JPH09280191A - Submergible pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely shaft-seal the end part of a rotor shaft for inserting a bracket, by a pair of oil seals arranged in the given position of the bracket. SOLUTION: A rotor shaft 24, for inserting the axis part of a motor 20, inserts a bracket 29 for covering the lower end surface of the motor 20, and an impeller 31, arranged in a pump casing 35, is fitted to the lower end part of the bracket 29. An upper seal fittedly engaging part 29c and a lower seal fittedly engaging part 29d having an inner diameter larger than that of the engaging part 29c are provided with connected vertically on the center part of the bracket 29, and a different level part 29f is formed between both the sides. Upper and lower oil seals 27 and 28 are pressed into the engaging parts 29c and 29d respectively. A clearance is formed between the oil seals 27 and 28, and is filled with grease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relatively small submersible pump used for sprinkling water such as plants in a garden at home or for draining and circulating accumulated water.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a relatively small submersible pump used at home for purposes such as watering garden plants. In this submersible pump, a motor 62 is usually covered with a plastic head cover 61. The lower end surface of the motor 62 has a bracket 63 made of aluminum or plastic.
The lower end portion of the rotor shaft 64 that is inserted through the shaft center portion of the motor 62 extends below the bracket 63. An impeller 66 disposed inside the pump casing 65 is attached to the lower end of the rotor shaft 64, and the pump casing 65 is covered by a strainer 67.

In the submersible pump having such a structure, when the impeller 66 is rotated by driving the motor 62, the fluid is sucked into the pump casing 65. The fluid sucked into the pump casing 65 is
It flows upward through the inside of the flow path 61a provided inside in the vertical direction. A hose coupling 68 to which an end of a hose (not shown) is attached is attached to the discharge port provided at the upper end of the flow passage 61a, and the fluid flowing upward in the flow passage 61a is It is discharged through the discharge port into the hose attached by the hose coupling 68.

A bracket 6 for covering the lower end surface of the motor 62
3 has a cylindrical boss 63 protruding upward in the center.
a is provided, and in the upper end of the boss 63a,
Bearing 63 for rotatably supporting rotor shaft 64
b is supported in a fitted state. Further, in the boss portion 63a, a pair of oil seals 63 is provided below the bearing 63b.
c and 63d are arranged side by side in the vertical direction.
The oil seals 63c and 63d are pressed against the outer peripheral surface of the rotor shaft 64 that is inserted through the boss portion 63a to seal the rotor shaft 64.

FIG. 4A shows the boss portion 6 of the bracket 63.
3a is a sectional view, and FIG. 4 (b) is a sectional view of the boss portion 63a with the oil seals 63c and 63d removed. A seal fitting portion 6 in which a pair of oil seals 63c and 63d are fitted to the boss portion 63a of the bracket 63.
3e is provided below the bearing 63b, and a pair of oil seals 63c and 63d are continuously press-fitted in the seal fitting portion 63e in the vertical direction so as to contact each other. The oil seals 63c and 63d have the same outer diameter.

Further, as shown in FIG. 5, a ring-shaped spacer 63f is interposed so that an appropriate gap is formed between the oil seals 63c and 63d, and the gap is filled with grease. Then, each oil seal 63c
And a method of improving the durability of 63d are also implemented.

[0007]

The boss portion 63a of the bracket 63 is usually a cylinder provided with a seal fitting portion 63e by die casting when it is made of aluminum and by injection molding when it is made of plastic. It is molded into a shape. As described above, when the boss portion 63a of the bracket 63 is formed by die casting or injection molding, since the die is provided with a draft for facilitating the die cutting, the boss portion 63a is formed in the boss portion 63a. The inner peripheral surface of the seal fitting portion 63e is tapered so that the inner diameter becomes smaller toward the upper side.

