Housing and electronic device having the same

Abstract

The present invention provides a housing and an electronic device having the same, which can suppress vibration with a structure having a high degree of freedom in adjusting natural vibration and without excessively increasing the weight. The housing 3 includes a housing main body 10 having a storage space 10b capable of storing a circuit board 2 and opening on one side, and a lid 20 capable of being mounted on the housing main body 10 so as to close the opening of the housing main body 10. The lid 20 includes an annular first region portion 21 in contact with the housing main body 10, a second region portion 22 located on the inner peripheral side compared with the first region portion 21, a third region portion 23 located between the first region portion 21 and the second region portion 22 and connected to the first region portion 21 and the second region portion 22, and a ridge 25 extending to the third region portion 23 and connected to the second region portion 22. The mass per unit area of the second region portion 22 is greater than that of the third region portion 23 when observed from the mounting direction D of the lid 20 with respect to the housing main body 10. The ridge 25 is provided with a notch 26 at a position other than the front end portion in its extending direction.

Description

Technical Field

[0001] The present invention relates to a housing for accommodating a circuit and the like, and an electronic device having the same. More specifically, the present invention relates to a housing mounted on a device serving as a vibration source and an electronic device having the same. Background Art

[0002] In order to protect the environment, the application of electric vehicles is progressing. For a drive unit for an electric vehicle, miniaturization and weight reduction are required from the viewpoints of mountability and efficiency. On the other hand, quietness is required from the viewpoint of comfort. When the drive unit is composed of, for example, an electric motor, a gear, and an inverter, vibrations caused by the electromagnetic exciting force of the electric motor and the meshing force of the gear are transmitted to the housing of the inverter, resulting in sound radiation. Therefore, it is necessary to suppress sound radiation from the housing of the inverter. However, as the drive unit is miniaturized and weight-reduced, the housing cover of the inverter also tends to become thinner, and there is a concern that the vibration increases due to the reduction in rigidity caused by the thinning.

[0003] As a method for suppressing sound radiation from the housing caused by vibration propagation, for example, the technique described in Patent Document 1 has been proposed. In the housing structure for accommodating an electronic component described in Patent Document 1, the housing for accommodating the electronic component is composed of a first component (upper housing) and a second component (lower housing), and the first component (upper housing) and the second component (lower housing) are fastened by a fastening member. The upper housing has a fastening portion fastened by the fastening member on its surface. The upper housing is a component formed as a cover for the lower housing, which is the main body portion for accommodating the electronic component, and has a structure that is less rigid and more likely to vibrate than the lower housing. Then, a rib is provided on the upper housing along a direction from a specified position on the surface of the upper housing toward the fastening portion.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2016 / 006361 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the housing structure described in Patent Document 1, by providing a rib from the central portion (the position of the antinode of vibration) of the upper housing to the relatively rigid fastening portion located on the outer peripheral portion, the rigidity of the upper housing is increased to reduce vibration.

[0009] However, in the case of suppressing the vibration of the upper housing by increasing the rigidity with ribs, the rigidity of the region other than the region where the ribs are provided is relatively low. Therefore, the position of the antinode of the vibration may move to the region with relatively low rigidity. When new ribs are added to increase the rigidity of the region where the antinode of the moved vibration is located, as a result, multiple ribs are provided, and the weight of the upper housing may become too large.

[0010] In addition, when the rigidity of the upper housing is increased with ribs, the frequency of the first-order vibration of the membrane surface of the upper housing (first-order natural vibration frequency) increases. At this time, the first-order natural vibration frequency may change to the range of 1 kHz to 5 kHz. In the range of frequencies from 1 kHz to 5 kHz, the sensitivity of human hearing is relatively high. On the other hand, when the frequency is less than 1 kHz, the lower the frequency, the lower the sensitivity of human hearing. Therefore, when increasing the rigidity of the upper housing, it is preferable to suppress the changed first-order natural vibration frequency to less than 1 kHz where the sensitivity of human hearing is low. In addition, the upper housing before the ribs are provided has lower rigidity than the lower housing, and there is no problem of resonance with the lower housing. However, there is a concern of resonance with the lower housing because the rigidity of the upper housing after the ribs are provided is increased. Thus, it is difficult to adjust the first-order natural vibration frequency of the upper housing to a frequency where the sensitivity of human hearing is low and a frequency where there is no resonance with other components, and at the same time reduce the vibration of the upper housing only by providing ribs on the upper housing.

[0011] The present invention is made to solve the above problems, and an object thereof is to provide a housing that can suppress vibration without excessively increasing the weight with a structure having a high degree of freedom in adjusting the natural vibration frequency of components, and an electronic device having the same.

[0012] Technical solutions for solving the problems

[0013] This application includes various technical solutions for solving the above problems. Taking one example, it is characterized in that: it includes a housing main body having a storage space capable of storing a circuit inside and opening on one side, and a lid capable of being mounted on the housing main body so as to close the opening of the housing main body. The lid includes: an annular first region portion in contact with the housing main body; a second region portion located on the inner peripheral side compared with the first region portion; a third region portion located between the first region portion and the second region portion and connected to the first region portion and the second region portion; and a reinforcing portion connected to the second region portion and extending onto the third region portion. The second region portion is configured such that the mass per unit area when viewed from the mounting direction of the lid with respect to the housing main body is greater than that of the third region portion. The reinforcing portion is formed with a notch at a position other than the front end portion in its extending direction.

