JP2002138986A - Motor pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact centrifugal (non-positive displacement type) motor pump being suitable for use in a region of a small output by an extremely small amount of water and having a comparatively simple structure. SOLUTION: In the motor pump in which liquid to be handled flows on an inner side of a cylindrical motor stator 10, a rotary flow passage 32 having the action for increasing a pressure of the liquid to be handled is provided inside a substantially circular columnlike motor rotor 30 arranged inside the motor stator 10 and having a permanent magnet 34 by passing through it in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor pump, and more particularly, to a motor pump using a motor (for example, a DC brushless motor) having a permanent magnet in a motor rotor, which is suitable for use in an area with a very small amount of water and a small output. It relates to a motor pump.

[0002]

2. Description of the Related Art In general, pumps incorporated in various devices and used at a flow rate of 1 liter or less per minute to several liters per minute use a positive displacement pump such as a gear pump or a diaphragm pump. Many. This is a region where the value of the specific speed Ns is an extremely small value in a centrifugal pump (a non-positive displacement pump), and this is partly because it is difficult to respond to a practical design. For example, a centrifugal pump with a flow rate of 1 liter per minute and a head of 10 meters is 1200
When designed at a rotation speed of 0 rotation, the value of the specific speed Ns is 67
(M ³ / min, m, min ⁻¹ ). In general, it is known that the efficiency of the centrifugal pump is significantly reduced when the value of the specific speed Ns becomes 70 or less, so that high efficiency cannot be expected. Moreover, at the design point, the outer diameter of the impeller is about 25 mm, and the blade width of the impeller is less than 1 mm,
For example, it is difficult to manufacture an impeller using a stainless steel casting.

[0003]

On the other hand, the gear pump is
Two shafts and two sets of bearings are required to rotate the two gears, which makes the structure more complicated and expensive than a centrifugal pump. In addition, the diaphragm pump is configured to repeatedly deform a non-metallic flexible diaphragm to feed liquid, and it is generally necessary to replace the diaphragm in operation for about several thousand hours. For this reason, when this kind of pump is used by being incorporated in various small devices, there is a problem that maintenance cost is excessively increased. For this reason, development of a centrifugal motor pump, which is suitable for use in an area with a very small amount of water and a small output, which replaces a positive displacement motor pump, has been strongly desired.

The present invention has been made in view of the above, and is suitable for use in an area having a very small amount of water and a small output, and has a relatively simple structure and a small size and a compact size. ) To provide a motor pump.

[0005]

According to a first aspect of the present invention, there is provided a motor pump in which a handling liquid flows inside a cylindrical motor stator, the motor pump being disposed inside the motor stator.
A motor pump characterized in that a rotary flow path is provided inside a substantially cylindrical motor rotor having a permanent magnet and penetrates in the axial direction and has a function of increasing the pressure of a handling liquid with the rotation of the motor rotor. is there.

[0006] Thus, the rotary flow path provided inside the motor rotor can function as an impeller, and the pressure of the liquid to be handled can be effectively increased in the rotary flow path, thereby simplifying the structure. In addition, it is possible to realize a centrifugal (non-volume displacement) pump suitable for use in a region of an extremely small amount of water, which is reduced in size and size.

According to a second aspect of the present invention, the permanent magnet is integrally embedded in the motor rotor by resin molding, and the rotary flow path is provided on the axial center side of the permanent magnet. The motor pump according to claim 1, wherein: Accordingly, the distance in the radial direction between the permanent magnet provided on the motor rotor and the inner peripheral surface of the motor stator is minimized, and the torque can be easily transmitted, so that the whole can be made more compact.

According to a third aspect of the present invention, there is provided the motor pump according to the second aspect, wherein a radial bearing portion is provided on an outer peripheral portion of the motor rotor. Thus, by providing the motor rotor with a function as the main shaft in addition to the function as the impeller, the structure can be simplified and the size and size can be reduced.

The invention according to claim 4 is the motor pump according to any one of claims 1 to 3, wherein the motor stator is integrally provided in a pump casing by resin molding. Thereby, by integrally molding the inner and outer periphery of the motor stator with resin, while preventing the infiltration of the handling liquid into the motor stator winding, the handling liquid is securely included in the pump casing, and Due to the heat insulating property of the resin, it is possible to prevent condensation from forming on the outer peripheral portion and the like of the motor stator. The number of parts can be reduced by integrally providing the suction nozzle or the discharge nozzle of the pump with the pump casing.

According to a fifth aspect of the present invention, in a motor pump in which a handling liquid flows inside a cylindrical motor stator, a pump casing accommodating the motor stator and a nozzle casing having a suction nozzle or a discharge nozzle are provided. A motor pump characterized in that a handling liquid is included in a casing by screw connection.