Although the taper angle formed on the inner peripheral surface of the seal fitting portion 63e is small, the seal fitting portion 63e is small.
Is relatively long in the axial direction so that the pair of oil seals 63c and 63d can be fitted, the difference between the inner diameter of the upper end portion and the inner diameter of the lower end portion becomes large. In such a seal fitting portion 63e, a pair of oil seals 63 having the same outer diameter is provided.
When press-fitting c and 63d, the oil seal 63c arranged on the upper side is tightly tightened by the inner peripheral surface of the seal fitting portion 63e and press-fits to a predetermined position of the upper end portion in the seal fitting portion 63e. The problem is that it is not easy. Further, the oil seal 63d arranged on the lower side may not be strongly pressed by the lower end portion of the seal fitting portion 63e and may not be strongly pressed on the outer peripheral surface of the rotor shaft 64. In a state where the oil seal 63d is not strongly pressed against the outer peripheral surface of the rotor shaft 64, the oil seal 63d causes creep due to the rotation of the rotor shaft 64, and
It becomes impossible to securely seal the shaft.

The same problem occurs when a ring-shaped spacer 63f is interposed between the oil seals 63c and 63d.

For this reason, after the seal fitting portion 63a provided in the boss portion 63a is molded, the inner peripheral surface is mechanically processed so that the tapered state is eliminated and the inner diameter becomes constant. Is carried out. However, in this case, there is a problem that the machining is required after the boss portion 63a is formed, and the work is troublesome.

The present invention solves such a problem, and an object thereof is to eliminate the need for mechanical processing of the boss portion of the bracket after it has been molded, and to provide a pair of boss portions provided on the boss portion. An object of the present invention is to provide a submersible pump capable of reliably sealing the rotor shaft with an oil seal. Another object of the present invention is to provide a submersible pump capable of stably sealing the rotor shaft for a long period of time with a pair of oil seals.

[0012]

In the submersible pump according to claim 1, an impeller arranged in a pump casing is attached to a lower end portion of a rotor shaft which is inserted through an axial center portion of a motor. The submersible pump in which the fluid flowing into the pump casing is discharged upward by the rotation of the impeller, and the rotor shaft inserted through the central portion of the bracket covering the lower end surface of the motor is at least It is characterized in that it is axially sealed by an upper oil seal and a lower oil seal arranged vertically, and the outer diameter of the lower oil seal is larger than the outer diameter of the upper oil seal.

In the submersible pump according to a second aspect of the present invention, an upper seal fitting portion into which the upper oil seal is press-fitted and a lower oil seal are press fit into the center portion of the bracket. And a lower seal fitting portion having an inner diameter larger than the inner diameter of the upper seal fitting portion and the lower seal fitting portion are continuously provided vertically, and a step is formed between the upper seal fitting portion and the lower seal fitting portion.

In the submersible pump according to a third aspect of the present invention, a gap is provided between the upper oil seal and the lower oil seal, and the gap is filled with grease.

In the submersible pump according to a fourth aspect, the rotor shaft is further axially sealed by one or a plurality of oil seals.

[0016]

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

FIG. 1 is a vertical sectional view showing an example of an embodiment of the submersible pump of the present invention.

This submersible pump comprises a frustoconical head cover 10 which becomes narrower toward the upper side, a motor 20 arranged inside the head cover 10, and a pump casing 35 provided below the motor 20. Have

The motor 20 has a cylindrical stator casing 21 and a stator 22 having a hollow axial center portion, which is arranged concentrically in the stator casing 21.
And The stator 22 is fixed to the inner peripheral surface of the stator casing 21. In the hollow shaft center of the stator 22, the rotor 23 is concentric,
It is rotatably fitted. The rotor shaft 24 is inserted through the axial center of the rotor 23, and the upper end and the lower end of the rotor shaft 24 extend above and below the rotor 23, respectively.

The stator casing 21 has an upper end surface 21.
A is in a closed state, and a boss portion 21c protruding downward is provided at the center thereof.
The upper end of the rotor shaft 24 is inserted into the boss 21c, and the upper end of the rotor shaft 24 inserted into the boss 21c is rotatably supported by the bearing 25.

