JP5159371B2 - Shaft seal device and electric pump provided with the same - Google Patents

Description

  The present invention relates to a shaft seal device in an electric pump, for example.

  Conventionally, as a shaft seal device for a rotary shaft in an electric pump, a mechanical seal is arranged on the outer periphery of the rotary shaft in an oil chamber partitioned by two casings facing each other in the vertical direction, whereby the upper and lower casings are arranged. There is known an apparatus that seals between the rotary shaft and the rotary shaft.

  However, in such a shaft seal device, the mechanical seal rotates with the rotation of the rotating shaft, whereby a swirling flow of the lubricating oil is generated, and the lubricating oil is pushed outward in the radial direction. As a result, the liquid level of the lubricating oil in the vicinity of the rotating shaft is lowered, and there is a problem that the lubrication of the upper sliding portion of the mechanical seal that seals between the upper casing and the rotating shaft is deteriorated.

Therefore, by arranging an annular wall body that surrounds the entire outer periphery of the mechanical seal, the annular wall body prevents the lubricating oil from being pushed outward in the radial direction even when the rotary shaft rotates. A technique for ensuring lubrication of an upper sliding portion in a mechanical seal is known (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 11-37301

  However, the shaft seal device described in the above-mentioned patent document has a configuration in which an annular wall body is separately prepared and fixed to each of the upper casing and the lower casing, so that the number of parts increases. In addition to the attachment of the mechanical seal, it is necessary to attach an annular wall body, resulting in an increase in the number of attachment steps.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a shaft seal device with reduced manufacturing costs by reducing the number of parts and the accompanying man-hours, and the shaft seal device. It is to provide an electric pump.

  According to one aspect of the present invention, the shaft seal device is disposed relative to the upper casing, the upper casing including a partition upper surface that partitions the upper surface of the oil chamber filled with lubricating oil, and the oil chamber. A lower casing including a lower section defining a lower surface; a rotating shaft that rotates around an axis extending in the vertical direction; and that is disposed through the upper and lower casings; and A mechanical seal that is disposed around the outer periphery and seals between the upper and lower casings and the rotating shaft, and the upper casing projects downward from the upper surface of the compartment, and the mechanical seal A halved upper standing wall that is curved so as to surround the outer periphery of the lower casing is integrally formed, and the lower casing protrudes upward from the lower surface of the compartment, and the rotation On the opposite side of the upper standing wall across the wall, a halved lower standing wall curved so as to surround the outer periphery of the mechanical seal is integrally formed, and the upper standing wall and the lower standing wall substantially An annular wall that surrounds the entire outer periphery of the mechanical seal is formed, and the upper standing wall is provided with a predetermined gap with respect to the lower surface of the compartment of the lower casing, while the lower standing wall is A predetermined gap is provided with respect to the partition upper surface of the upper casing.

  According to this configuration, the annular wall in the oil chamber is constituted by the upper standing wall formed integrally with the upper casing and the lower standing wall formed integrally with the lower casing. Since the annular wall substantially surrounds the entire outer circumference of the mechanical seal, the lubricating oil is prevented from being pushed outward in the radial direction when the rotating shaft rotates.

  The upper standing wall is provided with a predetermined gap with respect to the lower surface of the compartment of the lower casing, while the lower standing wall is provided with a predetermined gap with respect to the upper surface of the upper casing. Therefore, along with the rotation of the mechanical seal, the lubricating oil flows into the annular wall from the gap between the upper vertical wall and the lower section of the lower casing and from the gap between the lower vertical wall and the upper section of the upper casing to the outside of the annular wall. To leak. That is, the lubricating oil flows from the lower part of the annular wall and flows out from the upper part. By such a flow of the lubricating oil, the lubricating oil is sufficiently supplied not only to the lower sliding portion of the mechanical seal but also to the upper sliding portion, and this portion is also well lubricated.

  And in this structure, since the upper standing wall and the lower standing wall which comprise an annular wall are each integrally formed in the upper casing and the lower casing, it is the structure which makes the conventional annular wall a separate body. In comparison, the number of parts is reduced. In addition, since the annular wall is completed by assembling the upper casing and the lower casing together, the number of mounting steps can be reduced. As a result, the manufacturing cost is reduced.

  Opposite ends facing each other in the circumferential direction in the upper standing wall and the lower standing wall are arranged so as to be displaced in the radial direction, and thereby, between the opposing ends in the upper standing wall and the lower standing wall, A slit that communicates the inside and the outside may be formed, and the slit may open toward the outside of the annular wall so as to face the rotation direction of the rotation shaft.

