JPH0350503B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a partition wall for a magnetic coupling, which drastically reduces eddy current loss generated by a rotating magnetic field while maintaining thermal and mechanical strength. , relates to a partition body that significantly improves the transmission efficiency of a magnetic coupling.

[Background technology of the invention and its problems]

A magnetic coupling is a non-contact joint that transmits power by rotating a driving magnet and applying the rotating magnetic field to the driven rotor through a partition, thereby generating rotational torque in the rotor. Since the driving side and the driven side are fluidly isolated by the partition, it is used for power transmission of fluid machines such as pumps, blowers, and compressors that handle fluids where leakage is averse.

By the way, it is desirable that the partition of the magnetic coupling satisfy the following five conditions.

(a) Since it is placed in a rotating magnetic field with high magnetic flux density,
It must be a non-magnetic material, not a magnetic material that causes magnetic short-circuiting or magnetic shielding.

(b) Since it is placed in a rotating magnetic field with high magnetic flux density,
It must be a high electrical resistance material with low eddy current loss caused by this rotating magnetic field.

(c) Must have the thermal and mechanical strength to withstand the temperature and pressure of the fluid being handled.

(d) It must have chemical strength (corrosion resistance) that can withstand the corrosion of the fluid to be handled.

(e) It must have a sealing property that prevents the fluid being handled from leaking.

Conventionally, most of the bulkheads of magnetic couplings are made of resin only, and of the above five conditions, (a), (b), (d), and (e) are completely satisfied. The thermal and mechanical strength of the object (c) is inferior.

Therefore, when the fluid being handled is at high temperature or high pressure,
Alternatively, if the strength decreases due to an increase in the diameter of the partition wall due to an increase in the capacity of the magnetic coupling, the partition wall may be constructed of only non-magnetic corrosion-resistant steel plates such as austenitic stainless steel or Inconel steel. Or, if a resin material is required for corrosion resistance, a reinforcing body made of the steel plate and having the same shape as the partition body is attached to the partition body made of the resin material to increase the strength. By using the steel plate, the eddy current loss described in (b) above occurs.

This eddy current loss is caused by the lines of magnetic force of the rotating magnetic field generated by rotating the drive side magnet of the magnetic coupling, which cross the stationary partition at right angles, causing an induced current called an eddy current in the partition. , is the Joule heat loss generated in the partition body by this eddy current.

The value of this eddy current loss (W _E ) is determined when the partition wall is filled with no defects in its constituent materials and has a constant thickness in the magnetic gap where the driving side magnet and driven side rotor face each other. If formed,
It can be calculated using the following formula (1).

W _E = π/8D ³ · L · t · B ² · ω ² · σ (W) ... (1) Here, D (m): Diameter of the cylindrical partition.

L (m): Length of magnetic gap.

t(m): Thickness of partition wall.

B (Wb/m ² ): magnetic flux density of the magnetic gap.

ω (rad/sec): Angular velocity of rotating magnetic field.

σ (Ω ^-1 /m): Specific electrical conductivity of the partition wall.

Therefore, in the above equation (1), the partition wall is made of a high electrical resistance resin material, that is, only a resin material whose intrinsic conductivity σ (Ω ^-1 /m) is generally negligible compared to the non-magnetic corrosion-resistant steel plate. , the eddy current loss W _E
(W) does not substantially occur and is ideal in this respect, but since resin materials are inherently inferior in thermal and mechanical strength, they cannot be used with metal materials such as the above-mentioned steel plate, whose tensile strength changes extremely little with temperature. In comparison, the tensile strength at room temperature is more than an order of magnitude lower, and even for materials with relatively excellent heat resistance, the tensile strength is halved when the temperature rises to around 100°C. When strength is required, the occurrence of eddy current loss is unavoidable, so it is necessary to use a metal material such as the steel plate for the partition wall.

As a result, eddy current loss occurs, which accounts for approximately 10 to 20% of the power transmitted by the magnetic coupling, and the transmission efficiency of the magnetic coupling is extremely reduced. It has the drawback of becoming expensive and increasing operating costs.

