JP2007227784A - Electromagnet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnet device which can be intended to reduce a reservoir tank in size for an insulating oil to be used as a cooling medium or to remove it, and can be easily manufactured. <P>SOLUTION: A part of a volume of the insulating oil in a casing is replaced with a substantial body which does not preclude a convection of the insulating oil, whereby a space which has need for an airtight property with respect to the insulating oil is not formed in the casing. A use amount of the insulating oil is intended to curtail, whereby an influence of a volume change according to a thermal change of the insulating oil is decreased. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnet apparatus suitable for use as a magnetic source of a magnetic apparatus such as a lifting electromagnetic apparatus or a magnetic selector.

  In a large electromagnet device such as a lifting electromagnet device, the exciting coil generates heat by supplying a large current to the exciting coil. When the temperature of the exciting coil rises, the electrical resistance increases accordingly, so that the exciting current decreases and the exciting force decreases. Moreover, the use efficiency of electric power also falls by the increase in the electrical resistance of an exciting coil. For this reason, various proposals have been made to cool the electromagnet device and effectively suppress the temperature rise of the exciting coil.

It has been proposed to use water as a cooling medium for an exciting coil of an electromagnet device (see, for example, Patent Document 1). In addition, it has also been proposed to use an insulating oil used in a high-voltage electric device such as a transformer as a cooling medium for an electromagnet device (see, for example, Patent Document 2).
Furthermore, it has been proposed to fill a space between the exciting coil and the yoke or the magnetic pole member with a filler having high thermal conductivity to promote the dissipation of heat generated in the exciting coil (for example, see Patent Document 3). .

Japanese Utility Model Publication No. 5-95008 Japanese Patent Application Laid-Open No. 2002-177813 Japanese Patent Laid-Open No. 10-231085

  However, the cooling method using water as a cooling medium (Patent Document 1) requires a water channel or a water tank to ensure electrical insulation between the exciting coil and the cooling medium, and also requires countermeasures against corrosion and leakage. , Not easy to manufacture. Moreover, in the method (patent document 3) of filling a filler having high thermal conductivity, it is necessary to use an epoxy resin material blended with alumina powder as the filler and fill the resin material around the exciting coil. Therefore, vacuum technology is indispensable, and manufacturing is not easy.

  On the other hand, in the method using an insulating oil as a cooling medium (Patent Document 2), the insulating oil is casing without causing corrosion and leakage problems and without using a vacuum technique for filling the casing with the insulating oil. Can be filled inside. Moreover, there is an advantage that the temperature rise of the exciting coil can be suitably suppressed by the convection of the insulating oil accompanying the temperature rise of the exciting coil.

  However, a large reservoir tank is required to compensate for the volume change due to the thermal expansion and contraction of the insulating oil accompanying the temperature change of the insulating oil, which leads to an overall increase in the size of the electromagnet device. Result. Further, by forming a space portion as shown in Patent Document 2 in the casing, the volume of the insulating oil can be reduced, but it is necessary to reliably prevent the intrusion of the insulating oil into the space portion. In addition, it takes time to form an airtight space, and its manufacture is not easy.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnet device that can reduce the size of a reservoir tank without compromising the advantage of using insulating oil as a cooling medium and that is relatively easy to manufacture.

  The present invention replaces a part of the volume of the insulating oil with a solid body that does not prevent the convection of the insulating oil, thereby reducing the amount of the insulating oil used. Based on the concept of reducing the effect of the volume change.

  Therefore, an electromagnet device according to the present invention includes an iron core disposed in a casing, an excitation coil surrounding the iron core and disposed in the casing, and an insulation filled in the casing so as to be in contact with the excitation coil. Oil and an insulation that is disposed in the casing and has a coefficient of thermal expansion smaller than the value of the coefficient of thermal expansion of the insulating oil, and that occurs when the insulating oil is heated by energizing the exciting coil. And a solid body that reduces the filling amount of the insulating oil without preventing oil convection.

