JPH0897754A - Signal transmission device - Google Patents

Abstract

(57) [Summary] [Purpose] Communication between two devices that move relatively
Signal transmission that is small and has excellent noise immunity when performing signal transmission.
Provide a feeding device. [Structure] Relative while facing each other with a predetermined gap
Two transmitting and receiving elements 2a, 3a that are movable
In the signal transmission device 1a having the two transmission / reception elements
Components 2a and 3a are made of a conductive material and have the same center.
It has a ring shape with a shaft and is located on the outer peripheral side of the predetermined gap 4a.
Located on the inner circumference side of the outer ring portion 3a located and a predetermined gap
The inner ring portion 2a, and each of which faces each other.
Surface S_1a, S _2aIs a concavo-convex shape that increases the total area of the facing surface.
It is molded into a shape. Sawtooth shape, rectangular shape
Etc. apply. Both elements are capacitively coupled and
The frequency signal can be efficiently transmitted.

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,
More specifically, in order to exchange signals between the rotating unit and the fixed unit that controls the rotating unit, a portion in which the transmitting unit and the receiving unit rotate relative to each other is provided so as not to affect the mutual rotation. The present invention relates to a signal transmission device for transmitting a signal in a non-contact state.

As a method of using these signal transmission devices, for example, in a rotary type inspection machine installed in a factory, a sensor for inspecting a manufactured product is mounted and a control signal is transmitted between the sensor and a control unit. When transmitting and receiving, it can be considered to be used for an electrical joint between the rotating part and the fixed part.

[0003]

2. Description of the Related Art Generally, a wireless transmission system using a transmitting antenna and a receiving antenna is used for transmitting signals in a contactless manner when a signal transmitting unit and a signal receiving unit move independently of each other. To be In particular, when the transmitting antenna and the receiving antenna are in close contact with each other at short distances, antennas that are opposed to each other are provided to transmit and receive radio waves without using an antenna as is found in ordinary long-distance wireless communication.

FIG. 14 shows a conventional signal transmission device (transmission / reception element). As shown in FIG. 14, in a conventional signal transmission device, a loop antenna-shaped transmitting element 101 and a receiving element 102 are installed with a predetermined distance therebetween so that one of the two elements is fixed and the other is rotatably installed. . A signal is supplied to the transmitting element 101 at the feeding point T ₁ , and a signal is output to the receiving element 102 from the feeding point T ₂ .

FIG. 15 (A) shows the relationship between the relative angle of both elements and the obtained signal strength when the case where both elements are located at the angle where both feeding points face each other is 0 degree. As can be seen from FIG. 15 (A), both feeding points are 0
It has been found that the most efficient use of signals is achieved when located at °.

[0006]

However, in the above-mentioned conventional signal transmission device, a large element is required to obtain the required frequency characteristic as shown in FIG. 15 (B), and the signal transmission device is required. It was not possible to miniaturize itself. For example, a conventional signal transmission device as shown in FIG. 14 has an outer diameter of 20 cm or more, and the entire configuration including the shield cover is large.

Further, when a signal transmission device is used in an inspection machine or the like, it is required that the signal transmission device can withstand external noise from a peripheral motor or the like. However, the conventional signal transmission device has a high impedance in a high frequency signal and a large size. Combined with this, it is susceptible to noise, so noise countermeasures were required.

Therefore, an object of the present invention is to provide a signal transmission device which is small in size and excellent in noise resistance when performing signal transmission between relatively movable (rotating) devices.

[0009]

According to the first aspect of the present invention,
In a signal transmission device having two transmitting and receiving elements that are relatively movable while facing each other with a predetermined distance therebetween, the two transmitting and receiving elements are made of a conductive material,
The opposing surfaces of the transmitting / receiving element, which are opposed to each other, are formed in a concavo-convex shape that increases the total area of the opposing surfaces.

FIG. 1 shows a signal transmission device according to the second aspect of the present invention.
Shown in. As shown in FIGS. 1 (A) and 1 (B), the invention according to claim 2 is a signal transmission having two transmission / reception elements 2a and 3a that are relatively movable while facing each other with a predetermined space therebetween. In the device 1a, the two transmission / reception elements 2a and 3a are made of a conductive material, and each of the transmission / reception elements is a ring-shaped object that relatively rotates about the same rotation center, and is located on the outer peripheral side of the predetermined gap 4a. Has an outer ring portion 3a located on the inner circumference side and an inner ring portion 2a located on the inner circumference side of a predetermined gap, and the facing surfaces of the outer ring portion and the inner ring portion are S _1a and S _2a , respectively. , Is formed in a concavo-convex shape that enlarges the total area of the facing surface.

