JP2000120588A - Impeller fixing structure of canned motor pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To forcibly fix an impeller to a shaft by forming a cylindrical step difference part on a shaft end part, forming a taper hole opposed to the step difference part at prescribed clearances on a boss part of an impeller, and interposing a taper bush between the taper hole and the step difference part. SOLUTION: In the case where an impeller 7 in a canned motor pump is fixed to a shaft 6, a cylindrical surface 25a of a taper bush 25 is inserted to an outer peripheral surface of a cylindrical step difference part 14 formed on an end part of the shaft 6 to a prescribed position. A taper hole 30 of a boss part 15 of the impeller 7 is fitted to a taper surface 25b side of the taper bush 25. After that, a screw part 21a of an impeller bolt 21 is screwed around a screw hole 20 of the shaft 6 through a washer assembly 19, and an end surface 15c of the boss part 15 of the impeller 7 abuts on an end surface 13a of a shaft sleeve 13. In this condition, the impeller bolt 21 is fastened, the taper bush 25 is moved in an axial direction, and the impeller 7 is wedged to the shaft 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canned motor pump, and more particularly to an impeller fixing structure capable of stably fixing an impeller to an end of a shaft for a long time by tightening an impeller bolt.

[0002]

2. Description of the Related Art Generally, a canned motor pump 1 is
As shown in FIG. 8, the pump unit 3 includes a canned motor unit 2 and a pump unit 3 connected by an adapter 4.
Is a shaft 6 rotatably supported by a pair of bearings 5 (only one bearing 5 is shown) in the canned motor unit 2.
(Irapella shaft). End 6 of this shaft 6
The impeller 7 is fixed to a, and the impeller 7 is rotatably disposed in a pump chamber 11 formed between the suction pipe section 9 and the discharge pipe section 10 of the case 8 of the pump section 3.

As a structure for fixing the impeller 7 to the end 6a of the shaft 6, conventionally, for example, a fixing structure shown in FIGS. 9 and 10 is employed. First, in the fixing structure shown in FIG. 9, a shaft sleeve 13 whose one end (the side of the canned motor 2) is in contact with a thrust washer 12 (see FIG. 8) is inserted into the end 6a of the shaft 6, and A cylindrical step 14 is provided at the end 6 a of the impeller 6, and a boss 15 of the impeller 7 is provided on the outer peripheral surface of the step 14.
Shaft hole 15a is fitted.

A key groove 16 formed on the outer peripheral surface of a step portion 14 of the shaft 6 and a key groove 17 formed in a shaft hole 15a of a boss portion 15 of the impeller 7 are fitted with a key 18 in a state where the key 18 is fitted. 7 is fitted to the shaft 6, and a screw hole 20 formed in the end face of the shaft 6 via the washer assembly 19.
, And screw the impeller bolts 21 into place. Thereby, the tightening force of the impeller bolt 21 is reduced to the washer assembly 19.
And a shaft sleeve 13 in which an end face 15c on the other end of the boss 15 is positioned by a thrust washer 12 via an end face 15b on one end of the boss 15 of the impeller 7.
The impeller 7 is fixed to the shaft 6 by contacting the end surface 13a of the impeller 7 with a predetermined pressure.

In the fixing structure shown in FIG. 10, a conical tapered surface 22 whose diameter decreases toward the outside (toward the impeller bolt 21) is formed at the end 6a of the shaft 6, and the boss portion of the impeller 7 is formed. 15 shows the tapered surface 2 of the shaft 6
2 to form a tapered hole 23 having a tapered surface corresponding to
Key grooves 16 and 17 provided in tapered surface 22 and tapered hole 23
The taper hole 23 of the boss 15 of the impeller 7 is fitted to the shaft 6 with the key 18 fitted in the shaft 6. Then, the impeller bolt 21 is screwed into the screw hole 20 of the shaft 6 via the washer assembly 19 and tightened, so that the tapered hole 23 of the boss 15 is brought into close contact with the tapered surface 22 of the shaft 6 to fix the impeller 7 to the shaft 6. It is something to do.

