Reactor including tubular core, motor drive device, and amplifier device

A reactor capable of eliminating a heat source provided within a power cabinet housing a motor drive device. The reactor includes a tubular core, a coil installed inside the core, a terminal which is provided at an axially first end of the core and which is connected to the coil, and an attachment flange which extends radially outside of the core and which is provided between the terminal and a second end of the core.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a reactor including a tubular core, a motor drive device, and an amplifier device.

2. Description of the Related Art

In a machine tool or industrial machine, a motor drive device (including a converter, an inverter, and a reactor) for driving a motor used for a robot, the reactor disposed between the converter of the motor drive device and a power source is generally installed in a power cabinet.

Peripheral equipment including a motor drive device installed in the power cabinet, or cables generate heat, and accordingly, the internal temperature of the power cabinet reaches 40° C. to 50° C. in some cases. Thus, an air duct for ventilation and a cooler may be provided to prevent the motor drive device or peripheral equipment from excessively generating heat.

The quantity of heat generated from the motor drive device, the peripheral equipment, and the cables in the power cabinet is referred to as the residual heat quantity, and is used as a criterion with reference to which the temperature of the power cabinet in operation is designed so as to remain within a predetermined temperature range.

In many cases, the quantity of heat generated from the motor drive device (including the converter, the inverter, and the reactor) contained in the power cabinet accounts for most of the quantity of heat generated in the power cabinet. However, a heat radiator is provided for the converter and the inverter. Disposing the heat radiator so as to project to the outside of the power cabinet enables drastic reduction of the residual heat quantity.

The reactor is usually disposed within the power cabinet, and does not have a heat radiation means extending to the outside of the power cabinet. Thus, the quantity of heat generated from the reactor accounts for all the residual heat quantity, and contributes to a rise in the temperature of the power cabinet.

This remarkably increases the ratio of the residual heat quantity caused by the reactor to the total residual heat quantity in the power cabinet in proportion to the output of the motor drive device. As a technology for releasing the residual heat generated from the reactor to the outside of the power cabinet, disposing the reactor outside the power cabinet has been known (see, e.g., Japanese Unexamined Patent Publication (Kokai) No. 2010-130779).

Conventionally, a technology for eliminating the heat source within the power cabinet containing the motor drive device has been demanded.

SUMMARY OF THE INVENTION

In an aspect of the invention, a reactor includes a tubular core, a coil provided in the core, a terminal provided at an first end of the core in an axial direction and to which the coil is connected, and an attachment flange extending radially outside of the core and disposed at a position between the terminal and a second end of the core opposite the first end.

The attachment flange may be disposed at a position between the terminal and the first end, or at a position between the first end and the second end to be closer to the first end than the second end. The reactor may further include a sealing section provided at the second end so as to hermetically seal the inside of the core.

The reactor may further include a sealing section provided at an end face of the attachment flange in the axial direction so as to surround the outer surface of the core. The attachment flange is formed with a handle provided so as to project from the attachment flange in the axial direction or a fastening section for fastening an eyebolt.

In another aspect of the invention, a motor drive device includes the above-mentioned reactor. In still another aspect of the invention, an amplifier device includes a hollow power cabinet having a wall formed with a through-hole, and the above-mentioned reactor, wherein the core is disposed in the through-hole so that the second end is exposed to the outside of the power cabinet, while the terminal is located inside of the power cabinet, and the attachment flange is fixed to the wall so as to close the through-hole.

DETAILED DESCRIPTION

Embodiments of the invention will be described below with reference to the drawings. Note that, in various embodiments described below, similar elements are assigned the same reference numerals, and overlapping descriptions will be omitted. First, with reference toFIGS. 1 to 4, a reactor10according to an embodiment will be described.

Note that, the axial direction in the following description represents a direction along a center axis A of a core12of the reactor10. Further, the radial direction represents a direction of radius of a circle centered about the axis A, and the circumferential direction represents the circumferential direction of the circle. Further, for the sake of convenience, the direction indicated by an arrow B in the drawings is referred to as the axially upward direction.

