JP2012057551A - Cooling liquid circulation structure of pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure by which the shaft 35 of the motor 3 can be shortened by chemical simplifying the installing structure of the circulation impeller 7, in the cooling liquid circulation structure of the pump 1 having the circulation impeller 7 for the circulation of the cooling liquid for cooling the motor 3.SOLUTION: The cooling liquid circulation structure of the pump includes at least rotation rings 52, 54, fixed rings 51, 55, and the compression spring 53, and has the mechanical seal 5 sealing the shaft 35 between the pump part 21 and the motor part 22, and the circulation impeller 7 arranged in the shaft 35 and circulating the cooling liquid in the cooling liquid circulation flowing passage by rotating along with the shaft 35. The circulation impeller 7 is fixed to the shaft 35 so as to rotate along with the shaft 35 by the biasing force of the compression spring 53 of the mechanical seal 5.

Description

  The technology disclosed herein relates to a coolant circulation structure for cooling a motor that is a drive source of a pump.

  For example, in Patent Document 1, as a structure for cooling an electric motor of a submersible pump, an outer casing is disposed on the outer side of a casing that houses the electric motor, and a circumferential cooling oil flow path is defined on the outer periphery of the casing. In addition, a structure is disclosed in which an impeller for circulating the cooling oil is attached to the rotating shaft of the motor in the cooling oil chamber provided between the electric motor and the impeller while being communicated with the cooling oil passage. Yes.

Japanese Utility Model Publication No.59-43695

  By the way, in the mounting structure of the circulating impeller described in Patent Document 1, the circulating impeller is disposed between the upper mechanical seal and the lower mechanical seal disposed in the cooling oil chamber. At the same time, the hub of the circulating impeller extrapolated to the rotating shaft of the motor is fixed to the rotating shaft with a key. The mounting of the circulating impeller using such a key complicates the mounting structure and increases the manufacturing cost.

  Further, in the structure in which the hub of the circulating impeller is directly fixed to the rotating shaft, a mounting space corresponding to the axial length of the hub must be secured, and the motor rotating shaft becomes longer accordingly. End up. An increase in the rotational axis of the motor causes a problem that the amount of deflection caused by the fluid force acting on the impeller is increased and the vibration during driving of the pump is also increased.

  The technology disclosed herein has been made in view of such a point, and the object is to provide a coolant circulation structure of a pump including a circulation impeller for circulation of a coolant that cools a motor. Another object of the present invention is to provide a structure capable of simplifying the mounting structure of the circulating impeller and shortening the motor shaft.

  The technology disclosed herein relates to a coolant circulation structure of a pump, and includes a pump unit including an impeller, a shaft extending in a predetermined axial direction and connected to the impeller, and the impeller through the shaft. Coolant is circulated between the motor unit including the motor to be driven, the mechanical seal that is disposed between the pump unit and the motor unit, and seals the shaft, and between the motor unit side and the pump unit side And a coolant circulation passage for cooling the motor.

  The mechanical seal includes at least a rotary ring fixed to the shaft, a fixed ring attached to the pump housing side, and a compression spring that presses the rotary ring and the fixed ring against each other in the axial direction by an urging force thereof, The coolant circulation structure of the pump further includes a circulation impeller that circulates the coolant in the coolant circulation passage by being attached to the shaft and rotating together with the shaft, The shaft is attached to the shaft so as to rotate together with the shaft by the biasing force of the compression spring of the mechanical seal. Here, the “cooling liquid” includes both cooling oil and cooling water. Among these, the cooling water is not limited to water alone, and additives such as for corrosion prevention are added to water as a main component. Cooling water may be included.

  According to this configuration, the mechanical seal disposed between the pump unit and the motor unit seals the shaft, thereby preventing water or the like from entering the motor unit side. The mechanical seal may be a mechanical seal having a general structure including at least a rotating ring, a stationary ring, and a compression spring.

  The pump further includes a coolant circulation passage through which a coolant for cooling the motor flows, and a circulation impeller attached to the shaft to circulate the coolant in the coolant circulation passage. The motor is forcibly cooled.

  Then, the circulating impeller is attached to the shaft so as to rotate together with the shaft by the biasing force of the compression spring of the mechanical seal, and the circulating impeller is attached using the structure of the mechanical seal. Thus, the mounting structure is extremely simplified. In addition, the installation using the structure of the mechanical seal reduces the space required for the installation of the circulating impeller and the length of the motor shaft compared to the configuration in which the circulating impeller is attached to the shaft separately from the mechanical seal. It can be shortened by that much. This can be advantageous in reducing the amount of deflection of the shaft and suppressing vibration.

  The circulation impeller includes a ring-shaped main body portion in which a plurality of blades are arranged in the circumferential direction, a receiving portion that is provided integrally with the main body portion, and receives a biasing force of the compression spring; The circulating impeller is attached to the shaft by the receiving portion being sandwiched between an end portion of the compression spring and the rotating ring, and the main body portion is an outer periphery of the mechanical seal. In, it is good also as arrange | positioning in the position which overlaps with the said axial direction with respect to the said mechanical seal.

  The mounting structure of the circulating impeller is simplified by attaching the circulating impeller having the main body portion and the receiving portion to the shaft so that the receiving portion is sandwiched between the end of the compression spring and the rotating ring. . At the same time, the attachment of the circulating impeller to the shaft can be performed in association with the attachment of the mechanical seal to the shaft, and the attachment process can be simplified.

  In the circulation impeller thus attached to the shaft, the main body portion having the blades is disposed at a position overlapping the mechanical seal in the axial direction on the outer periphery of the mechanical seal. That is, the mechanical seal and the circulating impeller are disposed at substantially the same position with respect to the axial direction of the shaft. This eliminates the need to bother to secure a space for attaching the circulating impeller in the axial direction of the shaft, in addition to the space for attaching the mechanical seal, and can further reduce the length of the shaft. Further, although the receiving portion of the circulating impeller is sandwiched between the compression spring and the rotating ring, the compression spring is contracted, and therefore, the overall length of the mechanical seal can be suppressed. Therefore, this configuration is a more advantageous configuration for greatly shortening the length of the shaft.

