JP3084158B2 - Signal transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device provided with a rotary transformer for transmitting a signal between a fixed body and a rotating body.

[0002]

2. Description of the Related Art A rotating body is provided with, for example, a torque sensor, an amplifier for amplifying a signal detected by the torque sensor, a control circuit for switching the gain of the amplifier, and the like. Power is supplied from the body side to the circuit provided inside the rotating body, a control signal is sent from the fixed body side to the control circuit, and a signal representing, for example, torque detected on the rotating body side is taken out to the fixed body side. In some cases, it is necessary to exchange signals and the like between the fixed body side and the rotating body side. A rotary transformer is used as one of means for transmitting and receiving signals between the fixed body and the rotating body. A rotary transformer is a type of transformer in which one of a primary winding and a secondary winding is provided on a fixed body side as a stator, and the other is provided on a rotating body side as a rotor.

[0003]

As described above, a rotary transformer is used as one of the means for transmitting and receiving signals between the fixed body and the rotating body. For example, in the case of the above-described configuration, the rotary transformer is used. A rotary transformer for transmitting power to be supplied to the circuit, a rotary transformer for sending a control signal to a circuit in the rotating body, and a rotary transformer for extracting a signal representing torque detected in the rotating body to the outside. This necessitates a problem that the number of rotary transformers increases and the size of the entire apparatus increases.

[0004] In view of the above circumstances, an object of the present invention is to provide a signal transmission device capable of reducing the number of rotary transformers.

[0005]

According to the present invention, there is provided a signal transmission apparatus comprising: (1) a fixed body; (2) a rotating body rotatable with respect to the fixed body; and (3) a stator mounted on the fixed body. A rotary transformer comprising a rotor attached to a rotating body; (4) an oscillation circuit provided on the fixed body side for outputting a power signal of a predetermined frequency, a control circuit for outputting a predetermined control signal, and a control circuit for outputting a predetermined control signal. A modulation circuit that obtains a modulated power signal by modulating the power signal and outputs the modulated power signal; and a power amplifier that amplifies the power of the modulated power signal and applies it to a stator. A power supply circuit for obtaining a predetermined constant voltage power from the modulated power supply signal transmitted to the rotor, a signal extraction circuit for extracting the control signal from the modulated power supply signal transmitted to the rotor, and a signal extraction circuit It is characterized in that it comprises a controlled circuit in controlled by the extracted control signal.

Here, the signal transmission device of the present invention may be configured to include a control circuit for outputting a pulse train signal as the control signal, and a modulation circuit for AM-modulating a power supply signal based on the pulse train signal. Good.

[0007]

According to the signal transmission device of the present invention, a power supply signal of a predetermined frequency is generated by an oscillation circuit on the fixed body side, and the power supply signal is modulated by a control signal output from the control circuit, amplified in power, and sent to the stator of the rotary transformer. On the rotating body side, the control signal is extracted from the modulated power supply signal output from the rotor of the rotary transformer to control the controlled circuit, and the modulated power supply signal is converted into a constant voltage to be the driving power of the circuit on the rotating body side. Which gives 1
Both power and signals transmitted from the fixed body side to the rotating body side are transmitted by one rotary transformer. Therefore, the number of rotary transformers can be reduced and the entire device can be downsized.

[0008]

Embodiments of the present invention will be described below. FIG. 1 is a circuit block diagram of a rotary torque sensor that incorporates an example of the signal transmission device of the present invention and detects a torque acting on a rotary rod. FIG. 2 is a signal waveform diagram of each part in FIG. Rotary torque sensor 1 whose circuit diagram is shown in FIG.
The rotating body 00 is formed in a substantially columnar shape, is mounted in the middle of the rotating rod as a part of the rotating rod, and detects a torque acting on the rotating rod.

The rotary torque sensor 100 includes a first rotary transformer 110 and a second rotary transformer 1.
20 are provided, and the respective stators 112, 12 of the first and second rotary transformers 110, 120 are provided.
2 is fixed to a fixed body, and each of the rotors 114 and 124 is fixed to a rotating body. Also, the rotational torque sensor 100
Is provided with a piezoelectric sensor 130 for detecting a torque acting on the rotating body. The piezoelectric sensor 130 generates an amount of electric charge according to a change in torque acting on the rotating body. This piezoelectric sensor 130
Are generated at the input side of the charge amplifier 140, the amount of the charge is converted into a voltage, and the voltage is output from the charge amplifier 140. This charge amplifier 140
Is completely discharged by the reset signal from the decoder and returns to the initial state, the gain is switched by the gain switching signal, and the charge accumulated by the time constant switching signal is gradually discharged in a controlled state. The time constant of the discharge at the time is switched. Output from the charge amplifier 140,
The voltage signal carrying the torque is converted by a V / F conversion circuit 160 into an FM signal whose frequency is ± △ f ₁ modulated with respect to the center frequency f ₀ according to the input voltage, and the rotor signal of the second rotary transformer 120 124. The FM signal input to the rotor 124 is transmitted to the stator 122, output from the stator 122, and input to the F / V conversion circuit 210. The F / V conversion circuit 210 converts the input FM signal into a voltage signal corresponding to the frequency. This voltage signal is output to the outside via output amplifier 220 as a signal representing the torque of the rotating body.