[Purpose of the invention]

The present invention has been made in order to improve the above-mentioned drawbacks, and because of its thermal and mechanical strength, the partition wall of a conventional magnetic coupling is used alone or as a reinforcing material for a resin material. A metal material such as a non-magnetic corrosion-resistant steel plate is placed in the magnetic gap where the driving side magnet and the driven side rotor face each other.
Focusing on the fact that excessive eddy current loss was occurring due to the structure having no defects and being filled with a constant thickness, the partition wall was replaced with a cup-shaped sealing part to prevent fluid leakage and a metal A first reinforcing part made of metal material to increase axial strength, and a second reinforcing part made of metal material to increase radial strength, and both the reinforcing parts suppress generation of eddy current. By forming this structure, it has superior thermal and mechanical strength compared to partition walls made only of non-metallic materials such as resin, and drastically reduces eddy current loss compared to partition walls of conventional structure using the above-mentioned metal materials. The present invention provides a partition wall body for a magnetic coupling whose transmission efficiency is greatly improved.

[Summary of the invention]

The partition body of the magnetic coupling of the present invention is
a cup-shaped seal to prevent fluid leakage;
a first reinforcing portion for increasing the thermal and mechanical strength of the sealing portion in the axial direction; and a first reinforcing portion that is in contact with the first reinforcing portion and increasing the thermal and mechanical strength of the sealing portion in the radial direction. and a second reinforcing part for the cup-shaped sealing part, and the first reinforcing part is made of a plurality of rod-shaped reinforcing pieces made of a metal material, which are made substantially parallel to the axial direction and are arranged in an annular shape concentrically around the cylindrical part of the cup-shaped sealing part. and the second reinforcing portion is formed by arranging a cylindrical coil made of a metal material or a plurality of rings made of a metal material sequentially arranged in the axial direction concentrically on the cylindrical portion of the cup-shaped sealing portion. It is something.

[Embodiments of the invention]

Next, an embodiment in which the present invention is applied to a magnetic coupling pump will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a magnetic coupling pump, which is constructed by integrally connecting a centrifugal pump 2, a magnetic coupling 3, and an electric motor 4.

A cup-shaped partition 6 is disposed within the frame 5 of the magnetic coupling 3, and its flange portion 6a is attached to a resin casing 8 disposed along the inner surface of the metal casing 7 of the pump 2. They are brought into contact with each other through a ring 9, and are sandwiched between the frame 5 and the metal casing 7 and fixed in a liquid-tight manner.

The driving side magnet 10 and the driven side magnet 11 of the magnetic coupling 3 are arranged opposite to each other via the cylindrical portion 6b of the partition wall body 6,
The driving side magnet 10 is a magnet mounting member 13 inserted and fixed onto the rotating shaft 12 of the electric motor 4.
A yoke 14 is closely attached to the inner diameter of the driven side magnet 11, and this yoke 14
and the driven side magnet 11 are integrally resin molded to form a driven side rotor 15,
This driven side rotor 15 has the resin casing 8
A resin impeller 16 disposed inside is screwed.

Further, slide bearings 17, 17 are mounted on the inner diameter part of the driven side rotor 15, and these slide bearings 17, 17 are connected to the stationary shaft supported between the bottom 6c of the partition wall 6 and the resin casing 8. 18, and the driven side rotor 15 is rotatably supported.

Next, the structure of the partition wall body 6 will be explained with reference to FIG.

The partition wall body 6, whose cylindrical portion 6b is disposed in the magnetic gap 19 between the driving side magnet 10 and the driven side magnet 11, includes a cup-shaped sealing portion 20 made of a resin material, and a cup-shaped sealing portion 20 made of a resin material. A first reinforcing portion 22 that is adhered to increase thermal and mechanical strength in the axial direction, and this first reinforcing portion 22
A second reinforcing portion 23 is attached to the reinforcing portion 23 to increase thermal and mechanical strength in the radial direction.