The upper end surface 21a of the stator casing 21
A condenser 21f is installed in the. Further, the upper end surface 21a of the stator casing 21 is provided with a cable insertion hole 21k through which a power feeding cable 44 for the motor 20 is inserted and a screw hole 21h for attaching a ground wire to the motor 20.

The lower end surface of the stator casing 21 is open and closed by abutting aluminum brackets 29. The bracket 29 has a diameter larger than that of the stator casing 21, and an outer peripheral portion thereof is in a state of horizontally extending outside the stator casing 21 over the entire circumference. On the outer peripheral portion of the bracket 21, one discharge opening 29b is provided. Further, the outer peripheral portion of the bracket 29 is butted against the plastic head cover 10 that covers the motor 20.
Are stopped by bolts 12.

The head cover 10 is formed in a truncated cone shape that tapers toward the upper side, and its upper end surface is flat.

Inside the head cover 10, there is provided a flow path 13 extending linearly upward from the discharge opening 29b of the bracket 29. The flow path 13 is the head cover 1
0 is connected to the discharge port 14 provided in the upper part, and a screw groove 14a is provided on the outer peripheral surface of the discharge port 14.
A hose coupling 43 is abutted on the upper end surface of the discharge port 14 via a packing 42, and the hose coupling 43 is discharged by a nut member 41 screwed to a thread groove 14 a of the discharge port 14. It is attached to 14. The end of the hose is attached to the hose coupling 43.

A grip portion 15 is provided on the flat upper end surface of the head cover 10 so as to project upward, and the discharge port 1 on the upper end surface of the head cover 10 is provided.
The cable mounting seat 16 is provided at a centrally symmetrical position with the grip portion 15 sandwiched between the cable mounting seat 16 and the cable mounting seat 16. The cable mounting seat 16 includes a capacitor 21 provided on the upper end surface 21 a of the stator casing 21.
f, a cable 44 for supplying power to the motor 20, etc.
The end of is attached.

A partition wall 17 is provided at the upper end of the head cover 10 and projects downward from the upper end surface in a cylindrical shape. The partition wall portion 17 surrounds the condenser 21f provided on the upper end surface 21a of the stator casing 21, and is pressed against the outer peripheral edge portion of the upper end surface 21a of the stator casing 21 in a watertight state.

A boss portion 29a protruding upward is provided at the center of the bracket 29, and the boss portion 29a is provided.
A rotor shaft 24 is inserted through which the shaft center of the motor 20 is inserted. The rotor shaft 24 is in a state of extending below the bracket 29. The rotor shaft 24 is rotatably supported by a bearing 26 provided in the boss portion 29a. Boss part 29
Inside a, an upper oil seal 27 and a lower oil seal 28 are provided below the bearing 26 side by side in the vertical direction.

FIG. 2A shows the boss portion 2 of the bracket 29.
9A is a cross-sectional view of FIG. 2B, showing the boss portion 2 with the upper oil seal 27 and the lower oil seal 28 removed.
9a is a sectional view of FIG.

A boss 29a provided at the center of the disk-shaped bracket 29 projects upward in a cylindrical shape, and the tip end thereof has a bearing fitting portion 29e into which the bearing 26 is fitted. Is provided, and this bearing fitting portion 29e
A bearing 26 is fitted therein.

Bearing fitting portion 29e in boss portion 29a
An upper seal fitting portion 29c and a lower seal fitting portion 29d are continuously provided in the lower part of the vertical direction.
A rib 29h is provided between the bearing fitting portion 29e and the upper seal fitting portion 29c so as to project horizontally inward from the inner peripheral surface of the boss portion 29a. The bearing 26 fitted to the
It is in a state of being hit against.

The upper seal fitting portion 29c has an inner diameter substantially equal to the inner diameter of the upper bearing fitting portion 29e, and the inner diameter of the lower seal fitting portion 29d is the upper seal fitting portion 29e.
It is slightly larger than the inner diameter of c. Therefore, a step portion 29f is formed between the upper seal fitting portion 29c and the lower seal fitting portion 29d.

