JP7143771B2 - power converter - Google Patents

Description

The present invention relates to power converters.

2. Description of the Related Art Conventionally, an electric power provided with a housing body having a housing space for housing a circuit board and a through hole formed in a side wall, and a closing member for blocking the opening of the through hole on the outer surface of the side wall of the housing. Conversion devices are known. Such a power converter is arranged, for example, in an engine room of a vehicle. When liquid such as rainwater or salt water adheres to the housing, the liquid flows downward in the direction of gravity along the housing, and enters the housing space through the gap between the outer surface of the side wall of the housing and the closing member. There is a risk of intrusion.

The power conversion device disclosed in Patent Literature 1 includes a protruding portion that protrudes from the outer surface of the side wall of the housing. The projecting portion is arranged above the connector, which is the closing member, in the direction of gravity. In this case, since the liquid adhering to the housing accumulates on the upper surface of the projecting portion, the liquid is prevented from entering the accommodation space through the gap between the side wall of the housing and the closing member.

JP 2017-79547 A

However, depending on the amount of the liquid, it may overflow the upper surface of the protrusion without being completely collected, and flow downward in the gravity direction from the protrusion along the tip surface of the protrusion. The liquid that has flowed out flows into the gap between the lower surface of the projecting portion and the upper surface of the closing member, and further enters the gap between the side wall of the housing and the closing member.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a power converter capable of suppressing liquid from entering a gap between a housing and a closing member.

A power conversion device for solving the above problems includes a housing having a housing space for housing a circuit board and a through hole formed in a side wall, and an opening of the through hole on the outer surface of the side wall of the housing. and a protrusion projecting from the outer surface of the side wall of the housing and positioned above the closing member in the gravitational direction, wherein the side wall of the housing and is located between the opening of the through hole and the protrusion in the direction of gravity, and the closing member covers a part of the opening of the groove in the direction of gravity. an upper surface of the closing member located above the gravitational direction is located above a lower inner surface of the groove located below the gravitational direction in the gravitational direction; The gist is to have an inner surface that closes the opening of the through-hole, extends continuously to the upper surface, and covers a part of the opening of the groove .

For example, when the gap between the protrusion and the blocking member directly communicates with the gap between the side wall of the housing and the blocking member, the liquid accumulated in the gap between the protrusion and the blocking member is transferred to the gap between the side wall of the housing and the blocking member. Since the liquid touches the gap, it is easy for the liquid to enter the gap between the side wall of the housing and the closing member.

On the other hand, a groove is formed in the outer surface of the side wall of the housing, and a part of the opening of the groove is covered with the blocking member, so that the gap between the projecting portion and the blocking member is reduced to the groove. It communicates with the gap between the side wall of the housing and the closing member via the space surrounded by the closing member. For this reason, droplets collected in the gap between the projecting portion and the closing member do not touch the gap between the side wall of the housing and the closing member. Therefore, it is possible to prevent the liquid remaining in the gap between the projecting portion and the closing member from entering the gap between the side wall of the housing and the closing member.

Further, in the above power conversion device, it is preferable that a sealing member arranged so as to surround the through-hole is interposed between the outer surface of the side wall of the housing and the closing member.
By arranging the sealing member between the side wall of the housing and the closing member, it is possible to prevent liquid from entering the storage space through the gap between the side wall of the housing and the closing member. However, if the liquid that has entered between the side wall of the housing and the closing member is salt water, the salt water may corrode the sealing member and degrade the sealing function. Therefore, it is effective to suppress the intrusion of the liquid into the gap between the side wall of the housing and the closing member, thereby suppressing the deterioration of the sealing function of the sealing member.

Further, in the above power converter, it is preferable that the amount of protrusion of the closing member from the outer surface of the side wall of the housing is larger than the amount of protrusion of the protrusion from the outer surface of the side wall of the housing.
According to this, compared with the case where the amount of protrusion of the closing member from the outer surface of the side wall of the housing is smaller than the amount of protrusion of the protrusion from the outer surface of the side wall of the housing, it is possible to reduce the size of the power converter. Further, in a configuration in which the amount of protrusion of the closing member from the outer surface of the side wall of the housing is larger than the amount of protrusion of the protrusion from the outer surface of the side wall of the housing, the closing member acts like a tray for the liquid overflowing from the protrusion. Therefore, liquid droplets are likely to enter the gap between the projecting portion and the closing member. Therefore, it is more effective to prevent droplets from entering the gap between the housing and the closing member.

