KR102651506B1 - Field magnet unit having cooling function - Google Patents

Abstract

The present invention relates to a field unit with a cooling function configured to reduce heat accumulation by providing a refrigerant circulation structure. A field unit with a cooling function according to the present invention includes a housing 10 and a coil member 20 coupled to the housing 10. The housing 10 is provided with a ring member 11, and first and second duct members 14 and 15, as well as covers 12 and 13, are provided on the upper and lower sides of the ring member 11, respectively. The housing 10 constitutes a magnetic path for the coil member 20. The first and second duct members 14 and 15 are provided with a plurality of first and second cut grooves 142 and 152, respectively, from the outer periphery toward the inside, and the ring member 11 has these cut grooves 142, Grooves 111 and 112 are formed at positions corresponding to 152). The first and second cut grooves 142 and 152 pass through the upper and lower surfaces of the coil member 20, respectively, and then communicate with each other inside the housing 10. The first and second cut grooves 142 and 152 form passages for circulation of refrigerant.

Description

Field unit with cooling function {FIELD MAGNET UNIT HAVING COOLING FUNCTION}

The present invention relates to a field unit applicable to a power conversion device, and particularly to a field unit with a cooling function configured to reduce heat accumulation by providing a refrigerant circulation structure.

Generally, a field or field unit refers to a magnetic device that generates a magnetic field in an electrical device such as a motor or generator. Typically, magnetic devices are configured such that a coil is wound around a bobbin made of ferrite. As another example of implementing a field unit, one in which a coil is stored inside a cylindrical housing has been proposed. For example, Republic of Korea Patent No. 10-1735860 (title: electromagnet and electromagnetic coil assembly) discloses an electromagnet composed of a flat plate shape. The electromagnet or electromagnetic coil assembly disclosed herein has a structure in which an annular groove is formed in a pole piece made of a magnetizable material, a coil assembly is mounted there, and an armature plate is installed on the upper side.

An example of application of a field unit is a non-rotating power conversion device. Figure 1 is a schematic diagram showing an example of a non-rotating power conversion device. In the drawing, the power conversion device 100 is composed of a field unit 100A and an armature unit 100B in a stacked form. Regarding the power conversion device 100 having this structure, Republic of Korea Patent No. 10-2332747 (name: non-rotating direct current generator), published patent No. 10-2021-0150835 (name: non-rotating alternating current generator), and published patent It is disclosed in No. 10-2021-0161811 (name: Power conversion device).

Generally, a field unit includes a coil member around which a conductive line is wound. The coil member is driven by alternating current or direct current, and is suitably driven by switching. In some applications the coil member is driven at high frequency. Coil members basically generate heat by resistance loss or eddy current. In particular, when the frequency of the field current or the driving frequency of the coil member increases, heat generation increases dramatically due to an increase in the skin effect and proximity effect. Heat generated from the coil member may accumulate in the coil member. In particular, in the case of a coil member stored inside a housing, excessive heat accumulation may occur. Heat accumulation in the coil member results in an increase in temperature of the conductors constituting the coil member. Additionally, an increase in the temperature of the conductor leads to an increase in its resistance value, further increasing heat generation in the coil member. This inappropriate chain effect not only reduces the magnetic field generation efficiency of the field unit, but can also cause a short circuit in the coil member or a fire.

The present invention was created in consideration of the above circumstances, and its technical purpose is to provide a field unit configured to have a cooling function and prevent excessive heat accumulation in the coil member.

A field unit with a cooling function according to the first aspect of the present invention for realizing the above object is a field unit that generates a magnetic field when a field current is supplied, comprising a housing provided with a hollow portion in the center and coated with an insulating material. It is configured by winding a conductor, has a terminal for supplying field current, and includes a coil member coupled to the housing. The housing has a hollow ring shape, and first and second electrodes are provided on the upper and lower sides. 2 A ring member provided with first and second grooves at positions corresponding to the incision grooves, on the inside of which the coil member is seated, and disposed on one side of the ring member, having a disk shape and a hollow portion in the central portion. A first duct member is formed with a through hole for forming a first duct member and is provided with two or more first cut grooves in an inner direction from the outer periphery, and is disposed on the other side of the ring member, has a disk shape, and has a hollow portion in the central portion. A second duct member is provided with a through hole for forming the structure and is provided with two or more second cut grooves in an inner direction from the outer periphery, and the upper central portion of the first duct member is integrated with the first duct member. It is formed in a square shape, and is provided with a support part that supports the inner peripheral surface of the coil member and the second duct member, and the first cut groove and the second cut groove communicate with each other through the support part.

