JP7655669B2 - Equipment Unit - Google Patents

Description

This disclosure relates to an equipment unit.

Various efforts have been made to reduce noise in vehicle-mounted equipment. For example, the intake manifold described in JP 2015-197080 A includes a surge tank, a branch pipe, and two partition walls.

The two partition walls are formed to connect the outer wall of the surge tank and the outer wall of the branch pipe, and are formed to separate the gap surrounded by the engine, the surge tank, and the branch pipe when the intake manifold is installed on the engine. One of the partition walls has multiple through holes, while the other partition wall has no through holes.

By forming two partition walls as described above, noise generated in the intake manifold is reduced.

JP 2015-197080 A

The electric vehicle includes a transaxle, a power control unit (PCU), and a boost converter. The transaxle includes a housing case and a rotating electric machine and a transmission housed within the housing case.

The PCU is fixed, for example, to the top surface of the transaxle case. The boost converter is placed at a distance above the PCU. This leaves a gap between the PCU and the boost converter.

The transaxle includes a housing case and a rotating electric machine and a transmission housed within the housing case. When the rotating electric machine and the transmission are driven, they vibrate. When the vibrations are transmitted to the housing case, the PCU vibrates.

When the PCU vibrates, air column resonance can occur in the gap between the PCU and the boost converter, causing noise to be radiated into the surrounding area.

In this way, when two devices are placed with a gap between them, air column resonance may occur in the gap, causing sound to be radiated into the surrounding area.

The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide an equipment unit that can suppress the radiation of noise caused by air column resonance to the surroundings when two pieces of equipment are placed with a gap between them.

The equipment unit according to the present disclosure is an equipment unit including a vibrating first device, a second device disposed with a gap from the first device, and a protrusion disposed on the outer periphery of the gap and formed to narrow the gap, in which, when the protrusion is not provided, the direction in which the traveling sound wave of the air column resonance generated in the gap propagates is defined as the propagation direction, and when the protrusion is not provided, the area of the gap projected in the propagation direction is defined as the opening area, and the area of the protrusion projected in the propagation direction is defined as the protruding area, and the protruding area is 15% or more of the opening area.

The above equipment unit can prevent noise caused by air column resonance from being emitted to the surroundings when two pieces of equipment are placed with a gap between them.

The protrusion is formed to protrude from the first device toward the second device, and the gap between the protrusion and the second device is 1.5 mm or less.

The equipment unit according to the present disclosure is an equipment unit including a first vibrating device and a second device arranged with a gap between the first device and the second device, and the distance between the first device and the second device is 0.6 mm or more and 1.5 mm or less.

The equipment unit disclosed herein can prevent noise caused by air column resonance from being emitted to the surroundings when two pieces of equipment are placed with a gap between them.

FIG. 1 is a front view that shows a schematic diagram of an equipment unit 1 and a transaxle 2 according to a first embodiment of the present invention. FIG. A plan view showing the upper surface 23 of the PCU 3. 2 is a perspective view showing a configuration of a protrusion 25 and the periphery of the protrusion 25. FIG. 2 is a plan view of the boost converter 4 and the PCU 3 as viewed from above the boost converter 4. FIG. 2 is a perspective view showing the PCU 3 and the boost converter 4, and is a perspective view showing the protrusion 25 and the surrounding configuration. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5. FIG. 2 is a perspective view showing an equipment unit 1A according to a comparative example. FIG. 11 is a perspective view showing a part of an equipment unit 1B according to a second embodiment. FIG. 2 is a plan view showing the equipment unit 1B. 12 is a cross-sectional view taken along line XII-XII in FIG. 11. 11 is a cross-sectional view taken along line XIII-XIII in FIG. 10. The figure shows the increase in sound volume when air column resonance occurs in equipment units having variously modified shapes of the protrusions 25B. 1 is a graph showing the peak increase in volume (dB) at the air column resonance frequency P1. FIG. 11 is a perspective view showing a part of an equipment unit 1C according to a third embodiment. FIG. 1 is a plan view showing an equipment unit 1C. This is a cross-sectional view taken along line XVIII-XVIII in Figure 17. This is a cross-sectional view taken along line XIX-XIX in Figure 17. 13 is a graph showing the increase in sound volume when air column resonance occurs in each equipment unit in which the shape of the protrusion 25C is changed in various ways. FIG. 2 is a perspective view showing a part of the equipment unit 1D. 13 is a graph showing an increase in sound volume when air column resonance occurs when the distance GP1D between the housing case 20D and the housing case 15D is changed in various ways. 13 is a graph showing the peak increase in volume (dB) at the air column resonance frequency P2. FIG. 13 is a perspective view showing an equipment unit 1E according to embodiment 5. FIG. 11 is a cross-sectional view showing an equipment unit 1E.