[0014] Effects of the invention

[0015] According to the present invention, by providing a notch in the reinforcing portion connected to the second region portion, the rigidity at the position of the notch in the third region portion where the reinforcing portion is provided is relatively low. Therefore, the position of the second region portion with a relatively large weight becomes a portion that is relatively easy to vibrate, and vibration can be suppressed without excessively increasing the weight of the second region portion. Furthermore, by adjusting the combination of the position and the shape such as the length, width, and height of the reinforcing portion, and the position and the shape such as the length and depth of the notch, the natural frequency of the cover can be adjusted to a frequency with a relatively low sensitivity of human hearing and a frequency that does not resonate with other components. That is, it is possible to suppress vibration with a structure having a relatively high degree of freedom in adjusting the natural vibration frequency of the component and without excessively increasing the weight.

[0016] Problems, structures, and effects other than those described above will be described through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. is a schematic view showing a vehicle drive unit of an electronic device according to a first embodiment of the present invention in a state of a partial cross section.

[0018] Figure 2 FIG. is a plan view showing a flat plate-shaped cover of an existing housing.

[0019] Figure 3 FIG. is a sectional view of the existing flat plate-shaped cover viewed in the III-III direction, and is an explanatory view showing the first vibration mode of the cover. Figure 2 FIG. is a sectional view of the existing flat plate-shaped cover viewed in the III-III direction, and is an explanatory view showing the first vibration mode of the cover.

[0020] Figure 4 FIG. is a plan view showing a cover of a first comparative example of an existing structure in which a weight-increasing structural portion is added to an existing flat plate-shaped cover.

[0021] Figure 5 FIG. is a sectional view of the cover of the first comparative example viewed in the V-V direction. Figure 4 FIG. is a sectional view of the cover of the first comparative example viewed in the V-V direction.

[0022] Figure 6 FIG. is a plan view showing a cover of a second comparative example of an existing structure in which a ridge is added to an existing flat plate-shaped cover.

[0023] Figure 7 FIG. is a plan view showing a cover of a housing in an electronic device according to a first embodiment of the present invention. Figure 1 FIG. is a plan view showing a cover of a housing in an electronic device according to a first embodiment of the present invention.

[0024] Figure 8 FIG. is a sectional view of the cover of the housing according to the first embodiment of the present invention viewed in the VIII-VIII direction. Figure 7 FIG. is a sectional view of the cover of the housing according to the first embodiment of the present invention viewed in the VIII-VIII direction.

[0025] Figure 9 FIG. is a plan view showing a cover of a housing according to a second embodiment of the present invention.

[0026] Figure 10 Viewed in the X-X direction Figure 9 Cross-sectional view of the cover of the housing of the second embodiment of the present invention shown in the figure. Detailed implementation mode

[0027] Hereinafter, embodiments of the housing of the present invention and an electronic device having the same will be described with reference to the accompanying drawings. In this embodiment, a case where the electronic device of the present invention is applied to an inverter for a rotating electric machine will be described as an example.

[0028] [First Embodiment]

[0029] First, the structure of an inverter as an electronic device and a vehicle drive unit having the same according to the first embodiment of the present invention will be described using Figure 1 for illustration. Figure 1 is a schematic diagram showing a vehicle drive unit having an electronic device according to the first embodiment of the present invention in a partial cross-sectional state.

[0030] Figure 1 In this, the drive unit 100 is used as a drive source for an electric vehicle such as an electric vehicle or a hybrid vehicle and is mounted on the vehicle. The drive unit 100 has, for example, a rotating electric machine 101, a transmission 102, and an inverter 1 as an electronic device. The rotating electric machine 101 and the transmission 102 are connected to each other, and a drive shaft (not shown) for driving a drive tire (not shown) is connected to the end portion 103 of the output shaft of the drive unit 100.

[0031] On the rotating electric machine 101, the inverter 1 is fixed via a mounting portion 101a. The rotating electric machine 101 functions as a motor, for example, and a rotor and a stator (both not shown) are housed in a housing 101b. The rotating electric machine 101 vibrates due to an electromagnetic excitation force generated in the gap between the rotor and the stator during driving, and thus becomes an excitation source for the inverter 1. The transmission 102 is a mechanism that transforms and transmits the rotational speed and torque of the driving force, and transforms and transmits the rotational speed and torque of the rotating electric machine 101 to the drive shaft. The inverter 1 converts DC power from a battery or the like (not shown) into AC power and supplies it to the rotating electric machine 101, and controls the power supply to the rotating electric machine 101. In the drive unit 100, a drive torque or a braking torque is generated according to an instruction from the inverter 1.

[0032] The inverter 1 has a circuit for controlling electric power, namely a circuit board 2, and a housing 3 that houses the circuit board 2. Various electronic components (not shown) are mounted on the circuit board 2 on a substrate. The housing 3 is constituted by, for example, a bottomed cylindrical housing body 10 having an opening 10a into which the circuit board 2 can be inserted and a housing space 10b inside that can house the circuit board 2, and a lid 20 that is detachably mounted on the housing body 10 so as to close the opening 10a of the housing body 10.

[0033] The housing body 10 has, for example, a bottom 11 mounted on a mounting portion 101a of a rotating electric machine 101, a cylindrical side wall portion 12 erected from the outer peripheral edge portion of the bottom 11, and an annular flange portion 13 protruding radially inward from the opening edge portion of the side wall portion 12. For example, the bottom 11 is a rectangular plate-like portion that is longer on one side, and the side wall portion 12 is a square cylindrical portion. The flange portion 13 is a portion that functions as a mounting portion for mounting the lid 20. The housing body 10 is fastened to the mounting portion 101a of the rotating electric machine 101 with bolts (not shown). Regarding the lid 20, for example, its outer peripheral portion is fastened to the flange portion 13 of the housing body 10 with bolts 30. The detailed structure of the lid 20 will be described later.

