JP7622595B2 - Contactless power receiving device - Google Patents

Description

This disclosure relates to a non-contact power receiving device.

In recent years, there has been progress in the development of contactless power supply devices that charge vehicles without contact. By positioning a power receiving device installed on the vehicle body above a power transmitting device installed on the road surface, power is transmitted contactlessly from the power transmitting device to the power receiving device, and power is supplied to the vehicle.

At this time, the coils of the power transmitting device and the power receiving device are heated by supplying power from the power transmitting device to the power receiving device. As a countermeasure against this heating, a configuration has been proposed in which a radiator fan or the like provided in the vehicle is driven to cool the power transmitting device and the power receiving device when power is being supplied (see Patent Document 1).

Meanwhile, the power receiving device is provided with a power receiving unit in which a power receiving coil and the like are arranged, and a shield made of a non-magnetic metal is arranged around the power receiving unit when viewed from the bottom of the vehicle, to prevent or suppress a decrease in power supply efficiency caused by the high-frequency magnetic field from the power transmitting device acting on the steel material constituting the vehicle body near the power receiving unit, and heat generation in the steel material constituting the vehicle body, etc.

JP 2016-152709 A

The shield is made of aluminum alloy, a non-magnetic metal material, for reasons of workability and cost. On the other hand, an exhaust pipe is installed on the bottom of the vehicle, and due to space restrictions, the exhaust pipe is sometimes installed near the shield.

The exhaust pipe becomes very hot when the vehicle is moving or immediately after it has stopped, and in some cases the temperature exceeds 500°C. Therefore, if the exhaust pipe is routed close to the shield, heat is transferred to the power receiving unit through the shield, which is made of an aluminum alloy that has a relatively high thermal conductivity compared to resins, etc., and the thermal stress of the power receiving unit increases.

There is room for improvement in this regard with contactless power receiving devices.

This disclosure has been made in consideration of the above, and aims to provide a non-contact power receiving device that suppresses the thermal stress acting on the power receiving unit via the shield.

The non-contact type power receiving device according to the first aspect includes a power receiving unit that is disposed on the bottom of the vehicle and includes a power receiving coil that is arranged opposite the power transmitting coil of a power transmitting device to enable power to be received in a non-contact manner, a lower case that is attached to the bottom of the vehicle, houses and supports the lower side of the power receiving unit, and has at least a portion of the power receiving unit that supports the power receiving coil portion in which the power receiving coil is arranged, formed from resin, and a shield that is supported by the lower case, is arranged to surround the lower case in a bottom view, and is formed from a non-magnetic metal.

In the first aspect, the vehicle is parked in a parking lot or the like, and the power receiving device provided at the bottom of the vehicle is positioned on the power transmitting device installed in the parking lot. By passing a high-frequency current through the power transmitting coil of the power transmitting device, a high-frequency magnetic field is applied to the power receiving coil of the power receiving device (power receiving unit), and power can be supplied from the power transmitting device to the power receiving device in a non-contact manner.

The lower case that houses the vehicle lower side of the power receiving unit is made of resin, so it does not impede the high-frequency magnetic field from acting on the power receiving coil.

In addition, a shield made of a non-magnetic metal is provided to surround the lower case in which the power receiving unit is housed when viewed from the bottom, which prevents or suppresses the high-frequency magnetic field generated by the power transmission coil of the power transmission device from acting on the vehicle body located above the shield and heating the vehicle body.

Furthermore, the exhaust pipe that extends from the front of the vehicle to the rear end of the vehicle is routed near the shield on the underside of the vehicle, and there is a risk that heat from the exhaust pipe will be conducted to the power receiving unit via the shield. In particular, if the shield is made of an aluminum alloy, which is a non-magnetic metal, from the standpoint of workability, etc., there is a risk that the thermal stress of the power receiving unit will increase due to heat conduction from the shield, which has a relatively high thermal conductivity compared to resin.

