JPH0849686A - Submerged pump - Google Patents

Abstract

PURPOSE:To mount a motor cover made of synthetic resin in a watertight state on an upper bracket without the occurrence of creep deformation. CONSTITUTION:When a stepped bolt 50 screw-coupled to an upper bracket 30 arranged in such a manner to cover the upper part of a motor therewith is inserted in each through-hole 43a of a motor cover made of synthetic resin, the upper screw part 51 of each stepped bolt 50 is brought into a state to protrude upward from the through-hole 43a. With this state, a nut member is screw- coupled to the upper screw part of the stepped bolt. The nut member is forced into pressure contact with a stepped part between the upper screw part 51 of the stepped bolt 50 and an intermediate part 53. A packing 46 embedded in the lower part of a motor cover is forced into pressure contact with the upper bracket 30 in such a state that the lower part thereof is protruded from the motor cover.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submersible pump which is disposed in wastewater such as in a wastewater pit and is used for drawing up the wastewater.

[0002]

2. Description of the Related Art A submersible pump used for sucking and discharging sewage in a sewage pit together with waste is usually provided with a motor for rotating an impeller above a pump casing in which the impeller is arranged. The pump casing and the motor are used while being immersed in dirty water or the like.

In such a submersible pump, a portion of the impeller, the pump casing, the stator casing of the motor, the motor cover, etc., which comes into contact with the dirty water is excellent in corrosion resistance so as not to be corroded even when immersed in the dirty water. It is implemented by using stainless steel or by lining the steel material with rubber.

However, the stainless steel used for the impeller and the pump casing is not easy to process, and
There is a problem of being expensive. Further, when lining a steel material with a rubber, there is a problem that manufacturing is troublesome and economical efficiency is impaired, and further, there is a problem that the rubber lined with the steel material is difficult to repair once worn.

For such a submersible pump, for example,
In Japanese Utility Model Laid-Open No. 5-154590, only a motor stator casing (motor frame) is made of stainless steel, and a motor cover (head cover) attached to the upper side of the stator casing, a pump casing attached to the lower side of the stator casing, etc. There is disclosed a submersible pump which is made of synthetic resin. Such a submersible pump is relatively inexpensive and has excellent corrosion resistance, and further, synthetic resin parts can be easily replaced even when they are worn. .

In the submersible pump disclosed in the above publication, an upper bracket made of synthetic resin is fitted on the upper part of the stator casing, and a motor cover made of synthetic resin is arranged on the upper side of the upper bracket. There is. The synthetic resin upper bracket and the motor cover are connected by a plurality of embedded bolts and nuts embedded in the upper bracket.

Each embedded bolt embedded in the upper bracket is in a state of projecting upward from the upper bracket, and the packing and the motor cover are inserted into each embedded bolt to project the embedded bolt projecting above the motor cover. The nut is screwed to the top of the. In this case, a nut screwed to the embedded bolt is pressed against the motor cover and tightened so that the motor cover and the upper bracket are watertight by packing.

[0008]

As described above, when the nut screwed to the embedded bolt is tightened so as to be pressed against the motor cover made of synthetic resin, a large stress is applied to the motor cover. . If the stress applied to the synthetic resin motor cover is large, the motor cover may undergo creep deformation. If the motor cover undergoes creep deformation, the tightening force of the embedded bolt and nut will decrease and the nut will loosen.

The creep deformation of the synthetic resin is promoted as the temperature rises, and a large creep deformation occurs. Since the motor cover is located above the motor, even when the motor is immersed in water, the motor cover receives heat from the motor and becomes hot. Moreover, the motor cover located above the motor is not always immersed in water, and when it is temporarily exposed to the water, the amount of heat radiation is drastically reduced and the temperature becomes high. In such a motor cover made of synthetic resin which is likely to reach a high temperature, creep deformation may be promoted and the nut may loosen. When the nut is loosened, the motor cover is not pressed against the upper bracket, and as a result, the watertight state is not maintained due to the packing interposed therebetween, and water may enter the motor.