  By the way, the pump of the specification which omitted the cooling structure of the electric motor is unnecessary for the pump of the specification having the cooling structure provided with the circulation impeller as disclosed in Patent Document 1, for example. To some extent, the length of the motor shaft can be shortened. However, due to the difference in specifications with or without the circulation impeller, the design of the pump is significantly changed and the parts are also different. This can cause an increase in cost.

  On the other hand, in the above-described configuration, in the natural cooling specification pump in which the cooling liquid circulation structure of the pump is omitted with respect to the forced cooling specification having the cooling liquid circulation structure, the circulation impeller is omitted as in the conventional case. However, as described above, since there is no space for attaching the circulating impeller in the forced cooling pump, no space is generated in the axial direction of the shaft even if the circulating impeller is omitted. This produces an advantage that the design and parts of the pump including the shaft can be made common regardless of the difference in the specification of the presence or absence of the coolant circulation structure of the pump. Further, as described above, the configuration in which the circulation impeller is attached by the urging force of the compression spring can absorb the presence / absence of the circulation impeller, that is, the presence / absence of the receiving portion, by the expansion and contraction of the compression spring. It can be advantageous for common use.

  As described above, the circulation impeller is not a separate structure from the rotating ring of the mechanical seal, and the circulating impeller and the rotating ring may be provided integrally. In this way, the rotating impeller is urged by the compression spring, so that the circulating impeller is attached to the shaft so as to rotate together with the shaft. However, regardless of the presence or absence of the coolant circulation structure of the pump, it is preferable that the circulation impeller and the rotating ring are separate from each other in order to share pump parts.

  The motor unit is disposed at a predetermined interval with respect to an outer peripheral surface of the motor casing and a motor casing that houses the motor, and between the outer peripheral surface of the motor casing and the coolant circulation passage. An outer casing that forms a circumferential flow path that forms part of the housing; and a housing that is attached to a lower end opening of the motor casing and the outer casing and through which the shaft passes. Are each opened into the circumferential channel, an inlet through which the coolant flows from the circumferential channel, an outlet from which the coolant flows into the circumferential channel, and the inlet A communication chamber that forms a part of the coolant circulation flow path by communicating with the outlet and a part thereof by the pump unit. The mechanical seal is attached to the shaft in the communication chamber, whereby the circulation impeller is disposed in the communication chamber, the circulation impeller is an axial flow type, and the motor unit side It is good also as being attached to the shaft so that the cooling fluid may flow along the axial direction toward the pump part side.

  As the mechanical seal is attached to the shaft in the communication chamber of the housing through which the shaft passes, the circulation impeller is arranged in the communication chamber. Accordingly, when the circulating impeller rotates with the rotation of the shaft, the coolant flows from the circumferential flow path on the motor side to the inlet, the communication chamber (circulating impeller), and the outlet in this order. By returning to this flow path, it circulates in the coolant circulation flow path.

  Here, the circulating impeller is made into an axial flow type, and the cooling liquid flows from the motor unit side to the pump unit side, so that the cooling liquid that receives heat from the motor in the motor unit is Then, after the heat exchange with the pump handling liquid, that is, the liquid having a relatively low temperature, the flow returns to the motor part side. Here, along with the axial flow type circulating impeller flowing the coolant along the axial direction from the motor unit side to the pump unit side, on the wall surface on the pump unit side that partitions a part of the communication chamber, A coolant having a relatively high flow velocity collides, and a turbulent flow of the coolant can occur in the vicinity of the wall surface. This can increase the efficiency of heat exchange between the coolant and the liquid handled by the pump, and thus can increase the cooling efficiency of the motor.

  In this configuration, since the mechanical seal is immersed in the coolant in the communication chamber, the coolant can be a lubricating fluid for the mechanical seal.

  The motor unit further includes a partition member attached to the housing, the partition member separating the communication chamber into a space on the inlet side and a space on the outlet side, and the axial flow type circulation. An impeller casing that surrounds the outer periphery of the impeller and that communicates the space on the inlet side and the space on the outlet side may be included.

  By doing so, the space on the inlet side in the communication chamber, in other words, the space where the coolant having a relatively high temperature exists by flowing in from the motor side, the space on the outlet side, in other words, The space where the cooling liquid having a relatively low temperature through heat exchange on the pump side is present is separated by a partition wall, while the space on the inlet side and the space on the outlet side are mutually separated by the impeller casing. Can communicate. Then, the impeller casing surrounds the outer periphery of the axial-flow circulation impeller, so that the coolant flows from the inlet side space through the impeller casing to the outlet side as the circulation impeller rotates. Efficiently flows into space. That is, this configuration can increase the cooling efficiency of the motor by efficiently circulating the coolant.

  As described above, in the coolant circulation structure of the pump disclosed herein, the circulation impeller for circulating the coolant is attached to the shaft so as to rotate together with the shaft by the biasing force of the compression spring of the mechanical seal. Thus, the mounting structure can be greatly simplified, the space required for mounting the circulating impeller can be reduced, and the length of the motor shaft can be shortened. As a result, the amount of shaft deflection and vibration can be reduced.

It is a longitudinal cross-sectional view of a submersible pump. It is a longitudinal cross-sectional view which expands and shows the housing vicinity of a submersible pump. It is a top view of a housing. It is sectional drawing which shows the attachment structure to the shaft of a mechanical seal and a circulating impeller. It is an exploded view of a mechanical seal and a circulating impeller. (A) The top view of a circulating impeller, (b) It is the bb sectional view taken on the line of a circulating impeller.