The equipment unit according to the present embodiment will be described with reference to Figures 1 to 25. Among the components shown in Figures 1 to 25, the same or substantially the same components are denoted by the same reference numerals and duplicated descriptions will be omitted.
(Embodiment 1)
FIG. 1 is a front view that shows a schematic diagram of an equipment unit 1 and a transaxle 2 according to the first embodiment.

The equipment unit 1 includes a PCU (power control unit) (first equipment) 3 and a boost converter (second equipment) 4. The PCU 3 is fixed to the upper surface of the transaxle (fixed member) 2. The boost converter 4 is disposed above the PCU 3 with a gap therebetween. A gap 5 is formed between the boost converter 4 and the PCU 3.

The transaxle 2 includes a housing case 10, rotating electric machines 11 and 12, and a transmission 13. The housing case 10 is made of metal. The rotating electric machines 11 and 12 and the transmission 13 are housed within the housing case 10.

The PCU 3 includes a housing case 15 and an inverter 16 housed in the housing case 15. The inverter 16 includes multiple switching elements such as IGBTs (Insulated Gate Bipolar Transistors). The housing case 15 is made of metal.

The boost converter 4 includes a housing case 20 and a boost circuit 21 housed in the housing case 20. The boost circuit 21 also includes multiple switching elements such as IGBTs. The housing case 20 is made of metal.

Figure 2 is a perspective view showing the PCU 3. The housing case 15 is formed in a substantially rectangular parallelepiped shape. The housing case 15 includes a bottom surface 22, a top surface 23, and a peripheral surface 24. The bottom surface 22 is fixed to the transaxle 2. The peripheral surface 24 is disposed between the bottom surface 22 and the top surface 23. The peripheral surface 24 includes long sides 26 and 27, and short sides 28 and 29.

Figure 3 is a plan view showing the top surface 23 of the PCU 3. The top surface 23 is formed in a rectangular shape. The top surface 23 includes a pair of long sides 30, 31 and a pair of short sides 32, 33. The protrusion 25 is provided at the corner formed by the long side 30 and the short side 32.

Figure 4 is a perspective view showing the protrusion 25 and the configuration around the protrusion 25. The protrusion 25 is formed in an L-shape. The protrusion 25 includes a piece 36 extending along the long side 30 and a piece 37 extending along the short side 32. The protrusion 25 is formed to protrude from the top surface 23, and the protrusion 25 protrudes from the PCU 3 toward the boost converter 4. The protrusion 25 includes a top surface 35, which is located above the top surface 23.

Figure 5 is a plan view of the boost converter 4 and the PCU 3 when viewed from above the boost converter 4. In this embodiment 1, the boost converter 4 and the PCU 3 are approximately aligned when viewed in a plan view.

Figure 6 is an oblique view showing the PCU 3 and boost converter 4, and is an oblique view showing the protrusion 25 and the surrounding configuration.

The storage case 20 of the boost converter 4 includes a bottom surface 40. The bottom surface 40 is formed in a substantially rectangular shape. A gap 5 is formed between the top surface 23 of the storage case 15 and the bottom surface 40 of the storage case 20.

