JPH0784875B2 - Magnet pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnet pump in which an impeller having a magnet fixed thereto is magnetically rotated from the outside through a separator, and particularly, the rotation of the impeller This is a magnet pump in which the impeller is directly rotated by the magnetic force of a stator arranged along a plane perpendicular to the axis.

[Conventional technology]

A conventional magnet pump will be described with reference to FIG. 5 which is a longitudinal sectional view. In the figure, a drive side magnet 4 having permanent magnets of different polarities alternately arranged is fixed on the circumference of an end surface of a disk 3 of a magnetic insulating material fixed to the end of a motor shaft 2 of a motor 1. The lower bracket 5 and the pump casing 6 of the motor 1 are hermetically sealed via a separator 7 made of a non-magnetic material and fixed by a bolt nut 8.

The pump casing 6 has a suction port 9 of the pump casing 6.
A boss 11 is provided at the center of a radial arm 10 integrally formed with the arm 10, and a space between the arms 10 serves as a suction passage. The boss
A pump shaft 12 concentric with the motor shaft 2 is fixed to 11, and a bearing metal 14 with a flange press-fitted into an impeller 13 is slidably fitted on the pump shaft 12. Reference numeral 15 is a liner ring that is press-fitted into the pump casing 6 and fits with the outer periphery of the suction portion of the impeller with a small gap to seal water.

At the end of the impeller 13 on the motor side, an impeller-side magnet 16 is embedded and fixed so as to be opposite to the driving-side magnet 4 via a separator 7 and in which permanent magnets having different polarities are alternately arranged. A strainer 19 is fitted into the leg 17 of the pump casing 6, and is held so as to cover the outer circumference of the pump casing 6 by a base plate 18 which is attracted to the pump casing 6 by a bolt (not shown).

When the motor 1 is energized, the motor shaft 2, the disk 3, and the driving magnet 4 rotate, the impeller-side magnet 16 is driven by the magnetic force of the driving-side magnet 4, and the impeller 13 is the pump shaft. The liquid rotates on 12 and passes through the stratator 19 and the suction port 9 into the pump casing 6, is sucked by the impeller 13 to be pressurized, and is discharged from the discharge port 21. Some of the liquid is from the high pressure side to the impeller side magnet.
It passes between 16 and the separator 7 and circulates from the balance hole 22 toward the center toward the low pressure side to balance the pump thrust. With this configuration, the motor shaft 2 and the pump shaft 12 are separated from each other, so that a shaft seal device is not required, and the handling is isolated by the separator 7 between the motor and the pump. ing. Therefore, when transferring a liquid such as a strongly acidic liquid, a strongly alkaline liquid, or a highly toxic liquid that should not be leaked to the outside, on the contrary, the manufacturing process of food, medicine, soft drink, etc., This kind of pump is used in cases such as semiconductor manufacturing processes where it is necessary to prevent external contaminants from mixing into a clean handling liquid.

FIG. 6 is a sectional view of a magnet pump in which a magnetic gear is formed in the axial direction similarly to the type of the magnet pump of the present invention (JP-A-49-129106).

In the figure, an impeller housed in a pump casing 6
An annular permanent magnet 16 is fixed to the back surface of 13 along a plane perpendicular to the pump shaft 12 of the impeller 13. One side of the pump casing 6 is closed by a back plate 20.
20 is provided with a stator coil 23 and a bearing 24. The impeller 13 is supported by a bearing 25 provided on the side of the pump casing 6 and the bearing 24, but is attracted to the back plate 20 side by the suction force of the stator coil 23, so that the back plate is provided.
The axial end surface 26 of the bearing 24 provided on the 20 on the side of the impeller 13 also serves as a thrust bearing. The impeller 13 of FIG. 6 is an open type and is suitable for handling a fluid containing slurry and foreign matter. Since the stator coil 23 is energized in the state of being immersed in the liquid (the power supply line is not shown), the entire plastic film 27 is used to maintain the insulation performance.
It is covered with.

The stator coil 23 is wound in three phases in order to give a rotating field. And the impeller side magnet 16 is
Correspondingly, different magnetic poles are arranged along the ring so as to alternately face the stator coil 23. Here, when the stator coil 23 is powered on, a rotating field is formed, and the impeller 13 rotates at the number of rotations thereof, so that fluid flows out from a discharge port (not shown).