The present invention solves such a problem and an object thereof is to prevent creep deformation by preventing stress from being applied to a synthetic resin motor cover which is apt to cause creep deformation at high temperature. It is intended to provide a submersible pump capable of firmly attaching the motor cover to the upper bracket in a watertight state by suppressing the above.

[0011]

The submersible pump of the present invention comprises:
A pump casing in which an impeller is arranged, a motor arranged above the pump casing so as to drive the impeller to rotate, and a motor casing arranged so as to cover the upper end portion of the motor, and a flange portion is provided on the peripheral portion. The upper bracket provided and a small-diameter screw part are provided coaxially in the upper part and the lower part with a large-diameter middle part sandwiched therebetween, and the lower screw part is circumferentially provided on the flange part of the upper bracket. A plurality of stepped bolts that are screw-coupled at points, and a plurality of through holes that are arranged on the upper side of the upper bracket and through which the stepped bolts are inserted so that the upper threaded portion protrudes upward. The motor cover made of synthetic resin with the pedestal at the peripheral edge, and the screw on the upper part of the stepped bolt projecting upward from the through hole in each pedestal of this motor cover. The nut member is joined and press-contacted with the stepped portion between the upper screw portion and the intermediate portion, and is pressed against the upper surface of the flange portion of the upper bracket while protruding from the lower surface of the motor cover over the entire circumference. And a packing embedded in the lower portion of the motor cover, whereby the above object is achieved.

[0012]

In the submersible pump of the present invention, when each stepped bolt screwed to the upper bracket arranged so as to cover the upper portion of the motor is inserted into the through hole of the motor cover made of synthetic resin, each stepped bolt is inserted. The upper threaded portion of the stud bolt protrudes upward from the through hole. At this time, the packing embedded in the lower portion of the motor cover is in contact with the upper surface of the upper bracket while protruding downward from the lower surface of the motor cover.

In this state, the nut member is screwed to the upper threaded portion of the stepped bolt. The nut member is pressed into contact with the stepped portion between the upper screw portion and the intermediate portion of the stepped bolt and tightened. Therefore, the motor cover made of synthetic resin is not likely to be stressed when the nut member is tightened. When the nut member is tightened to the stepped bolt, the packing projecting downward from the motor cover is pressed against the upper bracket, and the space between the motor cover and the upper bracket is kept watertight by the packing.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a partially cutaway front view of the submersible pump of the present invention, and FIG. 2 is a plan view of the submersible pump.

This submersible pump is used, for example, to pump up sewage containing filth, foreign matter, etc., and stored water at a construction site. This submersible pump has a pump casing 10 in which an impeller 12 is arranged, and a motor 20 arranged above the pump casing 10.

The motor 20 has a cylindrical stator casing 22 having an axial center in a vertical state, a rotor 23 attached to a rotary shaft 24 which passes through the axial center portion of the stator casing 22, and a rotor 23 surrounding the rotor 23. Thus, the stator 24 is attached to the inner surface of the stator casing 22.

At the lower end of the stator casing 22,
A disk-shaped lower bracket 26 is fitted, and the lower bracket 26 has a proper space formed around the rotary shaft 24 between the lower casing 26 and the upper surface of the lower pump casing 10. Covers the lower end of the.

The rotary shaft 24 penetrates the lower bracket 26, extends through the space between the lower bracket 26 and the pump casing 10, and extends inside the pump casing 10. The rotating shaft 24 is rotatably supported by a bearing 27 with respect to a lower bracket 26.

The pump casing 10 has an upper case 14 and a lower case 15 each made of synthetic resin, and the upper case 14 and the lower case 1 are provided.
The inside of 5 is a pump chamber 16.

The upper case 14 and the lower bracket 26 fitted to the bottom surface of the stator casing 22 have a peripheral portion of the upper case 14 and the lower bracket 26 so that an appropriate space is formed around the rotary shaft 24. The peripheral part of
It is connected by a bolt 29.