  Since the slit between the upper vertical wall and the lower vertical wall opens toward the outside of the annular wall so as to oppose the rotational direction of the rotary shaft, the lubricating oil enters the annular wall through the slit as the rotary shaft rotates. Is more likely to be inhaled. On the other hand, it is difficult for the lubricating oil in the annular wall to flow out of the annular wall through this slit. Accordingly, the lubricating oil flows out from the inside of the annular wall to the outside through the upper gap, and in particular, lubrication to the sliding portion at the upper part of the mechanical seal is improved.

  According to another aspect of the present invention, the electric pump is disposed above the shaft sealing device, below the lower casing, above the impeller attached to the rotary shaft, and above the upper casing. And a motor that rotationally drives the impeller via the rotating shaft.

  As described above, according to the present invention, the upper standing wall and the lower standing wall constituting the annular wall are formed integrally with the upper casing and the lower casing, respectively, so that the conventional annular wall is separated. Compared to the configuration, the number of parts can be reduced and the number of mounting steps can be reduced. As a result, for example, the manufacturing cost of the electric pump can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a submersible pump 1 including a shaft seal device according to an embodiment of the present invention. The submersible pump 1 includes a pump unit 21 having an impeller 25 and a motor unit 22 having a motor 3 that drives the impeller 25. The submersible pump 1 is configured such that the pump unit 21 and the motor unit 22 are arranged side by side in the vertical direction by disposing the pump unit 21 on the lower side of the oil casing 23 and the motor unit 22 on the upper side. ing. The submersible pump 1 is a lightweight type in which a later-described head cover 34 and pump casing 24 are formed of a predetermined resin material.

  The motor unit 22 includes the motor 3 including a stator 31 and a rotor 32, a stator casing 33 that covers the stator 31 of the motor 3, and a head cover 34 that is attached to the upper end of the stator casing 33. The rotation shaft 35 of the motor 3 is arranged extending in the vertical direction.

  The stator casing 33 is formed in a substantially cylindrical shape with openings at both ends. The upper end opening of the stator casing 33 is closed by a motor cover 36, and a bearing 35 a that rotatably supports the upper end portion of the rotating shaft 35 is attached to the lower surface of the motor cover 36.

  The head cover 34 is attached to the upper end of the stator casing 33. The head cover 34 includes an upper wall and a peripheral wall that extends downward from the peripheral edge of the upper wall and is fixed to the upper end of the stator casing 33, and has a cross-sectional shape formed in an inverted U shape. As a result, the head cover 34 forms an accommodation space 34 a for accommodating various electrical components together with the motor cover 36. A cable boot through which a power supply cable for supplying power to the motor 3 is inserted is attached to the upper wall of the head cover 34, and a handle 34b is attached to the center of the upper surface thereof.

  The head cover 34 is fixed to the oil casing 23 by a plurality of bolts 37 (only one is shown in the figure) arranged at predetermined intervals in the circumferential direction. In other words, the bolt 37 that has passed through the through hole formed in the peripheral edge of the head cover 34 passes through the motor cover 36 and extends downward along the inner peripheral surface of the stator casing 33, so that the peripheral edge of the oil casing 23. It is screwed to the part. Thus, in this submersible pump 1, the head cover 34, the stator casing 33, and the motor cover 36 are fixed to the oil casing 23 at once by the long bolts 37 extending in the vertical direction. In this submersible pump 1, the number of parts and the number of assembling steps are reduced.

  The oil casing 23 is attached to the lower end of the stator casing 33, and the lower end opening of the stator casing 33 is closed by the oil casing 23.

  The oil casing 23 is a casing that forms an oil chamber 4 filled with lubricating oil together with the pump casing 24 by attaching a pump casing 24 to the lower side of the oil casing 23. A through-hole 23a to be inserted is formed (see FIG. 2), and a bearing 35b that rotatably supports an intermediate portion of the rotary shaft 35 is attached to the upper surface thereof.

  In the oil chamber 4 defined by the oil casing 23 and the pump casing 24, the rotary shaft 35 is sealed with a mechanical seal 5. An annular wall 6 is provided in the oil chamber 4 so as to surround substantially the entire outer periphery of the mechanical seal 5. Details of the configuration in the oil chamber 4 will be described later.

  The pump unit 21 includes an impeller 25 attached to the lower end of the rotation shaft 35 of the motor 3 and a pump casing 24.

  The submersible pump 1 is a centrifugal pump, and the pump casing 24 is formed by integrating the upper first pump casing and the lower second pump casing, which together with the oil casing 23 form the oil chamber 4, It is configured. A through hole 24a into which the rotary shaft 35 is inserted is formed in the upper part of the pump casing 24 (see FIG. 2), and a volute chamber 26 for accommodating the impeller 25 is formed therein.