According to the present invention, droplets can be prevented from entering the gap between the side wall of the housing and the closing member.

The perspective view of a power converter device. 1 is an exploded perspective view of a power conversion device; FIG. Sectional drawing of a power converter device. FIG. 4 is a partial cross-sectional view for explaining the operation of the embodiment; (a), (b) is a partial sectional view which shows the comparative example of a power converter device. Sectional drawing which shows another example of a power converter device. Sectional drawing which shows another example of a power converter device.

An embodiment embodying a power conversion device will be described below with reference to FIGS. 1 to 4. FIG. In the drawings, the horizontal plane is defined by orthogonal X and Y directions, and the direction along the direction of gravity is defined by the Z direction.

As shown in FIGS. 1 and 2, the power converter 10 is an in-vehicle inverter that receives DC power from an in-vehicle battery or the like, converts it into AC power, and outputs the AC power to an in-vehicle device such as a motor. The power conversion device 10 includes a circuit board 11 having an inverter circuit as a power conversion circuit, and a housing 12 that accommodates the circuit board 11 . It should be noted that the illustration of a connector that connects the vehicle-mounted battery or the like and the power conversion device 10 and a connector that connects the power conversion device 10 and the motor or the like is omitted. The power conversion device 10 is arranged, for example, in an engine room of a vehicle (not shown), and the housing 12 is exposed to the usage environment of the vehicle.

The inverter circuit provided on the circuit board 11 includes a control circuit, a semiconductor element, a smoothing capacitor, a drive circuit (all not shown), and the like. Input DC power is converted into AC power by turning on/off the semiconductor element through the control circuit/driving circuit, and the AC power is output.

The housing 12 includes a housing main body 21 in the shape of a square cylinder with a bottom, and a rectangular lid 22 that closes an opening 21 a of the housing main body 21 . The housing main body 21 has a rectangular bottom wall 21b and first to fourth wall portions 21c to 21f as side walls erected from respective edges of the bottom wall 21b. The longitudinal direction of the bottom wall 21b and the lid 22 extends in the X direction, and the lateral direction of the bottom wall 21b and the lid 22 extends in the Y direction. The first wall portion 21c stands from one of the pair of short edges of the bottom wall 21b, and the second wall portion 21d stands from the other of the pair of short edges of the bottom wall 21b. Stand from the short edge. Further, the third wall portion 21e stands from one long edge portion of the pair of long edge portions of the bottom wall 21b, and the fourth wall portion 21f stands from the pair of long edge portions of the bottom wall 21b. Stand from the other long edge. The housing 12 includes a housing space S surrounded by a bottom wall 21b, first to fourth walls 21c to 21f, and a lid 22. As shown in FIG. The circuit board 11 is housed in the housing space S. As shown in FIG. Further, the housing main body 21 and the lid 22 are stacked in the Z direction, the lid 22 is positioned on the upper side in the Z direction, and the housing main body 21 is positioned on the lower side in the Z direction.

As shown in FIGS. 2 and 3, the housing body 21 is formed with a through hole 23 penetrating through the first wall 21c in the X direction. The through-hole 23 of this embodiment has an elliptical shape with a long axis extending in the Y direction and a short axis extending in the Z direction. The housing space S and the outside of the housing 12 are communicated with each other through the through hole 23 . The through hole 23 has an opening 23a that opens on the outer surface of the first wall 21c of the housing main body 21 . Further, the first wall portion 21c has first mounting holes 24 formed on both sides of the through hole 23 in the Y direction. A female thread is formed on the inner peripheral surface of each first mounting hole 24 .

The housing 12 has a protruding portion 25 protruding in the X direction from the outer surface of the first wall portion 21c. The projecting portion 25 has a quadrangular prism shape extending in the Y direction. The length of the protrusion 25 in the Y direction is longer than the longitudinal dimension of the through hole 23 . The projecting portion 25 is positioned above the opening 23 a of the through hole 23 in the Z direction. In the projecting portion 25, the surface along the YZ plane is defined as a tip surface 25a, the surface along the XY plane and located near the lid 22 in the Z direction is defined as an upper surface 25b, and the surface along the XY plane and Z Let the surface located in the through-hole 23 side|approaching|deviation in a direction be the lower surface 25c. The distance from the outer surface of the first wall portion 21c to the tip surface 25a of the projecting portion 25 is defined as a projection amount L1 of the projecting portion 25 from the outer surface of the first wall portion 21c.