The outer periphery of the gap 5 opens outward. Openings 41, 42, 43, and 44 are formed on the outer periphery of the gap 5. Opening 41 is located on the long side 30 side, and opening 42 is located on the long side 31 side. Opening 43 is located on the short side 32 side, and opening 44 is located on the short side 33 side. Openings 41 and 42 are arranged in the first direction D1, and openings 43 and 44 are arranged in the second direction D2. The protrusions 25 are formed on openings 41 and 43, which are the outer periphery of the gap 5.

Here, the first direction D1 is the propagation direction of the traveling sound wave when air column resonance occurs between the opening portion 41 and the opening portion 42. The second direction D2 is the propagation direction of the traveling sound wave when air column resonance occurs between the opening portion 43 and the opening portion 44. In the present embodiment 1, the first direction D1 and the second direction D2 intersect at right angles to each other.

Figure 7 is a cross-sectional view taken along line VII-VII in Figure 5. In other words, it shows the protrusion 25 and the opening 41 as viewed in the first direction D1.

Here, in a state where the protrusion 25 is not provided, the length of the opening 41 in the second direction D2 when viewed in the first direction D1 is defined as "X". In a state where the protrusion 25 is not provided, the height of the opening 41 in the vertical direction (the direction in which the PCU 3 and the boost converter 4 are separated) is defined as "H". Here, in a state where the protrusion 25 is not provided, the area of the opening 41 projected in the first direction D1 is defined as the opening area S1.

The length of the protrusion 25 in the second direction D2 when viewed in the first direction D1 is defined as "L1". The height of the protrusion 25 in the height direction when viewed in the first direction D1 is defined as "H1". The projected area of the protrusion 25 in the first direction D1 is defined as the projected area S10.

In this embodiment 1, the "length L1" is "0.423X" and the "height H1" is "0.95H".

Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 5. In other words, the opening 43 and the protrusion 25 are viewed in the second direction D2.

When the protrusion 25 is not provided, the length of the opening 43 in the first direction D1 when viewed in the second direction D2 is defined as "Y". When the protrusion 25 is not provided, the height of the opening 43 is defined as "H".

The area of the opening 43 projected in the second direction D2 is defined as the opening area S2. The area of the protrusion 25 projected in the second direction D2 is defined as the projected area S11.

The length of the protrusion 25 in the first direction D1 when viewed in the second direction D2 is "L2". The height of the protrusion 25 in the vertical direction when viewed in the second direction D2 is "H1". Here, "length L2" is "0.437Y".

In the equipment unit 1 configured as described above, the PCU 3 may vibrate when the transaxle 2 is driven.

Furthermore, "height H", "height H1", "length X", "length Y", "length L1" and "length L2" satisfy the following formula (1).
100×{(L1+L2)×H1}/{(X+Y)×H}>15(%)...(1)
The above formula (1) can be transformed into the following formula (2).
100×{projected area S10+projected area S11}/{(opening area S1+opening area S2}>15(%)...(2)
8, if the vertical distance between the top surface 35 of the protrusion 25 and the bottom surface 40 of the storage case 20 is "GP1", then GP1 is 0.05H. For example, the distance GP1 is 1.5 mm or less.

In the equipment unit 1 and transaxle 2 configured as described above, the rotating electric machines 11, 12 and the transmission 13 housed in the transaxle 2 are driven, causing the housing case 10 to vibrate. The vibration of the housing case 10 is transmitted to the PCU 3, causing the housing case 15 to vibrate. When the housing case 15 vibrates, air column resonance may occur in the gap 5.

Here, we will first explain the case where air column resonance occurs in the equipment unit 1A according to the comparative example. Then, we will compare the equipment unit 1A according to the comparative example with the equipment unit 1 according to the first embodiment.

Figure 9 is a perspective view showing an equipment unit 1A according to a comparative example. The equipment unit 1A does not have a protrusion 25. Other than the protrusion 25, the configuration of the equipment unit 1A is the same as that of the equipment unit 1.

