The present invention relates to a power converter.
In order to improve durability against an external force input to a coolant introduction pipe and a coolant discharge pipe to introduce coolant from outside or discharge the coolant in a cooler provided with a power converter, JP2014-225938A has disclosed a structure in which the coolant introduction pipe and the coolant discharge pipe are coupled to one another with a coupling plate and are fastened with bolts at a plurality of parts to a case covering the cooler via clamps.
However, since the coolant introduction pipe and the coolant discharge pipe are fixed to the case using the coupling plate and the clamps in the above-described power converter, a space required to dispose the power converter in the case increases, thereby increasing a size of the entire case. Additionally, each of the coupling plate, the clamps, and the case need to have a strength enduring an external force. Therefore, expensive members having these strengths are required and this results in a cost increase.
Further, the above-described power converter improves the durability by dispersing the external force input to the coolant introduction pipe and the coolant discharge pipe into the entire cooler including the case via, for example, the clamps. In view of this, in a case where the input external force is large, not only the coolant introduction pipe and the coolant discharge pipe but also the cooler main body is possibility damaged.
An object of the present invention is to provide a technique that ensures avoiding a cooler main body to be damaged without a need for a member, such as a coupling plate and a clamp, even in a case where an external force input to a coolant introduction pipe and a coolant discharge pipe is large.
A power converter according to one aspect of the present invention includes a power converter circuit, a cooler, and a cover member. The power converter circuit is configured to convert the input electric power into DC power or AC power. The power converter circuit is placed on the cooler. The cooler is configured to cool the power converter. The power converter circuit is housed between the cooler and the cover member. The cooler includes a main body, a coolant flow passage, and a coolant input/output portion. The coolant flow passage is formed inside the main body. A coolant is circulatable through the coolant flow passage. The coolant input/output portion is coupled to the coolant flow passage. The coolant input/output portion includes a coolant introduction pipe and a coolant discharge pipe. The coolant introduction pipe introduces the coolant from outside the cooler. The coolant discharge pipe discharges the coolant to outside the cooler. The coolant input/output portion is joined to the main body. The joined part has a joining strength lower than a strength of the main body.
The following describes the embodiments of the present invention in detail with accompanying drawings.
The power converter 100 includes a power converter circuit 1, a cooler 2, and a cover 3. The power converter 100 is, for example, mounted to a vehicle including a motor and functions as an in-car power converter as electric power supply means for this motor.
The power converter circuit 1 is an electric circuit, for example, an inverter that converts input electric power into predetermined electric power and outputs the predetermined electric power. The power converter circuit 1 is constituted of, for example, a semiconductor module and a smoothing capacitor. The power converter circuit 1 is electrically coupled to an external power supply via an electrical terminal (input terminal) (not illustrated) and coupled to the motor (not illustrated) via another electrical terminal (output terminal). The power converter circuit 1 converts DC power supplied from the above-described external power supply into AC power and supplies the AC power to the motor or converts AC power supplied from the motor into DC power and supplies the DC power to the external power supply. Further, the power converter circuit 1 of this embodiment is placed on one surface (upper surface) of the cooler 2 and is fixed to the cooler 2 with, for example, a fixing bolt (not illustrated).
The cooler 2 cools the power converter circuit 1. The cooler 2 includes a coolant flow passage 21 (see
The cover 3 functions as a housing that houses at least the power converter circuit 1 disposed on the cooler 2. The cover 3 of this embodiment has a depressed portion and is fixed to the upper surface of the cooler 2 using a fixing bolt (not illustrated) or the like such that the power converter circuit 1 is housed in this depressed portion. That is, in the power converter 100 of this embodiment, the cover 3 and the cooler 2 function as the housing that houses the power converter circuit 1. That is, the cooler 2 may be configured to double as a function as a part of the housing that houses the power converter circuit 1, in addition to the above-described cooling function. It should be noted that, the cover 3 may be configured to cover the lower surface side, not only the upper surface of the cooler 2. In this case, the cover 3 functions as the housing that houses both the power converter circuit 1 and the cooler 2. Although not illustrated, the cover 3 has a hole portion to pass through a power line coupling the power converter circuit 1 and the external power supply or the like in a state of being fixed to the cooler 2.
