JPH09261899A - Non-contact power transmission apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe and reliable non-contact power transmission apparatus that will not be burnt due to overcurrent or overheat even if the current or temperature of a coil for power transmission exceeds their allowable values. SOLUTION: An overcurrent protection device 6 as a transmission coil protecting means is placed either between a coil 3 for power transmission on the primary side and an external power supply or between a coil for power transmission on the secondary side and a load. The coil 3 for power transmission is serially connected with the overcurrent protection device 6 on an intermediate substrate 4. When the current of the coil 3 for power transmission exceeds a set value, the circuit current is interrupted. It is more favorable to install an overheat protection device instead of the overcurrent protection device 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety function and a protection function of a contactless power transfer device that transfers power in a contactless manner.

[0002]

2. Description of the Related Art Conventionally, a primary coil arranged on the primary side,
It consists of a pair of flat-cylindrical rotary transformers for power transmission that are opposed to a secondary coil arranged on the secondary side with a slight air gap. The primary coil supplies power to the secondary coil. A power supply is provided outside the secondary coil, and a load is provided on one of the secondary coils. The primary side is excited by a high frequency inverter or the like and a high frequency voltage is generated by electromagnetic induction to generate a secondary side. A contactless power transmission device has been proposed that transmits power to the load side of the contactlessly.

[0003]

However, in the above prior art, for example, when the gap of the transformer composed of the primary side and the secondary side becomes large during operation, a large current is supplied to the primary coil on the supply side. Flows, or when the temperature rises above the allowable temperature, magnetic saturation occurs in the core. As a result, there is a problem in that an overcurrent also flows in the secondary coil on the power receiving side and the coil is burned, which eventually causes a failure in the contactless power transmission device or the entire rotating device on the load side. Therefore, the present invention provides a contactless power transmission device having high safety and reliability without causing burnout due to overcurrent or overheating even when the power transmission coil has an allowable current value or an allowable temperature or higher. With the goal.

[0004]

In order to solve the above-mentioned problems, the present invention fits inside a cylindrical frame and houses a coil for power transmission in a ring-shaped groove provided inside. Contactless power transmission comprising a pair of magnetic material cores, which are arranged in parallel to each other on the primary side to which an external power source is connected and the secondary side to which a load is connected, with a slight gap therebetween, respectively. In the device, the coil on the primary side and the external power source or the secondary power source, which are arranged to face each other with a predetermined gap in the axial direction opposite to the gap between the magnetic cores and are provided inside the end surface of the frame, Side relay board for relaying connection between the coil and the load, resin filled in a space surrounded by the relay board, the frame, and the magnetic core, and series connection with the coil on the relay board Be done Both has a configuration in which a transmission coil protection means for interrupting the circuit current flowing through the coil when it detects an abnormality of the coil. The transmission coil protection means is provided between at least one of the coil and the power supply or between the coil and the load, and when the set current value of the coil is exceeded,
An overcurrent protection device that shuts off the circuit current between the coil and the power source or between the coil and the load may be provided, or instead of the overcurrent protection device, the overcurrent protection device is fixed in the resin and the coil When the set temperature is exceeded,
It is even better to provide an overheat protection device that shuts off the circuit.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a primary side of a contactless power transmission device equipped with an overcurrent protection device according to an embodiment of the present invention. FIG. 2 is an electric circuit diagram of the contactless power transmission device including the primary side and the secondary side shown in FIG. In the figure, 1 is a cylindrical frame, 2 is a magnetic core for power transmission fitted inside the frame 1, and 3 is a primary side housed in a ring-shaped groove inside the magnetic core. Power transmission coil, 31 is a secondary side power transmission coil, and 4 is a fixed-side transmission coil 3 provided inside the frame end, which is arranged to face the axial direction opposite to the void portion of the magnetic core 3. And a relay board for relaying the connection between the external power source or the transmission coil on the rotating side and the load, 5 is resin filled in the space surrounded by the relay board 4, the frame 1 and the magnetic core 2, and 6 is on the relay board. Is connected in series with the transmission coil, and shuts off the circuit current between the primary side power transmission coil 3 and the external power supply when an abnormality that exceeds the set current value of the transmission coil is detected. , 61 are power transmission coils 31 on the secondary side. An overcurrent protection device for interrupting a circuit current between loads, 7 is a power transmission coupler, 8 is a power source provided on the primary side, 9 is a load provided on the secondary side, 10 is a power transmission coil and a relay substrate 4 It is a lead wire that connects with. In a contactless power transmission device in which a pair of cylindrical magnetic cores having a power transmission coil housed in a ring-shaped groove are arranged to face each other with a gap, in FIG. The power transmission coil 3 is connected to the relay board 7 via a lead wire 10. Further, a circuit is arranged on the relay board 7 so as to be in series with the overcurrent protection device 6 and the power transmission coil 3. It is built in and has the same configuration on the secondary side as well. The power transmission coil 3 operates to automatically cut off the circuit current when an overcurrent flows between the power transmission coil 3 and the relay substrate 7. The overcurrent protection device connected in series with the power transmission coil 3 may be, for example, a fuse, or a bimetal whose contacts can be opened and closed by heat detection is fixed in the resin 5 instead of the overcurrent protection device. It may be used as an overheat protection device. The device for protecting these transmission coils may be provided at least either between the primary coil 3 and the power source 6 or between the secondary coil 31 and the load 9.