Further, an oscillation circuit 230 oscillating at a frequency f ₂ is provided on the fixed body side, and a power signal (FIG. 2A) having a frequency f ₂ is output from the oscillation circuit 230 to output an AM signal.
Input to modulation circuit 240. On the fixed body side, a reset switch for resetting the charge amplifier 140, a rotary switch for changing the gain of the charge amplifier 140, a charge switch 140
A rotary switch (not shown) for switching a time constant for switching the time constant is provided, and signals from these switches are input to the pulse train conversion circuit 250. FIG. 2B shows a reset signal input from a reset switch as an example. In the pulse train conversion circuit 250, the signals input from the switches are combined with each other in a time-series logic combination so that, for example, the reset signal (FIG. 2B) is converted into the pulse train signal of FIG. It is converted into a pulse train signal composed of different pulse trains.

[0011] The pulse train signal output from the pulse train conversion circuit 250 is also input to the AM modulation circuit 240. A
The M modulation circuit 240 generates a modulated power signal (FIG. 2 (d)) by amplitude-modulating the power signal input from the oscillation circuit 230 based on the pulse train signal input from the pulse train conversion circuit 250. This modulated power signal is power-amplified by the power amplifier 260 and input to the stator 112 of the first rotary transformer 110. The modulated power signal input to the stator 112 is
4 is transmitted. The power-amplified modulated power signal (FIG. 2E) output from the rotor 114 is input to the constant voltage power circuit 170. The constant voltage power supply circuit 170 rectifies the input modulated voltage signal to convert it to a predetermined constant voltage, and supplies the constant voltage to each circuit as electric power for operating each circuit provided in the rotating body. Further, the modulated power signal output from the rotor 114 is input to the AM demodulation circuit 180,
A pulse train signal (FIG. 2F) is extracted from the modulated power signal. The extracted pulse train signal is input to the decoder 150. The decoder 150 reads the input pulse train signal, and sends a predetermined control signal corresponding to the logical arrangement of the pulse train signal to the charge amplifier 140, for example, as shown in FIG.
The reset signal shown in (g) is output. As described above, charge amplifier 140 receives the control signal output from decoder circuit 150, and performs operations corresponding to the control signal, that is, each operation of reset, gain switching, and time constant switching.

As described above, in the above embodiment, the power supply signal is amplitude-modulated by the pulse train signal and sent to the rotator side, and the rotator side is separated into the constant voltage power and the pulse train signal. The signal is sent to the rotating body via one rotary transformer 110, so that the number of rotary transformers can be reduced and the size and cost of the apparatus can be reduced.

FIG. 3 is a signal waveform diagram showing another example of the pulse train signal. 3, signal waveforms corresponding to the respective signal waveforms in the signal waveform diagram shown in FIG. 2 are denoted by the same reference numerals as those shown in FIG. 2, and differences will be described. In the signal waveform diagram shown in FIG. 2, it has been described that the signal input from each switch is converted into pulse sequence signals having different time-series logics in pulse train conversion circuit 250, but in the example shown in FIG. For example, as shown in FIG. 3, a reset signal (b) and a gain switching signal (b) ′ for instructing to switch the charge amplifier 140 to a predetermined gain from each switch are different from each other as shown in FIG. The signal is converted into a pulse train signal having a repetition frequency, and the decoder 150 detects the repetition frequency and converts it into control signals (g) and (g) ′. As described above, the pulse train signal only has to follow a predetermined rule, and is not limited to a specific rule. FIG.
In the example shown in FIG.
The power supply signal output from 30 is converted to a pulse train conversion circuit 250
Is configured to amplify and modulate based on the pulse train signal output from the A / D converter. However, an FM modulation circuit is provided in place of the AM modulation circuit 240 and an FM demodulation circuit is provided in place of the AM demodulation circuit 180 to perform frequency modulation and demodulation. The present invention is not limited to a specific modulation method for modulating a power signal. Further, the present invention is not limited to application to a torque sensor. Next, another application example will be described.

