine will be described.
1 and 2 are views showing a portable motor pump as a first embodiment of a motor-driven fluid machine according to the present invention. FIG. 1 is a longitudinal sectional view of the motor pump, and FIG. 2 is a plan view of the motor pump. It is.

  In FIG. 1, reference numeral 1 is a barrel made of a cylindrical steel plate, and a motor pump main body 2 is housed inside the barrel 1. As shown in FIG. 2, the motor pump main body 2 is arranged eccentrically with respect to the cylindrical barrel 1. The upper opening of the barrel 1 is closed by the first cover 3, and the lower opening of the barrel 1 is closed by the pump base 4. A seal ring 5 made of an elastic material such as rubber is provided between the barrel 1 and the first cover 3. The pump base 4 is composed of a rubber material 7 molded on the upper surface and outer periphery of the bottom plate 6, and the rubber material 7 seals the lower opening of the barrel 1. As a result, the substantially annular space 8 formed between the barrel 1 and the motor pump portion 2 is held in a sealed state.

  The motor pump body 2 includes a lower pump unit 10 and a motor unit 30. The pump unit 10 is interposed between the pump casing 11, the impeller 12 disposed in the pump casing 11, the intermediate casing 13 covering the upper opening of the pump casing 11, and the intermediate casing 13 and the pump casing 11. And a plate 14 made of an elastic material such as rubber. The pump base 4, the pump casing 11 and the plate 14 are fixed to the intermediate casing 13 with bolts 15. The impeller 12 is fixed to the motor shaft 16 by an air lock prevention nut 17. A wide gap is formed in the front surface of the impeller 12, and so-called vortex that reduces the wear of the impeller by discharging foreign matters such as sand together with the vortex generated in the space of the gap during pump operation. Configure the pump.

  A pump chamber suction port 18 is formed in the pump casing 11, and the pump chamber suction port 18 communicates with a pump casing suction port 20 corresponding to a pump part suction port via a suction passage 19. The pump casing suction port 20 is connected to a suction pipe 22 fixed to the first cover 3 via a suction pipe 21.

  In the vicinity of the pump casing suction port 20, a circulating water suction port 23 opened toward the suction passage 19 is formed. A pump chamber discharge port 24 corresponding to the pump unit discharge port opens into the annular space 8, that is, the discharge chamber in the barrel. A discharge pipe 25 is fixed to the first cover 3. A discharge faucet 26 is detachably attached to the discharge pipe 25.

  On the other hand, the motor unit 30 includes a stator 31, a motor frame 32 surrounding the outer periphery of the stator 31, a rotor 33 disposed in the stator 31, and a motor shaft 16 to which the rotor 33 is fixed. It is composed of The motor shaft 16 is supported by upper and lower bearings 34 and 35. The upper bearing 34 is supported by the first cover 3, and the lower bearing 35 is supported by the motor frame 32.

  Further, a frequency converter 36 is disposed on the side opposite to the bearing of the first cover 3, and the frequency converter 36 is hermetically sealed by a second cover 37 fixed to the upper part of the first cover 3. That is, the frequency converter 36 is accommodated by the first cover 3 and the second cover 37. The cable 38 is fixed to the side surface of the second cover 37, and the portable handle 39 is fixed to the upper surface of the second cover 37.

Next, the operation of the motor pump configured as described above will be described.
When the pump faucet 26 is removed at the time of starting the pump and the required self-priming exhalation water is supplied into the barrel 1, the exhalation water enters an annular space (discharge chamber) 8 surrounded by the motor pump body 2 and the barrel 1. Stored. Next, when the pump is started, expiratory water is sucked into the pump casing 11 from the self-priming circulating water suction port 23 opened in the annular space 8. In this process, the liquid sucked from the circulating water suction port 23 for self-priming generates a negative pressure by the ejector action when it is ejected toward the suction passage 19, and the negative pressure is generated to pass through the suction pipe 22. The air in the suction pipe (not shown) connected to the suction pipe 22 is sucked.

  The air on the suction side sucked in as described above and the liquid sucked from the self-priming circulating water suction port 23 become an air-water mixture and is pressurized by the impeller 12 in the pump chamber, and discharged from the pump chamber. The gas is discharged from the outlet 24 into the annular space (discharge chamber) 8. The discharged air / water mixture is separated in the annular space 8, the air is discharged to the outside through the discharge pipe 25, and only the liquid is again sucked in from the self-priming circulation water inlet 23, in this way. Circulating fluid is formed and self-priming action is performed.

