JP7479752B2 - Capacitor case and capacitor - Google Patents

Description

This invention relates to a capacitor case with mounting legs and a capacitor using this capacitor case.

A resin case may be used to house a capacitor element. Due to the characteristics of the material, the walls of a resin case may warp toward the inside of the case. Therefore, in Patent Document 1, ribs are provided to prevent the walls from warping. In addition, Patent Document 2 discloses providing a rib-shaped positioning portion on the inside of the case.

JP 2003-153415 A JP 2002-367857 A

The case may have mounting legs on the wall for fixing the case to an external device. The mounting legs protrude outward from the wall and have, for example, a through hole. The case can be attached to the external device by inserting a fastener such as a bolt through the through hole and a hole provided in the external device.

However, if the wall warps, the orientation and position of the mounting legs will shift, resulting in problems such as poor installation accuracy or even making installation impossible. Providing ribs can prevent wall warping compared to not providing ribs, but depending on the relative positions of the mounting legs and ribs, it may not be possible to sufficiently prevent the mounting legs from shifting.

The present invention aims to provide a capacitor case and a capacitor that can ensure the accuracy of mounting the capacitor to an external device using mounting legs.

The capacitor case 7 of the present invention comprises a case body 71, mounting legs 72 provided on the outer surface of the wall portion 71a of the case body 71, and a rib 73 provided on the inner surface of the wall portion 71a and facing the base end portion 72b of the mounting leg 72 via the wall portion 71a, the rib 73 straddling the inner surfaces of two adjacent wall portions 71a, and the base end portion 72b of the mounting leg 72 facing the rib 73 for more than half the length (L1, L3) of the base end portion 72b of the mounting leg 72.

In the capacitor case 7, the rib 73 is arranged approximately parallel to the longitudinal direction of the base end 72b of the mounting leg 72, and it is preferable that the base end 72b of the mounting leg 72 and the rib 73 face each other for at least half the longitudinal length L1 of the base end 72b of the mounting leg 72.

The capacitor of the present invention is characterized in that the capacitor element 2 is housed in the capacitor case 7 and filled with resin.

The capacitor case of the present invention is provided with a rib that faces the base end of the mounting leg through the wall, so that it can effectively suppress warping of the wall where the mounting leg is provided. In particular, because the base end of the mounting leg faces the rib for more than half the length of the base end of the mounting leg, it is possible to suppress misalignment of the mounting leg due to warping and ensure the accuracy of mounting the capacitor to an external device using the mounting leg.

When the rib is arranged approximately parallel to the longitudinal direction of the base end of the mounting leg and faces the rib for more than half the longitudinal length of the base end of the mounting leg, the length over which the base end of the mounting leg faces the rib can be sufficiently secured, which further reduces misalignment of the mounting leg due to warping and ensures higher accuracy in mounting the capacitor to an external device using the mounting leg.

1 is an exploded perspective view showing a capacitor according to an embodiment of the present invention. FIG. FIG. 2 is a cross-sectional view of a capacitor case. FIG. 2 is a plan view of the capacitor case. FIG. 5a is a cross-sectional view showing a capacitor case according to another embodiment, and FIG. 5b is a plan view of the capacitor case. FIG. 11 is a cross-sectional view showing a capacitor case according to another embodiment. FIG. 11 is a cross-sectional view showing a capacitor case according to yet another embodiment.

Next, one embodiment of the capacitor 1 of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the capacitor 1 of the present invention comprises a plurality of capacitor elements 2, a bus bar 3 (see FIG. 2) connected to the capacitor elements 2, a capacitor case 7 that houses the capacitor elements 2, and resin (not shown) that fills the capacitor case 7. Below, each of the above components will be described, but the concept of "upper and lower" in the description refers to the time of manufacture, or more specifically, the time of resin filling, and does not necessarily dictate the upper and lower during use.

The capacitor element 2 is a film capacitor made by winding a metallized film with metal vapor-deposited on the surface of an insulating film, and has electrode sections 2a, 2b formed by spraying metal on both axial end faces. When viewed from the axial direction, the capacitor element 2 is bale-shaped, specifically with R (radii) at the four corners, and has a flat section 2c and a curved section 2d on the axial outer periphery.