FIG. 4 is a schematic diagram showing an example in which the signal transmission device of the present invention is applied to temperature measurement of a rotating body. Fixed body 30
0, a circular long hole 310 is formed.
0, a rotating body 400 is provided. Rotating body 40
The inside of 0 is provided with sensors 411_1, 411_2,..., 411_n for measuring the temperature of each part of the rotating body 400 (here, drawn for convenience of space), and these sensors 411_1, 411_2 are provided. , ……,
411 — n is connected to the amplifier via the switching circuit, and the output of the amplifier is connected to the V / F conversion circuit.
This V / F conversion circuit converts the input voltage signal representing the temperature into a frequency modulation signal (FM signal). This V
The FM signal output from the / F conversion circuit is input to the rotor 504 of the rotary transformer 500,
2 and input to the F / V conversion circuit on the fixed body side. In this F / V conversion circuit, the input FM modulation signal is converted into a voltage signal corresponding to the frequency, and this voltage signal is output to the outside via an output amplifier. Here, as described above, a large number of sensors 411_1, 411_2,.
, 411_n are connected to the amplifier via a switching circuit, so that only one circuit is required after the amplifier. However, by controlling this switching circuit, a large number of sensors 411_1, 411_2,... , 411 — n must be externally input with a control signal for controlling which one is connected to the amplifier. Therefore, here, a switching signal set by a switch or the like (not shown) is input to the control circuit, converted into a control signal by the control circuit, and the power supply signal is modulated by the power supply circuit based on the control signal. Input to stator 502. The modulated power signal is transmitted to the rotor 504 and demodulated on the rotating body to control the switching circuit. The power signal is also rectified and converted to a constant voltage, and each of the rotating body side such as an amplifier and a V / F conversion circuit is controlled. Supplied to the circuit.

As described above, the signal switching circuit of the present invention can be widely applied to a case where it is necessary to transmit both power and a control signal from the fixed body to the rotating body. In the embodiment described with reference to FIG. 4, the power and control signals transmitted from the fixed body to the rotating body as well as the temperature detection signal transmitted from the rotating body to the fixed body are transmitted via the same rotary transformer 500. However, as long as the power signal is modulated by a control signal and transmitted from the fixed body side to the rotating body side via the rotary transformer, the present invention is included in the present invention, and this same rotary transformer is used for other circuits, for example, As shown in FIG. 4, a circuit for transmitting the detection signal from the rotating body side to the fixed body side may be shared.

[0016]

As described above, the signal transmission apparatus of the present invention modulates a power signal of a predetermined frequency with a control signal,
Since both the power and the control signal are transmitted to the rotating body via the rotary transformer, the number of rotary transformers can be reduced, and the size and cost of the entire apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 illustrates an example of a signal transmission device according to the present invention.
FIG. 3 is a circuit block diagram of a rotation torque sensor that detects a torque acting on a rotation rod.

FIG. 2 is a signal waveform diagram of each part in FIG.

FIG. 3 is a signal waveform diagram showing another example of a pulse train signal.

FIG. 4 is a schematic diagram showing an example in which the signal transmission device of the present invention is applied to temperature measurement of a rotating body.

[Explanation of symbols]

Reference Signs List 100 rotation torque sensor 110, 120 rotary transformer 130 piezoelectric sensor 140 charge amplifier 150 decoder 160 V / F conversion circuit 170 constant voltage power supply circuit 180 AM demodulation circuit 210 F / V conversion circuit 220 output amplifier 230 oscillation circuit 240 AM modulation circuit 250 pulse train Conversion circuit 260 Power amplifier 300 Fixed body 400 Rotating body 411_1, 411_2, ..., 411_n Temperature sensor 500 Rotary transformer 502 Stator 504 Rotor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-247778 (JP, A) JP-A-58-140441 (JP, U) JP-A-4-15797 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) G08C 13/00-25/04

Claims (2)

(57) [Claims] 1. A fixed body, a rotating body rotatable with respect to the fixed body, a rotary transformer including a stator attached to the fixed body and a rotor attached to the rotating body, provided on the fixed body side. An oscillation circuit that outputs a power signal having a predetermined frequency, a control circuit that outputs a predetermined control signal, and a modulated power signal obtained by modulating the power signal based on the control signal to obtain the modulated power signal. A modulating circuit for outputting, a power amplifier for amplifying the power of the modulated power signal and applying the power to the stator; and obtaining a predetermined constant voltage power from the modulated power signal attached to the rotating body and transmitted to the rotor. Power circuit,
A signal extraction circuit for extracting the control signal from the modulated power supply signal transmitted to the rotor, and a controlled circuit controlled by the control signal extracted by the signal extraction circuit. Transmission equipment. 2. The control circuit according to claim 1, wherein the control circuit outputs a pulse train signal as the control signal, and the modulation circuit performs AM modulation on the power supply signal based on the pulse train signal. Item 2. The signal transmission device according to Item 1.