The equipment unit 1A includes a PCU 3A and a boost converter 4A. The PCU 3A includes a housing case 15A, and the boost converter 4A includes a housing case 20A. A gap 5A is formed between the housing case 20A and the housing case 15A.

When air column resonance occurs within gap 5A, it mainly consists of the first mode air column resonance and the second mode air column resonance described below.

In the first mode, air column resonance occurs between opening portion 41A and opening portion 42A. In the first mode, opening portion 41A and opening portion 42A become the "belly portion" of the air column resonance. In the first direction D1, the center of gap 5A becomes the "node portion" of the air column resonance. In this air column resonance, the propagation direction of the traveling sound wave is the first direction D1.

Here, since the protrusion 25 is not provided in the equipment unit 1A, air column resonance occurs over the entire surface of the opening 41A and the entire surface of the opening 42A.

In the second mode, air column resonance occurs between opening portion 43A and opening portion 44A. In the second mode, air column resonance occurs between opening portion 43A and opening portion 44A. In the second mode, opening portion 43A and opening portion 44A become the "belly portion" of the air column resonance. And, in the second direction D2, the center of gap 5A becomes the "node portion" of the air column resonance. In the second mode, the traveling direction of the traveling sound wave is the second direction D2.

Here, since the protrusion 25 is not provided in the equipment unit 1A, air column resonance occurs over the entire surface of the opening 43A and the entire surface of the opening 44A.

Next, we will explain the case where the first mode of air column resonance occurs in the equipment unit 1 according to the first embodiment.

In this embodiment 1, as shown in Figures 6 and 7, a protrusion 25 is provided. The distance GP1 between the upper surface 35 of the protrusion 25 and the bottom surface 40 of the storage case 20 is 1.5 mm or less. Therefore, in this portion, viscous resistance is high and air column resonance is unlikely to occur.

In FIG. 5, the portion of the opening 41 that is located closer to the short side 33 than the protrusion 25 is defined as opening region R1. The portion of the opening 42 that faces opening region R1 in the first direction D1 is defined as opening region R2.

When air column resonance of the first mode occurs, air column resonance occurs between the opening region R1 and the opening region R2. In this case, the traveling direction of the traveling sound wave when air column resonance occurs is the first direction D1.

When viewed from the first direction D1, the opening area of the opening region R1 is smaller than the opening area (opening area S1) of the opening portion 41A shown in FIG. 9. Similarly, when viewed from the first direction D1, the opening area of the opening region R2 is smaller than the opening area (opening area S2) of the opening portion 42A shown in FIG. 9.

As a result, when first mode air column resonance occurs, the noise generated from equipment unit 1 is smaller than the noise generated from equipment unit 1A.

Next, the air column resonance in the second mode will be described.
8, the distance GP1 between the top surface 35 and the bottom surface 40 of the protrusion 25 is 1.5 mm or less. Therefore, the viscous resistance in this portion is high, and air column resonance is unlikely to occur in this portion.

In FIG. 5, the portion of the opening 43 that is located closer to the long side 31 than the protrusion 25 is defined as opening region R3. In the second direction D2, the portion of the opening 44 that faces opening region R3 is defined as opening region R4.

When second mode air column resonance occurs, air column resonance occurs between opening region R3 and opening region R4.

When viewed from the second direction D2, the opening area of the opening region R3 is smaller than the opening area of the opening portion 43A shown in FIG. 9. Similarly, the opening area of the opening region R4 is smaller than the opening area of the opening portion 44A.

As a result, when second mode air column resonance occurs, the noise generated from equipment unit 1 is kept lower than the noise generated from equipment unit 1A.

In this embodiment 1, the configuration is as shown in the above formulas (1) and (2). Specifically, when the protrusion 25 and the gap 5 are projected in the direction of travel of the traveling sound wave of the air column resonance (first direction D1 and second direction D2), the projected area of the protrusion 25 (projected area S10 + projected area S11) is 15% of the opening area of the gap 5 (opening area S1 + opening area S2).

