JP2003003984A - Canned pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently circulate a fluid between an inner space of a can and a pump chamber. SOLUTION: This pump is provided with a stator fixed to a motor case, a rotor of which the shaft penetrated through a rotor main body is supported rotatably to the motor case, the cylindrical can be connected water-tightly to a case front wall and a case rear wall of the motor case to partition the stator and the rotor therebetween, a washer fit around a case front wall side in the shaft to regulate axis-directional motion, and the pump chamber formed adjacently to the case front wall to contain impellers attached to a front end of the shaft in its inside, and a circulation passage is formed to circulate the fluid between the inner space of the can and the pump chamber, in the pump. The rotor main body has a fluid passage formed penetratedly along an axial direction, and the washer is provided with a radial-directional flow forming means for imparting a radial-directional flow to the fluid sucked from the fluid passage in accompaniment to rotation of the rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a can arranged in a motor for rotating an impeller of a pump chamber so as to partition a stator and a rotor, and a fluid in the pump chamber The present invention relates to a canned pump configured to allow entry into an internal space partitioned by a can in a motor.

[0002]

2. Description of the Related Art Conventionally, as a pump having a simple structure for household fluid appliances, a rotary shaft of a motor for rotating an impeller and a rotary shaft of the impeller are formed by a single shaft. In some cases, a pump chamber containing an impeller attached to the tip is arranged adjacent to the motor.

In such a pump, in general, a packing box, an oil seal, or a bearing box is provided in the bearing so that the fluid in the pump chamber does not flow into the motor from the bearing that rotatably supports the shaft. It is necessary to equip a so-called shaft seal device such as a mechanical seal. However, since such a shaft sealing device performs a shaft sealing action by a seal member that is constantly in frictional contact with the shaft, maintenance such as periodical replacement of the seal member is required, and the responsibility of such maintenance is generally considered. It is virtually difficult to ask the consumer.

Therefore, by providing a casing (sealing with a can) in a region of the motor that allows the inflow of fluid from the pump chamber, the fluid flowing from the pump chamber is prevented from leaking to the outside of the can. A canned pump that does not require the shaft sealing device described above has been proposed.

An example of this type of conventional canned pump is shown in FIG. As shown in FIG. 1, the canned pump 100 includes a motor case 1 that forms the exterior of the motor, a stator 2 fixed to the inner wall of the motor case 1, a rotor body 131, and a shaft 132 that penetrates the rotor body 131. And a front end portion and a rear end portion of the shaft 132 on the case front wall 1 of the motor case 1.
1 and the case rear wall 12 have front slide bearings 5a, respectively.
And it is rotatably supported via the rear slide bearing 5b. The can 4 is arranged so as to partition between the stator 2 and the rotor 103, and the front end portion thereof is the front wall 11 of the case.
Further, the rear ends are watertightly connected to the case rear wall 12, respectively. The shaft 132 of the rotor 103 has a washer 106 for restricting axial movement of the rotor 103.
Is fitted between the rotor body 131 and the front slide bearing 5a.

The stator 2 is a member that forms the field of the motor, and includes a field core 2a made of mild steel or the like.
A coil-shaped field winding 2b formed by winding a conducting wire. The surface of the field winding 2b is entirely covered with an insulating material such as insulating paper, cotton tape or glass tape, and is insulated from the field core 2a.

On the other hand, the rotor body 131 is a member forming an armature of a motor, and is provided with an armature core 131a made of stainless steel or the like, and an armature winding for generating an induced electromotive force. . As the armature winding, for example, a cage winding is adopted, and copper rods are embedded in a plurality of groove-shaped slots formed on the peripheral surface of the armature iron wire 131a or in the vicinity thereof, and both ends thereof are formed in an annular shape. Copper end ring 31b ₂
It is formed by connecting to.

An impeller 7 arranged in a pump chamber 70 adjacent to the case front wall 11 of the motor case is attached to the tip of the shaft 132 of the rotor 103.

In the canned pump 100 having such a structure, the fluid from the pump chamber 70 is used as the can 4 in the motor.
Is allowed to flow into the interior space of the. Rotor 103
Rotates in the fluid thus filled in the can 4, thus eliminating the need for a shaft sealing device for the shaft 132.
On the other hand, since the stator 2 is separated from the fluid filled in the can 4 by the can 4, it is possible to effectively prevent the electric circuit in the motor from being short-circuited.