  In the electromagnet device according to the present invention, when the insulating oil is heated by energizing the exciting coil, the solid oil disposed in the casing does not prevent the convection of the insulating oil in the casing. The amount of heat of the exciting coil is efficiently discharged from the casing to the outside through the insulating oil by the convection.

  In addition, the solid body can reliably reduce the capacity of the insulating oil, for example, by simply positioning it in the gap between the casing and the exciting coil without considering the airtightness against the insulating oil such as the space. Easy to manufacture. Moreover, since such a solid body exhibits higher thermal conductivity than the space portion shown in Patent Document 2, it is extremely advantageous in improving heat dissipation from the insulating oil. Moreover, even if a material having a thermal conductivity lower than that of insulating oil is used as the solid body, for example, overheating of the exciting coil can be effectively prevented by convection of insulating oil.

  As described above, the amount of the insulating oil contained in the casing can be reduced according to the volume of the solid body by simply arranging the solid body of the present invention in the casing. Since the solid body replaced with the insulating oil of the part has a lower coefficient of thermal expansion than the insulating oil, the amount of insulating oil in the casing is reduced without forming a space part in the casing as in the prior art. The amount of change in the volume of the insulating oil due to the heat change can be reduced by reducing the insulating oil.

  Accordingly, the reservoir tank for retaining excess insulating oil that overflows from the casing when the insulating oil is at a high temperature can be easily reduced without forming a space in the casing as in the prior art. The reservoir tank can be made unnecessary by increasing the capacity of the solid body to such an extent that the capacity change accompanying the heat change of the insulating oil can be substantially ignored. It is possible to easily reduce the overall size of the electromagnet device without impairing the effect.

  The solid body can be made of, for example, a heat-resistant synthetic resin material such as silicone, a glass material, a copper alloy such as brass, or a metal material such as aluminum.

  The solid body can be formed into a large number of spherical bodies such as marbles, and these can be arranged so as to be statically held in the casing. In this case, since the insulating oil flows through the gaps between the spherical bodies, the convection of the insulating oil is not prevented by these spherical bodies, so the amount of heat of the exciting coil passes through the insulating oil that generates the convection. It is released properly outside.

  In order to statically hold each spherical body in the casing, the spherical body can be sized or weighted so as not to cause convection with the insulating oil.

  The solid body can be formed of a plurality of blocks that are spaced from the excitation coil without interfering with the convection of the insulating oil along the excitation coil. This block can be made of the same material as described above.

  Convection of the insulating oil due to heat from the excitation coil occurs along the surface of the excitation coil. The block-shaped solid body spaced from the exciting coil does not interfere with the convection generated along the surface of the exciting coil, so that the amount of heat of the exciting coil is appropriately outside the casing through the insulating oil that generates the convection. Released.

  A large number of holes for allowing the convection of the insulating oil can be formed in each block, whereby the convection of the insulating oil can be more reliably ensured.

  As the casing, an inner peripheral wall surrounding the iron core may be provided, and the inner peripheral wall may be a casing having a polygonal cross-sectional shape surrounding the iron core. In this case, the solid body can be disposed at each corner of the inner peripheral wall.

  It is preferable to use the solid body disposed at the corner of the casing that exhibits a thermal conductivity larger than the thermal conductivity of the insulating oil.

  The solid body arranged at the corner of the casing may be one that exhibits a thermal conductivity smaller than the thermal conductivity of the insulating oil. In this case, the insulating oil is forcibly circulated. It is desirable to provide a forced circulation mechanism to enhance the heat dissipation effect due to convection.

  Particles that circulate together with the insulating oil due to the convection of the insulating oil can be mixed into the insulating oil as a solid. These particles can be formed of a heat-resistant synthetic resin material such as silicone, a glass material, a copper alloy such as brass, and a metal material such as aluminum. The solid body made of this metal material is preferably coated with an insulating material such as resin in order to more reliably prevent leakage due to contact with the exciting coil.

