Power conversion device

Abstract

A power conversion device fixedly connected to a motor housing that houses a motor includes a housing having a plurality of side walls and an opening on a motor side, a cover covering an upper surface of the housing, and a plurality of internal components housed in the housing. The plurality of internal components include a capacitor. The housing includes a connecting portion connected to the motor housing and a plurality of fixing portions fixing the capacitor to an inner side of the housing. In the housing, a first space is provided between the capacitor and the cover, and a second space is provided between the capacitor and the motor. The plurality of internal components are arranged to connect a pair of opposite side walls among the plurality of side walls.

Description

Technical area

[0001] The present invention relates to a power conversion device. State of the art

[0002] Regarding a housing shape of a power conversion device for an electric vehicle or a hybrid vehicle, for example, PTL 1 discloses a power conversion device having a structure including a bottom surface for holding components and securing strength. Citation listPatent literature

[0003] PTL 1: JP 2013-115903 A Summary of the inventionTechnical problem

[0004] Since PTL 1 requires a large projection area on a floor surface, the size of a molding machine is increased, resulting in an increase in cost. Furthermore, since the housing occupies the floor surface, the space inside or at the bottom of the housing is partitioned, and the arrangement of components is restricted. This leads to an increase in the dimension of an inverter in a height direction. Furthermore, regarding component strength, it was difficult to ensure mechanical strength because the components were conventionally mounted individually. Solution to the problem

[0005] A power conversion device fixedly connected to a motor housing that houses a motor includes a housing having a plurality of side walls and an opening on a motor side, a cover covering an upper surface of the housing, and a plurality of internal components housed in the housing. The plurality of internal components include a capacitor. The housing includes a connecting portion connected to the motor housing and a plurality of fixing portions fixing the capacitor to an inner side of the housing. In the housing, a first space is provided between the capacitor and the cover, and a second space is provided between the capacitor and the motor. The plurality of internal components are arranged to connect a pair of opposite side walls among the plurality of side walls. Advantageous effects of the invention

[0006] According to the present invention, a power conversion device can be provided that achieves cost reduction, downsizing, suppression of strength reduction, and improvement of assembling property. Short description of the drawings [ Fig. 1] Fig. 1 is an overall perspective view of a power conversion device. [ Fig. 2] Fig. 2 is an exploded view of Fig. 1 according to an embodiment of the present invention. [ Fig. 3] Fig. Figure 3 is a cross-sectional view of the device as indicated by an arrow A of Fig. 2, according to an embodiment of the present invention. [ Fig. 4] Fig. 4 is a plan view of an inverter case according to an embodiment of the present invention. [ Fig. 5] Fig. 5 is a plan view of a capacitor as viewed from an upper direction and a front view thereof as viewed from an arrow B according to an embodiment of the present invention.

[0007] An embodiment of the present invention will be described below with reference to the drawings. The following description and drawings are examples for describing the present invention and are omitted and simplified for clarity of description. The present invention may be embodied in various other modes. For each component, unless otherwise stated, a single component or a plurality of components may be provided.

[0008] Positions, sizes, shapes, areas, and the like of the components illustrated in the drawings may not represent actual positions, sizes, shapes, areas, and the like in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, areas, and the like disclosed in the drawings. (First Embodiment and Overall Configuration of the Present Invention) (FIG. 1)

[0009] The lower surface of an inverter 1 is fixed to a motor housing 2 by fasteners such as screws and is firmly connected thereto. The motor housing 2 accommodates a motor (not shown) and functions as the base of the inverter 1 because the inverter 1 is firmly connected thereto. (FIG. 2)

[0010] The inverter 1 includes a top cover 11 and an inverter housing 17. The inverter housing 17 is made of metal and has a plurality of side walls and an opening 1c. The opening is located on a motor side (side of the motor housing 2), not shown. The inverter housing 17 has a plurality of inverter components such as a capacitor 16 therein. The top cover 11 is fixed so as to cover the upper surface (upper surface in Fig. 2) of the inverter housing 17, thereby protecting the internal components within the inverter housing 17. The inverter housing 17 accommodates a low-voltage (LV) connector 12, a ground substrate 13, a power module 14, a bus bar 15, and a capacitor 16 as the internal components. Furthermore, the inverter housing 17 includes a direct current (DC) connector 18, which is a connection interface connected to external components on the outer sides of the side walls.