Further, a mechanical seal 28 for sealing the periphery of the rotary shaft 24 is attached between the upper case 14 and the lower bracket 26.

The lower end of the rotary shaft 24 passes through the upper case 14 and enters the pump chamber 16 inside the pump casing 10, and the rotary shaft 24 located in the upper case 14 is located in the pump chamber 16.
An impeller 12 is attached to the lower end of the.

The upper case 14 and the lower case 15 are integrally connected by a plurality of nuts and bolts (not shown) with the packing 17 sandwiched therebetween.

The upper case 14 and the lower case 15 are respectively provided with discharge pipe line portions 14a and 15a which linearly extend outward from the pump chamber 16, and the discharge pipe line portions 14a and 15a are respectively formed. It communicates with the pump chamber 16.

A suction port 15b is formed on the bottom surface of the lower case 15 so as to face the rotary shaft 24, and a plurality of circumferential bottom surfaces of the lower case 15 support the bottom surface of the lower case 15. Each leg 18 is provided.

In the discharge pipe line portion 14a of the upper case 14,
As shown in FIG. 2, a discharge port 14b having an opening on the upper surface is provided. A discharge pipe mounting flange 13 is arranged on the upper surface of the discharge pipe passage portion 14 a with a packing 19 interposed therebetween. The discharge pipe mounting flange 13 includes a pair of bolts 1
1 is integrally attached to the upper case 14.

At the upper end of the stator casing 22,
As shown in FIG. 1, a disc-shaped upper bracket 30 made of synthetic resin is fitted. The upper bracket 30 covers the upper end of the stator casing 22, and a bearing 31 is attached to the axial center of the upper bracket 30. The upper end of the rotary shaft 24 is rotatably supported by the bearing 31. A flange portion 34 that is in contact with the stator casing 22 is provided on the outer peripheral portion of the upper bracket 30, and on the flange portion 34,
A motor cover 40 made of synthetic resin that accommodates electrical components inside is mounted in a mounted state.

The motor cover 40 has a cylindrical peripheral surface portion 41 (see FIG. 1) whose upper surface 42 is closed, and a grip portion 49 is provided on the upper surface. This peripheral surface part 4
1 is in a state of being recessed inward at four locations that are equally spaced in the circumferential direction, and is mounted on the flange portion 34 of the upper bracket 30 at the lower end of each recessed portion. A pedestal portion 43 is provided. Each pedestal portion 43 is provided with a through hole 43a extending in the vertical direction, and the flange portion 34 of the upper bracket 30 has four bolt holes 34a in the circumferential direction corresponding to each through hole 43a. They are provided at equal intervals. Each bolt hole 34 provided in the flange portion 34 of the upper bracket 30
The diameter a is smaller than each through hole 43a provided in each pedestal portion 43 of the motor cover 40, and has a thread groove on the inner peripheral surface. The bolt holes 34a and the through holes 43a are concentric with each other.

FIG. 3 is a sectional view of the essential parts of the motor cover 40 and the upper bracket 30. Motor cover 4
On the lower end surface of 0, an annular groove 45 opened downward is formed over the entire circumference, and a packing 46 is fitted in the annular groove 45.

FIG. 4 is a plan view of an essential part of the packing 46 fitted in the annular groove 45, and FIG. 5 is a sectional view taken along the line AA of FIG. The annular groove 45 is inwardly spread at each pedestal portion 43. The packing 46 also has the same shape as the annular groove 45, and has an annular packing body 46a that is continuous over the entire circumference and four projecting portions 46b that fit into the inwardly extending portions of each pedestal portion 43. are doing. Each protruding portion 46b is provided with a through hole 46c extending vertically.

In the packing 46 having such a structure, the vertical length (thickness) H is the vertical length D of the annular groove 45.
(See FIG. 7) The length is slightly longer than that of the motor cover 4 when fitted in the annular groove 45 in a close contact state.
It is designed to project from the lower surface of 0 over the entire circumference.