As illustrated in
Additionally, the coolant input/output portion 22 includes the coolant introduction pipe 22a, the coolant discharge pipe 22b, and a supporting portion 22c. The coolant introduction pipe 22a introduces the coolant from outside the cooler 2 to the coolant flow passage 21. The coolant discharge pipe 22b discharges the coolant inside the coolant flow passage 21 to outside the cooler 2. The supporting portion 22c supports the coolant introduction pipe 22a and the coolant discharge pipe 22b. That is, the coolant input/output portion 22 is coupled to the coolant flow passage 21 and has a function to exchange the coolant between outside the cooler 2 and the coolant flow passage 21.
The power converter 100 assuming the above-described configuration further includes the following features. That is, with the power converter 100 of this embodiment, a joining strength of the part (sealed portion) where the main body 20 and the coolant input/output portion 22 constituting the cooler 2 is joined together is configured lower than a strength of the main body 20.
Specifically, for example, with the main body 20 and the coolant input/output portion 22 made of metal, the sealed portions are joined by bolt fastening using a bolt made of a material having a strength lower than at least a strength of the metal forming the main body 20. Alternatively, instead of the bolt fastening, the sealed portions are joined by joining technique, such as welding and brazing, in which the joining strength is configured to be lower than at least the strength of the metal forming the main body 20.
Alternatively, with the main body 20 and the coolant input/output portion 22 made of resin, the sealed portions are joined by bolt fastening using a bolt made of a material having a strength lower than at least a strength of the resin forming the main body 20. Alternatively, instead of the bolt fastening, the sealed portions are joined by joining technique, such as welding, in which the joining strength is configured to be lower than at least the strength of the resin forming the main body 20.
Alternatively, in a case where the main body 20 and the coolant input/output portion 22 are made of different kinds of materials, such as the main body 20 being made of metal and the coolant input/output portion 22 being made of resin, the joining is performed by bolt fastening using a bolt made of a material having a strength lower than at least a strength of the material forming the main body 20 or by joining technique, such as joining of different kinds of materials, in which the joining strength is configured to be lower than at least a strength of the material forming the main body 20. It should be noted that, formation of at least one of the main body 20 and the coolant input/output portion 22 with resin allows weight reduction and low cost compared with formation of these portions with metal. The coolant input/output portion 22 may have the strength configured lower than the joining strength of the sealed portions. In this case, when an external force is input to the coolant input/output portion 22, the coolant input/output portion 22 deforms to ensure reducing stress acting on the sealed portions.
As exemplified above, in the coolant input/output portion 22 of this embodiment, the joining strength of the joined part (sealed portion) with the main body 20 is configured lower than at least the strength of the main body 20. The following describes effects obtained by the coolant input/output portion 22 of this embodiment thus configured with reference to
At this time, since the joining strength of the sealed portions is lower than the strength of the main body 20 in the power converter 100 of the present embodiment, the joining of the sealed portions is released against this external force before the main body 20 is damaged. For example, in the case where the sealed portions are joined by bolt fastening, due to a breakage of the bolt, such as a fracture of the bolt, the joining of the sealed portions is released. For example, in the case where the sealed portions are joined by welding, deposition, or the like, due to a breakage of these joined parts caused by, for example, separation and peeling, the joining of the sealed portions is released.
That is, in the present embodiment, the parts (sealed portions) having the low strength is purposely configured in the power converter 100, thus determining the sealed portion as the broken part due to the external force. Consequently, when the external force is input to the coolant input/output portion 22, the coolant input/output portion 22 is displaced according to this external force. This allows reducing this external force reaching a part other than the sealed portion of the main body 20. As a result, damage of the main body 20 in the cooler 2 due to the external force can be avoided.
Additionally, even when the influence from the external force causes a leakage of the coolant in the coolant flow passage 21, the broken part due to the external force is determined to be the sealed portion. Therefore, a direction in which the coolant leaks can be limited to downward in the gravity direction (a direction to the lower surface side of the cooler 2). Therefore, a failure of the power converter circuit 1 caused by adhesion of leaked coolant to the power converter circuit 1, which is placed on the upper surface of the cooler 2, can be avoided. Further, when the external force acts on the power converter 100, the coolant input/output portion 22 is displaced according to this external force to ensure avoiding the influence from this external force to reach the power converter circuit 1 placed on the main body 20. Accordingly, a possibility of damage of the power converter circuit 1 due to this external force can be reduced.