[0034] Vibrations during the driving of the drive unit 100 are transmitted to the housing 3. Specifically, vibrations generated in the rotating electric machine 101 and the speed changer 102 are first transmitted to the housing body 10 of the housing 3 via the mounting portion 101a, and then transmitted to the lid 20 via the contact portion between the housing body 10 and the lid 20.

[0035] Generally, the lid of an existing housing has a structure that is lower in rigidity and more prone to vibration compared to other components such as the housing body of the rotating electric machine 101 and the housing body of the existing housing. Therefore, the vibrations transmitted to the existing lid are amplified, and as a result, the sound radiation from the existing lid may increase.

[0036] Next, the structure of the existing lid and its vibrations will be described with reference to the drawings. First, the structure and vibrations of an existing flat lid will be described using Figure 2 and Figure 3 for illustration. Figure 2 is a plan view showing an existing flat lid of a housing. Figure 3 is a sectional view of the existing flat lid shown in Figure 2 as viewed in the III-III direction. Additionally, Figure 2 and Figure 3 in, the same reference numerals as those shown in Figure 1 denote the same parts, and the description thereof will be omitted.

[0037] Figure 2 and Figure 3In the figure, the existing flat cover 120 is a flat component installed on the housing body 10 (refer to Figure 1 ) having a rectangular opening 10a. The flat cover 120 is composed of an annular outer peripheral portion 121 in contact with the housing body 10 and a main body portion 122 surrounded by the outer peripheral portion 121. The outer peripheral portion 121 of the flat cover 120 is installed on the housing body 10, making it more rigid than the main body portion 122. The flat cover 120 is formed in a rectangular shape that is longer in one direction ( Figure 2 and Figure 3 the left-right direction in the figure).

[0038] Figure 3 The two-dot chain line in represents the first vibration mode of the flat cover 120. When the flat cover 120 is rectangular, the outer peripheral portion 121 of the flat cover 120 becomes a node 120a of the first vibration mode, and the central portion of the main body portion 122 becomes an antinode (the position with the largest amplitude) 120b of the first vibration mode.

[0039] The existing flat cover 120 has a structure that is less rigid and more prone to vibration compared to other components such as the housing 101b of the rotary electric machine 101 (refer to Figure 1 ). Therefore, the vibration of the driving portion of the drive unit 100 (refer to Figure 1 ) is transmitted to the flat cover 120 through the housing body 10 of the housing, causing the main body portion 122 of the flat cover 120 to vibrate and increasing the sound radiation. As an existing method for reducing the vibration of the existing flat cover 120, increasing the partial weight of the flat cover 120 and providing ribs, etc. can be cited.

[0040] Next, the lid of the first comparative example of the existing structure that can reduce the vibration of the existing flat cover will be described using Figure 4 and Figure 5 . Figure 4 is a plan view of the lid of the first comparative example showing a structural portion with an increased weight added to the existing flat cover. Figure 5 is a cross-sectional view of the lid of the first comparative example observed in the V-V direction looking at Figure 4 shown.

[0041] Figure 4 and Figure 5 In and , the existing lid 220 of the first comparative example increases the weight of the region with a larger amplitude in the existing flat cover 120 (refer to Figure 2 and Figure 3 ) compared to other regions. Specifically, the lid 220 of the first comparative example is composed of the housing body 10 (refer to Figure 1 ​)It is composed of an outer peripheral portion 221 in contact, a weight portion 222 located on the inner peripheral side compared to the outer peripheral portion 221, and a main body portion 223 located between the outer peripheral portion 221 and the weight portion 222 and connecting the outer peripheral portion 221 and the weight portion 222.

[0042] The outer peripheral portion 221 is mounted on the housing main body 10, thereby increasing rigidity. The main body portion 223 is an annular plate-like portion extending from the outer peripheral edge of the weight portion 222 to the inner peripheral edge of the outer peripheral portion 221, and is a portion with relatively lower rigidity than the outer peripheral portion 221 and the weight portion 222. The weight portion 222 is configured such that the mass (weight) per unit area is relatively larger than that of the main body portion 223, and is a portion thicker than the main body portion 223. The weight portion 222 is disposed at the central portion of the cover 220.

[0043] In the cover 220 of the first comparative example, by setting the configuration of the weight portion 222 such that the center of the weight portion 222 is located at the antinode position of the first-order vibration mode of the cover 220, the effect of suppressing vibration with the weight portion 222 of the cover 220 can be exerted. However, when the cover shape is other than a simple shape such as a rectangle or a circle, as a certain portion is thickened, the rigidity of the entire cover 220 changes, so the antinode position of the first-order vibration mode of the cover 220 may appear near the outer edge portion of the weight portion 222. In this case, compared with the case where the antinode position of the first-order vibration mode is near the central portion of the weight portion 222, the effect of suppressing vibration cannot be fully exerted, and there is a concern that vibration suppression cannot be achieved without significantly increasing the weight.

[0044] Next, the cover of the second comparative example of the existing structure for reducing the vibration of the existing flat cover is used Figure 6 for description. Figure 6 It is a plan view of the cover of the second comparative example of the existing structure in which ribs are added to the existing flat cover.