  Moreover, the lower part of the pump casing 24 is opened downward, and the support part 27 which has the opening 27a for supporting the lower end part of the impeller 25 is attached to this opening.

  On the other hand, a discharge portion 28 that protrudes laterally and bends upward is integrally formed on the side portion of the pump casing 24. The discharge portion 28 communicates with the spiral chamber 26 and is formed with a discharge port 28a that opens upward. The discharge port 28a is connected to a discharge pipe (not shown).

  In this embodiment, the impeller 25 is a non-clog type impeller, and a boss portion to which the lower end portion of the rotating shaft 35 is fixed is provided at the center of the upper end surface.

  The impeller 25 has an inlet 25a that opens downward at the lower end surface, and an outlet 25b that opens sideways at the peripheral surface. Further, an inner flow path 25c extending in the axial direction while rotating around the rotation shaft 35 is formed inside the impeller 25, and the inlet 25a and the outlet 25b are connected to each other by the internal flow path 25c. .

  On the outer peripheral surface of the impeller 25, an external flow path 25d that is recessed inward in the radial direction is formed. The external flow path 25d is not a flow path extending in the rotation axis direction, and the flow path center is located on an orthogonal plane orthogonal to the rotation axis 35 of the impeller 25. The external flow path 25d is continuous with the downstream side of the internal flow path 25c at the outlet 25b. The external flow path 25d circulates over a length of at least half the circumference of the impeller 25.

  This external flow path 25d is partitioned by blades 25e. The blade 25e is a so-called radial flow blade (centrifugal blade), and the centrifugal blade 25e boosts the water in the external flow path 25d and discharges the water outward (radially outward).

  In the impeller 25, a first flange portion 25f that protrudes laterally over the entire circumference is formed above the external flow path 25d. Further, a second flange portion 25g that protrudes laterally over the entire circumference is formed below the external flow path 25d. The second flange portion 25g vertically partitions the lower portion of the impeller 25 where the inlet 25a is formed and the upper portion where the outlet 25b is formed. That is, the impeller 25 is a closed-type impeller in which the inlet 25a and the outlet 25b are partitioned by the second flange portion 25g.

  Next, the configuration in the oil chamber 4 will be described in detail with reference to FIG. The mechanical seal 5 is relatively disposed on the rotary shaft 35 with respect to the upper mating ring 51 fitted into the fitting portion 23c provided so as to surround the through hole 23a on the lower surface (partition upper surface 23b) of the oil casing 23. An upper seal ring 52 fixed at the upper position, and a lower mating ring 53 fitted into a fitting portion 24c provided so as to surround the through hole 24a on the upper surface (partition lower surface 24b) of the pump casing 24; The lower seal ring 54 fixed at a relatively lower position on the rotary shaft 35 and the upper seal ring 52 and the lower seal ring 54 are disposed between the upper seal ring 52 and the upper mating ring 51. A coil spring 55 for pressing and urging the lower seal ring 54 toward the lower mating ring 53; It is configured to include a. Thus, in the mechanical seal 5, when the rotary shaft 35 is rotating, the upper seal ring 52 and the upper mating ring 51 slide, and the lower seal ring 54 and the lower mating ring 53 slide. However, relative rotation will occur.

  As shown in FIGS. 2 to 4, the partition upper surface 23 b of the oil casing 23 has a halved upper standing wall 61 that protrudes downward and is curved in an arc shape so as to surround the outer periphery of the mechanical seal 5. It is integrally formed. As shown in FIG. 2, when the pump casing 24 is assembled to the oil casing 23, the lower end of the upper vertical wall 61 forms a predetermined gap with respect to the upper surface (partition lower surface 24b) of the pump casing 24. Is set to Further, as shown in FIG. 3, the one end portion 61 a in the circumferential direction of the upper standing wall 61 is bent outward in the radial direction so that the diameter thereof is enlarged, and as described later, One end portion 62a in the circumferential direction of the lower standing wall 62 and the one end portion 61a in the circumferential direction of the upper standing wall 61 that are integrally formed on the partition lower surface 24b of the pump casing 24 are shifted in the radial direction. (See FIG. 5).