  The exciting coil includes a plurality of annular coil portions arranged in a stack around the iron core, and the annular coil portions arranged in a stack so as to secure a gap between the annular coil portions adjacent to each other in the stacking direction. It can be comprised with the spacer arrange | positioned between. Since the insulating oil can be made to flow between the annular coil portions by the spacer, the cooling effect of the exciting coil can be further enhanced. The spacer can be formed using, for example, the solid material.

  A magnetic casing that is open at one end is used as the casing, the iron core is magnetically coupled to the casing in the casing, and the open end of the casing is closed with a nonmagnetic bottom plate for sealing the inside of the casing. Can do.

  According to the present invention, as described above, the convection of the insulating oil generated when the insulating oil is heated by energizing the exciting coil is not prevented by the solid body disposed in the casing. Since part of the insulating oil is replaced by the above, a space portion that requires high airtightness against the insulating oil is not formed in the casing, and therefore the amount of the insulating oil used can be easily reduced. Therefore, the influence of the volume change accompanying the heat change of the insulating oil can be reduced.

  In addition, it is possible to easily reduce the size of the reservoir tank for the insulating oil or eliminate the need for the reservoir tank without forming a space in the casing that requires high airtightness against the insulating oil. Thus, it is possible to easily reduce the overall size of the electromagnet device without impairing the cooling effect of the electromagnet device.

  Hereinafter, the present invention will be described with reference to the illustrated embodiments.

  The external appearance of the electromagnet device 10 according to the present invention is shown in FIGS. 1 (a) to 1 (c). The electromagnet device 10 is a cooling device connected to the electromagnet main body 12 via a rectangular electromagnet main body 12 and a pair of connecting pipes 14 in the illustrated example. A reservoir tank 16 for the medium. As is well known in the art, the reservoir tank 16 stores excessive cooling insulating oil that overflows from the electromagnet body 12, and is more replete than the electromagnet body so that the stored insulating oil is supplied into the electromagnet body 12. It is held in the upper position.

  As shown in FIGS. 2 and 3, the electromagnet main body 12 has a casing 18 made of a magnetic material having a rectangular shape whose lower end is opened, and a non-sealing chamber 20 that closes the open end of the casing and defines an airtight chamber 20 in the casing. A bottom plate 22 made of a magnetic material, a columnar iron core 24 arranged in the hermetic chamber 20, and an excitation coil 26 arranged around the iron core 24 in the casing 18 are provided.

  In the illustrated example, the casing 18 includes a square top portion 18a (see FIG. 3) and a rectangular peripheral wall portion 18b extending downward from an outer edge of the top portion. In the illustrated example, the iron core 24 is formed of a magnetic cylinder having a circular cross-sectional shape, and is arranged with one end abutting on the central portion of the top portion 18 a of the casing so as to be magnetically coupled to the casing 18. The lower end thereof is located on the same plane as the lower edge of the peripheral wall portion 18b. The iron core 24 can be formed integrally with the casing 18.

  The nonmagnetic bottom plate 22 is disposed so as to cover the lower end of the iron core 24 and the lower edge of the peripheral wall portion 18 b of the casing 18, and is fixed to the casing 18.

  In the illustrated example, the exciting coil 26 disposed around the iron core 24 includes a plurality of annular coil portions 26a. These coil portions 26a are disposed in a laminated manner between upper and lower annular seat plates 28a, 28b made of an insulator disposed at a portion where the top portion 18a of the casing 18 and the bottom plate 22 face each other. Instead of this annular seat plate, linear seat plates can be arranged radially.

  As shown in FIG. 3, between the coil portions 26a adjacent in the vertical direction, as shown in FIG. 2, they are spaced radially from each other in the circumferential direction of the coil portion 26a along the radial direction of the coil portions. A plurality of spacer members 30 made of an arranged insulator are arranged, and these are fixed in the hermetic chamber 20 through fixing bolt assemblies 32. Thus, a gap is secured between adjacent coil portions 26 a arranged in a stacked manner in a region excluding the spacer member 30, and the inner peripheral surface and outer peripheral surface of each coil portion 26 a are the peripheral surfaces of the iron core 24. All coil portions 26a are fixed at intervals from the peripheral wall portion 18b of the casing 18. The coil portions 26a are connected in series to each other so that the lower end of the iron core 24 acts as one magnetic pole surface and the lower edge of the peripheral wall portion 18b acts as the other magnetic pole surface by supplying current to them.