Four capacitor elements 2 of the above configuration are arranged with the electrode portions 2a and 2b facing up and down to form a capacitor element group 21. The number of capacitor elements 2 in the capacitor element group 21 can be changed as appropriate according to the required capacitance.

The busbar 3 includes a first busbar 4 connected to the upper electrode portion 2a of the capacitor element 2 and a second busbar 5 connected to the lower electrode portion 2b.

The first busbar 4 includes a base 41, an external connection portion 42 extending from the base 41, and an element connection portion 43 extending from the base 41. The planar shape of the base 41 is approximately L-shaped. The size of the base 41 is determined so that it overlaps at least partially with all of the electrode portions 2a of the four capacitor elements 2 that constitute the capacitor element group 21. The external connection portion 42 extends upward from one side of the base 41. The external connection portion 42 is provided with a connection hole 42a for connection to an external device. The element connection portion 43 is tongue-shaped and extends from the outer periphery of the base 41.

The second busbar 5 also has a base 51, an external connection portion 52 extending from the base 51, and an element connection portion 53 extending from the base 51. The base 51 of the second busbar 5 is generally U-shaped in side view so that the capacitor element 2 and the first busbar 4 can be arranged between them, and is broadly divided into an upper horizontal portion 51a, a vertical portion 51b extending downward from the long side of the upper horizontal portion 51a, and a lower horizontal portion 51c extending horizontally from the lower end of the vertical portion 51b. The external connection portion 52 extends upward from the side of the upper horizontal portion 51a opposite to the vertical portion 51b. The external connection portion 52 is provided with a connection hole 52a for connection to an external device. The element connection portion 53 is tongue-shaped and extends from one side of the lower horizontal portion 51c.

The first bus bar 4 and the second bus bar 5 are formed by appropriately punching and bending a metal plate such as aluminum or copper.

The first busbar 4 and the second busbar 5 partially overlap as shown in FIG. 2. Specifically, the base 41 of the first busbar 4 and the upper horizontal portion 51a of the second busbar 5 overlap with the second busbar 5 on top. An insulating member 6 is interposed between the base 41 of the first busbar 4 and the upper horizontal portion 51a of the second busbar 5.

The insulating member 6 is larger than the upper horizontal portion 51a of the second bus bar 5, and extends beyond the periphery of the upper horizontal portion 51a of the second bus bar 5 in a plan view. The insulating member 6 is also generally L-shaped in a side view, and covers part of the vertical portion 51b of the second bus bar 5. This ensures insulation between the second bus bar 5 and the upper electrode portion 2a of the capacitor element 2, and between the second bus bar 5 and the first bus bar 4. The insulating member 6 is made of insulating paper, for example. However, it is also possible to simply provide a space that ensures an insulation distance without providing the insulating member 6.

The capacitor case 7 is made of synthetic resin, and the case body 71, mounting legs 72, and ribs 73 are molded as a single unit.

The case body 71 has five walls 71a. Specifically, it has a bottom wall 71a1 that is generally rectangular in plan view, and side walls 71a2 that rise upward from each of the four sides of the bottom wall 71a1. The upper end of the case body 71 (the surface facing the bottom wall 71a1) is open, and an accommodation space capable of accommodating the capacitor element 2 and the bus bar 3 is formed inside.

The mounting legs 72 are provided on the bottom wall 71a1 and the two side wall portions 71a2 rising from the short sides of the bottom wall portion 71a1. The mounting legs 72 of the bottom wall portion 71a1 protrude downward from the outer surface of the bottom wall portion 71a1. The mounting legs 72 of the side wall portion 71a2 protrude horizontally from the outer surface of the side wall portion 71a2. These mounting legs 72 are for attaching the capacitor case 7 to an external device (not shown) and have mounting holes 72a. If the part of the mounting legs 72 on the wall portion 71a (bottom wall portion 71a1, side wall portion 71a2) side is the base end portion 72b, the shape of the base end portion 72b is approximately rectangular in a plane parallel to the wall portion 71a. As shown in Figures 3 and 4, the mounting legs 72 of the side wall portion 71a2 have the base end portion 72b with the longitudinal direction facing up and down and the short side facing horizontally. The mounting hole 72a opens in the horizontal direction. In other words, the mounting hole 72a and the opening 71b of the case body 71 open in directions that are approximately perpendicular to each other. Reference numeral 72c denotes a reinforcing plate that is provided parallel to the opening direction of the mounting hole 72a, and increases the rigidity in the same direction as the opening direction of the mounting hole 72a.