  As the air on the suction side is gradually extracted due to the above self-priming action, liquid is sucked from the suction pipe 22 fixed to the first cover 3, merged with the above-described circulation flow in the pump chamber, and pressurized by the impeller 12. And discharged into the annular space 8. In a state where the inside of the annular space 8 is filled with the discharged liquid, the liquid is discharged from the discharge pipe 25 fixed to the first cover 3 and the self-priming action is finished.

  After the self-priming action is thus completed and the operation is shifted to the regular pump operation, the liquid acting as a normal motor pump is pressurized by the impeller 12 through the suction pipe 22 of the first cover 3. Then, the liquid is discharged from a discharge pipe 25 fixed to the first cover 3 to a predetermined place.

Next, an embodiment of the frequency converter used in the pump of FIGS. 1 and 2 will be described with reference to FIG.
FIG. 3 shows an embodiment in which a three-phase alternating current is used as an input. As shown in FIG. 3, the frequency converter 36 includes a rectifier circuit 71 that converts alternating current into direct current, a converter portion that includes a smoothing capacitor 72 that smoothes the rectified voltage, and an inverter unit 73 that converts direct current into alternating current. Consists of. An auxiliary power source 74 and a voltage detector 75 that detects the DC voltage of the converter are connected to the converter that is the DC portion. Further, the auxiliary power supply unit 74 and the voltage detection unit 75 are connected to a control unit 76 that performs driving mode and discrimination, and drives the inverter unit 73 from the control unit 76 by a PWM signal. A current detection sensor 78 is provided on the output side of the three-phase inverter 73, and the detection value of the sensor 78 is converted into a signal by the current detection unit 77 and sent to the control unit 76.

  The motor 30 is connected to the output side of the three-phase inverter 73. A temperature sensor 79 is provided in the motor 30, the motor winding temperature is detected by the sensor 79, and the detection signal is sent to the control unit 76. In the embodiment of the present invention, a rectifier circuit 71 and a smoothing capacitor 72 are provided as a rectifier in the frequency converter 36, which is unrelated to the phase connection of the three-phase AC on the input side, and to the motor 30. Since the electric power is supplied from the inverter unit 73 and is not restricted by the input side connection sequence, the motor 30 can prevent reverse rotation.

  In the embodiment of the present invention, a three-phase PWM signal is output from the control unit 76 and drives the three-phase inverter via the drive circuit. Therefore, when the power is turned on, the rotational speed of the motor 30 is gradually increased, A proportional equivalent sine wave voltage is created and output as a PWM waveform by the control unit 76, so soft start is possible, and by gradually increasing the rotation speed and voltage, an inrush current during acceleration is avoided, Smooth acceleration is possible.

  FIG. 4 shows an embodiment where single-phase alternating current is used as an input. In the embodiment shown in FIG. 3, the three-phase alternating current is converted into direct current by the rectifier circuit 71. However, in the embodiment shown in FIG. 4, the single-phase alternating current is converted into direct current by the rectifier circuit 71. An example of a DC input is shown in FIG. In the embodiment shown in FIG. 5, in the case of direct current, a reverse connection protection diode 83 and a protection diode 84 are added so that the user can protect even if the polarity of the power supply connection is wrong. Of course, protection can be performed with the protection diode 83 alone.

  The embodiment shown in FIGS. 3 to 5 differs only in the input part, but includes a voltage detection unit 75, an auxiliary power supply unit 74, a control unit 76, a three-phase inverter unit 73, a current detection unit 77, a current detection sensor 78, and a temperature sensor 79. Has the same function for three-phase AC, single-phase AC, and DC. In the embodiment shown in FIGS. 3 to 5, reference numeral 2 denotes a motor pump body.

  In the embodiment shown in FIGS. 3 to 5, the voltage detector 75 detects the voltage of the DC portion (rectified), monitors the voltage, and sends a signal to the controller 76. The current detection unit 77 and the current detection sensor 78 monitor the motor load state and protect the motor overload by detecting the current flowing into the motor from the three-phase inverter output. The temperature sensor 79 detects the temperature of the motor and sends a signal to the control unit 76 to stop the output and protect the motor 30 and / or the frequency converter 36 in order to protect at high temperatures.