[0045] Figure 6 In [it], the existing cover 320 of the second comparative example adds reinforcing ribs 325 to the existing flat cover 120 (reference Figure 2 and Figure 3 ). Specifically, the cover 320 of the second comparative example is composed of an annular outer peripheral portion 321 in contact with the housing main body 10 (reference Figure 1 ), a main body portion 322 surrounded by the outer peripheral portion 321, and ribs 325 provided on the main body portion 322.

[0046] The outer peripheral portion 321 is attached to the housing main body 10, thereby increasing rigidity. The ribs 325 enhance the rigidity of the main body portion 322, and a plurality of ribs 325 are provided on the main body portion 322. The ribs 325 extend from the vicinity of the outer peripheral portion 321 with relatively high rigidity to the central portion of the main body portion 322 (the position of the antinode of the first-order vibration mode). By increasing the rigidity of the central portion of the main body portion 322 (the position of the antinode of the first-order vibration mode) with a plurality of ribs 325, the vibration of the lid 320 of the second comparative example is reduced.

[0047] However, when suppressing the vibration of the lid 320 by providing the ribs 325, the rigidity of the region in the main body portion 322 different from the rib-providing region is relatively low, so the antinode of the first-order vibration mode may move to this low-rigidity region. At this time, new ribs need to be added to the main body portion 322, so there is a concern that the weight of the lid may become too large as a result of providing a plurality of ribs.

[0048] In addition, when suppressing the vibration of the lid 320 of the second comparative example by increasing the rigidity with the ribs 325, the first natural vibration frequency of the lid 320 increases compared to before the ribs 325 are provided. At this time, this natural vibration frequency may change within the range of 1 kHz to 5 kHz. In the frequency range of 1 kHz to 5 kHz, the sensitivity of human hearing is relatively high. On the other hand, when the frequency is less than 1 kHz, the lower the frequency, the lower the sensitivity of human hearing. Therefore, it is preferable that the first natural vibration frequency of the lid 320 does not change within the range of 1 kHz to 5 kHz, but is less than 1 kHz. In addition, the lid before the ribs 325 are provided has lower rigidity compared to the housing 101b of the rotating electric machine 101 (refer to Figure 1 ) and the housing main body 10, and there is no problem of resonance with other components such as the housing main body 10. However, for the lid 320 of the second comparative example after the ribs 325 are provided, since the first natural vibration frequency increases due to the increased rigidity, there is a concern about resonance with other components. Based on the above, it is difficult to adjust the first natural vibration frequency of the lid 320 of the second comparative example to a frequency with low sensitivity of human hearing and a frequency that does not cause resonance with other components, and at the same time reduce the vibration of the lid 320 only by providing the ribs 325.

[0049] Therefore, the lid 20 of the present embodiment suppresses vibration by having the following structure. Next, the structure of the lid of the housing constituting the first embodiment of the present invention will be described using Figure 7 and Figure 8 for explanation. Figure 7 is a plan view showing the lid of the housing in the electronic device of the first embodiment of the present invention shown in Figure 1 . Figure 8 is a cross-sectional view of the lid of the housing of the first embodiment of the present invention as viewed in the VIII-VIII direction of Figure 7 .

[0050] Figure 7 and Figure 8 In the [description], the cover 20 has a plate-like portion that closes the opening 10a of the housing main body 10 as a basic structure, and further has a structural portion that increases the weight of only a certain area of the plate-like portion and a structural portion that improves the rigidity of the plate-like portion. Specifically, the cover 20 has an annular first region portion 21 that contacts the flange portion 13 of the housing main body 10, a second region portion 22 as a weight portion located on the inner peripheral side compared to the first region portion 21, and a third region portion 23 located between the first region portion 21 and the second region portion 22 and connecting the first region portion 21 and the second region portion 22. The cover 20 is, for example, a rectangular member having a length direction L that is longer in one direction (the left-right direction in [reference Figure 8 ) when viewed from the mounting direction D of the housing main body 10 (reference Figure 7 ) corresponding to the shape of the opening 10a of the housing main body 10 (reference Figure 7 ). In the cover 20, for example, the first region portion 21, the second region portion 22, and the third region portion 23 are formed integrally.

[0051] The first region portion 21 is, for example, a plate-like portion integral with the third region portion 23 and constitutes the outer peripheral portion of the cover 20. In the first region portion 21, one surface (the lower surface in [reference Figure 8 ) becomes the contact surface with the flange portion 13. The first region portion 21 is fastened to the flange portion 13 by bolts 30, thereby increasing its rigidity.

[0052] The third region portion 23 is a portion that surrounds the second region portion 22 and is surrounded by the first region portion 21. The third region portion 23 is, for example, an annular plate-like portion extending from the outer peripheral edge of the second region portion 22 to the inner peripheral edge of the first region portion 21 and is a portion with relatively lower rigidity than the first region portion 21 and the second region portion 22.

