JP2003059736A - Rotary transformer and non-contact intercircuit power transfer system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a rotary transformer which is small in total shape and does not require severeness in work accuracy and in assembling accuracy by simplifying core shape. SOLUTION: This rotary transformer is constituted by a pot-shaped core 102A formed of an annular magnetic-material element and having a roughly U-shaped cross section in axial direction, a disk-shaped core 104A formed of an annular magnetic-material element and having a radial-direction width which is the same as that of the pot-shaped core 102A, a primary coil 114 annularly arranged on an inner circumferential face of the feet 102a, 102b of the pot- shaped core 102A, and a secondary coil 116 annularly arranged on a position of the disk-shaped core 104A facing the primary coil 114 and keeping a specified distance from the primary coil 114. The secondary coil 116 is placed between the feet 102a, 102b of the pot-shaped core 102A, while the disk-shaped core 104A and the pot-shaped core 102A are arranged so as to be able to mutually rotate against each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact circuit-to-circuit transmission system for transmitting electric power or an electric signal in a non-contact manner between electric circuits arranged on two members that rotate relative to each other.

[0002]

2. Description of the Related Art Conventionally, as a means for transmitting electric power or electric signals between circuits by such a system, there is a rotary transformer as described in, for example, Japanese Patent Laid-Open No. 8-51041. This rotary transformer 1
00 is a primary stator 102 made of an annular ferromagnetic material whose axial cross section is formed into a substantially U-shape as shown in FIG.
And a leg portion 10 of the primary stator 102, which is also made of an annular ferromagnetic material whose axial section is U-shaped.
Secondary rotor 104 in which 8 and its legs 106 are combined
And the axis of the winding matches the axis of the primary stator 102,
The primary coil 114 received in one of the stator U-shaped leg portions 112 and one of the leg portions 106 of the U-shaped rotor whose winding axis line coincides with the axis line of the secondary rotor 104. Accepted by the primary coil 11
4 and the secondary coil 11 arranged at the same axial position.
6 and 6.

The U-shaped radially inner and outer legs 108-106 and 110-112 of the primary stator 102 and the secondary rotor 104 form magnetic fluxes between the primary stator 102 and the secondary rotor 104, respectively. For radially inner and outer air gaps G
1, G2 are formed, and the primary stator 102 and the secondary rotor 104 are arranged so as to be rotatable relative to each other.

In the rotary transformer 100 having such a structure, the primary stator 102 is attached to a fixed column of a vehicle (not shown), and the secondary rotor 104 is attached to a steering shaft (not shown) inserted through the fixed column. Then, the primary stator 102 causes the secondary rotor 10
By receiving the AC voltage electromagnetically induced in 4 as the power supply voltage by the electronic circuit mounted on the steering wheel attached to the steering shaft, electric power is supplied from the fixed column to the electronic circuit rotating with the rotation of the steering wheel in a non-contact manner. It is possible to activate an air bag that is transmitted by electric power and is attached to the steering wheel, for example.

[0005]

As described above, in the conventional rotary type transformer, the primary stator and the secondary rotor, in which the primary coil and the secondary coil are arranged, each have an individual cross section U.
It is arranged in a V-shaped core, and these cores are alternately meshed so that the primary coil and the secondary coil face each other. Accuracy of the gap length between the cores facing each other is required, and in order to meet this requirement, the processing accuracy and the assembly accuracy of the core become strict and the manufacturing cost increases.

The present invention has been made in order to solve the above problems, and provides a rotary transformer and a rotary transformer which have a simple core shape and are miniaturized, and do not require strict machining accuracy and assembly accuracy. The purpose is to obtain the non-contact inter-circuit transmission method used.

