High-voltage capacitor

Abstract

To provide a high-voltage capacitor which allows improvement in reliability.SOLUTION: A high-voltage capacitor 1 comprises: a pair of capacitors C; a common conductor 20 which is electrically connected to each of the pair of capacitors C; and a pair of individual conductors 30 each of which is electrically connected to the corresponding one of the capacitors C. The pair of capacitors C each has: an element assembly 10 which has a columnar shape with a first direction D1 as its axial direction, and which has a first lateral surface 10c and a second lateral surface 10d facing each other in a second direction D2 perpendicular to the first direction D1; a first electrode 11, disposed on the first lateral surface 10c, which is electrically connected to the corresponding one of the individual conductors 30; and a second electrode 12, disposed on the second lateral surface 10d, which is electrically connected to the common conductor 20. At the same time, the pair of capacitors C is disposed such that the first electrodes 11 face each other in the second direction D2. Viewing in the first direction D1, the common conductor 20 surrounds the pair of capacitors C and the pair of individual conductors 30.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to high-voltage capacitors.

Background Art

[0002] Known high-voltage through capacitors include a capacitor, a pair of individual conductors, and a common conductor (see, for example, Patent Document 1). The capacitor has a body in which a pair of through holes are formed, and a first electrode and a second electrode provided on both surfaces of the body where the through holes open. The first electrode is connected to an individual conductor inserted through the through hole. The second electrode is connected to the common conductor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One aspect of the present disclosure aims to provide a high-voltage capacitor with improved reliability.

Means for Solving the Problems

[0005] A high-voltage capacitor according to one aspect of the present disclosure comprises a pair of capacitors, a common conductor electrically connected to each of the pair of capacitors, and a pair of individual conductors electrically connected to the corresponding capacitors, wherein each pair of capacitors has a columnar shape with a first direction as its axial direction and a first side surface and a second side surface that are opposite to each other in a second direction perpendicular to the first direction, and each has a first electrode disposed on the first side and electrically connected to the corresponding individual conductor, and a second electrode disposed on the second side and electrically connected to the common conductor, wherein the first electrodes are arranged to face each other in the second direction, and when viewed from the first direction, the common conductor surrounds the pair of capacitors and the pair of individual conductors.

[0006] The inventors conducted research on high-voltage capacitors that improve reliability. As a result, the inventors newly discovered the following: The strength of the electric field formed between two conductors with different potentials affects the reliability of a high-voltage capacitor. Hereafter, the strength of the electric field formed between two conductors with different potentials may simply be referred to as the "interconductor electric field strength." High-voltage capacitors with a high interconductor electric field strength are prone to dielectric breakdown. Dielectric breakdown occurs, for example, due to discharge along the inner surface of the element defining the through-hole. Therefore, high-voltage capacitors employing a configuration that reduces the interconductor electric field strength are less prone to dielectric breakdown. In other words, high-voltage capacitors employing a configuration that reduces the interconductor electric field strength have improved reliability.

[0007] The inventors conducted research on a configuration that reduces the electric field strength between conductors. As a result, the inventors found that the electric field strength between conductors can be reduced by using a pair of capacitors, each having a columnar shape. With such a pair of capacitors, the degree of design freedom is increased, and the distance between two conductors with different potentials can be increased. That is, the distance between the first electrode and the common conductor can be increased, as can the distance between the second electrode and the individual conductors. world The strength decreases.

[0008] In one embodiment described above, each pair of individual conductors includes a first portion electrically connected to a first electrode and a second portion connected to the first portion via a bend, and the distance between the second portions in the second direction may be longer than the distance between the first portions in the second direction. In this case, the size of the high-voltage capacitor can be suppressed to increase in the second direction while using the pair of second portions as a pair of tab connectors with a defined spacing.

[0009] In one of the above embodiments, the length of the second portion may be longer than the length of the first portion in a third direction perpendicular to the first and second directions. In this case, a pair of second portions can be used as a pair of tab connectors with defined sizes.

[0010] In one of the above embodiments, the element and the common conductor may be spaced apart from each other in a third direction perpendicular to the first and second directions. In this case, it is easier to increase the distance between the first electrode and the common conductor.

