JPH0521197U - Canned motor pump - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide an efficient canned motor pump having a small air gap length, which can prevent deformation and destruction even if the partition plate between the stator and the rotor is thin. To do. [Structure] A stator is fixed to a casing, and a rotor is disposed so as to face the stator. The rotor is composed of a magnet, and is orthogonal to the magnetic field direction of the rotor magnet 1 and orthogonal to the rotation axis of the rotor. The rotor magnet 1 is embedded in or directly connected to the impeller 3 in the pump casing 8 to isolate the atmosphere in the pump casing 8 from the stator. For this reason, the gap between the facing surfaces of the rotor and the stator is a canned motor pump constituted by the partition plate 5, and the stator has an iron core type.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a canned motor pump, and more particularly to a canned motor pump having no sealing mechanism.

[0002]

[Prior Art]

 Conventionally, this type of canned motor has a structure in which an axial gap type DC motor without an iron core is used for a stator coil. An example of using the above DC motor will be described with reference to FIG. 3. An impeller 3 is rotatably supported in a pump casing 8 by a bearing 4 (consisting of a fixed side bearing 4a and a rotating side bearing 4b). ing . A rotor magnet 1 magnetized so as to form a magnetic field in an axial direction is embedded in the impeller 3. A motor casing 11 is connected to the pump casing 8, and a partition plate 5 is arranged to isolate the interior of the pump casing from the interior of the motor casing. Further, only a plurality of stator coils 2 are arranged so as to face the rotor magnet 1 with the partition plate 5 sandwiched therebetween, and the central portion 6 of the stator coil is a space. With the above structure, a canned motor pump which is advantageous in terms of thinness and compactness was constructed.

[0003]

[Problems to be solved by the device]

However, the actual partition plate 5 is made as thin as possible for the reason of reducing the can loss as much as possible and the air gap t ₁ for improving the characteristics of the magnetic circuit. In such a case, the partition plate is deformed or broken in an extreme case due to the pressure inside the pump casing 8. Further, as shown in FIG. 3, the air gap t ₁ means that the coil thickness also exists as an air gap, and since the magnetic resistance against the magnetomotive force of the coil is large, the magnetic flux density acting on the rotor magnet 1 becomes low. Therefore, since the magnetic flux density at the operating point of the stator coil that contributes to the generation of motor torque is low and the rotational force is not effectively generated, the stator and rotor that are considerably large in order to give the required rotational force to the pump output. Inevitably. For the above reasons, the idea was a canned motor pump that had no practical value and was not implemented yet.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent the above problems from being deformed or destroyed even if the partition plate between the stator and the rotor is thinned. Another object is to provide a highly efficient canned motor pump that has a small air gap length.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a canned motor pump of the present invention has a stator fixed to a casing and a rotor arranged so as to face the stator, and the rotor is constituted by a magnet. A direct current motor having a plurality of stator coils arranged so as to be orthogonal to the direction of the magnetic field of the magnet and orthogonal to the rotation axis of the rotor, wherein the rotor magnet is embedded or directly connected to an impeller in a pump casing, In a canned motor pump in which the air gap between the rotor and the stator in order to isolate the atmosphere in the pump casing from the stator is a partition plate, the stator is made of an iron core. It features a canned motor pump.

[0006]

[Action]

 By configuring the canned motor pump as described above, since the partition plate can be reinforced and supported by the upper end of the iron core, the partition plate will not be deformed or destroyed by the internal pressure of the pump casing.Thus, make the partition plate as thin as possible. The air gap length between the rotor magnet and the stator coil can be made as small as possible. Also, by using a soft magnetic material iron core or a solidified iron-based magnetic powder iron core as the iron core, the air gap of the motor becomes substantially between the upper end of the iron core and the rotor magnet, so the magnetic flux density at the operating point of the stator coil is increased. It becomes possible to construct an excellent magnetic circuit. Moreover, due to the excellent magnetic characteristics of the iron core, iron loss such as eddy current loss in the iron core due to the rotating magnetic field generated by the rotation of the rotor magnet and the alternating current to the stator coil can be minimized.

[0007]

【Example】

 An embodiment of a canned motor pump according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a canned motor pump according to the present invention. An impeller 3 is rotatably supported in a pump casing 8 by a bearing 4 (consisting of a stationary bearing 4a and a rotating bearing 4b). A rotor magnet 1 made of a permanent magnet magnetized so as to form a magnetic field in the axial direction is embedded in the impeller 3. The stator coil 2 mounted on the iron core 7 is separated from the inside of the pump casing 8 by the partition plate 5, and is disposed so as to face the rotor magnet 1. An example of mounting the stator coil 2 on the iron core 7 is shown in FIG. As is apparent from FIG. 1, the partition plate 5 has a structure in which it is in close contact with the upper end of the iron core 7.