[0053] The second region portion 22 is configured such that the mass (weight) per unit area when viewed from the mounting direction D of the cover 20 with respect to the housing main body 10 (the thickness direction of the third region portion 23 of the cover 20 or the direction orthogonal to the contact surface with the first region portion 21) is relatively larger than that of the third region portion 23. The second region portion 22 is, for example, a thicker portion than the third region portion 23 and bulges toward the outside of the housing 3 (reference Figure 1 ) compared to the third region portion 23. The raised portion 22a of the second region portion 22 is formed, for example, corresponding to the shape of the cover 20 in one direction ( Figure 7 and Figure 8In the left - right direction (in the figure), it is in the shape of a relatively long cuboid. The position of the second region portion 22 is set such that the position of the antinode (the position with the maximum amplitude) of the first - order vibration mode of the lid 20 is included within the range of the second region portion 22. The position of the second region portion 22 is preferably set such that the center of the second region portion 22 becomes the position of the antinode of the first - order vibration mode of the lid 20. The second region portion 22 is, for example, located at the approximate center of the lid 20 when viewed in the mounting direction D of the lid 20 with respect to the housing main body 10. The second region portion 22 is, for example, formed integrally with the third region portion 23.

[0054] On the third region portion 23, a reinforcing portion 25 for increasing the rigidity of the third region portion 23 extends in a manner connected to the second region portion 22. Specifically, the reinforcing portion 25 is, for example, composed of four ridges provided on the outer - surface side (the surface on the outer - world side of the outer shell 3) of the third region portion 23. The four ridges 25 are, for example, respectively connected to the four corner portions that protrude in the protruding direction (in the up - down direction in the figure) of the cuboid - shaped raised portion 22a of the second region portion 22, and extend along the length direction L of the lid 20 to approximately the middle point of the third region portion 23. That is, each ridge 25 is connected to the second region portion 22 but does not reach the first region portion 21. Two adjacent ridges 25 among the four ridges 25 in the shorter direction of the lid 20 are arranged opposite to each other. The ridge 25 is, for example, formed integrally with the second region portion 22 and the third region portion 23. Figure 8 Among the ridges 25 as the reinforcing portion, notches 26 are provided at positions other than the front - end portion in the extending direction. The notch 26 is, for example, formed from the central portion in the extending direction of the ridge 25 to reach the position of the second region portion 22. The depth of the notch 26 is, for example,

[0055] as shown, set to about 1 / 3 of the height of the ridge 25. Figure 8

[0056] The shape of the ridge 25 such as the length, width (thickness), and height of the ridge 25, and the shape of the notch 26 such as the position, length, and depth of the notch 26 are set such that the position of the antinode of the first - order vibration mode of the lid 20 is within the range of the second region portion 22. Further, the shapes of the ridge 25 and the notch 26 are set to avoid the first - order natural vibration frequency of the lid 20 from falling within the range of the natural vibration frequencies of other components such as the housing main body 10 or the frequency range where the sensitivity of human hearing is relatively high (for example, the range from 1 kHz to 5 kHz). In other words, by adjusting various parameters of the ridge 25 and the notch 26, the position of the antinode of the first - order vibration mode of the lid 20 can be changed. In addition, by adjusting various parameters of the ridge 25 and the notch 26, the first - order natural vibration frequency of the lid 20 can be set within a specified frequency range.

[0057] Next, regarding the functions and effects of the lid, which is a part of the outer shell constituting the first embodiment of the present invention, use Figure 7 and​Figure 8 will be described.

[0058] In the present embodiment, as Figure 7 and Figure 8 shown, for the ridge 25 provided in the third region portion 23, a notch 26 is provided at a position other than its front end portion. Thus, the rigidity of the vicinity of the second region portion 22 (weight portion) in the third region portion 23 where the rigidity is increased by the ridge 25 can be intentionally reduced by the notch 26. As a result, a region with a relatively large amplitude is generated in the second region portion 22 (weight portion) and its periphery. Therefore, compared with the case where the notch 26 is not provided on the ridge 25, vibrations with a relatively large amplitude can be further suppressed by the second region portion 22 with a relatively high weight. Thereby, the sound radiation from the cover 20 is reduced. In addition, in order to concentrate the region with a relatively large amplitude in the second region portion 22 (weight portion), it is preferable that, as Figure 7 and Figure 8 shown, the notch 26 is provided up to the position reaching the second region portion 22.

[0059] In addition, in the cover 20 of the present embodiment, in addition to adjusting the setting position, length, height, width (thickness), etc. of the ridge 25, and the number of ridges 25, by adjusting the position, length, and height of the notch 26, etc., the position of the antinode of the first-order vibration mode of the cover 20 can be moved. Thus, compared with the cover 220 of the existing first comparative example having the weight portion 222 but no ridge (refer to Figure 4 and Figure 5 ), it is easy to adjust the position of the antinode of the first-order vibration mode of the cover 20 to the central portion of the second region portion 22 (weight portion) by the ridge 25 and the notch 26. That is, compared with the cover 220 of the existing first comparative example, the effect of suppressing vibration by the second region portion 22 as a weight portion can be more effectively exerted. Thus, the vibration of the cover 20 can be suppressed without a significant increase in weight.

[0060] In addition, in the cover 20 of the present embodiment, in addition to adjusting the setting position, shape, and number of ridges 25, by adjusting the position and shape of the notch 26, the first-order natural vibration frequency of the cover 20 can be changed. That is, there are a plurality of design parameters for setting the first-order natural vibration frequency of the cover 20 with respect to the ridge 25 and the notch 26. Thus, by adjusting the ridge 25 and the notch 26, the first-order natural vibration frequency of the cover 20 can be adjusted to a frequency range with low sensitivity of human hearing and a frequency range that does not resonate with other components. In addition, when the frequency at which the exciting force of the cover 20 is amplified is known, it is easy to avoid this frequency range by adjusting the ridge 25 and the notch 26.