In addition, covers are provided on the outside of the first and second duct members, respectively.

Additionally, the first and second duct members are press-fitted into the ring member.

Additionally, the cover is press-fitted into the ring member.

In addition, the inner peripheral surface of the ring member is characterized in that a stepped portion for supporting the first and second duct members is provided.

Additionally, the first and second duct members are characterized in that they are coated with an insulating material.

In addition, the housing is characterized in that it is made of a material that can be magnetized.

In addition, the diameter of the outer circumference of the support part is set to a size corresponding to the diameter of the inner circumference of the coil member, and a third cut groove is provided from the outer circumference to the inner circumference, and the first and second cut grooves are the first and second cut grooves. 3 It is characterized by mutual communication through incision grooves.

In addition, the diameter of the outer circumference of the support part is set to a size corresponding to the diameter of the inner circumference of the coil member, and a third groove is provided along a concentric circle on the upper side, and the first and second cut grooves are the third groove. It is characterized by mutual communication through.

In addition, at least one of the first and second cut grooves is characterized in that it is employed as a guide groove that guides the terminal of the coil member to the outside of the housing.

In addition, the conductive wire constituting the coil member is characterized in that the cross-section is square or has a longitudinal shape.

In addition, the inner peripheral surface of the ring member is characterized in that a guide groove is provided for guiding the outer terminal of the coil member in an upward or downward direction.

Additionally, tubes for circulation of refrigerant are installed in the first and second cut grooves.

A field unit with a cooling function according to the second aspect of the present invention is a field unit that generates a magnetic field when a field current is supplied, and is composed of a housing having a hollow portion in the center, and a conductor coated with an insulating material wound, In addition, it is provided with a terminal for supplying field current, and is configured to include a coil member coupled to the housing, wherein the housing is made of a hollow ring shape and has first and second cut grooves corresponding to the upper and lower sides. A ring member is provided with a groove at the position, on which the coil member is seated, and is disposed on one side of the ring member, has a disk shape, and has a through hole formed in the center to form a hollow portion, and an inner portion from the outer periphery. A first cover provided with two or more first flow grooves in each direction, disposed on the other side of the ring member, has a disk shape, and has a through hole formed in the center to form a hollow portion, and is directed inward from the outer periphery. It is composed of a second cover provided with two or more second flow grooves, and is formed integrally with the second cover in the upper central portion of the second cover, and connects the inner peripheral surface of the coil member and the first cover. A supporting part is provided to support it, and the first flow groove and the second flow groove communicate with each other through the support part.

According to the present invention having the above-described configuration, the housing is made of a material that can be magnetized, and the coil member is installed in close contact with the housing. Accordingly, the magnetic field generated by the coil member can be projected with high efficiency to other adjacent devices through the housing.

Additionally, a plurality of ducts are provided in the housing while entirely surrounding the outer surface of the coil member. When heat is generated from the coil member, the temperature of the housing and its interior rises due to heat conduction and heat radiation, and thus a flow of air occurs between the inside and outside of the housing. Convection of air occurs through the ducts described above. Additionally, heat energy inside the housing is released to the outside due to the flow of air through the duct, thereby preventing excessive heat energy from accumulating in the housing and coil member.

The attached drawings are for explaining embodiments of the present invention. Therefore, for efficient description of the embodiment, it should be understood that some components may be exaggeratedly described or omitted.
Figure 1 is a configuration diagram schematically showing an example of a power conversion device 100 including a field unit 100A and an armature unit 100B.
Figure 2 is a perspective view showing the external shape of a field unit 1 with a cooling function according to an embodiment of the present invention.
Figure 3 is an exploded perspective view of the field unit 1 shown in Figure 2.
Figure 4 is a perspective view showing another configuration example of the cover 50 coupled to the upper side of the housing 10.
Figure 5 is a cross-sectional view showing the cross-sectional configuration along line A-A' in Figure 2.
FIG. 6 is a perspective view and a plan view showing another example of the configuration of the first duct member 14 in FIG. 3.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. However, the embodiments described below illustratively show one preferred embodiment of the present invention, and the examples of these embodiments are not intended to limit the scope of the present invention. Those skilled in the art will easily understand that the present invention can be implemented with various modifications without departing from its technical spirit.