[0011] A high-voltage capacitor according to one of the above embodiments may further include an insulating case housing a pair of capacitors, and a resin filling the inside of the insulating case and sealing the pair of capacitors. In this case, the occurrence of discharge between two conductors with different potentials can be suppressed. [Effects of the Invention]

[0012] One aspect of the present invention provides a high-voltage capacitor that improves reliability. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a perspective view of a high-voltage capacitor according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along the line II-II in Figure 1. [Figure 3] Figure 3 is a perspective view showing a pair of capacitors, a common conductor, and a pair of individual conductors. [Figure 4]Figure 4 is a cross-sectional view along the line IV-IV in Figure 3. [Figure 5] Figure 5 is a plan view showing a pair of capacitors, a common conductor, and a pair of individual conductors. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described in detail below with reference to the attached drawings. In this description, the same reference numerals will be used for the same element or element having the same function, and redundant explanations will be omitted.

[0015] The configuration of the high-voltage capacitor 1 according to this embodiment will be described with reference to Figures 1 to 5. Figure 1 is a perspective view of the high-voltage capacitor according to this embodiment. Figure 2 is a cross-sectional view along the line II-II in Figure 1. Figure 3 is a perspective view showing a pair of capacitors, a common conductor, and a pair of individual conductors. Figure 4 is a cross-sectional view along the line IV-IV in Figure 3. Figure 5 is a plan view showing a pair of capacitors, a common conductor, and a pair of individual conductors. The high-voltage capacitor 1 is connected to a microwave magnetron, for example, similar to a conventional high-voltage through-hole capacitor, to prevent unwanted radiation noise from the microwave magnetron.

[0016] As shown in Figures 1 to 5, the high-voltage capacitor 1 comprises a pair of capacitors C, a common conductor 20, a pair of individual conductors 30, an insulating case 40, and resin 50. Each capacitor C has a base body 10, a first electrode 11, and a second electrode 12.

[0017] The base body 10 has a columnar shape with the first direction D1 as its axial direction. In this embodiment, the base body 10 has a prismatic shape. It can also be said that the base body 10 has a rectangular parallelepiped shape. The base body 10 has a first end face 10a and a second end face 10b that face each other in the first direction D1, a first side face 10c and a second side face 10d that face each other in the second direction D2, and a pair of third side faces 10e that face each other in the third direction D3. The first direction D1, the second direction D2, and the third direction D3 intersect (in this case are orthogonal).

[0018] The first side surface 10c, the second side surface 10d, and the pair of third side surfaces 10e extend in the first direction D1 so as to connect the first end surface 10a and the second end surface 10b to each other. In this specification, the direction from the second end surface 10b toward the first end surface 10a is the upward direction, and the first end surface 10a is located above the second end surface 10b.

[0019] The length of the element body 10 in the first direction D1 is longer than the length of the element body 10 in the second direction D2 and longer than the length of the element body 10 in the third direction D3. The length of the element body 10 in the first direction D1 is 5 mm or more and 15 mm or less, and as an example, it is 11 mm. The length of the element body 10 in the second direction D2 is 3 mm or more and 10 mm or less, and as an example, it is 5 mm. The length of the element body 10 in the third direction D3 is 3 mm or more and 10 mm or less, and it is 4 mm.

[0020] The element body 10 is made of, for example, an insulating material. The element body 10 includes, for example, ceramics. The ceramics include, for example, BaTiО 3、 BaZrO 3、 CaTiO 3、 or MgTiO3. The element body 10 may include additives added to the ceramics. The additives include, for example, Si, Mg, Zr, Zn, Y, V, Al, or Mn.

[0021] The first electrode 11 is disposed on the first side surface 10c. The first electrode 11 covers the entire first side surface 10c. The first electrode 11 is electrically connected to the corresponding individual conductor 30. That is, the first electrode 11 of one capacitor C is electrically connected to one individual conductor 30. The first electrode 11 of the other capacitor C is electrically connected to the other individual conductor 30.