[0006]

However, in the fixing structure shown in FIG. 9, the clearance between the key 18 and each of the key grooves 16, 17 is set, for example, in the longitudinal direction to improve the assemblability. Therefore, the key 18 moves depending on the operation state of the canned motor pump 1, and its end surface contacts the end surfaces of the key grooves 16 and 17 with a predetermined pressure. When the contact caused by the movement of the key 18 is repeated over a long period of use of the canned motor pump 1, the key grooves 16, 17 and the key 18 that come into contact with each other wear, and the fixing strength of the impeller 7 to the shaft 6 decreases. For example, impeller 7
The shaft 6 of the impeller 7 may be loose.
It is difficult to obtain a stable fixed state over a long period of time.

As a result, for example, the efficiency of the pump is reduced due to the backlash of the impeller 7, so that the worn key 18
Since the shaft 6 and the impeller 7 having the worn keyways 16 and 17 need to be replaced, there is a problem that the life of the canned motor pump 1 is easily shortened. Maintenance work of the canned motor pump 1 becomes troublesome.

Further, in the fixing structure shown in FIG.
Since the fitting is performed by the tapered surface 22 and the tapered hole 23, the wear of the key 18 and the like is reduced as compared with the fixing structure shown in FIG. 9, but the tapered surface 22 of the shaft 7 and the taper of the boss 15 of the impeller 7 are reduced. Due to the dimensional tolerance of the hole 23, the fixed position of the impeller 7 in the axial direction of the shaft 6 tends to vary, which affects the axial thrust of the canned motor pump 1 and the back surface 7a of the impeller 7 and the inner surface of the pump chamber 11 shown in FIG. There has been a problem that the gap between 11a, that is, the position of the impeller in the pump chamber 11 tends to be unstable.

Also, depending on the dimensional variation between the tapered surface 22 and the tapered hole 23, the end surface 15c of the boss portion 15 of the impeller 7 on the side opposite to the impeller bolt 21 may be used.
May not come into contact with the end surface 13a of the shaft 6, and a separate stopper member for fixing parts other than the impeller 7 such as the shaft sleeve 13 and the thrust washer 12 to the shaft 6 is required. And it is difficult to easily cope with the current model.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a long-term stable fixing state of an impeller to a shaft and a position of an impeller in a pump chamber. The present invention is to provide an impeller fixing structure in a canned motor pump that can stabilize the pump and extend the life of the pump. The object of the invention described in claim 3 or 4 is, in addition to the object of the invention described in claim 1 or 2, in that a stopper member such as a shaft sleeve can also be used for the tapered bush, thereby simplifying the configuration. Another object of the present invention is to provide an impeller fixing structure in a canned motor pump which can easily be adapted to a current model by improving assemblability and the like. Also,
The object of the invention described in claim 5 is, in addition to the object of the invention described in claim 4, an impeller fixing in a canned motor pump in which rotation of the impeller shaft in the direction around the axis is reliably prevented to obtain a more stable fixing state. It is to provide a structure.

[0011]

In order to achieve the above object, the invention according to claim 1 of the present invention has a canned motor portion and a pump portion, and is rotatably supported by a bearing in the canned motor portion. In a canned motor pump in which the boss of the impeller is fixed to the end of the shaft located in the pump section by tightening the impeller bolt, a cylindrical step is formed at the end of the shaft and the boss of the impeller is formed. A tapered hole having a predetermined gap is formed with respect to the step portion of the shaft, and between the tapered hole of the impeller and the step portion of the shaft, an outer peripheral surface is formed with a tapered surface corresponding to the tapered hole of the boss portion of the impeller, The impeller is fixed to the shaft by interposing a taper bush whose inner peripheral surface is formed by a cylindrical surface corresponding to the outer peripheral surface of the step portion of the shaft.

With this configuration, the cylindrical inner surface of the taper bush is fitted to the step at the end of the shaft, and the outer surface of the taper bush is formed on the outer surface of the impeller boss. The tapered hole fits. In this state, when the impeller bolt is screwed into the screw hole at the end of the shaft via a washer assembly and tightened, a wedge effect is obtained by the tapered bush having the outer peripheral surface formed by the tapered surface, and the inner and outer peripheral surfaces of the tapered bush are formed. The outer peripheral surface of the step portion of the shaft and the tapered hole of the boss portion of the impeller both come into surface contact. As a result, the impeller is firmly fixed to the shaft via the taper bush, eliminating the need for a conventional key, eliminating wear of the key and key groove, and eliminating the occurrence of rattling of the impeller and the position of the impeller in the pump chamber. Stable and prolonged life of the canned motor pump.