Figure 2 is a perspective view showing a field unit 1 with a cooling function according to an embodiment of the present invention. In the drawing, the field unit 1 includes a housing 10. Inside the housing 10, a coil member 20 (FIG. 3) is provided to generate a magnetic field. The housing 10 includes a ring member 11 and covers 12 and 13 coupled to the upper and lower sides of the ring member 11.

A hollow portion 10a is provided in the central portion of the housing 10. Although not specifically shown in the drawing, a cylindrical core member is inserted into the hollow portion 10a. The field unit 1 is installed and coupled to the core member together with the armature unit. The coupling structure of the field unit and the armature unit to the core member is disclosed in Korean Patent No. 10-2332747 (name: Non-rotating direct current generator).

In addition, a plurality of grooves 111 and 112 are provided along the edges of the upper and lower sides of the housing 10, more specifically, the upper and lower sides of the ring member 11, respectively. These grooves 111 and 112 are for circulation of refrigerant, such as air, between the outside and inside of the housing 10. And at least one of the grooves 111 and 112 functions as an extraction groove for drawing the terminals 20a and 20b of the coil member 20 to the outside of the housing 10. Inside the housing 10, a duct is provided for circulation of refrigerant while communicating with the grooves 111 and 112. The duct is preferably configured to pass through the upper, inner, and lower surfaces of the coil member 20.

FIG. 3 is an exploded perspective view of the field unit 1 shown in FIG. 2. In the drawing, as described above, the field unit 1 has a housing 10 and a coil member 20, and the housing 10 has a ring member 11 and upper and lower covers 12 and 13. . The coil member 20 generates a magnetic field by a field current supplied externally through the terminals 20a and 20b, and the housing 10 stably supports and houses the coil member 20 and also stores the coil member 20. It is to construct a magnetic path for the magnetic field generated in . Furthermore, the housing 10 is provided with first and second duct members 14 and 15. These are intended to form a duct for circulation of the refrigerant inside the housing 10 and to minimize magnetic flux loss due to the space by eliminating the space between the coil member 20 and the housing 10.

The coil member 20 is composed of a coiled wire coated with an insulating material such as enamel. In addition, preferably, the outside of the coil member 20 may be coated with an insulating film that entirely surrounds the coil member 20 for more reliable insulation between the coil member 20 and the housing 10. The coil member 20 is provided with terminals 20a and 20b for supplying field current. Here, one terminal 20a is connected to the inner peripheral side of the coil member 20, and the other terminal 20b is connected to the outer peripheral side of the coil member 20. As will be described later, these terminals (20a, 20b) are guided to the inner peripheral side of the ring member (11) through the cut grooves (142, 152) of the first and second duct members (14, 15) and then inserted into the groove ( It is drawn out to the outside of the housing 10 through 111 and 112). Hereinafter, the terminal 20a connected to the inner peripheral side of the coil member 20 will be referred to as an inner terminal, and the terminal 20b connected to the outer peripheral side of the coil member 20 will be referred to as an outer terminal.

Additionally, in a preferred embodiment of the present invention, the coil member 20 is composed of a conductor having a square or rectangular cross-section. A conductor with a square or rectangular cross-section has a larger surface area than a circular conductor with a diameter equal to its width, so it can provide the effect of reducing heat generation due to an increase in the skin effect.

The ring member 11 has a ring shape with a hollow interior, and a plurality of grooves 111 and 112 are provided at the upper and lower portions along the edge as described above. The ring member 11 is preferably made of a magnetizable material and is suitably heat treated. The diameter of the inner peripheral surface of the ring member 11 is set to a size corresponding to the diameter of the outer peripheral surface of the coil member 20. The coil member 20 is disposed while being seated inside the ring member 11, and the inner peripheral surface of the ring member 11 supports the outer peripheral surface of the coil member 20. Step portions 113 and 114 are provided at the upper and lower ends of the ring member 11, respectively, along the inner peripheral surface. These stepped portions 113 and 114 are for supporting the first and second duct members 14 and 15. The length between the stepped portions 113 and 114 is preferably set to a size corresponding to the height of the coil member 20. Additionally, the stepped portions 113 and 114 may be removed as needed. In this case, the first and second duct members 14 and 15 are installed in close contact with the upper and lower sides of the coil member 20.