Motor cover 40 and upper bracket 30
And are connected by a stepped bolt 50. Figure 6
FIG. 4 is a front view of the stepped bolt 50. The stepped bolt 50 is made of stainless steel, and has an upper threaded portion 51 and a lower threaded portion 52, each having a small diameter and having a thread groove formed on the outer peripheral surface, at both ends. Upper screw part 5
An intermediate portion 53 having a diameter larger than that of each of the screw portions 51 and 52 is coaxially arranged between the 1 and the lower screw portion 52. A step portion 54 is provided between the upper screw portion 51 and the intermediate portion 53.
Are formed.

In such a stepped bolt 50, as shown in FIG. 3, the lower screw portion 52 is screwed into the bolt hole 34a provided in the flange portion 34 of the upper bracket 30, and the motor cover 40 is provided. Through hole 43a provided in the pedestal portion 43 and through hole 46c of the packing 46
The intermediate portion 53 is inserted therein. In such a state, the upper screw portion 51 projects above the pedestal portion 43, and the upper screw portion 5 that projects above the pedestal portion 43 of the motor cover 40.
The plain washer 61 is fitted to the screw 1, and the cap nut 62 is screwed. The cap nut 62 is a flat washer 61
It is fastened to the stepped bolt 50 by being pressed into contact with the step portion 54 of the stepped bolt 50 via.

FIG. 7 is a sectional view of the essential parts of the motor cover 40 and the upper bracket 30 with the packing 46 removed. The length of the intermediate portion of the stepped bolt 50 is longer than the vertical length of the pedestal portion 43 of the upper bracket 40 by the length indicated by C in FIG. 7. The packing 46 fitted in the annular groove 45 is longer than the length of the annular groove 45 in the vertical direction by a length L (see FIG. 3) equal to the length C described above and a tightening margin. There is.

In the submersible pump having such a structure, the motor cover 40 is attached to the upper bracket 30 as follows. First, the lower screw portions 52 of the stepped bolts 50 are screwed into the respective bolt holes 34a provided in the bracket portion 34 of the upper bracket 30. In each stepped bolt 50, the step between the lower screw portion 52 and the intermediate portion 53 is in contact with the upper surface of the upper bracket 30. Then, attach the motor cover 4 to each stepped bolt 50.
The through hole 43a provided in each pedestal portion 0 of 0 is fitted. At this time, an annular packing 46 is fitted in the annular groove 45 of the motor cover 40, and the pedestal portion 4
3, the protruding portions 46b of the packing 46 are positioned.

When each through hole 43a in the pedestal portion 43 of the motor cover 40 is fitted into each stepped bolt 50,
Since the vertical length H of the packing 46 is longer than the vertical length (depth) D of the annular groove 45, the protruding portion 46b of the packing 46 extends downward from the lower surface of the pedestal portion 43. It is in a state of protruding by L (= C) and a tightening margin. Then, each protrusion 4 of the packing 46
The lower surface of 6b comes into contact with the upper surface of the flange portion 34 of the upper bracket 30.

In this state, the flat washer 61 is fitted to the upper screw portion 51 of each stepped bolt 50 protruding upward from each pedestal portion 43, and the cap nut 62 is screwed. Then, by tightening the cap nut 62,
The flat washer 61 is pressed against the step portion 54 between the upper screw portion 51 and the intermediate portion 53 of the stepped bolt 50, and the packing 46 is in a state of being contracted by the tightening margin.

The intermediate portion 53 of the stepped bolt 50 is longer by the length C than the vertical length of the pedestal portion 43, but the packing 46 fitted in the annular groove 45 of each pedestal portion 43 is , The length C (= L) from the lower surface of each pedestal portion 43
When the cap nut 62 abuts the stepped portion 54 between the upper threaded portion 51 and the intermediate portion 53 of the stepped bolt 50 through the flat washer 61, since it is in a state of protruding downward only by
By the repulsive force of the packing 46 pressed against the upper surface of the upper bracket 30, the entire motor cover 40 is lifted up, and the upper surface of each pedestal portion 43 has a flat washer 61.
Is in contact with. In such a state, as shown in FIG. 3, each protruding portion 46b of the packing 46 is pressed against the upper surface of the upper bracket 30 while protruding downward from the lower surface of each pedestal portion 43 by the length L. .