[0022] The second electrode 12 is positioned on the second side surface 10d. The second electrode 12 covers the entire second side surface 10d. The second electrode 12 is electrically connected to the common conductor 20. The first electrode 11 and the second electrode 12 face each other in the first direction D1. The element 10 is located between the first electrode 11 and the second electrode 12. Therefore, the first electrode 11 and the second electrode 12 face each other indirectly in the first direction D1, with the element 10 located between the first electrode 11 and the second electrode 12.

[0023] The first electrode 11 and the second electrode 12 include a conductive metal material. The conductive metal material includes, for example, Ag. The first electrode 11 and the second electrode 12 may also include a magnetic material together with the conductive metal material. The magnetic material is, for example, Fe, Co, Ni, Cu, or Sr, or a combination thereof. The first electrode 11 and the second electrode 12 are formed, for example, by baking a conductive paste applied to the first side surface 10c and the second side surface 10d. The conductive paste for forming the first electrode 11 and the second electrode 12 includes the conductive metal material described above.

[0024] The pair of capacitors C are spaced apart from each other in the second direction D2. The pair of capacitors C are arranged so that their first electrodes 11 face each other in the second direction D2. The pair of capacitors C have the same shape.

[0025] The common conductor 20 is electrically connected to each of the pair of capacitors C. The common conductor 20 is electrically connected to the second electrode 12. The common conductor 20 is a grounded grounding device. The common conductor 20 has a peripheral portion 21 and a central portion 22. The peripheral portion 21 surrounds the central portion 22. The central portion 22 is a thick-walled portion, and the peripheral portion 21 is a thin-walled portion. The central portion 22 and the peripheral portion 21 are formed such that their center positions in the thickness direction (first direction D1) coincide. The central portion 22 protrudes from the peripheral portion 21 on both sides in the first direction D1.

[0026] An opening 23 is formed in the central portion 22. The opening 23 penetrates the central portion 22 in the first direction D1. In this embodiment, the opening 23 is located in the central region of the central portion 22 when viewed from the first direction D1. The opening 23 has a rectangular shape when viewed from the first direction D1, with the second direction D2 as the longer side. The common conductor 20 has a rectangular shape when viewed from the first direction D1, with the second direction D2 as the longer side. The rectangular shape includes shapes with rounded corners and shapes with rounded corners. The common conductor 20 may have a shape other than rectangular.

[0027] The common conductor 20 can also be described as having a rectangular frame shape with the second direction D2 as the longer side direction. The common conductor 20 includes a pair of sides 20a that face each other in the second direction D2, and a pair of sides 20b that face each other in the third direction D3. Side 20a is the shorter side. Side 20b is the longer side. Each side 20a, 20b has a peripheral part 21 and a central part 22, respectively. The common conductor 20 includes a conductive metallic material. The conductive metallic material includes, for example, Fe, Cu, or a Cu-Zn alloy.

[0028] The common conductor 20 surrounds a pair of capacitors C and a pair of individual conductors 30 when viewed from the first direction D1. Each capacitor C is inserted through the opening 23 such that its second electrode 12 is joined to the central portion 22 from the inside of the opening 23. The second electrode 12 of one capacitor C is joined to the central portion 22 of one side portion 20a. The second electrode 12 of the other capacitor C is joined to the central portion 22 of the other side portion 20a. The second electrodes 12 are joined to the central portion 22 by solder.

[0029] Each side portion 20b is spaced apart from the pair of capacitors C in a third direction D3. That is, the element 10 and the common conductor 20 are spaced apart from each other in a third direction D3. Each capacitor C is positioned at an equal distance from the pair of side portions 20b.

[0030] The length of the common conductor 20 in the second direction D2 is 20 mm or more and 50 mm or less, for example, 32 mm. The length of the common conductor 20 in the third direction D3 is 10 mm or more and 30 mm or less, for example, 20 mm. The thickness of the central part 22 (length in the first direction D1) is 4 mm for example. The thickness of the peripheral part 21 (length in the first direction D1) is 0.6 mm. The length of the opening 23 in the second direction D2 is 10 mm or more and 40 mm or less, for example, 18 mm, and the length of the opening 23 in the third direction D3 is 5 mm or more and 25 mm or less, for example, 15 mm. The distance between each side part 20b and the pair of capacitors C in the third direction D3 is 1.5 mm or more, for example, 5.5 mm.

