Capacitor holder, and capacitor holding structure

A capacitor holder comprises: a holding portion having a cylindrical inner wall surface, at least an outer peripheral portion of the inner wall surface being open, the holding portion being configured to hold a capacitor inserted through the opening into an inside of the inner wall surface; a fixed portion formed integrally with the holding portion and positioned opposite to the opening of the holding portion; a pair of fitting grooves formed at a pair of end surfaces of the fixed portion opposed to each other adjacent to the holding portion, the fitting grooves being configured to fittably engage with end edges of a printed circuit board to extend along a surface of the printed circuit board; and a proximity suppressor configured to suppress portions of the fixed portion where the fitting grooves are formed from being brought into proximity each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This international application claims the priority of the Japanese Patent Application No. 2012-248608 filed in Japan Patent Office on Nov. 12, 2012. The entire disclosure of the Japanese Patent Application No. 2012-248608 is incorporated herein by reference.

TECHNICAL FIELD

This invention relates to a capacitor holder configured to hold a capacitor on a printed circuit board, and to a capacitor holding structure having a combination of the capacitor holder and a printed circuit board. More specifically, this invention relates to a capacitor holder and a capacitor holding structure configured to hold a cylindrical capacitor lying on its side.

BACKGROUND ART

In recent years, electronic components mounted on a printed circuit board have been required to further reduce their heights (i.e., exhibit less heights on the printed circuit board) in accordance with the downsizing and thinning of electronic equipment.

A capacitor, when mounted upright on the printed circuit board, becomes relatively high on the printed circuit board. In some cases, therefore, the capacitor is laid on the printed circuit board (i.e. the capacitor is disposed such that the axial direction thereof becomes substantially parallel to the surface of the printed circuit board) thereby to decrease the protruding amount of the capacitor from the printed circuit board.

As a capacitor holder configured to hold the capacitor laid on the printed circuit board, for example, there is proposed a capacitor holder including a holding portion made of a resin having a cylindrical inner wall surface and an opening formed in at least an outer peripheral portion of the inner wall surface and, holding the capacitor inserted into the inside of the inner wall surface through the opening while the resin thereof is elastically deformed. There is also proposed the holding portion provided with a plurality of hooked legs engageable with holes formed in the printed circuit board at the position opposite to the opening. By engaging the legs with the holes, the capacitor holder is mounted on the printed circuit board (see, for example, Patent Literature 1).

PRIOR ART DOCUMENTS

Patent Documents

PATENT DOCUMENT 1: Japanese Design Registration No. 1360657

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, using only the hooked engaging portion for holding a capacitor as described in Patent Document 1 does not always provide a sufficient holding force. This applies in particular to the case in which the capacitor is inserted into the capacitor holder preliminarily mounted on the printed circuit board. In this case, if the holding portion is forcefully opened when the capacitor is inserted, the legs may approach each other in reaction thereto, and easily disengaged from the holes.

According to one aspect of the invention, in a capacitor holder and a capacitor holding structure configured to hold a cylindrical capacitor laid on a printed circuit board, it is preferred to enhance the force of holding the capacitor by inhibiting the capacitor holder from disengaging from the printed circuit board.

Means for Solving the Problems

A capacitor holder according to the invention comprises: a holding portion made of a resin to have a cylindrical inner wall surface, at least an outer peripheral portion of the inner wall surface being open, the holding portion being configured to hold a capacitor inserted through the opening into an inside of the inner wall surface while elastically deforming the resin; a fixed portion formed of the resin integrally with the holding portion and positioned opposite to the opening of the holding portion; a pair of fitting grooves formed at a pair of end surfaces of the fixed portion opposed to each other adjacent to the holding portion, the pair of fitting grooves being configured to fittably engage with end edges of a printed circuit board to extend along a surface of the printed circuit board; and a proximity suppressor formed of the resin as a part of the fixed portion and configured to suppress portions of the fixed portion where the fitting grooves are formed from being brought into proximity each other.