However, in this embodiment, the portion of the lower case that houses the vehicle lower side of the power receiving unit that supports the power receiving coil of the power receiving unit is made of resin, so the thermal conductivity of that portion of the lower case is relatively low compared to non-magnetic metals such as aluminum alloys. Therefore, heat conduction from the shield through the lower case to the power receiving unit is suppressed, and an increase in thermal stress on the power receiving unit can be suppressed.

The non-contact type power receiving device according to the second aspect is the non-contact type power receiving device according to the first aspect, in which the resin is non-conductive.

According to the second aspect, in the lower case, at least the portion that supports the power receiving coil portion of the power receiving unit is formed from a non-conductive resin.

Therefore, when the vehicle is stopped and the power receiving device provided at the bottom of the vehicle is positioned above the power transmitting device, a high-frequency current is passed through the power transmitting coil of the power transmitting device, causing a current to flow through the power receiving coil of the power receiving device (power receiving unit), and power can be supplied from the power transmitting device to the power receiving device in a non-contact manner.

At this time, the high-frequency magnetic field acts on the part of the lower case that supports the power receiving coil, but because the part that supports the power receiving coil is made of non-conductive resin, no current flows, and high power supply efficiency can be maintained.

The non-contact type power receiving device according to the third aspect is the non-contact type power receiving device according to the first or second aspect, in which the lower case has a portion that supports the portion of the power receiving unit other than the power receiving coil portion and is made of a non-magnetic metal.

According to the third aspect, the portion of the lower case that houses the lower half of the power receiving unit and that supports the portion of the power receiving unit other than the power receiving coil portion is made of a non-magnetic metal. Therefore, the high-frequency magnetic field from the power transmitting coil acting on the power receiving unit other than the power receiving coil, for example, on the rectifier, is prevented or suppressed from generating noise, etc.

The non-contact type power receiving device according to the fourth aspect is the non-contact type power receiving device according to the first or second aspect, in which the power receiving unit consists only of the power receiving coil section, and the lower case is entirely made of resin.

According to the fourth aspect, the power receiving unit is composed only of the power receiving coil section in which the power receiving coil is disposed, and the entire lower case supporting the power receiving coil section is made of resin. Therefore, since the entire lower case housing the vehicle lower side of the power receiving unit is made of resin, the high-frequency magnetic field is not impeded from acting on the power receiving coil (non-contact power supply).

The non-contact type power receiving device according to the fifth aspect is the non-contact type power receiving device according to any one of the first to fourth aspects, and further includes an upper case that is attached to the bottom of the vehicle, houses the upper side of the power receiving unit, is integrated with the lower case to store the power receiving unit, and is made of a non-magnetic metal.

According to the fifth aspect, the upper unit houses the upper side of the power receiving unit, and the upper unit and lower unit are integrated to store the power receiving unit inside the case. Here, a high-frequency magnetic field acts on the power receiving device when power is supplied, and there is a risk that part of this magnetic field will act on the steel material of the vehicle body located above the power receiving unit, causing the steel material of the vehicle body to heat up. However, according to this aspect, the upper unit that houses the upper side of the power receiving unit is made of a non-magnetic metal, so that the high-frequency magnetic field is prevented or suppressed from acting on the steel material of the vehicle body above the power receiving unit, and heating of the steel material of the vehicle body is prevented or suppressed.

The non-contact power receiving device according to the sixth aspect is a non-contact power receiving device according to any one of the first to fifth aspects, in which the shield is supported only by the lower case attached to the bottom of the vehicle body.

According to the sixth aspect, the shield is supported only by the lower case attached to the bottom of the vehicle body, so heat from the exhaust pipe is conducted from the shield to the power receiving unit only through the lower case. Therefore, even if the shield is made of an aluminum alloy or the like that has a relatively high thermal conductivity compared to resin, the lower case is made of a resin that has a relatively low thermal conductivity compared to metal, so that heat conduction from the lower case to the power receiving unit is suppressed. In other words, an increase in thermal stress on the power receiving unit is suppressed.