Also, the shaft 132 and the front slide bearing 5
The fluid from the pump chamber 70 also flows into the can 4 from the clearance set between the a and the a, and this fluid functions as a shaft lubricating liquid for the shaft 132.

By the way, there is no problem when the internal space of the can 4 is always filled with only the fluid, but when bubbles enter the internal space of the can 4 due to cavitation due to rotation of the impeller 7, for example. , Cause various problems. That is, once air bubbles enter the space surrounded by the can 4, they cannot easily escape to the outside, and the shaft 132 and the front slide bearing 5
The function of the fluid between "a" and "a" as a shaft lubricating fluid is deteriorated.

Therefore, in order to solve the problem caused by the retention of bubbles in the inner space of the can, measures have been conventionally taken to positively discharge the bubbles that have entered the can 4. .

The first is to provide a circulation passage 8 through which fluid flows inside and outside the case front wall 11 and utilize the pressure difference generated by the rotation of the impeller 7 to make the case front wall 1
The purpose is to positively circulate the fluid inside and outside 1. That is, as shown in FIG. 9, the circulation passage 8 has an outflow passage 82 penetrating on the center side of the case front wall 11 and an inflow passage 81 penetrating on the radially outer side of the outflow passage 82. It is composed of Further, the hub portion of the impeller 7 is formed with a through hole 71b that can communicate with the outflow passage 82 and reach the inside of the suction port 72a of the impeller 7. As a result, the suction negative pressure due to the rotation of the impeller 7 positively discharges the fluid in the internal space of the can 4 through the outflow passage 82, while the amount of fluid that compensates for the discharged fluid amount passes through the inflow passage 81. Enter the inner space of the can 4. By such fluid circulation, bubbles existing near the case front wall 11 or in the space S ₂ between the case front wall 11 and the rotor body 131 are positively discharged to the outside.

Second, the fluid near the rear wall 12 of the case is positively discharged by utilizing the negative suction pressure of the pump 100. That is, as shown in FIG. 9, a cap 190 with a hole is attached to the through hole 12a ₁ of the case rear wall 12, and the rear slide bearing 5 is attached to the case rear wall 12.
A small chamber R ₁ surrounding the rear end of the shaft 132 protruding to the outside via b is provided, and this small chamber and the suction side of the pump chamber are connected by a pipe 191. Since the rear slide bearing 5b utilizes the lubricating action of the liquid film, there is a predetermined clearance with the shaft 132. Therefore,
Through this clearance, the inner space of the can 4 and the small chamber R
Fluid communication with ₁ is possible. As a result, pump 1
00, the suction negative pressure applied to the small chamber R ₁ via the conduit 191 positively causes the fluid inside the case rear wall 12 to pass through the clearance between the shaft 132 and the rear slide bearing 5b. Eject, at the same time, the case rear wall 1
The bubbles existing in the vicinity of 2 or in the space S ₁ between the case rear wall 12 and the rotor body 131 are discharged. The amount of fluid corresponding to the amount of fluid discharged at this time is filled by the fluid inflow from the inflow passage 81 of the case front wall 11.

FIG. 10 shows another example of a conventional canned pump. In the canned pump 200 shown in the same figure, like the canned pump 100 shown in FIG.
Although the first and second measures are taken to positively discharge the air bubbles that have entered the can 4, the canned pump 200 shown in the same drawing is different from the canned pump 100 shown in FIG. They differ in the following points.

That is, the canned pump 1 shown in FIG.
In 00, the above small room R₁And the suction side of the pump chamber 70
By connecting and with the external pipe line 191, the case rear wall
Although the fluid around 12 is actively discharged,
In the canned pump 200 shown in FIG.
The shaft 232 is provided with an axial through hole 291 so that the small chamber R ₁
And the suction port 72a of the impeller 7 are communicated with each other. Po
The suction negative pressure of the pump 200 is applied to the through hole 29 of the shaft 232.
Small room R through 1₁Acts on the back wall of the case
The fluid inside 12 to the shaft 232 and the rear slide bearing 5
It is positively discharged through the clearance with b.

[0017]

However, the conventional canned pump 100 shown in FIG. 9 and the conventional canned pump 200 shown in FIG. 10 still have the following problems.