According to a third aspect of the invention, in the signal transmission apparatus according to the second aspect, (n + 1/4) with respect to λ of the signal wavelength at the center frequency of the transmission frequency band to be transmitted and received.
A coil including a conductive material whose winding length is adjusted to have a length corresponding to λ (n = 0, 1, 2, ...) Is provided. Note that the conductive material includes linear shapes, planar shapes, and the like.

According to a fourth aspect of the present invention, in the signal transmission device according to the second aspect, the outer ring portion and the inner ring portion are provided with a plurality of feeding points for electrically connecting to the element body, and respective feeding feeding points. A matching device is provided between the plurality of feeding points to distribute signals between the feeding points or mix signals from the feeding points to match impedances.

FIG. 1B is a sectional view of the signal transmission device according to the fifth aspect. As shown in FIG. 1 (B), in the invention according to claim 5, the concavo-convex shape of each of the facing surfaces S _1a and S _2a is formed in a sawtooth shape, and the convex portion of one facing surface and the other facing surface are formed. The recesses are close to each other with a predetermined gap 4a in such a positional relationship that they are engaged with each other.

FIG. 2B is a sectional view of the signal transmission device according to the sixth aspect. As shown in FIG. 2 (B), in the invention according to claim 6, the concavo-convex shape of each of the facing surfaces S _1b and S _2b is formed in a rectangular shape, and the convex portion of one facing surface and the other facing surface are formed. The recesses are close to each other with a predetermined gap 4b in such a positional relationship that they are engaged with each other.

[0015]

According to the invention described in claim 1, the two transmitting and receiving elements are formed by molding a conductive material. Both elements are
Since the respective facing surfaces facing each other have a concavo-convex shape so as to increase the total area thereof, the electrostatic capacitance between both elements becomes large, and the impedance between both elements significantly decreases.

According to the invention described in claim 2, FIG.
As shown in FIG. 2, the two transmitting / receiving elements 2a and 3a are made of a conductive material and are molded into a ring-shaped object that rotates around the same axis of rotation, so that fixing one of them allows the other to rotate. Becomes Each of the facing surfaces S ₁ and S ₂ facing each other serves as a radio wave emitting surface when a signal is supplied and serves as a radio wave receiving surface when a signal is received. Since the respective facing surfaces are formed in a concavo-convex shape that increases the total area, the electrostatic capacitance between both elements becomes large, and the impedance between both elements significantly decreases.

According to the third aspect of the present invention, one of the coils provided on each of the outer peripheral end surface of the outer ring portion and the inner peripheral end surface of the inner ring portion is made of a conductive material for the supplied signal. To the element of. Since both elements are made of a conductive material, the change in magnetic flux induced in one coil is transmitted to the other coil without being attenuated. The other coil induces a signal current as the transmitted magnetic flux density changes.

A coil is provided which includes a conductive material (having a shape such as a line or a band) having a wavelength (n + 1/4) wavelength (n = 0, 1, 2, ...) Which has the highest transmission efficiency as the winding length of the coil. Therefore, the change in the signal current is most efficiently converted into the change in the magnetic flux density.

According to the fourth aspect of the present invention, when a signal is supplied to either one of the transmitting and receiving elements divided into the outer ring portion and the inner ring portion, one balun performs impedance matching of the signal, and a plurality of feeding points are provided. This signal is supplied. One element radiates a signal from the opposite surface, and the opposite surface of the other element receives the transmitted signal. The other element supplies the signal transmitted from the plurality of feeding points to the matching device. The other matching unit performs impedance matching of the signals supplied from the plurality of feeding points, mixes the signals supplied from the plurality of feeding points, and outputs the mixed signals.

As shown in FIG. 1 (B), according to the invention of claim 5, wherein, facing surfaces S _1a, sawtooth formed into S _2a is occupying become large surface area of the facing surfaces S _1a and S _2a . Also,
Since the shapes of the facing surfaces S _1a and S _2a of both elements are such that they mesh with each other, the gap 4a becomes narrow. Therefore, the capacitance between the two elements 2a and 3a is increased, and the impedance between the two elements is reduced.