[Problems to be solved by the invention]

Not only the magnet pump having the magnetic gears in the axial direction as described above, but the magnet pumps having the permanent magnets fixed to the impeller side have few high output as compared with general pumps. That is, since a general pump can directly drive the impeller by the output shaft of a prime mover such as a motor or an engine, the strong electromagnetic force generated in the motor and the output of the internal combustion engine are permanent even if the power loss in the shaft sealing part is expected. This is because it is easy to obtain a large force compared with the transmitted power of the magnet coupling by the magnet. In particular, in the case of a magnet pump in which a permanent magnet is embedded directly on the back surface of the impeller as described above to form an axial magnetic gear, the size of the impeller-side magnet is neglected. Since it cannot be increased unnecessarily, it is disadvantageous for a pump for transferring liquid.

Further, the magnet pump shown in FIG. 6 is effective as a small pump because of its simplified structure, but the stator coil 23, the impeller-side magnet 16, the impeller 1
3, and the mass balance, hydraulic balance and magnetic balance of the pump casing 6 must all be perfectly balanced, which is a manufacturing problem. Furthermore, in the conventional magnet pump having a magnetic gear in the axial direction, the power loss of the thrust bearing is large, and there are various problems such as the need to increase the starting torque, and the ratio is not so large.

Therefore, the magnet pump of the present invention is a magnet pump of the type in which a magnetic gear is formed in the axial direction, reduces the starting torque, supports the thrust load during operation with a slight power loss, and rotates. The purpose of the invention is to reduce eddy current heat generation loss due to a magnetic field, to effectively dissipate heat generated by the stator coil without providing a special cooling means, and to have a simple component structure. is there.

[Means for solving problems]

The present invention relates to a pump casing, an impeller housed in the pump casing, and having a permanent magnet embedded in an annular shape along a plane perpendicular to the axis on the back side, and the permanent magnet fixed to the pump casing. In a magnet pump including a stator coil driven via a separator, the impeller-side permanent magnet is embedded in a blade portion of the impeller, and a stator coil is laminated to form a sheet coil group. The end face of the stator coil on the impeller side is covered with a separator made of α-SiC ceramics containing silicon carbide as a main component and a small amount of beryllium or a beryllium compound to form the fixed side sliding face. A ceramic flat plate is fixed to a part or all of the back surface of the impeller facing the separator plate to form a rotary side sliding surface, and one of the fixed side sliding surface and the rotary side sliding surface is formed. Move to face A mug the net pump having grooves for generating.

[Work]

In the magnet pump of the present invention, since the separator made of SiC ceramics with beryllium added is provided on the end face of the stator coil facing the permanent magnet on the impeller side,
The magnetic permeability of the magnetic field lines generated by the stator coil is excellent,
Little heat is generated by this separator.

Further, since the stator coil is formed by the laminated sheet coil group, its surface is also substantially flat,
The separator is easily bonded, and the heat generated in the stator coil is easily dissipated. And
Since the liquid contact surface of the separator, which can be referred to as the heat radiating portion of the stator coil, faces the back surface of the impeller, the liquid is suitably stirred by the rotation of the impeller.

Further, since the impeller-side magnet is embedded in the blade portion of the impeller, a large magnet can be used without increasing the weight of the entire impeller. In this way, the ratio of magnets to the entire impeller can be increased, so that the impeller having the same blade shape can reduce the load on the magnet per unit weight as compared with the conventional impeller. Also,
Since the center of gravity of the impeller-side magnet approaches the flow path formed in the front surface of the impeller, twisting with respect to the blade is reduced.

〔Example〕

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

FIG. 1 is a vertical sectional view showing an embodiment of the present invention. In the figure, an impeller 13 is housed in the pump casing 6, and a permanent magnet 28 is embedded in the back surface of the impeller 13 in an annular shape along a plane perpendicular to the rotation axis of the impeller 13. The permanent magnets 28 are evenly divided into a plurality of pieces at equal intervals in the circumferential direction, and the embedded positions thereof correspond to the positions of the blades 29 of the impeller 13. 30 is a fluid flow path,
Although the permanent magnet 28 is in a positional relationship that intersects with the permanent magnet 28 in the axial direction of the impeller 13, the permanent magnet 28 is embedded in the blades 29 and therefore is not exposed in the flow path 30 of the impeller 13.

The center of the back surface of the impeller 13 serves as a bearing,
A ceramic flat plate 31 made of a silicon carbide sintered body is fixed to the center of the plate 13, and the surface of the flat plate 31 serves as a rotation-side sliding surface.

After this sliding surface on the rotation side is finished smooth (Rmax3
The spiral groove having a depth of about 3 to 50 μm is formed.