  Hereinafter, an embodiment of a coolant circulation structure of a pump will be described based on the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  1 and 2 show a submersible pump 1 as an example of a pump to which a coolant circulation structure of the pump is applied. The submersible pump 1 is a pump that can be used as, for example, a pump for a sewer. The submersible pump 1 includes a pump unit 21 having an impeller 23 and a motor unit 22 having a motor 3 that drives the impeller 23. The submersible pump 1 is arranged side by side in the vertical direction so that the pump unit 21 is relatively on the lower side and the motor unit 22 is relatively on the upper side, whereby the shaft 35 of the motor 3 is arranged in the vertical direction (that is, , Corresponding to a predetermined axial direction). As will be described in detail later, the submersible pump 1 also circulates a coolant between the motor unit 22 side and the pump unit 21 side, thereby cooling the motor 3 to a coolant circulation channel (circular cooling). It is a forced cooling specification provided with the liquid flow path 37 and the communication chamber 48). Here, the coolant that circulates in the coolant circulation channel is coolant in which water is a main component in this example and an additive for preventing corrosion is added thereto. However, the coolant may be composed of cooling oil.

  The motor unit 22 includes a motor 3 including a stator 31 and a rotor 32, and a motor casing 33 that supports the stator 31 and accommodates the motor 3 therein. As described above, the shaft 35 of the motor 3 integrated with the rotor 32 extends in the vertical direction.

  The motor casing 33 has a substantially cylindrical main body portion 331 whose lower end is opened, and the upper end opening of the main body portion 331 is closed by a lid portion 332 formed integrally with the main body portion 331. . A bearing 351 is attached to the lower surface of the lid portion 332, and this bearing 351 pivotally supports the upper end portion of the shaft 35. A substantially cylindrical extension portion 333 is provided integrally with the main body portion 331 so as to extend the main body portion 331 upward above the lid portion 332 of the motor casing 33. A flange 334 having an enlarged diameter is provided at the upper end of the extension 333, and the head cover 34 is attached to the flange 334. Thus, the head cover 34 and the extension portion 333 define a housing space 341 for housing various electrical components. The head cover 34 is attached with a cable boot through which a power supply cable for supplying power to the motor 3 is inserted.

  The motor unit 22 is also provided with an outer casing 36 so as to surround the outer periphery of the motor casing 33 with a predetermined gap from the outer peripheral surface of the motor casing 33. The outer casing 36 has a substantially cylindrical shape with openings at both ends, and its upper end is fixed to the flange 334 of the extension 333. Thus, the circumferential coolant flow path 37 through which the coolant flows by the outer peripheral surface of the motor casing 33 and the inner peripheral surface of the outer casing 36 surrounds the motor 3 and the shafts of the motor casing 33 and the outer casing 36. It is formed so as to spread over the entire direction. The coolant channel 37 constitutes a part of the coolant circulation channel.

  Note that lower ends of the motor casing 33 and the outer casing 36 are closed by the housing 4. Details of the housing 4 will be described later.

  The pump unit 21 includes an impeller 23 attached to the lower end of the shaft 35 of the motor 3 and a pump casing 24 that houses the impeller 23. This submersible pump 1 is a centrifugal pump provided with a centrifugal impeller 23.

  The pump casing 24 includes a casing body 241 including a spiral chamber 25 that houses the impeller 23 therein, and a lid casing that is attached and fixed to the upper end portion of the casing body 241 to separate the pump section 22 and the motor section 21. 242 and a bottom casing 243 that is attached to an opening formed in the lower end portion of the casing main body 241 and forms an inlet 245 of the pump casing 24.

  The casing body 241 communicates with the spiral chamber 25 and has a discharge port 26 that is integrally formed so as to protrude to the side of the casing body 241, and this discharge port 26 is connected to a discharge pipe (not shown). Connected.

  The upper part of the vortex chamber 25 in the casing main body 241 opens upward, and the upper part of the vortex chamber 25 is partitioned by attaching the lid casing 242 to the opening. The lid casing 242 has a substantially disk shape, and a through hole through which the shaft 35 is disposed is formed in the center of the lid casing 242 so as to penetrate in the thickness direction. An oil seal 232 that seals with the boss portion 231 of the impeller 23 is attached to the lower surface side of the lid casing 242.

  Although the lid casing 242 will be described in detail later, the housing 4 is attached and fixed to the upper surface side of the lid casing 242 to form a communication chamber 48 that constitutes a part of the coolant circulation passage together with the housing 4. A fixing portion 244 (that corresponds to the pump housing side) for fixing a lower fixing ring 55 in a mechanical seal 5 to be described later is formed on the upper surface of the lid casing 242 so as to surround the through hole of the shaft 35. (See also FIG. 4).

  A lower portion of the spiral chamber 25 in the casing body 241 opens downward, and a bottom casing 243 is attached to the opening. The bottom casing 243 is formed with a through hole 245 penetrating in the vertical direction. When the bottom casing 243 is attached to the casing body 241, the bottom casing 243 supports the lower end portion of the impeller 23 and forms an inlet 245 communicating with the suction port 232 of the impeller 23.

  In this embodiment, the impeller 23 is a non-clog type impeller, and the suction port 233 opens downward on the lower surface of the impeller, and the discharge port is a side surface of the impeller, although illustration is omitted. In FIG. In addition, the format of the impeller 23 is not limited to the format illustrated in FIG. 1, and various types of impellers can be appropriately employed.

  The housing 4 is attached to the lower end of the motor casing 33 and the lower end of the outer casing 36, thereby closing the lower end opening of the motor casing 33 and the lower end opening of the outer casing 36. As shown in FIG. 3, the housing 4 is also arranged with an upper member 41 attached to the lower end of the motor casing 33, a predetermined interval in the vertical direction (axial direction) with respect to the upper member 41, and the outer member 41. The lower member 42 attached to the lower end of the casing 36 includes a plurality of ribs 43 that are arranged at predetermined locations in the circumferential direction and connect the upper member 41 and the lower member 42 to each other.