The housing 12 has a groove 26 recessed in the X direction from the outer surface of the first wall portion 21c. The groove 26 extends in the Y direction. The length of the groove 26 in the Y direction is the same as the length of the protrusion 25 in the Y direction. The groove 26 has a bottom 26a along the YZ plane. A dimension P from the outer surface of the first wall portion 21c to the bottom portion 26a in the X direction is set to 1 mm, for example. Further, the groove 26 connects the bottom portion 26a and the outer surface of the first wall portion 21c in the X direction, and also connects the upper inner side surface 26b located on the upper side in the Z direction and the bottom portion 26a and the outer surface of the first wall portion 21c. It has a lower inner side surface 26c that is connected in the X direction and located on the lower side in the Z direction. The upper inner surface 26b is flush with the lower surface 25c of the projecting portion 25. As shown in FIG. The groove 26 has an opening 26d that opens on the outer surface of the first wall portion 21c of the housing main body portion 21 .

The housing 12 includes a plate-like closing member 27 that blocks the opening 23a of the through hole 23 from the outside of the housing 12 . The blocking member 27 has a rectangular shape with a longitudinal direction extending in the Y direction and a lateral direction extending in the Z direction. The lengthwise and widthwise dimensions of the closing member 27 are respectively greater than the lengthwise and widthwise dimensions of the through hole 23 . The closing member 27 is formed with two second mounting holes 28 that pass through in the X direction and are spaced apart in the Y direction. The interval between the two second mounting holes 28 is the same as the interval between the two first mounting holes 24 .

The closing member 27 is attached to the first wall portion 21c of the housing main body 21 by screwing the bolt 13 inserted through the second mounting hole 28 into the first mounting hole 24 of the housing main body 21. . In the closing member 27, the upper surface in the gravitational direction is the upper surface 27a, the surface facing the first wall portion 21c is the inner surface 27b, and the surface opposite to the inner surface 27b is the outer surface 27c. The upper surface 27a of the closing member 27 is located above the lower inner side surface 26c of the groove 26 in the Z direction. In other words, the closing member 27 covers a part of the opening 26d of the groove 26 on the lower side in the Z direction. A dimension Q from the upper surface 27a of the closing member 27 to the lower surface 25c of the projecting portion 25 is set to 0.5 mm, for example. Also, the distance from the outer surface of the first wall portion 21c to the outer surface 27c of the closing member 27 is defined as a protrusion amount L2 of the closing member 27 from the outer surface of the first wall portion 21c. A protrusion amount L2 of the blocking member 27 is larger than a protrusion amount L1 of the protruding portion 25 . Therefore, the outer surface 27c of the closing member 27, the tip surface 25a of the projecting portion 25, and the outer surface of the first wall portion 21c are arranged in this order in the X direction.

Between the outer surface of the first wall portion 21c of the housing main body portion 21 and the inner surface 27b of the closing member 27, an elliptical seal ring 14 is interposed as a sealing member. The seal ring 14 is arranged to surround the opening 23a of the through hole 23 of the first wall portion 21c. The seal ring 14 seals the gap between the outer surface of the first wall portion 21c of the housing main body 21 and the inner surface 27b of the closing member 27, thereby preventing salt water from entering the housing space S from the outside of the housing 12. suppress

The operation of this embodiment will be described in comparison with the comparative example shown in FIGS. 5(a) and 5(b).
When the salt water W adheres to the housing 12 , the salt water W first accumulates on the upper surface 25 b of the projecting portion 25 . However, when the amount of salt water W increases, it overflows without remaining on the upper surface 25b of the protruding portion 25 . The overflowing salt water W flows along the tip surface 25 a of the projecting portion 25 to the lower side in the Z direction than the projecting portion 25 and flows into the gap between the lower surface 25 c of the projecting portion 25 and the upper surface 27 a of the blocking member 27 .