[0007]

As shown in FIG. 1, a rotary transformer 100A according to the present invention includes a pot type core 102A made of an annular magnetic material having an axially U-shaped cross section, and a pot type core 102A. A disk-shaped core 104A made of an annular magnetic material whose radial width is the radial width of the pot core 102A, and a primary coil annularly arranged on one inner peripheral surface of the leg portions 102a and 102b of the pot core 102A. 114 and a secondary coil 116 disposed in the disk-shaped core 104A in an annular shape at a position facing the primary coil 114 with a predetermined gap therebetween.
16 to the leg portions 102a of the pot type core 102A, 10
The disc type core 104A and the pot type core 102A are arranged so as to be mutually rotatable so as to face each other between 2b. According to the present invention, the pot type core 102 having a U-shaped cross section in which the primary coil 114 is annularly arranged on the inner peripheral surface.
The secondary coil 1 is formed in an annular shape between the legs 102a and 102b of A.
16 is arranged coaxially with the disk-shaped core 104A, and the primary coil 114 and the secondary coil 116 are arranged so as to face each other with a predetermined gap, so that the size of the entire plane is almost the same as that of the disk-shaped core 104A. Equivalent pot type core 102
A rotary transformer 10 that fits within the axial thickness of A
0A can be configured.

Rotary transformer 1 according to the present invention
In the non-contact inter-circuit power transmission method using 00A, a pot type core 102A made of an annular magnetic material having an axially U-shaped cross section, and the pot type core 102
A disk-shaped core 104A and a pot-shaped core 102A made of an annular magnetic material having a radial width of A as a radial width.
Primary coil 114 annularly arranged on one inner peripheral surface of each leg 102a, 102b, and secondary coil 116 annularly arranged at a position facing the primary coil 114 with a predetermined gap in the disk-shaped core 104A. And the secondary coil 116 is connected to the leg portion 102a of the pot type core 102A,
102b, the disk-shaped core 104A and the pot-shaped core 102A are rotatably arranged with respect to each other to form a rotary transformer 100A, and the pot-shaped core 102A is connected to a primary coil in a power supply unit as shown in FIG. 11
The secondary side fixed to the primary side control circuit CTR1 for connecting the ends of the No. 4 and the disk-shaped core 104A is fixed to the shaft inserted into the hollow part, and the end of the secondary coil 116 is fixed to the shaft. It is connected to the power supply unit of the control circuit CTR2, and non-contact electric power is transmitted between the control circuits CTR1 and CTR2 via the rotary transformer 100A. According to the present invention, the control circuits CTR1 and CT arranged in the fixed system and the rotary system respectively via the rotary transformer 100A according to the present invention.
Electric power or electric signals are transmitted between R2 without contact.

In the non-contact circuit-to-circuit transmission system using the rotary transformer according to the present invention, the primary side control circuit CTR1 modulates the AC signal applied to the primary coil 114 with the control signal to electromagnetically control the secondary coil 116. It is induced and transmitted to the secondary side control circuit CTR2. According to the present invention, not only the AC power is transmitted using the rotary transformer 100A, but also the modulated wave obtained by modulating the AC signal of a predetermined frequency with the control signal generated in the primary side control circuit CTR1 Electromagnetic induction from the coil 114 to the secondary coil 116 is sent to the secondary side control circuit CTR2, where the modulated wave is demodulated and the original control signal is extracted and provided for control operation on the rotary system side.

The rotary transformer 1 according to the present invention
In the non-contact electric circuit transmission method using 00A, at least one of the primary side control circuit CTR1 and the secondary side control circuit CTR2 starts a signal generation circuit with a voltage generated by electromagnetic induction by an external signal. Then, an AC signal is output and this AC signal is output to the rotary transformer 10.
Electric power is transmitted to the other control circuit by 0A. According to the present invention, the primary side control circuit CTR which is not supplied with power from the outside
1 or a high-frequency signal is sent to the secondary side control circuit CTR2 to start the signal generation circuit with a voltage generated by electromagnetic induction,
The alternating current signal output from this signal generating circuit is transmitted to the other control circuit in a contactless manner by the rotary transformer 100A.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a cross-sectional view in the axial direction of a rotary transformer used in the non-contact inter-circuit power transmission system according to the present embodiment. The rotary transformer 100A according to the present embodiment has a substantially U-shaped axial cross-sectional shape, and the U-shaped radially outer leg portion 102a and the radial direction having the same axial length as the leg portion 102a. An annular ferromagnetic pot-shaped core 102A composed of the inner leg portion 102b is provided as a stator. The primary coil 114 is wound around the inner peripheral surface of the leg portion 102b of the pot type core 102A by a coil bobbin 114a.

