Switching power supply

A switching power supply has electronic parts that configure a switching circuit. The electronic parts are accommodated in a casing. A seat member is formed unitarily with the casing on which the electronic parts are mounted. A coolant channel is formed through the seat member so as to be open at least at two positions of an outer wall surface of the casing. Coolant that flows through the coolant channel cools the electronic parts mounted on the seat member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2010-101805 filed Apr. 27, 2010, the description of which is incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

1. Technical Field of the Disclosure

The present disclosure relates to a switching power supply provided with a casing for accommodating electronic parts.

2. Related Art

It is well known that a switching power supply that includes electronic parts has a casing for accommodating the electronic parts.

FIGS. 16 and 17illustrate such a switching power supply90based on conventional art. The switching power supply90is provided with a casing92accommodating electronic parts91.

The casing92is provided with a coolant channel93through which a coolant97flows to cool the electronic parts91. For example, such a switching power supply is disclosed in JP-A-2004-297887.

In the interior of the casing92of the switching power supply90, the electronic parts91are mounted on the bottom surface. In the exterior of the casing92, a serpentine recess930that will serve as the coolant channel93is formed.

The casing92is provided with a channel cover94which is attached and fixed thereto by bolts990or the like. The recess930, together with the channel cover94, forms an enclosed serpentine space outside the casing92, which space serves as the coolant channel93.

Also, in order to prevent leakage of the coolant97, a sealing member99(seeFIG. 16) is interposed between the channel cover94and the casing92. The casing92is also provided with a protective cover920for protecting the electronic parts91.

The channel cover94is formed with an inlet95and an outlet96for the coolant97. The coolant97charged from the inlet95flows through the coolant channel93and discharged from the outlet96. Thus, the electronic parts91are cooled.

However, the switching power supply90based on the conventional art needs such parts as the channel cover94, the bolts990and the sealing member99, besides the casing92, to form the coolant channel93. Thus, the switching power supply90of the conventional art has suffered from a problem of needing a number of parts.

Also, in order to screw the bolts990, female thread portions98(seeFIG. 17) are required to be formed in the casing92. Therefore, there has been a problem that the size of the casing92is likely to be increased.

In addition, the switching power supply90of the conventional art requires a step of fastening the channel cover94to the casing92using the bolts990and a step of interposing the sealing member99between the channel cover94and the casing92. Thus, the switching power supply90of the conventional art has also suffered from a problem of increasing the number of steps.

SUMMARY OF THE DISCLOSURE

An embodiment provides a compact-size switching power supply which is manufactured with a reduced number of parts and a reduced number of steps.

In a switching power supply according to a first aspect, the switching power supply includes electronic parts that configure a switching circuit, a casing that accommodates the electronic parts, a seat member formed unitarily with the casing on which the electronic parts are mounted, and a coolant channel formed through the seat member so as to be open at least at two positions of an outer wall surface of the casing. Coolant that flows through the coolant channel cools the electronic parts mounted on the seat member.

In the switching power supply according to a second aspect, the coolant channel includes a primary channel formed through the seat member, and a secondary channel extended in a direction of intersecting the primary channel for connection thereto, and the connection is established at a position between end portions of the primary channel, with one end of the secondary channel being open in an outer wall surface of the casing.

One end portion of the end portions of the primary channel is provided with a stopper so that the coolant flows from the other end portion to the secondary channel through the primary channel.

In the switching power supply according to a third aspect, the coolant channel includes a primary channel formed through the seat member, and a pair of secondary channels extended in a direction of intersecting the primary channel for connection thereto, and the connection is established at a position between end portions of the primary channel, with one end of the secondary channel being open in an outer wall surface of the casing

Each of the end portions of the primary channel is provided with a stopper so that the coolant flows from one of the secondary channel to the other one of the secondary channel through the primary channel.

With this configuration, the degree of freedom of designing the switching power supply is enhanced.

Specifically, in the above configuration, one secondary channel may be used as an inlet of a coolant and the other secondary channel may be used as an outlet of the coolant. Since the secondary channels may be formed at optional positions between both ends of the primary channel, the positions of the inlet and the outlet of the coolant can be freely determined.