Further, the invention according to claim 2 is characterized in that a slit communicating with the inner and outer peripheral surfaces is formed in the taper bush in the axial direction. With this configuration, when pressure is applied to the outer peripheral surface of the taper bush by the boss portion of the impeller due to the tightening of the impeller bolt,
The slit formed at a predetermined gap in the axial direction of the taper bush is narrowed, and the inner and outer peripheral surfaces of the taper bush and the tapered hole of the step portion or the boss portion of the shaft are surely in surface contact,
The impeller is firmly fixed by the end of the shaft.

According to a third aspect of the present invention, when the tapered surface of the tapered bush is fixed to the end of the shaft via the tapered bush by tightening the impeller bolt, the impeller bolt of the boss portion of the impeller is fixed. The end surface on the mounting side is set to have a taper angle that can abut the end surface of the shaft sleeve inserted into the shaft.

With this configuration, when the impeller is fixed to the shaft via the tapered bush, the end surface of the boss portion abuts against the end surface of the shaft sleeve to determine the axial position of the impeller and the shaft. Therefore, the taper bush can also be used as a stopper member for the shaft sleeve or the thrust washer, so that the configuration of the shaft seal mechanism is simplified, and the compatibility with the current model is also facilitated.

According to a fourth aspect of the present invention, the tapered surface of the tapered bush is formed with a tapered surface that decreases in diameter toward the impeller bolt, and the tapered bush has a large diameter at the end on the side opposite to the impeller bolt. A flange portion is formed, and the impeller and the shaft are axially positioned and fixed via a taper bush by contacting an end surface of the flange portion with an end surface of a shaft sleeve inserted into the shaft. I do.

With this configuration, the end surface of the flange portion of the tapered bush can be constantly brought into contact with the end surface of the shaft sleeve. Therefore, the tapered bush also serves as a stopper for the shaft sleeve and the thrust washer with respect to the shaft. In addition, the impeller bolt side has a tapered surface formed with a small diameter, so that the impeller can be easily attached to the tapered bush and can be easily adapted to current models.

According to a fifth aspect of the present invention, the width of the slit of the taper bush is such that the width of the slit in the key groove formed in the tapered hole of the boss portion of the impeller and the outer peripheral surface of the step portion of the shaft is reduced. The width is set to be larger than the width.

With this configuration, the key reliably prevents the rotation of the impeller shaft around the axis, and the taper bush can be deformed by the slit having a width larger than the key width. The inner and outer peripheral surfaces surely make surface contact with the outer peripheral surface of the step portion of the shaft and the tapered hole of the boss portion of the impeller, and the impeller is more securely and firmly fixed to the shaft.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. 1 to 3 show an embodiment of an impeller fixing structure in a canned motor pump according to the present invention. FIG. 1 is a half sectional view of a main part thereof, FIG. 2 is a front view of a tapered bush, and FIG. It is sectional drawing. The same parts as those of the canned motor pump shown in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, a cylindrical step 14 is formed at the end 6a of the shaft 6 of the pump section 3, and the tapered bush 2
5 are fitted. This taper bush 25 is shown in FIG.
As shown in FIG. 3, the inner peripheral surface is formed by a cylindrical surface 25 a having an inner diameter D <b> 1, and the outer peripheral surface has an outer diameter D <b> 2 at one axial end (the impeller bolt 21 side) and the other end ( The outside diameter of the anti-impeller bolt 21 is D3 (D2> D3)
Is formed by the tapered surface 25b.

In the peripheral wall of the taper bush 25, a slit 26 having a width W1 communicating from the outer peripheral surface side to the inner peripheral surface side is formed over the entire area in the axial direction. This slit 26
Accordingly, when pressure is applied to the tapered surface 25b of the tapered bush 25, the tapered bush 25 is deformed (narrowed) to a position where the both end surfaces of the slit 26 abut in the direction of arrow A in FIG.

Further, a jig 27 for removing the taper bush 25 is provided on the outer peripheral surface on one end side of the taper bush 25.
A locking recess 28 having a rectangular cross section in which the locking portion (see FIG. 1) can be locked is formed in the circumferential direction, and a jig 27 of the jig 27 is provided outside (one end side) of the locking recess 28. A screw portion 29 to which the female screw portion is screwed is formed. This locking recess 28
The taper bush 25 interposed between the tapered hole 23 of the boss 15 of the impeller 7 and the step 14 of the shaft 6 is removed by using the screw part 29 and the screw part 29.