The reactor10is e.g. an alternating-current (AC) reactor, and includes the core12, coils14, a terminal block16, an attachment flange18, and a cover20. The core12is configured by laminating a plurality of magnetic steel sheets in the axial direction.

The core12may be made of a magnetic material, such as ferrite, powder magnetic core, or amorphous. The core12is tubular, and includes a plurality of core segments22,24, and26arranged so as to align in the circumferential direction.

The core segments22,24, and26have the same shape. Specifically, as shown inFIG. 3, the core segment22includes a back yoke segment28and a tooth30projecting radially inside from the back yoke segment28.

Similarly, the core segment24includes a back yoke segment34and tooth36projecting radially inside from the back yoke segment34. Similarly, the core segment26includes a back yoke segment40and a tooth42projecting radially inside from the back yoke segment40.

The back yoke segments28,34, and40aligning in the circumferential direction constitute a tubular back yoke46. The back yoke46has a hexagonal outer shape, and is centered about the axis A.

Note that, the outer shape of the back yoke46is not limited to the hexagonal shape, but may be a circular or polygonal shape. A total of three rod receiving holes32are formed at the back yoke46(at each of the back yoke segments28,34, and40in this embodiment).

The teeth30,36, and42are arranged in the circumferential direction at substantially equal intervals (i.e., 120°). The back yoke46and the teeth30,36, and42define an internal space S1of the core12. The coils14are wound around the respective teeth30,36, and42. Thus, the coils14are installed inside of the core12.

The terminal block16is attached to an axially upper end48(first end) of the core12. The terminal block16includes a base50and a plurality of terminals52fixed to the axially upper side of the base50.

The base50has a hexagonal outer shape substantially the same as the back yoke46. The base50is formed with a plurality of communication holes54extending through the base50in the axial direction. The internal space S1of the core12and the outside of the reactor10are in fluid communication with each other through the respective communication holes54. Each terminal52is a conductor, and lead wires (not shown) of the coils14are connected to the respective terminals52.

As shown inFIG. 4, the attachment flange18is a flat plate member separated from the core12, and is formed with a through-hole56at its center part. The through-hole56is a tripod (tri-star) shaped hole, and includes a first hole56a,a second hole56b,and a third hole56cextending radially outside from the axis A.

The first hole56a,the second hole56b,and the third hole56care respectively disposed at circumferential positions corresponding to teeth30,36, and42(i.e., at intervals of 120°).

The first hole56areceives therein the axially upper-side coil end of the coil14wound around the tooth30. The second hole56breceives therein the axially upper-side coil end of the coil14wound around the tooth36. Further, the third hole56creceives therein the axially upper-side coil end of the coil14wound around the tooth42.

The attachment flange18is formed with a total of three rod receiving holes58. Note that, only two of the three rod receiving holes58are shown inFIG. 4. The rod receiving holes58are respectively in communication with the rod receiving holes32formed at the back yoke46of the core12.

The attachment flange18has an axially upper end face60and an axially lower end face62opposite the end face60. The end faces60and62are parallel to each other, and arranged to be perpendicular to the axis A. Further, a plurality of mounting holes64are formed at the attachment flange18.

The attachment flange18is held between the terminal block16and the core12so as to extend radially outside of the core12. Thus, the attachment flange18is disposed at a position between an axially lower end65(second end) of the core12and the terminals52. More specifically, the attachment flange18is spaced axially downward away from the terminals52, and is disposed between the terminals52and the axially upper end48of the core12.

The cover20is attached to the axially lower end65of the core12so as to cover the internal space S1of the core12from the axially lower side. The cover20includes a base66, a peripheral wall68, a bottom wall70, and a center wall72.

The base66is an annular flat plate member having a hexagonal outer shape substantially the same as the back yoke46of the core12, and arranged so as to be in surface-contact with the axially lower end65of the core12. A total of three rod receiving holes74(FIG. 4) are formed at the base66.

Note that, only two of the three rod receiving holes74are shown inFIG. 4. The rod receiving holes74are respectively in communication with the rod receiving holes32formed at the back yoke46of the core12.