An annular upper oil seal 27 is press-fitted in a watertight manner into the upper seal fitting portion 29c.
An annular lower oil seal 28 is also press-fitted in a watertight manner in the lower seal fitting portion 29d. The upper oil seal 27 press-fitted into the upper seal fitting portion 29c has an axial length slightly shorter than the axial length of the upper seal fitting portion 29c, and is provided between the upper oil seal 27 and the bearing fitting portion 29e. The ribs 29h are abutted against each other. Therefore, the upper oil seal 27 is located slightly above the step portion 29f. The axial length of the lower oil seal 28 press-fitted into the lower seal fitting portion 29d is slightly shorter than the axial length of the lower seal fitting portion 29d, and a step portion with the upper seal fitting portion 29c is formed. It is hit against 29f. Therefore, between the lower oil seal 28 and the upper oil seal 27, which are abutted against the step 29f,
A gap 29g is formed, and grease is filled in the gap 29g.

The rotor shaft 24, through which the boss portion 29a of the bracket 29 is inserted, is rotatably supported by the bearing 26, and is in a state in which the axial center portions of the annular upper oil seal 27 and the lower oil seal 28 are inserted. ing. The upper oil seal 27 and the lower oil seal 28 are water-tightly pressed against the outer peripheral surface of the rotor shaft 24 to seal the rotor shaft 24.

As shown in FIG. 1, an impeller 31 is attached to the lower end of the rotor shaft 24 extending downward from the bracket 29. The impeller 31 is arranged in a pump casing 35 attached to the lower side of the bracket 29. The pump casing 35 is in a state of being abutted with the lower end portion of the head cover 10 fitted to the bracket 29 via a rubber band 36. A suction port 32 is provided on the bottom surface of the pump casing 35, and the rotation of the impeller 31 allows the fluid to be sucked into the pump casing 35 through the suction port 32. The fluid sucked into the pump casing 35 flows into the flow passage 13 of the head cover 10 through the flow passage portion 33 provided on the outer peripheral side of the pump casing 35 and the discharge opening portion 29b of the bracket 29, The liquid is discharged from the discharge port 14 at the upper end of the flow path 13.

The pump casing 35 is covered by a cylindrical strainer 34 on its peripheral surface and bottom surface except the upper end. The bottom surface of the strainer 34 is in a closed state, and a large number of elongated holes (not shown) extending in the vertical direction are provided on the circumferential surface of the strainer 34 at equal intervals in the circumferential direction.

In the submersible pump having such a structure, when the rotor shaft 24 is rotated by the rotation of the rotor 23 of the motor 20, the impeller 31 in the pump casing 35 is rotated to pass through the elongated holes of the strainer 34. The fluid then flows into the pump casing 35.

The fluid flowing into the pump casing 35 becomes a vortex due to the centrifugal force generated by the rotation of the impeller 31, passes through the flow passage portion 33 of the pump casing 35, and flows into the flow passage 13 provided in the head cover 10. . Then, the fluid flowing into the flow path 13 flows upward through the flow path 13 and is discharged from the discharge port 14 provided at the upper end of the flow path 13. The outlet 14 has a hose coupling 43.
The end of the hose is connected by the
The fluid discharged from the discharge port 14 is caused to flow to a predetermined position by the hose and then discharged from the hose.

An upper seal fitting portion 29c and a lower seal fitting portion 29d having different inner diameters are provided on the boss portion 29a of the bracket 29 through which the rotor shaft 24 is inserted, and the upper seal fitting portion 29c has an upper portion. The oil seal 27 is press-fitted and the lower seal fitting portion 2
The lower oil seal 28 is press-fitted into 9d. Therefore, the upper seal fitting portion 29c and the lower seal fitting portion 2
9d has an upper seal fitting portion 29c even if each of them is formed in a tapered shape in order to die-cut the boss portion 29a.
Also, the axial length of the lower seal fitting portion 29d is relatively short, and the difference in inner diameter between the upper end surface and the lower end surface of each is very small. For this reason, the upper oil seal 27 and the lower oil seal 28 are not required to be machined to eliminate the tapered state of the inner peripheral surfaces of the upper seal fitting portion 29c and the lower seal fitting portion 29d. The seal fitting portion 29c and the lower seal fitting portion 29b are securely mounted in a predetermined pressure contact state, respectively, and
The outer peripheral surface of the rotor shaft 24 is firmly pressed against each other. As a result, the upper oil seal 27 and the lower oil seal 28 can reliably seal the lower end of the rotor shaft 24.