On the other hand, the end surface of the washer assembly 19 is in contact with the end surface of the tapered bush 25 on the screw portion 29 side.
The washer assembly 19 has an outer diameter of the tapered bush 2.
5 is slightly larger than the outer diameter D2, and a hole 19a is formed at the center of the outer diameter D2. An impeller bolt 21 is inserted into the hole 19a. This impeller bolt 21
Is screwed into a screw hole 20 formed at the end of the shaft 6.

The tapered hole 30 of the boss 15 of the impeller 7 is fitted to the tapered surface 25b which is the outer peripheral surface of the tapered bush 25. The boss 15 of this impeller 7
The taper hole 25 of the taper bush 25
The diameter of the end face 15b of the boss 15 is large and the diameter of the end face 15c is small. The end face 15c of the boss 15 abuts on the end face 13a of the shaft sleeve 13 inserted into the shaft 6, and the other end face of the shaft sleeve 13, as shown in FIG. The shaft sleeve 13 and the thrust washer 12 are brought into contact with the thrust washer 12 provided at the
Is positioned and fixed.

Next, an example of a method of fixing the impeller 7 to the shaft 6 in the fixing structure will be described.
First, the cylindrical surface 25a of the tapered bush 25 is fitted to the outer peripheral surface of the step portion 14 of the shaft 6 to a predetermined position, and the tapered hole 30 of the boss portion 15 of the impeller 7 is fitted to the tapered surface 25b side of the tapered bush 25. . Then, the screw portion 21 a of the impeller bolt 21 is screwed into the screw hole 20 of the shaft 6 via the washer assembly 19, and the impeller 7 is
The end surface 15c of the boss 15 is brought into contact with the end surface 13a of the shaft sleeve 13.

In this state, when the impeller bolt 21 is tightened, the washer assembly 19 moves together with the impeller bolt 21 in the direction of arrow B in FIG. 1, and the end face of the washer assembly 19 contacts the end face on one end side of the tapered bush 25. Then, the taper bush 25 is moved in the same direction. As the tapered bush 25 moves in the direction of arrow B, the tapered bush 25 enters as a wedge between the tapered hole 30 of the boss 15 of the impeller 7 and the outer peripheral surface of the step portion 14 of the shaft 6.

At this time, since the tapered bush 25 has an axial slit 26 formed in the peripheral wall thereof, the pressure of the boss 15 due to the movement in the direction of arrow B is reduced.
In addition, the slit 26 moves while deforming in the direction in which the slit 26 becomes narrower (the direction of the arrow A in FIG. 2), and stops at the position where the end faces of the slit 26 abut against each other. The movement of the taper bush 25 in the axial direction of the shaft 6 is regulated by the taper angle between the taper surface 25b and the taper hole 30, the thickness of the taper bush 25, the gap between the taper hole 30 of the shaft 6, and the like. Even if the movement cannot be restricted by these, the movement is reliably prevented by the step portion 14 of the shaft 6.

As a result, the tapered surface 25b of the tapered bush 25 comes into surface contact with the tapered surface of the tapered hole 30 of the boss portion 15, and the cylindrical surface 25a also has the stepped portion 14 of the shaft 6.
The impeller 7 comes into surface contact with the outer peripheral surface of the
fixed to a. At this time, the positioning of the impeller 7 in the axial direction is performed by the end face 15 c of the boss 15 and the shaft sleeve 13.
Is determined by the contact of the end face 13a. The assembling of the impeller is not limited to the above example. For example, the taper hole 30 of the boss 15 of the impeller 7 is inserted into the step 14 of the shaft 6 in advance, and the step The tapered bush 25 may be inserted between the outer peripheral surfaces of the portion 14 in the same manner as a general wedge, and assembled.