As shown in FIG. 2 (B), according to the sixth aspect of the present invention, the facing surface S _1b, like rectangular molded into S _2b is occupying become large surface area of the facing surfaces S _1b and S _2b . Further, since the facing surfaces S _1b and S _2b of both elements are shaped so as to mesh with each other, the gap 4b becomes narrow. Therefore, the capacitance between the two elements 2b and 3b increases, and the impedance between the two elements decreases.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a signal transmission device of the present invention will be described with reference to the drawings. (I) First Embodiment In a first embodiment of the present invention, a rotary inspection device, a signal transmission device according to claims 1, 2 and 3 and a sawtooth facing surface according to claim 5 are provided. This is an application of the signal transmission device. Of course, in addition to the saw-toothed facing surface described in claim 5, the rectangular facing surface described in claim 6 or the like can be applied.

Description of configuration i) Rotary inspection to which the signal transmission device of the present invention is applied
Device FIG. 7 shows an overall view of a rotary type inspection device to which the signal transmission device described above is applied. The rotary inspection apparatus 200 according to the present embodiment is used in a production line for manufacturing containers such as bottles in order to detect defects and foreign substances existing in a produced bottle (hereinafter referred to as “work bottle”). It is installed in the inspection process.

As shown in FIG. 7, in the rotary inspection device 200, the conveyor H conveys the manufactured work bottle B, and the star wheel 12 synchronizes the conveyance speed with the rotation speed of the inspection device. The base 14 is responsible for the main rotation of the inspection device by a built-in rotary motor or the like. The rotation inspection table 16 conveys the work bottles B conveyed by the star wheel 12 at an equal angular velocity in the arrow direction, and each of the work bottles B is rotated by a gear mechanism (not shown) connected to the cam follower 18. Also, the cam follower 18
Moves along the cam 19 fixed to the base 14 as the rotation inspection base 16 rotates. Work bottle B is cam 1
Cam follower 1 driven in the vertical direction by the action of 9
The shaft 17 integrated with the shaft 8 reciprocates.
The turntable 20 is attached with a set of a plurality of endoscopes 13 and a CCD camera 15, and is fixed to a rotation shaft 22 together with the rotation inspection table 16 and is entirely driven by a rotary motor or the like.

The camera selector 24 simultaneously selects and outputs a plurality of transmission channels (for example, 6 channels).
The selector 24 selects some cameras from the plurality of cameras 15, captures necessary images, performs A / D conversion,
It is a digital signal. Further, the selector 24 outputs the transmission signal of each transmission frequency. The mixer 26 frequency-mixes the digital signals of the plurality of transmission channels output by the selector 24. The antenna unit 28 is composed of a shield body and the signal transmission device body 1c of the present invention (see FIG. 3). The digital transmission signal mixed by the mixer 26 is transmitted through the antenna unit 28, converted into a normal NTSC signal, and transmitted to the inspection unit 32. The control unit 30 also sends a control signal via the antenna unit 28 to control the operation of the control motor and the like of each unit of the inspection device. The rotary resolver 34 and the fixed resolver 36 are devices that give angular position information such as a rotation axis by an electric signal. The rotary resolver 34 detects angular position information on the rotary block side. The fixed resolver 36 detects angular position information on the fixed side. Both resolvers detect the rotation angle by a gear (not shown) provided between the fixed block side and the rotary block side.

Ii) Main Body of Signal Transmission Device FIG. 3 shows a block diagram of the signal transmission device of the first embodiment stored in the antenna section 28 of FIG. 7A is a front view and a side view of the signal transmission device 1c of the present embodiment, and FIG. 8B is a cross-sectional structural view taken along the alternate long and short dash line in FIG.

As shown in FIG. 3A, the signal transmission device 1c of the embodiment is a signal transmission device main body 1a according to claim 5 of FIG. 1 in which a coil is provided, and serves as an antenna. An inner ring portion 2a whose part is made of iron (Fe) and an inner ring portion 2a can be relatively rotated with a predetermined gap 4a between them, and an outer ring portion 3a made of aluminum (Al). ,,. The inner ring portion 2a is manufactured to have an inner diameter DI of 12 cm, for example, and the outer ring portion 3 is formed to have an outer diameter DO of 14 cm, for example.