Note that a lower case "attached to the bottom of the vehicle" includes a lower case that is attached to the bottom of the vehicle via other members other than a shield.

The non-contact type power receiving device according to the seventh aspect is a non-contact type power receiving device according to any one of the first to sixth aspects, in which the non-magnetic metal is an aluminum alloy.

According to the seventh aspect, the non-magnetic metal is an aluminum alloy, which has excellent workability. Therefore, by forming the shield and upper case from an aluminum alloy, they can be easily processed.

The non-contact type power receiving device according to the eighth aspect is a non-contact type power receiving device according to any one of the first to seventh aspects, in which the resin is glass fiber reinforced plastic.

According to the eighth aspect, the resin used for the lower case is glass fiber reinforced plastic, which has strength and prevents or suppresses damage to the power receiving device disposed on the bottom surface of the vehicle caused by small stones or the like hitting the power receiving device from the road surface while the vehicle is traveling.

This disclosure can suppress thermal stress acting on the power receiving unit through the shield.

1 is a side view of a vehicle in which a non-contact power receiving device according to an embodiment is provided. 1 is a schematic bottom view of a vehicle in which a non-contact power receiving device according to an embodiment is provided; This is a cross-sectional view taken along line 3-3 in FIG. 2 is an exploded perspective view showing the power receiving unit, the lower case, and the upper case. FIG.

Below, a non-contact type power receiving device mounted on a vehicle according to one embodiment will be described with reference to Figures 1 to 4. In each figure, the arrow FR indicates the front of the vehicle, the arrow UP indicates the upper side of the vehicle, and the arrow LH indicates the left side of the vehicle.

As shown in Figures 1 and 2, the non-contact type power receiving device 10 (hereinafter referred to as "power receiving device 10") according to this embodiment is disposed on the bottom 14 of a vehicle 12. Therefore, the vehicle 12 can be parked in a parking lot or the like, and the power receiving device 10 can be placed above a power transmitting device 16 disposed on the road side of the parking lot. In this state, a high-frequency current is passed through the power transmitting coil of the power transmitting device 16, and a high-frequency magnetic field is generated, causing a current to flow through the power receiving coil of the power receiving device 10, making it possible to supply power from the power transmitting device 16 to the power receiving device 10 in a non-contact manner.

As shown in FIG. 3, the power receiving device 10 has a power receiving unit 20, a lower case 30, an upper case 40, and a shield 60.

As shown in FIG. 4, the power receiving unit 20 is formed in a substantially rectangular shape and is divided into a power receiving coil section 22 in which multiple power receiving coils are arranged, and a rectification section 24 in which multiple rectifiers are arranged.

The power receiving unit 20 is configured to be stored in the lower case 30 and the upper case 40, as shown in Figures 3 and 4.

As shown in FIG. 4, the lower case 30 has a recess 32 in which the lower half of the power receiving unit 20 is housed, and a flange portion 34 that extends outward from the upper end of the recess 32 and is formed around the recess 32.

The inside of the upper end of the vertical wall of the recess 32 is provided with multiple fastening parts 36 that protrude upward. The fastening parts 36 are formed with screw holes 36A for fastening to the upper case 40.

In addition, the flange portion 34 has multiple screw holes 34A for fastening to the shield 60.

The portion of the lower case 30 where the power receiving coil section 22 of the power receiving unit 20 is supported (the recess 32 and the flange section 34) is referred to as the first section 30A, and the portion where the rectifying section 24 is supported (the recess 32 and the flange section 34) is referred to as the second section 30B.

The first part 30A is made of a non-conductive resin material, such as GFRP (Glass Fiber Reinforced Plastics), so that the high-frequency magnetic field from the power transmission device 16 acts on the power receiving coil part 22 of the power receiving unit 20. Note that a screw hole 34A is formed only in the flange part 34 of the first part 30A.