Also, the rotary transformer 100A
Is a ferromagnetic disk-shaped core 104A is a pot-shaped core 10
The rotor is arranged coaxially with 2A. A coil bobbin 116a is coaxially formed on the back surface of the disk-shaped core 104A.
Is formed, and the secondary coil 116 is wound around the coil bobbin 116a in the circumferential direction. Disc type core 104A
Is wound with the secondary coil 116 and the coil bobbin 116a
Is faced between the leg portions 102a and 102b of the pot type core 102A and is coaxially combined with the pot type core 102A so as to face the primary coil 114 with a predetermined gap.

Each of the cores 104A and 102A is made by mixing a predetermined amount of soft magnetic ferrite powder such as Ni-Zn ferrite or Mn-Zn ferrite into a synthetic resin such as nylon or polyphenylene filled (pps). It is a ring shaped. Incidentally, each core 104A,
102A is a soft magnetic ferrite sintered body molded in a ring shape (for example, Ni-Zn ferrite or Mn-Zn).
It is also possible to use a material obtained by mixing a system ferrite or the like with a binder agent and sintering the mixture. Each core is not limited to these materials.

In the rotary transformer 100A having such a structure, the pot core 102A is attached to a steering column (fixed system) provided on a steering shaft (not shown). The steering column is provided with a primary side control circuit for supplying electric power to the primary coil 114 or inputting / outputting an electric signal. The primary side control circuit supplies power or inputs / outputs a signal to / from the primary coil 114.

The disk-shaped core 104A is attached to the steering shaft (rotating system) via a coupling (not shown). AC power electromagnetically induced from the primary coil 114 to the secondary coil 116 is supplied to the secondary side control circuit attached to the steering wheel connected to the steering shaft from the secondary coil 116 provided on the disk-shaped core 104A. To be done. Alternatively, the secondary side control circuit inputs / outputs signals to / from the primary coil 114 through the secondary coil 116.

FIG. 2 is a diagram for explaining a non-contact inter-circuit power transmission system according to the present embodiment. In the figure, CT
R1 is a primary side control for inputting a sensor signal from, for example, an impact sensor provided in the engine room in front of the vehicle, and outputting a start signal and an AC voltage to an airbag inflator provided in the steering wheel based on the sensor signal. circuit,
100A is a rotary transformer that electromagnetically induces the AC voltage output from the primary side control circuit CTR1 by boosting the AC voltage from the primary coil 114 to the secondary coil. CTR2 is an airbag based on the AC voltage induced in the secondary coil 116. It is a secondary side control circuit which produces | generates the starting signal of an expander.

As shown in FIG. 3, the primary side control circuit CTR1 is connected by wirings R and S to a primary coil 114 fixedly provided on a steering column via a pot type core 102A (see FIG. 1). . Further, the secondary side control circuit CTR2 is connected to the steering wheel SW by an electronic circuit EC.
Is provided as. The electronic circuit EC has a primary coil 1
Secondary coil 11 that rotates around 14 via a disk-shaped core 104A attached to the steering shaft SS
Wirings U and V are connected to 6.

In such a structure, when the impact sensor (airbag sensor) detects a collision of the vehicle with another vehicle,
The primary side control circuit CTR1 generates an AC voltage based on the input sensor signal to generate the rotary transformer 100.
It is applied to the primary coil 114 of A. This AC voltage is boosted to a value determined by the winding ratio between the primary coil 114 and the secondary coil 116, induced in the secondary coil 116 by electromagnetic induction, and sent to the secondary side control circuit CTR2. Secondary side control circuit C
TR2 activates the airbag inflator by the induced AC voltage to instantly inflate the airbag.

In the above description, the rotary transformer 100A transmitted electric power from the primary coil 114 to the secondary coil 116. However, as shown in FIG. 4A, a predetermined frequency applied to the primary coil 114 has a predetermined frequency. An AC signal (carrier wave) is modulated with a sensor signal (modulation signal) by a modulation circuit as the primary side control circuit CTR1 and electromagnetically induced as a modulated wave in the secondary coil 116, and then the secondary side control circuit is provided on the steering wheel side. The sensor signal may be extracted by demodulation with the demodulation circuit (FIG. 4B) as the CTR2.

