JP2017057783A - Submerged motor-driven pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a submerged motor-driven pump which can be easily maintained.SOLUTION: A submerged motor-driven pump 100 comprises: a motor 1; a rotary shaft 2 driven by the motor 1; a pump chamber 4 in which an impeller 3 attached to the rotary shaft 2 is arranged; an oil chamber 5 arranged between the motor 1 and the pump chamber 4; a first fluid storage part 81 for storing the fluid to flow out from the oil chamber 5 to the side of the motor 1; and a fluid return passage 9 disposed inside the rotary shaft 2 and for causing the first fluid storage part 81 and the oil chamber 5 to communicate with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a submersible electric pump.

  Conventionally, a small submersible electric pump including an oil chamber in which a mechanical seal is provided between the pump chamber and the motor is known so that the pressure water in the pump chamber does not enter the motor. However, this submersible electric pump has a disadvantage that pressure water, oil, or the like entering the oil chamber from the sliding portion may flow into the motor due to wear or surface roughness of the sliding portion of the mechanical seal.

  Therefore, in order to prevent pressure water, oil, etc. from flowing into the motor, a submersible pump that shuts off the power supply to the motor by installing a submersion detection sensor in the oil chamber and detecting the submersion in the oil chamber. (Submersible electric pump) has been proposed (see, for example, Patent Document 1). In addition, an additional immersion chamber is provided between the oil chamber and the motor to prevent the pressure water in the pump chamber and the oil in the oil chamber from entering the motor, so that the inundation detector can detect inundation in the immersion chamber. Based on this, a submersible pump (submersible electric pump) having a configuration that ensures a long time until the motor is de-energized has also been proposed (see, for example, Patent Document 2).

JP 2002-310091 A JP 2007-332825 A

  However, in the submersible pump (submersible electric pump) of the above-mentioned Patent Document 1, when the water detection sensor detects that the pressure water in the pump chamber has submerged in the oil chamber, the pressure water, oil, or the like flows into the motor. In order to minimize this, it is necessary to forcibly stop the submersible pump, pull it out of the water, remove the pump casing, the oil casing, etc., perform the maintenance work, and restore the pump. In this case, in order to continue the operation, it is necessary to have a spare submersible pump and take emergency measures with the spare submersible pump. For this reason, there is a problem that a lot of labor is required for maintenance.

  Moreover, in the submersible pump (submersible electric pump) of the above-mentioned patent document 2, since a submerged pool chamber is provided between the oil chamber and the motor, it is possible to ensure a long time until the motor is deenergized. However, the construction of the submersion chamber is complicated, and at the same time, the overall height of the pump increases and the size increases. In addition, when the inundation detector detects inundation into the inundation pool chamber, the submersible pump is forcibly stopped and pulled up from the water in the same manner as the submersible pump described in Patent Document 1 to perform maintenance work. Need to be restored. In this case, in order to continue the operation, an emergency response must be made with a spare submersible pump. For this reason, there is a problem that a lot of labor is required for maintenance.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a submersible electric pump that can be easily maintained.

  An submersible electric pump according to one aspect of the present invention is disposed between a motor, a pump chamber in which a rotating shaft driven by the motor, an impeller attached to the rotating shaft is disposed, and the motor and the pump chamber. An oil chamber, a fluid reservoir that stores fluid flowing out from the oil chamber to the motor side, and a fluid return path that is provided inside the rotating shaft and communicates the fluid reservoir and the oil chamber.

  In the submersible electric pump according to one aspect of the present invention, as described above, the fluid storage section that stores the fluid flowing out from the oil chamber to the motor side, the rotary storage shaft, and the fluid storage section and the oil chamber are arranged. And a fluid return path communicating therewith. As a result, when fluid enters the fluid reservoir from the oil chamber due to intrusion of pressure water from the pump chamber into the oil chamber, the fluid that flows into the fluid reservoir from the oil chamber passes through the fluid return path. Returned to the room. Thereby, the water immersion to a motor can be suppressed effectively. Further, since the fluid containing the oil flowing out from the oil chamber is returned to the oil chamber through the fluid return path, it is not necessary to remove the pump casing, the oil casing, etc. and perform the maintenance work. Moreover, it is not necessary to have a spare submersible pump in order to continue operation. As a result, maintenance and management of the submersible electric pump can be easily performed without requiring much labor and cost for maintenance. Further, since the fluid return path is provided inside the rotating shaft, space can be saved.