[0011] The LV connector 12 is a connection interface for connecting the inverter 1 to external components on the side of the top cover 11 and penetrates the top cover 11. Note that the LV connector 12 penetrates any position of the top cover 11 and may penetrate another position on the top cover 11.

[0012] The ground substrate 13 controls the inverter 1. The power module 14 converts power to be input to the inverter 1 and monitors a current. The power module 14 is integrated with a path (not shown) through which cooling water flows into the inverter 1. The busbar 15 connects the power module 14 and the motor (not shown) mounted in the motor housing 2. The capacitor 16 rectifies power input from outside the inverter 1 via the DC connector 18 and causes the rectified power to flow into the power module 14. Furthermore, the capacitor 16 reduces emission noise. The DC connector 18 is a connection interface that connects a power supply outside the inverter 1 and the inverter 1. (FIG. 3)

[0013] The inverter case 17 includes a plurality of fastening portions 17b for fastening the capacitor 16 to the inside of the inverter case 17. The capacitor 16, which has fastening portions corresponding to the plurality of fastening portions 17b, is firmly connected to the power module 14 and the inverter case 17 by aligning the fastening portions and inserting fastening members 20 such as screws therein. Furthermore, the inverter case 17 has a case fastening portion 17a on the outside and is connected to the motor case 2 by inserting a fastener or the like into the case fastening portion 17a to form a connecting portion 3. An opening 1c is formed between a space at the position of the capacitor 16 in an interior of the inverter case 17 and an interior of the motor case 2.The opening 1c will be described later with reference to . Fig. 4 described.

[0014] The inverter housing 17 has a first space 1a between the capacitor 16 and the top cover 11 and a second space 1b between the capacitor 16 and the motor housing 2 (or the motor not shown). Since the first space 1a and the second space 1b are formed in the inverter housing 17, the wiring connected to the capacitor 16 is easy to route. Furthermore, the connection between the internal components in the inverter housing 17 and the motor not shown, which is housed in the motor housing 2, is facilitated. As will be described later with reference to Fig. 4, the capacitor 16 serves as a support for the inverter housing 17 and contributes to ensuring the strength of the inverter housing 17. (FIG. 4)

[0015] The inverter housing 17 has the opening 1c. The inverter housing 17 further includes the plurality of mounting portions 17a and the plurality of mounting portions 17b. The above-described capacitor 16 is mounted in the inverter housing 17 by the capacitor mounting portions 17b.

[0016] Since the inverter housing 17 has a bottom surface, the components to be mounted within the inverter housing 17 can conventionally only be mounted from one direction. Furthermore, since the busbar to be routed within the inverter housing 17 requires a step of making a hole on the bottom surface for connection to the motor side, the manufacturing steps increase.

[0017] However, since the inverter case 17 has the opening 1c on the bottom surface as in the present invention, the internal components can be mounted from either surface of the inverter case 17. Therefore, the flexibility of the mounting order of the internal components is increased, and the space in the inverter case 17 can be effectively used for arranging the components, thereby increasing the flexibility of arranging the internal components. Furthermore, the presence of the opening 1c increases the flexibility of arranging the bus bar to be routed in the inverter case 17, thus improving spatial efficiency.

[0018] Since the opening 1c is arranged in the inverter case 17, a projection area is reduced, and molding costs and weight can be reduced. Furthermore, since the capacitor 16 is installed to align with a formation position of the opening 1c, the capacitor 16 serves as a structural member of the inverter case 17. Specifically, the capacitor 16 functions as a support of the inverter case 17 by being arranged to connect a pair of opposite side walls among the side walls of the inverter case 17. Furthermore, not only the capacitor 16 but also the above-described power module 14 is installed in the inverter case 17 at a position different from the installation position of the capacitor 16. As a result, the power module 14 functions as a support as a structural member of the inverter case 17.In this way, the strength of the inverter housing 17 can be ensured by each internal component.