This sensor signal is applied to each filter (BPF) to determine the frequency, read the content of the sensor signal, and turn on the lamps PL1 to PL4 corresponding to the sensor signal to notify the abnormality or activate the oscillation circuit. It may be provided to an in-vehicle wireless LAN.

In the above description, the rotary transformer 10 is used.
Although the signal transmitted at 0 A is an analog signal,
As shown in (a), the primary side control circuit C as a modulation circuit
The data 01010 input to TR1 is converted into a baseband signal which is an ON / OFF pulse by a signal conversion circuit, and then the baseband signal is sent to a mixer, where the carrier wave input from the oscillator is modulated to modulate the modulated wave. As the primary coil 114 of the rotary transformer 100A
May be sent to.

The modulated wave sent to the primary coil 114 is electromagnetically induced by the secondary coil 116 and sent to the secondary side control circuit CTR2 as a demodulator, where the band pass (BP) is applied.
F) After being filtered, frequency components other than the carrier frequency are removed, and then mixed with the carrier in the mixer and demodulated. The demodulated signal is a low-pass filter (L
PF) to remove a carrier frequency component to generate a baseband signal, which is input to the determination circuit. The determination circuit determines [1] or [0] from the baseband signal and outputs the original data. Further, the determination circuit inputs the output data to the oscillator as a carrier wave reproduction synchronizing signal, and causes the mixer to input the carrier wave. The output original data may be provided to the in-vehicle wireless LAN by turning on the lamps PL1 to PL4 corresponding to the data to notify the abnormality, or by starting the oscillation circuit.

As described above, by using digital radio for data communication, even if waveform distortion occurs during data transmission by the rotary transformer 100A, the received data is subjected to waveform shaping to determine [1], [0]. As a result, data communication can be performed while maintaining a certain level of quality.

In this embodiment, the electric signal is transmitted from the primary side control circuit CTR1 to the secondary side control circuit CTR2 through the rotary transformer 100A. However, the signal in the secondary side control circuit CTR2 provided in the steering wheel SW is transmitted. A signal may be transmitted from the transmission circuit through the rotary transformer 100A to the primary side control circuit in a non-contact manner.

As an example of this signal transmission method, the secondary side control circuit CTR2 mounted on the steering wheel SW is provided.
When a power supply voltage is obtained by electromagnetic induction by a radio signal input from the outside, the power supply voltage activates the control signal generator to input the control signal to the secondary coil 116. The secondary coil 116 sends a control signal to the primary-side control circuit CTR1 through the primary coil 114 in a non-contact manner by electromagnetic induction, so that the primary-side control circuit CTR1 operates a controlled object based on the control signal. In this case, the control signal may be an analog signal or a digital signal.

The secondary-side control circuit CTR2 obtains the power supply voltage based on the input radio signal, determines the signal content, generates a control signal according to the signal content, and sends the control signal to the primary-side control circuit CTR1. The side control circuit CTR1 may determine the content of the control signal and operate the controlled object based on the content. The digital wireless data communication system is not limited to this system, and other systems using FSK, PSK, QAM, etc. may be used.

[0027]

According to the present invention, the open portion of the pot type core having a U-shaped cross section in which the primary coil is annularly arranged on the inner peripheral surface is made coaxial with the disc type core in which the secondary coil is annularly arranged. By arranging the covering primary coil and the secondary coil so as to face each other with a predetermined gap, it is possible to configure a rotary transformer that fits within the thickness of the pot core whose overall shape is almost the same as the planar shape of the disk core, so the overall shape can be made smaller. At the same time, since the core shape is simple, strict machining accuracy and assembly accuracy are not required, and the price can be kept low.

According to the present invention, power or electricity is provided between the control circuits arranged in each of the fixed system including the pot type core and the rotating system including the disc type core through the miniaturized rotary type transformer according to the present invention. Since the signal is transmitted in a contactless manner, there is an effect that the interference between the rotary transformer and surrounding devices can be eliminated as much as possible and the contactless transmission can be performed between the control circuits.