  In the submersible electric pump according to the above aspect, the fluid return path preferably includes a vertical hole portion extending in the axial direction of the rotation shaft, a first communication hole communicating the vertical hole portion and the fluid storage portion, a vertical hole portion, and A second communication hole communicating with the oil chamber. If comprised in this way, a fluid return path can be easily formed by connecting a 1st communicating hole and a 2nd communicating hole to a vertical hole part.

  In this case, preferably, the vertical hole portion is provided with a pressurizing portion that applies pressure toward the oil chamber to the fluid in the fluid return path as the rotation shaft rotates. If comprised in this way, the pressure which goes to an oil chamber with respect to the fluid in a fluid return path with a pressurization part can be applied, and the flow which goes to an oil chamber from a fluid storage part can be generated in a fluid return path The fluid can be returned more effectively.

  In the configuration in which the pressurizing unit is provided, the pressurizing unit preferably includes a female screw-shaped groove provided on the inner peripheral surface of the fluid return path. If comprised in this way, a pressurization part can be easily formed in the inside of a rotating shaft by screwing, for example.

  In the submersible electric pump according to the above aspect, preferably, the fluid reservoir is a first fluid reservoir disposed between the motor and the oil chamber, and a second fluid reservoir provided in a lower portion inside the motor. At least one of the above. If comprised in this way, when a fluid storage part contains a 1st fluid storage part, it will suppress effectively that a fluid flows in into a motor by the 1st fluid storage part between a motor and an oil chamber. be able to. Moreover, when a fluid storage part contains a 2nd fluid storage part, it can suppress effectively that a fluid contacts a bearing and power part of a motor directly.

  The submersible electric pump according to the above aspect preferably further includes a backflow prevention unit that is provided in the fluid return path and prevents the fluid from flowing back from the oil chamber. With this configuration, it is possible to prevent the oil from flowing backward from the oil chamber to the motor side even when the submersible electric pump is stored sideways.

  In the submersible electric pump according to the above aspect, the return path inlet section on the fluid storage section side of the fluid return path is preferably formed along the rotation direction of the rotating shaft. If comprised in this way, since a return path inlet_port | entrance part is formed along the rotation direction of a rotating shaft, a fluid can be efficiently flowed into a fluid return path.

  In the submersible electric pump according to the above aspect, the return path outlet portion on the oil chamber side of the fluid return path is preferably formed along the rotation direction of the rotating shaft. If comprised in this way, since a return path exit part is formed along the reverse direction of the rotation direction of a rotating shaft, a fluid can be efficiently flowed out from a fluid return path.

  ADVANTAGE OF THE INVENTION According to this invention, as mentioned above, the submersible electric pump which can perform maintenance management easily can be provided.

It is the schematic which showed the submersible electric pump by 1st Embodiment of this invention. It is the side view which showed the fluid return path of the submersible electric pump by 1st Embodiment of this invention. FIG. 5 is a cross-sectional view taken along line 500-500 in FIG. 2. It is the schematic which showed the submersible electric pump by 2nd Embodiment of this invention. It is sectional drawing which looked at the horizontal cross section which passes along the 1st communicating hole of the rotating shaft of the submersible electric pump by the 1st modification of 1st and 2nd embodiment of this invention from upper direction. It is sectional drawing which looked at the horizontal cross section which passes along the 2nd communicating hole of the rotating shaft of the submersible electric pump by the 1st modification of 1st and 2nd embodiment of this invention from upper direction. It is the schematic which showed the submersible electric pump by the 2nd modification of 1st and 2nd embodiment of this invention.

