KR0152975B1 - Magnetic bearing and manufacturing process - Google Patents

Abstract

The present invention discloses a magnetic bearing and a method of manufacturing the same.

The magnetic bearing according to the present invention includes a core in which a plurality of core plates are stacked such that a plurality of poles protrude radially inwardly; A plurality of magnetic coil bodies having coils wound around the poles, respectively; Capacitance sensing means mounted inside the upper portion of the core; Magnetic field for displacement measurement because the capacitance sensor is built in the magnetic bearing so as to be installed in the position closest to the magnetic bearing so as to fix the magnetic coil bodies and the sensing means. Since it is not affected by, it is possible to stably measure the displacement of the rotating shaft by minimizing the measurement error caused by the surface machining error of the rotating shaft, and also to improve the vibration characteristics of the rotating shaft.

Description

Magnetic Bearing and Manufacturing Method

1 is a perspective view showing a magnetic bearing according to the present invention.

2 is a plan view showing a stator core of a magnetic bearing according to the present invention.

Figure 3 (a) is a perspective view showing the coupling and wiring state of the stator core and the magnetic coil body in the magnetic bearing according to the present invention.

(B) of FIG. 3 is a wiring diagram for demonstrating the wiring relationship between magnetic coil bodies.

4 is a perspective view showing a cylinder for a capacitance sensor of a magnetic bearing according to the present invention.

Figure 5 is a perspective view showing the coupling and wiring state of the capacitance sensor in the magnetic bearing according to the present invention.

6 is a perspective view showing a molding state after molding the magnetic bearing according to the present invention into a liquid plastic.

7 is a perspective view showing the state after the cylinder for the capacitance sensor is processed in the magnetic bearing according to the present invention.

* Explanation of symbols for main parts of the drawings

10: stator core 11: pole

12: insulation ring 21-28: magnetic coil body

25s, 27s: starting line 25e, 27e: ending line

30: capacitance sensor 31: sensor plate

32: guard plate 33,34: home

34a: connection part 40: sensor wire

41: guard ship 42: Schilder

50: plastic body L ₁₁ to L ₄₃ : lead wire

S ₂₁ ~ S ₂₈ : Starting point E ₂₁ ~ E ₂₈ : End point

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bearing, and more particularly, to a magnetic bearing in which a capacitance sensor is embedded and a method of manufacturing the same.

The non-contact displacement sensor used to measure the displacement generated during rotation of the shaft is an optical sensor that uses the interference effect of the reflected light according to the medium used for position measurement, and a laser sensor that uses the reflected wave of the laser beam. , A eddy current type sensor that converts the impedance change in the sensor coil due to the eddy current generated on the surface of the conductive metal object into displacement, and the capacitance measuring the distance from the amount of capacitance formed between the conductive object and the sensor plate. Sensor, etc.

However, among these various types of non-contact displacement sensors, a sensor mounted on a magnetic bearing and capable of measuring displacement of the rotating shaft is very limited. This is because of the installation space of the magnetic bearing, the shape of the sensor, and the magnetic field generated from the magnetic bearing. Its use is limited due to influence and the like. In magnetic bearings, eddy current driven displacement sensors are most commonly used for displacement measurement of rotating shafts because eddy current driven displacement sensors are inexpensive and easy to install and use. However, because the eddy current driven displacement sensor is affected by the magnetic field, it should be installed at least 25.4mm from the pole of the stator core. Therefore, the operating position of the magnetic bearing and the measuring position are inconsistent, and the magnetic bearing in the higher order mode of the flexible shaft is installed. There was a problem of this becoming unstable.

In general, the displacement sensors measure only one point of the journal surface, and thus, the machining error and the surface roughness of the journal are mixed with the measured displacement signal, and thus the exact position change of the journal geometric center cannot be measured. This position measurement error is introduced into the control operation of the magnetic bearing controller as it acts as a disturbing factor, causing a problem that makes it difficult to control the exact position of the magnetic bearing.

In addition, the displacement measuring system using a non-contact displacement measuring sensor is not only expensive equipment but also inconvenient to install and use.