Next, the operation will be described. For example, even if the gap between a pair of magnetic cores facing each other becomes large during operation, a large current may flow in the primary coil for power transmission on the power supply side, or the power transmission core may exceed the allowable temperature due to some influence. Even if the fuse becomes very high, the fuse can detect overcurrent and automatically stop energizing. Also,
In bimetal, by detecting the temperature from the coil current, the circuit of the bimetal can be automatically shut off by opening and closing the contact of the bimetal, and the energization can be stopped. Therefore, with the configuration in which the transmission coil protection means is provided between the primary side coil and the power supply or between the secondary side coil and the load, the secondary coil on the power receiving side is overloaded due to the effect of magnetic saturation of the core. Even if an electric current flows, the problem that the coil is burnt does not occur, and the problem that the contactless power transmission device or the entire rotating device on the load side does not occur does not occur.

[0007]

As described above, according to the present invention, the power transmission coil does not suffer a burnout without a current exceeding the allowable current value or a temperature increase exceeding the allowable temperature. The effect of obtaining a reliable and reliable contactless power transmission device

[Brief description of drawings]

FIG. 1 is a sectional view of a contactless power transmission device showing an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of a contactless power transmission device showing an embodiment of the present invention.

[Explanation of symbols]

 1: Frame 2: Magnetic Core 3: Power Transmission Coil (Primary Side) 31: Power Transmission Coil (Secondary Side) 4: Relay Board 5: Resin 6: Overcurrent Protection Device (Primary Side) 61: Overcurrent protection device (secondary side) 7: Coupler for power transmission 8: Power supply 9: Load 10: Lead wire

Claims (4)

[Claims] 1. A primary body having a magnetic core which is fitted inside a cylindrical frame and has a coil for power transmission accommodated in a ring-shaped groove provided inside, and which is connected to an external power source. In a contactless power transmission device composed of a pair of the magnetic material cores, which are arranged in parallel to each other through a slight air gap on the secondary side connecting the load side and the load, an axis opposite to the air gap between the magnetic material cores. A relay board that is arranged to face each other with a predetermined gap in the direction and is provided inside the end surface of the frame and relays the connection between the primary side coil and the external power source or the secondary side coil and the load. A resin filled in a space surrounded by the relay board, the frame, and the magnetic core; and a coil that is connected in series with the coil on the relay board and detects an abnormality of the coil. A contactless power transmission device, comprising: a transmission coil protection means for interrupting a circuit current flowing through the coil. 2. The transmission coil protection means is provided between at least one of the coil and a power source or between the coil and a load.
The contactless power transmission device described. 3. The transmission coil protection means is provided with an overcurrent protection device that shuts off a circuit current between the coil and a power supply or between the coil and a load when the set current value of the coil is exceeded. The contactless power transmission device according to claim 1 or 2, characterized in that. 4. The transmission coil protection means is fixed in the resin in place of the overcurrent protection device, and
The contactless power transmission device according to claim 1 or 2, further comprising an overheat protection device that shuts off a circuit when the set temperature of the coil is exceeded.