JPH07322534A - Noncontact power transmission - Google Patents

Abstract

PURPOSE:To realize highly efficient transmission of power from the power supply side having the primary coil to the load side having the secondary coil by suppressing the leakage flux as low as possible in a noncontact power transmission. CONSTITUTION:The noncontact power transmission comprises primary coil section 1 and secondary coil section 2 separable from each other. The primary coil section 1 comprises a cylindrical core 11 having a cylindrical wall 12 and a rear wall 13, a core 14 planted on the rear wall 13, and a primary coil 10 wound around the inner peripheral surface of the cylindrical wall 12. The secondary coil section 2 comprises a disc core 21 having diameter equal to the outer diameter of the cylindrical core 11, and a secondary air-core coil 20 disposed in the center. When the primary coil section 1 and the secondary coil section 2 are combined, the cylindrical wall 12 and the core 14 substantially abut, at the forward end against the surface of the disc 21. The disc core 21, the cylindrical wall 12 and the rear wall 13 of the cylindrical core 11, and the core 14 establish an annular closed magnetic path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type power transmission device for a charger or electric equipment suitable for use around a water supply in a bathroom or the like.

[0002]

2. Description of the Related Art Conventionally, for example, a battery-applied electric device is provided with a charging electrode for charging, and at the time of charging, the electric device is mounted on a charger so that the charging electrode and the output electrode of the charger. It was generally configured to allow contact with. However, if the charging electrode and the output electrode are exposed on the surface of the device, the exposed electrode is likely to be deformed, causing a contact failure, and the device is particularly used around water. In this case, there is a risk that contact failure may occur due to corrosion, and further, a complicated waterproof structure must be adopted.

Therefore, in recent years, various electric devices have been proposed which make it possible to transmit electric power including charging without contact using electromagnetic induction. FIG. 7: is a figure which shows the structure of the electric power transmission part in the conventional non-contact type electric power feeder. Figure (a)-
In (d), 100 is a primary side housing on the power source side, 2
Reference numeral 00 denotes a secondary housing having a load, and in any case, the secondary housing 200 can be mounted on the upper surface of the primary housing 100 in a mounted state. Reference numeral 101 is a primary coil, and 201 is a secondary coil.

In FIG. 1A, the primary coil 101 is arranged at the upper inner end of the primary housing 100, and the secondary coil 202 has the same diameter as the primary coil 101 and is arranged on the lower inner surface of the secondary housing 200. They are installed so as to face each other in the mounted state. In FIG. (B), the upper surface of the primary-side housing 100,
The inner side of the diameter of the primary coil 101 is recessed, and the secondary side housing 200 is fitted in the recessed portion so that the secondary coil 201 is concentrically provided on the inner peripheral side of the primary coil 101. It is supposed to be arranged. In Figure (c),
A columnar core 102 extending vertically inward and outward is provided on the upper surface of the primary-side housing 100, while the secondary-side housing 200 is provided.
A recessed hole 202 into which the core 102 can be fitted is formed on the lower surface of the core 10, and the primary coil 101 and the secondary coil 201 are connected to the core 10.
It is designed to be magnetically coupled via 2. Figure (d)
Then, the protrusion 103 is formed on a part of the upper surface of the primary-side housing 100, and the columnar core 104 and the primary coil 10 are formed on this part.
On the other hand, a concave hole 203 into which the above-mentioned protruding portion 103 is fitted is formed on the lower surface of the secondary side housing 200, and the secondary coil 201 is wound around this concave hole 203. It is said that.

The primary coil 101 is connected to an oscillating circuit driven by a commercial power source, an alternating current is supplied to the primary coil 101 by this oscillating circuit, and an alternating magnetic flux is generated, and this magnetic flux chains the secondary coil 201. The alternating current induces alternating current power, which is further rectified and supplied to a load such as a battery or a motor that can be charged and discharged.