Here, as shown in FIG. 4, in this embodiment, the gap between the lower surface 25c of the protruding portion 25 and the upper surface 27a of the closing member 27 is formed through the space surrounded by the groove 26 and the inner surface 27b of the closing member 27. , and communicates with the gap between the outer surface of the first wall portion 21 c and the inner surface 27 b of the closing member 27 . Therefore, the salt water W accumulated in the gap between the lower surface 25c of the projecting portion 25 and the upper surface 27a of the closing member 27 does not directly contact the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27. Therefore, the entry of salt water W into the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27 is suppressed. The salt water W remaining in the gap between the lower surface 25c of the projecting portion 25 and the upper surface 27a of the closing member 27 does not flow into the groove 26 due to surface tension and remains in the gap.

As a comparative example, FIG. 5A shows the case where the groove 26 is not formed on the outer surface of the first wall portion 21c, and FIG. 5B shows the case where the groove 26 is formed on the outer surface of the first wall portion 21c. 4 shows a case where the closing member 27 does not cover the opening 26d of the groove 26, although the opening 26d of the groove 26 is covered. In each comparative example, the gap between the lower surface 25c of the projecting portion 25 and the upper surface 27a of the closing member 27 directly communicates with the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27. Therefore, the salt water W accumulated in the gap between the lower surface 25c of the projecting portion 25 and the upper surface 27a of the closing member 27 directly contacts the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27. Therefore, the salt water W is likely to enter the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27 .

Effects of the present embodiment will be described.
(1) The groove 26 recessed in the outer surface of the first wall portion 21c of the housing body portion 21 is located between the opening portion 23a of the through hole 23 of the first wall portion 21c and the projecting portion 25 in the Z direction, which is the direction of gravity. located between The closing member 27 covers a part of the opening 26d of the groove 26 on the lower side in the Z direction. Therefore, the salt water W accumulated in the gap between the lower surface 25c of the projecting portion 25 and the upper surface 27a of the closing member 27 does not touch the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27. Therefore, salt water W remaining in the gap between the lower surface 25c of the projecting portion 25 and the upper surface 27a of the closing member 27 can be prevented from entering the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27.

(2) Between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27, the seal ring 14 is interposed so as to surround the through hole 23. As shown in FIG. The seal ring 14 seals the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27 to prevent salt water W from entering the accommodation space S. However, the seal ring 14 may be corroded by the salt water W that has entered between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27, and the sealing function may deteriorate. Therefore, it is effective to prevent the salt water W from entering the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27, and to prevent the sealing function of the seal ring 14 from deteriorating.

(3) The protrusion amount L2 of the closing member 27 from the outer surface of the first wall portion 21c is larger than the protrusion amount L1 of the protrusion portion 25 from the outer surface of the first wall portion 21c. Therefore, compared to the case where the projection amount L2 of the closing member 27 from the outer surface of the first wall portion 21c is smaller than the projection amount L1 of the projection portion 25 from the outer surface of the first wall portion 21c, the power conversion device 10 is Can be made smaller. Further, in a configuration in which the projection amount L2 of the closing member 27 from the outer surface of the first wall portion 21c is larger than the projection amount L1 of the projection portion 25 from the outer surface of the first wall portion 21c, the upper surface 27a of the closing member 27 is It becomes like a saucer for the salt water W overflowing from the upper surface of the projecting portion 25 . For this reason, the salt water W is likely to enter the gap between the lower surface 25 c of the projecting portion 25 and the upper surface 27 a of the closing member 27 . Therefore, it is more effective to prevent the salt water W from entering the gap between the outer surface of the first wall portion 21c and the inner surface 27b of the closing member 27 .

This embodiment can be implemented with the following modifications. This embodiment and modifications can be implemented in combination with each other within a technically consistent range.
(circle) the power converter device 10 is not limited to an inverter, For example, other power converter devices, such as a DC/DC converter, may be used.

(circle) the through-hole 23 is not limited to an elliptical shape, and may be circular.
O The closing member 27 is not limited to a mere plate material, and may be, for example, a part of a connector as long as it can close the through hole 23 .

(circle) dimension P from the outer surface of the 1st wall part 21c to the bottom part 26a of the groove|channel 26 may be changed suitably, if it is 0.3 mm or more.
○ The dimension Q from the upper surface 27a of the closing member 27 to the lower surface 25c of the projecting portion 25 may be appropriately changed within the range of 0 to 3 mm. However, the upper surface 27a of the closing member 27 is located above the lower inner side surface 26c of the groove 26 in the Z direction and covers part of the opening 26d of the groove 26. As shown in FIG.