[0061] In addition, since the human auditory sensitivity decreases as the frequency decreases below 1 kHz, it is considered to adjust the first-order natural vibration frequency of the cover 20 to a low frequency by adjusting the ridges 25 and the notches 26. However, in the drive unit 100 for an electric vehicle (refer to Figure 1 ), when the first-order natural vibration frequency of the cover 20 is excessively set to the low-frequency side, during acceleration in the low-speed range of the drive unit 100, the vibration of the drive unit 100 will inevitably pass through the first-order natural vibration frequency (resonance point) of the cover 20. Therefore, it is preferable to have a structure of the cover that can easily adjust the frequency of the first vibration mode while maintaining the balance between the frequency for the human auditory sensitivity and the vibration frequency during vehicle acceleration.

[0062] In the cover 20 of the present embodiment, the setting position, shape, number of the ridges 25 on the third region portion 23, the position and shape of the notches 26, and the weight and thickness of the second region portion 22 can be used as adjustment amounts for the natural vibration frequency of the cover 20. Therefore, compared with the covers 220 and 320 of the first comparative example and the second comparative example (refer to Figures 4 - 6 ), the adjustment amount of the natural vibration frequency of the cover 20 is larger, and it is easier to take into account reducing the vibration of the cover 20 and designing the natural vibration frequency of the cover 20.

[0063] Furthermore, in the cover 20 of the present embodiment, in addition to adjusting the setting position, shape, and number of the ridges 25, by adjusting the position and shape of the notches 26, compared with the existing covers 220 and 320 of the first comparative example and the second comparative example, the region with a relatively large amplitude in the third region portion 23 can be reduced.

[0064] In addition, in the present embodiment, mainly focusing on suppressing the vibration at the frequency of the first vibration mode of the cover 20, as shown in Figure 7 and Figure 8 , a plurality of ( Figure 7 shows 4) ridges 25 are provided along the length direction L of the cover 20 on the third region portion 23. However, in the drive unit 100, low-frequency vibrations mainly occur due to the meshing force of the gears of the transmission 102, and on the other hand, vibrations in the range from low frequency to high frequency occur due to the electromagnetic excitation force of the rotating electric machine 101. Thus, by adjusting the setting position of the ridges 25 to be at the position of the antinode of the higher-order (higher frequency) vibration mode or adjusting the number of the ridges 25, it is possible to suppress not only low-frequency vibrations but also high-frequency vibrations simultaneously.

[0065] The housing 3 of the first embodiment of the present invention and the inverter 1 (electronic device) having the same include a housing main body 10 having a storage space 10b capable of storing a circuit board 2 (circuit) therein and opening on one side, and a lid 20 mounted on the housing main body 10 so as to close the opening of the housing main body 10. The lid 20 has an annular first region portion 21 in contact with the housing main body 10, a second region portion 22 located on the inner peripheral side compared with the first region portion 21, a third region portion 23 located between the first region portion 21 and the second region portion 22 and connected to the first region portion 21 and the second region portion 22, and a ridge 25 (reinforcing portion) extending on the third region portion 23 and connected to the second region portion 22. The second region portion 22 is configured such that the mass per unit area is larger than that of the third region portion 23 when viewed from the mounting direction D of the lid 20 with respect to the housing main body 10. In the ridge 25 (reinforcing portion), notches 26 are provided at positions other than the front end portion in its extending direction.

[0066] According to this structure, by providing the notches 26 in the ridge 25 (reinforcing portion) connected to the second region portion 22, the rigidity at the position of the notch 26 in the third region portion 23 where the ridge 25 (reinforcing portion) is provided is relatively low, so the position of the relatively heavier second region portion 22 becomes a portion that is relatively easy to vibrate, and vibration can be suppressed without excessively increasing the weight of the second region portion 22. Furthermore, by adjusting the combination of the position and shape such as the length, width, and height of the ridge 25 (reinforcing portion), and the position and shape such as the length, depth, etc. of the notch 26, the natural frequency of the lid 20 can be adjusted to a frequency with a lower sensitivity of human hearing and a frequency that does not resonate with other components. That is, it is possible to suppress vibration with a structure having a high degree of freedom in adjusting the natural vibration frequency of the component and without excessively increasing the weight of the lid 20.

[0067] In addition, in the housing 3 of the present embodiment, the position of the second region portion 22 of the lid 20 is set such that the position of the antinode of the first-order vibration mode of the lid 20 is within the range of the second region portion 22.

[0068] According to this structure, since the vibration at the position of the antinode of the first-order vibration mode of the lid 20 is suppressed by the relatively heavier second region portion 22, the amplitude of this antinode can be reduced.

[0069] In addition, in the lid 20 of the housing 3 of the present embodiment, the notch 26 is formed from a certain position in the ridge 25 (reinforcing portion) to reach the position of the second region portion 22.

[0070] According to this structure, it is possible to concentrate the region with a relatively large amplitude in the second region portion 22. In this case, the relatively large weight of the second region portion 22 can be used to further reduce the region with a relatively large amplitude.

[0071] In addition, in the housing 3 of the present embodiment, the cover 20 is a member having a longitudinal direction L, and the ridge 25 (reinforcing portion) extends in the direction along the longitudinal direction L of the cover 20.

[0072] According to this structure, the ridge 25 can increase the rigidity of the low-rigidity portion in the longitudinal direction of the cover 20, that is, the longitudinal portion.

[0073] In addition, in the cover 20 of the housing 3 of the present embodiment, the second region portion 22 has a raised rectangular parallelepiped-shaped raised portion compared with the third region portion 23.