[0031] Each of the pair of individual conductors 30 is electrically connected to the corresponding capacitor C. The pair of individual conductors 30 are inserted through the opening 23 together with the pair of capacitors C. The pair of individual conductors 30 are positioned between the pair of capacitors C and face each other in the second direction D2. The pair of individual conductors 30 have the same shape as each other. Each individual conductor 30 is electrically connected to the first electrode 11 of the corresponding capacitor C.

[0032] The individual conductor 30 has a first portion 31, a second portion 32, a third portion 33, a bent portion 34, and a bent portion 35. The first portion 31, the second portion 32, and the third portion 33 extend in a first direction D1. The bent portions 34 and 35 extend in a second direction D2. The first portion 31 is electrically connected to the first electrode 11. The first portion 31 is joined to the first electrode 11 by solder. The second portion 32 is connected to the upper end of the first portion 31 via the bent portion 34. The third portion 33 is connected to the lower end of the first portion 31 via the bent portion 35.

[0033] The distance L2 between the second parts 32 in the second direction D2 is longer than the distance L1 between the first parts 31 in the second direction D2. The distance L3 between the third parts 33 in the second direction D2 is longer than the distance L1. Distance L2 is greater than or equal to distance L3. Distances L2 and L3 are between 5 mm and 35 mm. The length of the individual conductor 30 in the first direction D1 is between 30 mm and 60 mm. The length of the first part 31 in the first direction D1 is longer than the length of the base body 10 in the first direction D1, for example, 22 mm. The length of the second part 32 in the first direction D1 is for example, 16 mm. The length of the third part 33 in the first direction D1 is for example, 12 mm. The length of the bent part 34 in the second direction D2 is greater than or equal to the length of the bent part 35 in the second direction D2.

[0034] In the third direction D3, the first portion 31, the third portion 33, the bent portion 34, and the bent portion 35 have the same length W1. In the third direction D3, the length W2 of the second portion 32 is longer than the length W1 of the first portion 31. That is, as viewed from the second direction D2, the second portion 32 is wider than the first portion 31. The second portion 32 functions as a tab connector. The individual conductors 30 are made of, for example, a conductive metallic material. The conductive metallic material includes, for example, Fe, Cu, or a Cu-Zn alloy.

[0035] The insulating case 40 has a hollow cylindrical shape with the first direction D1 as its axial direction. The insulating case 40 may have other shapes. The insulating case 40 houses a pair of capacitors C inside. In this embodiment, the insulating case 40 houses the entirety of each capacitor C, a part of the common conductor 20, and a part of each individual conductor 30 inside. The insulating case 40 is arranged to surround the pair of capacitors C and the pair of individual conductors 30. The peripheral portion 21 of the common conductor 20 is exposed from the insulating case 40. The peripheral portion 21 protrudes from the insulating case 40 around its entire circumference.

[0036] The insulating case 40 includes a first case 41 positioned above the common conductor 20 and a second case 42 positioned below the common conductor 20. The first case 41 encloses the upper part of the capacitor C, the upper part of the first section 31, the entire bent section 34, the lower end of the second section 32, and the upper part of the central section 22. The second case 42 encloses the lower part of the capacitor C, the lower part of the first section 31, the entire bent section 35, the upper end of the third section 33, and the lower part of the central section 22.

[0037] The first case 41 and the second case 42 are physically connected to the common conductor 20. The first case 41 is connected to the common conductor 20 such that the lower end surface of the inner surface of the first case 41 is in contact with the outer surface of the central portion 22. The lower end surface of the first case 41 is in contact with the upper surface of the peripheral portion 21. The second case 42 is connected to the common conductor 20 such that the upper end surface of the inner surface of the second case 42 is in contact with the outer surface of the central portion 22. The upper end surface of the second case 42 is in contact with the upper surface of the peripheral portion 21.