  The upper member 41 includes a substantially cylindrical peripheral wall portion 411 having the same diameter as the motor casing 33 and extending in the axial direction, and a bottom wall portion 412 that is continuous with the lower end of the peripheral wall portion 411 and closes the lower end opening of the peripheral wall portion 411. Including a vertical U-shaped section. The upper member 41 is attached and fixed to the lower end of the motor casing 33 (main body portion 331) whose upper end of the peripheral wall portion 411 is substantially cylindrical in shape with an O-ring interposed therebetween, thereby opening the lower end opening of the motor casing 33. Block.

  A through hole 413 that penetrates in the thickness direction is formed in the bottom wall portion 412 of the upper member 41 in the center position, and the shaft 35 of the motor 3 is disposed through the through hole 413.

  The upper member 41 also has a predetermined diameter on the inner side in the radial direction so as to surround the through hole 413 for the shaft 35 and is erected upward in the axial direction from the bottom wall portion 412. A cylindrical upright wall portion 414 is formed integrally with the bottom wall portion 412. This standing wall portion is a bearing holder 414 for holding a bearing 352 that pivotally supports an intermediate portion of the shaft 35 of the motor 3. In addition, below, the same code | symbol 414 may be attached | subjected with respect to the member name of both a standing wall part and a bearing holder. Two bearings 352 and 352 are fitted in the bearing holder 414 while being aligned in the axial direction, thereby holding the two bearings 352. Here, the bearing 352 is held by the bearing holder 414 so that the lowermost part thereof is positioned above the bottom of the bearing holder 414 by a predetermined amount. This is to prevent the bearing 352 from coming into contact with water even when water is flooded, as will be described later.

  A lower portion of the upper member 41 has a fixing portion 415 to which an upper fixing ring 51 of a mechanical seal 5 described later is fixed (see also FIG. 4). This fixing portion 415 corresponds to the pump housing side. The upper member 41 (housing 4) is configured to hold the bearing 352 on the upper surface side, and to fix the mechanical seal 5 on the lower surface side, and has a plurality of functions.

  In the upper member 41, an annular space that opens upward is formed between the bearing holder 414 on the radially inner side and the peripheral wall portion 411 on the radially outer side, and this annular space passes through the through hole 413 and is connected to the motor. When inundation occurs on the part 22 side, it functions as an inundation reservoir chamber 416 for accumulating the infiltrated water. Accordingly, the housing 4 is formed with a submerged pool chamber 416 at substantially the same position in the axial direction with respect to the bearing holder 414 so as to surround the bearing holder 414. As shown in FIGS. 2 and 3, the submersion chamber 416 is formed with a recessed portion 417 that is recessed at a portion corresponding to a predetermined angular range in the circumferential direction so as to be lower than other portions. The bottom surface of the recessed portion 417 is located below the bottom surface of the bearing holder 414. Then, a drill hole 418 communicating with the bottom portion in the bearing holder 414 and the recessed portion 417 of the submerged reservoir 416 passes through the bearing holder (standing wall portion) 414 from the inside in the radial direction. It is formed to extend obliquely downward toward the direction. As described above, when the water is generated on the motor unit 22 side (inside the bearing holder 414) through the through-hole 413, the drill hole discharges the water that has entered into the water-immersion chamber 416 (that is, the recessed portion 417). This is a drain hole 418 for preventing the bearing 352 from being flooded.

  In the recess 417, a liquid level sensor 45 for detecting water intrusion toward the motor unit 22 is disposed. The liquid level sensor 45 is attached to a lid member 44, which will be described later, and is disposed so as to extend downward in the recessed portion 417, and its detection height is set to be lower than the lowest end of the bearing 352. (See the dashed line in FIG. 2). This is also advantageous in avoiding flooding of the bearing 352.

  A substantially disc-shaped lid member 44 is fixed to the upper end of the upper member 41 using a screw hole formed in the bearing holder (standing wall portion) 414. An O-ring is interposed between the outer peripheral edge of the lid member 44 and the upper end portion of the peripheral wall portion 411 of the housing 4, and the lid member 44 is the upper end of the annular water storage chamber 416 (including the recessed portion 417). Covering the opening, the water storage chamber 416 is sealed in a state of being isolated from the motor casing 33 in which the motor 3 is accommodated.

  The lid member 44 also extends radially inward from the bearing holder (standing wall portion) 414, thereby abutting against the bearing 352 held in the bearing holder 414, and It functions as a presser. That is, the lid member 44 serves as both a lid that closes the submerged reservoir chamber 416 and a bearing retainer. Note that a through-hole through which the shaft 35 of the motor 3 is disposed is formed at the center position of the lid member 44.

  Further, the liquid level sensor 45 is attached to a predetermined position in the circumferential direction of the lid member 44, specifically, a circumferential position corresponding to the recessed portion 417 of the submerged reservoir 416. The lid member 44 further includes Also, it has a function as a support member of the sensor.

  The lower member 42 has a substantially annular shape, and the upper end portion thereof is an internal fitting portion 421 that opens upward and is fitted into the lower end portion of the outer casing 36. A lower end opening 422 having a smaller diameter than the opening of the inner fitting portion 421 and opening downward is formed. The upper member 41 and the lower member 42 are connected by the rib 43 at a relative position such that a part of the lower end portion of the upper member 41 is inserted into the opening of the inner fitting portion 421 of the lower member 42. ing. The lower member 42 closes the lower end opening of the outer casing 36 by fitting the inner fitting portion 421 to the lower end of the substantially cylindrical outer casing 36 with an O-ring interposed therebetween. The lower end portion is attached and fixed to the lid casing 242 of the pump portion 21 with an O-ring interposed.