As described above, the in-car power converter 100 of the present embodiment includes the power converter circuit 1, the cooler 2, and the cover member 3. The power converter circuit 1 is configured to convert the input electric power into DC power or AC power. The power converter circuit 1 is placed on the cooler 2. The cooler 2 is configured to cool the power converter 1. The power converter circuit 1 is housed between the cooler 2 and the cover member 3. The cooler 2 includes the main body 20, the coolant flow passage 21, and the coolant input/output portion 22. The coolant flow passage 21 is formed inside the main body 20. The coolant is circulatable through the coolant flow passage 21. The coolant input/output portion 22 is coupled to the coolant flow passage 21. The coolant input/output portion 22 includes the coolant introduction pipe 22a and the coolant discharge pipe 22b. The coolant introduction pipe 22a introduces the coolant from outside the cooler 2. The coolant discharge pipe 22b discharges the coolant to outside the cooler 2. The coolant input/output portion 22 is joined to the main body 20. The joined part (sealed portions) has the joining strength lower than the strength of the main body 20.
The in-car power converter 100 of the present embodiment includes the power converter circuit 1, the cooler 2, and the cover member 3. The power converter circuit 1 is configured to convert the input electric power into DC power or AC power. The power converter circuit 1 is placed on the cooler 2. The cooler 2 is configured to cool the power converter 1. The power converter circuit 1 is housed between the cooler 2 and the cover member 3. The cooler 2 includes the main body 20, the coolant flow passage 21, and the coolant input/output portion 22. The coolant flow passage 21 is formed inside the main body 20. The coolant is circulatable through the coolant flow passage 21. The coolant input/output portion 22 is coupled to the coolant flow passage 21. The coolant input/output portion 22 includes the coolant introduction pipe 22a and the coolant discharge pipe 22b. The coolant introduction pipe 22a introduces the coolant from outside the cooler 2. The coolant discharge pipe 22b discharges the coolant to outside the cooler 2. The coolant input/output portion 22 is joined to the main body 20. The joined parts (sealed portions) between the coolant input/output portion 22 and the main body 20 are broken prior to the main body 20 when the external force is input to the coolant input/output portion 22.
Accordingly, when the external force is input to the power converter 100, the broken part due to this external force can be determined to be the sealed portion. Therefore, the displacement of the coolant input/output portion 22 according to this external force allows avoiding the main body of the cooler 2 to be damaged. Consequently, damage or a failure of the power converter circuit 1, which is placed on the upper surface of the cooler 2, due to the external force input to the power converter 100 can be avoided.
Additionally, with the power converter 100 of the first embodiment, the coolant input/output portion 22 is joined to the main body 20 such that at least the distal end portions of the coolant introduction pipe 22a and the coolant discharge pipe 22b project in the surface direction of the main body. This facilitates inputting the external force input from outside the cooler 2 to the coolant introduction pipe 22a and the coolant discharge pipe 22b prior to the main body 20, thereby further ensuring reducing a possibility of the external force acting on the main body 20.
With the power converter 100 of the first embodiment, the power converter circuit 1 is placed on the upper surface of the main body 20. The coolant input/output portion 22 is joined to the lower surface of the main body 20. This allows limiting the direction in which the coolant leaks to downward in the gravity direction (the direction to the lower surface side of the cooler 2). Therefore, the adhesion of leaked coolant to the power converter circuit 1, which is placed on the upper surface of the cooler 2, can be avoided.
With the power converter 100 of the first embodiment, at least one of the main body 20 and the coolant input/output portion 22 is made of resin. This formation allows weight reduction and low cost compared with the formation of the main body 20 and the coolant input/output portion 22 with metal.
The following describes a power converter 200 of the second embodiment. The power converter 200 differs from that of the first embodiment in that a reinforcing member 5 is further provided. The reinforcing member 5 is configured as a member to reduce stress especially acting on the sealed portion when the external force is input to the coolant input/output portion 22. The following describes the reinforcing member 5.
As illustrated in
The clearances A and B may be appropriately configured. In the present embodiment, configuring the clearance A allows restricting the displacement or the deformation of the coolant introduction pipe 22a and the coolant discharge pipe 22b mainly in the thickness direction when the external force is input to the coolant input/output portion with the clearance A. Moreover, configuring the clearance B allows restricting the displacement of the coolant introduction pipe 22a and the coolant discharge pipe 22b mainly in the surface direction when the external force is input to the coolant input/output portion with the clearance B. Thus, the reinforcing member 5 allows reducing the displacement of the coolant input/output portion 22 caused by the external force within a predetermined range. Accordingly, a possibility of a breakage of the sealed portion can be reduced and durability of the entire cooler 2 can be improved. As a result, the strength of the cooler 2 can be configured to be lower than that of the conventional one, ensuring achieving low cost and reduction in size. It should be noted that, the clearance A may be configured to be approximately 0 such that the reinforcing member 5 and the lower surface of the coolant input/output portion 22 nearly contact.