The peripheral wall68extends axially downward from the base66, and extends along the wall surface defining the through-hole56formed at the attachment flange18so as to surround the axis A. The peripheral wall68is formed with communication holes68aextending through the peripheral wall68.

The bottom wall70is an annular flat plate member arranged to be parallel to the base66, and is connected to the axially lower end of the peripheral wall68. The bottom wall70extends so as to surround the axis A. The center wall72extends axially upward from a radially inner edge of the bottom wall70.

The axially upper end face of the center wall72faces the axially lower end faces of the teeth30,36, and42. The center wall72is formed with communication holes72aextending through the center wall72.

The peripheral wall68, the bottom wall70, and the center wall72define an annular recess76which is in fluid communication with the internal space S1of the core1. The annular recess76receives therein the axially lower coil ends of the coils14wound around the teeth30,36, and42.

The recess76(i.e., the internal space S1of the core12) defined in the cover20and the outside of the reactor10are in fluid communication with each other through the communication holes68aformed at the peripheral wall68and the communication holes72aformed at the center wall72.

As shown inFIG. 4, the reactor10further includes a total of three rods78. Each rod78is inserted into the rod receiving holes58,32, and74which are in communication with each other.

The axially top ends of the rods78are fixed to the attachment flange18, while the axially bottom ends of the rods78are fixed to the base66of the cover20. Further, the terminal block16is fixed to the attachment flange18by fastening tools, such as bolts. In this way, the core12, the terminal block16, the attachment flange18, and the cover20are integrally fixed to each another.

Next, with reference toFIGS. 5 and 6, an amplifier device100according to an embodiment of the invention will be described. The amplifier device100includes a power cabinet102and a plurality of motor drive devices104.

The power cabinet102is hollow, and includes a bottom wall108, side walls110and112, a rear wall114, a top wall116, and a door118pivotally supported by the side wall110. The side walls110and112extend upward from both side edges of the bottom wall108so as to be opposite to each other.

The rear wall114extends upward from the rear edge of the bottom wall108, and extends between the side walls110and112. The top wall116is connected to the top ends of the side walls110and112and the top end of the rear wall114. The bottom wall108, the side walls110and112, the rear wall114, and the top wall116define an internal space S2of the power cabinet102.

The door118can open and close so as to open and close the internal space S2to and from the outside of the power cabinet102.

A suction hole120is formed at the side wall112so as to extend through the side wall112. A fan122is installed in the suction hole120. The fan122introduces the outside air from the outside of the power cabinet102into the internal space S2through the suction hole120, when the door118is closed. Due to this, the air pressure in the internal space S2of the power cabinet102gets slightly higher than the outside air pressure of the outside of the power cabinet102.

On the other hand, an exhaust hole124is formed at the side wall110so as to extend through the side wall110. The air introduced into the internal space S2by the fan122passes through the internal space S2, and then is discharged to the outside through the exhaust hole124. By the air passing through the internal space S2in this way, the components of the motor drive devices104disposed in the internal space S2can be cooled.

In this embodiment, each motor drive device104supplies electric power to a motor built in e.g. a machine tool, an industrial machine, or a robot. Each motor drive device104includes a reactor10and a servo amplifier105.

As shown inFIG. 6, each servo amplifier105includes a chassis126, a heatsink128attached to a rear end126aof the chassis126, and a heat-generating element (not shown), such as a power element.

The heatsink128includes heat radiation fins (not shown), and the heat-generating element of the servo amplifier105is attached to the heatsink128. As shown inFIG. 6, a through-hole114ais formed at the rear wall114of the power cabinet102. The heatsink128is exposed to the outside of the power cabinet102through the through-hole114a,thereby the heatsink128of the servo amplifier105is disposed outside of the power cabinet102.

A power source106is installed outside of the power cabinet102. The power source106is e.g. an AC voltage source configured to supply alternating-current voltage to the motor drive devices104.

The reactor10is installed between one servo amplifier105and the power source106. For example, the reactor10reduces the peak current of regenerative current that is output from the servo amplifier105.