[0006]

By the way, the maximum value of the transmission power is determined by the leakage fluxes on the primary side and the secondary side. The leakage fluxes are primary and secondary when the shape of the core is a closed magnetic circuit. It is caused by the gap between:

FIG. 8 shows an equivalent circuit of the transformer. In the figure, L1 and L2 are leakage inductances on the primary side and the secondary side, and LM is the exciting inductance of the transformer. Here, for convenience of explanation, when the winding ratio of the primary side and secondary side coils is 1 and the value of LM is sufficiently larger than L1 and L2, the series inductance L with the load resistance R is , L = L1 + L2. From this, assuming that the primary input voltage is Vi, the secondary side output voltage Vo and the output power Po are expressed as in Equation 1.

[0008]

[Equation 1]

From the respective equations of the equation 1, it can be seen that the maximum load current and the maximum load power are obtained, and the values become larger as the value of L becomes smaller.

In the above-mentioned conventional structure of the power transmission portion, the core is provided only in a part of the magnetic path and the closed magnetic path is not formed, so that there is a limit in suppressing the generation of leakage magnetic flux. . Therefore, the series inductance L is inevitably a large value, and an effective high level cannot be obtained as the output power Po shown in Formula 1, which results in a very low transmission efficiency. From this, especially when the transmitted power is large, a configuration capable of supplying a large amount of power to the primary side of the transformer may be adopted.
The configuration on the primary side will increase in size, which will impair practicality and portability.

The present invention has been made in view of the above,
An object of the present invention is to provide a non-contact power transmission device that enables highly efficient power transmission from a power source side having a primary coil to a load side having a secondary coil.

[0012]

According to the present invention, a primary side portion having a primary coil connected to a pulsating current generation circuit and a secondary side portion having a secondary coil connected to a load can be separated from each other. In the power transmission device that supplies power from the primary side portion to the secondary side portion in a non-contact manner, one of the primary coil and the secondary coil is attached to the inner peripheral wall of the tubular core having one end opened. It is formed by winding, and the other coil is made smaller in diameter than the tubular diameter of the tubular core so as to stand upright on the plate-shaped core, and at least one of the tubular core and the plate-shaped core has a diameter smaller than that of the other coil. A columnar core having a small diameter is erected, and the primary side and the secondary side are combined so that the opening of the tubular core and the standing coil of the plate-shaped core face each other, and the magnetic field is closed. A path is formed and both coils are arranged on concentric axes. That (claim 1).

A coil may be wound around the core, and the wound coil may be connected in series or in parallel with the coil on the side where the core is provided (claim 2).

[0014]

According to the invention described in claim 1, when the primary side portion and the secondary side portion are combined, the center core, the plate core, the peripheral portion of the tubular core, and the closing surface portion of the tubular core are annularly formed. A nearly complete closed magnetic circuit is formed. When an on / off current or an alternating current is supplied from the pulsating current generation circuit to the primary coil, an alternating magnetic flux that links the primary coil is generated. This interlinkage magnetic flux is generated in the central core and is further concentrated in the closed magnetic circuit having a small magnetic resistance composed of the plate-shaped core and the cylindrical core, and the magnetic flux dispersion is effectively suppressed. Therefore, most of the generated magnetic flux will link the secondary coil at the secondary side, so the generation of leakage magnetic flux will be suppressed as much as possible, and the primary side power will be transmitted to the secondary side with high transmission efficiency. It

According to the second aspect of the invention, when the core is provided on the primary side, the number of generated magnetic flux increases, while
When the core is provided on the secondary side, the number of interlinkages with the generated magnetic flux is further increased, so that the transmission efficiency is increased in any case. Further, even when the core is provided in both the primary and secondary side parts, the generated magnetic flux and the number of interlinkages are increased, so that the transmission efficiency is improved as a whole.

[0016]

FIG. 6 is a circuit block diagram of an electric device to which the non-contact power transmission device according to the present invention is applied. In the figure, BA is a power supply unit and RL is a load unit, both of which are housed in a housing and have a separable structure.
The power supply unit BA and the load unit RL are so configured that they can be mounted so that the primary coil unit 1 and the secondary coil unit 2 that form the transformer T face each other. The primary coil unit 1 has a primary coil 10 and the secondary coil unit 2 has a secondary coil 20.