In FIG. 3, the first reinforcing portion 22
A plurality of rod-shaped reinforcing pieces 24 made of non-magnetic steel such as austenitic stainless steel and having a rectangular cross section are arranged substantially parallel to each other in the axial direction and adjacent to the outer peripheral surface of the cylindrical part 20b of the sealing part 20 with gaps 25 between them. One end of the plurality of reinforcing pieces 24 is welded to the end plate 26 made of non-magnetic steel adjacent to the bottom 20c of the sealing part 20, and the other end of the plurality of reinforcing pieces 25 is arranged in a concentric ring shape. Flange portion 2 of the sealing portion 20
They are bent outward on the 0a side and locked to a ring 27 made of a resin material so as not to come into contact with each other.

Further, as shown in FIG. 2, the first reinforcing portion 2
The cylindrical coil 28 made of non-magnetic steel is wound around the outer circumferential surface of the cylindrical coil 2 with a gap 29 between each other so that adjacent parts do not come into contact with each other.
8 is welded to the end plate 26, and the other end is locked to the ring 27, thereby forming the second reinforcing portion 23.

A flange reinforcing body 30 made of a metal material is fitted into the flange part 20a of the sealing part 20, and a space surrounded by the reinforcing body 30 and the flange part 20a is filled with a resin curable filler 21. As a result, the ring 27, the plurality of reinforcing pieces 24 locked to the ring 27, and the cylindrical coil 28 are fixed.

According to the embodiment configured in this manner, in the first reinforcing portion 22, the rod-shaped reinforcing pieces 24 are arranged in an annular manner substantially parallel to the axial direction, and both ends thereof are connected to the flange portion 6a of the partition wall 6. Since it is fixed to the bottom part 6c, the sealing part 20 is sealed by the pressure of the liquid handled by the pump.
The second reinforcing portion 23 receives an axial pressing force acting on the bottom portion 20c of the partition wall 6, that is, the sealing portion 20 supports the axially pulling force. Since it is fixed to the flange portion 6a and the bottom portion 6c, it receives a radial pressing force acting on the cylindrical portion 20b of the sealing portion 20 due to the pressure of the pump handling liquid, that is, the sealing portion 20 is pulled in the circumferential direction. This will support the power of

Therefore, the partition wall body 6 has both reinforcing parts 22 and 23 which are constructed together with the sealing part 20 made of a resin material, compared to a partition wall body made only of a resin material and having the same thickness.
However, since it is made of non-magnetic steel, which has a tensile strength at room temperature that is generally one order of magnitude better than resin materials, and whose tensile strength does not decrease as much as resin materials do when temperature rises, the temperature and pressure of the liquid handled by the pump are physical and mechanical strength are significantly improved.

Furthermore, the first reinforcing portion 22 is
Since the rod-shaped reinforcing pieces 24 forming the reinforcing pieces 24 are arranged substantially parallel to each other in the axial direction with gaps 25 provided so that they do not contact each other, the electric resistance in the circumferential direction against eddy currents is extremely high. The second reinforcing portion 23 also includes the cylindrical coil 2 forming this reinforcing portion 23.
8 is wound with a gap 29 provided so that adjacent parts do not come into contact with each other, so the electrical resistance in the axial direction against eddy currents is extremely high.
In addition, the electrical resistance in the radial direction due to the eddy current between the reinforcing parts 22 and 23 is also quite high.In other words, although the reinforcing parts 22 and 23 are in contact with each other, the contact resistance is Both reinforcement parts 22, 23
In general, the number of resistivity of non-magnetic steel is
The value is 100 to several thousand times higher, and therefore, the generation of eddy current in both the reinforcing parts 22 and 23 is extremely suppressed, and non-magnetic steel can be used alone or as a reinforcing material for the resin material. Eddy current loss is drastically reduced compared to the conventional partition wall structure.