  As shown in FIGS. 2, 5, and 6, the partition casing lower surface 24 b of the pump casing 24 protrudes upward and has a halved lower side curved in an arc shape so as to surround the outer periphery of the mechanical seal 5. The standing wall 62 is integrally formed. As shown in FIG. 2, when the pump casing 24 is assembled to the oil casing 23, the upper end of the lower vertical wall 62 is formed with a predetermined gap with respect to the partition upper surface 23b of the oil casing 23. Is set. Further, as shown in FIG. 5, the lower vertical wall 62 is disposed so as to surround the outer periphery of the mechanical seal 5 on the side opposite to the upper vertical wall 61 across the rotation shaft 35. In FIG. 5, the arrangement of the upper standing wall 61 in a state where the oil casing 23 and the pump casing 24 are assembled to each other is virtually shown. In other words, the annular wall 6 is formed by the upper standing wall 61 and the lower standing wall 62, and the entire circumference of the mechanical seal 5 is surrounded by the annular wall 6. Further, the other end portion 62b in the circumferential direction of the lower standing wall 62 is bent outward in the radial direction so that its diameter is enlarged. As a result, the other end portion 62b in the circumferential direction of the lower standing wall 62 and the other end portion 61b in the circumferential direction of the upper standing wall 61 are displaced in the radial direction. In this way, slits 63 are formed in two portions of the substantially annular ring wall 6 facing each other in the diametrical direction, with the ends of the upper standing wall 61 and the lower standing wall 62 being shifted from each other. The slit 63 is opened facing the rotation direction of the rotary shaft 35 indicated by an arrow in FIG. 5, and the inside and outside of the annular wall 6 communicate with each other through the slit 63.

  With such a configuration in the oil chamber 4, when the rotating shaft 35 rotates, a swirling flow of the lubricating oil is generated with the rotation of the mechanical seal 5. At this time, since the annular wall 6 substantially surrounds the entire circumference of the mechanical seal 5, the annular wall 6 prevents the lubricating oil from escaping radially outward. Further, the lubricating oil flows into the annular wall 6 through the two slits 63 and 63 by the swirling flow of the lubricating oil (see the arrow in FIG. 5), and the lubricating oil comes from below with the rotation of the coil spring 55 of the mechanical seal 5. By flowing upward, the lubricating oil flows into the annular wall 6 through the gap between the upper standing wall 61 and the partition lower surface 24b, and flows out of the annular wall 6 through the gap between the lower standing wall 62 and the partition upper surface 23b. (See arrow in FIG. 2). Thus, the lubricating oil can be sufficiently supplied also to the upper sliding portion of the mechanical seal 5.

  In this submersible pump 1, the annular wall 6 surrounding the outer periphery of the mechanical seal 5 is configured by two halved standing walls 61 and 62, and one of the standing walls 61 is used as the oil casing 23, and the other standing wall 62 is used. Are integrally provided in the pump casing 24. For this reason, the number of parts can be reduced. At the same time, in this halved configuration, as indicated by an arrow in FIG. 2, the lubricating oil flows into the annular wall 6 from the lower side while the lubricating oil flows out from the upper side. Can be easily realized. For this reason, it is possible to satisfactorily lubricate the sliding portion on the upper part of the mechanical seal 5 that is likely to cause a problem in terms of lubricity.

  Further, as the rotating shaft 35 rotates, the lubricating oil flows in the clockwise direction in FIG. 5. However, since the two slits 63 are opened facing the rotating direction of the rotating shaft 35, the lubricating oil Efficiently flows into the annular wall 6 through the slit 63, and the lubricating oil hardly flows out of the annular wall 6 through the slit 63. Thus, the lubricating oil in the annular wall 6 can be made to flow well, and the lubricating oil in the annular wall 6 can be discharged to the outside of the annular wall 6 after being supplied to the upper part of the mechanical seal 5. Lubrication to the sliding part on the upper part of the seal 5 becomes even better.

  Moreover, since the annular wall 6 is completed only by assembling the oil casing 23 and the pump casing 24 to each other, the number of assembling steps can be reduced. As a result, the manufacturing cost can be reduced in combination with the reduction in the number of parts.

  The configuration of the annular wall 6 is not limited to the configuration shown in FIG. 5, but may be as shown in FIG. That is, the both ends 61a and 61b of the upper standing wall 61 are bent outward in the radial direction so that the diameter is increased, while the both ends 62a and 62b of the lower standing wall 62 are not bent. May be. Although not shown, contrary to FIG. 7, the both ends 62 a and 62 b of the lower standing wall 62 are bent outward in the radial direction so that the diameter increases, while the upper standing wall 61 is bent. Both end portions 61a and 61b may not be bent.

  However, in such a configuration, one of the two slits 63, 63 opens relative to the rotation direction of the rotation shaft 35, while the other slit 63 opens along the rotation direction of the rotation shaft 35. Therefore, it is inferior to the configuration shown in FIG. 5 from the viewpoint of efficient inflow of the lubricating oil into the annular wall 6 and from the viewpoint of preventing the lubricating oil in the annular wall 6 from flowing out from the slit 63. Become.