On the other hand, the second part 30B is made of a non-magnetic metal material that blocks magnetic fields, such as an aluminum alloy (JIS A5052 is one example), because there is a risk of noise being generated in the rectifier when a high-frequency magnetic field from the power transmission device 16 acts on the second part 30B.

As shown in FIG. 3, the upper case 40 houses the upper half of the power receiving unit 20 and has a recess 42 that opens downward. A number of screw holes 42A (only two are shown in FIG. 4) are formed in the vertical wall of the recess 42. The fastening portion 36 of the lower case 30 is inserted into the recess 42 of the upper case 40, and a bolt (not shown) is screwed into the screw hole 36A of the fastening portion 36 and the screw hole 42A of the recess 42, and the lower case 30 and the upper case 40 are integrated by fastening them with a nut.

The entire upper case 40 is made of the same material, for example, aluminum alloy (JIS A5052 as an example).

Therefore, the lower half of the power receiving unit 20 is housed in the recess 32 of the lower case 30, the upper half is housed in the recess 42 of the upper case 40, and the lower case 30 and the upper case 40 are fastened together via the fastening portion 36, so that the power receiving unit 20 is stored and fixed inside the case.

As shown in FIG. 3, the upper case 40 has a plurality of mounting parts 46 (not shown in FIG. 4) extending outward from the upper end of the recess 42. The mounting parts 46 are fastened to a bracket 52 provided on the bottom 14 of the vehicle 12, thereby mounting the power receiving unit 20 to the bottom 14 of the vehicle 12.

Hereinafter, the power receiving unit 20 stored in this case (lower case 30, upper case 40) will be referred to as the stored power receiving unit 50.

As shown in FIG. 2, a flat shield 60 is disposed on the outside of the storage power receiving unit 50. As shown in FIG. 3, the shield 60 has a hole 62 formed in the center for accommodating the storage power receiving unit 50 (recess 32 of the lower case 30).

As shown in FIG. 3, the flange portion 34 of the lower case 30 and the shield 60 are overlapped by inserting the recessed portion 32 of the lower case 30 into the hole portion 62 of the shield 60. The shield 60 is attached to the storage power receiving unit 50 (lower case 30) by screwing a bolt 64 into the screw hole 34A of the flange portion 34 and a screw hole of the shield 60 (not shown) and fastening with a nut 66. In other words, the shield 60 is attached to the bottom 14 of the vehicle 12 via the storage power receiving unit 50. The fastening point between the lower case 30 and the shield 60 by the bolt 64 and the nut 66 is called the fastening portion 68.

The shield 60 is also made of a non-magnetic metal, for example, an aluminum alloy (JIS A5052 as an example) for ease of processing and cost.

As a result, as shown in FIG. 2, the shield 60 is arranged to surround the storage power receiving unit 50.

As shown in FIG. 2, an exhaust pipe 70 is disposed on the bottom 14 of the vehicle 12 from the front side of the vehicle toward the rear end of the vehicle, but is disposed in such a way that it wraps around to the right side of the vehicle to avoid the stored power receiving unit 50.

At this time, as shown in Figures 2 and 3, a portion of the exhaust pipe 70 is positioned between the shield 60 and the bottom 14 of the vehicle 12.

(Action)

The vehicle 12 equipped with the power receiving device 10 configured in this manner is parked in a parking lot or the like, and the power receiving device 10 (power receiving unit 20) is positioned above the power transmission device 16 installed on the road surface or the like of the parking lot.

In this state, when a high-frequency current is applied to the power transmission coil of the power transmission device 16, a current flows in the power receiving coil of the power receiving unit 20 due to the action of the high-frequency magnetic field. In other words, power is supplied from the power transmission device 16 to the power receiving device 10.