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

[First Embodiment]
(Configuration of submersible electric pump)
With reference to FIGS. 1-3, the structure of the submersible electric pump 100 by 1st Embodiment is demonstrated.

  As shown in FIG. 1, the submersible electric pump 100 includes a motor 1, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a mechanical seal 6 having sliding portions 6a and 6b. An annular body 7, a first fluid storage part 81, and a fluid return path 9 are provided. The first fluid storage unit 81 is configured to store the fluid flowing out from the oil chamber 5 to the motor 1 side. The submersible electric pump 100 is a vertical submersible electric pump in which the rotating shaft 2 extends in the vertical direction (Z direction). The first fluid reservoir 81 is an example of the “fluid reservoir” in the claims.

  Here, in the submersible electric pump 100 according to the first embodiment, the fluid return path 9 is provided inside the rotating shaft 2 and is disposed between the motor 1 and the oil chamber 5. It is configured to communicate with the oil chamber 5. Accordingly, the submersible electric pump 100 is configured to return the fluid that has flowed out (ascended) from the oil chamber 5 to the first fluid storage portion 81 to the oil chamber 5 through the fluid return path 9. Details will be described later.

  The motor 1 includes a stator 11 and a rotor 12. The motor 1 is sealed so that water from the outside does not enter. Further, the motor 1 is configured to rotationally drive the impeller 3 (rotating shaft 2).

  The stator 11 has a coil. The stator 11 is disposed on the outer periphery of the motor 1. Further, the power is supplied from the cable 13 to the coil of the stator 11 so that a magnetic field is generated. The rotor 12 is disposed inside the motor 1 so as to face the stator 11. The rotor 12 is attached to the rotating shaft 2. The rotor 12 is configured to rotate by a magnetic field from the stator 11.

  The rotating shaft 2 is configured to be rotationally driven by driving of the motor 1. The rotary shaft 2 is configured to transmit the drive of the motor 1 to the impeller 3. The rotating shaft 2 is configured to rotate clockwise (clockwise) in a plan view (when viewed from above). The rotating shaft 2 is rotatably supported by bearings 21 and 22. The bearing 21 is provided on the opposite side of the motor 1 (the side opposite to the pump chamber 4). The bearing 22 is provided on the load side (pump chamber 4 side) of the motor 1. The rotating shaft 2 is arranged so as to extend from the motor 1 through the oil chamber 5 to the pump chamber 4. An impeller 3 is attached to the end of the rotary shaft 2 on the pump chamber 4 side.

  The impeller 3 is attached to the tip of the rotating shaft 2 on the opposite side (downward side) from the motor 1 side. The impeller 3 is disposed in the pump chamber 4. Moreover, the impeller 3 gives speed energy to water by rotationally driving. And it is comprised so that pressure may be acted on and sent to water, when the velocity energy of water is converted into pressure energy within the pump chamber 4. That is, by the rotational drive of the impeller 3, water is sucked up from the water suction port 41 of the pump chamber 4, and the water sucked up from the discharge port 42 is discharged.

  The oil chamber 5 is disposed between the motor 1 and the pump chamber 4, and the oil chamber 5 is filled with oil. A wall 51 is disposed on the motor 1 side of the oil chamber 5. An oil lifter 52 is provided around the rotation shaft 2 of the oil chamber 5. Also, a mechanical seal 6 having sliding portions 6a and 6b is provided in the oil chamber 5, and the sliding portions 6a and 6b are lubricated by the oil filled in the oil chamber 5, and the sliding portion 6a and 6b are configured to be cooled so as not to burn. Specifically, the sliding portion 6 a on the load side (pump chamber 4 side) of the mechanical seal 6 is provided on the pump chamber 4 side of the oil chamber 5. That is, the sliding portion 6 a on the load side (pump chamber 4 side) of the mechanical seal 6 is provided so that the pressure water in the pump chamber 4 does not enter the oil chamber 5. A sliding portion 6 b on the side opposite to the load side of the mechanical seal 6 (the side opposite to the pump chamber 4) is provided on the motor 1 side of the oil chamber 5. That is, the sliding portion 6b on the side opposite to the load side of the mechanical seal 6 (the side opposite to the pump chamber 4) is provided so that the fluid containing the oil in the oil chamber 5 does not enter the motor 1 side.