The mounting form may be, in addition to the mounting, a fitting in a semi-fixed state, a locking mechanism that is easy to operate, a locking member using an elastic material, and the like. Alternatively, it may be a fixed form such as a detachable screw. When the load section RL has a storage battery that can be charged and discharged and a motor that can be driven by this storage battery, since it is not in use when charging,
A mounting type can be adopted as the mounting form. When the load part RL is to carry out a required operation and operation while receiving power supply, the mounting type is preferable.

In the power supply unit BA, a rectifying current of a predetermined level is generated from a rectifying circuit 4 composed of a diode bridge or the like provided in the input line of the commercial power supply 3, a capacitor 5 for smoothing the rectified power, and DC power. Has an oscillation circuit 6 for
The output side of the oscillator circuit 6 is connected to both ends of the primary coil 10. As the oscillation circuit 6, a circuit adopting a known switching inverter can be applied. For example, a switching element is connected in series to the primary coil 10 of the transformer T, a capacitor 5 is connected to both ends of this series circuit, and a self-excited oscillation of this switching element is used to generate a switching pulse, and this pulse is switched. By supplying to the element, the current flowing through the primary coil 10 is repeatedly turned on and off to generate a pulsating current. Further, the oscillation circuit 6 may be one that directly generates a pulsating current having an AC waveform.

The load portion RL has a rectifying diode 7 connected to the secondary coil 20 and a load 8 capable of supplying rectified power. The load 8 may be any load that can be driven by load power, and is, for example, a motor or the like. The load 8 may be composed of a chargeable / dischargeable storage battery and a drive unit such as a motor that can be driven by receiving a discharge from the storage battery. In this case, the power supply unit BA acts as a charger.

Next, the operation of this circuit configuration will be described. When the commercial power supply 3 is turned on and the DC power rectified and smoothed by the rectifying bridge 4 and the capacitor 5 is supplied to the oscillating circuit 6, the oscillating circuit 6 starts the oscillating operation, and the primary current is repeatedly turned on and off in the primary coil 10. To supply. An alternating magnetic flux is generated in the primary coil 10 by this on / off current. In this state, when the load part RL is attached to the power source part BA, the alternating magnetic flux on the primary side links the secondary coil 20 to induce alternating-current power in the secondary coil 20. The AC power is rectified by the diode 7 and then supplied to the load 8 to start driving the load.

FIG. 1 is a perspective view showing a first embodiment of a non-contact power transmission device according to the present invention. FIG.
The primary coil portion 1 is cut out by 4 and the secondary coil portion 2 is shown in FIG. 2 is a vertical sectional view of FIG.
FIG. 6A shows a state in which the primary coil unit 1 and the secondary coil unit 2 are combined, that is, a state in which the load unit RL is attached to the power supply unit BA, and FIG. 6B shows the primary coil unit 1 and FIG. Indicates the secondary coil unit 2.

1 (a) and 2 (b), the primary coil portion 1 comprises a cylindrical core 11 made of a ferromagnetic material and having a predetermined diameter and a predetermined length, and the cylindrical wall 12 and the rear wall 13 are Each is formed to have a required thickness obtained from the relationship of magnetic flux density, magnetic resistance, and the like. The primary coil 10 is wound around the inner peripheral surface of the cylindrical wall 12 for a required number of turns. On the axis of the cylindrical core 11, a cylindrical core having a small diameter and also made of a ferromagnetic material is formed up to a height position corresponding to the cylindrical core 11.

Although not shown, both ends of the primary coil 10 are guided to the oscillation circuit 6 by crawling through fine holes or surfaces formed at appropriate positions of the cylindrical core 11.