In this case, the first part 30A of the lower case 30 disposed below the power receiving unit 20 (the power transmitting device 16 side) is made of a non-conductive resin, for example, GFRP, so that the action of the high-frequency magnetic field from the power transmitting device 16 (power transmitting coil) on the power receiving coil part 22 of the power receiving unit 20 is not impeded. In other words, there is no impediment to the power supply from the power transmitting device 16 to the power receiving device 10 (power receiving unit 20).

In addition, the second part 30B of the lower case 30 is formed from a non-magnetic metal, such as an aluminum alloy, which prevents or suppresses the magnetic field acting from the power transmission device 16 from acting on the rectifier section 24 of the power receiving unit 20, thereby preventing or suppressing malfunctions such as noise generation in the rectifier.

On the other hand, as shown in Figures 2 and 3, the shield 60 arranged around the storage power receiving unit 50 is made of a non-magnetic metal, such as an aluminum alloy, so that the high-frequency magnetic field generated by the power transmission device 16 can be prevented or suppressed from acting on the steel material of the body of the vehicle 12 located above the shield 60 and heating the steel material of the body.

In addition, as shown in Figures 2 and 3, the exhaust pipe 70 is arranged close to the shield 60 at the bottom 14 of the vehicle 12 due to space restrictions. In particular, a portion of the exhaust pipe 70 is arranged to overlap (vertically overlap) with the shield 60 when viewed from the bottom.

Therefore, when the exhaust pipe 70 is hot while the vehicle 12 is running or stopped, heat is conducted from the exhaust pipe 70 to the lower case 30 via the shield 60 made of an aluminum alloy, which has a relatively high thermal conductivity compared to resin. Here, the first part 30A of the lower case 30 is made of GFRP, which has a relatively low thermal conductivity compared to metal, so that the thermal stress acting on the power receiving unit 20 housed in the case is reduced. In other words, heat is conducted from the exhaust pipe 70 to the power receiving unit 20 via the lower case 30, which is made of GFRP, which has a thermal conductivity of about 1/100 compared to the shield 60 made of an aluminum alloy, so that the thermal stress on the power receiving unit 20 is suppressed.

In particular, the lower case 30 is fastened to the shield 60 at the flange portion 34, separate from the fastening portion (fastening portion 36) with the upper case 40. In other words, the shield 60 is supported (fastened) only to the lower case 30. Therefore, the only heat conduction path from the shield 60 to the power receiving unit 20 is through the lower case 30, which is made of resin, and the heat conduction is suppressed, further suppressing the thermal stress of the power receiving unit 20.

In addition, the portion of the lower case 30 that corresponds to the power receiving coil section 22 of the power receiving unit 20 (first section 30A) is made of non-conductive resin, so when a high-frequency current is passed through the power transmitting coil of the power transmitting device 16 to pass current through the power receiving coil of the power receiving unit 20, current is prevented or suppressed from flowing through the first section 30A of the lower case 30, thereby reducing the power supply efficiency to the power receiving unit 20.

In particular, since the lower case 30 and the shield 60 are fastened via the fastening portion 68 provided only on the first portion 30A of the lower case 30, heat conduction from the shield 60 via the fastening portion 68 occurs only to the first portion 30A of the lower case 30 where the non-conductive resin (GFRP) is formed. Therefore, heat conduction from the lower case 30 to the power receiving unit 20 is suppressed, and an increase in thermal stress on the power receiving unit 20 is suppressed.

In addition, by forming the portion of the lower case 30 that supports the power receiving coil section 22 of the power receiving unit 20 (first portion 30A) from a non-conductive resin, such as GFRP, the lower case 30 can be ensured to have sufficient strength, and deformation and damage can be prevented or suppressed even if a stone or the like hits it from the road surface.

On the other hand, the part of the lower case 30 that supports the rectifier section 24 of the power receiving unit 20 (second part 30B) is made of a non-magnetic metal, such as an aluminum alloy, so that the high-frequency magnetic field from the power transmitting device 16 is shielded, preventing malfunctions in the rectifier, such as the generation of noise.