In the switching power supply according to a fourth aspect, the pair of secondary channels are extended in the same direction, the primary channel has a first side face on a side to which the pair of secondary channels are connected.

The first side face resides between the pair of secondary channels, and a second side face resides on an opposite side of the first side face with reference to the secondary channel on a downstream side.

The first side face coincides with the second side face regarding the position in a direction in which the secondary channels are extended.

With this configuration, pressure loss of the coolant is reduced. Specifically, let us assume that the first side face (seeFIG. 15) of the primary channel does not coincide with the second side face thereof regarding the position in a direction in which the secondary channel is projected.

In this case, eddies will be caused in the coolant in a region including the second side face, and thus there is a tendency that pressure loss of the coolant is increased. In this regard, the above configuration is likely to allow the coolant to stay in the region including the second side face.

Accordingly, the fresh coolant is inhibited from entering the region to thereby allow the coolant to smoothly flow from the primary channel toward the secondary channel on a downstream side. In this way, pressure loss of the coolant is reduced.

In the switching power supply according to a fifth aspect, a cross-sectional area of the secondary channel, which is perpendicular to a direction of flow of the coolant, is made smaller than that of the primary channel.

A larger cross-sectional area of the primary channel will cause smaller pressure loss when the coolant flows, and also will achieve higher cooling efficiency. Meanwhile, a larger cross-sectional area of the secondary channels will also cause smaller pressure loss in the coolant.

However, if electronic parts are mounted above the primary channel, the larger cross-sectional area of each of the secondary channels will not so much contribute to raising the efficiency of cooling the electronic parts.

In addition, if the cross-sectional area of each secondary channel is made larger, a pipe or the like to be connected to the secondary channel is required to have a larger diameter accordingly, departing from the advantages such as of using a general-purpose pipe.

In this regard, with the above configuration of the present disclosure, each secondary channel may have a diameter in conformity with a general-purpose pipe or the like to be connected thereto, while the primary channel may have a larger cross-sectional area. In this way, pressure loss of the coolant is reduced and the efficiency of cooling the electronic parts is enhanced.

In the switching power supply according to a sixth aspect, the seat member has major surfaces on both sides thereof with an interposition of the coolant channel, different electronic parts are mounted on the major surfaces, and the electronic part mounted on one of the major surface of the seat member configures a switching circuit, while the electronic part mounted on the other one of the major surface of the seat member configures another switching circuit.

With the above configuration, two switching circuits are configured in a single casing.

Also, the electronic parts configuring the individual switching circuits are cooled using a single coolant channel. Thus, the number of casings and the number of coolant channels can both be reduced, whereby the switching power supply is manufactured at lower cost.

Further, since no stopper of the coolant channel is provided on the surface where the electronic parts are mounted, the coolant is prevented from flowing onto the surface of mounting the electronic parts.

Otherwise, the coolant would flow onto the surface of mounting the electronic parts in the event the coolant has leaked from a sealing portion between the stopper and the casing. Thus, the coolant will flow out of the switching power supply in the event of such leakage without flowing onto the surface of mounting the electronic parts.

Therefore, breakage or the like of the electronic parts would not be caused in the switching power supply.

In the switching power supply according to a seventh aspect, the switching power supply further includes a protective cover that covers the casing, and a weakly cooled area formed unitarily with the casing for mounting the electronic parts.

The amount of heat generated by the electronic parts mounted on the seat member is larger that of the electronic parts mounted on the weakly cooled area, and a distance from the seat member to the protective cover is shorter than a distance from the weakly cooled area to the protective cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the accompanying drawings, hereinafter will be described several embodiments of the present disclosure.

Referring toFIGS. 1 to 5, hereinafter is described a switching power supply according to a first embodiment of the present disclosure.FIG. 1is a perspective view illustrating a switching power supply1according to the first embodiment.

As shown inFIG. 1, the switching power supply1of the present embodiment includes a switching circuit13, electronic parts2configuring the switching circuit13, a seat member4on which the electronic parts2are mounted and a coolant channel5through which a coolant10flows.