The capacitor holder according to the invention configured as described above is in use together with the printed circuit board comprising a hole. The hole has inner wall surfaces extending in parallel to each other and opposed to each other with interposition of a clearance through which the pair of fitting grooves provided to the fixed portion simultaneously fittably engage therewith. In the capacitor holder according to the invention in use, the fitting grooves are engaged with the inner wall surfaces of the hole. The portions of the fixed portion where the fitting grooves are formed are suppressed by the proximity suppressor from approaching each other. Thus, it is difficult to engage the fitting grooves with the inner wall surfaces of the hole by bringing the fitting grooves into proximity with each other. In view of the above, when the capacitor holder according to the invention is mounted on the printed circuit board, the hole is directly extended to the end edges of the printed circuit board, or alternatively, the hole having the inner wall surfaces is preliminarily provided continuously with a wide width portion sized to allow the pair of end surfaces to simultaneously penetrate therethrough. With this arrangement, the fixed portion is moved along the inner wall surfaces of the hole from either the end edges of the printed circuit board or the inside of the wide width portion. Accordingly, the opposing inner wall surfaces of the hole are fittably engaged to the fitting grooves.

The holding portion of the capacitor holder, which continuously connected from the fixed portion, has the cylindrical inner wall surface, and at least an outer peripheral portion of the inner wall surface is open. When the capacitor is inserted through the opening into the inside of the inner wall surface while elastically deforming the resin, the holding portion holds the capacitor. The fixed portion is integrally formed at the position opposite to the opening of the holding portion. Thus, the capacitor holder according to the invention can hold a cylindrical capacitor on the printed circuit board in an overturned posture. In addition, as described above, the portions of the fixed portion where the fitting grooves are formed are suppressed by the proximity suppressor from approaching each other. This arrangement suppresses the fixed portion from being easily disengaged from the printed circuit board. Accordingly, the holding force with which the capacitor is held is enhanced.

In the capacitor holder according to the invention, the fitting grooves may be formed at positions not to cross a cylindrical surface in contact with the inner wall surface. The cylindrical surface means a hypothetical surface of a cylindrical object inserted into the holding portion. In the above configuration, a clearance is formed between the capacitor held by the inner wall surfaces of the holding portion and the printed circuit board that is fittably engaged to the fitting grooves. With this arrangement, the capacitor is not in contact with the printed circuit board. Accordingly, the generation of a so-called chattering, which is the repeated contacting of the capacitor with the printed circuit board due to vibrations or the like, is favorably suppressed.

In the capacitor holder according to the invention, an end surface of the fixed portion including the proximity suppressor may be in contact with a cylindrical surface in contact with the inner wall surface, the end surface being opposite to the opening. The cylindrical surface means a hypothetical surface of a cylindrical object inserted into the holding portion. In the above configuration, the protruding amount of the capacitor holder by which the capacitor holder protrudes from the back surface of the printed circuit board is equal to the protruding amount of the capacitor by which the capacitor protrudes from the back surface. Hence, the printed circuit board including the capacitor and the capacitor holder exhibits further less height.

A capacitor holding structure according to the invention comprises: the capacitor holder according to any one of the above; and a printed circuit board comprising a hole having: narrow width portions having inner wall surfaces opposed to each other and extending in parallel to each other, the inner wall surfaces being interposed with a clearance that allows the pair of fitting grooves to simultaneously engage therewith; and a wide width portion continuously connected from the narrow width portions and sized to allow the pair of end surfaces to simultaneously penetrate therethrough.

In the capacitor holding structure according to the invention configured as described above, the fixed portion of the capacitor holder is inserted into the wide width portion of the hole formed in the printed circuit board, and moved toward the narrow width portions. With this arrangement, the paired fitting grooves of the fixed portion are in use engaged with the inner wall surfaces of the narrow width portions. Specifically, in the capacitor holding structure according to the invention, by providing the printed circuit board with the hole having the narrow width portions and the wide width portion described above, the capacitor holder according to the invention can be easily mounted. The capacitor holder thus exhibits a high holding force as described above.

In the above configuration, the narrow width portions may be formed into a plurality of lines in which the inner wall surfaces extend in parallel to each other. Further, the wide width portion may bring the narrow width portions into communication with each other in the direction in which the inner wall surfaces are opposed to each other. With this arrangement, by mounting capacitor holders according to the invention on the narrow width portions, a plurality of capacitors can be held in parallel to each other.

In the description that follows, the exemplary embodiments according to the invention will be described.

EXPLANATION OF REFERENCE NUMERALS

MODE FOR CARRYING OUT THE INVENTION

FIGS. 1A to 1Gillustrate the configuration of an exemplary capacitor holder1according to an embodiment of this invention.FIG. 1Ais a plan view thereof,FIG. 1Bis a front view thereof,FIG. 1Cis a bottom view thereof,FIG. 1Dis a rear view thereof,FIG. 1Eis a left lateral view thereof,FIG. 1Fis a right lateral view thereof, andFIG. 1Gis a perspective view thereof.