Next, with reference toFIG. 6, an attachment structure of the reactor10to the power cabinet102will be described. A through-hole114bis formed at the rear wall114of the power cabinet102. The core12of the reactor10is inserted into the through-hole114b,so that the terminal block16(i.e., the terminals52) and the attachment flange18are located in the internal space S2of the power cabinet102.

On the other hand, the cover20and a major part of the core12including the end65are exposed to the outside of the power cabinet102. The end face60of the attachment flange18faces the internal space S2, while the end face62of the attachment flange18is in surface-contact with an inner surface114cof the rear wall114.

In this state, bolts (not shown) are inserted to the respective mounting holes64formed at the attachment flange18, and fastened to screw holes (not shown) formed at the rear wall114. In this way, the attachment flange18is fixed to the rear wall114, and thus, the reactor10is fixed to the rear wall114as shown inFIG. 6.

In the state shown inFIG. 6, the attachment flange18closes the through-hole114bof the rear wall114, and a major part of the core12and the coils14(FIGS. 3 and 4) is exposed to the outside of the power cabinet102.

As described above, the air pressure of the internal space S2of the power cabinet102is increased by the operation the fan122to be higher than the outside air pressure of the outside of the power cabinet102. Therefore, the air in the internal space S2flows into the internal space S1of the core12through the communication holes54formed in the terminal block16, and is discharged to the outside through the communication holes68aand72aformed in the cover20.

As described above, in this embodiment, the reactor10can be fixed to the rear wall114by the attachment flange18as shown inFIG. 6. Due to this configuration, at least a part of each coil14, which generates heat during the operation of the reactor10, can be disposed outside of the power cabinet102.

Thereby, since the amount of the heat generating elements located in the internal space S2can be reduced, it is possible to reduce the quantity of heat to be generated in the internal space S2during the operation of the amplifier device100. Further, since at least a part of the core12can be exposed to the outside of the power cabinet102, it is possible to cool the core12by the outside air.

Further, since the heat accumulated in the core12can be conducted to the rear wall114of the power cabinet102through the attachment flange18, it is possible to effectively remove heat from the core12. Further, the attachment flange18has a simpler structure, by which, the reactor10can be easily attached to the power cabinet102along with reducing the manufacturing cost.

Further, in this embodiment, the attachment flange18is disposed between the terminals52and the end48of the core12. Due to this configuration, a major part of the core12and the coils14can be exposed to the outside of the power cabinet102. Accordingly, it is possible to more-effectively reduce the quantity of heat to be generated in the internal space S2during the operation of the amplifier device100, along with more-effectively cooling the core12by the outside air.

Further, in this embodiment, an airflow, which flows into the internal space S1of the core12through the communication holes54and then is discharged to the outside through the communication holes68aand72aof the cover20, is generated when the air pressure in the internal space S2is higher than the outside air pressure by the operation of the fan122.

Due to this configuration, it is possible to effectively cool the core12and the coils14by the airflow passing through the internal space S1. Thus, the core12and the coils14can be effectively cooled from both inside and outside of the core12. Further, it is possible to prevent foreign substances, such as cutting fluid, located outside of the power cabinet102from entering the internal space S1of the core12through the communication holes68aand72aand from being brought into contact with the coils14. Thus, the coils14can be prevented from deteriorating due to such foreign substances.

Next, with reference toFIGS. 7 and 8, a reactor130according to another embodiment will be described.FIG. 7is a view of the reactor130when seen from the axially lower side (i.e., the lower side inFIGS. 1 and 2).

The reactor130is different from the above-mentioned reactor10in the configuration wherein the reactor130further includes a seal132. The seal132is provided on the axially lower end face62of the attachment flange18so as to surround the core12. The seal132is comprised of e.g. an adhesive agent or an adhesive tape.

When the reactor130is fixed to the rear wall114as shown inFIG. 8, the seal132is interposed between the rear wall114and the attachment flange18so as to hermetically seal the through-hole114bof the rear wall114. As seen above, the core12of the reactor130has a tubular shape, by which, a hermetically sealing by the seal132can be easily implemented. Thereby, it is possible to reliably prevent foreign substances located outside of the power cabinet102from entering the internal space S2through the through-hole114b.