[0038] The length of the first case 41 in the first direction D1 is between 10 mm and 25 mm. The length of the first case 41 in the second direction D2 is between 10 mm and 40 mm. The length of the first case 41 in the third direction D3 is between 5 mm and 25 mm. The second case 42 has the same shape as the first case 41.

[0039] The insulating case 40 includes an insulating material. The insulating material includes, for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), or modified melamine. The insulating material may also include inorganic materials. The inorganic materials include, for example, glass powder and ceramic powder. The glass powder includes, for example, industrial glass powder. The ceramic powder includes, for example, SiO2 powder, Al2O3 powder, talc (Mg3Si4O 10 (OH)2), aluminum nitride (AlN), or silicon nitride (Si3N4), or mixtures thereof.

[0040] The resin 50 is filled inside the insulating case 40 and seals the pair of capacitors C. In this embodiment, the resin 50 is filled inside the insulating case 40 so as to cover the capacitors C. The resin 50 is positioned between the insulating case 40 and the capacitors C, the common conductor 20, and the individual conductors 30. The resin 50 fills the space between the insulating case 40 and the capacitors C, the common conductor 20, and the individual conductors 30. The resin 50 is in contact with the capacitors C, the common conductor 20, and the individual conductors 30.

[0041] The upper edge of resin 50 reaches the position where the lower end of the second portion 32 is embedded, and the lower edge of resin 50 reaches the position where the upper end of the third portion 33 is embedded. The remaining portions of the second portion 32 and the third portion 33 are exposed from resin 50. The upper edge of resin 50 refers to the upper end of both ends of resin 50 in the first direction D1, and the lower edge of resin 50 refers to the lower end of both ends of resin 50 in the first direction D1.

[0042] The resin 50 includes an insulating material. The insulating material includes, for example, a thermosetting resin. The thermosetting resin includes, for example, an epoxy resin, a urethane resin, a phenolic resin, or a silicone resin. The resin 50 may contain different insulating materials. In this embodiment, the resin 50 includes an epoxy resin.

[0043] The length of the first direction D1 of the high-voltage capacitor 1 is equal to the length of the first direction D1 of the individual conductor 30, and is between 30 mm and 60 mm. The length of the second direction D2 of the high-voltage capacitor 1 is equal to the length of the second direction D2 of the common conductor 20, and is between 20 mm and 50 mm. The length of the third direction D3 of the high-voltage capacitor 1 is equal to the length of the third direction D3 of the common conductor 20, and is between 10 mm and 30 mm.

[0044] As explained above, the high-voltage capacitor 1 uses a pair of capacitors C, each having a columnar body 10. This increases the design flexibility compared to a configuration using a single capacitor with multiple through-holes. The distance between the first electrode 11 and the common conductor 20 can be increased, as can the distance between the second electrode 12 and the individual conductors 30. As a result, the electric field strength between conductors can be reduced. Therefore, the reliability of the high-voltage capacitor 1 can be improved.

[0045] Each pair of individual conductors 30 includes a first portion 31 electrically connected to the first electrode 11 and a second portion 32 connected to the first portion 31 via a bent portion 34. The distance L2 at which the second portions 32 are separated in the second direction D2 is longer than the distance L1 at which the first portions 31 are separated in the second direction D2. Therefore, while using the pair of second portions 32 as a pair of tab connectors with a defined spacing, it is possible to suppress the increase in the size of the high-voltage capacitor 1 in the second direction D2.

[0046] The length W2 of the second part 32 is longer than the length W1 of the first part 31. Therefore, a pair of second parts 32 can be used as a pair of tab connectors with defined sizes.

[0047] The element 10 and the common conductor 20 are spaced apart from each other in the third direction D3. Therefore, it is easy to increase the distance between the first electrode 11 and the common conductor 20.

[0048] The insulating case 40 houses a pair of capacitors C inside. The resin 50 is filled inside the insulating case 40, sealing the pair of capacitors C. This suppresses the occurrence of discharge between the first electrode 11 and the common conductor 20, as well as between the second electrode 12 and the individual conductors 30. The resin 50 also provides moisture resistance to the high-voltage capacitor 1.