Meanwhile, the clearance B is not narrowed down like the clearance A but may be configured as follows. That is, as illustrated in
Additionally, the reinforcing member 5 of the present embodiment may be configured to double as a function (electromagnetic shielding function) that blocks an influence from an electromagnetic wave possibly generated in a vehicle to the power converter 200. Specifically, the reinforcing member 5 may be made of a material having a conductive property and grounded to a vehicle body (electrically conducted to GND of the vehicle). This ensures improving the durability of the cooler 2 and configuring the power converter 200 including the reinforcing member 5 having the electromagnetic shielding function. This eliminates the need for separately preparing a member having an electromagnetic shielding function and allows configuring the power converter 200 having the electromagnetic shielding function at a price lower than the conventional one. It should be noted that, without taking the improvement of the durability of the cooler 2 into consideration, the reinforcing member 5 may be made of a material at a low price further (for example, a press-worked thin walled metal plate). In that case, the reinforcing member 5 may be configured into the power converter 200 as a member independently having the electromagnetic shielding function, not the member to improve the durability of the cooler 2.
As described above, with the power converter 200 of the second embodiment, the cooler 2 includes the reinforcing member 5. The reinforcing member 5 covers at least a part of the coolant input/output portion 22. The reinforcing member 5 is the plate-shaped member. Thus, the displacement of the coolant input/output portion 22 against the external force input to the coolant input/output portion 22 can be reduced and a possibility of a breakage of the sealed portion can be reduced. As a result, the durability of the entire cooler 2 can be improved.
With the power converter 200 of the second embodiment, the reinforcing member 5 has the conductive property and is grounded to the vehicle body. Accordingly, the reinforcing member 5 can double as the electromagnetic shielding function, thereby eliminating the need for separately preparing the member having the electromagnetic shielding function. Consequently, the power converter 200 having the electromagnetic shielding function can be configured at a price lower than the conventional one.
With the power converter 200 of the second embodiment, between the coolant input/output portion 22 and the reinforcing member 5, the predetermined clearances (clearances A and B) are provided in the surface direction of the cooler 2 and the direction perpendicular to the surface direction. Thus, the reinforcing member 5 allows reducing the displacement of the coolant input/output portion 22 caused by the external force within the predetermined range (clearances A and B). Accordingly, a possibility of a breakage of the sealed portion can be reduced and durability of the entire cooler 2 can be improved.
The following describes a power converter 300 of the third embodiment. The power converter 300 differs from that of the second embodiment in an aspect of the reinforcing member 5. The power converter 300 of the present embodiment features that a part of a motor housing 7 housing a motor 6 mounted to a vehicle is utilized as the reinforcing member 5, instead of the reinforcing member 5 as the plate-shaped member in the second embodiment.
Accordingly, regarding a layout of the vehicle body, since the power converter 300 and the motor housing 7 can be disposed to be close further, a space for mounting the power converter 300 to the vehicle can be further decreased. The motor housing 7 doubling as the function of the reinforcing member 5 eliminates the need for separately disposing the reinforcing member as the plate-shaped member as in the second embodiment, ensuring achieving a low cost. It should be noted that, a relative arrangement between the cooler 2 and the motor housing 7 and a shape of the upper surface of the motor housing 7 are preferably configured providing the predetermined clearance (clearance A) according to the shape of the lower surface of the coolant input/output portion 22 as illustrated in the drawings. As illustrated in the drawings, the power converter 300 may separately include a plate-shaped member 8 covering a part other than the part covered by the motor housing 7 in the lower surface of the cooler 2. In this case, the motor housing 7 and the plate-shaped member 8 have the function of the reinforcing member 5 covering the entire lower surface of the cooler 2.
Accordingly, since the power converter 300 and the motor housing 7 can be disposed to be close further, a space for mounting the power converter 300 to the vehicle can be further decreased. The motor housing 7 doubling as the function of the reinforcing member 5 eliminates the need for separately disposing the reinforcing member as the plate-shaped member as in the second embodiment, thus ensuring achieving cost reduction. It should be noted that, a relative arrangement between the cooler 2 and the motor housing 7 and a shape of the upper surface of the motor housing 7 are preferably configured providing the predetermined clearances (the clearance A and the clearance B) from the shape of the lower surface of the cooler 2 as illustrated in the drawings.