O The protrusion amount L2 of the closing member 27 from the outer surface of the first wall portion 21c may be the same as or smaller than the protrusion amount L1 of the protrusion portion 25 from the outer surface of the first wall portion 21c.
(circle) the shape of the closure member 27 may be changed suitably.

For example, as shown in FIG. 6, the closing member 27 may have a shaft portion 27d protruding from the inner surface 27b. The shaft portion 27d is inserted into the through hole 23 of the first wall portion 21c. In such a configuration, the seal ring 14 may be interposed between the outer peripheral surface of the shaft portion 27d and the inner peripheral surface of the through hole 23 of the first wall portion 21c.

(circle) the structure of the housing|casing 12 may be changed suitably.
For example, as shown in FIG. 7, the housing main body 21 may include partition walls 211 that partition the housing space S in the Z direction. Of the accommodation space S, the space positioned above the partition wall 211 in the Z direction is defined as a first accommodation space S1, and the space positioned below the partition wall 211 in the Z direction is defined as a second accommodation space S2. do. The first accommodation space S1 accommodates, for example, a first circuit board 11a having an inverter circuit, and the second accommodation space S2 accommodates, for example, a second circuit board 11b having a converter circuit. .

The housing main body 21 has a hole 29 passing through the second wall 21 d in the X direction, and a tubular flange 30 projecting from the outer surface of the second wall 21 d so as to surround the hole 29 . The inside of the flange portion 30 communicates with the hole 29 of the second wall portion 21d. A hole 211a is formed through the partition wall 211 in the X direction. One end of the hole 211a communicates with the through hole 23 of the first wall portion 21c, and the other end of the hole 211a communicates with the hole 29 of the second wall portion 21d.

6, the closing member 27 has a shaft portion 27d protruding from the inner surface 27b. The shaft portion 27d is inserted inside the through hole 23 of the first wall portion 21c. The seal ring 14 is interposed between the outer peripheral surface of the shaft portion 27d and the inner peripheral surface of the through hole 23 of the first wall portion 21c.

Further, the inside of the hole 211a of the partition wall 211, the inside of the hole 29 of the second wall portion 21d, and the inside of the flange portion 30 form a flow path R for flowing cooling water. The closing member 27 closes the through hole 23 so that the cooling water flowing through the flow path R does not flow out from the through hole 23 . The first circuit board 11a accommodated in the first accommodation space S1 and the second circuit board 11b accommodated in the second accommodation space S2 are simultaneously cooled by flowing cooling water through the flow path R. be.

O The number of bolts 13 for attaching the closing member 27 to the first wall portion 21c of the housing main body portion 21 is not limited to two, and may be changed as appropriate.

DESCRIPTION OF SYMBOLS 10... Power converter, 11... Circuit board, 12... Case, 14... Seal ring as sealing member, 21c to 21f... First to fourth wall portions as side walls, 23... Through hole, 23a... Opening, 25... Protruding portion, 26... Groove, 26d... Opening, 27... Closing member, S... Accommodating space, L1, L2... Projection amount.

Claims (3)

a housing having a housing space for housing a circuit board and having a side wall formed with a through hole;
a closing member that closes the opening of the through hole on the outer surface of the side wall of the housing;
a projecting portion projecting from the outer surface of the side wall of the housing and positioned above the closing member in the direction of gravity,
a groove recessed in the outer surface of the side wall of the housing and positioned between the opening of the through-hole and the protrusion in the direction of gravity;
The closing member covers a part of the opening of the groove in the direction of gravity,
an upper surface of the closing member located above the gravitational direction is located above a lower inner surface of the groove located below the gravitational direction;
The power conversion device, wherein the closing member has an inner surface that closes the opening of the through-hole, extends continuously to the upper surface, and partially covers the opening of the groove . 2. The power conversion device according to claim 1, wherein a sealing member arranged so as to surround said through-hole is interposed between the outer surface of the side wall of said housing and said closing member. 3. The power converter according to claim 1, wherein the amount of protrusion of the closing member from the outer surface of the side wall of the housing is larger than the amount of protrusion of the protrusion from the outer surface of the side wall of the housing.

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