The present invention has been made to solve the conventional problems as described above, the capacitance sensor which is not affected by the magnetic field at the time of displacement measurement is mounted in the position as close as possible to the magnetic bearing, due to the surface machining error of the rotating shaft The objective of this invention is to stably measure the displacement of the rotating shaft by minimizing the measurement error, to improve the vibration characteristics of the rotating shaft, and to provide a magnetic bearing that is easy to use.

Another object of the present invention is that the capacitance sensor is molded in a form of liquid plastic and embedded in the magnetic bearing, so that the production of the magnetic bearing is easy to improve the productivity, as well as to reduce the production cost of the magnetic bearing To provide a method of manufacturing.

In order to achieve the above object, a feature of the present invention includes a core in which a plurality of core plates are laminated so that a plurality of poles protrude radially inwardly, and a plurality of magnetic coil bodies having coils wound around the poles, respectively. A magnetic bearing, comprising: capacitance sensing means mounted on an upper inner side of the core; The magnetic bearing includes a plastic body molded from the core, the coil bodies, and the sensing means to fix the magnetic coil bodies and the sensing means.

Another feature of the present invention includes the steps of: connecting and wiring magnetic coil bodies to a plurality of poles of a core in which a plurality of thin core plates are laminated; Bonding capacitance sensing means connected to the four sensors and the guard plates to be separated from each other so as to electrically insulate the upper side of the pole; After the core and the capacitance sensing means are completely bonded, wiring the sensor and the guard wires to the sensor and the guard plates, respectively; Molding a space between the core and the capacitance sensor assembly with liquid plastic; After the molded liquid plastic is solidified, there is a method of manufacturing a magnetic bearing consisting of processing the inner diameter of the capacitance sensor so that the sensor and the guard plate are separated from each other through a turning and grinding process.

Hereinafter, preferred embodiments of a magnetic bearing and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. 1 to 7 are diagrams for explaining the magnetic bearing and the method of manufacturing the same according to the present invention.

First, the magnetic bearing according to the present invention will be described.

Reference numeral 10 denotes a stator core. The stator core 10, as shown in FIG. 1, stacks about 40 to 60 sheets of core plates press-processed with thin silicon steel sheets to prevent heat generation due to eddy current generation. Produce it. Inside the stator core 10, eight poles 11 protrude from each other as a single-axis two-pole controlled two-axis magnetic bearing.

Reference numerals 21 to 28 denote magnetic coil bodies in which an enamel coated copper wire is wound, and the magnetic coil bodies 21 to 28 respectively refer to a starting line at which the winding starts and an end line at which the winding ends, for example, referring to FIG. 3. The coil body 25 has a start line 25s and an end line 25e, and the magnetic coil body 27 has a start line 27s and an end line 27e. In order to prevent the coil from vibrating under the influence of the current controlled by the current amplifying stage (not shown) in the magnetic bearing in the manufacture of the magnetic coil bodies 21 to 28, the windings are fixed between the respective windings. The magnetic coil bodies 21 to 28 are fitted to each other so that the poles 11 of the stator core 10 are bonded to each other by epoxy, and the magnetic coil bodies 21 to 28 are connected to each other to form a horseshoe type electromagnet. To form. In this case, the magnetic coil bodies 21 to 28 push the magnetic fluxes away from each other, such as NN poles or SS poles, to prevent leakage of magnetic flux due to magnetic interaction between adjacent poles 11. Are arranged in the direction.