The electronic parts2are accommodated in a casing3. The seat member4is integrally formed with the casing3. The coolant channel5is formed through the seat member4so as to be open at least at two positions of an outer wall surface30of the casing3.

The coolant10that flows through the coolant channel5cools the electronic parts2mounted on the seat member4.

Specific description is set forth below.

As shown inFIG. 1, the coolant channel5has end portions6at both ends thereof, each of which is connected to a pipe12. Piping, such as a hose (not shown), is attached to the pipes12to flow the coolant10through the coolant channel5of the switching power supply1.

The casing3accommodates a plurality of electronic parts2. Of the electronic parts2, those electronic parts2awhich easily generate heat are mounted on the seat member4, however, those electronic parts2bwhich generate small amount of heat are not mounted on the seat member4.

FIG. 2is a perspective view illustrating a method of manufacturing the casing3of the first embodiment. As shown inFIG. 2, the casing3and the seat member4are integrally formed by casting.

Specifically, a plurality of casting mold parts8ato8care assembled to provide a casting mold8into which molten metal is cast. Then, the molten metal is cooled and solidified, followed by withdrawing the casting mold parts8ato8cin the arrowed directions indicated inFIG. 2to take out the casing3.

The casting mold part8ahas a projection81corresponding to an accommodating space31of the casing3. The casing molds8band8chave columnar portions82and83, respectively.

When the casting mold parts8band8care assembled, the columnar portions82and83are joined and the joined portions form a portion corresponding to the coolant channel5.

It should be appreciated that the columnar portions82and83may be integrated into a single columnar portion to provide a casting mold part having a single columnar portion. Alternatively, instead of the columnar shape, the portions82and83may have a different shape in conformity with the shape of electronic parts to be mounted.

FIG. 3is a vertical cross-sectional view illustrating the switching power supply1of the first embodiment taken along a B-B line ofFIG. 4.FIG. 4is a horizontal cross-sectional view taken along an A-A line ofFIG. 3.

After integrally molding the casing3and the seat member4, the pipes12are attached, as shown inFIG. 4, to the respective end portions6of the coolant channel5.

Further, as shown inFIG. 3, the electronic parts2are accommodated in the casing3, and a protective cover11is attached to the casing3to protect the electronic parts2.

As shown inFIGS. 3 and 4, the casing3has a weakly cooled area32for mounting the electronic parts2bthat generate less heat. Meanwhile, the seat member4has a mounting surface40for mounting the electronic parts2athat easily generate heat, or generate large amount of heat.

The height from the weakly cooled area32to the protective cover11is h2which is larger than h1that is the height from the mounting surface40to the protective cover11. In this way, the electronic parts2b, if they have a large size, are ensured to be mounted in the weakly cooled area32.

The electronic parts2athat generate large amount of heat include, for example, semiconductor modules incorporating switching elements. The electronic parts2bthat generate small amount of heat include, for example, capacitors or reactors.

FIG. 5is a vertical cross-sectional view illustrating the switching power supply1of the first embodiment, in which the level of the weakly cooled area32is brought to the same level as that of the mounting surface40of seat member4.

As shown inFIG. 5, if the height of the electronic part2bmounted on the weakly cooled area32is not so large, the weakly cooled area32may be permitted to reside in the plane extended from the mounting surface40of the seat member4.

Hereinafter are described advantages and effects of the present embodiment.

In the present embodiment, the seat member4for mounting the electronic parts2is integrated with the casing3, with the coolant channel5being formed through the seat member4. Thus, in forming the coolant channel5, the number of parts can be reduced, and at the same time, the size of the casing3can be reduced.

Specifically, for example, let us compare the present embodiment with the case, as shown inFIG. 16, where the casing92is assembled with the channel cover94to form the coolant channel93.

As will be understood from the comparison, the present embodiment dispenses with the channel cover94, the bolts990, and the like, and thus the number of parts can be reduced.

The present embodiment also dispenses with the female thread portions98for screwing the bolts990(seeFIG. 16), whereby the size of the casing3can be reduced.