The rib 73 is a plate-like member having a thickness of, for example, about 3 mm and a height (protruding length from the wall portion 71a) of, for example, about 10 mm, and is provided on the inner surface of the wall portion 71a so as to face the base end portion 72b of the mounting leg 72 through the wall portion 71a. That is, as shown in FIG. 4, in a plan view, the rib 73 is located within the width W1 (excluding the reinforcing plate) in the short direction of the base end portion 72b of the mounting leg 72. This rib 73 spans two surfaces, the bottom wall portion 71a1 and the side wall portion 71a2, which are adjacent to each other. In this state, the rib 73 can be said to extend upward (to the mounting leg 72) from the bottom wall portion 71a1 along the side wall portion 71a2. The rib 73 and the base end portion 72b of the mounting leg 72 face each other for more than half the length of the base end portion 72b of the mounting leg 72. More specifically, the extension direction of the rib 73 and the longitudinal direction of the base end 72b of the mounting leg 72 are approximately parallel, and the rib 73 and the base end 72b of the mounting leg 72 face each other for more than half the longitudinal length of the base end 72b of the mounting leg 72. Therefore, if the longitudinal length of the base end 72b of the mounting leg 72 is L1 and the overlap length between the rib 73 and the base end 72b of the mounting leg 72 is L2, the following formula is established.

L1/2 ≦ L2

In this way, by having the ribs 73 and the mounting legs 72 facing each other, warping of the wall portion 71a where the mounting legs 72 are provided can be effectively suppressed. As a result, deviation in the orientation and position of the mounting legs 72 caused by warping of the wall portion 71a is suppressed, and the capacitor case 7 can be attached to an external device using the mounting legs 72 with high precision. In addition, because the mounting legs 72 and the wall portion 71a are reinforced by the ribs 73, the attachment is stable even when the vibration conditions are severe and large stress is applied to the mounting legs 72 and the wall portion 71a.

As shown in FIG. 3, the rib 73 has its upper corners cut out at an angle. Specifically, it is cut in a triangular shape from the contact point with the side wall 71a2 toward the bottom wall 71a1. This is to prevent the upper corners from damaging the contents such as the capacitor element 2 and the bus bar 3 housed in the case body 71. As shown in FIG. 4, the rib 73 is disposed in a dead space D generated in the case body 71. Note that the dead space D is, for example, between the curved surface portions 2d, 2d of the capacitor element 2, between the capacitor element 2 and the side wall 71a2, between the capacitor element 2 and other electronic components not shown, between the electronic components and the side wall 71a2, etc. Note that in this embodiment, the rib 73 is located between the curved surface portions 2d, 2d of the capacitor element 2. In this way, by positioning the rib 73 in the dead space D, it is possible to contribute to the miniaturization of the entire capacitor.

The thickness of the rib 73 may be greater than the thickness (length in the short direction) of the mounting leg 72. However, if the thickness is too large, there is a possibility that sink marks may occur in the wall portion 71a, so it is preferable to keep the thickness at the same level as the wall portion 71a of the case body, for example.

The resin filled in the case body 71 is, for example, epoxy resin. However, it is not limited to this, and various known resins such as urethane resin can be used.