  The excitation coil 26 can be constituted by a single excitation coil without being divided into a plurality of coil portions 26a. However, in order to enhance the cooling effect of the excitation coil 26 by insulating oil 34 described later, as shown in the figure, It is desirable that the plurality of coil portions 26a are stacked at intervals.

  As shown in FIGS. 4 and 5, the hermetic chamber 20 is filled with a well-known cooling insulating oil 34, and a part of the insulating oil is stored in the reservoir tank 16 as described above. It is possible to go in and out.

  When the exciting coil generates heat by energizing the exciting coil 26, convection occurs in the insulating oil 34 in the hermetic chamber 20 due to the heat generated from the exciting coil. This state of convection is indicated by arrows 34a in FIGS.

  As is apparent from FIG. 4 in which the inside of the hermetic chamber 20 is viewed in a vertical cross section, between the coil portions 26a that are heat generation sources, the flow of the insulating oil 34 toward the inner and outer peripheral surfaces of the coil portions 26a These flow upward as a whole along the inner and outer peripheral surfaces of the exciting coil 26. The upward flow of the insulating oil 34 reaching the top portion 18a of the casing 18 flows toward the peripheral wall portion 18b of the casing 18, as shown by a flow 34a of 34 shown in FIG. As the temperature drops, a downward flow is generated along the peripheral surface of the iron core 24 and the peripheral wall portion 18b of the casing 18 which are separated from the peripheral surface of the exciting coil 26. Due to the convection 34a of the insulating oil 34, the amount of heat of the exciting coil 26 is transmitted to the iron core 24 and the casing 18, and is radiated into the atmosphere, so that overheating of the exciting coil 26 is suitably prevented.

  Referring again to FIG. 5 showing the flow 34a of the insulating oil 34, a relatively strong flow of the insulating oil 34 is generated in a portion where the distance between the outer peripheral surface of the exciting coil 26 and the peripheral wall portion 18b of the casing 18 is narrow. The insulating oil 34 does not flow so strongly at the corners of the peripheral wall 18b where the interval is widened.

  In the electromagnet device 10 according to the first embodiment of the present invention, the solid body 36 as shown in FIG. 2 is arranged at the corner of the peripheral wall 18b where the flow of the insulating oil 34 is gentle, that is, the corner of the hermetic chamber 20. ing.

  The solid body 36 is a block of right triangular prisms having adjacent right side sides 36a and 36a along the straight line of the peripheral wall portion 18b and a hypotenuse side 36b spaced from the outer peripheral surface of the exciting coil 26. The block-shaped solid body 36 is made of a heat-resistant synthetic resin material such as silicone, a glass material, a copper alloy such as brass, or a metal material such as aluminum that exhibits a thermal expansion coefficient smaller than that of the insulating oil 34. Can be configured.

  Such a solid body 36 exhibits a thermal conductivity larger than that of the insulating oil 34, and does not exhibit a heat blocking function as in the conventional hollow chamber of the space, and from the insulating oil 34 to the casing 18. It also acts to promote heat conduction. Therefore, the solid body 36 that does not prevent the convection of the insulating oil 34 can be made of a material that has a thermal conductivity equal to or smaller than the thermal conductivity of the insulating oil 34. As described above, In terms of promoting heat conduction from the insulating oil 34 to the casing 18, it is desirable to select a material that exhibits a thermal conductivity greater than that of the insulating oil 34.

  Since the block-shaped solid body 36 showing a thermal expansion coefficient smaller than the thermal expansion coefficient of the insulating oil 34 is arranged in a portion where the flow of the insulating oil 34 is gentle as described above, insulation is achieved by the arrangement of the solid body. The convection of the insulating oil 34 is not hindered to such an extent that the cooling action of the exciting coil 26 due to the convection of the oil 34 is substantially reduced.