[0011] Accordingly, the pump casing and the nozzle casing having the inline structure or the nozzle casing having a point symmetrical shape with respect to the axis (there is no problem in function even if the screwing angle is slightly different) are formed by using bolts. And can be combined more easily.

According to a sixth aspect of the present invention, in a motor pump configured so that a handling liquid is filled inside a cylindrical motor stator, an inner peripheral surface of the motor stator is integrally covered with a mold resin. It is a motor pump characterized by the above-mentioned.

Thus, a so-called sealless structure is formed without using a can or the like provided in a conventional general canned motor pump using a resin mold motor, thereby reducing the number of parts and simplifying the structure. Can be achieved. By molding the outer peripheral portion of the motor stator at the same time, dew condensation can be prevented from occurring on the outer peripheral portion of the motor stator due to the heat insulating property of the resin.

[0014]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a motor pump according to a first embodiment of the present invention. This motor pump has a cylindrical motor stator 10, which is integrally embedded in a pump casing 12 by, for example, molding a polyester resin. A discharge nozzle 14 is provided at one axial end of the pump casing 12.
Are integrally connected and reinforced by a rib 16, and an external thread 18 is provided on the outer peripheral portion at the other end.

As described above, by integrally molding the inner and outer circumferences of the motor stator 10 with the resin, it is possible to prevent the infiltration of the handled liquid into the motor stator windings and to ensure that the handled liquid enters the pump casing 12. And dew condensation on the outer peripheral portion of the motor stator 10 and the like can be prevented due to the heat insulating property of the resin. In addition, by providing the discharge nozzle 14 integrally with the pump casing 12, the number of components can be reduced. Furthermore, a so-called sealless structure can be formed without using a can or the like provided in a conventional general canned motor pump using a resin mold motor, thereby reducing the number of parts and simplifying the structure. it can.

The resin mold of the motor stator 10 is
For example, it is first applied to the inner peripheral portion with the outer peripheral portion of a silicon steel plate or the like positioned in the mold, and then applied to the outer peripheral portion with the molded inner peripheral portion positioned in the mold. It should be noted that the pump casing 12 may be used, for example, in applications where the pushing pressure is low.
If the strength of the motor stator is not necessary,
May be applied by omitting the molding of the outer peripheral portion.

A resin nozzle casing 22 integrally connected to the suction nozzle 20 is connected to the open end side of the pump casing 12 by screw connection. That is, the female screw 24 provided on the inner peripheral surface of the large-diameter portion of the nozzle casing 22 is screwed into the male screw 18 provided on the pump casing 12 so that the pump casing 12
Are screwed together, and the casing 12 and 22 contain the liquid to be handled. This nozzle casing 22
Is made of polyester, for example, and the suction nozzle 20 is reinforced by a rib 26. Also, the pump casing 12
A rubber gasket 28 is interposed between the end surface of the nozzle casing 22 and the inner surface of the nozzle casing 22.

A substantially cylindrical motor rotor 30 is disposed inside the pump casing 12.
A rotation flow path 32 penetrating in the axial direction of the motor rotor 30 is provided inside the motor rotor 30. The rotary flow path 32 is formed of a single hollow hole having an inner diameter of about 6 to 8 mm extending along the axis, for example, at the flow path inlet 32 a on the suction nozzle 20 side. The road exit portion 32b is composed of two hollow holes having an inner diameter of 3 to 4 mm that gradually expand outward along the flow direction of the fluid. This has the effect of increasing the pressure of the handling liquid as the motor rotor 30 rotates. Motor rotor 30
Is made of, for example, a polyester resin.

As described above, the rotating flow path 32 provided inside the motor rotor 30 functions as an impeller, and the liquid to be handled is effectively increased in the rotating flow path 32. A centrifugal pump that has a simple structure and is suitable for use in a region with an extremely small amount of water, which is small and compact, can be realized.

The motor stator 10 of the motor rotor 30
A ring-shaped permanent magnet 34, which is located on the outer periphery facing and is rotated by a magnetic field generated by the motor stator 10, is integrally embedded in the motor rotor 30 by molding. Thus, the radial distance between the permanent magnet 34 provided on the motor rotor 30 and the inner peripheral surface of the motor stator 10 is minimized, so that torque can be easily transmitted and the whole can be made more compact. It has become.

A ceramic rotary bearing 36 and a stainless steel thrust collar 38 are provided on the outer periphery of the flow path inlet 32a of the motor rotor 30 by a snap ring 40 via a rotation preventing mechanism (not shown). Fixed.
On the other hand, a fixed bearing 42 made of ceramic is fixedly pressed into the pump casing 12 at a position facing the rotating bearing 36. Thereby, the motor rotor 30 is connected to the pump casing 12 via the bearings 36 and 42.
It is supported rotatably.