On the other hand, at a position axially opposed to the ceramics flat plate 31 forming the rotating side sliding surface, a separator plate composed of the ceramics flat plate 32 forming the stationary side sliding surface is provided in the stator coil.
It covers the surface of 23. Beryllium or beryllium compound (especially Be
O is good), silicon carbide ceramics containing
This ceramic has high electrical resistance (10 ^{10 Ω} / cm
Above), and because it is a ceramics material with good heat conduction and high mechanical strength, it has the advantages that there is little loss due to eddy currents and that the heat radiation of the stator coil is great.

Since the central portion of the stator coil 23 has no coil and is hollow, it is reinforced by the resin 34. Stator coil 23
Is a sheet coil formed by stacking a plurality of sheet coils in the axial direction and connecting the layers, and the layers are adhered by an adhesive. And flat plate 32
And the stator coil 23 are also bonded. This flat plate 32
An outer peripheral side of the pump casing 6 is in contact with the pump casing 6, and an o-ring 33 is interposed between the pump casing 6 and the liquid so that the liquid inside the pump casing 6 does not flow out. The stator coil 23 is fixed to the cover 35 by a known means (not shown), and the cover 35 is fixed to the casing 6 by bolts / nuts (not shown). 36 is a lead wire for supplying power to the stator coil 23, the uppermost portion of the stator coil 23,
That is, the sheet coil 37 located on the side of the separator 32 has the impeller 13
A sheet coil incorporating a magnetic detecting element for detecting the position of the magnet 28 fixed to the stator 28 is connected to a control unit (not shown) so that the stator coil 23 generates excitation in an optimum state. There is.

FIG. 2 is a front view of the rotation side sliding surface of FIG. In the figure, a plurality of spiral grooves 38 (shown in satin in FIG. 2) are formed on the rotary sliding surface formed on the surface of the ceramic flat plate 31 fixed to the center of the back surface of the impeller 13. ) Has been formed. The groove 38 is deeper than the adjacent land 39 by about 3 to 50 .mu.m, and the central portion serves as a pressure equalizing portion 40 so that the inner peripheral edge of the groove 38 directly communicates with all the grooves 38. The rotation-side sliding surface is formed by smoothing the surface of the ceramic flat plate 31 by lapping to cover the portion corresponding to the land 39 with a plastic or metal,
The spiral groove 38 is processed by a shot blast, and the spiral groove 38 may have any known spiral pattern. Reference numeral 41 represents the rotation direction of the impeller 13, and the rotation of the impeller 13 draws the liquid between the rotating-side sliding surface and the opposed fixed-side sliding surface, and the liquid is substantially fluidized between them. Supported by the membrane, the impellers 13 will rotate without making direct contact with each other.

FIG. 3 is a front view of the impeller 13 of FIG. 1 as seen from the suction side. The impeller 13 is of a type commonly referred to as a closed impeller. Channel
27 are provided. The blade 29 is wider toward the outer peripheral side, and a permanent magnet 28 having a shape similar to the blade 29 is embedded in the blade 29 in order to increase the rotation torque. Reference numeral 42 is a line indicating the position of the cross section used when displaying the impeller 13 of FIG. 1 on the drawing.

FIG. 4 is a vertical sectional view showing another embodiment of the present invention.

In this embodiment, the stator coil for driving the impeller 13 is common to that of the embodiment shown in FIG. 1, but the structure of the impeller 13 is different.

That is, on the back surface of the impeller 13, the entire permanent magnet 28 embedded in the impeller 13 is covered with a single ceramic flat plate 42, and a spiral groove for generating dynamic pressure is formed on the surface of the flat plate 42. The sliding portion receives a thrust load, and wear resistance is given to the entire back surface of the impeller 13.
Further, even on the front surface of the impeller 13, a sliding portion 43 in which a groove for dynamic pressure generation is formed on one end surface is provided, and even if the axial position of the impeller 13 changes, either the front surface or the back surface is formed. It is supported on the side by dynamic pressure. That is,
A boss 44 formed integrally with the casing 6 in the suction port 9
A ceramic bearing plate 46 is fixed to the end surface of the bearing via an elastic body 45, and a spiral dynamic pressure generating groove shown in FIG. 2 is formed on the end surface of the bearing plate 46 on the impeller 13 side. Impeller
It is arranged so as to face a smoothed end surface 47 in the central portion of the front surface of 13. Therefore, even if the valve (not shown) on the discharge port 21 side is closed and the pressure in the casing 6 rises and the impeller 13 is pressed toward the suction port 9 side by the application of the pressure, the bearing plate 46 and A fluid lubricating film is formed between the end surface 47 of the impeller 13 and the impeller 13 can rotate with a small sliding resistance. Further, even when the impeller 13 is pressed on either side, since the sliding portion is formed by the two surfaces parallel to each other, the damping effect always causes the impeller 13 to move. The runout is controlled.