[0049] While embodiments of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0050] The high-voltage capacitor 1 comprises a pair of capacitors C and a pair of individual conductors 30, but the high-voltage capacitor 1 may comprise three or more capacitors C and three or more individual conductors 30. The insulating case 40 consists of two members, a first case 41 and a second case 42, but may consist of a single member. In this case, the insulating case 40 may be provided with through holes that expose a part of the circumferential portion of the peripheral portion 21.

[0051] The base body 10 has a columnar shape with the first direction D1 as its axial direction, and does not have to be a rectangular parallelepiped shape as long as it has planar first side surfaces 10c and second side surfaces 10d that face each other in the second direction D2. For example, a pair of third side surfaces 10e may be curved. The individual conductors 30 do not have to have bent portions 34, 35.

[0052] The above embodiments and modifications may be combined as appropriate.

[0053] As can be seen from the above-described embodiments and modifications, this specification includes the following embodiments. (Note 1) A pair of capacitors, A common conductor electrically connected to each of the pair of capacitors, The capacitor comprises a pair of individual conductors electrically connected to the corresponding capacitor, The aforementioned pair of capacitors are A base body having a columnar shape with the first direction as its axis, and having a first side surface and a second side surface that face each other in a second direction perpendicular to the first direction, A first electrode is arranged on the first side and electrically connected to the corresponding individual conductor, Each of the following is provided: a second electrode arranged on the second side and electrically connected to the common conductor, The first electrodes are arranged to face each other in the second direction. Viewed from the first direction, the common conductor surrounds the pair of capacitors and the pair of individual conductors. High-voltage capacitor. (Note 2) Each of the pair of individual conductors includes a first portion electrically connected to the first electrode and a second portion connected to the first portion via a bent portion. The distance at which the second parts are separated in the second direction is longer than the distance at which the first parts are separated in the second direction. The high-voltage capacitor described in Appendix 1. (Note 3) In a third direction perpendicular to the first and second directions, the length of the second portion is longer than the length of the first portion. High-voltage capacitors as described in Appendix 1 or 2. (Note 4) The element and the common conductor are spaced apart from each other in a third direction perpendicular to the first and second directions. A high-voltage capacitor as described in one of the following appendices 1 to 3. (Note 5) An insulating case housing the pair of capacitors inside, The insulating case is filled with a resin that seals the pair of capacitors, and further comprises A high-voltage capacitor as described in one of the notes 1 to 4. [Explanation of symbols]

[0054] 1...High-voltage capacitor, 10...Element, 10c...First side, 10d...Second side, 11...First electrode, 12...Second electrode, 20...Common conductor, 30...Individual conductors, 31...First part, 32...Second part, 34...Bent part, 40...Insulating case, 50...Resin, C...Capacitor.

Claims

1. A pair of capacitors, A common conductor electrically connected to each of the pair of capacitors, The capacitor comprises a pair of individual conductors electrically connected to the corresponding capacitor, The aforementioned pair of capacitors are A base body having a columnar shape with the first direction as its axis, and having a first side surface and a second side surface that face each other in a second direction perpendicular to the first direction, A first electrode is arranged on the first side and electrically connected to the corresponding individual conductor, Each of the following is provided: a second electrode arranged on the second side and electrically connected to the common conductor, The first electrodes are arranged to face each other in the second direction. Viewed from the first direction, the common conductor surrounds the pair of capacitors and the pair of individual conductors. The element and the common conductor are spaced apart from each other in a third direction perpendicular to the first and second directions. The pair of individual conductors are facing each other in the second direction. High-voltage capacitor.

2. Each of the pair of individual conductors includes a first portion electrically connected to the first electrode and a second portion connected to the first portion via a bent portion. The distance at which the second parts are separated in the second direction is longer than the distance at which the first parts are separated in the second direction. The high-voltage capacitor according to claim 1.

3. In a third direction perpendicular to the first and second directions, the length of the second portion is longer than the length of the first portion. The high-voltage capacitor according to claim 2.

4. An insulating case housing the pair of capacitors inside, The insulating case is filled with a resin that seals the pair of capacitors, and further comprises A high-voltage capacitor according to any one of claims 1 to 3.

Images