In addition, a guide groove 115 is preferably provided on the inner peripheral surface of the ring member 11 to guide the outer terminal 20b of the coil member 20 in an upward or downward direction. The guide groove 115 is disposed at a position corresponding to the predetermined grooves 111 and 112 of the ring member 11. Accordingly, the outer terminal 20b of the coil member 20 is guided upward or downward through the guide groove 115 and then guided to the outside of the housing 10 through the grooves 111 and 112. The guide groove 115 may be removed when the thickness of the conductive wire constituting the coil member 20 is below a certain level.

A first duct member 14 is provided on one side of the coil member 20 and below the coil member 20 in the drawing. The first duct member 14 is preferably made of a magnetizable material and is suitably heat treated. The first duct member 14 has a disk shape, and a support portion 160 for supporting the coil member 20 from the inside is provided at the upper central portion. The outer diameter of the first duct member 14 is set to a size corresponding to the inner diameter of the ring member 11. In a preferred embodiment, the first duct member 14 is installed while being pressed into the inner peripheral surface of the ring member 11. The first duct member 14 has a through hole 141 formed in the central portion to form the hollow portion 10a, and a plurality of cut grooves 142 are provided in the inner direction from the outer periphery. In this embodiment, the cutting groove 142 is radially installed in the first duct member 14.

The diameter of the outer peripheral surface of the support portion 160 is set to a size corresponding to the diameter of the inner peripheral surface of the coil member 20, and its height is set to a size corresponding to the thickness of the coil member 20. The support portion 160 supports the inner peripheral surface of the coil member 20 and also supports the second duct member 15, which will be described later. Additionally, the support portion 160 is provided with a plurality of cut grooves 161 in a vertical direction along the outer peripheral surface. The cutting grooves 161 are installed at corresponding positions so as to communicate with the cutting grooves 142. As will be described later, the cut groove 142 communicates with the cut groove 152 of the second duct member 15 through the cut groove 161. In addition, although not specifically shown in the drawings, the inner terminal 20a of the coil member 20 is guided upward or downward through the cut groove 161 and then inserted into the housing 10 through the cut grooves 142 and 152. ) is guided to the outside of the

A second duct member 15 is provided on the other side of the coil member 20, on top of the coil member 20 in the drawing. The second duct member 15 is preferably made of a magnetizable material and is suitably heat treated. The second duct member 15 has a disk shape, and its outer diameter is set to a size corresponding to the inner diameter of the ring member 11. In a preferred embodiment, the second duct member 15 is installed while being pressed into the inner peripheral surface of the ring member 11. The second duct member 15 has a through hole 151 formed in the central portion to form the hollow portion 10a, and a plurality of cut grooves 152 are provided in the inner direction from the outer periphery. Preferably, the cutting groove 152 is installed radially in the second duct member 15. The cutting groove 152 is installed at a position corresponding to the cutting groove 142, and the cutting groove 161 of the support portion 160 are communicated with each other through

In the present invention, the size and shape of the cut grooves 142 and 152 provided in the first and second duct members 14 and 15 are not specified. Additionally, the shapes and sizes of the cut grooves 142 and 152 provided in the first duct member 14 and the second duct member 15 may be configured differently. Additionally, in a preferred embodiment of the present invention, the first and second duct members 14 and 15 are entirely covered with an insulating material such as Teflon for more reliable insulation from the coil member 20.

Covers 12 and 13 are installed outside the first and second duct members 14 and 15. Covers 12 and 13 can be removed as needed. The covers 12 and 13 have substantially the same configuration. The covers 12 and 13 are preferably made of a magnetizable material and are appropriately heat treated. The covers 12 and 13 have a disk shape, and through holes 121 and 131 are provided in the central portion to form the hollow portion 10a. Additionally, in a preferred embodiment, the covers 12 and 13 are entirely covered with an insulating material such as Teflon for more reliable insulation. The outer diameter of the covers 12 and 13 is formed to have a size corresponding to the inner diameter of the ring member 11. Preferably, the covers 12 and 13 are press-fitted into the inside of the ring member 11.

