JP2007157985A - Non-contact power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact power supply system using a coreless printed coil. <P>SOLUTION: Printed coils are employed as coil means for electromagnetic induction. The printed coils 60 and 90 have a coil pattern 96 on both front and rear faces of an insulation substrate 690. Their coil patterns 96 on the front and rear are electrically connected in parallel. Thus, predetermined power required as a power source is obtained. When the printed coils 60 and 90 are assembled, a plurality of posts 50 may be used. Part of the posts 50 can be used to electrically connect both coil patterns 96 on the front and rear. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for supplying power in a non-contact manner from a fixed side having a power source to a rotating side having no power source, and particularly relates to a technology for supplying power by electromagnetic induction.

  When measuring physical properties on the rotating side such as a rotating shaft (for example, torque, load, temperature, displacement, pressure, vibration, etc.), the physical properties to be measured are detected as electrical signals on the rotating side and are suitable for transmission. Detection / conversion means for performing conversion processing on the received signal is arranged. A power source is required to drive the rotation side detection / conversion means. From the viewpoint of miniaturization, the rotating side usually does not have a power source, and the rotating side detection / conversion means is supplied with electric power by using a fixed side power source.

  As a method for supplying power from the fixed side to the rotating side, a non-contact type using a rotary transformer is known in addition to a mechanical contact type using a slip ring and a brush. When both are compared, the latter non-contact type is superior in terms of reliability and durability (see Patent Documents 1 and 2).

The non-contact type has a transmission coil means on the fixed side and a reception coil means on the rotation side, supplies power from the power source to the transmission coil means on the fixed side, and generates electromotive force on the reception coil means on the rotation side by electromagnetic induction. To drive rotation-side detection / conversion means (in addition to detection / conversion means, for example, transmission means for receiving a conversion signal from the detection / conversion means and transmitting it in a non-contact manner) Provide.
JP 2001-221698 A Japanese Patent No. 34488738

  A non-contact type rotary transformer has a configuration in which a winding coil is supported on a circular ferrite core, for example. There is a core with such a winding coil on the transmission side and the reception side, an AC voltage is applied to the transmission side, an electromotive force is generated on the reception side by electromagnetic induction, and it is stabilized to Used as a drive power supply. However, such a rotary transformer has several drawbacks. First, it is unsuitable for various kinds of small-volume production. Since the winding coil winds an electric wire (coil) around the bobbin, the bobbin must be processed according to the type. In addition, since the core is powder-molded using a mold, it is premised on a certain amount of mass production, and in the production of a small amount of various kinds, the processing cost becomes high and it is not profitable. Second, since there is a core, there is a limit in terms of miniaturization.

  In view of such difficulties, the inventor has focused on a printed coil in which the coil is patterned. This is because by making the coreless, and by eliminating the need for the bobbin, it is possible to eliminate the disadvantages of conventional winding coils with a core. Moreover, since the coreless printed coil does not use the core and the winding coil, the space occupied in the apparatus can be reduced, the apparatus can be reduced in size and weight, and the cost is advantageous. Furthermore, the printed coil is suitable for small-scale production because it has a coil pattern on an insulating substrate.

  However, the coreless printed coil has a lower inductance of the coil component along with the coreless, and does not function as a substitute for a normal rotary transformer. In order to solve this problem, it was considered to form coil patterns on both the front and back surfaces of the insulating substrate. And, I experimented and examined various kinds of printed coils with coil patterns on both sides. As a result, in order to increase the inductance, a method of connecting both the front and back coil patterns in series is usually adopted. However, in this method, a power large enough to drive the rotating circuit is obtained. Turned out to be difficult. In order to increase the power in series connection, the thickness and / or width of the coil pattern must be increased. However, the pattern thickness cannot be increased due to standard restrictions, and the pattern width must be increased. If this is the case, the overall size reduction cannot be achieved.

  Therefore, an object of the present invention is to provide a useful non-contact type power supply system using a coreless printed coil. Other objects of the present invention will become clear from the following description.

  For electromagnetic induction, it is necessary to provide transmission coil means on the fixed side with power supply and reception coil means on the reception side without power supply, and arrange these coil means so as to face each other. is there. In the present invention, both the coil means are constituted by a printed coil having a coil pattern on an insulating substrate.

  The coil pattern of the printed coil is a very thin spiral conductor pattern having a thickness of 35 μm, for example. In order to reduce the size, it is necessary to reduce the pattern width and secure the number of coil turns that produces an effective electromagnetic induction effect. However, if the pattern width of the coil pattern is so thin, the cross-sectional area of the conductor pattern becomes small, and a predetermined current cannot flow. Therefore, in this invention, a coil pattern is formed on both front and back surfaces of the insulating substrate, and the coil patterns on both front and back surfaces are connected in parallel. With such a configuration in which the coil patterns on both the front and back surfaces are connected in parallel, a predetermined power can be obtained while reducing the size of the printed coil.