As described above, by providing the motor rotor 30 with the function of the main shaft in addition to the function of the impeller, the structure can be simplified and the size and size can be reduced. This motor is a DC brushless motor, is supplied with current from a power supply lead wire 44, and is used at a rotational speed of, for example, about 12,000 revolutions per minute.

According to the motor pump of this embodiment,
When current is supplied from the power supply lead wire 44, the motor rotor 30 rotates, and the handling liquid is sucked into the inside from the suction nozzle 20. The suctioned liquid is supplied to the nozzle casing 2
The current is rectified by the ribs 26 provided on the motor 2, is guided to the rotation flow path 32 of the motor rotor 30, flows along the rotation flow path 32, and is boosted. Then, the handling liquid discharged from the two flow paths of the flow path outlet 32b of the rotary flow path 32 is rectified by the rib 16 in front of the discharge nozzle 14, and is discharged from the pump.

FIG. 2 shows a motor pump according to a second embodiment of the present invention, in which a radial bearing is directly constituted by the outer peripheral surface of the motor rotor 30 and the inner peripheral surface of the pump casing 12. . In other words, in this example,
Coating layer 4 of ceramic or Teflon (registered trademark) resin coating on outer peripheral surface of motor rotor 30
6, a coating layer 48 made of ceramic or Teflon resin coating is formed on the inner peripheral surface of the pump casing 12 at a position facing the coating layer 46, respectively, and a radial bearing is formed by the two coating layers 46, 48. is there.

Further, in this example, the nozzle casing 22
A pump having a shaft portion 50 to be inserted into the hollow portion of the pump casing 12 is used, a female screw 52 is provided on the inner peripheral surface of the pump casing 12 on the nozzle casing 22 side, and A male screw 54 to be screwed with the female screw 52 is provided, and both casings 1
2, 22 are screwed together. Then, coating layers 56 and 5 made of ceramic or Teflon resin coating are formed on the stepped portion facing the insertion end face of the nozzle casing 22 and the end face of the motor rotor 30 of the pump casing 12.
8 with the coating layers 56, 58 of the motor rotor 30.
The coating layers 60 and 62 made of ceramic or Teflon resin are respectively formed at positions facing the surfaces, and the coating layers 56, 58, 60 and 62 constitute an axial bearing.

In this pump, most of the axial load is transferred between the permanent magnet 34 of the motor rotor 30 and the motor stator 10.
The axial bearing is composed of the coating layers 56, 58, 60, and 62, as described above, and can be reinforced.

According to this example, the actual bearing member can be omitted to simplify the structure, and the pump can be made extremely small and compact. In this example, an example is shown in which a coating layer is formed by applying a ceramic or Teflon resin coating to the axial and radial bearing portions. It is also possible to use a tube or plate made of stainless steel or to constitute a magnetic bearing.

[0028]

As described above, according to the present invention,
It is possible to provide a centrifugal (non-displacement type) pump which is suitable for use in an area with a very small amount of water and a small output, has excellent durability, has a simple structure, is small and compact, and has good productivity.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a motor pump according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a motor pump according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Motor stator 12 Pump casing 14 Discharge nozzle 18, 54 Male screw 20 Suction nozzle 22 Nozzle casing 24, 52 Female screw 30 Motor rotator 32 Rotating flow path 32a Flow path entrance part 32b Flow path exit part 34 Permanent magnet 36 Rotation side bearing 42 Fixed-side bearing 44 Power supply lead wire 46, 48, 56, 58, 60, 62 Coating layer 50 Shaft

Claims (6)

[Claims] 1. A motor pump in which a handling liquid flows inside a cylindrical motor stator, wherein said motor pump is disposed inside said motor stator, and has a substantially cylindrical motor rotor having permanent magnets therein. A motor pump having a rotary flow path that penetrates and has a function of increasing the pressure of a handling liquid as the motor rotor rotates. 2. The motor according to claim 1, wherein the permanent magnet is integrally buried in the motor rotor by resin molding, and the rotary flow path is provided closer to the axis than the permanent magnet. Motor pump. 3. The motor pump according to claim 2, wherein a radial bearing portion is provided on an outer peripheral portion of the motor rotor. 4. The motor pump according to claim 1, wherein said motor stator is integrally provided in a pump casing by resin molding. 5. A motor pump in which a handling liquid flows inside a cylindrical motor stator, wherein a pump casing accommodating the motor stator and a nozzle casing having a suction nozzle or a discharge nozzle are screw-connected to each other to form a casing. A motor pump characterized in that a handling liquid is contained therein. 6. A motor pump in which a handling liquid is filled inside a cylindrical motor stator, wherein an inner peripheral surface of the motor stator is integrally covered with a mold resin. .