Further, the coolant channel5is formed through the seat member4which is integrated into the casing3. Therefore, assemblage of a separately provided member is not necessary in forming the coolant channel5. In other words, the step such as of connecting the channel cover94(seeFIG. 16) to the casing92, for example, can be omitted. Thus, the number of steps for manufacturing the switching power supply1is reduced.

As mentioned above, the electronic parts2athat generate a large amount of heat include, for example, semiconductor modules whose height is small in general.

Therefore, when such semiconductor modules are arranged on the seat member4in which the coolant channel5is formed, adjustment to approximately the same height as the height h2is possible. In this way, the dead space in the switching power supply is reduced to thereby reduce the size of the switching power supply.

As described above, in the switching power supply1according to the present embodiment, the size, the number of parts, and the number of steps are all reduced.

Referring toFIGS. 6 and 7, hereinafter is described a second embodiment of the present disclosure.FIG. 6is an explanatory view illustrating a method of manufacturing the casing3according to the second embodiment.FIG. 7is a horizontal cross-sectional view illustrating the casing3of the switching power supply1according to the second embodiment.

It should be appreciated that, in the second and the subsequent embodiments, the components identical with or similar to those in the first embodiment are given the same reference numerals for the sake of omitting explanation.

The second embodiment is different from the first embodiment in that the shape of the coolant channel5has been changed.

As shown inFIG. 7, the coolant channel5of the present embodiment includes a primary channel50and a secondary channel51. The primary channel50is formed through the seat member4. The secondary channel51is extended in the direction of intersecting the primary channel50for connection thereto.

The connection is established at a position between the end portions6aand6bof the primary channel50, with one end of the secondary channel51being open in the outer wall surface30of the casing3. Of the end portions6aand6bof the primary channel50, the end portion6ais provided with a stopper7so that the coolant10will flow, for example, from the end portion6bto the secondary channel51through the primary channel50.

In the present embodiment as well, the casing3is integrally formed with the seat member4by casting. Specifically, as sown inFIG. 6, a plurality of casting mold parts8dto8fare assembled to form the casting mold8, followed by casting molten metal in the casting mold8.

Then, the cast molten metal is cooled for solidification, followed by withdrawing the casting mold parts8dto8fin the arrowed directions indicated inFIG. 6.

It should be appreciated that the cross-sectional area of the secondary channel51, which is perpendicular to the direction of flow of the coolant10, is made smaller than that of the primary channel50.

The remaining configuration is similar to the first embodiment.

The advantages and effects of the second embodiment will be described below.

The configuration of the second embodiment contributes to enhancing the degree of freedom of designing the switching power supply1. Specifically, when the primary channel50alone is provided, the end portion6aof the primary channel50necessarily has to be an inlet of the coolant, while the end portion6bnecessarily has to be an outlet of the coolant.

Thus, the positions of the inlet and the outlet cannot be freely changed. However, as shown inFIG. 7, with the configuration of the present embodiment, the secondary channel51is formed at an optional position between the end portions6aand6bof the primary channel50. Accordingly, the position of at least one of the inlet and the outlet of the coolant is freely determined.

Also, with the above configuration of the present embodiment, the secondary channel may have a diameter in conformity with a general-purpose pipe or the like to be connected thereto, while the primary channel may have a larger cross-sectional area. In this way, pressure loss of the coolant is reduced and the efficiency of cooling the electronic parts is enhanced.

Other advantages and effects are similar to those of the first embodiment.

Referring toFIG. 8, a third embodiment of the present disclosure is described.FIG. 8is a horizontal cross-sectional view illustrating the casing3of the switching power supply1according to the third embodiment.

As shown inFIG. 8, the coolant channel5of the third embodiment includes the primary channel50and a pair of secondary channels51aand5ab. The primary channel50is formed through the seat member4.

The pair of secondary channels51aand51bis extended in the direction of intersecting the primary channel50for connection thereto. The connections are established at the positions between the end portions6aand6bof the primary channel50.