  The oil lifter 52 is provided in a cylindrical shape around the rotation shaft 2. The oil lifter 52 is configured to lift up the oil that moves as the rotary shaft 2 rotates. That is, the oil lifter 52 is configured to supply oil to the sliding portion 6b. A through hole 521 is provided in the lower part of the oil lifter 52. The oil is guided from the through hole 521 to the inner peripheral side of the oil lifter 52.

  The mechanical seal 6 includes a fixed member 61, a rotating member 62, and a spring 63. The fixing member 61 has a sliding surface 611. The rotating member 62 has a sliding surface 621. The fixing member 61 is fixed to the housing of the oil chamber 5. The fixing member 61 is formed in an annular shape so as to surround the rotating shaft 2. The rotating member 62 is attached to the rotating shaft 2. That is, the rotating member 62 is configured to rotate together with the rotating shaft 2. The rotating member 62 is formed in an annular shape so as to surround the rotating shaft 2. The rotating member 62 is urged toward the fixed member 61 by a spring 63.

  The fixed member 61 and the rotating member 62 are disposed so as to face each other in the axial direction of the rotating shaft 2. In the sliding portions 6a and 6b, the sliding surface 611 of the fixing member 61 and the sliding surface 621 of the rotating member 62 are configured to slide relative to each other. Further, the oil in the oil chamber 5 slightly enters between the sliding surfaces 611 and 621. As a result, the sliding surfaces 611 and 621 are lubricated, cooled by oil so that the sliding surfaces 611 and 621 are not burned, and the sliding portions 6a and 6b are sealed.

  The annular body 7 is provided so as to protrude from the wall 51 on the side opposite to the load side of the oil chamber 5 (the side opposite to the pump chamber 4) to the motor 1 side. The annular body 7 is provided in an annular shape so as to surround the rotation shaft 2 with a predetermined distance from the rotation shaft 2. A seal 71 is provided at the end of the annular body 7 on the motor 1 side. As the seal 71, for example, an oil seal, a seal lip, or a seal having a mechanism for generating a thrust force on the load side such as an inclined rib or a groove at a lip portion that slides with the rotary shaft 2 is used. The seal 71 is disposed between the annular body 7 and the rotary shaft 2.

As described above, the first fluid storage unit 81 is disposed between the motor 1 and the oil chamber 5.
Further, the first fluid storage part 81 is surrounded by the annular body 7. The first fluid storage part 81 communicates with the sliding part 6b (sliding surfaces 611 and 621) of the mechanical seal 6 and extends toward the motor 1 side (Z1 direction side) so as to surround the rotating shaft 2. Is formed. Further, the first fluid storage part 81 is configured such that fluid including oil leaks from the sliding part 6b on the opposite side of the mechanical seal 6 (opposite side to the pump chamber 4). Further, the end of the first fluid reservoir 81 on the motor 1 side is sealed with a seal 71.

  The fluid return path 9 is provided inside the rotating shaft 2 as described above. Further, the fluid return path 9 communicates the first fluid storage part 81 and the oil chamber 5. The fluid return path 9 includes a vertical hole portion 91, a first communication hole 92 connected to the first fluid storage portion 81, and a second communication hole 93 connected to the oil chamber 5. The fluid return path 9 is formed in a C shape when viewed from the side surface by the vertical hole portion 91, the first communication hole 92, and the second communication hole 93.