  Further, since the solid body 36 having a thermal expansion coefficient smaller than the thermal expansion coefficient of the insulating oil 34 replaces a part of the volume of the insulating oil 34 by its volume, the insulating oil 34 filled in the hermetic chamber 20 is replaced with the solid body 36. The capacity is reduced, and accordingly, the volume increase due to the thermal expansion of the insulating oil 34 is reduced. Therefore, the amount of the insulating oil 34 flowing out from the hermetic chamber 20 into the reservoir tank 16 due to the thermal expansion of the insulating oil 34 in the hermetic chamber 20 can be reduced according to the capacity of the solid body 36. The capacity can be made smaller than before, and the size can be reduced.

  In order to ensure the convection of the insulating oil 34, a large number of holes can be formed in the solid body 36, or the solid body 36 can be formed of a porous body.

  In the above description, a cylinder is used as the iron core 24. However, as shown in FIG. In this case, the excitation coil 26 has a rectangular planar outer shape as a whole, but the corners corresponding to the corners of the peripheral wall portion 18b of the casing 18 are rounded, so that the solid body 36 similar to that shown in FIG. It can be arranged at each corner of the closed chamber 20.

  As the solid body 36, as shown in FIGS. 7A and 7B, a solid body composed of a large number of spherical bodies 36 can be used. Such a spherical body 36 can be formed of the same material as that of the block shape described above. Basically, the spherical body 36 has a size and a size so as not to move due to the convection of the insulating oil 34. It only has to be given weight.

  Moreover, as the particle size of the solid body 36, for example, by using spherical bodies having various particle sizes of several cm to several tens of cm, the inside of the hermetic chamber 20 can be used without using a vacuum means as in the filling of the liquid synthetic resin material. The solid body 36 can be inserted into the core 24 and the exciting coil 26 and between the coil portions 26a constituting the exciting coil 26 (FIG. 7) so that the granular bodies 36 do not move. This can be filled. In such a spherical body 36, a continuous gap allowing the convection of the insulating oil 34 is formed between the adjacent spherical bodies, so that the cooling effect of the exciting coil 26 due to the convection of the insulating oil 34 is impaired. There is no.

  Further, the hermetic chamber 20 can be partitioned by a net (not shown), and the solid body 36 made of a spherical body can be disposed in the partitioned required area.

  The solid body 36 made of such a spherical body can be made of a material having a value smaller than the thermal conductivity of the insulating oil 34. However, in this case, in order to promote heat conduction from the insulating oil 34 to the casing 18, as shown in FIGS. 8A and 8B, the insulating oil 34 is forcedly circulated in the hermetic chamber 20. It is desirable to provide the forced circulation mechanism 38.

  The forced circulation mechanism 38 is provided on the opposite side of the electromagnet body 12 from the side where the reservoir tank 16 is provided, and one end is opened to the hermetic chamber 20 (see FIG. 7B) above the peripheral wall portion 18b of the electromagnet body 12. And an inclined guide pipe 38a whose other end opens to the hermetic chamber 20 below the peripheral wall portion 18b, and a pressurizing pump 38b that pumps the insulating oil 34 from the one end of the inclined guide pipe toward the other end. . The forced circulation mechanism 38 enhances the cooling effect on the insulating oil 34 by promoting the flow of the insulating oil 34 shown in FIG. 4 by the pumping action of the insulating oil 34 in the pressurizing pump 38b.

  Depending on the amount of replacement of the solid body 36, the amount of use of the insulating oil 34 can be reduced, so that the increase or decrease in capacity due to the thermal expansion of the insulating oil can be greatly reduced, thereby making the reservoir tank 16 unnecessary. It is also possible.