By forming the protrusion 25 in this way, it is possible to suppress the occurrence of air column resonance within the protrusion 25.

In the present embodiment 1, the protrusion 25 is formed in an L-shape and includes both the arm 36 and the arm 37, but the protrusion 25 may be shaped so that only one of the arm 36 and the arm 37 is provided.

For example, even when only the piece portion 37 is provided, the projection area S11 of the protrusion 25 is 15% or more of the opening area S2 of the opening portion 43. Therefore, the area where the second mode air column resonance occurs can be sufficiently reduced, and noise can be effectively reduced.
(Embodiment 2)
The equipment unit 1B according to the second embodiment will be described with reference to Fig. 10 etc. The equipment unit 1B has substantially the same configuration as the equipment unit 1, except for the shape of the protrusions.

Figure 10 is a perspective view showing a portion of equipment unit 1B according to embodiment 2. Equipment unit 1B includes PCU 3B and boost converter 4B. Boost converter 4B is substantially the same as boost converter 4 in embodiment 1.

PCU3B includes a housing case 15B. A protrusion 25B is formed on an upper surface 23B of the housing case 15B. The protrusion 25B is formed at the corners of the long side 30B and the short side 32B. The protrusion 25B includes an upper surface 35B and a curved surface 45B.

A gap 5B is formed between the boost converter 4 and the PCU 3. The gap 5B includes an opening portion 41B and an opening portion 42B arranged in the first direction D1, and an opening portion 43B and an opening portion 44B arranged in the second direction D2.

Figure 11 is a plan view showing equipment unit 1B. Note that in this second embodiment, PCU 3B and boost converter 4B are also arranged to coincide.

Here, the portion of opening portion 41B located closer to short side 33B than protrusion 25B is defined as opening region R1B. The portion of opening portion 43B located closer to long side 31B than protrusion 25B is defined as opening region R3B. The portion of opening portion 42B facing opening region R1B is defined as opening region R2B. The portion of opening portion 44B facing opening region R3B is defined as opening region R4B.

In addition, air column resonance may occur in gap 5B. In this case, air column resonance occurs mainly between opening region R1B and opening region R2B, and between opening region R3B and opening region R4B.

When air column resonance occurs between opening region R1B and opening region R2B, the propagation direction of the traveling sound wave is the first direction D1. When air column resonance occurs between opening region R3B and opening region R4B, the propagation direction of the traveling sound wave is the second direction D2.

Figure 12 is a cross-sectional view taken along line XII-XII in Figure 11. In other words, Figure 12 shows the protrusion 25B and the opening 41B as viewed in the first direction D1.

Here, when the protrusion 25B is not provided, the length of the opening 41B in the second direction D2 when viewed in the first direction D1 is defined as "length XB."

When the protrusion 25B is not provided, the vertical height of the opening 41B is defined as "height HB." When the protrusion 25B is not provided, the projected area of the opening 41B projected in the first direction D1 is defined as projected area S1B.

The length of the protrusion 25B in the second direction D2 when viewed in the first direction D1 is defined as "L1B". The height of the protrusion 25 in the height direction when viewed in the first direction D1 is defined as "H1B". The projected area of the protrusion 25B in the first direction D1 is defined as the projected area S10B.

In this embodiment 1, "length L1B" is "0.423XB" and "height H1B" is "0.95H".

Figure 13 is a cross-sectional view taken along line XIII-XIII in Figure 10. In other words, it shows the opening 43B and the protrusion 25B as viewed in the second direction D2.

When the protrusion 25B is not provided, the length of the opening 43B in the first direction D1 when viewed in the second direction D2 is defined as "YB". When the protrusion 25 is not provided, the height of the opening 43 is defined as "HB".

The area of the opening 43B projected in the second direction D2 is defined as the opening area S2. The area of the projection of the protrusion 25B projected in the second direction D2 is defined as the projection area S11B.