In both the embodiments shown in FIGS. 1 and 4 described above, the entire end face of the stator coil 23 facing the casing 6 is a single 1w.
Although it was covered with a separator consisting of a flat plate 32 of α-silicon carbide ceramic containing less than t% beryllium oxide, in order to reduce the loss due to the eddy current, only the part where the coil is formed has this α- It suffices to cover it with the silicon carbide ceramic separator 32. For example, it is possible to form the sliding portion by another ceramic in the central space of the annular thin separator.

〔The invention's effect〕

The magnet pump of the present invention includes a pump casing, an impeller housed in the pump casing, and an annular permanent magnet embedded in a back surface of the pump casing along a plane perpendicular to the axis, and a fixed member for driving the permanent magnet. Since the magnet pump is provided with a child coil, the number of elements constituting the magnet pump is extremely small, which results in a very simplified pump, and the stator coil is laminated. Since it is formed of a sheet coil group, manufacturing and assembling are easy, and beryllium or a beryllium compound (especially BeO is preferable) on the end face of the stator coil on the impeller side, which has good thermal conductivity and large electric resistance. ) Is included in the separator, so that the heat generated in the stator coil faces the rear surface of the rotating impeller. The liquid contact surface effectively dissipates into the fluid in the casing, and at the same time there is no loss of magnetic force due to the separator plate, and the sliding surface is formed between the flat surfaces of the ceramics that are smooth, and dynamic pressure is generated on one of the flat surfaces. Since the groove is formed, the sliding resistance due to the rotation of the impeller is extremely small, and the two sliding surfaces are made of ceramics, which are hard materials, so that they have excellent wear resistance. , There are various advantages.

Therefore, according to the magnet pump of the present invention, the sliding resistance is small and the loss due to the eddy current is small, so that not only an efficient magnet pump can be obtained, but also wear resistance,
Since it has excellent corrosion resistance and has a damping effect, a stable pump can be obtained in all aspects, and its productivity is also good, which is an effect that cannot be expected with conventional magnet pumps.

Further, by embedding the magnet on the impeller side in the blade portion of the impeller, the weight of the entire impeller is reduced and the moment of inertia is reduced. Therefore, there is an advantage that the movement of the rotating magnetic field due to the stator coil can be easily followed and slipping does not easily occur. Further, since the impeller-side magnet embedded in the impeller blade portion can be enlarged to a position where it intersects with the impeller flow path in the rotational axis direction of the impeller, a large torque can be obtained without widening the impeller width. Obtainable.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a schematic view of a groove for generating dynamic pressure formed in a sliding portion of FIG. 1, and FIG. 3 is a blade of FIG. FIG. 4 is a front view of a vehicle, FIG. 4 is a vertical cross-sectional view showing another embodiment of the present invention, and FIGS. 5 and 6 are vertical cross-sectional views of different conventional magnet pumps. 6 …… Pump casing, 13 …… Impeller, 23 …… Stator coil, 28 …… Permanent magnet, 29 …… Wing, 27, 30 …… Flow path, 31, 42…
… Ceramic plate, 32 …… Plate (separator), 38 ……
Groove, 39 ... Land, 40 ... Pressure equalizing section, 44 ... Boss, 45 ... Elastic body, 46 ... Bearing plate, 47 ... End surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Chiba 4720 Fujisawa, Fujisawa City, Kanagawa Prefecture, Ebara Research Institute Co., Ltd. (56) References JP-A-49-47907 (JP, A) JP-A-60-26814 (JP, A)

Claims (1)

[Claims] 1. A pump casing, an impeller that is housed in the pump casing, and has a permanent magnet embedded in an annular shape on a rear surface side thereof along a plane perpendicular to the axis, and the permanent magnet is fixed to the pump casing. In a magnet pump including a stator coil driven via a separator plate, the impeller-side permanent magnet is embedded in a blade portion of the impeller,
The stator coil is formed by a laminated sheet coil group, the impeller side end surface of the stator coil is composed mainly of silicon carbide, and a small amount of beryllium or a beryllium compound coexists with α-silicon carbide. A fixed side sliding surface is covered with a separator made of ceramics, and a ceramic flat plate is fixed to a part or all of the back surface of the impeller facing the separating plate to form a rotating side sliding surface. A magnet pump, characterized in that a groove for generating a dynamic pressure is formed on either one of the sliding surface and the rotation-side sliding surface.