  In the embodiment shown in FIGS. 3 to 5, the control unit 76 has a control function of stopping the output by a signal from the current detection unit 77 or a signal from the temperature sensor 79. The control unit 76 includes a ROM that stores setting contents such as PWM control signals, drive modes, detection level discrimination criteria, a CPU and a control IC having an arithmetic processing function, and selects a drive mode, high-speed rotation and low-speed rotation. It has processing functions such as determination of self-priming time and control of self-priming time.

  6A and 6B are diagrams showing the structure of the frequency converter according to the present invention, in which FIG. 6A is a sectional view and FIG. 6B is a side view. As shown in FIG. 6A, an insulating film 81 is interposed between the built-in components including the smoothing capacitor 80 and the like, the whole is accommodated in the resin case 82, and the resin material 83 is filled between the components. It has been deceived. The built-in component is fixed by curing the filled resin material 83.

  In the embodiment shown in FIG. 6, the reason why the power unit 85 with heat generation is arranged in the vicinity of the input terminal 86 and the output terminal 87 is that the connection can be shortened. In consideration of cooling of the power unit 85, there may be a method of arranging the power unit 85 on the surface of the hexahedral resin case 82 having the best cooling condition. The resin case 82 has a rectangular parallelepiped shape, and its length × width × height (L × W × H) is standardized using a standard number. That is, for example, L: W is 2: 1 or L: W is 1.4: 1, and W: H is set to 1: 1.

  The present invention includes a pump that sucks a plurality of fluids having different specific gravities (in many cases, air and water) according to the case, and includes a means for determining the fluid specific gravity, and an optimum driving mode according to the difference in fluid specific gravity. A function to be selected and implemented is given. The drive mode includes, for example, the number of rotations of the motor, the operation time (the time during which the motor continues to rotate), and the stop time. As a result, for example, when sucking in air with a low fluid specific gravity, the suction effect is increased by increasing the number of revolutions, or water that should be inherently sucked (the specific gravity is greater than air) will not wait until The power consumption can be reduced by stopping the operation or reducing the rotational speed. Further, when water to be sucked and discharged comes out, drainage can be completed relatively quickly (before the water overflows around).

  The present invention includes a frequency converter 36 for supplying electric power to the motor, and detects the specific gravity of the fluid by detecting the consumed torque per rotation speed, in other words, the current value per generated frequency. It is. At this time, it is possible to obtain the same effect as detecting the current by detecting the voltage and power, and it is possible to detect the fluid specific gravity with high accuracy by simultaneously detecting the current value. It is. Then, based on the detected fluid specific gravity, the most effective drive mode is selected and implemented according to the fluid to be sucked. Since the frequency converter 36 incorporates semiconductor elements such as a CPU and a ROM, what kind of drive mode is selected / implemented is a content included in a so-called software area. Since each pump has a different fluid and its capacity, the software (program) to be prepared varies widely.

  In the present invention, the self-priming pump shown in FIGS. 1 and 2 is driven at a high speed when sucking air with a small specific gravity, and is slow when sucking water with a large specific gravity. It is configured to be driven by rotation. Thereby, the self-priming property can be improved, and a large self-priming height and a short self-priming time can be obtained. In the self-priming pump shown in FIGS. 1 and 2, if the air having a small specific gravity is continuously sucked for a long time, the expiratory temperature rises and the self-priming action may not be generated at all. However, the number of revolutions is reduced to suppress power consumption and prevent an increase in expiratory water temperature.

  In the present invention, in the case of the self-priming pump as shown in FIG. 1 and FIG. 2, if the air suction operation takes a long time, the expiratory water temperature may rise and the self-priming action may be lost. The above problem is solved by providing a function of stopping the pump when the temperature rises and restarting the operation when the temperature returns to normal.

  Moreover, in this invention, the frequency converter 36 is accommodated in the space formed by the 1st cover 3 which supports the end of the motor shaft 16, and the 2nd cover 37 provided in the non-bearing side. Since this type of pump has a structure that can be expected to be cooled by the liquid to be handled, the heat generated by the frequency converter 36 can be dissipated very effectively. In particular, when the first cover 3 and the second cover 37 are formed of an aluminum alloy, not only the cooling effect is large, but also the harmonic noise generated by the frequency converter 36 is cut off and the noise is affected to the outside. There is no.