In the following description, the relative positional relationship between the respective portions of the capacitor holder1will be described with reference to the directions, such as front and back, right and left, and top and bottom directions, as indicated in the arrows inFIGS. 1A to 1G. That is, the lower side shall mean the side at which the capacitor holder1is mounted on the printed circuit board20(seeFIG. 2). The front side shall mean the side at which the center of a capacitor40(seeFIG. 4B) is opposed to the capacitor holder1. However, these directions are merely definitions for describing the relative positional relationship between the respective portions of the capacitor holder1. In other words, these directions have nothing to do with the mounting directions where the capacitor holder1is actually in use.

As illustrated inFIGS. 1A to 1G, the capacitor holder1comprises holding portions5at upper positions on a fixed portion3. A fixed portion3is fixed on the printed circuit board20. The holding portions5hold the capacitor40. The fixed portion3and the holding portions5are integrally formed of an electrically insulating resin (such as polyamide, polypropylene, and polyethylene). The holding portions5are a pair of thin pieces protruding along the cylindrical surface respectively from upper right and left ends of the fixed portion3. An opening5A is formed between upper ends of the holding portions5. In addition, recesses3A are formed in the fixed portion3. The recesses3A have cylindrical inner wall surfaces continuously connected from the cylindrical inner wall surface of the holding portions5, respectively. An opening3B is formed between lower ends of the recesses3A.

A wall3C (an example of a proximity suppressor) stands upright from the back end of the recesses3A. The wall3C is continuously connected from the recesses3A on both sides of the opening3B. The wall3C extends only to a position lower than the holding portions5. A semicircular cutout3D is formed in the wall3C at a position opposed to an explosion proof valve (not illustrated) of the capacitor40. The explosion proof valve is provided to a distal end41of the capacitor40. Right and left end surfaces of the fixed portion3are provided with fitting grooves3E, respectively. The grooves3E penetrate through the fixed portion3in the front and back direction. The cross-sectional shape of each fitting groove3E is rectangular with one side opened. The fitting grooves3E can be fitted to the end edges of the printed circuit board20along the surface of the printed circuit board20.

[Example of Capacitor Holding Structure Using the Above Capacitor Holder]

The capacitor holder1configured as described above is in use mounted on, for example, the printed circuit board20provided with a hole21as illustrated inFIG. 2. As illustrated inFIG. 2, the hole21comprises a pair of narrow width portions21A and a wide width portion21B. The narrow width portions21A each have a pair of inner wall surfaces at right and left sides. The inner wall surfaces are opposed to each other while extending in parallel to each other, with interposition of a clearance that allows the paired fitting grooves3E to simultaneously engage therewith. The wide width portion21B is sized to tolerate the penetration of the fixed portion3in the upper and lower direction. In this example, the paired narrow width portions21A are positioned at both sides of the wide width portion21B in the front and back direction while the centers of the narrow width portions21A in the right and left direction are coincident with the center of the wide width portion21B in the right and left direction. In other words, the hole21as a whole is shaped like a cross.

The length of the hole21is the sum of the lengths of the narrow width portion21A, wide width portion21B and narrow width portion21A that are continuously connected in the front and back direction. The length of the hole21is set to be slightly greater than the axial length of the capacitor40. In addition, a pair of lead holes23through which leads43provided at a base end42of the capacitor40penetrate are formed at positions outside the end of one of the narrow width portions21A, such as a further front side of a front narrow width portion21A.

The fixed portion3of the capacitor holder1is inserted through the wide width portion21B. The paired fitting grooves3E are fitted into the narrow width portion21A located backward than the capacitor holder1. Then, the capacitor holder1is slid to the back end of the narrow width portion21A and used.FIGS. 3A to 3Eillustrate the capacitor holding structure in which the capacitor holder1is mounted on the printed circuit board20.FIG. 3Ais a back view thereof,FIG. 3Bis a plan view thereof,FIG. 3Cis a front view thereof,FIG. 3Dis a bottom view thereof, andFIG. 3Eis a right lateral view thereof.