In addition, in the embodiment, the first reinforcing portion 2
A gap 25 is provided so that the rod-shaped reinforcing pieces 24 forming the second reinforcing piece 2 do not come into contact with each other, and the second reinforcing part 23
A gap 29 was provided so that the adjacent parts of the cylindrical coil 28 forming the fourth part did not contact each other.
As shown in the figure, even if the cylindrical coil 28 forming the second reinforcing part 23 is tightly wound so that the adjacent parts are in contact with each other without providing the gap 29, and although not shown, the first reinforcing part 23 Even if the rod-shaped reinforcing pieces 24 forming the reinforcing parts 22 are arranged in contact with each other without providing the gap 25, both reinforcing parts 2 in the embodiment described above are
The electrical resistance in the circumferential direction to the eddy current in the first reinforcing portion 22 is increased by the contact resistance of each rod-shaped reinforcing piece 24 so that the electrical resistance to the eddy current between 2 and 23 becomes considerably high due to the contact resistance. Since the axial electrical resistance against eddy current in the second reinforcing portion 23 becomes considerably high due to the contact resistance of the adjacent portions of the cylindrical coil 28, the eddy current loss is approximately the same as in the previous embodiment. can exhibit a reduction effect.

In addition, in this case, since there are no gaps 25, 29 in each of the reinforcing portions 22, 23, the partition wall body 6, although slightly
In addition to further improving the thermal and mechanical strength of
In the first reinforcing part 22, the rod-shaped reinforcing pieces 24 can be easily arranged, and in the second reinforcing part 23, the cylindrical coil 28 can be easily wound.

Note that in both of the above embodiments, the first reinforcing portion 22
In this method, one end of each rod-shaped reinforcing piece 24 was welded to the end plate 26, and the other end was locked to a ring 27 and fixed with a resin curable filler 21. However, as shown in FIG. The flange portion 20a and the bottom portion 20c of the sealing portion 20 may be made thicker and integrally resin-molded with the second reinforcing portion 23 so that the reinforcing pieces 24 having both ends bent are included in the sealing portion 20. In this case, the resin molding often requires a high level of skill, but the complicated operations such as welding and locking each reinforcing piece 24 and injecting the filler 21 as in each of the above embodiments are unnecessary.

In addition, the second reinforcing portion 23 is formed of a cylindrical coil 28 over the entire cylindrical portion 6b of the partition wall 6, and as shown in FIG. 28, both ends of which may be formed with metal rings 31a and 31b, and furthermore, a seventh coil may be used instead of the cylindrical coil 28.
As shown in the figure, a plurality of rings 32 made of non-magnetic steel are formed by sequentially arranging them in the axial direction with gaps 33 provided between adjacent parts, or with adjacent parts abutting each other. can also exhibit similar effects.

Furthermore, the cross-sectional shape of each rod-shaped reinforcing piece 24 of the first reinforcing portion 22 and the cross-sectional shape of the cylindrical coil 28 or each ring 32 of the second reinforcing portion 23 may be any shape other than the above-described embodiments. can be used.

Further, as for the material of the sealing portion 20, in addition to resin, materials with high electrical resistance such as glass, ceramic, and rubber may be used depending on the type and temperature of the liquid handled by the pump. In addition, the thickness of the metal material, which is used in conventional barrier ribs made only of metal materials and is filled to a constant thickness without defective parts, is determined based on the need to maintain thermal and mechanical strength. However, if the thermal and mechanical strength is provided by both reinforcing parts 22 and 23, which are made of metal and have extremely low eddy current loss, as in the present invention, the sealing part 20 has no defects and has a constant thickness. Even if a metal material filled with water is used, the thickness of this metal material can be extremely thin compared to conventional ones, so the eddy current loss in the sealing part 20 can be calculated using the above equation (1). As shown in the figure, the thickness can be made extremely small in proportion to the thickness t.

That is, in the present invention, the sealing portion 20 is not limited to non-metallic materials, but it is also possible to use the same metallic material as in the past, but with the thickness significantly thinner than in the past.