  Further, a first cover assembly including the first cover 3 and the motor frame 32 is formed, and the frequency converter 36 and the power cable 38 are fixed to the second cover 37 to form a second cover assembly. By enabling the assembly and the first cover assembly to be assembled independently, a very effective effect can be obtained. That is, if one type of first cover assembly and a plurality of types of second cover assemblies that differ depending on the type of input power supply are prepared, it is possible to cope with a plurality of power sources depending on the combination. Since the first cover assembly including the motor stator 31 and the motor frame 32 is heavy, if different types are stocked, it takes time to manage and move the first cover assembly. According to the present invention, since it is only necessary to attach a plurality of lightweight second cover assemblies to one type of first cover assembly, the productivity in the factory is good.

  A frequency converter incorporated in a fluid machine driven by a motor, particularly a frequency converter incorporated in a submersible pump or the like, preferably has a simple structure and a simple function. This eliminates the function of taking control signals from the outside or supplying the signals to the outside, while adding the function to improve or maintain the function of the fluid machine, This is because the productivity can be improved and the productivity of the frequency converter can be improved.

  The present invention is a frequency converter that includes only an input unit, an output unit, and a control unit that suppresses overcurrent, and is configured so that fine adjustment of frequency and voltage is impossible in a finished product. . That is, even if an amateur disassembles the fluid machine, the setting or program of the frequency converter cannot be changed, so that it is possible to prevent the fluid machine from causing unnecessary troubles due to incorrect work. This is a very important factor in a fluid machine that is used for rental purposes and is maintained by a rental company.

  Further, by devoting only to simple functions, the frequency converter can be miniaturized and can be easily accommodated in a fluid machine (pump) or motor. At the same time, the productivity can be improved and the cost can be kept low, and it can be easily used as a consumable part similar to a capacitor used in a conventional single-phase induction motor.

  The frequency converter 36 used in the present invention includes a plug-in type input terminal 86 in the input section. For example, a fluid machine power cable connected to a household single-phase power outlet is taken into the motor and connected to the plug-in type input terminal 86. When the power source is, for example, a single-phase AC 100 V, 50 Hz, the frequency converter 36 converts this into, for example, a three-phase AC 100 V, 60 Hz, and is supplied from the plug-in type output terminal 87 to the three-phase induction motor. .

  At this time, the output current rating of the frequency converter and the rated current value of the motor are kept the same. If the load current of the motor is lower than the rating (for example, when the fluid specific gravity is small), the voltage remains at 100V. A function for increasing only the frequency is added. However, the upper limit is set to about 80 Hz. Further, when the load current of the motor is higher than the rating (for example, when the fluid specific gravity is large), a function of lowering the output frequency is provided with the voltage / frequency ratio V / F kept constant.

  As a result, it is possible to control the motor to rotate at a high speed when sucking a fluid having a small specific gravity and to rotate the motor at a low speed when sucking a fluid having a large specific gravity. Furthermore, the frequency converter can determine the fluid specific gravity, and can select and implement the drive mode. During this time, it is not necessary to input a special control signal or the like to the frequency converter.

  Further, the conventional frequency converter is assumed to be used in the air, and is relatively weak against the presence of moisture and moisture. On the other hand, the fluid machine (pump) shown in FIG. 1 and the like of the embodiment of the present invention includes a mechanical seal 61 in the shaft seal portion. Since the mechanical seal is a consumable part, it may leak when the usage time is extended. The moisture eventually enters the motor. When the frequency converter is housed in a motor and used, its moisture resistance and water resistance should be at least as high as that of the stator winding of the motor.

  In other words, even if it is unavoidable that the insulation resistance of the terminal portion is lowered due to the presence of moisture, it is necessary not to cause a problem that cannot be repaired. Furthermore, it is desired that the insulation is restored by drying only the terminal portion. For this reason, as shown in FIG. 6, the present invention accommodates built-in components such as semiconductor devices and capacitors in a resin case 82, fills the resin case 82 with a resin material 83, and cures the input / output terminals 86, Only 87 is exposed to the outside. As a result, like the rectangular parallelepiped capacitor with a resin case conventionally used for a single phase induction motor, it can be used in a motor simply and with high reliability.

  When the frequency converter is accommodated in a fluid machine or a drive motor, it is most important to be small in size. In particular, in the case of a portable pump or the like, if the frequency converter is large, its housing case and cover are also large, resulting in an increase in weight and inconvenience.