The length of the protrusion 25B in the first direction D1 when viewed in the second direction D2 is "L2B". The height in the vertical direction when viewed in the second direction D2 of the protrusion 25B is also "H1B". Here, "length L2B" is "0.437YB".

Furthermore, "height HB", "height H1B", "length XB", "length YB", "length L1B" and "length L2B" satisfy the following formula (3).
100×{(L1B+L2B)×H1B}/{(XB+YB)×HB}>15(%)...(3)
10, if the vertical distance between the top surface 35B of the protrusion 25B and the bottom surface 40B of the housing case 20B is "GP1B", then GP1B is 0.05HB. For example, the distance GP1B is 1.5 mm or less.

In the equipment unit 1B configured as described above, air column resonance may occur within the gap 5B. For example, in FIG. 10, air column resonance may occur between the opening region R1B and the opening region R2B.

In FIG. 11, the opening area of opening region R1B is smaller than that of opening portion 41B, and the opening area of opening region R2B is smaller than that of opening portion 42B. Therefore, the noise generated in equipment unit 1A shown in FIG. 9 can be reduced in equipment unit 1B as well.

In equipment unit 1B, air column resonance may also occur between opening region R3B and opening region R4B. In this case, the opening area of opening region R3B is smaller than the opening area of opening portion 43B, and the opening area of opening region R4B is smaller than the opening area of opening portion 44B. Therefore, the noise generated in equipment unit 1B can be kept smaller than the noise generated in equipment unit 1A.

Figure 14 shows the increase in sound volume when air column resonance occurs in equipment units with various modifications to the shape of the protrusion 25B.

In the graph shown in FIG. 14, the horizontal axis indicates the frequency (KHz) of air column resonance, and the vertical axis indicates the sound pressure increase due to air column resonance. Here, the left side of the above formula (3) is the projection area ratio PR of the protrusion 25B.

In FIG. 14, the graph line GL1 shows the results for an equipment unit in which the protrusion 25B is not formed. The projected area ratio PR1 of this equipment unit is 0(%).

Graph line GL2 shows the results for an equipment unit with a projected area ratio PR2 of 12%. Graph line GL3 shows the results for an equipment unit with a projected area ratio PR3 of 26%. Graph line GL4 shows the results for an equipment unit with a projected area ratio PR4 of 41%.

In Figure 14, it can be seen that for each equipment unit, the sound pressure increase (dB) is highest at a frequency of P1 (KHz). In other words, it can be seen that the air column resonance frequency of each equipment unit is P1 (KHz).

Figure 15 is a graph showing the peak increase (dB) at the air column resonance frequency P1. In the graph shown in Figure 15, the horizontal axis shows the projected area ratio (%), and the vertical axis shows the peak increase (dB).

In FIG. 15, peak point PP1 indicates the peak point of an equipment unit where the projected area ratio PR1 is 0%. Peak point PP2 is the peak point of an equipment unit where the projected area ratio PR2 is 12%. Peak point PP3 is the peak point of an equipment unit where the projected area ratio PR3 is 26%. Peak point PP4 is where the projected area ratio PR4 is 41%.

As is clear from Figure 15, when the projected area ratio PR is 15% or more, the peak point can be kept small.

Furthermore, it can be seen that the peak point can be kept small when the projected area ratio PR is 26% or more. It can also be seen that the peak point can be kept even smaller by setting the projected area ratio PR to 41%.

That is, it is understood that the peak point can be kept small by setting the projected area ratio to at least 15% to 41%.
(Embodiment 3)
A device unit 1C according to a third embodiment will be described with reference to Fig. 16 and other figures. The device unit 1C has the same structure as the device unit 1, except for the shape of the protrusions.

Figure 16 is a perspective view showing a part of equipment unit 1C according to embodiment 3. Equipment unit 1C includes PCU 3C and boost converter 4C. Boost converter 4C is substantially the same as boost converter 4 in embodiment 1.

The PCU3C includes a housing case 15C. A protrusion 25C is formed on the upper surface 23C of the housing case 15C. The protrusion 25C is formed in a ring shape along the outer periphery of the upper surface 23C.