  As shown in FIG. 2, the vertical hole portion 91 is a hole portion extending in the axial direction (vertical direction) of the fluid return path 9. In addition, pressure directed toward the oil chamber 5 is applied to the vertical hole portion 91 with respect to the fluid in the fluid return path 9 that has flowed in from the first fluid storage portion 81 with the rotation of the rotary shaft 2 (the flow is generated). ) A groove portion 91a is provided. The groove portion 91a is formed in a female screw shape on the inner peripheral surface of the fluid return path 9. Moreover, the female thread shape of the groove part 91a is a shape corresponding to a reverse thread (left-hand thread). Further, the vertical hole portion 91 is located on the same axis as the rotation center α of the rotation shaft 2. The groove portion 91a is an example of the “pressurizing portion” in the claims.

  Further, the vertical hole portion 91 is formed by opening a through hole 91b from a lower end (end portion on the Z1 direction side) of the rotating shaft 2. The through hole 91b is sealed with a sealing resin 91c. Specifically, the through hole 91 b is filled with the sealing resin 91 c from the lower end (end in the Z1 direction) of the rotating shaft 2 to a height position slightly lower than the second communication hole 93. The vertical hole portion 91 is a portion on the upper side (Z1 direction side) of the sealing resin 91c of the through hole 91b sealed with the sealing resin 91c.

  As shown in FIG. 2, the first communication hole 92 is an upper (Z1 direction side) hole portion of two hole portions extending in a direction (lateral direction) intersecting the axial direction of the fluid return path 9. One end of the first communication hole 92 is connected to the upper end (Z1 direction side end) of the vertical hole portion 91. The other end of the first communication hole 92 is connected to the first fluid storage part 81. That is, the return path inlet portion 92 a into which the fluid flows into the first communication hole 92 (fluid return path 9) is connected to the first fluid storage portion 81. Further, the first communication hole 92 extends linearly in the radial direction of the rotating shaft 2 as shown in FIG. Therefore, the return path entrance portion 92 a is formed along the radial direction of the rotating shaft 2.

  As shown in FIG. 2, the second communication hole 93 is a lower (Z2 direction side) hole portion of two hole portions extending in the direction (lateral direction) intersecting the axial direction of the fluid return path 9. . One end of the second communication hole 93 is connected to the vicinity of the lower end (Z2 direction end) of the vertical hole 91. The other end of the second communication hole 93 is connected to the oil chamber 5. That is, the return path outlet portion 93 a through which the fluid flows out from the second communication hole 93 (fluid return path 9) is connected to the oil chamber 5. The second communication hole 93 extends linearly in the radial direction of the rotating shaft 2. Therefore, the return path outlet portion 93 a is formed along the radial direction of the rotating shaft 2. The return path outlet portion 93a is provided at a position where the fluid can be returned into the fluid in the oil chamber 5, for example, between the load member and the anti-load side rotating member 62. Note that the second communication hole 93 has the same shape as the first communication hole 92 and overlaps the first communication hole 92 in the vertical direction (Z direction) in FIG. 3.

  As shown in FIG. 1, the fluid return path 9 (vertical hole portion 91) is provided with a backflow prevention portion 94 that prevents the fluid from flowing back from the oil chamber 5. As an example of the backflow prevention unit 94, a pressure type on-off valve (check valve) that opens when the pressure in the oil chamber 5 becomes higher than the pressure in the first fluid storage unit 81 can be considered.

(Effect of 1st Embodiment)
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, the first fluid storage portion 81 that stores the fluid flowing out from the oil chamber 5 to the motor 1 side and the first fluid storage portion 81 and the oil are disposed inside the rotary shaft 2. A fluid return path 9 communicating with the chamber 5 is provided. As a result, when fluid enters the first fluid reservoir 81 from the oil chamber 5 due to intrusion of the pressure water of the pump chamber 4 into the oil chamber 5, the first fluid reservoir from the oil chamber 5. The fluid that has flowed into 81 is returned to the oil chamber 5 through the first fluid return path 81. Thereby, the water immersion to the motor 1 can be suppressed effectively. Further, since the fluid containing the oil flowing out from the oil chamber 5 is returned to the oil chamber 5 through the fluid return path 9, there is no need to remove the pump casing, the oil casing, etc. and perform maintenance work. Moreover, it is not necessary to have a spare submersible pump in order to continue operation. As a result, maintenance and management of the submersible electric pump 100 can be easily performed without requiring much labor and cost for maintenance. Moreover, since the fluid return path 9 is provided inside the rotating shaft 2, space saving can be achieved.