[0074] According to this structure, since the raised portion 22a of the second region portion 22 has a simple shape, the manufacture of the cover 20 is easy.

[0075] In addition, in the cover 20 of the housing 3 of the present embodiment, the reinforcing portion for increasing the rigidity of the third region portion 23 is constituted by ridges 25 respectively connected to four corner portions protruding in the raising direction (the outside of the housing 3) of the rectangular parallelepiped-shaped raised portion 22a of the second region portion 22.

[0076] According to this structure, it is possible to improve the rigidity of the cover 20 and reduce vibration with a weight portion and a reinforcing portion having a simple structure.

[0077] [Second Embodiment]

[0078] Next, the housing of the second embodiment of the present invention is used Figure 9 and Figure 10 for description. Figure 9 is a plan view showing the cover of the housing of the second embodiment of the present invention. Figure 10 is a sectional view of the cover of the housing of the second embodiment of the present invention as viewed in the X-X direction. In addition, Figure 9 In Figure 9 and Figure 10 , the parts indicated by the same reference numerals as those in Figure 1 , Figure 7 , Figure 8 shown in the drawings are the same parts, and their detailed descriptions are omitted.

[0079] Figure 9 and Figure 10 shown in the cover 20A of the housing of the second embodiment of the present invention and the cover 20 of the housing of the first embodiment (refer to Figure 7 and Figure 8 ) The main differences are that the arrangement and number of the ridges 25A as the reinforcing portion of the third region portion 23 are different and the position of the second region portion 22A in the cover 20A is different.

[0080] Specifically, the second region portion 22A of the cover 20A is located on one side in the longitudinal direction L compared with the position of the central portion in the cover 20A (Figure 9 and Figure 10 The position of the right (offset) side in. The reinforcing part of the third region part 23 is composed of two ridges 25A provided on the outer surface of the third region part 23 (the surface on the outer side of the outer shell 3 (refer to Figure 1 ). The two ridges 25A are connected corresponding to two of the four corner parts protruding in the protruding direction ( Figure 10 the up-and-down direction in) of the rectangular parallelepiped-shaped protruding part 22a of the second region part 22A, and extend along the length direction L of the lid 20A to a position that does not reach the first region part 21. That is, the two ridges 25A are not arranged on both sides ( Figure 9 the left and right sides in) of the length direction L of the second region part 22A, but are arranged to be biased to one side ( Figure 9 and Figure 10 the left side in) of the length direction L of the second region part 22A. Figure 9 and Figure 10 in).

[0081] In each of the ridges 25A, similarly to the first embodiment, a notch 26 is provided at a position other than the front end portion in its extending direction. The shape of each of the ridges 25A such as the length, width (thickness), and height, and the position of the notch 26, the shape of the length and depth of the notch 26, are set to prevent the first-order natural vibration frequency of the lid 20A from falling within the range of the natural vibration frequency of other components such as the housing main body 10 or the frequency range with high sensitivity of human hearing (for example, the range of 1 kHz to 5 kHz). Further, the shape of the ridge 25A and the notch 26 is set so that the position of the antinode of the first-order vibration mode of the lid 20A is within the range of the second region part 22A (a position offset to one side in the length direction L compared to the central portion of the lid 20A).

[0082] In this embodiment, similarly to the first embodiment, for the ridge 25A provided in the third region part 23, a notch 26 is provided at a position other than its front end portion. Thereby, the rigidity of the vicinity of the second region part 22A (weight part) in the third region part 23 whose rigidity is increased by the ridge 25A can be intentionally reduced by this notch 26. As a result, a region with a relatively large amplitude is generated in the second region part 22A (weight part) and its periphery. Therefore, compared with the case where no notch 26 is provided on the ridge 25A, the vibration with a relatively large amplitude can be further suppressed by the second region part 22 with a relatively high weight. Thus, the sound radiation from the lid 20A is reduced. In addition, in order to concentrate the region with a relatively large amplitude in the second region part 22A (weight part), it is preferable that, as shown in Figure 9 and Figure 10 , the notch 26 is provided to reach the position of the second region part 22A.

[0083] In addition, in the present embodiment, similar to the first embodiment, in addition to adjusting the position and shape (length, width, height) of the ridge 25A, by adjusting the position and shape (length, depth) of the notch 26, it is possible to move the position of the antinode of the first-order vibration mode of the lid 20A.

[0084] Accordingly, it is easy to adjust the position of the antinode of the first-order vibration mode of the lid 20A to the central portion of the second region portion 22A (weight portion).

[0085] In addition, in the present embodiment, similar to the first embodiment, in addition to adjusting the position and shape (length, width, height) of the ridge 25A, by adjusting the position and shape (length, depth) of the notch 26, it is possible to change the first-order natural vibration frequency of the lid 20A. That is, there are a plurality of design parameters for setting the frequency of the first-order vibration mode of the lid 20A with respect to the ridge 25A and the notch 26. Accordingly, by adjusting the ridge 25A and the notch 26, it is possible to adjust the first-order natural vibration frequency of the lid 20A to a frequency range where the sensitivity of human hearing is low and no resonance occurs with other components.

[0086] As described above, in the second embodiment of the present invention, similar to the first embodiment, it is possible to suppress vibration with a structure having a high degree of freedom in adjusting the natural vibration frequency of the component and without excessively increasing the weight of the lid 20A.