On the other hand, the magnetic coil bodies 21 to 28 of the magnetic bearing according to the present invention are supplied with power by a single power source. Referring to the symbols with reference to FIG. 3 (b), points S ₂₁ , S ₂₂ ,... S ₂₇ , S ₂₈ are the coil starting points of the magnetic coil bodies 21 to 28, and point E _21. , E ₂₂ , ... E ₂₇ , E ₂₈ are the coil end points of the magnetic coil bodies 21 to 28. In addition, L ₁₁ , L ₂₁ , L ₃₁ , and L ₄₁ are power lines for supplying power to the magnetic coil bodies ₂₁ , ₂₃ , ₂₅ , and ₂₇ , respectively, and wires L ₁₂ , L ₂₂ , L ₃₂ , and L ₄₂ are horseshoees. These are conductors connecting the pair of coil bodies 21, 22, 23, 24, 25, 26, and 27, 28 forming the electromagnet, and the conductors L ₁₃ , L ₂₃ , L ₃₃ And L ₄₃ are the leads connected to the current amplifier stage (not shown) of the controller for magnetic bearings, respectively. Conductor L ₁₁ is a power line that supplies power to the entire magnetic bearing and is continuously connected by conductors L ₂₁ , L ₃₁ , and L ₄₁ so that coil starting points S ₂₁ , S ₂₃ , S ₂₅ , S _27. ), And the conductor L ₁₁ is connected to a DC power supply.

First, referring to the wiring relationship of the pair of first magnetic coil bodies 21 and 22, the conductive wire L ₁₁ is connected to the coil starting point S _{21 of the} magnetic coil body 21 and the magnetic coil body 21. The coil end point E ₂₁ of is connected to the coil starting point S ₂₂ of the magnetic coil body 22 by the conductive wire L ₁₂ . Coil end point (E ₂₂₎ of the magnetic coil 22, the conductor (L ₁₃₎ is connected is connected to the conductor (L ₁₃₎ is follow-up sub-current amplifier stage of a controller for the magnetic bearings and the vertical axis (not shown).

In addition, in the pair of second magnetic coil bodies 23 and 24, the conductive wire L ₂₁ is connected to the coil starting point S _{23 of the} magnetic coil body 23, and the coil end point of the magnetic coil body 23 ( E ₂₃ ) is connected to the coil starting point S ₂₄ of the magnetic coil body 24 by a conductor L ₂₂ . The coil end point (E _24), the wire (L ₂₃₎ of the magnetic coil 24 is connected and is connected to the conductor (L ₂₃₎ is follow-up sub-current amplifier stage of a controller for the horizontal magnetic bearing (not shown).

In the pair of third magnetic coil bodies 25 and 26, the conductive wire L ₃₁ is connected to the coil starting point S _{25 of the} magnetic coil body 25 and the coil end point of the magnetic coil body 25 ( E ₂₅ ) is connected to the coil starting point S ₂₆ of the magnetic coil body 26 by a conductor L ₃₂ . The coil end point (E _26), the wire (L ₃₃₎ of the magnetic coil 26 is connected is connected to the conductor (L ₃₃₎ is a half of all for the vertical axis control magnetic bearing current amplification stage (not shown).

Finally, in the pair of fourth magnetic coil bodies 27 and 28, the conductor L ₄₁ is connected to the coil starting point S _{27 of the} magnetic coil body 27 and the coil end point of the magnetic coil body 27. E ₂₇ is connected to the coil starting point S ₂₈ of the magnetic coil body 28 by a conductor L ₄₂ . The coil end point (E _28), the wire (L ₄₃₎ of the magnetic coil 28 is connected is connected to the conductor (L ₄₃₎ are all half of the controller for the horizontal magnetic bearing current amplification stage (not shown).

Reference numeral 30 denotes a cylindrical capacitance sensor made of brass. The capacitance sensor 30 is bonded to the upper side of the poles 11 so as to be electrically insulated, as shown in FIG. Here, an insulation ring 12 having a thickness of about 1 mm is interposed between the poles 11 of the stator core 10 and the capacitance sensor 30 for electrical insulation. The capacitance sensor 30 is composed of four sensor plates 31 and guard plates 32 which are separated from each other by maintaining a constant gap therebetween. The sensor plate 31 and the guard plate 32 of the capacitance sensor 30 are disposed at an angle of 90 ° with respect to two directions of vertical and horizontal, and the areas of the sensor plate 31 and the guard plate 32 are mutually different. It is intended to be the same.