Figure 17 is a plan view showing equipment unit 1C. Note that in equipment unit 1C, PCU 3C and boost converter 4C are also arranged to coincide.

Figure 18 is a cross-sectional view taken along line XVIII-XVIII in Figure 17. Figure 19 is a cross-sectional view taken along line IX-IX in Figure 17.

Here, if the vertical distance between the top surface 35C of the protrusion 25C and the bottom surface 40C of the storage case 20C is "distance GP1C," then distance GP1C is 1.5 mm or less. Preferably, distance GP1C is 0.6 mm or more and 1.5 mm or less.

By setting the distance GP1C to 1.5 mm or less, the viscous resistance of the air increases, making it difficult for air column resonance to occur within the gap 5C. Note that if the distance GP1C is set to less than 0.6 mm, there is a risk that the protrusion 25C will interfere with the boost converter 4C when the PCU 3C vibrates.

Figure 20 is a graph showing the increase in sound volume when air column resonance occurs in equipment units with various modifications to the shape of the protrusion 25C.

In Figure 20, the graph line GL5 shows the case where the protrusion 25C is not provided. In this case, the vertical distance between the PCU 3 and the boost converter 4C is 3 mm.

Graph line GL6 shows an equipment unit including a protrusion 25C formed so that the distance GP1C is 1.2 mm. Graph line GL7 shows an equipment unit including a protrusion 25C formed so that the distance GP1C is 0.6 mm. Air column resonance occurs at the air column resonance frequency P2 in each equipment unit.

As is clear from Figure 20, by setting the distance GP1C to 1.5 mm or less, it is possible to reduce the increase in sound pressure when air column resonance occurs.

The distance GP1C is set to 0.6 mm or more and 1.2 mm or less. If the distance GP1C is set to 1.2 mm or less, the air viscosity will be high and air column resonance will be less likely to occur.

On the other hand, if distance GP1C is made smaller than 0.6 mm, there is a risk that protrusion 25C will interfere with boost converter 4C when PCU 3C vibrates.
(Embodiment 4)
A device unit 1D according to the fourth embodiment will be described with reference to Fig. 21 etc. The device unit 1D has the same configuration except for the protrusions.

Figure 21 is a perspective view showing a portion of equipment unit 1D. Equipment unit 1D includes a PCU 3D and a boost converter 4D.

The PCU3D includes a housing case 15D. The upper surface 23D of the housing case 15D is formed as a flat surface, and no protrusions are formed on the upper surface 23D.

A gap 5D is formed between the bottom surface 40A and the top surface 23D. Openings 41D, 42D, 43D, and 44D are formed on the outer periphery of the gap 5D. Openings 41D and 42D are arranged in the first direction D1, and openings 43D and 44D are arranged in the second direction D2.

The distance GP1D between the gap 5D and the openings 41D, 42D, 43D, and 44D in the arrangement direction (vertical direction) of the storage case 20D and the storage case 15D is 0.6 mm or more and 1.5 mm or less.

Figure 22 is a graph showing the increase in sound volume when air column resonance occurs when the distance GP1D between the housing case 20D and the housing case 15D is changed in various ways. The graph line GL8 shows the case where the distance GP1D is 3 mm. The graph line GL9 shows the case where the distance GP1D is 5 mm.

Graph line GL10 shows the case where distance GP1D is 6 mm. Graph line GL11 shows the case where distance GP1D is 8 mm. Graph line GL12 shows the case where distance GP1D is 1 mm. In the example shown in FIG. 21, the air column resonance frequency is "P2."

Figure 23 is a graph showing the peak increase (dB) at the air column resonance frequency P2. In the graph shown in Figure 23, the horizontal axis shows the distance GP1D, and the vertical axis shows the peak increase (dB).

