The present invention relates to an electric heating device and an electric vehicle, and more particularly to an electric heating device that is suitable as a heating device for electric vehicles, and an electric vehicle provided with the heating device.
Conventionally, heating devices for vehicles generally utilize engine exhaust heat. However, electric vehicles (EV), use of which is expected to explosively spread in future, cannot use the engine exhaust heat. Therefore, an electric heating device using a battery power supply as an energy source and having good performance is desired.
Electric heating devices used with electric vehicles are roughly classified into heating devices using a heat pump system and heating devices using a ceramic heater. As a ceramic heater, a ceramic heater using an air heating system and a ceramic heater using a water heating system are known. Heating devices using a heat pump system for use with electric vehicles are disclosed, for example, in Japanese Unexamined Patent Publication Nos. 9 (1997)-118126, 11 (1999)-105537 and 2000-033916 (hereinafter, Patent Documents 1, 2 and 3, respectively).
Conventional electric heating devices using a heat pump system or a ceramic heater have the following drawbacks to be overcome.
The first drawback is that the device configuration is complicated since the heating element (heat source) and the fan are provided separately. The second drawback is that the upper limit of the temperature of the heat source is a relatively low temperature of around 350° C. and this may often result in a large heat source. The third drawback is that, since the heat source typically involves wiring and piping, it is not easy to attach and remove the heat source onto and from a vehicle and this makes maintenance of the device difficult.
In view of the above-described circumstances, the present invention is directed to providing an electric heating device that is suitable as a heating device for electric vehicles, and has a simple configuration and a novel structure wherein a heat source and a fan are integrally formed.
In order to achieve the above-described object, the invention is further directed to providing an electric heating device that facilitates size reduction of the heat source since the upper limit of the heat source temperature is relatively high, and facilitates attachment and removal of the heat source since the heat source does not involve wiring and piping, thereby facilitating maintenance of the device.
The invention is also directed to providing an electric vehicle provided with the above-described electric heating device.
The above-described objects of the invention are accomplished by an electric heating device including: an electric motor including a disk-shaped stator that includes a plurality of stator coils arranged along a circumferential direction to generate a rotating magnetic field, and a disk-shaped rotor that includes a plurality of one-turn coils disposed correspondingly to the stator coils and a soft magnetic metal plate disposed on an opposite side of the one-turn coils from the stator and supporting the one-turn coils, the disk-shaped rotor being rotatably driven by the rotating magnetic field; and a fan secured to the soft magnetic metal plate on a side thereof opposite from the one-turn coils and including a vane wheel that has a plurality of vanes and rotates integrally with the rotor.
The electric vehicle of the invention includes the above-described electric heating device of the invention.
In the electric heating device of the invention (which may hereinafter also be referred to simply as “heating device”), the rotor forming the heat source and the fan for generating airflow that is heated by heat from the heat source are integrally disposed, thereby simplifying the device configuration.
In the heating device of the invention, a relatively high upper limit of the temperature of the rotor forming the heat source can be set, and this facilitates size reduction of the heat source while obtaining a high heating capability.
In the heating device of the invention, the rotating portion where the rotor forming the heat source and the fan for generating airflow are integrally formed does not require connection of wiring and piping. This facilitates attachment and removal of the rotating portion, which is the main portion to be checked during maintenance of the heating device, thereby providing a heating device that facilitates maintenance work, such as cleaning, filter replacement, etc.
In a case where the electric vehicle of the invention is provided with the above-described heating device for each of a plurality of airflow outlet ports in the vehicle, for example, heating temperature can be controlled for each part of the vehicle, and it is not necessary to provide an air duct etc., thereby allowing improvement of equipment layout efficiency in the vehicle.
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
The sirocco fan 30 forms a driven part of the induction electric motor and is rotatably supported by the casing 40 together with the rotor 20. The rotor 20 faces the stator 10 with a predetermined clearance (for example, an air gap of around 2 to 10 mm) therebetween.
When the heating device 100 of the above-described embodiment is operated, a rotating magnetic field is generated by applying the two-phase alternating currents with controlled frequency and voltage (electric power) to the coil groups of the coil row. By this rotating magnetic field, a circulating current is generated at the one-turn coils 22 of the rotor 20, and an eddy current is generated in the soft magnetic metal plate 21. Due to the thus generated circulating current, eddy current and rotating magnetic field, a rotational driving force is applied to the rotor 20 from the stator 10. Further, Joule heat is generated at the one-turn coils 22 and the soft magnetic metal plate 21 due to the circulating current and the eddy current. The sirocco fan 30 secured to the rotor 20 rotates together with the rotor 20, thereby taking in the airflow through the air inlet port 43 of the casing 40 and ejecting the airflow through the airflow ejection port 42. At this time, the airflow 52 taken into the casing 40 is heated by the Joule heat generated at the one-turn coils 22 and the soft magnetic metal plate 21 of the rotor 20 and becomes the warm airflow 53 to be ejected through the airflow ejection port 42. The airflow 53 is introduced into the interior of an electric vehicle, for example, to heat the interior of the vehicle.
It should be noted that an AC energy converter (induction motor) including a stator and a rotor that are similar to the stator 10 and the rotor 20 described above is disclosed in Japanese Unexamined Patent Publication No. 10 (1998)-098860, which is incorporated herein by reference.
In the prototype heating device of the example, each of the eight stator coils 11 of the induction electric motor was made of a copper wire with the number of turns of 30, which was wound on the ferrite magnetic core 12 having an outer diameter of 15 mm φ.