The capacitor40is inserted into the capacitor holding structure configured as above. Specifically, the capacitor40is inserted into the inner wall surfaces of the holding portions5and the recesses3A through the opening5A of the capacitor holder1while elastically deforming the holding portions5. Then, the holding portions5return to their respective original positions after the insertion of the capacitor40, and hold the capacitor40.FIG. 4A to 4Eillustrate a state in which the capacitor40is mounted on the capacitor holding structure.FIG. 4Ais a back view thereof,FIG. 4Bis a plan view thereof,FIG. 4Cis a front view thereof,FIG. 4Dis a bottom view thereof, andFIG. 4Eis a right lateral view thereof.

As illustrated inFIGS. 4A to 4E, after the capacitor40is laid and held by the capacitor holder1as described above, the leads43are inserted into the lead holes23. Subsequently, the capacitor holder1and the capacitor40are masked from below and then passed through a flow solder tank. Soldering is therefore performed on the printed circuit board20on which the capacitor40is thus fixed.

Further, as illustrated inFIG. 5(the cross sectional view taken along the X-X line inFIG. 4E), the cylindrical surface of the capacitor40contacts the inner wall surfaces of the holding portions5and the recesses3A described above. The fitting grooves3E are provided at positions not to cross the cylindrical surface of the capacitor40. Thus, a clearance is formed between the capacitor40held by the inner wall surfaces and the printed circuit board20. The capacitor40is therefore not in contact with the printed circuit board20. Hence, the generation of a so-called chattering, which is the repeated contacting of the capacitor40with the printed circuit board20due to vibrations or the like, is favorably suppressed. As described above, in this embodiment, the capacitor40can be held without contacting the printed circuit board20even at a single position. Thus, in this embodiment, the capacitor40and the printed circuit board20are also thermally insulated from each other.

As illustrated inFIG. 5, the lower end surface of the fixed portion3including the wall3C is in contact with the cylindrical surface of the capacitor40, which is in contact with the inner wall surfaces of the holding portions5and the recesses3A. Thus, the protruding amount of the capacitor holder1by which the capacitor holder1protrudes from the back surface (lower surface) of the printed circuit board20is equal to the protruding amount of the capacitor40by which the capacitor40protrudes from the back surface. Thus, the printed circuit board20including the capacitor40and the capacitor holder1can be successfully provided as one with less height. Further, the protruding amount of the fixed portion3by which the fixed portion3protrudes to the back of the printed circuit board20is small as compared to an arrangement where a known hook is used for the fixation. Hence, the printed circuit board20including the capacitor40and the capacitor holder1can be more successfully provided as one with less height.

[Other Example of Capacitor Holding Structure Using the Above Capacitor Holder]

Next,FIG. 6is a plan view of another example of the printed circuit board20on which the capacitor holder1is to be mounted. The hole21of the printed circuit board20of this example comprises three parallel lines of the narrow width portions21A at each of the front and back positions. The wide width portions21B corresponding to the respective narrow width portions21A are in communication with each other, thereby forming a single wide width portion21B. In this case, the hole21is an integrated hole. Alternatively, for example, the capacitor holders1can be attached to three backward narrow width portions21A as the example described above to form capacitor holding structures. Therefore, three capacitors40can be placed and held in parallel.FIGS. 7A to 7Erespectively illustrate a state in which the capacitors40are mounted on the capacitor holding structure of this example.FIG. 7Ais a back view thereof,FIG. 7Bis a plan view thereof,FIG. 7Cis a front view thereof,FIG. 7Dis a bottom view thereof, andFIG. 7Eis a right lateral view thereof.

In each of the capacitor holding structures described above, the capacitor40may be first mounted on the capacitor holder1, and then the capacitor holder1may be mounted on the printed circuit board20. In addition, the capacitor holder1may hold a base end42. In such configuration, the leads43are inserted into the lead holes23through the cutout3D. Further, both ends of the capacitor40may be held by the capacitor holder1. Such configuration can more successfully suppress the chattering from being caused by the contacting of the capacitor40with the printed circuit board20.

The invention is not limited at all to the embodiments as described above. The invention may be variously carried out within the scope not departing from the gist of the invention. The lower surface of the fixed portion3may be continuously connected as a whole, and shaped like a rectangular plate, for example. Further, the invention is not limited to the technical field where the capacitor40is held in parallel to the printed circuit board20. The invention is likewise applicable to a technical field, for example, where the capacitor40is held substantially in parallel to the printed circuit board20at an angle of, for example, 10 degrees or less. Each portion may be designed so that the lateral surfaces (lower surface) of the capacitor40extend from the lower surface of the fixed portion3. In addition, a back portion of the fixed portion3may be provided with a fitting groove configured to fittably engage with the narrow width portion21A.