Next, a method for manufacturing the capacitor 1 will be described. First, the base 41 of the first bus bar 4 is placed on the upper electrode portion 2a of the capacitor element 2, and the upper electrode portion 2a of the capacitor element 2 and the first bus bar 4 are electrically connected. Next, the insulating member 6 is placed on the base 41 of the first bus bar 4. Then, the capacitor element 2, the first bus bar 4, and the insulating member 6 are inserted into the second bus bar 5, which is substantially U-shaped, and the lower electrode portion 2b of the capacitor element 2 and the second bus bar 5 are electrically connected. The capacitor element 2, the bus bar 3, and the insulating member 6 thus integrated are housed in the case body 71 so that the external connection portions 42 and 52 protrude upward from the opening 71b of the case body 71, and the case body 71 is filled with resin to complete the manufacture of the capacitor 1.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, the extension direction of the rib 73 and the longitudinal direction of the base end 72b of the mounting leg 72 do not need to be approximately parallel, and may be approximately perpendicular to the longitudinal direction of the base end 72b of the mounting leg 72, as shown in Figures 5a and 5b. Even in this case, if the rib 73 is located within the longitudinal width W2 of the base end 72b of the mounting leg 72, and the rib 73 and the base end 72b of the mounting leg 72 face each other by more than half the lateral length of the base end 72b of the mounting leg 72, that is, if the lateral length of the base end 72b of the mounting leg 72 is L3 and the overlap length between the rib 73 and the base end 72b of the mounting leg 72 is L2, the same effect as the above embodiment can be obtained.

As shown in FIG. 6, the mounting legs 72 and ribs 73 on the bottom wall 71a1 may be opposed to each other. As shown in FIG. 7, the mounting legs 72 may be provided on two adjacent wall surfaces (the bottom wall 71a1 and the side wall 71a2), and one rib 73 may be provided to straddle the base ends 72b of the mounting legs 72. The mounting legs 72 and the rib 73 do not have to be provided near the horizontal center of the wall 71a, but may be provided at positions shifted to the left or right or at the end of the case body 71. The rib 73 may straddle the bottom wall 71a1 and the side wall 71a2, or may straddle the side wall 71a1 and the side wall 71a1. In short, it is sufficient that the rib 73 is provided across the inner surfaces of the two adjacent wall portions 71a, regardless of whether they are the bottom wall portion 71a1 or the side wall portion 71a2.

Although four capacitor elements 2 are used, the number is not limited to four and may be changed as appropriate. The capacitor elements 2 are not limited to film capacitors, and various capacitor elements such as ceramic capacitors may be used, or multiple types of capacitor elements may be combined. The shape of the capacitor elements may also be various shapes such as cylindrical or rectangular.

1 Capacitor 2 Capacitor element 2a One (upper) electrode portion 2b The other (lower) electrode portion 2c Flat portion 2d Curved surface portion 21 Capacitor element group 3 Bus bar 4 First bus bar 41 Base portion 42 External connection portion 42a Connection hole 43 Element connection portion 5 Second bus bar 51 Base portion 51a Upper horizontal portion 51b Vertical portion 51c Lower horizontal portion 52 External connection portion 52a Connection hole 53 Element connection portion 6 Insulating member 7 Capacitor case 71 Case body 71a Wall portion 71a1 Bottom wall portion 71a2 Side wall portion 71b Opening 72 Mounting leg 72a Mounting hole 72b Base end portion 72c Reinforcing plate 73 Rib L1 Longitudinal length L2 of base end portion of mounting leg Length L3 of overlapping portion of base end portion of mounting leg and rib Shortitudinal length W1 of base end portion of mounting leg Shortitudinal width W2 of base end portion of mounting leg The width D of the base end of the mounting leg in the longitudinal direction is dead space.

Claims (3)

a capacitor case comprising a case body, mounting legs provided on an outer surface of a wall of the case body, and ribs provided on an inner surface of the wall and facing base ends of the mounting legs via the wall, the ribs spanning the inner surfaces of two adjacent wall portions, and the base ends of the mounting legs facing the ribs for at least half the length of the base ends of the mounting legs ;
a plurality of capacitor elements, each having a curved surface portion, housed in the capacitor case;
A capacitor, wherein the rib is disposed between the curved portions of the two capacitor elements. The rib is provided approximately parallel to the longitudinal direction of the base end of the mounting leg,
The base end of the mounting leg faces the rib for at least half of the longitudinal length of the base end of the mounting leg.
The capacitor of claim 1. 3. The capacitor according to claim 1, wherein the capacitor case is filled with a resin .

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