  Then, as shown in FIG. 3, the outer periphery of the housing 4 is directed radially outwardly between the rib 43 and the rib 43 that connect the upper member 41 and the lower member 42. Two inflow ports 46 and two outflow ports 47 that open and communicate with the circumferential coolant flow path 37 are formed. The inflow ports 46 and the outflow ports 47 are alternately arranged in the circumferential direction, so that the two inflow ports 46 are opposed to each other across the central axis, and the two outflow ports 47 are also relative to each other across the central axis. is doing. The inflow port 46 and the outflow port 47 communicate with each other via a communication chamber 48 formed between the upper member 41 and the lower member 42. More specifically, as shown in FIGS. 2 and 3, in the angle range corresponding to the outlet 47 in the lower member 42, an arc-shaped slit penetrating in the thickness direction outside the lower end opening 422 in the radial direction. 423 is formed. On the other hand, such a slit is not formed in the angle range corresponding to the inflow port 46. The communication chamber 48 is also defined by the upper member 41, the lower member 42, and the lid casing 242 by attaching the lower end of the housing 4 (lower member 42) to the lid casing 242 of the pump unit 21. Is done. Therefore, the inflow port 46 and the outflow port 47 communicate with each other through the communication chamber 48 and the slit 423, as is apparent from FIG.

  A partition wall member 6 that closes a part of the opening is attached to the lower end opening 422 of the lower member 42. The partition wall member 6 is disposed on the radially inner side of the partition wall 61 separating the communication chamber 48 defined by the housing 4 and the lid casing 242 into a space on the housing 4 side and a space on the lid casing 242 side. Thus, an impeller casing 62 that accommodates a circulating impeller 7 described later is integrated. More specifically, the partition wall member 6 is a thin disk-shaped flat plate part that constitutes a part of the partition wall 61 and a cylinder on the radially inner side, as also shown in FIG. The cylindrical portion that is arranged so that the shaft is coaxial with the shaft 35 of the motor 3 and constitutes the impeller casing 62, and the flat plate portion and the cylindrical portion are connected to each other from the radially inner edge of the flat plate portion. And an inclined portion that constitutes a part of the partition wall 61 so as to protrude toward the lower end of the partition wall 61. This partition member 6 may be constituted by, for example, a pressed metal thin plate. The outer peripheral edge of the partition member 6 is fixed to the edge of the lower end opening 422 of the lower member 42, so that the communication chamber 48 defined by the housing 4 and the lid casing 242 is separated from the partition 61 ( While the space on the housing 4 side and the space on the lid casing 242 side are separated by the flat plate portion and the inclined portion), the space on the housing 4 side and the space on the lid casing 242 side are mutually separated by the impeller casing 62 (cylindrical portion). You will communicate. In the impeller casing 62, the shaft 35 of the motor 3 and the mechanical seal 5 are inserted, and the circulation impeller 7 is also disposed in the impeller casing 62.

  The mechanical seal 5 is attached to the shaft 35 of the motor 3 in the communication chamber 48, so that the shaft 35 is sealed (sealed) between the motor unit 22 side and the pump unit 21 side. As shown in FIGS. 4 and 5, the mechanical seal 5 includes an upper fixed ring 51, an upper rotary ring 52, a compression spring 53, a lower rotary ring 54, and a lower fixed ring from the upper side to the lower side in the axial direction. They are arranged in the order of 55. Among these, the upper fixed ring 51 is fixed to the fixing portion 415 formed on the lower surface of the upper member 41 in the housing 4 as described above. The upper rotary ring 52 includes an extrapolation portion 521 that is extrapolated to the shaft 35 of the motor 3 and a flange portion 522 that abuts on the upper end portion of the compression spring 53, and the extrapolation portion 521 is extrapolated to the shaft 35. In this state, the flange portion 522 is pushed upward by the urging force of the compression spring 53, thereby being pushed by the upper fixed ring 51. Similarly, the lower fixing ring 55 is fixed to the fixing portion 244 formed on the upper surface of the lid casing 242 as described above. Further, the lower rotary ring 54 has an extrapolated portion 541 that is extrapolated to the shaft 35 of the motor 3 and a flange portion 542 that a lower end portion of the compression spring 53 contacts, and the extrapolated portion 541 is attached to the shaft 35. In the externally inserted state, the flange portion 542 is pressed downward by the urging force of the compression spring 53, thereby pressing the lower fixed ring 55. The compression spring 53 is a relatively large-diameter coil spring that is extrapolated to the shaft 35 of the motor 3, and the mechanical seal 5 shown here is formed by the one compression spring 53 with the upper rotary ring 52 and the lower rotary ring 54. Both rotating rings are configured to be pressed against each of the upper fixed ring 51 and the lower fixed ring 55. As shown in FIGS. 1 and 2, the mechanical seal 5 is immersed in the coolant because it is disposed in the communication chamber 48. For this reason, the cooling liquid functions not only as the cooling of the motor 3 but also as the lubricating liquid of the mechanical seal 5.

  Thus, the circulating impeller 7 for circulating the coolant is attached to the shaft 35 by using the urging force of the compression spring 53 of the mechanical seal 5. More specifically, as shown in FIGS. 4 to 6, the circulating impeller 7 includes an annular hub 71 and a plurality of (five in the illustrated example) blades 72 standing on the outer peripheral surface of the hub 71. The main body portion 73 includes a receiving portion 74 provided integrally with the hub 71 so as to spread radially inward from the lower end of the hub 71. Since the circulation impeller 7 is attached to the shaft 35 of the motor 3, it is preferable that the circulation impeller 7 is lightweight so as not to lose the rotational balance. That is, the weight reduction of the circulating impeller 7 eliminates the need for balance adjustment associated with attaching the circulating impeller 7 to the shaft 35. In order to reduce the weight, the circulating impeller 7 may be integrally formed with various synthetic resins such as polyphenylene sulfide resin (PPS).