Reference numerals 40 and 41 denote sensor lines and guard lines as signal lines of the capacitance sensor 30. As shown in FIG. 5, the sensor lines 40 are wired to the sensor plates 31, respectively, and the guard lines 41 are shown. Are wired to the guard plates 32, respectively. The sensor and guard wires 40 and 41 may preferably use low resistance single wires covered with Teflon material. These sensors and guard wires 40 and 41 are all used in a shielded form and are twisted and twisted in a mesh form to cross in opposite directions. Accordingly, the sensor and the guard wires 40 and 41 cancel each other by rotating in opposite directions, and eight sensors in all sections from the sensor and guard plates 31 and 32 to the sensor amplifier (not shown). The guard lines 40 and 41 can maintain the same ground level and noise level. In this case, the sensor and the guard wire (40, 41) is preferably a total length does not exceed 1m.

Reference numeral 50 denotes a plastic body, and as shown in FIG. 6, the plastic body 50 is formed by solidifying a liquid plastic in an empty space between the stator core 10 and the capacitance sensor 30 assembly. By the plastic body 50, the magnetic coil bodies 21 to 28 and the capacitance sensor 30 are firmly fixed to the stator core 10, respectively. Herein, the plastic body 50 is preferably molded in the magnetic coil bodies 21 to 28 exposed to the lower portion of the stator core 10. At this time, the plastic body 50 eliminates typical noise phenomena generated when the stator core 10 and the magnetic coil bodies 21 to 28 are bonded by epoxy.

As described above, the magnetic bearing according to the present invention uses the capacitance of the object, that is, the displacement of the rotation axis (not shown) by using the amount of charge integrated between the sensor plates 31 and the rotation axis. Because of the measurement, the position can be measured accurately regardless of the machining state of the rotary shaft. In addition, since the capacitance sensor 30 which is not affected by the magnetic field is mounted at the position as close as possible to the stator core 10, the displacement of the rotating shaft can be stably measured by minimizing the measurement error caused by the surface machining error of the rotating shaft. In addition, the vibration characteristics of the rotating shaft are improved. In addition, the magnetic bearing according to the present invention can eliminate a very complicated measurement error removal process such as the initial rotation error removal process or low pass filtering according to the rotational speed used in a general magnetic bearing system, and the capacitance when using the magnetic bearing. It is possible to use the product such as to reduce the time required to align the alignment with the sensor 30.

Referring to the manufacturing method of the magnetic bearing according to the present invention.

First, as shown in FIG. 3, the magnetic coil bodies 21 to 28 wound around the poles 11 of the stator core 10 in which a plurality of thin silicon steel sheets are stacked are bonded by epoxy to bond. . The wires L ₁₁ to L _{43 are} connected to the start points S ₂₁ to S ₂₈ and the end points E ₂₁ to E _{28 of} the magnetic coil bodies ₂₁ to ₂₈ , respectively, and the electric power is simultaneously connected. Connect the supply line (L ₁₁ ) to the power supply.

On the other hand, the cylindrical capacitance sensor 30 is mounted on the upper side of the pole 11 of the stator core 10 so as to electrically insulate. Here, as shown in FIG. 4, the capacitance sensor 30 has rectangular grooves 33 formed so that the four sensors and the guard plates 31 and 32 are divided from each other. In addition, the capacitance sensor 30 is also formed with grooves 34 having a connecting portion 34a such that the guard plates 32 are divided from each other. In this case, the grooves 33 and 34 are preferably formed to have a narrow width and a deep depth.

After the stator core 10 and the capacitance sensor 30 are completely adhered as described above, as shown in FIG. 5, the sensor and the guard wires are formed on the sensors and the guard plates 31 and 32 of the capacitance sensor 30. Wire 40 and 41, respectively.

When the wiring of the sensors and the guard wires 40 and 41 is completed, as shown in FIG. 6, the empty space between the stator core 10 and the capacitance sensor 30 assembly is molded by liquid plastic to solidify the plastic body. To form (50). In the case of molding with the above liquid plastic, an appropriate molding mold is produced and used, and the magnetic coil bodies 21 to 28 exposed to the lower part of the stator core 10 are molded by the plastic body 50.