Furthermore, by forming the upper case 40 from a non-magnetic metal, such as an aluminum alloy, it is possible to prevent or suppress heating of the vehicle body (steel material) located above the upper case 40 due to the action of a high-frequency magnetic field when power is supplied.

(Additional explanation of the embodiment)

In this embodiment, the power receiving unit 20 has been described as having the power receiving coil section 22 and the rectifier section 24, but it may also be provided with only the power receiving coil section 22 (power receiving coil). In this case, the rectifier is provided in a location separate from the power receiving unit 20 (e.g., in the battery pack or inside the vehicle cabin). In this way, when only the power receiving coil is provided in the power receiving unit 20, the entire lower case 30 is formed of a non-conductive resin.

In addition, in this embodiment, GFRP has been described as an example of the material for the first part 30A of the lower case 30, but this is not limiting. Furthermore, a non-conductive resin is preferable, but other resins may also be used.

In addition, in this embodiment, the second portion 30B of the lower case 30 is preferably made of a non-magnetic metal, but is not limited to this.

In addition, in this embodiment, the second part 30B of the lower case 30, the shield 60, and the upper case 40 are described as being made of an aluminum alloy, but there is no particular limitation as long as they are non-magnetic metals. In addition, the second part 30B of the lower case 30, the shield 60, and the upper case 40 may each be made of a different metal.

In addition, in this embodiment, the lower case 30 and the upper case 40 are integrated via the fastening portion 36, but this is not particularly limited as long as the lower case 30 can be integrated with the upper case 40 separately from the shield 60.

Furthermore, in this embodiment, the upper case 40 is formed from a non-magnetic metal, but this is not essential. For example, the upper case 40 may be formed from resin. As described above, if only the power receiving coil is disposed in the power receiving unit 20 and the entire lower case 30 is formed from a non-conductive resin, it is conceivable that the lower case 30 is also formed from a non-conductive resin.

The present invention can be modified in various ways without departing from the spirit of the invention. It goes without saying that the scope of the invention is not limited to the above embodiment.

REFERENCE SIGNS LIST 10 Non-contact power receiving device 12 Vehicle 14 Bottom 20 Power receiving unit 22 Power receiving coil section 30 Lower case 30A First section (part supporting the power receiving coil section)
30B 2nd part (part supporting parts other than the power receiving coil part)
40 Upper case 60 Shield

Claims (8)

a power receiving unit that is disposed at the bottom of the vehicle and includes a power receiving coil that is disposed opposite a power transmitting coil of the power transmitting device to be able to receive power in a non-contact manner;
a lower case that is attached to a bottom of the vehicle, that houses and supports a vehicle lower side of the power receiving unit, and that supports at least a power receiving coil portion in the power receiving unit, the power receiving coil portion being made of resin;
a shield supported by the lower case and arranged to surround the lower case in a bottom view, the shield being made of a non-magnetic metal;
A non-contact power receiving device comprising: The non-contact power receiving device according to claim 1, wherein the resin is non-conductive. The non-contact type power receiving device according to claim 1 or 2, wherein the lower case is made of a non-magnetic metal and supports the parts of the power receiving unit other than the power receiving coil. The non-contact type power receiving device according to claim 1 or 2, wherein the power receiving unit consists only of the power receiving coil section, and the lower case is entirely made of resin. The non-contact type power receiving device according to any one of claims 1 to 4 further comprises an upper case that is attached to the bottom of the vehicle, houses the upper side of the power receiving unit, is integrated with the lower case to store the power receiving unit, and is made of a non-magnetic metal. A non-contact power receiving device according to any one of claims 1 to 5, wherein the shield is supported only by the lower case attached to the bottom of the vehicle. A non-contact power receiving device according to any one of claims 1 to 6, wherein the non-magnetic metal is an aluminum alloy. The non-contact power receiving device according to any one of claims 1 to 7, wherein the resin is glass fiber reinforced plastic.