In the canned pump 100 shown in FIG. 9, since the external conduit 191 is required, the number of parts is increased, the number of assembling steps is increased, and further, the external conduit 191 occupies a space around the pump. Since it occupies, the bulkiness of the pump is increased accordingly, and the installation place of the pump 100 is restricted.

In the canned pump 200 shown in FIG. 10, it is necessary to form a through hole in the shaft 232 in the axial direction, and such processing is extremely difficult, and as a result, the manufacturing cost of the pump rises.

The present invention has been devised under the above circumstances, and it is possible to more effectively discharge bubbles in the internal space of the can without increasing the number of parts and the manufacturing cost. It is an object to provide a canned pump that can be used.

[0021]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention adopts the following technical means.

That is, the canned pump provided by the present invention has a motor case, a stator fixed to an inner wall of the motor case, a rotor main body and a shaft passing through the rotor case, and a front end portion of the shaft. And a rear end of the motor case, which is rotatably supported on the case front wall and the case rear wall of the motor case via front slide bearings and rear slide bearings, respectively, to partition the stator from the rotor. And a tubular can whose front end is water-tightly connected to the case front wall and whose rear end is water-tightly connected to the case rear wall, and the rotor shaft are fitted on the case front wall side of the rotor. A washer for restricting axial movement, and a pump chamber that is formed adjacent to the case front wall and that includes an impeller attached to the front end of the rotor shaft. A canned pump having a circulation path for circulating a fluid between the internal space of the can and the pump chamber, the circulation path being formed in the front wall of the case, wherein the rotor has the rotation in the vicinity of its shaft. A fluid passage is formed that penetrates the child body in its axial direction, and the washer is rotated by the rotation of the rotor.
Radial flow forming means for providing a radial flow to the fluid sucked from the front end of the fluid passage is provided.

In a preferred embodiment, the fluid passage is provided as a concave groove formed in the inner surface of the shaft hole of the rotor body so as to extend in the axial direction.

Also in a preferred embodiment, the radial flow forming means has a plurality of grooves formed in the rear end surface of the washer so as to extend in the radial direction, and is directed radially outward on the peripheral surface of the washer. And a fin formed in a rib shape so as to project.

Due to the circulation path formed in the front wall of the case, the bubbles existing in the space inside the front wall of the case, that is, the space between the front wall of the case and the rotor body during pump operation are discharged into the pump chamber. To be done.

Further, as the washer rotates with the rotation of the motor, the suction negative pressure is generated near the front end outlet of the fluid passage passing through the rotor main body by the action of the radial flow forming means formed on the washer. To work. Accordingly, the fluid in the space between the rear surface of the rotor body and the case rear wall flows into the space between the front surface of the rotor body and the case front wall through the fluid passage, and corresponds to the amount. A fluid circulation is achieved in which a quantity of fluid is returned through the gap between the peripheral surface of the rotor body and the inner wall of the can to the space between the rear surface of the rotor body and the rear wall of the case.

By such fluid circulation, the bubbles existing in the space between the rear surface of the rotor body and the case rear wall are transferred to the space between the front surface of the rotor body and the case front wall.
As described above, the air bubbles existing in the space between the front surface of the rotor body and the front wall of the case are discharged to the outside through the circulation path formed on the front wall of the case. The bubbles existing in all parts of the internal space of the are discharged to the outside.

In a preferred embodiment, the rear end of the rotor shaft penetrates the rear wall of the case,
While being projected into a sealed space formed adjacent to the case rear wall, the shaft of the rotor is
A second fluid passage is provided extending from the rear end surface to the front end side in the axial direction and opening in a region between the rotor body and the rear slide bearing in the internal space of the can.

In this structure, since the rear end of the shaft is rotatably supported by the slide bearing, the bubbles existing in the sealed small chamber, which is necessarily provided outside the rear wall of the case, can be effectively discharged. Is. That is, the second fluid passage is opened on the peripheral surface of the shaft between the case rear wall and the rotor body. Thus, when the shaft rotates, this second fluid passage acts as a centrifugal pump,
Thus, the bubbles existing in the small chamber are transferred to the space between the case rear wall and the rotor body through the second fluid passage together with the fluid in the small chamber. The fluid in the space between the case rear wall and the rotor main body flows into the small chamber through the clearance between the rear slide bearing and the shaft so as to compensate for such fluid transfer.