Further, the positional relationship between the reinforcing parts 22 and 23 is not limited to the above embodiment, and the first reinforcing part 22 may be formed outside the second reinforcing part 23.

The embodiments in which the present invention is applied to pumps have been described above, but it can be similarly applied to magnetic couplings for other fluid machines such as blowers and compressors. In addition to synchronous type magnetic couplings that use magnets in the rotor, there are also hysteresis type magnetic couplings that use magnetic hysteresis material for the driven rotor, and highly conductive metal materials such as copper and aluminum for the driven rotor. Of course, the present invention can also be applied to eddy current type magnetic couplings using a squirrel cage rotor and magnetic couplings using DC excitation magnetic poles on the drive side magnet.

〔Effect of the invention〕

As described above, the magnetic coupling partition of the present invention includes a cup-shaped sealing portion for preventing fluid leakage, and a cup-shaped sealing portion for increasing the thermal and mechanical strength of the sealing portion in the axial direction. The first reinforcing part is composed of a first reinforcing part and a second reinforcing part that comes into contact with the first reinforcing part and increases the thermal and mechanical strength of the sealing part in the radial direction. teeth,
A plurality of rod-shaped reinforcing pieces made of a metal material are arranged approximately parallel to the axial direction in a ring shape concentrically around the cylindrical part of the cup-shaped sealing part, and the second reinforcing part is made of a cylindrical coil or a metal material made of a cylindrical coil. By concentrically arranging a plurality of rings made of metal materials arranged sequentially in the axial direction on the cylindrical portion of the cup-shaped sealing portion, chemical strength is improved compared to partitions made only of non-metallic materials such as resin materials. (corrosion resistance) is the same, but has excellent thermal and mechanical strength, and eddy current loss is drastically reduced compared to conventional partition walls that use metal material alone or as a reinforcing material for resin material, greatly increasing transmission efficiency. As a result, the magnetic coupling and drive motor can be miniaturized, which makes it possible to provide them at low cost and reduce operating costs, making them extremely useful in industry.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment in which the present invention is applied to a magnetic coupling pump, Fig. 2 is an enlarged sectional view of the partition body in Fig. 1, and Fig. 3 is a first reinforcing portion of the same partition body. , and FIGS. 4 to 7 are cross-sectional views showing other embodiments of different partition bodies. 3...Magnetic coupling, 6...Cup-shaped partition, 10...Drive side magnet, 11...
Driven side magnet, 15... Driven side rotor, 19
... Magnetic gap, 20 ... Sealing part, 22 ... First reinforcement part, 23 ... Second reinforcement part, 24 ... Rod-shaped reinforcement piece, 25 ... Gap, 28 ... Cylindrical coil, 29
...Gap, 31a, 31b, 32...Ring, 3
3... Gap.

Claims (1)

[Claims] 1. A cup-shaped sealing portion for preventing fluid leakage, a first reinforcing portion for increasing the thermal and mechanical strength of this sealing portion in the axial direction, and this first reinforcing portion. and a second reinforcing part that is in contact with the sealing part and increases the thermal and mechanical strength in the radial direction of the sealing part, and the first reinforcing part is made of a plurality of rod-shaped reinforcing pieces made of metal material. are arranged substantially parallel to the axial direction in a ring shape concentrically around the cylindrical portion of the cup-shaped sealing portion, and the second reinforcing portion is made of a cylindrical coil made of a metal material or a metal material arranged sequentially in the axial direction. A partition body for a magnetic coupling, characterized in that a plurality of rings are arranged concentrically on the cylindrical part of the cup-shaped sealing part. 2. The magnet according to claim 1, characterized in that the second reinforcing portion is formed by abutting adjacent portions of a cylindrical coil or a plurality of rings sequentially arranged in the axial direction. The bulkhead of the coupling ring. 3. A partition wall body for a magnetic coupling according to claim 1 or 2, wherein the first reinforcing portion is formed by abutting adjacent portions of a plurality of rod-shaped reinforcing pieces with each other. .