  The hub 71 of the circulating impeller 7 has an annular shape whose diameter is larger than the outer diameter of the mechanical seal 5 as shown in an end view in FIG. In this example, the hub 71 has a length approximately the same as the length of the compression spring 53 of the mechanical seal 5, but the length of the hub 71 is not particularly limited, such as interference of other members. May be set as appropriate.

  As shown in FIG. 6 (a), each blade 72 has a predetermined wing shape in cross section and a radially outward direction from the outer peripheral surface of the hub 71 so as to have a predetermined angle of attack. It protrudes toward As a result, the circulation impeller 7 is configured as an axial-flow impeller, and, as will be described later, when attached to the shaft 35, the coolant is changed from the top to the bottom in the axial direction, in other words, the motor. It is comprised so that it may flow from the part 22 side to the pump part 21 side.

  As shown in FIGS. 6A and 6B, the receiving portion 74 has a thin plate shape and is provided at the lower end of the hub 71. Thereby, the position of the receiving part 74 and each blade | wing 72 provided in the hub 71 has shifted | deviated to the axial direction. As will be described later, the receiving portion 74 is sandwiched between the lower end of the compression spring 53 of the mechanical seal 5 and the lower rotary ring 54 (that is, the flange portion 542). For this reason, the inner diameter of the receiving portion 54 is set larger than the outer diameter of the outer insertion portion 541 of the lower rotary ring 54 of the mechanical seal. Further, a protrusion 741 protruding from the surface is formed at a predetermined circumferential position in the receiving portion 74 so as to extend in the radial direction, and this protrusion 741 is the tip of the compression spring 53 constituted by a coil spring. And the relative rotation between the compression spring 53 and the circulating impeller 7 is prevented. As a result, the circulating impeller 7 rotates together with the shaft 35 of the motor 3.

  As shown in FIGS. 4 and 5, the circulation impeller 7 is disposed between the compression spring 53 and the lower rotary ring 54, and the receiving portion 74 is provided between the lower end of the compression spring 53 and the lower rotary ring 54. It is clamped by the flange 542. That is, the circulating impeller 7 is attached to the shaft 35 so as to rotate integrally when the receiving portion 74 receives the urging force of the compression spring 53.

  In this attached state, the main body 73 of the circulating impeller 7 surrounds the outer periphery of the compression spring 53, whereby each blade 72 is located at a substantially central position in the axial direction of the mechanical seal 5. . 2 and 4, the impeller casing 62 of the partition wall member 6 is arranged so as to cover the outer periphery of each blade 72, and the circulation blade configured in an axial flow manner When the circulating impeller 7 rotates with the rotation of the shaft 35 by the wheel 7 and the impeller casing 62 of the partition wall member 6, the coolant is supplied from the motor unit 22 side to the pump unit 21 side along the shaft 35. (See the arrow in FIG. 2).

  Due to the coolant circulation structure of the pump configured as described above, the coolant is cooled between the motor casing 33 and the outer casing 36 as the shaft 35 and the circulating impeller 7 rotate as shown in FIG. The liquid flows from the liquid flow path 37 into the communication chamber 48 through the inlet 46 of the housing 4. In the communication chamber 48, the pump 22 passes through the circulating impeller 7 and the impeller casing 62 from the space on the motor unit 22 side (in other words, the inlet 46 side or the housing 4 side) separated by the partition wall 61. The coolant flows into the space on the part 21 side (in other words, on the outlet 47 side or the lid casing 242 side). Thus, the coolant flowing into the pump unit 21 returns to the coolant channel 37 through the slit 423 and the outlet 47 (see the arrow in FIG. 2). As the coolant circulates, the motor 3 in the motor casing 33 is cooled.

  In this coolant circulation structure, the circulation impeller 7 is attached and fixed to the shaft 35 of the motor 3 using the biasing force of the compression spring 53 of the mechanical seal 5, and the attachment structure of the circulation impeller 7 is extremely high. It has been simplified. Further, the circulation impeller 7 can be attached to the shaft 35 along with the attachment of the mechanical seal 5 to which the fixed ring, the rotary ring, and the compression spring are attached in order. It is also simplified.

  Compared to the conventional configuration in which the circulating impeller is attached to the shaft 35 separately from the mechanical seal 5, the mounting structure reduces the space required for mounting the circulating impeller 7 and the length of the shaft 35 of the motor 3. Can be shortened accordingly. In particular, in the above-described configuration, the main body 73 of the circulation impeller 7 is disposed so as to surround the outer periphery of the compression spring 53 of the mechanical seal 5, and the circulation impeller 7 and the mechanical seal 5 are connected to the shaft 35. Therefore, the space for attaching the circulation impeller 7 is not required in the axial direction of the shaft 35, and the length of the shaft 35 can be further shortened. This is advantageous in reducing the amount of deflection of the shaft 35 and suppressing vibration. Although the receiving portion 74 of the circulating impeller 7 is sandwiched between the compression spring 53 and the lower rotary ring 54, the receiving portion 74 has a thin plate shape and the compression spring 53 contracts, thereby mechanically. An increase in the overall length of the seal 5 can also be suppressed.

  In addition, for example, in the natural cooling specification pump in which the coolant circulation structure is omitted, the attachment of the circulation impeller 7 to the shaft 35 may be omitted, but in this case, the forced cooling specification pump is not compulsory. In the cooling specification pump, there is no space for attaching the circulation impeller 7 in the first place. Therefore, even if the attachment of the circulation impeller 7 is omitted, no empty space is generated in the axial direction of the shaft 35. This has the advantage that the design and parts of the pump including the shaft 35 can be made common regardless of the difference in the specifications of whether or not the pump has a coolant circulation structure. Further, the circulation impeller 7 is attached by the urging force of the compression spring 53, and the presence or absence of the circulation impeller 7 can be absorbed by the expansion and contraction of the compression spring 53. This is also advantageous for common use of pump parts. is there.