As described above, the bubbles existing in the space between the case rear wall and the rotor body are effectively discharged.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the drawings.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of a canned pump according to the present invention, and FIG. 2 is a view showing the washer in FIG. 1 from the rear end face side. FIG. 3 shows II of FIG.
Sectional drawing which follows the I-III line, FIG. 4 is IV-IV of FIG.
5 is a sectional view taken along the line VV in FIG. 1. 6 to 8 are views for explaining the operation of the canned pump shown in FIG. It should be noted that in these figures, members and portions similar to those shown in FIGS. 9 and 10 showing a conventional example are denoted by the same reference numerals.

As shown in FIG. 1, in the canned pump A, a pump chamber 70 is arranged adjacent to the motor M, and at the tip of the output shaft 32 of the motor M,
The impeller 7 arranged in the pump chamber 70 is directly attached and is configured to rotate the impeller 7.

The motor M comprises a motor case 1, a stator 2 fixed to the inner wall of the motor case 1, a rotor body 31 and a rotor 3 having a shaft 32 penetrating the rotor body 31. A can 4 partitions the stator 2 and the rotor 3. The motor case 1
Is a member forming the exterior of the motor M, and is the case body 1
0, a case front wall 11, and a case rear wall 12. The case front wall 11 is integrally formed of metal or the like, and is attached to the front end side of the case body 10 so as to seal it. The central part of the case front wall 11 is
As shown in detail in FIG. 5, the boss-shaped front bearing bracket 11a is formed so as to project toward the rear end so as to have a generally cylindrical shape as a whole. This front bearing bracket 11a
Is a portion that supports a front slide bearing 5a described later, and this front slide bearing 5a is fitted to the rear end side of the front bearing bracket 11a as shown in FIG. In addition, the front bearing bracket 11 a is provided with a circulation path 8 for circulating a fluid between the internal space of the can 4 and the pump chamber 70. As shown in detail in FIG. 5, the circulation passage 8 is provided with a plurality of inflow passages 81 axially formed through the front bearing bracket 11a in the radial direction.
And a plurality of outflow passages 82 axially penetrating inside the front bearing bracket 11a. The inflow path 81 is a fitting hole 11 for fitting the front slide bearing 5a in the front bearing bracket 11a.
A groove appears on a part of the inner surface of a ₁ .

As shown in FIG. 1, the case rear wall 12 is formed integrally with the case body 10 so that the rear end of the case body 10 is closed. Case back wall 12
The central portion of the, with protruding front end, are axial through-holes 12a ₁ boss-like protrusions 12a formed is formed, on its front side, a bracket 12b for the rear sliding bearing is fitted ing. The rear bearing bracket 12b has a main body portion 12b ₁ of substantially cylindrical, and a flange portion 12b ₂ formed in its front end. A rear slide bearing 5b is fitted in the rear bearing bracket 12b.

Also, after the rear bearing bracket 12b,
The inner diameter on the end side is enlarged, and the cap 90 is attached to the rear end.
Is removably attached with a screw,
Room R ₁Are formed.

The stator 2 is a member that forms a field of the motor M, and includes a field iron core 2a and a field winding 2b. The field iron core 2a is formed by stacking those formed by punching out silicon steel plates and the like into a predetermined shape. The field winding 2b is formed in a shape such that a round copper wire or a rectangular copper wire is wound around the field iron core 2a,
For example, it is insulated from the field core 2a by being entirely covered with insulating paper, cotton tape, glass tape, or the like.

The rotor body 31 is a member that forms an armature of the motor M, and includes an armature core 31a and an armature winding 31b. The armature core 31a is formed into a substantially cylindrical shape as a whole by stacking stainless steel plates punched into a predetermined shape. A plurality of groove-shaped slots (not shown) extending in the axial direction are formed on or around the peripheral surface of the armature core 31a. The rotor body 31 is a so-called squirrel cage rotor, and a squirrel cage winding is used as the armature winding 31b. This squirrel cage winding 31b has copper rods (not shown) embedded in each slot of the armature core 31a, and both ends thereof are welded or brazed to an end ring 31b ₂ formed of copper into an annular shape. And the like.