In addition, after the molded liquid plastic is solidified, the inner diameter of the capacitance sensor 30 is processed so that the sensor and the guard plates 31 and 32 are separated from each other through a turning and grinding process. At this time, when processing the inner diameter of the capacitance sensor 30, as shown in Figure 7, the grooves 33, 34 are processed to be completely removed, the sensor and guard due to the removal of the grooves (33, 34) The plates 31 and 32 are separated from each other so as to maintain a constant gap with each other.

On the other hand, after processing the inner diameter of the capacitance sensor 30 as described above, the surface of the sensor plate 31 and the guard plate 32 is subjected to an enamel coating coating, whereby the sensor plate 31 and the guard plate The field 32 prevents a phenomenon in which the sensing signal is disconnected by a moment by the electrical contact between the sensor plates 31 and the rotating shaft due to a sudden disturbance that may occur during the rotation of the rotating shaft due to the coating treatment. Accordingly, in the manufacturing method of the magnetic bearing according to the present invention, since the capacitance sensor 30 is molded by liquid plastic and embedded in the magnetic bearing, the structure of the magnetic bearing is simple and its manufacture is easy, thereby improving productivity. In addition, the production cost of the product is reduced.

In the above embodiments, the preferred embodiments of the present invention are described, but the scope of application of the present invention is not limited to the above embodiments, and the specific shapes and structures shown in the above embodiments are in the embodiments of the present invention. It is merely shown a specific example, the present invention can be appropriately changed within the scope of the same idea in addition to these embodiments.

As described above, the magnetic bearing and the manufacturing method thereof according to the present invention can stably measure the displacement of the rotating shaft, and the vibration characteristics of the rotating shaft are improved and the use of the product is convenient. In addition, the production of magnetic bearings is easy to improve productivity as well as to reduce the production cost of the product.

Claims (9)

A magnetic bearing comprising a core in which a plurality of core plates are laminated so that a plurality of poles protrude radially inward, and a plurality of magnetic coil bodies wound around coils to be coupled to the poles, respectively. Capacitance sensing means mounted to the; And a plastic body formed by molding the core, the coil bodies, and the sensing means to fix the magnetic coil bodies and the sensing means. The magnetic bearing as claimed in claim 1, wherein the sensing means is composed of four capacitance sensors which are divided and disposed at an angle of 90 degrees. The magnetic bearing according to claim 2, wherein each of the capacitance sensors has a rectangular sensor plate formed at a central portion thereof, and a guard plate surrounding the sensor plate with a predetermined gap with the sensor plate. 4. The magnetic bearing according to claim 3, wherein the sensor plate and the guard plate are each wired with a sensor wire and a guard wire wound in a mesh shape so as to be shielded and continuously intersect in opposite directions. The magnetic bearing of claim 1, wherein an insulation ring is interposed between the core and the sensing means for electrical insulation. The magnetic bearing according to claim 1 or 5, wherein the plurality of magnetic coil bodies are powered by a single power source. Coupling and coupling magnetic coil bodies to a plurality of poles of a core in which a plurality of thin core plates are stacked; Bonding capacitance sensing means connected to the four sensors and the guard plates to be separated from each other so as to electrically insulate the upper side of the pole; After the core and the capacitance sensing means are completely bonded, wiring the sensor and the guard wires to the sensor and the guard plates, respectively; Molding a space between the core and the capacitance sensor assembly with liquid plastic; And after the molded liquid plastic is solidified, processing the inner diameter of the capacitance sensor such that the sensor and the guard plates are separated from each other through a turning and grinding process. The method of manufacturing a magnetic bearing according to claim 7, wherein in the molding of the liquid plastic, the magnetic coil body exposed to the lower portion of the stator core is molded by the liquid plastic. The method of manufacturing a magnetic bearing according to claim 7, further comprising enameling the surfaces of the sensor plates and the guard plates after processing the inner surface of the capacitance sensor.