  In the first embodiment, as described above, the fluid return path 9 is connected to the vertical hole portion 91 extending in the axial direction of the rotating shaft 2, and the first communication hole 92 communicating the vertical hole portion 91 and the first fluid storage portion 81. And the 2nd communicating hole 93 which connects the vertical hole part 91 and the oil chamber 5 is provided. Accordingly, the fluid return path 9 can be easily formed by connecting the first communication hole 92 and the second communication hole 93 to the vertical hole portion 91.

  In the first embodiment, as described above, the groove portion 91 a that applies pressure toward the oil chamber 5 to the fluid in the fluid return path 9 is provided in the vertical hole portion 91 as the rotary shaft 2 rotates. As a result, the groove 91 a applies a pressure toward the oil chamber 5 to the fluid in the fluid return path 9, and a flow from the first fluid reservoir 81 toward the oil chamber 5 is generated in the fluid return path 9. As a result, the fluid can be returned more effectively.

  In the first embodiment, as described above, the groove portion 91 a is formed on the inner peripheral surface of the fluid return path 9 in a female screw shape. Thereby, the groove part 91a can be easily formed in the rotating shaft 2.

  In the first embodiment, as described above, the first fluid storage portion 81 is disposed between the motor 1 and the oil chamber 5. Thereby, it is possible to effectively prevent the fluid from flowing into the motor 1 by the first fluid storage portion 81 between the motor 1 and the oil chamber 5.

  In the first embodiment, as described above, the backflow prevention unit 94 that is disposed in the fluid return path 9 and prevents the fluid from flowing back from the oil chamber 5 is provided. Thereby, even when the submersible electric pump 100 is stored sideways, it is possible to prevent the oil from flowing backward from the oil chamber 5 to the motor 1 side.

[Second Embodiment]
(Configuration of submersible electric pump)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, an example in which a second fluid reservoir 82, a fluid ascending channel 82a, and an inundation detector 82b are further provided in addition to the configuration of the first embodiment will be described.

  As shown in FIG. 4, the submersible electric pump 200 includes a motor 1, a rotating shaft 2, an impeller 3, a pump chamber 4, an oil chamber 5, and a mechanical seal 6 having sliding portions 6a and 6b. An annular body 7, a first fluid reservoir 81 and a second fluid reservoir 82, and a fluid return path 9 are provided. The submersible electric pump 200 is a vertical submersible electric pump in which the rotary shaft 2 extends in the vertical direction (Z direction). The first fluid reservoir 81 is an example of the “fluid reservoir” in the claims.

  The second fluid reservoir 82 is provided in the lower part inside the motor 1. The second fluid storage part 82 includes a fluid rising channel 82a. The fluid ascending flow path 82 a extends in the lateral direction from the second fluid storage portion 82 toward the rotation shaft 2 so as to penetrate the annular body 7. Thereby, the fluid rising flow path 82 a is configured to communicate the space portion 72 adjacent to the rotating shaft 2 and the motor 1. The space 72 is an area located inside the annular body 7 and sandwiched between the bearing 22 and the seal 71.

  In addition, the second fluid storage unit 82 is provided with a flood detection unit 82b. The inundation detection unit 82b is made of a conductive material, and the second inflow is established by establishing conduction between the casing of the submersible electric pump 200, the infiltration detection unit 82b, and the water that has entered the second fluid storage unit 82. It has a function of detecting that water has entered the fluid reservoir 82. The submersible electric pump 200 is configured to perform various controls such as stopping the motor 1 and issuing an alarm to the user based on the detection result of the inundation detection unit 82b.

  In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

(Effect of 2nd Embodiment)
In the second embodiment, the following effects can be obtained.