The rotor body 31 has a central through hole 31a ₂
Is formed, and the shaft 32 is press-fitted into the central through hole 31a ₂ . In the present invention, a plurality of fluid passages 9 that penetrate the rotor body 31 in the axial direction in the vicinity of the shaft 32 are formed in the rotor 3 configured as described above. It is configured like. That is, as shown in FIGS. 1 and 4, the inner surface of the central through hole 31a ₂ of the rotor body 31 (the armature core 31a), so as to extend in the axial direction 2
One concave groove is formed, and these concave grooves 31a ₃
Cooperate with the peripheral surface of the shaft 32 to form a plurality of fluid passages 9 that axially penetrate the rotor body 31.

When the shaft 32 is press-fitted into the rotor body 31, the inner diameter of the central through hole 31a ₂ of the rotor body 31 is set to be slightly smaller than the outer diameter of the shaft 32. as can be through-holes 31a ₂ is relatively easily elastically expanded, the center through-hole 31a ₂
A groove extending in the axial direction may be formed on the inner surface of the. In this embodiment, the fluid passage 9 is realized by utilizing such a groove.

In the rotor 3, the front end portion and the rear end portion of the shaft 32 are inserted into the front slide bearing 5a and the rear slide bearing 5b, respectively, so that the case front wall 11 and the case rear wall 12 are inserted. It is rotatably supported. As described above, the front end portion of the shaft 32 further extends from the front slide bearing 5a and the case front wall 11 and reaches the inside of the pump chamber 70.
Is installed. The rear end of the shaft 32 further extends from the rear slide bearing 5b and faces the small chamber R ₁ formed outside the case rear wall 12.

The front slide bearing 5a and the rear slide bearing 5b are formed of a material having excellent wear resistance such as carbon. These slide bearings 5
a and 5b have a clearance of about 50 to 60 μm formed between the inner surface thereof and the outer peripheral surface of the shaft 32.
Its inner diameter is set.

A washer 6 for restricting the axial movement of the rotor 3 is provided on the shaft 32, and the washer 6 is provided.
It is fitted in a portion between the front slide bearing 5a and the front slide bearing 5a.
The washer 6 is made of, for example, hard rubber and has a substantially cylindrical shape as a whole. A thrust collar 6a (see FIG. 3) made of, for example, ceramic is attached to the front end side of the washer 6 to avoid wear due to frictional contact with the front slide bearing 5a.

In the present invention, the washer 6 is
A radial flow forming means 60 is provided for giving a radial flow to the fluid by rotating together with the rotor 3, but in this embodiment, it is formed as follows.

That is, as shown in detail in FIGS. 2 and 3, a plurality of radially extending grooves 61 are formed on the rear end face of the washer 6, and the outer peripheral surface of the washer 6 is radially outward. A plurality of fins 62 extending in one direction are formed.

As shown in FIG. 1, the shaft 32 further extends from the rear end face facing the small chamber R ₁ to the front side in the axial direction, the rear slide bearing 5b and the rotor body 3 are provided.
The second fluid passage 9b is formed in the area S ₁ between the _first fluid passage 9 and the first fluid passage ₁ . The second fluid passage 9b is connected to the shaft 3
Axial hole 9b with a predetermined depth from the rear end surface of 2 using a drill
It can be easily formed by forming a ₁ and forming a diametrically extending hole 9b ₂ with a drill so as to be connected to the tip of the axial hole 9b ₁ .

As described above, the space inside the motor case 1 is partitioned by the stator 2 and the rotor 3 by the can 4 formed of a material having excellent corrosion resistance such as stainless steel. Partitioned. The can 4 has a cylindrical shape as a whole, and as shown in FIG. 1, its front end portion is the case front wall 11 and its rear end portion is the case rear wall 12.
Are watertightly connected. Specifically, the front end portion of the can 4 is the front bearing bracket 1 of the case front wall 11.
It is fitted onto 1a, and an O-ring 4a is interposed between them. On the other hand, an inward flange 41 is formed at the rear end of the can 4, and the inward flange 41 is formed between the flange portion 12b ₂ of the rear bearing bracket 12b and the protrusion 12a of the rear wall 12 of the case. It is sandwiched via a ring 4b.

The impeller 7 in the pump chamber 70 has a rear shroud 71 formed in a circular shape in a plan view, a front shroud 72 arranged on the front side of the rear shroud 71 with a predetermined space, and these rear shrouds 71. The front shroud 71 and a plurality of blades 74 are disposed between the shroud 71 and the front shroud 71, and are made of, for example, resin.