As described above, according to the impeller 7 fixing structure of the above embodiment, the tapered hole 3 is formed in the boss 15 of the impeller 7.
0, and a tapered bush 25 having a tapered surface 25b corresponding to the tapered surface of the tapered hole 30 and a cylindrical surface 25a corresponding to the outer peripheral surface of the step portion 14 of the shaft 6 is interposed between the impeller 7 and the shaft 6. Since the taper bush 25 has a wedge effect, the inner and outer surfaces 25a and 25b of the taper bush 25 come into surface contact with the outer peripheral surface of the step portion 14 and the tapered hole 30 of the boss portion 15, The impeller 7 can be firmly fixed to the shaft 6 in a state where the movement of the impeller 7 with respect to the shaft 6 in the axial direction and the direction around the axis is restricted.

As a result, it is not necessary to use the key 18 for fixing the impeller 7 and the shaft 6 as in the conventional case, and the key 18 and the key grooves 16 and 17 are worn due to long-term use of the canned motor pump 1. And the life of the shaft 6 and the impeller 7, that is, the life of the canned motor pump 1 itself can be extended, whereby the maintenance frequency of the canned motor pump 1 can be reduced and the maintenance work can be facilitated. It becomes possible to plan.

Particularly, since an axial slit 26 communicating with the inner and outer peripheral surfaces is formed in the peripheral wall of the tapered bush 25, the slit 26 can be narrowed by the pressure of the tapered hole 30 of the boss 15 of the impeller 7. The surface contact between the inner and outer surfaces 25a and 25b of the tapered bush 25 and the outer peripheral surface of the step portion 14 of the shaft 6 and the tapered hole 30 of the boss portion 15 can be more favorably maintained.
Can be further enhanced in fixing strength to the shaft 6.

Further, since the positioning of the impeller 7 in the axial direction is performed by the end face 15c of the boss portion 15 and the end face 13a of the shaft sleeve 13, the gap t between the impeller 7 and the inner face 11a of the pump chamber 11 (FIG. ) Can be easily set to design values, and the impeller 7 is firmly fixed to the shaft 6 by surface contact, so that the gap t does not change due to the use of the canned motor 1 and the impeller does not change. The position of the pump 7 in the pump chamber 11 can be stabilized, and a stable pump operation can be performed for a long time.

Further, since the step portion 14 of the shaft 6 is formed in a cylindrical shape, the conventional shaft 6 can be used as it is, and the structure for stopping the shaft sleeve 13 and the thrust washer 12 on the shaft 6 is the same as the conventional one. A structure (fixed structure by the end face 15c of the boss 15 of the impeller 7) can be adopted, and a shaft hole formed in the boss 15 of the impeller 7 is changed to a tapered hole 30, and a tapered bush 25 corresponding to this processing is set. Therefore, it is possible to easily cope with the current model canned motor pump 1 without making a major design change.

Further, since the conventional shaft can be used as it is, there is no need to change the length of the shaft 6, and the total length of the canned motor pump 1 is increased, that is, the canned motor pump 1 is increased in size. Can be prevented. Furthermore, the taper bush 25
Since the locking recess 28 and the screw portion 29 are formed on the outer peripheral surface of the canned motor pump 1, for example, when the cand motor pump 1 is disassembled and repaired, the tapering is performed using the locking recess 28 and the screw portion 29. The bush 25 can be removed,
The canned motor pump 1 can be replaced easily.
Maintenance work can be performed easily and efficiently.

4 to 7 show another embodiment of the impeller fixing structure in the canned motor pump according to the present invention. FIG. 4 is a half sectional view of a main part substantially similar to FIG. 1, and FIG.
FIG. 6 is a front view of the tapered bush, and FIG.
Is a side sectional view thereof. The same parts as those shown in FIGS. 1 and 8 are denoted by the same reference numerals and described. The feature of the tapered bush 32 of this embodiment is that the provision of the key 18 restricts the rotation of the impeller 7 around the axis, and the tapered surface 32b of the tapered bush 32 is opposite to the tapered surface 25b of the tapered bush 25. The point is that it is formed in a tapered shape and a flange 33 is provided on the other end side.

That is, at the position where the outer peripheral surface of the step portion 14 of the shaft 6 and the tapered hole 34 of the boss portion 15 of the impeller 7 in the opposite direction to the tapered hole 34 are opposed to each other, the key grooves 16, 1
7 is formed, and a key 18 is fitted in the key grooves 16 and 17. Further, as shown in FIG. 7, the tapered bush 32 interposed between the tapered hole 34 of the boss 15 of the impeller 7 and the outer peripheral surface of the step 14 of the shaft 6 has an outer diameter D2 at one end and an outer diameter D2 at the other end. Smaller than the outer diameter D3 (D2 <D3)
A large-diameter flange portion 33 is formed on the other end side. Further, the slit 35 formed in the peripheral wall of the tapered bush 32 has a width W2 (see FIG. 6) of the key 18.
Is set to be slightly larger than the width W3 (see FIG. 5).