It should be noted that, the cooler 2 and the motor housing 7 provided with the power converter 300 only need to maintain the above-described relative arrangement in the vehicle body, and the cooler 2 and the motor housing 7 are not necessary to be directly joined. The above-described relative arrangement can be achieved by, for example, fixing each of the cooler 2 and the motor housing 7 to a part of the vehicle body (not illustrated).
As described above, with the power converter 300 of the third embodiment, the cooler 2 is disposed above the motor 6 provided with the vehicle and the reinforcing member 5 is a part of the motor housing 7 that houses the motor 6. Accordingly, regarding a layout of the vehicle body, since the power converter 300 and the motor housing 7 can be disposed to be close further, a space for mounting the power converter 300 to the vehicle can be further decreased. The motor housing 7 doubling as the function of the reinforcing member 5 eliminates the need for separately disposing the reinforcing member as the plate-shaped member as in the second embodiment, ensuring achieving a low cost further.
The following describes a power converter 400 of the fourth embodiment. The power converter 400 especially features a material forming the cover 3 and provision of a rule on the relative arrangement between the cover 3 and the motor housing 7, in addition to the configuration of the power converter 300.
The cover 3 of the present embodiment has the conductive property and is grounded to the vehicle body. The motor housing 7 also has the conductive property and is grounded to the vehicle body. A predetermined clearance c is provided between the lower surface of the cover 3 and the upper surface of the motor housing 7. As the predetermined clearance c, a length shorter than a wavelength of an electromagnetic wave possibly generated in the vehicle, that is, an electromagnetic wave possibly input to the power converter 400 is configured. The cover 3 and the motor housing 7 thus configured allow the cover 3 and the motor housing 7 to have the electromagnetic shielding function for the power converter circuit 1 housed inside. This eliminates the need for separately including a member having the electromagnetic shielding function. Therefore, while the power converter 400 has the electromagnetic shielding function, downsizing and low cost can be further achieved compared with the conventional one. It should be noted that the relative arrangement between the cover 3 and the motor housing 7 in the surface direction may be appropriately configured and is not specifically limited.
As described above, with the power converter 400 of the fourth embodiment, the cover member 3 and the motor housing 6 have the conductive property and are grounded to the vehicle body. The clearance c shorter than the wavelength of the electromagnetic wave possibly generated in the vehicle is provided between the cover member 3 and the motor housing 7. This eliminates the need for separately including a member having the electromagnetic shielding function. Therefore, while the power converter 400 has the electromagnetic shielding function, downsizing and low cost can be further achieved compared with the conventional one.
While the embodiments of the present invention and their modifications have been described, the embodiments and the modifications merely describe some application examples of the present invention and not a gist to limit the technical scope of the present invention to the specific configurations of the above embodiments. The above-described embodiments and their modifications can be combined appropriately within a scope not causing inconsistency.
For example, the method for joining the main body 20 and the coolant input/output portion 22 together is not limited to the exemplified methods. As long as assuming that the joining strength of the joined part (sealed portion) is lower than the strength of the main body 20, the joining method may be appropriately selected.
Moreover, the input of the external force to the coolant input/output portion 22 is not necessarily only the direct input to the coolant input/output portion 22 but also includes an indirect input via the hose or the like coupled to the coolant input/output portion 22. Additionally, the external force input to the coolant input/output portion 22 is not only caused by a collision or the like but includes a pressure or the like when the hose is coupled to the coolant input/output portion 22.
It should be noted that, the illustrated drawings in this description are merely the schematic diagrams. Accordingly, the configurations illustrated in the drawings are one example. As long as meeting the matters defined in the above-described description, the configurations and the aspects are not limited to those illustrated in the drawings. For example, the coolant introduction portion 22a and the coolant discharge portion 22b may be joined to the main body 20 without having the projecting parts in the surface direction of the main body 20. The coolant input/output portion 22 is not necessarily to be joined to the lower surface of the main body 20 but may be joined to the side surface or the upper surface of the main body 20. In the coolant input/output portion 22, the coolant introduction portion 22a and the coolant discharge portion 22b are not necessarily to be integrally configured but may be configured as two separate members.
The shape of the coolant input/output portion 22 illustrated in
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2018/009692 | 3/13/2018 | WO | 00 |