  In the second embodiment, similarly to the first embodiment, the first fluid storage part 81 that stores the fluid flowing out from the oil chamber 5 to the motor 1 side and the rotary shaft 2 are disposed, and the first fluid storage is performed. A fluid return path 9 that communicates the portion 81 and the oil chamber 5 is provided. Thereby, maintenance management of submersible electric pump 200 can be performed easily.

  In the second embodiment, as described above, the second fluid reservoir 82 is provided in the lower part of the motor 1. Thereby, even when the fluid flows out above the first fluid storage part 81, the fluid can be stored in the second fluid storage part 82, so that the fluid directly contacts the bearing or the power part of the motor 1. Can be effectively suppressed.

  In the second embodiment, the second fluid storage unit 82 is provided with the inundation detection unit 82b as described above. Thereby, it is possible to notify the user that the flooding has occurred by stopping the operation of the submersible electric pump 200 or issuing an alarm when the flooding detection unit 82b detects the flooding.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Modification)
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the said 1st and 2nd embodiment, although the example which formed the return path entrance part of the 1st communicating hole along the radial direction of a rotating shaft was shown, this invention is not limited to this. In the present invention, the return path inlet portion 921a of the first communication hole 921 may be formed along the rotation direction of the rotary shaft 2 like the fluid return path 9a of the first modification shown in FIG. If comprised in this way, since the return path entrance part 921a is formed along the rotation direction of the rotating shaft 2, a fluid can be efficiently flowed into the fluid return path 9a.

  Moreover, in the said 1st and 2nd embodiment, although the return path entrance part of the 2nd communicating hole was formed so that it might follow the radial direction of a rotating shaft, this invention is not limited to this. In the present invention, like the fluid return path 9a of the first modification shown in FIG. 6, the return path inlet / outlet portion 931a of the second communication hole 931 is formed along the direction opposite to the rotation direction of the rotary shaft 2. Also good. If comprised in this way, since the return path entrance / exit part 931a is formed along the reverse direction of the rotation direction of the rotating shaft 2, a fluid can be efficiently flowed out from the fluid return path 9a. In FIG. 6, the first communication hole 921 shown in FIG. 5 is indicated by a two-dot chain line. As indicated by a two-dot chain line, the return path entrance portion 921a and the return path entrance / exit portion 931a are provided at positions overlapping each other in the vertical direction (Z direction).

  In the first and second embodiments, the first communication hole and the second communication hole are linearly formed. However, the present invention is not limited to this. In the present invention, like the fluid return path 9a of the first modification shown in FIGS. 5 and 6, the first communication hole 921 and the second communication hole 931 swell in the reverse direction and the rotation direction, respectively. You may form in a curved shape.

  Moreover, although the example which provided the mechanical seal in both the pump chamber side and motor side of the oil chamber was shown in the said 1st and 2nd embodiment, this invention is not limited to this. In the present invention, the mechanical seal 6 may be provided only on the pump chamber 4 side of the oil chamber 5 as in the submersible electric pump 300 of the second modification shown in FIG. The mechanical seal 6 has a sliding part 6a. The mechanical seal 6 is configured so that the sliding portion 6a is lubricated by the oil filled in the oil chamber 5 and cooled so that the sliding portion 6a does not burn. The mechanical seal 6 includes a fixed member 61, a rotating member 62, a spring 63, and a support member 64. The rotating member 62 is biased toward the fixed member 61 by a spring 63. The spring 63 is in contact with the rotating member 62 on the pump chamber 4 side, and is in contact with the support member 64 on the motor 1 side. The support member 64 is configured to support the upper side of the spring 63. The support member 64 is attached to the rotary shaft 2. The support member 64 is formed in an annular shape. A seal 65 that seals the oil chamber 5 and the first fluid storage portion 81 is provided at the upper end of the oil chamber 5. If comprised in this way, since the liquid level in the oil chamber 5 can be made low compared with the case where a mechanical seal is provided in the upper and lower sides of an oil chamber, the return path exit part 93a is made into the liquid level in the oil chamber 5. Can be provided at a higher position. Further, the risk of fluid flowing out from the oil chamber 5 to the motor 1 side can be reduced, and there is no need to provide the oil lifter 52 in the oil chamber 5.