  The impeller casing 62 is provided with the circulating impeller 7 as an axial flow type, and the circulating impeller 7 is connected to the shaft 35 of the motor 3 so that the coolant flows from the motor portion 22 side toward the pump portion 21 side. The attachment can be advantageous in increasing the cooling efficiency of the motor 3. That is, the coolant that has received heat from the motor 3 in the motor unit 22 flows into the communication chamber 48 of the housing 4 through the inflow port 46 and is directed from the motor unit 22 side to the pump unit 21 side by the circulation impeller 7. Flowing. Then, on the pump unit 21 side, after the cover casing 242 is sandwiched between the pump handling liquid in the pump casing 24, that is, after heat exchange with a relatively low temperature liquid, the cooling liquid is slit 423. And it returns to the motor part 22 side through the outflow port 47.

  Here, the inside of the communication chamber 48 is separated by the partition wall 61 into a space on the inlet 46 side and a space on the outlet 47 side, and the both spaces are communicated only through the circulation impeller 7 and the impeller casing 62. The coolant can be efficiently circulated by the rotation of the circulation impeller 7. This can contribute to the improvement of the cooling efficiency of the motor 3.

  As the axial flow type impeller 7 causes the coolant to flow from the motor unit 22 side toward the pump unit 21 side, the coolant having a relatively high flow velocity collides with the upper surface of the lid casing 242. A turbulent coolant flow can occur near the top surface. This can increase the efficiency of heat exchange between the coolant and the liquid handled by the pump, and thus can increase the cooling efficiency of the motor 3.

  Further, since the communication chamber 48 formed in the housing 4 is partly defined by the lower surface of the upper member 41, a portion that holds the bearing 352, that is, a standing wall portion and a bottom wall that constitute the bearing holder 414. A part etc. will contact a cooling fluid directly. With this configuration, the bearing 352 can also be efficiently cooled by the coolant.

  As described above, the housing 4 is formed with the fixing portion 415 for fixing the upper fixing ring 51 of the mechanical seal 5 on the lower surface side of the upper member 41. ) Enters the bearing holder 414 through the through hole 413 of the upper member 41. At this time, a drainage hole 418 extending obliquely downward is formed at the bottom of the bearing holder 414, so that the leaked coolant is discharged to the submerged pool chamber 416 through the drainage hole 418. This effectively prevents the bearing 352 from being flooded.

  In addition, a concave portion 417 having a deeper bottom than the bearing holder 414 is formed in a part of the submerged reservoir 416, and a liquid level sensor 45 for detecting submersion is disposed in the concave portion 417. ing. Thereby, the height of the liquid level in the submerged pool chamber 416 when the water level is detected by the liquid level sensor 45 is lower than the lowermost end of the bearing 352 as indicated by a one-dot chain line in FIG. This is advantageous in that it is possible to avoid the immersion of the motor 3 as well as the bearing 352.

  Here, from the viewpoint of avoiding flooding of the bearing, it is common in the prior art to provide the flooded storage chamber at a position below the bearing holder that holds the bearing. For this reason, for example, Japanese Patent Laid-Open No. 11-294373 is proposed. As described in Japanese Laid-Open Patent Publication No. 2001-19349 and Japanese Laid-Open Patent Publication No. 2001-19349, it is conventional to form a submerged pool chamber by disposing a member different from the bearing holder below the bearing holder. Met. On the other hand, in the above-described configuration, both the bearing holder 414 and the water storage chamber 416 are formed in the housing 4, and the bearing holder 414 and the water storage chamber 416 are disposed at substantially the same position in the axial direction. By forming the drain hole 418 communicating with the bearing holder 414 and the submerged reservoir chamber 416, it is possible to reduce the number of parts while avoiding the submersion of the bearing 352. In addition, the formation of the recessed portion 417 in the submerged reservoir chamber 416 is advantageous in avoiding the flooding of the bearing 352 more reliably. Further, the formation of the bearing holder 414 and the submerged pool chamber 416 in one member, that is, the housing 4, enables the housing 4 to be in direct contact with the cooling liquid as described above, thereby cooling the bearing 352. Will also be advantageous.

  The lid member 44 is attached to the upper end of the upper member 41 to isolate the submerged pool chamber 416 from the motor casing 33, which is advantageous for reliably avoiding the entry of water into the motor casing 33. That is, in this submersible pump 1, the liquid that can be stored in the submerged reservoir 416 is a coolant mainly composed of water, and when the lid member 44 is omitted, when the coolant is stored in the submerged reservoir 416, The heat generated by driving the motor 3 evaporates the coolant, and moisture enters the motor casing 33. Moisture that has entered the motor casing 33 adheres to the windings of the motor 3 as water droplets when the temperature in the motor casing 33 decreases due to the stop of the motor 3, which may cause, for example, insulation breakdown. On the other hand, attaching the lid member 44 and isolating the submerged reservoir chamber 416 from the motor casing 33 is an advantageous configuration in that such a problem can be surely avoided. In this configuration, since the submerged reservoir chamber 416 is also in contact with the coolant passage, evaporation of the coolant stored in the submerged reservoir chamber 416 itself can be suppressed.

  Further, by using the lid member 44 also as a presser for the bearing 352, it is advantageous in reducing the number of parts, and the parts by forming the bearing holder 414 and the submersion chamber 416 in the housing 4 as described above. Combined with this, it is possible to greatly reduce the number of parts and simplify the assembly process accompanying the simplification of the structure.

  In the above configuration, the mechanical seal 5 is configured as a monocoil spring type mechanical seal having a single compression spring that is externally attached to the shaft 35. For example, a small-diameter compression spring is used as the outer periphery of the shaft 35. The circulation impeller 7 may be attached to a plurality of multi-spring type mechanical seals arranged along the axis. In this case, the receiving portion 74 of the circulating impeller 7 may be sandwiched between, for example, the flange portion 542 of the lower rotary ring 54 by a plurality of compression springs. In this case, if necessary, the front end portions of a plurality of compression springs may be connected to each other, and a contact member that contacts the receiving portion 74 of the circulating impeller 7 may be further attached.