A hub 73 is formed at the center of the rear shroud 71, and the impeller 7 is attached to the front end of the shaft 32 by fitting the shaft 32 into the hub 73. A plurality of through holes 71b are formed in the hub 73 at a predetermined distance in the radial direction, and the suction port 72a of the impeller 7 and the rear surface side of the rear shroud 71 are communicated with each other. A skirt portion 71a extending rearward in a cylindrical shape is formed on the rear surface side of the rear shroud 71, and the skirt portion 71a is formed.
Is extended into an annular groove 11b provided on the front side of the case front wall 11. This allows the rear shroud 7
The radial flow of the fluid on the rear side of 1 is blocked.
A substantially cylindrical suction port 72a is formed at the center of the front shroud 72.

The pump chamber 70 is a space surrounded by a pump wall 70c made of metal or the like, and is formed adjacent to the case front wall 11 of the motor M. The pump chamber 70 is connected to a water supply passage P ₁ communicating with the water supply inlet 70 a of the impeller 7 and a drainage passage P ₂ for discharging the fluid.

Next, the canned pump A having the above structure.
The action of will be explained.

The canned pump A is operated in a state where the internal space of the can 4 in the pump chamber 70 or the motor M is filled with fluid. The fluid is filled in the internal space of the can 4 by removing the cap 90 attached to form the sealed small chamber R ₁ in the rear wall 12 of the case and applying a suction force to this portion. Be seen. The fluid is the front slide bearing 5a.
And the inner peripheral surface of each of the rear slide bearings 5b and the shaft 3
It also penetrates into the clearance between the outer peripheral surface of the shaft 2 and the outer peripheral surface of the shaft 2 to form a liquid film, thereby performing axial lubrication of the shaft 32. Due to the operation of the motor M, the rotation of the rotor 3 causes the impeller 7 in the pump chamber 70 to rotate, thereby performing a centrifugal pump action to drain the fluid sucked from the water supply passage P ₁ to the drainage passage P ₂ .

Hub 7 of rear shroud 71 of impeller 7
3 is connected to the outflow passage 82 formed in the front wall 11 of the case, and the skirt portion 71a formed in the rear shroud 71 is formed in the rear shroud 7.
1, which impedes the radial flow of the fluid on the rear side of 1, the negative pressure of the suction port 72a of the impeller 7 acts on the outflow passage 82, and as a result, as shown in FIG.
The fluid in the space S ₂ between the rotor body 31 and the rotor body 31 is sucked and discharged. At the same time, the suction force also acts on the clearance between the front slide bearing 5a and the shaft 32, causing the fluid to flow to the outside. The filling of the fluid in an amount corresponding to the amount of suction and discharge of the fluid as described above is performed by the outflow passage 8 in the case front wall 11.
It is performed via an inflow passage 81 formed so as to penetrate outward in the radial direction of 2. By achieving such fluid circulation through the case front wall 11, the bubbles generated by the cavitation due to the rotation of the impeller 7 and entering the internal space of the can 4 are effectively discharged.

The washer 6 fitted between the rotor body 31 of the shaft 32 and the front slide bearing 5a is
As shown in FIG. 7, the space S between the case rear wall 12 and the rotor body 31 is generated by the action of the radial flow forming means realized by the groove portion 61 on the rear surface and the fins 62 on the peripheral surface.
The fluid of ₁ flows toward the space S ₂ between the rotor body 31 and the case front wall 11 via the fluid passage 9, and the fluid of this space S ₂ is applied to the outer peripheral surface of the rotor body 31 and the can 4. A fluid circulation is realized in which the fluid flows into the space S ₁ through the clearance between the inner peripheral surface of the space. The radial flow forming means,
The so-called centrifugal pump action realizes the above-mentioned fluid circulation. As a result, even if bubbles are present in the space S ₁ between the case rear wall 12 and the rotor body 31, the bubbles are moved to the space S ₂ between the rotor body 31 and the case front wall 11. be able to. As described above, if the bubbles move to the space S ₂ , they are discharged to the outside through the outflow passage 82, as described above.