According to the present invention, not only the AC power is transmitted using the rotary transformer, but also the modulated wave obtained by modulating the AC signal of a predetermined frequency with the control signal generated in the primary side control circuit. The secondary side control circuit performs electromagnetic induction from the primary coil to the secondary coil and sends it to the secondary side control circuit, where the modulated wave is demodulated and the original control signal is extracted and used for control operation on the rotary system side. Since various control signals can be received from the primary side control circuit through a single signal path, there is an effect that the circuit can be made multifunctional.

According to the present invention, a high frequency signal is sent to the primary side control circuit or the secondary side control circuit which is not supplied with power from the outside to activate the signal generation circuit by the voltage generated by electromagnetic induction, and the signal generation circuit is activated. By transmitting the AC signal output by the rotary transformer to the other control circuit in a non-contact manner, the control circuit can be connected between both control circuits without being restricted by the direction of signal transmission due to the inclusion of the power supply section. There is an effect that signals can be exchanged.

[Brief description of drawings]

FIG. 1 is an axial cross-sectional view of a rotary transformer used in a non-contact inter-circuit power transmission system according to the present invention.

FIG. 2 is a diagram illustrating an outline of a non-contact inter-circuit power transmission system according to the present embodiment.

FIG. 3 is a diagram when a non-contact inter-circuit power transmission system according to the present embodiment is used in a vehicle steering device.

FIG. 4 is a diagram showing a schematic configuration of a primary side control circuit and a secondary side control circuit in the case of transmitting and receiving an analog signal by a non-contact inter-circuit power transmission method.

FIG. 5 is a diagram showing a schematic configuration of a primary side control circuit and a secondary side control circuit in the case of transmitting and receiving a digital signal by a non-contact inter-circuit electric transmission system.

FIG. 6 is a cross-sectional view of a conventional rotary transformer in the axial direction.

[Explanation of symbols]

100A rotary transformer 102A pot type core 102a, b legs 104A disc type core 114 primary coil 116 secondary coil CTR1 Primary side control circuit CTR2 Secondary side control circuit

Claims (4)

[Claims] 1. A pot-shaped core made of an annular magnetic material having an axially U-shaped cross section, and an annular magnetic material having a radial width of the pot-shaped core. A disk-shaped core, a primary coil annularly arranged on one inner circumferential surface of the leg portion of the pot-shaped core, and the disk-shaped core,
The secondary coil is arranged annularly at a position facing the primary coil with a predetermined gap, the secondary coil is faced between the legs of the pot-shaped core, the disk-shaped core and the pot-shaped core to each other. A rotary transformer characterized by being arranged so as to be mutually rotatable. 2. A pot-shaped core made of an annular magnetic material having an axially U-shaped cross section, and an annular magnetic material having a radial width of the pot-shaped core. A disk-shaped core, a primary coil annularly arranged on one inner circumferential surface of the leg portion of the pot-shaped core, and the disk-shaped core,
The secondary coil is arranged annularly at a position facing the primary coil with a predetermined gap, the secondary coil is faced between the legs of the pot-shaped core, the disk-shaped core and the pot-shaped core to each other. The rotary type transformer is arranged so as to be rotatable relative to each other, and the pot type core is provided in a primary side control circuit for connecting an end of a primary coil to a power source section, and the disk type core is attached to a shaft to be inserted into the hollow portion. In addition to fixing, the end of the secondary coil is connected to the power supply unit of the secondary side control circuit fixed to the shaft, and electric power or electric signals are contactlessly transmitted between the control circuits via the rotary transformer. A non-contact inter-circuit electrical transmission method that uses a rotary transformer that is characterized by electrical transmission. 3. The primary side control circuit modulates an AC signal applied to the primary coil with a control signal, electromagnetically induces the secondary coil, and transmits the electromagnetic signal to the secondary side control circuit. A non-contact inter-circuit power transmission method using the rotary transformer described in 2. 4. A control circuit of at least one of a primary side control circuit and a secondary side control circuit activates a signal generating circuit with a voltage generated by electromagnetic induction by an external signal to generate an AC signal, and the AC signal is generated. The signal is transmitted to the other control circuit by a rotary transformer.
A non-contact inter-circuit power transmission method using the rotary transformer described in.