[0019] The power module 14 and the capacitor 16 are mounted in the inverter case 17 to serve as supports within the inverter case 17. The value of the natural frequency varies for each element. Therefore, even if one element of the power module 14 and the capacitor 16 resonates, when resonance occurs, the other element serves as a support. As a result, vibration of the side walls of the inverter case 17 can be dampened, and deformation of the inverter case 17 can be suppressed. Thus, strength at the time of resonance can be ensured.

[0020] Regarding the plurality of fixing portions 17b included in the inverter case 17, since heavy components such as the capacitor 16 and the power module 14 need to be fixed to the inside of the inverter case 17, the strength of the fixing portions 17b themselves needs to be increased. Therefore, in order to increase the strength of the fixing portions 17b more than the strength of the side walls, the rigidity of the side walls of the inverter case 17 is made lower than the rigidity of the fixing portions 17b. Thus, the force applied to the wall surfaces of the inverter case 17 can be transmitted to the internal component side through the fixing portions 17b. Furthermore, transmission of vibration and shock to the capacitor 16 can be prevented by improving the rigidity of the fixing portions 17b.This can not only ensure the strength of the wall surfaces themselves, but also contribute to improving earthquake resistance.

[0021] Note that high mechanical strength can be ensured by a method for increasing the rigidity of the fixing portions 17b, for example, by forming the fixing portions 17b in a thick shape or a rib shape or the like formed on an outer peripheral side (side wall outer side) of the fixing portions 17b.

[0022] Furthermore, such a configuration of the fixing portions 17b also contributes to solving the problem that the strength of the inverter case 17 is reduced due to the presence of the opening 1c. Specifically, the wall surfaces of the inverter case 17, which have lower strength than the fixing portions 17b, can be made thinner. Since the inverter case 17 is elastically deformed by the presence of the opening 1c, for example, an absorption effect against vibration and shock transmitted from the motor can be achieved, and shock generated in the fixing portions 17b can also be dampened.

[0023] Furthermore, with regard to routing the busbar and wiring connected to the motor side, providing the opening 1c can also reduce the design cost because the machining accuracy related to the hole tolerance on the inverter housing 17 side does not need to be considered, and thus only the positional tolerance of the busbar is taken into account. That is, since the inverter housing 17 does not have the bottom surface, the connectivity between the internal components in the inverter housing 17 and the components arranged on the motor side is improved. This facilitates the efficiency of the space within the inverter housing 17. (FIG. 5)

[0024] Fig. 5(a) is a plan view of the capacitor 16 as viewed from the upper surface, and an explanatory view of a plurality of fixing portions 20a to 20e arranged in the capacitor 16. Fig. Fig. 5(b) is a front view of the capacitor 16 as viewed from a direction B of Fig. 5(a).

[0025] The capacitor 16 has the fastening portions 20a to 20e for fastening the capacitor to the inverter case 17. The connection between the capacitor 16 and the inverter case 17 does not necessarily need to use screws or the like. For example, bolts or the like may be set to stand on the side of the inverter case 17, and the bolts or the like may be fastened with nuts. Alternatively, a snap-in structure may be provided on the inverter case 17 or the capacitor 16, and the capacitor 16 and the inverter case 17 are fastened by fitting the snap-in structure.

[0026] A countermeasure against lateral swinging of the inverter housing 17 is described. The fixing portions 20a to 20e, which are Fig. 5(a) and Fig. 5(b) are arranged so that the distance between the fastening sections close to each other is as short as possible.

[0027] In the capacitor 16, the fixing portions 20a are fixed to each other, and the fixing portions 20b are fixed to each other. In this way, by fixing the fixing portions 20a to each other, a truss shape is formed by the pair of fixing portions 20a and a corner portion 16b of the capacitor 16. Therefore, the strength of the capacitor 16 and the inverter case 17 is ensured, and all vibration can be suppressed. Similarly, by fixing the fixing portions 20b to each other, a truss shape is formed by the pair of fixing portions 20b and a corner portion 16a of the capacitor 16. Therefore, the strength of the capacitor 16 and the inverter case 17 is ensured, and all vibration can be suppressed.