  Moreover, in the said 2nd Embodiment, although the example comprised so that a fluid might be returned to an oil chamber from a 1st fluid storage part was shown, this invention is not limited to this. In the present invention, the fluid may be returned from the second fluid reservoir to the oil chamber. Moreover, you may comprise a fluid return path so that a fluid can be returned from both a 1st fluid storage part and a 2nd fluid storage part. In this case, the fluid return path is provided with two first communication holes, and the fluid return path is configured to branch into two in the middle of the vertical hole portion.

  Moreover, although the example which formed the through-hole from the lower side (impeller side) of the rotating shaft was shown in the said 1st and 2nd embodiment, this invention is not limited to this. In this invention, you may form a through-hole from the upper side (motor side) of a rotating shaft.

  Moreover, although the example which provided the groove part as an example of the pressurization part of this invention in the fluid return path in the said 1st and 2nd embodiment was shown, this invention is not limited to this. In the present invention, for example, a screw or the like may be provided as a pressurizing part in the fluid return path.

  Moreover, in the said 1st and 2nd embodiment, although the example which sealed the through-hole with sealing resin was shown, this invention is not restricted to this. In the present invention, for example, the through hole may be sealed with a screw and a screw seal wound around the screw.

  Moreover, although the said 1st and 2nd embodiment showed the example comprised so that a vertical hole part and the rotation center of a rotating shaft may be located on the same axis line, this invention is not limited to this. In this invention, it is not necessary to comprise so that a vertical hole part and the rotation center of a rotating shaft may be located on the same axis line.

DESCRIPTION OF SYMBOLS 1 Motor 2 Rotating shaft 3 Impeller 4 Pump chamber 5 Oil chamber 9, 9a Fluid return path 81 1st fluid storage part (fluid storage part)
91 Vertical hole portion 91a Groove portion (pressurizing portion)
92, 921 First communication hole 92a, 921a Return path inlet 93, 931 Second communication hole 93a, 931a Return path outlet 94 Backflow prevention unit 100, 200, 300 Submersible electric pump

Claims (8)

A motor,
A rotating shaft driven by the motor;
A pump chamber in which an impeller attached to the rotating shaft is disposed;
An oil chamber disposed between the motor and the pump chamber;
A fluid reservoir that stores fluid flowing out from the oil chamber to the motor side;
A submersible electric pump provided with a fluid return path provided inside the rotating shaft and communicating the fluid reservoir and the oil chamber.   The fluid return path includes a vertical hole portion extending in the axial direction of the rotating shaft, a first communication hole communicating the vertical hole portion and the fluid storage portion, and a second communication communicating the vertical hole portion and the oil chamber. The submersible electric pump according to claim 1 including a communicating hole.   The underwater according to claim 2, wherein the vertical hole portion is provided with a pressurizing portion that applies a pressure toward the oil chamber to the fluid in the fluid return path as the rotating shaft rotates. Electric pump.   The submersible electric pump according to claim 3, wherein the pressurizing unit includes a female screw-shaped groove provided on an inner peripheral surface of the fluid return path.   The fluid reservoir includes at least one of a first fluid reservoir disposed between the motor and the oil chamber, and a second fluid reservoir provided in a lower portion inside the motor. The submersible electric pump of any one of -4.   The submersible electric pump according to any one of claims 1 to 5, further comprising a backflow prevention unit that is provided in the fluid return path and prevents backflow of fluid from the oil chamber.   The submersible electric pump according to any one of claims 1 to 6, wherein a return path inlet section on the fluid storage section side of the fluid return path is formed along the rotation direction of the rotation shaft.   The submersible electric pump according to any one of claims 1 to 7, wherein a return path outlet portion on the oil chamber side of the fluid return path is formed along a direction opposite to a rotation direction of the rotation shaft. .

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