The secondary channels51aand51beach have an end which is open in the outer wall surface30of the casing3. Each of the end portions6aand6bof the primary channel50is provided with the stopper7so that the coolant10will flow, for example, from the secondary channel51ato the secondary channel51bthrough the primary channel50.

The remaining configuration is similar to the first embodiment.

The advantages and effects of the third embodiment are described.

The configuration of the third embodiment contributes to further enhancing the degree of freedom of designing the switching power supply1.

Specifically, in the configuration of the third embodiment, the secondary channel51amay be used as an inlet of the coolant, for example, while the secondary channel51bmay be used as an outlet of the coolant.

Since the secondary channels51aand51bare formed at optional positions between the end portions6aand6bof the primary channel50, the positions of the inlet and the outlet of the coolant can be freely determined.

Other advantages and effects are similar to those of the first embodiment.

Referring toFIG. 9, hereinafter is described a fourth embodiment of the present disclosure.FIG. 9is a horizontal cross-sectional view illustrating the casing3of the switching power supply1according to the fourth embodiment.

As shown inFIG. 9, the coolant channel5of the fourth embodiment includes the primary channel50and a pair of secondary channels51aand51b. A stopper7ais attached to the end portion6aof the primary channel50.

Another stopper7bis provided in the primary channel50so as to be positioned nearer the end portion6awith reference to the end portion6b. The pair of secondary channels51aand51bis connected to the primary channel50. The connection is established at positions between the stoppers7aand7b.

The remaining configuration is similar to the first embodiment.

The advantages and effects of the fourth embodiment are described.

The configuration of the present embodiment is effective in the case where the electronic parts2are mounted only in an area corresponding to the area that falls between the stoppers7aand7b. In the present embodiment, since one of the stoppers is provided at a position near the secondary channel51b, the volume of the coolant in the channel is reduced.

Other advantages and effects are similar to those of the first embodiment.

Referring toFIG. 10, a fifth embodiment of the present disclosure is described.FIG. 10is a horizontal cross-sectional view illustrating the casing3of the switching power supply1according to the fifth embodiment.

In the fifth embodiment, the shape of the coolant channel5has been changed. As shown inFIG. 10, the pair of secondary channels51aand51bof the present embodiment are extended in the same direction.

The primary channel50has a first side face53aon the side to which the pair of secondary channels51aand51bare connected, the first side face53aresiding between the pair of secondary channels51aand51b.

The primary channel50also has a second side face53bresiding on the opposite side of the first side face53awith reference to the secondary channel51bon a downstream side.

The first side face53acoincides with the second side face53bregarding the position in a direction X in which the secondary channels51aand51bare extended.

The remaining configuration is similar to the first embodiment.

The advantages and effects of the fifth embodiment are described.

The configuration of the fifth embodiment contributes to reducing pressure loss of the coolant10.

FIG. 15is a horizontal cross-sectional view of a casing of a switching power supply according to a comparative example.

As shown inFIG. 15, let us assume that a first side face86aof a primary channel84does not coincide with a second side face86bthereof regarding the position in a direction x in which secondary channels82and83are projected. In this case, eddies will be caused in a coolant81in a region840in the primary channel84, the region840including the second side face86a, and thus there is a tendency that pressure loss of the coolant81is increased.

In this regard, as shown inFIG. 10, the configuration of the present embodiment is likely to allow the coolant10to stay in a region50ain the primary channel50, the region50aincluding the second side face53b.

Accordingly, the coolant10is unlikely to newly enter the region50ato thereby allow the coolant10to smoothly flow from the primary channel50toward the secondary channel51bon a downstream side. In this way, pressure loss of the coolant10is reduced.

Other advantages and effects are similar to those of the first embodiment.

Referring toFIG. 11, a sixth embodiment of the present disclosure is described.FIG. 11is a vertical cross-sectional view illustrating the casing3of the switching power supply1according to the sixth embodiment.

In the sixth embodiment, the shape of the casing3has been changed. As shown inFIG. 11, the seat member4has major surfaces40aand40bon both sides thereof with an interposition of the coolant channel5. Different electronic parts2cand2dare mounted on the major surfaces40aand40b, respectively.