In FIGS. 1 (b) and 2 (c), the secondary coil portion 2 is made of a ferromagnetic material, and the cylindrical core 11 is formed.
A disk core 21 having a diameter equal to the outer diameter and a predetermined thickness is provided, and a secondary coil 20 having a predetermined diameter and wound by the required number of air-core-like turns is erected at the center thereof. The secondary coil 20 has a coil diameter set between the diameter of the core 14 and the inner diameter of the cylindrical wall 12, specifically, the inner diameter of the primary coil 10 wound around the inner peripheral surface of the cylindrical wall 12. The dimension in the standing direction is the same as that of the core 14. By designing the shape of the secondary coil 20 as described above, when the primary coil portion 1 and the secondary coil portion 2 are combined,
As shown in FIG. 2A, the secondary coil 20 has a cylindrical core 1.
It fits inside 1 and reaches the rear wall 13,
The primary coil 10 and the secondary coil 20 can be superposed on the concentric axis, and the primary coil 10 and the secondary coil 20 are close to the surfaces of the respective disk cores 21 of the cylindrical wall 12 and the center core 14, and further the disk core 21. Since the diameter of the disk core 21 matches the diameter of the cylindrical core 11, the disk core 21, the cylindrical wall 12 of the cylindrical core 11, the rear wall 1
An annular closed magnetic circuit is formed from 3 and the core 14.

In FIGS. 2B and 2C, the cylindrical core 1
1, the broken lines covering the disk core 21 indicate the shapes of the casings of the power supply unit BA and the load unit RL, respectively. These casings are made of a non-magnetic resin material or the like, and are formed to be thin at least in the power transmission portion, and the gap length between each tip of the cylindrical wall 12 and the core 14 and the surface of the disc core 21 is minimized. It is small. By making the gap length smaller like this,
It is possible to approach a more complete closed magnetic circuit.

FIG. 3 is a perspective view showing a second embodiment of the non-contact power transmission device according to the present invention. FIG.
The primary coil portion 1a is cut out by 4 and the secondary coil portion 2a is shown in FIG. In the second embodiment, the core 14 of the first embodiment is provided on the secondary coil portion 2a side. That is, the disc 21 of the secondary coil portion 2a
A cylindrical core 22 having a required diameter is projectingly provided in the center of the surface of the secondary coil 20 for a required number of turns.
Is formed. Even if such a configuration is adopted, the first
As with the embodiment, it is possible to form a more complete closed magnetic circuit. Further, since the secondary coil 20 is wound around the core 22, the holding strength for the secondary coil 20 is increased.

FIG. 4 is a perspective view showing a third embodiment of the non-contact power transmission device according to the present invention. FIG.
The primary coil portion 1b is cut away by 4 and the secondary coil portion 2b is shown in FIG. 5A and 5B are vertical sectional views of FIG. 4, in which FIG. 5A shows the primary coil portion 1b and FIG. 5B shows the secondary coil portion 2b. The structure of the secondary coil portion 2b is basically the same as that of the first embodiment.

As shown in FIGS. 4 (a) and 5 (a), the primary coil portion 1b basically has the same structure as that of the first embodiment, and in addition to this structure, the core 14 A third coil 15 on the primary side is wound around the. The third coil 15 is connected to the primary coil 10 in series or in parallel. By providing the third coil 15 on the inner peripheral portion of the secondary coil 20 in a so-called sandwich winding shape, it is possible to further suppress the leakage magnetic flux and improve the magnetic coupling. Further, by connecting the third coil 15 in parallel to the primary coil 10, there is also an advantage that the power supplied from the power supply unit BA can be set large without causing an increase in size. The secondary coil 2
0 is the inner diameter of the primary coil 10 and the third coil 1
5 is set between the outer diameter and the outer diameter of 5, and the primary coil portion 1b and the secondary coil portion 2b can be combined.

In the present invention, the following modes can also be adopted. (1) In the first to third embodiments, the configurations of the primary coil portion and the secondary coil portion may be reversed, and even in this case, the closed magnetic circuit can be formed. (2) In the first embodiment, the core 14 is the primary coil portion,
For example, the secondary coil portions may be formed so as to be shared by, for example, ½ size or required size. (3) The cylindrical core 11 and the disc core 21 are not limited to the circular shape, and various shapes such as a polygonal shape can be adopted as long as the shapes of the both are the same. In this case, the mounting of the primary coil portion and the secondary coil portion can be performed by positioning at a predetermined angle. (4) The cores 14 and 22 are not limited to cylinders as long as they are columnar, and may be cylindrical columnar ones.