  The electromotive force induced in the rotating side print coil as the receiving coil means is a minute power because it is a coreless print coil. In order to make the minute electric power more effective as a power source, it is preferable to increase the output. For this purpose, it is preferable to form a parallel resonance circuit in the rotation side printed coil. The parallel resonance circuit can increase the amplitude of the voltage induced in the rotation-side printed coil, and an output voltage that is, for example, about four times the supply voltage of the transmission-side printed coil can be obtained. This increased voltage can be used as a power supply on the rotating side after normal processing, that is, rectification, smoothing, and stabilization.

  The fixed side printed coil as the transmitting coil means and the rotating side printed coil as the receiving coil means are separated from each circuit so as not to adversely affect the rotating side and fixed side circuits due to electromagnetic induction. It is preferable to arrange (that is, with a predetermined gap). As the technique, a method of supporting a flat plate-shaped printed coil having a coil pattern on both front and back surfaces of an insulating substrate with a plurality of columns can be adopted. The pillars are distributed around a generally circular printed coil, e.g. 3-5 spaced apart. Preferably, the coil patterns on both the front and back sides are electrically connected using at least one of the support columns.

  Usually, what constitutes the rotating side is a shaft. Therefore, each printed coil can be shaped like a donut with a hole inside each of the front and back coil patterns, and the shaft can be inserted into the inner hole.

  The present invention can be widely applied to a case where power is supplied in a non-contact manner from a fixed side having a power source to a rotating side having no power source.In particular, an electrical signal measured on the rotating side is applied to the fixed side. The present invention can be suitably applied to cases involving transmission means. By applying the present invention to such a measurement technique, the system or apparatus can be reduced in size and weight, and can withstand high-speed rotation and perform stable data transmission for a long period of time.

  FIG. 1 is an overall configuration diagram of a rotational torque meter to which the present invention is applied, and FIG. 2 is a block diagram showing its circuit configuration. The rotational torque meter includes a shaft 10 that extends straight. The shaft 10 is a main body on the rotation side, and connects the drive shaft to one end portion 10D and connects the driven shaft to the other end portion 10F. There is a portion 10C in the middle of the shaft 10 that is likely to cause strain, and a strain gauge is attached thereto. That is, the portion 10C is a torque detector.

  The shaft 10 is rotatably supported by a pair of side plates 12 and 14 including bearings, and integrally supports the rotation module 20 at a central portion adjacent to the torque detection portion (portion 10C). The rotation module 20 is integrally provided with two modules separated in the axial direction on the inner periphery of the outer protective ring 210. One of the modules is a torque measurement / transmission unit module 30 as a detection / conversion unit that receives a detection signal from the torque detection unit and converts it into a conversion signal suitable for transmission. The other module is a power receiving module 40, which has a power receiving printed coil 60 supported by a support 50, as will be described in detail later.

  The pair of side plates 12 and 14 are components on the fixed side. The side plate 12 close to the torque detector integrally supports the torque signal receiver module 70 via the spacer 12S. Similarly, the other side plate 14 integrally supports the power transmission module 80 via the spacer 14S. A power supply print coil 90 is supported on one side of the power transmission module 80 by a support 50.

  FIG. 3 shows an equivalent circuit diagram of the power transmission / reception unit. Each circuit for power transmission / reception will be described with reference to FIG. 3 and FIG. 2 showing a block diagram. On the fixed side, for example, there is a power supply unit 100 that receives input from a DC 12 volt power supply. The power supply unit 100 applies a predetermined power supply voltage to each circuit on the fixed side. The modularized power supply transmission module 80 on the fixed side includes a pulse transmitter 810 connected to the power supply unit 100, and a switching element 820 that switches on / off a signal from the pulse transmitter 810, for power transmission. A pulsed voltage is applied to the print coil 90. Since the inductance on the printed coil 90 side is low, the switching frequency is set high (in the range of 450 kHz to 600 kHz).

  The fixed-side power transmission print coil 90 faces the rotation-side power reception print coil 60 and generates an electromotive force in the print coil 60 by electromagnetic induction. A rectifying / smoothing circuit 410 and a parallel resonance circuit 420 including an inductance L and a capacitor C are formed in a portion following the rotating-side printed coil 60, and the voltage induced in the printed coil 60 is rectified and smoothed and further increased. . Thereby, for example, a voltage increased by about 4 times can be obtained. The increased voltage is stabilized by the constant voltage circuit 430 and then used for driving the torque measurement / transmission unit module 30 on the rotation side. Here, it is preferable to use a capacitor C having excellent temperature characteristics and suitable for a high frequency circuit for the parallel resonance circuit 420. In that respect, sufficient performance can be exhibited in a wide temperature range of −10 ° C. to + 80 ° C. by using a capacitor having a withstand voltage of 100 volts or more with a polypropylene film.