To fix the impeller 7 to the shaft 6 in this embodiment, first, the key 18 is fitted into the key groove 16 of the step portion 14 of the shaft 6 and the key 18 is inserted into the slit 35.
And the cylindrical surface 32a of the tapered bush 32
The end surface 33 a of the flange portion 33 of the tapered bush 32 is brought into contact with the end surface 13 a of the shaft sleeve 13 by fitting the outer peripheral surface of the step portion 14 of the shaft 6.

Then, with the key 18 fitted in the key groove 17 of the tapered hole 34 of the boss 15 of the impeller 7,
The tapered hole 34 of the boss 15 is fitted to the tapered surface 32 b of the tapered bush 32. At this time, the boss 1 of the impeller 7
5 and the tapered surface 3 of the tapered bush 32
2b, the insertion side (the side opposite to the impeller bolt 21) is formed with a large diameter.
Can be easily fitted to the outside of the tapered bush 32.

When the boss 15 of the impeller 7 is fitted to the taper bush 32, the impeller bolt 21 is screwed into the screw hole 20 on the end face of the shaft 6 via the washer assembly 19, and the impeller 7 is tightened via the washer assembly 19. Of the boss 15 is moved in the direction of arrow B. The movement of the impeller 7 narrows the slit 35 of the taper bush 32 as in the above embodiment, and stops the movement of the impeller 7 at, for example, a position where the impeller 7 is in contact with both side surfaces of the key 18. At this time, the position of the impeller 7 in the axial direction is determined by the end surface 33 a of the flange 33 of the tapered bush 32.
Is in contact with the end surface 13a of the shaft sleeve 13, and is set at a predetermined position corresponding to the taper angle between the tapered hole 34 and the tapered surface 32b.

Also in this embodiment, the taper bush 3
The inner and outer surfaces 32a and 32b of the shaft 2
Is fixed in a surface contact state with the outer peripheral surface of the impeller 7 and the tapered hole 34 of the impeller 7, so that the same operation and effect as those of the above embodiment can be obtained, and the rotation of the impeller 7 in the direction around the axis is surely prevented by the key 18. Therefore, an operational effect that the impeller 7 can be firmly fixed to the shaft 6 is obtained. In this embodiment, as shown in FIG.
Of the six balance holes provided in the impeller 7, two balance holes 36 are formed by screw holes. By screwing a bolt of a jig into the screw holes, the impeller 7 is disassembled, that is, the taper bushing is disassembled. 32 can be removed.

In this embodiment, the use of the key 18 restricts the rotation of the impeller 7 about the shaft 6 in the direction around the axis, but the key 18 is not always necessary. 18 (and key grooves 16, 17) are omitted, and the tapered bush 2
Similarly to 5, it is of course possible to fix the taper bush 32 only by surface contact between the outer peripheral surface of the shaft 6 and the tapered hole 34.

In each of the above embodiments, the shape of the taper bush, such as the taper angle, the outer diameter and the length, the width of the slit, etc.
The shape of the boss portion of the impeller, the taper angle of the tapered hole, the disassembly mechanism of the impeller and the taper bush, and the like are merely examples, and various changes can be made without departing from the gist of the present invention. Not even.

[0044]

As described in detail above, according to the first aspect of the present invention, a wedge effect is obtained by the tapered bush having the outer peripheral surface formed by the tapered surface, and the step between the inner and outer peripheral surfaces of the tapered bush and the shaft is obtained. The outer peripheral surface of the part and the tapered hole of the boss part of the impeller are in surface contact with each other, and the impeller can be firmly fixed to the shaft via the tapered bush. At the same time, the position of the impeller in the pump chamber is stabilized, and the life of the canned motor pump can be extended.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the slit of the taper bush is narrowed by the pressure applied to the outer peripheral surface of the taper bush by the boss portion of the impeller by tightening the impeller bolt. Therefore, the inner and outer peripheral surfaces of the taper bush and the outer peripheral surface of the shaft and the tapered hole of the boss portion of the impeller surely come into surface contact, and the impeller can be more firmly fixed to the shaft.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect, when the impeller is fixed to the shaft via the tapered bush, the end face of the boss portion is formed by the shaft sleeve. Since the axial position of the impeller and the shaft is determined by abutting against the end face, the taper bush can be used as a stop member such as a shaft sleeve, so that the configuration of the shaft seal mechanism is simplified and the current model is used. Can be easily performed.