[0028] Furthermore, by fastening the fastening portion 20c, which is in Fig. As shown in Fig. 5(a), a small truss shape is formed by the fixing portion 20c, the fixing portion 20d formed in a short length direction of the capacitor 16 and located close to the fixing portion 20c, and the corner portion 16a. Therefore, vibration of the corner portion 16a of the capacitor 6 can be suppressed. Similarly, by fixing the fixing portion 20d, a small truss shape is formed by the fixing portion 20d, the fixing portion 20a formed in a short length direction of the capacitor 16 and located close to the fixing portion 20d, and the corner portion 16b. Therefore, vibration of the corner portion 16b of the capacitor 6 can be suppressed.In this way, the strength of the capacitor 16 in the inverter case 17 can be secured, the range of influence in which the internal components act as supports in the inverter case 17 can be expanded, and the strength can be further secured.

[0029] In a case where the capacitor 16 is fixed to the inverter case 17 with as few fasteners as possible, priority is given to fixing between the fixing portions 20a and between the fixing portions 20b rather than fixing between the fixing portions 20c and 20d, thereby reliably securing the strength.

[0030] Next, a countermeasure against the vertical swing of the inverter case 17 using the plurality of fixing portions 20a to 20e shown in Fig. 5(b). The plurality of fixing portions 20a to 20e includes a combination of fixing portions arranged at different positions in a thickness direction of the capacitor 16. Specifically, the combinations include three sets, including one set of fixing portions 20b arranged in Fig. 5(b) (the other is shown in Fig. 5(a)), a set of the fixing portions 20c and 20d, and a set of the fixing portions 20a and 20e. In this way, the capacitor 16 can be uniformly fixed to the inverter case 17 to have strength.

[0031] Furthermore, Fig. 5(b), a truss shape is formed by the fixing portion 20a, the fixing portion 20b, and the corner portion 16c, and two points as far apart as possible at both end portions of the capacitor 16 can be connected. As a result, a function of supporting the capacitor 6 in the inverter case 17 can be maintained, vibration resistance is improved, and an influence area acting as a support can be expanded.

[0032] In Fig. 5(b), the fixing portion 20a and the fixing portion 20c, and the fixing portion 20d, the fixing portion 20e and the fixing portion 20b can achieve the fixing that reinforces the central portion of the capacitor 6. Therefore, the strength of the capacitor 16 can be further secured.

[0033] Further, as a countermeasure against the self-vibration (countermeasure against resonance) of the inverter case 17, the plurality of fixing portions 20a to 20e includes a combination of the fixing portions 20a to 20e arranged at the same position in the thickness direction of the capacitor 16 as shown in Fig. 5(b), taking into account that a portion that vibrates slightly varies in respective vibration modes. Specifically, in the thickness direction of the capacitor 16, the fixing portions 20b are aligned at the same position, the fixing portions 20c and 20d are aligned at the same height, and the fixing portions 20a and 20e are aligned at the same height. In this way, mounting performance can be improved.

[0034] As described above, the risk of insufficient strength due to the opening 1c of the inverter housing 17 can be eliminated by the above-described configuration of the plurality of fixing portions 20a to 20e included in the capacitor 16. Furthermore, the strength equivalent to the strength of the bottom surface can be secured by fixing the inverter housing 17 to the motor housing 2. As a result, strength and sealing performance can also be secured.

[0035] Furthermore, in a conceivable case where the inverter 1 is mounted too tightly, due to the configuration of the present invention, the inverter case 17 is elastically deformed even if vibration or shock is directly transmitted to the mounting portions. Therefore, a shock-absorbing effect can be expected.

[0036] According to the above-described embodiment of the present invention, the following operational effects are produced.