  Therefore, according to the present invention, a built-in component is packed in an electrical insulator (plastic) case 82, and electrical insulation between the components is ensured by interposing an insulating film 81 therebetween. Conventional frequency converters have become large because of the need to provide a space (edge distance) for electrical insulation between the substrates and to provide a fixing member for fixing the substrate to the case. In the present invention, since the edge distance is substantially zero and each substrate is fixed by curing the filling resin, an extremely small frequency converter can be configured. This method requires measures for cooling the frequency converter (when a resin case is used) and for shielding harmonic noise. In the fluid machine (pump) of the present invention, the covers including the first cover 3 and the second cover 37 that house the frequency converter 36 are made of an aluminum alloy, and the handling fluid is in contact with the cover. By doing so, these problems are solved.

  In the present invention, in order to ensure safety, the output of the frequency converter is stopped in the case of a leakage, and the reset can be performed by turning on and off the power. As a result, it is possible to ensure safety with high reliability without using an extra reset switch.

  In the fluid machine (pump) shown in FIG. 1 of the embodiment of the present invention, the expiratory water temperature rises due to the air suction operation for a long time, and eventually self-priming becomes impossible. Therefore, the present invention provides a non-contact element such as a thermistor in the frequency converter to stop the fluid machine (pump) when the abnormal temperature rises, and resume operation when the temperature returns to the normal temperature. It is configured. Therefore, unlike a conventional contact type element (bimetal), there is no worry about contact consumption. At the same time, this function can protect the motor and the frequency converter itself from an abnormal temperature rise.

  Conventionally, capacitors used in motors have various dimensions and often have difficulty in securing a mounting space. The present invention proposes to standardize the shape of the frequency converter using a standard number in the so-called JIS standard. As a result, it can be conveniently accommodated in the motor. In particular, when L × W × H is 2: 1: 1 or 1.4: 1: 1, it is preferable to accommodate a plurality of L × W × H in the motor.

FIG. 7 is a longitudinal sectional view showing a residual water drainage pump which is a second embodiment of the motor driven fluid machine of the present invention.
The configuration of the peripheral members of the motor unit 30 and the frequency converter 36 of the residual water drainage pump of this embodiment is the same as that of the embodiment shown in FIGS.

  An impeller 43 is attached to the lower end of the motor shaft 16 by an impeller nut 44. The pump casing 51 incorporating the impeller 43 is formed of an inexpensive material such as a rubber material without rust, and is attached to the intermediate casing 52 with a bolt 54 via a bottom plate 53. A strainer 55 having a large number of small holes is fixed to the central portion of the bottom plate 53. The impeller 43 is disposed in the pump casing 51 with a slight clearance between the front (front) clearance a, the side (side) clearance b, and the rear (back) clearance c. The pump casing space is configured to be as small as possible.

  A number of strainer / pump legs 57 formed integrally with the casing 51 are formed on the peripheral edge of the bottom surface of the pump casing 51 while maintaining a slight height d such as 1 to 3 mm. A number of inlets (not shown) of residual water are formed between the two, and thereby the suction space is made as small as possible. Accordingly, the distance (interval) f between the impeller 43 and the floor surface is made as short as possible.

  A pump discharge port 59 is provided in the intermediate casing 52 fixed to the rear surface (upper side in the drawing) of the pump casing 51 by a bolt 54. The pump discharge port 59 also serves as the air / water separation chamber 60a. Therefore, a discharge pipe 60 having a large contact area with the outside air is attached. A hose coupling 60b connected to a discharge conduit (not shown) is integrally provided on the upper portion of the discharge pipe 60. In FIG. 7, reference numeral 61 denotes a mechanical seal, and lubricating oil is enclosed around the mechanical seal 61.

  FIG. 8 is a diagram showing details of the impeller nut, FIG. 8A is a side view, and FIG. 8B is a cross-sectional view. The substantially hexagonal impeller nut 44 is formed with a plurality of radial grooves 44a, and these grooves 44a provide the nut with an air suction function. As shown in FIG. 7, the impeller nut 44 protrudes to the floor side from the blade tip of the impeller 43, and the outer diameter of the impeller nut 44 and the clearance e of the pump casing suction port 62 are minimized.