The pump casing 8 has a pump suction port 9 and a pump discharge port 10, and is connected to a motor casing 11.

Next, the operation of the canned motor configured as described above will be described.

Now, assuming that the stator coil 2 is energized and the rotor magnet 1 is rotated, a pressure that maximizes the shutoff operation is applied inside the pump casing 8. At this time, the same pressure is applied to the partition plate 5, but since the iron core 7 supports the partition plate 5 at the upper end portion and functions as a reinforcing material, this pressure prevents the partition plate 5 from being deformed or destroyed. This can be prevented, the thickness of the partition plate 5 can be made as thin as possible, and the magnetic characteristics can be improved.

Further, the air gap t ₁ is between the end surface of the iron core 7 and the end surface of the rotor magnet 1 as shown in FIG. 1, and the air gap length is short and magnetic characteristics are excellent. Further, during the pump operation, an eddy current flows through the iron core 7 in the radial direction as a main path due to the rotating magnetic field from the rotor magnet 1 and the alternating current of the stator coil 2 accompanying it. In order to minimize this eddy current and obtain a high magnetic flux density, a method of stacking silicon steel plates in the radial direction to form an iron core is considered, but the slot pitch for mounting the coil must be adjusted in the radial direction. Therefore, a soft magnetic core or a powdered solid core of iron-based magnetic powder, which is commonly called a ferrite core, is used to avoid such an iron core that is difficult to manufacture. This facilitates the manufacture of the iron core, and the soft magnetic iron core has excellent magnetic characteristics with respect to high frequencies and can minimize iron loss. The iron-based magnetic powder solidified iron core is an iron-based magnetic powder powder coated with an insulating resin material and subjected to special processing as a binder and press-molded, so the resin as a binder prevents the flow of eddy currents. However, the eddy current loss is suppressed as much as possible, the magnetic body forms a magnetic path, and a large magnetic flux density can be obtained, so that an efficient canned motor can be achieved. Therefore, by constructing the canned motor as in this embodiment, it is possible to put it into practical use, and it becomes possible to provide an axial air gap type canned motor pump that is much more excellent in efficiency than conventional models.

[0013]

[Effect of the device]

 As described above, according to the present invention, since the partition plate can be prevented from being deformed or destroyed by the internal pressure of the pump casing by pressing the partition plate at the upper end of the iron core, the partition plate should be made as thin as possible. It will be possible. Moreover, the air gap length between the rotor magnet and the stator coil can be made as small as possible.

Further, according to the present invention, since the field from the rotor magnet can be configured as an efficient magnetic path, the magnetic flux density can be increased, an excellent magnetic circuit can be configured, and the eddy current loss Since the iron loss can be minimized, the output suitable for the pump load can be obtained with high efficiency.

[Brief description of drawings]

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

2A and 2B are explanatory views showing a state in which a coil is attached to an iron core in a canned motor pump according to the present invention, FIG. 2A is a front view, and FIG. 2B is a side view.

FIG. 3 is a sectional view showing a conventional canned motor pump.

[Explanation of symbols]

1 Rotor Magnet 2 Stator Coil 3 Impeller 4 Bearing 4a Fixed Side Bearing 4b Rotating Side Bearing 5 Partition Plate 6 Stator Coil Central Part (Space) 7 Iron Core 8 Pump Casing 9 Pump Suction Port 10 Pump Discharge Port 11 Motor Casing t ₁ Air Gap

Claims (3)

[Scope of utility model registration request] 1. A stator having a stator fixed to a casing, and a rotor disposed so as to face the stator. The rotor is constituted by a magnet, and is orthogonal to the direction of the magnetic field of the rotor magnet. A DC motor having a plurality of stator coils arranged so as to be orthogonal to the rotation axis is also provided, and the rotor magnet is embedded in or directly connected to an impeller in a pump casing to isolate an atmosphere in the pump casing from the stator. Therefore, in the canned motor pump in which the gap between the facing surfaces of the rotor and the stator is constituted by a partition plate, the stator has an iron core type. 2. A canned motor pump according to claim 1, wherein an upper end portion of an iron core of the stator is brought into close contact with the partition plate to reinforce and support the partition plate. 3. The canned motor pump according to claim 2, wherein a soft magnetic material of a ferrite core or an iron-based magnetic powder solidified iron core material is used for the iron core of the stator.