[0037] (1) The power conversion device, which is fixedly connected to the motor housing 2 that houses the motor, includes the casing 17 having the plurality of side walls and having the opening on the motor side, the cover 11 covering the upper surface of the casing 17, and the plurality of internal components housed in the casing 17. The plurality of internal components include the capacitor 16, and the casing 17 includes the connecting portion 3 connected to the motor housing 2 and the plurality of fixing portions 17b that fix the capacitor 16 to the inside of the casing 17.In the housing 17, the first space 1a is provided between the capacitor 16 and the cover 11, the second space 1b is provided between the capacitor 16 and the motor, and the plurality of internal components are arranged to connect the pair of opposing side walls among the plurality of side walls. Such a configuration makes it possible to reduce the number of reinforcement members such as a bottom plate, cushion the impact on the mounting portions 20a to 20e and the capacitor 16, improve the routing property of the wiring, and reduce costs due to the loosening of tolerance.

[0038] (2) In the inverter case 17, the side walls have a rigidity lower than the rigidity of the mounting portions 20a to 20e. Such a configuration makes it possible to reduce the weight of the inverter case 17 and increase the rigidity of the mounting portions 20a to 20e.

[0039] (3) The capacitor 16 is arranged to connect the pair of opposite side walls among the plurality of side walls. With this configuration, the strength of the inverter case 17 can be ensured.

[0040] (4) The plurality of fixing portions 20a to 20e include a pair of fixing portions that form a truss shape with the corner portion of the capacitor 16 when viewed from the cover 11 side. Thus, the strength of the elements in the capacitor 16 can be secured, and the range of influence of the support can be expanded.

[0041] (5) The plurality of fixing portions 20a to 20e include a combination of fixing portions arranged at different positions in a thickness direction of the capacitor 16. In this way, the strength of the elements in the capacitor 16 can be secured and the range of influence of the support can be expanded.

[0042] (6) The plurality of fixing portions 20a to 20e include a combination of fixing portions arranged at an identical position in a thickness direction of the capacitor 16. In this way, the strength of the elements in the capacitor 16 can be secured, the range of influence of the support can be expanded, and manufacturability can be ensured.

[0043] Note that the present invention is not limited to the above embodiment, and various modifications and other configurations can be combined without departing from the gist of the present invention. Furthermore, the present invention is not limited to one that includes the entire configuration described in the above embodiment, and includes one from which part of the configuration is deleted. List of reference symbols 1 inverter 1a first room 1b second room 1c Opening 2 engine housings 3 Housing connection section 11 upper cover 12 LV connectors 13 Mass substrate 14 Power module 15 Busbar 16 Capacitor 16a to 16c corner section 17 Inverter housing 17a Housing mounting section 17b Capacitor mounting section 18 DC connectors 20 Fastening element 20a to 20e fastening section QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2013-115903 A

[0003]

Claims

[1] Power conversion device permanently connected to a motor housing that accommodates a motor, the power conversion device comprising: a housing with a multitude of side walls and with an opening on one side of the motor; a cover that covers an upper surface of the housing; and a large number of internal components that are housed within the casing, the multitude of internal components includes a capacitor, wherein the housing includes a connecting section that is connected to the motor housing and a plurality of mounting sections that attach the capacitor to an inside of the housing, wherein a first space is provided in the housing between the capacitor and the cover and a second space is provided between the capacitor and the motor, and wherein the multitude of internal components is arranged to connect a pair of opposing side walls beneath the multitude of side walls. [2] Power conversion device according to claim 1, wherein the plurality of side walls has a stiffness that is less than the stiffness of the plurality of fastening sections. [3] Power conversion device according to claim 1, wherein the capacitor is arranged to connect the pair of opposing side walls under the plurality of side walls. [4] Power conversion device according to claim 1, wherein the plurality of fastening sections includes a pair of fastening sections which, viewed from a cover side, forms a truss shape with respect to a corner section of the capacitor. [5] Power conversion device according to claim 1, wherein the plurality of fastening sections includes a combination of fastening sections arranged at different positions in a thickness direction of the capacitor. [6] Power conversion device according to claim 1, wherein the plurality of fastening sections includes a combination of the fastening sections which are arranged at an identical position in one thickness direction of the capacitor.

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