Next, the operation of the residual water drainage pump configured as described above will be described.
Suction formed integrally with the pump casing 51 by generating a negative pressure at the pump casing suction port 62 by the rotation of the impeller 43 when the pump is operated on the floor with residual water. The residual water on the floor surface is sucked into the casing 51 from the pump casing suction port 62 through a slight gap d between the strainer / pump leg 57 and the floor surface. At this time, the residual water inlet is formed by the strainer / pump leg 57 having a slight height of 1 to 3 mm from the floor surface, and the inlet can be sealed even with a slight residual water. Therefore, the suction pressure of the pump casing suction port 62 created by the impeller 43 idling in the air does not short-circuit with the external atmospheric pressure. Therefore, even if there is only a few mm of remaining water and the impeller 43 is in the air, the impeller 43 is quickly filled with pumped water, so that drainage work can be performed immediately.

  Further, in order to make the pump casing space in the pump casing 51 as small as possible, the impeller 43 and the front, side and rear clearances a, b and c in the casing 51 are slightly formed, and the pump casing suction port Since the suction space from 62 to the floor surface is formed as small as possible, the suction pressure can be generated in a short time even with the limited suction air volume by the impeller nut 44. Therefore, even if the amount of intake air is small, there is only a few mm of residual water on the floor surface, and even if the impeller 43 is in the air, the distance f between the impeller 43 and the floor surface is as short as possible. Thus, the remaining water can be immediately introduced into the pump impeller, pumping can be started in a short time, and the clearances a, b, and c around the impeller are reduced to make the space in the casing as small as possible. Therefore, the self-priming action occurs, and the drainage work can be continuously performed without air-locking.

  Moreover, even if the pump once sucks air and starts gas-liquid drainage, as described above, the impeller 43 has the ability to suck up the remaining water and fill the impeller 43 with water. The discharge pipe 60 provided above has a chamber 60a that temporarily stores the pumped water and increases the contact area with the outside air to serve as a gas-liquid separation chamber. The discharged gas-water mixture is subjected to a gas-liquid separation action here, the air is discharged to the outside through the hose coupling 60b, and a part of the water is returned to the pump casing 51 as necessary to be continuous. It is used to discharge air and water. Since the strainer 55 disposed in the center of the bottom plate 53 is provided with a large number of small holes, a residual water inlet with a slight height d formed by a pump leg 57 having a low height is provided. Together, sand and dust can be prevented from entering, and the impeller 43 can be prevented from clogging.

  The floor residual water drainage pump shown in FIGS. 7 and 8 is premised on speeding up, and is characterized in that an initial air suction function is provided to the impeller nut 44. By high-speed rotation (80 Hz), air can be quickly discharged by the impeller nut 44 having a relatively small outer diameter, and then the sucked water is slowly and excellently pumped by the impeller (rotation at 60 Hz) 43. Can be discharged. That is, since the impeller 43 does not require air suction capability, it is sufficient that the impeller 43 has a function and performance for efficiently discharging water. Therefore, it is more efficient than the conventional pump described in Japanese Utility Model Publication No. 2-28592 that discharges air and then discharges water by the air suction capability of the impeller itself.

  A conventional pump requires a structure that effectively releases the sliding heat of the mechanical seal when rotating at high speed during air suction. Conventionally, the sliding heat is dissipated from the outer surface of the motor frame and the outer surface of the intermediate casing via the lubricating oil of the mechanical seal. In the present invention, since the heat dissipating rib 52a is provided in the intermediate casing 52, the sliding heat can be effectively dissipated. It is known that when the mechanical seal is heated to a high temperature by sliding heat, the rubber surrounding the sliding surface and the sliding member is deteriorated and consumed quickly.

  For example, in the floor residual water drainage pump as shown in FIG. 7 which is an embodiment of the present invention, the purpose is not to discharge air but to discharge water. Therefore, when sucking air with a small specific gravity, it is extremely effective to reduce power consumption at low speed rotation, and then increase the rotation speed and complete drainage quickly when water with a large specific gravity arrives. is there.

  FIG. 9 is a graph showing an example of a driving mode of the floor residual water drainage pump shown in FIG. In this mode, when a fluid (air) having a small specific gravity is sucked, it is driven at a high speed (80 Hz), and the time is programmed to 15 minutes, for example. After 15 minutes, it is driven at a low speed (30 Hz), and it continues until water with a large specific gravity comes. When water comes in, the rotational speed increases (60 Hz) and is driven at 60 Hz until drainage is completed. When draining is complete and air is again drawn up, the speed is increased to 80 Hz, which continues for up to 15 minutes until water comes again.