Next, with reference toFIG. 9, a reactor140according to still another embodiment will be described. The reactor140is different from the reactor10in the configuration wherein the reactor140includes a sealing section142in place of the cover20.

The sealing section142is attached to the axially lower end65of the core12so as to cover the internal space S1of the core12from the axially lower side to hermetically seal the internal space S1from the outside.

Due to this configuration, it is reliably prevent foreign substances located outside of the power cabinet102from entering the internal space S1.

Next, with reference toFIG. 10, a reactor150according to still another embodiment will be described. The reactor150is different from the reactor10in the configuration wherein the reactor150further includes handles152and154.

The handles152and154are fixed to the axially upper end face60of the attachment flange18so as to project axially upward from the end face60. The handles152and154may be fixed to the end face60by e.g. an adhesive agent, welding, or screw clamp. In this embodiment, the handle152and the handle154are fixed to the end face60so that the terminal block16is disposed therebetween.

A user grasps the handles152and154when moving the reactor150. The user can easily lift and move the reactor150using the handles152and154.

Next, with reference toFIG. 11, a reactor160according to still another embodiment will be described. The reactor160is different from the reactor10in the configuration of the attachment flange18′. Specifically, the attachment flange18′ according to this embodiment is provided with a plurality of bosses162.

The bosses162are formed integrally with the axially upper end face60of the attachment flange18′ so as to project axially upward from the end face60. A screw hole162ais formed at each boss162. Eyebolts (not shown) can be fastened to the respective screw holes162a.Thus, each screw hole162afunctions as a fastening section for fastening the eyebolt.

When lifting up the reactor160by a lifting machine, the eyebolts fastened to the screw holes162aare engaged with hooks of the lifting machine. By the eyebolts, it is possible to lift up and transport the reactor160by the lifting machine even when the reactor160is heavy in weight.

Note that, in the above-mentioned embodiments, the attachment flange18,18′ is disposed between the terminal block16and the core12. However, the attachment flange may be disposed between the end48and the end65of the core12.

As an example, the attachment flange includes a through-hole at its center, wherein the through-hole has an outer shape substantially the same as the core12(i.e., hexagonal shape in the embodiment shown inFIG. 1). In this case, the attachment flange may be fixed to the outer peripheral surface of the core12by e.g. welding or bonding, in a condition where the core12is inserted into the through-hole.

Thereby, the attachment flange is fixed to the outer peripheral surface of the core12at a position between the end48and the end65, so as to extend radially outside from the outer peripheral surface of the core12and extend over the entire circumference of the core12to surround it.

In this case, the attachment flange may be disposed at a position between the first end48and the second end65to be closer to the first end48than the second end65. According to this configuration, a major part of the core12and the coils14can be exposed to the outside of the power cabinet102.

Further, in the above-mentioned, the attachment flange18,18′ is a member separate from the core12, which is attached to the core12. However, the attachment flange18,18′ may be formed integrally with the core12or the terminal block16.

Further, in the above-mentioned embodiments, the attachment flange18,18′ is disposed in the internal space S2of the power cabinet102. However, the attachment flange18,18′ may be disposed outside of the power cabinet102. In this case, the attachment flange18,18′ is fixed to the outer surface of the rear wall114so that the end face60of the attachment flange18,18′ is in surface-contact with the outer surface of the rear wall114.

Further, the attachment flange18,18′ may be disposed at any position in the axial direction of the core12. Further, the back yoke46of the core12may have a cylindrical shape or any tubular outer shape.

Although the invention has been described above through various embodiments, the embodiments do not limit the inventions according to the claims. Further, a configuration obtained by combining the features described in the embodiments of the invention can be included in the technical scope of the invention. However, all combinations of these features are not necessarily essential for solving means of the invention. Furthermore, it is obvious for a person skilled in the art that various modifications or improvements can be applied to the embodiments.