Here, peak point PP8 indicates the peak point when distance GP1D is 3 mm. Peak point PP9 indicates the peak point when distance GP1D is 5 mm. Peak point PP10 indicates the peak point when distance GP1D is 6 mm. Peak point PP11 indicates the peak point when distance GP1D is 8 mm. Peak point PP12 indicates the peak point when distance GP1D is 1 mm.

As is clear from FIG. 23, it can be seen that the resonance sound generated in the gap 5D can be reduced by setting the distance GP1D to 0.6 mm or more and 1.5 mm or less at the air column resonance frequency P2. Note that when the distance GP1D is set to 1.5 mm, the resonance sound is smaller than the resonance sound at the peak point PP11. This is because when the distance GP1D is smaller than 0.6 mm, the housing case 20D and the housing case 15D come into contact with each other even if they vibrate slightly. Note that the resonance sound can be further reduced by setting the distance GP1D to 0.6 mm or more and 1.2 mm or less. Note that the resonance sound can be further reduced by setting the distance GP1D to 0.6 mm or more and 1.0 mm or less.
(Embodiment 5)
In the above first to third embodiments, the protrusions are formed on the storage cases 15, 15B, and 15C. However, the protrusions may be formed on the storage case 20.

Figure 24 is a perspective view showing an equipment unit 1E according to embodiment 5. Figure 25 is a cross-sectional view showing the equipment unit 1E. In this equipment unit 1E, a protrusion 25E is formed on the bottom surface 40E of the storage case 20E. The shape of the protrusion 25E is substantially the same as the protrusion 25 in embodiment 1. The equipment unit 1E provided with this protrusion 25E can also achieve the same effects as the equipment unit 1 according to embodiment 1.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

1, 1A, 1B, 1C, 1D, 1E Equipment unit, 2 Transaxle, 4, 4A, 4B, 4C, 4D Boost converter, 5, 5A, 5B, 5D Gap, 10, 15, 15A, 15B, 15C, 15D, 20, 20A, 20B, 20C, 20D, 20E Storage case, 11, 12 Rotating electric machine, 13 Transmission, 16 Inverter, 21 Boost circuit, 22, 40, 40A, 40B, 40C, 40E Bottom surface, 23, 23B, 23C, 23D, 35, 35B, 35C Top surface, 24 Circumferential surface, 25, 25B, 25C, 25E Protrusion, 26, 27 Long side surface, 28, 29 Short side surface, 30, 30B, 31, 31B Long side, 32, 32B, 33, 33B Short side, 36, 37 One side, 41, 41A, 41B, 41D, 42, 42A, 42B, 42D, 43, 43A, 43B, 43D, 44, 44A, 44B, 44D Opening, 45B Curved surface, D1 First direction, D2 Second direction, GL1, GL2, GL3, GL4, GL5, GL6, GL7, GL8, GL9, GL10, GL11, GL12 Graph line, GP1B, GP1, GP1C, GP1D Distance, H, H1, H1B, HB Height, L1B, L1, L2, L2B, X, XB, Y, YB Length, P1, P2 Air column resonance frequency, PP1, PP2, PP3, PP4, PP8, PP9, PP10, PP11, PP12 Peak point, PR, PR1, PR2, PR3, PR4 Projected area ratio, R1, R1B, R2, R2B, R3B, R3, R4B, R4 Opening area, S1B, S10, S10B, S11, S11B projected area, S1, S2 opening area.

Claims (1)

a first device that vibrates;
a second device disposed with a gap between the first device and the second device;
A protrusion is disposed on the outer periphery of the gap and is formed so as to narrow the gap;
An equipment unit comprising:
The direction in which a traveling sound wave of air column resonance generated in the gap propagates in a state in which the protruding portion is not provided is defined as a propagation direction,
When the protrusion is not provided, an area of the gap projected in the propagation direction is defined as an opening area;
If the area of the protrusion when projected in the propagation direction is defined as a protrusion area,
The protruding area is 26% or more and 41% or less of the opening area,
The protrusion is formed so as to protrude from the first device toward the second device, and a gap between the protrusion and the second device is 1.5 mm or less.