  FIG. 10 is a graph showing another example of the drive mode of the floor residual water drainage pump shown in FIG. In this mode, when a fluid (air) having a small specific gravity is sucked, it is driven at a high speed (80 Hz), and the allowable time for the first time is programmed, for example, up to 20 minutes. After 20 minutes, the pump is stopped for 10 minutes and then operated for 5 minutes. If water with a large specific gravity comes during this 5 minutes, drain operation is performed at 60 Hz. If water does not come within 5 minutes, the pump is stopped for 20 minutes and the operation is continued for 5 minutes. If water comes in during this 5 minutes, drain operation is performed at 60 Hz, but if water does not come in, the pump stops for 30 minutes.

  Thereafter, similarly, the power consumption can be reduced by gradually increasing the stop time. Of course, it is possible to make the stop time constant, and it is possible to operate at about 60 Hz when high speed rotation is not necessary when sucking a fluid having a small specific gravity. This method is also effective for bearing protection of a pump using a self-lubricating type bearing in which the bearing is poorly lubricated in air.

It is a longitudinal cross-sectional view of the motor pump which is one Example of the motor drive type fluid machine which concerns on this invention. It is a top view of the motor pump shown in FIG. It is a circuit diagram which shows one Example of the frequency converter which concerns on this invention. It is a circuit diagram which shows the other Example of the frequency converter which concerns on this invention. It is a circuit diagram which shows the further another Example of the frequency converter which concerns on this invention. It is a figure which shows the structure of the frequency converter based on this invention, Fig.6 (a) is a longitudinal cross-sectional view, FIG.6 (b) is a side view. It is a longitudinal cross-sectional view of the floor residual water drainage pump which is another Example of the motor drive type fluid machine which concerns on this invention. It is a figure which shows the impeller nut of the floor residual water drainage pump shown in FIG. 7, Fig.8 (a) is a side view, FIG.8 (b) is sectional drawing. It is a graph which shows one example of the drive mode of the floor residual water drainage pump shown in FIG. It is a graph which shows the other example of the drive mode of the floor residual water drainage pump shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Barrel 2 Motor pump main body 3 1st cover 4 Pump stand 8 Annular space 10 Pump part 11, 51 Pump casing 12, 43 Impeller 13, 52 Intermediate casing 16 Motor shaft 17 Air lock prevention nut 18 Pump chamber suction port 19 Suction passage 20, 62 Pump casing suction port 21 Suction pipe 22 Suction tube 23 Circulating water suction port 24 Pump chamber discharge port 25 Discharge tube 30 Motor unit 31 Stator 32 Motor frame 33 Rotor 36 Frequency converter 37 Second cover 44 Impeller nut 57 Strainer and pump leg 59 Pump discharge port 61 Mechanical seal 71 Rectifier circuit 73 Inverter part 74 Auxiliary power supply part 75 Voltage detection part 76 Control part 77 Current detection part 78 Current detection sensor 79 Temperature sensor 81 Insulating film 82 Resin case 83 Resin material 8 Power unit

Claims (5)

In a fluid machine where the liquid to be handled or transported exists on the outer periphery of the motor stator,
A motor frame surrounding the outer periphery of the motor stator;
A pump unit provided at one end of the motor shaft;
A first cover that is provided on the other end of the motor shaft and supports the bearing;
A frequency converter provided on the non-bearing side of the first cover;
A fluid machine comprising a second cover for accommodating a frequency converter between the first cover and the first cover.   The fluid machine according to claim 1, wherein the motor frame and the first cover, and the first cover and the second cover can be independently disassembled and assembled.   The frequency converter and the power cable are fixed to the second cover to form a second cover assembly, and the first cover assembly including at least the first cover and the motor frame is formed. The fluid machine according to claim 1 or 2, wherein the second cover assembly and one kind of first cover assembly are combined so as to be compatible with a plurality of power sources.   An impeller is disposed in the vicinity of the floor surface, and is a residual water drainage pump used on a vertical shaft. The impeller nut that fixes the impeller to the main shaft is protruded from the impeller blade end toward the floor surface, and the impeller 2. The fluid machine according to claim 1, wherein a gap between the outer diameter of the wheel nut and the pump casing suction port is minimized. A frequency converter that is used in a fluid machine that is driven by a motor and sucks a plurality of fluids having different specific gravity according to circumstances, and an output unit that supplies power to a three-phase induction motor, and an input unit that is connected to a power source And a control unit that reduces the output current value by changing the output voltage and frequency based on a preset rule when the three-phase induction motor is in an overcurrent state due to an overload or the like. A frequency converter characterized by that.

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