According to the fourth aspect of the invention, in addition to the effects of the first or second aspect, the end face of the flange of the tapered bush can be brought into contact with the end face of the shaft sleeve. The taper bush can also be used as a stopper member such as a shaft sleeve, which simplifies the configuration of the shaft seal mechanism, simplifies assembly of the impeller to the taper bush, and facilitates compatibility with current models. it can.

According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the present invention, the rotation of the impeller in the direction around the axis is prevented by the key, and the impeller is further strengthened by the shaft via the tapered busher. And the like.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a main part showing one embodiment of an impeller fixing structure in a canned motor pump according to the present invention.

FIG. 2 is a front view of the tapered bush.

FIG. 3 is a side sectional view of the same.

FIG. 4 is a half sectional view of a main part showing another embodiment of the impeller fixing structure in the canned motor pump according to the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a front view of the tapered bush.

FIG. 7 is a side sectional view of the same.

FIG. 8 is a half sectional view of a main part of a conventional canned motor pump.

FIG. 9 is an enlarged sectional view of a portion B of FIG. 8 showing the impeller fixing structure.

FIG. 10 is a sectional view showing another example of the impeller fixing structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Canned motor pump 2 Canned motor part 3 Pump part 6 Shaft 6a End part 7 Impeller 12 Thrust washer 13 Shaft sleeve 13a End face 14 Stepped part 15 Boss part 15b, 15c End face 16, 17 Key groove 18 Key 19 Washer assembly 21 Impeller bolt 25 Tapered bush 25a Cylindrical surface 25b Tapered surface 26 Slit 30 Tapered hole 32 Tapered bush 32a Cylindrical surface 32b Tapered surface 33 Flange 33a End surface 34 Tapered hole 35 Slit

Claims (5)

[Claims] A boss portion of an impeller is fixed to an end of a shaft rotatably supported by a bearing in the canned motor portion located in the pump portion by tightening an impeller bolt. In the canned motor pump, a cylindrical step is formed at the end of the shaft, and a tapered hole having a predetermined gap with respect to the step of the shaft is formed at the boss of the impeller. Between the tapered hole and the step portion of the shaft, the outer peripheral surface was formed with a tapered surface corresponding to the tapered hole of the boss portion of the impeller, and the inner peripheral surface was formed with a cylindrical surface corresponding to the outer peripheral surface of the step portion of the shaft. An impeller fixing structure in a canned motor pump, wherein an impeller is fixed to a shaft with a taper bush interposed. 2. The impeller fixing structure in a canned motor pump according to claim 1, wherein said taper bush is formed with a slit communicating with an inner and outer peripheral surface in an axial direction. 3. The tapered surface of the tapered bush, when the impeller is fixed to the end of the shaft via the tapered bush by tightening the impeller bolt, the end surface of the boss portion of the impeller on the side opposite to the impeller bolt mounting side is formed by the shaft. The impeller fixing structure for a canned motor pump according to claim 1 or 2, wherein the taper angle is set so as to be able to contact an end face of the shaft sleeve inserted into the shaft sleeve. 4. The tapered bush has a tapered surface formed of a tapered surface having a diameter decreasing toward the impeller bolt side, and a large-diameter flange portion formed at an end opposite to the impeller bolt side. The impeller and the shaft are positioned and fixed in the axial direction via a taper bush by contacting an end surface of a flange portion with an end surface of a shaft sleeve inserted into the shaft. Impeller fixing structure for canned motor pumps. 5. A taper bush, wherein a width of a slit formed in an axial direction of the key is fitted in a taper hole of a boss portion of the impeller and a key groove formed in an outer peripheral surface of a step portion of a shaft. The impeller fixing structure for a canned motor pump according to claim 4, wherein the width is set to be larger than the width of the impeller.