As described above, when the cap nut 62 is screwed to the stepped bolt 50 and tightened, no stress is applied to the motor cover 40 made of synthetic resin, and the motor cover 40 is not susceptible to creep deformation. . The motor cover 40 has a flat washer 6 with a weak force due to the packing 46 pressed against the flange portion 34 of the upper bracket portion 30.
It is only pressed against 1, so there is no risk of creep deformation due to the pressing force. In addition, between the upper bracket 30 and the motor cover 40, the packing 46 protruding by the length L from the motor cover 40 is pressed against the flange portion 34 of the upper bracket portion 30. Cover 4
0 and the upper bracket 30 are kept watertight, and there is no possibility that water will enter the motor 20 from between the motor cover 40 and the upper bracket 30.

[0041]

According to the submersible pump of the present invention, the stepped bolt screwed to the upper bracket and the packing attached to the motor cover thus prevent the motor cover from being stressed. It can be pressed onto the upper bracket through the packing. As a result, there is no risk of creep deformation of the synthetic resin motor cover, and there is no risk of loosening of the nut screwed to the stepped bolt. Since the motor cover is in pressure contact with the upper bracket through the packing with the stepped bolts and nuts, the watertight state is maintained between the motor cover and the upper bracket, and water is not stored in the motor. There is no risk of infiltration.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an example of a submersible pump of the present invention.

FIG. 2 is a plan view of the submersible pump.

FIG. 3 is a vertical sectional view of a main part of the submersible pump.

FIG. 4 is a plan view showing a main part of packing used in the submersible pump.

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

FIG. 6 is a front view of a stepped bolt used in the submersible pump.

FIG. 7 is an explanatory view showing a state where the packing is removed from the main part of the submersible pump shown in FIG.

[Explanation of symbols]

 10 pump casing 12 impeller 20 motor 22 stator casing 23 rotor 24 rotating shaft 25 stator 30 upper bracket 40 motor cover 34 flange part 41 peripheral surface 43 pedestal part 43a through hole 45 annular groove 46 packing 50 stepped bolt 51 upper screw part 52 Lower screw part 53 Middle part 61 Washer 62 Cap nut

Front page continuation (72) Inventor Shuji Iwakami 6-10 Takino-cho, Nishinomiya-shi, Hyogo Shinmeiwa Industry Co., Ltd. Development Technology Headquarters (72) Katsunori Noda 6-107 Takino-cho, Nishinomiya-shi, Hyogo Shinmeiwa Industry Co., Ltd.

Claims (1)

[Claims] 1. A pump casing in which an impeller is arranged, a motor arranged above the pump casing so as to rotationally drive the impeller, and a peripheral portion which is arranged so as to cover an upper end portion of the motor. The upper bracket is provided with a flange part on the upper part, and the small-diameter screw part is provided coaxially on the upper part and the lower part with the large-diameter middle part sandwiched in between, and the lower screw part is the flange part of the upper bracket. A plurality of stepped bolts that are screwed together at a plurality of positions in the circumferential direction, and a through bolt that is arranged on the upper side of the upper bracket and through which the stepped bolts are inserted so that the upper threaded portion protrudes upward. A motor cover made of synthetic resin having a plurality of pedestals each having a hole at the peripheral edge thereof, and a stepped bolt protruding upward from a through hole in each pedestal of the motor cover. Nut member that is screwed to the screw portion of the upper portion and is pressed against the step portion between the upper screw portion and the intermediate portion, and the upper surface of the flange portion of the upper bracket in a state of protruding from the lower surface of the motor cover over the entire circumference. A submersible pump comprising: a packing embedded in the lower part of the motor cover so as to be pressed against the.