  Further, instead of the two examples described above, particles that circulate in the hermetic chamber 20 together with the insulating oil along with the convection can be mixed into the insulating oil 34 as the solid body 36. The particles 36 can be formed of a heat-resistant synthetic resin material such as silicone, a glass material, a copper alloy such as brass, and a metal material such as aluminum. The particles 36 made of the metal material are desirably coated with an electrically insulating material such as a resin material.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. Further, the present invention can be used as a magnetic source of various magnetic devices such as a lifting electromagnet device or a magnetic sorter.

The external appearance of the electromagnet apparatus which concerns on this invention is shown, (a) is a top view, (b) is a front view, (c) is a side view. It is sectional drawing obtained along the II line | wire shown in FIG.1 (b). It is sectional drawing obtained along the II-II line | wire of FIG. It is the same cross section as FIG. 3 which shows the basic flow of the insulating oil in the electromagnet apparatus which concerns on this invention. It is a partial plane sectional view which shows the basic flow of the insulating oil in the electromagnet apparatus which concerns on this invention except a solid body. It is drawing similar to FIG. 2 which shows the other Example of the electromagnet apparatus based on this invention. FIG. 4 shows still another embodiment of the electromagnet device according to the present invention, wherein (a) is a drawing similar to FIG. 2, and (b) is a cross section obtained along the line III-III shown in FIG. FIG. The external appearance of the further another Example of the electromagnet apparatus based on this invention is shown, (a) is a top view, (b) is a front view, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electromagnet apparatus 12 Electromagnet main body 18 Casing 20 Airtight chamber 22 Bottom plate 24 Iron core 26 Excitation coil 26a Annular coil part 30 Spacer member 34 Insulating oil 36 Solid body 38 Forced circulation mechanism

Claims (11)

  An iron core disposed in the casing, an excitation coil surrounding the iron core and disposed in the casing, an insulating oil filled in the casing so as to be in contact with the excitation coil, and disposed in the casing, The insulating oil has a coefficient of thermal expansion smaller than the value of the coefficient of thermal expansion of the insulating oil, and the insulation without preventing convection of the insulating oil that occurs when the insulating oil is heated by energizing the exciting coil. An electromagnet device including a solid body that reduces oil filling amount.   2. The electromagnet according to claim 1, wherein the solid body is a spherical body that is a large number of spherical bodies that are statically held in the casing and that forms gaps that allow the flow of the insulating oil between the spherical bodies. apparatus.   The electromagnet device according to claim 2, wherein each of the spherical bodies has a size or a weight that does not cause movement with the convection of the insulating oil.   The electromagnet apparatus according to claim 1, wherein the solid body includes a plurality of blocks arranged at intervals from the excitation coil without interfering with convection of the insulating oil along the excitation coil.   The electromagnet apparatus according to claim 4, wherein a plurality of holes for allowing convection of the insulating oil are formed in each block.   The casing includes an inner peripheral wall surrounding the iron core, the inner peripheral wall has a polygonal cross-sectional shape surrounding the iron core, and the solid body is disposed at each corner of the inner peripheral wall. 4. The electromagnet device according to 4.   The electromagnet device according to claim 6, wherein the solid body has a thermal conductivity larger than that of the insulating oil.   The electromagnet device according to claim 6, wherein the solid body has a thermal conductivity smaller than that of the insulating oil, and further includes a forced circulation mechanism for forcibly circulating the insulating oil.   The electromagnet apparatus according to claim 1, wherein the insulating oil includes particles that circulate together with the insulating oil in accordance with convection of the insulating oil.   The exciting coil surrounds the iron core with a plurality of annular coil portions arranged in a stacked manner, and between the annular coil portions arranged in a laminated shape so as to secure a gap between the annular coil portions adjacent to each other in the stacking direction. The electromagnet device according to claim 1, further comprising a spacer disposed on the magnet.   The casing is a magnetic casing that is open at one end, and the iron core is magnetically coupled to the casing in the casing, and the open end of the casing is closed by a nonmagnetic bottom plate to seal the inside of the casing. The electromagnet device according to claim 1.

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