At the time of installing the pump, the cap 90 may be removed and the air bubbles (air) in the small chamber R ₁ may be discharged. Nevertheless, the air bubbles may still remain in the small chamber R ₁ . In the canned pump according to this embodiment, even the residual bubbles in the small chamber R ₁ can be effectively discharged to the outside. That is, the front end portion of the second fluid passage 9b has the space S ₁ on the inner peripheral surface of the shaft 32.
The second fluid passage 9b is opened toward the second fluid passage 9b.
Performs a centrifugal pump action by the rotation of the shaft 32. That is, as shown in FIG. 8, the fluid in the small chamber R ₁ flows into the space S ₁ via the second fluid passage 9b. The fluid that compensates for this flow flows into the small chamber R ₁ from the clearance between the rear slide bearing 5b and the shaft 32.
Therefore, even if air bubbles exist in the clearance between the rear slide bearing 5b and the shaft 32, the air bubbles are
After flowing into the small chamber R ₁ , it is transferred to the space S ₁ through the second fluid passage 9b. The bubbles existing in the space S ₁ are transferred to the space S ₂ via the fluid passage 9 as described above.

As described above, in the canned pump A having the above structure, the fluid in any part of the space inside the can 4 is
As a result, it can be discharged to the outside through the outflow passage 82. Therefore, including the small chamber R ₁ on the rear side of the case rear wall 12,
Bubbles existing in any space inside the can 4 can be effectively discharged to the outside, and a problem caused by the bubbles staying inside the can 4, that is, the front slide bearing 5
It is possible to solve the problem of poor lubrication of the a and the rear slide bearing 5b, and to relieve the user from the trouble of maintenance.

Of course, the present invention is not limited to the above-described embodiments, and all design changes within the scope of the matters described in the claims are included in the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of a canned pump according to the present invention.

FIG. 2 is a diagram showing the washer in FIG. 1 from the rear end side.

3 is a cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG.

5 is a cross-sectional view taken along the line VV of FIG.

FIG. 6 is a diagram for explaining the operation of the canned pump shown in FIG. 1.

FIG. 7 is a diagram for explaining the operation of the canned pump shown in FIG.

FIG. 8 is a diagram for explaining the operation of the canned pump shown in FIG. 1.

FIG. 9 is a schematic sectional view showing an example of a conventional canned pump.

FIG. 10 is a schematic cross-sectional view showing another example of a conventional canned pump.

[Explanation of symbols]

1 motor case 2 stator 3 rotor 4 can 5a Front plain bearing 5b Rear slide bearing 6 washers 7 Impeller 8 circuit 9 fluid passages 9b Second fluid passage 11 Case front wall 12 case back wall 31 Rotor body 32 shaft 60 Radial flow forming means 61 groove 62 fins 70 pump room 90 cap A canned pump M motor

Claims (4)

[Claims] 1. A motor case, a stator fixed to an inner wall of the motor case, a rotor main body and a shaft penetrating the rotor main body, and a front end portion and a rear end portion of the shaft have a case of the motor case. The rotor is rotatably supported on the front wall and the rear wall of the case by front slide bearings and rear slide bearings, respectively, and the front end is divided into the front wall of the case so as to partition between the stator and the rotor. , A cylindrical can whose rear end is watertightly connected to the case rear wall, and a shaft of the rotor, which is fitted on the case front wall side, for restricting the axial movement of the rotor. Formed adjacent to the washer and the front wall of the case,
A canister having a pump chamber including an impeller attached to a front end of a shaft of the rotor, and a circulation path for circulating a fluid between an inner space of the can and the pump chamber formed in the front wall of the case. In the pump, a fluid passage is formed in the rotor in the vicinity of the shaft thereof so as to penetrate the rotor main body in the axial direction thereof, and the washer is associated with rotation of the rotor. A canned pump, further comprising radial flow forming means for providing a radial flow to the fluid sucked from the front end of the fluid passage. 2. The canned pump according to claim 1, wherein the fluid passage is provided as a concave groove formed in an inner surface of the shaft hole of the rotor main body so as to extend in the axial direction. 3. A rear end portion of a shaft of the rotor penetrates through a rear wall of the case and projects into a sealed space formed adjacent to the rear wall of the case. A second fluid passage extending from the rear end surface to the front end side in the axial direction of the shaft of the child, and opening in a region between the rotor body and the rear slide bearing in the internal space of the can. The canned pump according to claim 1, wherein the canned pump is provided. 4. The radial flow forming means has a plurality of groove portions formed in a concave shape on the rear end surface of the washer so as to extend in the radial direction, and projects radially outward in the peripheral surface of the washer. The canned pump according to any one of claims 1 to 3, comprising a plurality of fins formed as described above.