Additionally, in another embodiment of the present invention, the cover 12 and the second duct member 15 are integrated. Figure 4 is a perspective view showing another configuration example of the housing 10, that is, the cover 50 coupled to the upper side of the ring member 11. In the drawing, the cover 50 is made of a magnetizable material and is appropriately heat treated. In addition, preferably, the cover 50 is entirely covered with an insulating material, such as Teflon. A through hole 51 for forming a hollow portion 10a is provided in the central portion of the cover 50, and a flow groove for the flow of refrigerant such as air is provided on the inner side, that is, the side opposite to the coil member 20. (52) Many are provided. The flow groove 52 is formed radially inward from the outer periphery of the cover 52. The number, size, and shape of the flow grooves 52 are not specified. However, the length of the flow groove 52 is set to a size that can communicate with the cut groove 161 of the support portion 160. Additionally, the outer diameter of the cover 50 is set to a size corresponding to the inner diameter of the ring member 11, and the cover 50 is preferably press-fitted into the ring member 11.

Additionally, although not specifically shown in the drawings, the cover 13 and the first duct member 14 may also be integrated. In this case, the lower cover will have a support portion in the central portion and, like the upper cover 50, will be provided with a plurality of flow grooves radially from the outer periphery to the inner direction.

FIG. 5 is a cross-sectional view showing the cross-sectional configuration along line A-A' in FIG. 2. In the drawing, the coil member 20 is disposed in close contact with the upper side of the first duct member 14, and the first duct member 15 is disposed in close contact with the upper side of the coil member 20. Additionally, the first and second duct members 14 and 15 and the coil member 20 are disposed in close contact with the inner peripheral surface of the ring member 11. Additionally, covers 12 and 13 are disposed in close contact with the outer surfaces of the duct members 14 and 15, respectively. The ring member 11, the duct members 14 and 15, and the covers 12 and 13 constitute the housing 10. Accordingly, the coil member 20 is mounted in close contact with the housing 10. As described above, all components constituting the housing 10 are made of a material that can be magnetically rotated, and provide a magnetic path for projecting the magnetic field generated in the coil member 20. Accordingly, the magnetic field generated by the coil member 20 can be efficiently provided to other adjacent devices, such as an armature unit.

In particular, the housing 10 has grooves 111 and 112 provided on the upper and lower sides of the ring member 11 that correspond to the cut groove 152 of the second duct member 15 and the cut groove of the first duct member 14. It is communicated through (142, 161). These communication structures constitute a passage for refrigerant circulation, that is, a duct for refrigerant, for the circulation of refrigerant such as air. The duct for the refrigerant is formed while passing through the upper surface, inner peripheral surface, and lower surface of the coil member 20. That is, the refrigerant duct is configured to allow the refrigerant to flow while entirely surrounding the outer surface of the coil member 20. When the coil member 20 is driven, a large amount of heat is generated from the coil member 20. When heat is generated in the coil member 20, the temperature of the housing 10 and its interior increases due to heat conduction and heat radiation. When the air temperature inside the housing 10 increases, a difference in air density occurs between the inside and outside of the housing 10, and the density difference causes the flow of air, that is, convection, between the inside and outside of the housing 10. It happens. At this time, the flow amount and speed of air are proportional to the difference in air density between the inside and outside of the housing 10. In other words, as the temperature inside the housing 10 increases, the flow amount and flow speed of air increase proportionally. Convection of air occurs through a duct for the refrigerant, as shown by the dotted line in the drawing. In addition, heat energy inside the housing 10 is released to the outside by the flow of refrigerant, that is, air, thereby preventing excessive heat energy from accumulating in the housing 10 and the coil member 20.

Above, embodiments according to the present invention have been described. However, the present invention is not limited to the above embodiments. The present invention can be implemented with various modifications without departing from its technical spirit.

For example, in the above-described embodiment, a tube for circulation of refrigerant may be installed in the communication structure formed between the grooves 111 and 112 of the ring member 11.

Additionally, the shape and structure of the first duct member 14 are not specified. FIG. 6 is a perspective view and a plan view showing another example of the configuration of the first duct member 14 shown in FIG. 3. In FIG. 6 , the first duct member 60 has a disk shape similar to the configuration of FIG. 3 and is provided with a support portion 63 at the upper central portion for supporting the coil member 20 from the inside. Additionally, a through hole 61 is formed in the central portion to form the hollow portion 10a, and a plurality of cut grooves 62 are provided in the inner direction from the outer periphery. Meanwhile, in this configuration example, a groove 631 is formed along a concentric circle on the upper side of the support portion 63, and the cut groove 62 extends inside the groove 631, so that the groove 631 and the cut groove 62 communicate with each other. do. In this configuration, the coil member 20 is disposed in close contact with the outer peripheral surface of the support portion 63, and the cut grooves 62 and 152 of the first and second duct members 60 and 15 are aligned with the groove 631 of the support portion 63. ) communicate with each other. And the other configuration is substantially the same as the embodiment of FIG. 3.