  FIG. 4 is an equivalent circuit diagram of the measurement signal transmission / reception unit. A circuit for transmitting and receiving measurement signals will be described with reference to FIG. 4 and FIG. 2 showing a block diagram. The torque measurement / transmission unit module 30 on the rotation side receives a detection signal based on a change in electrical resistance from the torque detection unit 10C, amplifies the detection signal, and the amplified signal from the amplifier 310 is converted into a voltage-frequency (V-F). ) The converter 320 for conversion and the pulse transmission unit 330 for transmitting the conversion signal from the converter 320 as a pulsed optical signal are integrally provided. On the other hand, the fixed-side torque signal receiving unit module 70 facing the rotation-side torque measuring / transmitting unit module 30 includes a pulse receiving unit 710 including an infrared photodiode that receives an optical signal transmitted from the pulse transmitting unit 330. In addition, there are a converter 720 that performs frequency-voltage (F-V) conversion of the signal from the pulse receiving unit 710, an amplifier 730 that amplifies the converted signal by the converter 720, and the like.

Now, the rotation-side rotation module 20 and the fixed-side power transmission module 80 that are modularized have ring shapes in which both side surfaces are parallel to each other. For this reason, the power supply receiving print coil 60 and the power supply print coil 90 which are both flat can be supported so as to face each other by setting up the support column 50 on each one side surface thereof. Both the printed coils 60 and 90 have spiral coil patterns 96 on both the front and back surfaces of the insulating substrate 690 and have the same overall configuration. Each printed coil has the following specifications, for example.
Thickness of donut-shaped insulating substrate: 1.6 mm
Dimensions of the insulating substrate: outer diameter 80 mm x inner diameter 46 mm
Copper foil coil pattern thickness: 35μm
Coil pattern width: 0.25mm
Gap between patterns: 0.25mm
Number of vortices: 18 turns The printed coils 60 and 90 are arranged with a space that does not affect the effect of electromagnetic induction on adjacent modules. Increasing the frequency and increasing the number of spirals of the coil pattern can lower the frequency.

  FIG. 5 shows the front of the printed coil 60 (90). On a donut-shaped insulating substrate 690, four support columns 50 are arranged on the outer periphery of the coil pattern 96 at substantially equal intervals in the circumferential direction. These columns 50 are made of a conductive material, and the upper left part of the figure is used as a column and also used to electrically connect the front and back coil patterns. Therefore, it is easy to assemble the printed coil and no wiring is required.

1 is an overall configuration diagram of a rotational torque meter to which the present invention is applied. It is a block diagram which shows the circuit structure of the rotational torque meter of FIG. It is an equivalent circuit diagram of a power transmission / reception part. It is an equivalent circuit diagram of a measurement signal transmission / reception unit. It is a front view of a printed coil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shaft 20 Rotation module 30 Torque measurement / transmission part module 40 Power supply reception part module 50 Strut 60 Print coil for power reception 70 Torque signal reception module 80 Power transmission part module 90 Print coil for power supply 100 Power supply part (power supply)

Claims (8)

A non-contact type power supply system for performing non-contact power supply from a fixed side having a power source to a rotating side having no power source,
A detection / conversion means that is located on the rotation side, detects physical characteristics of the rotation side as an electrical signal, and converts the signal into a signal suitable for transmission;
Transmitting coil means that is located on the fixed side and receives a supply of electric power from the power source on the fixed side and through which a predetermined current flows,
A receiving coil means positioned on the rotating side, facing the fixed transmitting coil means and generating electromotive force by electromagnetic induction in combination with the transmitting coil means, and using the voltage based on the receiving coil means, A non-contact type power supply system characterized by the following points in the power supply to the rotating side.
(A) Both the transmitting coil means and the receiving coil means are composed of printed coils having a coil pattern on an insulating substrate. (B) Each of the printed coils has a coil pattern on the front and back of the insulating substrate ( C) Connect both the front and back coil patterns in parallel.   The power supply system according to claim 1, further comprising transmission means for transmitting a conversion signal from the detection / conversion means to the fixed side in a contactless manner.   The power supply system according to claim 1, wherein the detection / conversion means includes a converter that converts the detected electrical signal into a voltage-frequency.   2. The power supply system according to claim 1, wherein the fixed side and the rotating side printed coils are respectively supported by a plurality of support columns, and at least a part of the support columns is used for electrical conduction.   2. The power supply system according to claim 1, wherein each of the printed coils has a donut shape having a hole inside the coil pattern, and a shaft constituting the rotating side can be inserted into the hole.   The power supply system according to claim 1, wherein the physical property on the rotating side is at least one of torque, load, temperature, displacement, pressure, and vibration.   The transmission means includes a transmission means that is located on the rotation side and transmits a conversion signal from the detection / conversion means, and a reception means that is located on the fixed side and receives a transmission signal transmitted from the transmission means. The power supply system according to claim 2.   The power supply system according to claim 7, wherein the transmission means is based on an optical signal.

Images