A gap 29g is formed between the upper oil seal 27 and the lower oil seal 28 without providing a spacer or the like, and the gap 29g is filled with grease. Therefore, the upper oil seal 27
The lower oil seal 28 and the lower oil seal 28 have improved durability due to grease, and can stably seal the rotor shaft 24 for a long period of time.

In the above-mentioned embodiment, the rotor shaft 24 is axially sealed by the upper oil seal 27 and the lower oil seal 28. An oil seal may be provided to seal the rotor shaft 24.

[0041]

As described above, in the submersible pump of the present invention, the rotor shaft is axially sealed by the pair of oil seals having different outer diameters. Even if the inner peripheral surface of the joint portion is slightly tapered, each oil seal can be securely attached at a predetermined position, and the rotor shaft can be surely sealed. In addition, each oil seal is press-fitted into the seal fitting portion having the inner diameter corresponding to the respective outer diameter, so that each oil seal can seal the rotor shaft more reliably. A gap can be formed between the oil seals by the stepped portion formed between the seal fitting portions. By filling the gap with grease, the oil seals can be stably maintained for a long period of time. The rotor shaft can be sealed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a submersible pump of the present invention.

FIG. 2A is a sectional view of a shaft-sealing portion of a rotor shaft of the submersible pump, and FIG. 2B is a sectional view of a shaft-sealing portion of the rotor shaft with an oil seal removed.

FIG. 3 is a partially cutaway front view showing an example of a conventional submersible pump.

FIG. 4A is a cross-sectional view of the shaft-sealing portion of the rotor shaft, and FIG. 4B is a cross-sectional view of the shaft-sealing portion of the rotor shaft with the oil seal removed.

FIG. 5 is a cross-sectional view showing another example of the shaft sealing portion of the rotor shaft.

[Explanation of symbols]

 10 Head Cover 12 Bolt 13 Flow Path 14 Discharge Port 15 Handle 16 Cable Mounting Seat 17 Partition 20 Motor 21 Stator Casing 22 Stator 23 Rotor 24 Rotor Shaft 25 Bearing 26 Bearing 27 Upper Oil Seal 28 Lower Oil Seal 29 Bracket 29a Boss 29c Upper seal fitting portion 29d Lower seal fitting portion 29f Step portion 29g Gap 31 Impeller 32 Suction port 34 Strainer 35 Pump casing

Claims (4)

[Claims] 1. An impeller arranged in a pump casing is attached to a lower end portion of a rotor shaft which is inserted through a shaft center portion of a motor, and a fluid flowing into the pump casing is caused by rotation of the impeller. A submersible pump that discharges upward, wherein a rotor shaft that penetrates a central portion of a bracket that covers a lower end surface of the motor has at least an upper oil seal and a lower oil seal that are vertically arranged. The submersible pump is characterized in that the outer diameter of the lower oil seal is larger than the outer diameter of the upper oil seal. 2. The center portion of the bracket has an upper seal fitting portion into which an upper oil seal is press-fitted, and an inner diameter larger than an inner diameter of the upper seal fitting portion so that a lower oil seal is press fit. The submersible pump according to claim 1, wherein the lower seal fitting portion is provided continuously in the vertical direction, and a step is formed between the upper seal fitting portion and the lower seal fitting portion. 3. The submersible pump according to claim 2, wherein a gap is provided between the upper oil seal and the lower oil seal, and grease is filled in the gap. 4. The submersible pump according to claim 1, wherein the rotor shaft is further axially sealed by one or more oil seals.