The soft magnetic metal plate 21 of the rotor 20 was made of an iron plate having an outer diameter of 150 mm and a thickness of 3.2 mm, and an aluminum disk having an outer diameter of 150 mm and a thickness of 2 mm was placed on the surface of the iron plate. The aluminum disk includes eight rectangular holes arranged at regular intervals in the circumferential direction, and surface portions of the soft magnetic metal plate 21 were embedded in the rectangular holes . With this structure, the rear surface of the rotor 20 was flat as a whole, and the eight one-turn coils 22 were provided. The air gap between the stator 10 and the rotor 20 was 2.6 mm. It should be noted that the size of the air gap can be selected in the range from about 2 mm to about 10 mm, for example. The vane wheel of the sirocco fan 30 had an outer diameter of 120 mm and a length of 53 mm in the axial direction. The vanes and the frame were made of aluminum having a thickness of 1 mm.
Two-phase alternating currents of 1.5 kHz with a phase difference of 90 degrees therebetween was applied to the coil row of the stator 10 of the prototype heating device. The characteristics shown in
It can be seen from the results of measurement that the heating temperature and the heating air velocity of the heating device of this example can be controlled by controlling the frequency and/or the voltage (electric power) For example, control of the frequency within the range from 0.2 kHz to 5 kHz and control of the electric power within the range from 50 W to 500 W were effective. In view of the materials used and the environmental conditions, the upper limit of the reached temperature of the rotor 20 is about 500° C.
In general, as a heating electric power for a vehicle, 2400 W is necessary for a small car and 3910 W is necessary for a large car (“Jidosha-Kogaku Handbook” (automotive engineering handbook)). In the case of the heating device used in the above-described example, a heating capability required for a heating device for a vehicle can be obtained by providing around 5 to 10 heating devices. In this case, necessity of providing an air duct, etc., can be eliminated by disposing the heating device at each airflow ejection port, for example, and improvement of equipment layout efficiency in a vehicle is expected. In this case, temperature setting can be made for each part of the interior of the vehicle. For example, a preferred heating temperature in the range from 24° C. to 28° C. for the upper body and a preferred heating temperature in the range from 28° C. to 32° C. for the lower body can be set independently.
In the case where the heating device of the invention is used as a heating device for a vehicle, an air gap may be provided between the stator 10 and the rotor 20, or an insulating material may be disposed between the stator 10 and the rotor 20. In the latter case, for example, the stator 10 may be embedded at a position inside the body of the vehicle where the stator 10 is not visible from the interior of the vehicle, and the rotor 20 maybe disposed at a position in the interior of the vehicle where the rotor 20 faces the stator 10. In this case, a number of stators may be disposed in advance, and rotors may be disposed to face only some of the stators that are disposed at suitable positions. This allows determining the number and the layout of the heating devices at the final stage of the production of a vehicle.
It should be noted that, in a case where a vehicle is provided with one heating device of the above-described embodiment, for example, the motor of the heating device of the above-described example is designed to have a large capacity accordingly. In this manner, a heating capability of the same level as that of a conventional heating device utilizing the engine exhaust heat can be provided.
In the heating device of the invention, the reached temperature of the rotor is preferably set in the range from about 200° C. to 500° C. Setting a high reached temperature of the rotor allows size reduction of the rotor, thereby allowing reducing the heat capacity of the rotor. In this case, the rise time of the heating device can be reduced, thereby allowing efficient heating of a vehicle.
As the induction electric motor of the heating device of the above-described embodiment, electric motors of the types disclosed in Japanese Unexamined Patent Publication No. 2010-154737 and Japanese Patent No. 4337961 (hereinafter, Patent Documents 4 and 5, respectively) are preferably usable. However, the electric motor used in the heating device of the invention is not limited to the induction electric motors disclosed in these patent documents, and may be any electric motor that has a structure where the rotor forming the heat source rotates together with the fan.
In the example shown in the above-described embodiment, the sirocco fan is employed as the fan. Employing the sirocco fan facilitates size reduction of the heating device. However, the fan used in the heating device of the invention is not necessarily limited to the sirocco fan, and any of various types of fans that can be secured to a rotor forming the heat source for generating Joule heat due to an eddy current and/or a circulating current and can rotate together with the rotor may be used. Further, while the example where the two-phase alternating currents are used to generate the rotating magnetic field has been shown, polyphase alternating currents of three or more phases may be used to generate the rotating magnetic field.
As described above, in the heating device of the invention, the rotor forming the heat source and the fan for generating airflow that carries heat from the heat source are integrally disposed, thereby simplifying the device configuration.
Further, in the heating device of the invention, the rotating portion where the rotor forming the heat source and the fan for generating airflow are integrally formed does not require connection of wiring and piping. This facilitates attachment and removal of the rotating portion, which is the main portion to be checked during maintenance of the heating device of an electric vehicle, or the like, thereby facilitating maintenance of the device.
The present invention has been described based on the preferred embodiment and the example thereof. However, the electric heating device of the invention is not limited to one having the arrangement disclosed in the above-described embodiment and the example, and heating devices with various modifications and changes made to the arrangement disclosed in the above-described embodiment and the example are also encompassed by the scope of the invention.
Number | Date | Country | Kind |
---|---|---|---|
2011-118904 | May 2011 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2012/003432 | 5/25/2012 | WO | 00 | 11/26/2013 |