[0087] In addition, in the lid 20A of the housing of the present embodiment, the reinforcing portion that increases the rigidity of the third region portion 23 is constituted by the ridge 25A that is respectively connected to two adjacent corner portions among the four corner portions that protrude in the protruding direction (the outside of the housing 3) in the rectangular parallelepiped-shaped protruding portion 22a of the second region portion 22A.

[0088] According to this structure, it is possible to increase the rigidity of the lid 20A and reduce vibration with a reinforcing portion having a simpler structure than the lid 20 of the first embodiment.

[0089] [Other Embodiments]

[0090] In addition, in the above-described first and second embodiments, an example in which the electronic device of the present invention is applied to the inverter 1 for a motor has been described, but it can also be applied to the inverter 1 for a motor generator. In addition, an example in which the present invention is applied to the inverter 1 used in the rotating electric machine 101 has been shown, but the present invention can be applied to various electronic devices that house a circuit in a housing.

[0091] In addition, the present invention is not limited to the above-described embodiments and includes various modifications. The above-described embodiments have been described in detail for easy understanding of the present invention and are not limited to having all the structures described. A part of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can also be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0092] For example, in the above-described embodiments, an example is shown in which a plurality of ridges 25, 25A are provided along the length direction L of the covers 20, 20A. However, as long as the ridges 25, 25A are structures connected to the second region portions 22, 22A, the installation position, the extending direction, etc. can be arbitrarily adjusted.

[0093] In addition, in the above-described embodiments, an example is shown in which the ridges 25, 25A are provided on the outer surface side (the outside of the outer shell 3) of the third region portion 23 of the covers 20, 20A. However, a structure in which the ridges 25, 25A are provided on the inner surface side (the side of the accommodation space 10b of the housing main body 10) of the third region portion 23 is also possible.

[0094] In addition, in the above-described embodiments, an example is shown in which the raised portions 22a of the second region portions 22, 22A bulge toward the outside of the outer shell 3. However, a structure in which the raised portions bulge toward the accommodation space 10b of the housing main body 10 is also possible.

[0095] In addition, in the above-described embodiments, an example is shown in which the raised portions 22a of the second region portions 22, 22A are formed in a rectangular parallelepiped shape. However, as long as the weight of the second region portions 22, 22A is relatively greater than that of the third region portion 23, the shape of the raised portions can be arbitrary.

[0096] In addition, in the above-described embodiments, an example is shown in which the covers 20, 20A in which the weight portions, i.e., the second region portions 22, 22A, and the reinforcing portions, i.e., the ridges 25, 25A, are integrally formed with the third region portion 23. However, the cover can also be manufactured by attaching the raised portions 22a of the second region portions 22, 22A formed separately and the ridges 25, 25A formed separately to a plate-like member including the first region portion 21 and the third region portion 23.

[0097] In addition, in the above-described embodiments, an example is shown in which the first region portion 21 of the covers 20, 20A is a flat outer peripheral portion continuous with the outer peripheral edge portion of the plate-like third region portion 23. However, the first region portion of the cover can also be configured as an annular protruding strip portion protruding toward the housing main body 10 side from the outer peripheral edge portion of the flat plate-like third region portion 23. In this case, in the annular protruding strip portion as the first region portion, the front end surface is the contact portion with the housing main body 10.

[0098] In addition, in the above-described embodiments, an example is shown in which the shapes of the covers 20 and 20A, when viewed from the mounting direction D of the covers 20 and 20A with respect to the housing main body 10, are rectangles having a longitudinal direction L. However, the shapes of the covers 20 and 20A are arbitrary corresponding to the shape of the housing main body of the outer shell.

[0099] Description of Reference Numerals

[0100] 1... Inverter (electronic device), 2... Circuit board (circuit), 3... Outer shell, 10... Housing main body, 10a... Opening, 10b... Storage space, 20, 20A... Covers, 21... First region portion, 22, 22A... Second region portions, 22a... Protrusion, 23... Third region portion, 25, 25A... Edges (reinforcing portions), 26... Notch.

Claims

1. A housing, characterized in that: it includes a housing main body having a receiving space capable of receiving a circuit therein and opening on one side, and a cover capable of being mounted on the housing main body in a manner of closing the opening of the housing main body, the cover includes: an annular first region portion in contact with the housing main body; a second region portion located on the inner circumferential side compared with the first region portion; a third region portion located between the first region portion and the second region portion and connecting the first region portion and the second region portion; and a reinforcing portion connected to the second region portion and extending onto the third region portion, the second region portion is configured such that the mass per unit area is greater than that of the third region portion when observed from the mounting direction of the cover with respect to the housing main body, in the reinforcing portion, a notch for reducing the rigidity of the reinforcing portion is formed from a position other than the front end portion in the extending direction of the reinforcing portion to a position reaching the second region portion, so that the position of the antinode of the first-order vibration mode of the cover is within the range of the second region portion.

2. The housing according to claim 1, characterized in that: the cover is a member having a length direction, and the reinforcing portion extends in a direction along the length direction of the cover.

3. The housing according to claim 1, characterized in that: the second region portion has a rectangular parallelepiped-shaped raised portion that is raised compared with the third region portion.

4. The housing according to claim 3, characterized in that: the reinforcing portion is composed of ridges respectively connected to four corner portions protruding in the raising direction of the raised portion.

5. The housing according to claim 3, characterized in that: the reinforcing portion is composed of ridges respectively connected to two adjacent corner portions among the four corner portions protruding in the raising direction of the raised portion.

6. An electronic device including a circuit and a housing for receiving the circuit, characterized in that: the housing is the housing according to claim 1.

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