  Further, as shown in FIG. 5, in the above-described embodiment, the end portions 61 a and 61 b of the upper standing wall 61 and the end portions 62 a and 62 b of the lower standing wall 62 are arranged so as to partially overlap in the radial direction. However, the present invention is not limited to this. For example, each end of the upper standing wall 61 is arranged so that the end portions 61a and 61b of the upper standing wall 61 and the end portions 62a and 62b of the lower standing wall 62 do not overlap in the radial direction. The portions 61a and 61b and the end portions 62a and 62b of the lower standing wall 62 may be arranged with a predetermined gap in the circumferential direction.

  Further, although not shown in the drawings, the end portions 61a and 61b of the upper standing wall 61 and the end portions 62a and 62b of the lower standing wall 62 are arranged to contact each other so that the slit 63 is not formed. May be. However, the configuration in which the slit 63 is formed as in the above-described embodiment has an advantage that it is advantageous in terms of dimensional tolerance in addition to the advantage that the lubricating oil can be efficiently flowed into the annular wall 6. .

  The configuration of the pump unit 21 is not limited to the configuration including the non-clog type impeller 25 described above. The impeller may not be a so-called non-clog type impeller, and may be, for example, a multiblade centrifugal impeller.

  As described above, the present invention can improve the lubrication of the mechanical seal while reducing the manufacturing cost by reducing the number of parts and the like. Therefore, the shaft seal device and the electric pump having such a mechanical seal lubrication structure are provided. Useful for.

It is an electric pump longitudinal cross-sectional view which concerns on embodiment of this invention. It is a longitudinal cross-sectional explanatory drawing which expands and shows the structure of the oil chamber vicinity. It is a bottom view of an oil casing. It is IV-IV sectional drawing of FIG. It is a top view of a pump casing. It is VI-VI sectional drawing of FIG. It is a FIG. 6 corresponding view which shows the structure of the annular wall which concerns on other embodiment.

Explanation of symbols

1 Submersible pump (electric pump)
23 Oil casing (upper casing)
23b Compartment upper surface 24 Pump casing (lower casing)
24b Division lower surface 25 Impeller 3 Motor 35 Rotating shaft 4 Oil chamber 5 Mechanical seal 6 Annular wall 61 Upper vertical wall 61a, 61b End of upper vertical wall (opposing end)
62 Lower Standing Walls 62a, 62b Ends of Lower Standing Walls (opposite ends)
63 slits

Claims (3)

An upper casing including an upper surface of a partition that defines an upper surface of an oil chamber filled with lubricating oil;
A lower casing that is disposed relative to the upper casing and includes a partition lower surface that defines a lower surface of the oil chamber;
A rotating shaft that rotates about an axis extending in the vertical direction and is disposed through the upper and lower casings;
A mechanical seal that is disposed on the outer periphery of the rotary shaft in the oil chamber and seals between the upper and lower casings and the rotary shaft, respectively.
The upper casing is integrally formed with a halved upper standing wall that protrudes downward from the upper surface of the compartment and is curved so as to surround the outer periphery of the mechanical seal.
The lower casing protrudes upward from the lower surface of the partition, and on the side opposite to the upper standing wall sandwiching the rotating shaft, the lower half of the half-like shape curved so as to surround the outer periphery of the mechanical seal The standing wall is integrally formed,
An annular wall that substantially surrounds the entire outer periphery of the mechanical seal is formed by the upper standing wall and the lower standing wall,
The upper standing wall is provided with a predetermined gap with respect to the partition lower surface of the lower casing, while the lower standing wall is provided with a predetermined gap with respect to the partition upper surface of the upper casing. and,
As the mechanical seal rotates, the lubricating oil flows into the annular wall through a gap between the upper vertical wall and the lower section of the lower casing, and a gap between the lower vertical wall and the upper section of the upper casing. The shaft seal device is configured such that the lubricating oil flows through the annular wall from the bottom to the top so that the lubricating oil flows out of the annular wall . The shaft seal device according to claim 1,
Opposite ends facing each other in the circumferential direction in the upper standing wall and the lower standing wall are arranged so as to be displaced in the radial direction, and thereby, between the opposing ends in the upper standing wall and the lower standing wall, A slit that connects the outside and the inside is formed,
The said shaft is a shaft seal apparatus opened so that it might oppose the rotation direction of the said rotating shaft toward the outer side of the said annular wall. A shaft seal device according to claim 1 or 2,
An impeller attached to the rotating shaft, below the lower casing;
An electric pump provided with a motor that is disposed above the upper casing and that rotates the impeller via the rotating shaft.

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