  The circulation impeller 7 is not limited to being disposed between the compression spring 53 and the lower rotary ring 54 but may be disposed between the compression spring 53 and the upper rotary ring 52. In that case, the top and bottom of the circulating impeller 7 shown in FIGS. 4 and 5 may be reversed and placed between the compression spring 53 and the upper rotary ring 51. If the setting is made from the motor unit 22 side to the pump unit 21 side, the direction of each blade 72 also needs to be reversed.

  Further, the circulation impeller 7 may be arranged in two stages by being arranged between the compression spring 53 and the lower rotary ring 54 and between the compression spring 53 and the upper rotary ring 52.

  In the above example, the mechanical seal 5 presses and urges the two upper and lower rotating rings 52 and 54 by one compression spring 53, but the compression spring and the lower rotating ring press and urge the upper rotating ring. The compression spring that presses and urges may be configured by different compression springs. Also in this case, the arrangement of the circulating impeller 7 may be any of the upper side, the lower side, and the upper and lower sides of the mechanical seal.

  The flow direction of the coolant by the circulating impeller 7 is not limited from the motor unit 22 side to the pump unit 21 side, and may be in the opposite direction. The circulating impeller is not limited to the axial flow type, and may be a centrifugal type or a diagonal flow type. In that case, what is necessary is just to set the shape of an impeller casing suitably so that it may respond | correspond to the form of a circulating impeller. In some cases, the impeller casing may be omitted.

  Although the partition member 6 separate from the housing 4 is attached and fixed to the housing 4, a portion having the same function as the partition member 6 may be formed integrally with the housing 4.

  The circulating impeller 7 may also be formed integrally with the rotating ring of the mechanical seal 5. In this case, the assembly of the mechanical seal 5 and the attachment of the circulating impeller 7 can be further simplified. On the other hand, as described above, in order to share parts for the difference in specifications between the forced cooling specification with the coolant circulation structure and the natural cooling specification without the coolant circulation structure, It is desirable that the car and the rotating ring are separate bodies.

  Further, the coolant circulation structure disclosed herein is not limited to application to a submersible pump.

  As described above, the cooling liquid circulation structure of the pump disclosed herein simplifies the mounting structure by attaching the circulating impeller for circulating the cooling liquid to the motor shaft using the compression spring of the mechanical seal. In addition, it is useful in that the shaft length can be made as short as possible.

1 Submersible pump (pump)
21 Pump part 22 Motor part 23 Impeller 3 Motor 33 Motor casing 35 Shaft 36 Outer casing 37 Coolant flow path 4 Housing 46 Inlet 47 Outlet 48 Communication chamber 5 Mechanical seal 51 Upper fixed ring 52 Upper rotary ring 53 Compression spring 54 Lower rotary ring 55 Lower fixed ring 6 Bulkhead member 61 Bulkhead 62 Impeller casing 7 Circulating impeller 72 Blade 73 Main body 74 Receiving part

Claims (4)

A pump unit including an impeller;
A motor part including a motor extending in a predetermined axial direction and connected to the impeller, and driving the impeller through the shaft;
A mechanical seal disposed between the pump part and the motor part and sealing the shaft;
A coolant circulation channel for cooling the motor by circulating coolant between the motor unit side and the pump unit side,
The mechanical seal includes at least a rotary ring fixed to the shaft, a fixed ring attached to the pump housing side, and a compression spring that presses the rotary ring and the fixed ring against each other in the axial direction by an urging force thereof,
A circulation impeller that circulates the coolant in the coolant circulation channel by being attached to the shaft and rotating together with the shaft further comprises:
The circulating impeller is a coolant circulation structure of a pump attached to the shaft so as to rotate together with the shaft by an urging force of the compression spring of the mechanical seal. In the coolant circulation structure of the pump according to claim 1,
The circulation impeller includes a ring-shaped main body portion in which a plurality of blades are arranged in the circumferential direction, a receiving portion that is provided integrally with the main body portion, and receives a biasing force of the compression spring; Have
The circulating impeller is attached to the shaft by the receiving portion being sandwiched between the end of the compression spring and the rotating ring,
The main body is a coolant circulation structure of a pump that is disposed at a position overlapping the mechanical seal in the axial direction on the outer periphery of the mechanical seal. In the cooling liquid circulation structure of the pump according to claim 1 or 2,
The motor part is
A motor casing that houses the motor;
An outer which is arranged at a predetermined interval with respect to the outer peripheral surface of the motor casing and forms a circumferential flow path which forms a part of the coolant circulation flow path with the outer peripheral surface of the motor casing. A casing,
A housing that is attached to a lower end opening of the motor casing and the outer casing and through which the shaft is disposed, and
Each of the housings opens into the circumferential channel, and has an inlet through which the coolant flows from the circumferential channel, an outlet from which the coolant flows into the circumferential channel, and the flow The inlet and the outlet are in communication with each other, and a part of the coolant is circulated by the pump unit, thereby forming a part of the coolant circulation channel.
The mechanical seal is attached to the shaft in the communication chamber, whereby the circulation impeller is disposed in the communication chamber,
The circulation impeller is an axial flow type, and a coolant circulation structure of a pump attached to the shaft so as to flow the coolant along the axial direction from the motor unit side toward the pump unit side . In the cooling liquid circulation structure of the pump according to claim 3,
The motor unit further includes a partition member attached to the housing,
The partition member surrounds the outer periphery of the axial-flow circulation impeller, and partitions the communication chamber into the inlet-side space and the outlet-side space, and the inlet-side space; A pump coolant circulation structure including an impeller casing that communicates the space on the outlet side with each other.

Images