The electronic part2cmounted on the major surface40aof the seat member4configures a switching circuit13a. Meanwhile, the electronic part2dmounted on the major surface40bof the seat member4configures another switching circuit13b.

The remaining configuration is similar to the first embodiment.

The advantages and effects of the sixth embodiment are described.

With the configuration of the sixth embodiment, the two switching circuits13aand13bare configured within a single casing3. Further, the electronic parts2cand2dconfiguring the switching circuits13aand13b, respectively, are cooled by a single coolant channel5.

Thus, the number of the casings3and the number of the coolant channels5are both reduced. As a result, the number of parts of the switching power supply1is reduced to thereby realize the switching power supply1with a compact size.

Further, since no stopper of the coolant channel is provided on the surface where the electronic parts are mounted, the coolant is prevented from flowing onto the surface of mounting the electronic parts.

Otherwise, the coolant would flow onto the surface of mounting the electronic parts in the event the coolant has leaked from a sealing portion between the stopper and the casing. Thus, the coolant will flow out of the switching power supply in the event of such leakage without flowing onto the surface of mounting the electronic parts.

Therefore, breakage or the like of the electronic parts would not be caused in the switching power supply.

Referring toFIGS. 12 to 14, a seventh embodiment of the present disclosure is described.FIG. 12is a plan view illustrating the switching power supply1according to the seventh embodiment.FIG. 13is a vertical cross-sectional view taken along a C-C line ofFIG. 12.FIG. 14is a vertical cross-sectional view taken along a D-D line ofFIG. 12.

In the seventh embodiment, the shapes of the casing3and the primary channel50have been changed. As shown inFIGS. 12 and 13, a recess300is formed in an area where the electronic parts2are mounted.

As shown inFIG. 14, the primary channel50has a semi-circular cross section perpendicular to the direction in which the coolant flows. Specifically, the primary channel50has a flat face500aon the side near the electronic parts2and an arcuate face500bon the side opposite to the flat face500a.

Thus, the casing3has a reduced thickness d between the electronic parts2and the primary channel50. At the same time, the area of cooling is enlarged, in which area the electronic parts2are mounted, to thereby enhance heat dissipation of the electronic parts2.

Further, owing to the formation of the recess300, the space in the casing3can be efficiently used and thus the size of the switching power supply1is reduced. Although the cross-sectional shape of the primary channel50in the present embodiment is semi-circular, a different shape may be used, depending such as on the constraints imposed by heat-generating parts or other parts.

The remaining configuration is similar to the first embodiment.

Various embodiments of the present disclosure have been described above. As will be understood from the description provided above, the present disclosure brings about the advantages as set forth below.

In the present disclosure, a seat member and a casing are integrally formed, with a coolant channel being formed through the seat member. Thus, the number of parts is reduced in forming the coolant channel and the size of the casing is also reduced.

Specifically, taking the case, as a comparison, where the casing92(seeFIG. 16) and the channel cover94are assembled to form a coolant channel, the channel cover94and the bolts for fixing the channel cover to the casing92are not necessary in the present disclosure. Thus, the number of parts is reduced in the present disclosure.

Further, the female thread portions for screwing the bolts are not also necessary in the present disclosure. Thus, the size of the casing is reduced in the present disclosure.

Furthermore, the coolant channel is formed through the seat member that is integrated with the casing. Therefore, the casing has a smooth outline without a concavo-convex surface. Such a shape of the casing contributes to enhancing the degree of freedom in installing the switching power supply.

Also, additional members are not required to be assembled in forming the coolant channel. Specifically, for example, the step of connecting the channel cover94to the casing92(seeFIG. 16) can be omitted. Thus, the number of steps can be reduced in manufacturing the switching power supply.

It is favorable that the casing and the seat member are integrally formed by casting. Use of casting enables integrally manufacturing the casing and the seat member as well as the coolant channel, whereby the number of parts is reduced and the configuration is simplified.

As described above, according to the switching power supply of the present disclosure, the size, the number of parts and the number of steps of manufacture are all reduced.