[0030]

As described above, according to the first aspect of the invention, one of the primary coil and the secondary coil is wound around the inner peripheral wall of the cylindrical core having one end open. Then, the other coil is made smaller in diameter than the tubular diameter of the tubular core and is erected on the plate core, and at least one of the tubular core and the plate core has a columnar shape having a diameter smaller than that of the other coil. A core is erected, and a closed magnetic circuit is formed in a state where the primary side portion and the secondary side portion are combined so that the opening of the cylindrical core and the standing coil of the plate-shaped core face each other. Since both coils are arranged on the concentric axis,
Even though it is a non-contact type, it is possible to suppress leakage flux as much as possible and transmit power from the primary coil to the secondary coil with high efficiency.

According to the second aspect of the present invention, a coil is wound around the core, and the wound coil is connected in series or in parallel with the coil on the side where the core is provided. Therefore, the strength of the coil can be maintained, the leakage magnetic flux can be suppressed, and the power supplied from the primary side can be increased.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a non-contact power transmission device according to the present invention, FIG. 1 (a) is a primary coil portion cut out by 1/4 in the circumferential direction, and FIG. The next coil part is shown.

FIG. 2 is a vertical cross-sectional view of FIG. 1, in which FIG. 2A shows a state in which a primary coil portion and a secondary coil portion are combined, that is, a state in which a load portion is attached to a power supply portion, and FIG. Coil portion, FIG. (C) shows a secondary coil portion.

FIG. 3 is a perspective view showing a second embodiment of the non-contact power transmission device according to the present invention, FIG. 3 (a) is a primary coil portion cut out by 1/4 in the circumferential direction, and FIG. The next coil part is shown.

FIG. 4 is a perspective view showing a third embodiment of the non-contact power transmission device according to the present invention, FIG. 4 (a) is a primary coil portion cut out by 1/4 in the circumferential direction, and FIG. The next coil part is shown.

FIG. 5 is a vertical cross-sectional view of FIG. 4, in which FIG.
FIG. 6B shows the secondary coil section.

FIG. 6 is a circuit block diagram of an electric device to which the non-contact power transmission device according to the present invention is applied.

FIG. 7 is a vertical cross-sectional view showing the structure of a power transmission portion in a conventional non-contact power supply device, and FIGS. 7 (a) to 7 (d) show respective types of configurations.

FIG. 8 is a circuit diagram showing an equivalent circuit of a transformer.

[Explanation of symbols]

 1, 1a, 1b Primary coil part 10 Primary coil 11 Cylindrical core 12 Cylindrical wall 13 Rear wall 14 Middle core 15 Third coil (winding coil) 2, 2a, 2b Secondary coil part 20 Secondary coil 21 Disc core 22 Core 6 Oscillation circuit (pulsating current generation circuit) 8 Load BA Power supply part (primary side part) RL Load part (secondary side part)

Claims (2)

[Claims] 1. A primary side part having a primary coil connected to a pulsating current generation circuit and a secondary side part having a secondary coil connected to a load are separable from each other, and the primary side is non-contacting. In a power transmission device that supplies electric power from a side portion to a secondary side portion, one of the primary coil and the secondary coil is formed by winding one coil around an inner peripheral wall of a cylindrical core having one end open, and the other. The coil is smaller than the tubular diameter of the tubular core and is erected on the plate core, and at least one of the tubular core and the plate core has a columnar core having a diameter smaller than the diameter of the other coil. Standing up, and in a state where the primary side portion and the secondary side portion are combined so that the opening of the cylindrical core and the standing coil of the plate-shaped core face each other, a closed magnetic circuit is formed and both coils are formed. A contactless power transmission device characterized by being arranged on concentric axes Place 2. The coil is wound around the core, and the wound coil is connected in series or in parallel with the coil on the side where the core is provided. Non-contact power transmission device.