In addition, in the configuration of FIG. 6 , the first duct member 60 and the cover 13 may be formed integrally, as in the above-described embodiment.

1: field unit, 10: housing,
10a: hollow part, 11: ring member,
12, 13: cover, 14, 15: duct member,
20: coil member, 20a, 20b: terminal.
111, 112: Home.

Claims (14)

In the field unit that generates a magnetic field when field current is supplied,
A housing having a hollow portion in the central portion,
It is constructed by winding a conductor coated with an insulating material, has a terminal for supplying field current, and includes a coil member coupled to the housing,
The housing has a hollow ring shape, has first and second grooves on the upper and lower sides at positions corresponding to the first and second cut grooves, and includes a ring member on the inside of which the coil member is seated;
A first duct member disposed on one side of the ring member, having a disk shape, a through hole formed in the central portion to form a hollow portion, and provided with two or more first cut grooves in the inner direction from the outer periphery, and
A second duct member is disposed on the other side of the ring member, has a disk shape, has a through hole formed in the central portion to form a hollow portion, and is provided with two or more second cut grooves in the inner direction from the outer periphery. It is composed of
A support portion is provided at the upper central portion of the first duct member, is formed integrally with the first duct member, and supports the inner peripheral surface of the coil member and the second duct member,
A field unit with a cooling function, wherein the first cut groove and the second cut groove communicate with each other through the support part. According to paragraph 1,
A field unit with a cooling function, characterized in that covers are provided on the outside of the first and second duct members, respectively. According to paragraph 1,
A field unit with a cooling function, wherein the first and second duct members are press-fitted into the ring member. In paragraph 2
A field unit with a cooling function, wherein the cover is press-fitted into the ring member. According to paragraph 1,
A field unit with a cooling function, characterized in that a stepped portion for supporting the first and second duct members is provided on the inner peripheral surface of the ring member. According to paragraph 1,
A field unit with a cooling function, wherein the first and second duct members are covered with an insulating material. According to paragraph 1,
A field unit with a cooling function, wherein the housing is made of a material that can be magnetized. According to paragraph 1,
The diameter of the outer circumference of the support part is set to a size corresponding to the diameter of the inner circumferential surface of the coil member, and a third cut groove is provided from the outer circumference to the inner circumference, and the first and second cut grooves are the third cut grooves. A field unit with a cooling function characterized by mutual communication through grooves. According to paragraph 1,
The diameter of the outer circumference of the support part is set to a size corresponding to the diameter of the inner circumference of the coil member, and a third groove is provided along a concentric circle on the upper side, and the first and second cut grooves are formed through the third groove. A field unit with a cooling function characterized by mutual communication. According to paragraph 1,
A field unit with a cooling function, wherein at least one of the first and second cut grooves is employed as a guide groove that guides the terminal of the coil member to the outside of the housing. According to paragraph 1,
A field unit with a cooling function, wherein the conductors constituting the coil member have a square or long cross-section. According to paragraph 1,
A field unit with a cooling function, characterized in that a guide groove is provided on the inner peripheral surface of the ring member to guide the outer terminal of the coil member in an upward or downward direction. According to paragraph 1,
A field unit with a cooling function, characterized in that tubes for circulation of refrigerant are installed in the first and second cut grooves. In the field unit that generates a magnetic field when field current is supplied,
A housing having a hollow portion in the central portion,
It is constructed by winding a conductor coated with an insulating material, has a terminal for supplying field current, and includes a coil member coupled to the housing,
The housing has a hollow ring shape, has grooves on the upper and lower sides at positions corresponding to the first and second cut grooves, and includes a ring member on the inside of which the coil member is seated,
A first cover disposed on one side of the ring member, having a disk shape, a through hole formed in the central portion to form a hollow portion, and provided with two or more first flow grooves in the inner direction from the outer periphery, and
A second cover is disposed on the other side of the ring member, has a disk shape, has a through hole formed in the center to form a hollow portion, and is provided with two or more second flow grooves in the inner direction from the outer periphery. It is composed,
The upper central portion of the second cover is formed integrally with the second cover and is provided with a support portion that supports the inner peripheral surface of the coil member and the first cover,
A field unit with a cooling function, wherein the first flow groove and the second flow groove are communicated with each other through the support part.

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