As shown in FIG. 3B, an inner peripheral coil 5 for controlling signal transmission of the inner ring portion 2a is provided on the inner peripheral surface of the inner ring portion 2a. An outer peripheral coil 6 that controls the signal transmission of the outer ring portion 3a is provided on the outer peripheral surface of the outer ring portion 3a. The conductive wire of each coil is covered with an insulating film such as enamel, and the conductive wire is fixed by an insulating material 7 such as resin in a state of being wound a predetermined number of times. The insulating material 7 is provided on either end face of each element so that the element body and the shield body are electrically insulated when the signal transmission device 1c is fixed to a predetermined shield body (see FIG. 9). It is provided only on the surface of. The conducting wire of the coil may have a strip shape or the like instead of the insulating coating conducting wire.

The difference in the conductive material used in the inner ring portion 2a and the outer ring portion 3a is due to the manufacturing requirement for forming a narrower gap. In other words, since iron and aluminum have different coefficients of thermal expansion, if both elements are combined with each other with a relatively wide gap 4a in a high heat state during manufacturing, both elements will shrink with a decrease in temperature, and finally a very narrow gap will result. Can be made. In this way, the gap 4a is, for example,
When the standard value is set to 1.3 [mm], it can be manufactured within an error range of ± 0.7 [mm].

As described above, as the conductive material, the signal transmission device of the present invention can be manufactured as long as it is a conductive material having a different coefficient of thermal expansion regardless of the combination of iron and aluminum. Further, when the manufacturing method utilizing the difference in the coefficient of thermal expansion is not used, the conductive material may be the same kind of material (for example, aluminum) as the material of both elements.

Further, the facing surfaces of the inner ring portion 2a and the outer ring portion 3a are formed in the saw-toothed concavo-convex shape described in claim 5. However, the uneven shape may be the rectangular shape described in claim 6. At this time, if the height of the “peak” of the rectangular convex portion or the depth of the “valley” of the concave portion is increased, the total area of the facing surface is further expanded, and more preferable frequency characteristics can be obtained.

Although the gap 4a is premised on the presence of air in this embodiment, a dielectric material, an insulating material, oil or the like may be infiltrated into the gap. By using such a sealing material, the capacitance of the signal transmission device is further increased and the frequency characteristic is improved. Moreover, the presence of the sealing material can prevent foreign matter from entering the gap. The narrow gap prevents the loss of these sealing materials due to capillarity. Furthermore, by sticking a sealing film (for example, conductive nylon) on the side surface of the signal transmission device, it is possible to prevent the sealing material from flowing out.

Iii) Signal Transmission Block FIG. 4 shows a connection diagram around the signal transmission device of the first embodiment. As shown in FIG. 4, the signal transmission block 100a is
The signal transmission device 1c shown in FIG. 3 and the matching units 8 and 9 are used. The inner coil 5 wound a predetermined number of times is connected to the matching box 8. The outer peripheral coil 6 wound a predetermined number of times is connected to the matching unit 9. The matching units 8 and 9 have predetermined impedances (for example, 50 [Ω]) so that the impedances of the inner coil 5 and the outer coil 6, which are appropriately changed depending on the wavelength, are adapted to the output impedance of the transmitter and the input impedance of the receiver. ). Since the impedance-converted signal transmission block 100a has impedance matching, a transmitter and a receiver can be directly connected to this block.

With respect to the length of the conductive wire of the coil wound around each element, with the manufacturing completed, with respect to the wavelength λ of the center frequency of the frequency band to be transmitted as described in claim 3, The lengths (n = 0, 1, 2, ...) Have a relationship of (n + 1/4) λ. For example, when n = 1, the wire length of the coil when the center frequency f _C is 380 [MHz] is

[0035]

[Equation 1] Becomes For example, the inner diameter DI is 12 [cm] and the outer diameter DO is 1
If it is 4 [cm], the conductive wire for the coil is the inner coil 5
Is wound around 1.7 times and the outer circumference coil 6 is wound around 2.3 times. However, the winding method of the coil is not limited, and a plurality of the same coils may be overlapped and wound, and the input and output of each coil may be mixed by a mixer or the like to achieve impedance matching. In this case, the signal level induced by the inductance is increased to obtain a more preferable result. What is important is to provide a coil that increases mutual inductance between the inner circumference coil and the outer circumference coil.

In manufacturing, considering the shortening rate of the total length of the conductive wire of the coil due to the influence (capacitance component) of the slack of the conductive wire, the fixing of the insulating material, etc., (n + 1/4) λ of the formula (1) Instead of, the wire is cut to about (n + 1/3) λ and the total winding length is (n
The length is equivalent to +1/4) λ.

Iv) Signal Transmission System FIG. 8 shows the first applied to the rotary type inspection apparatus of FIG.
The system diagram for signal transmission using the signal transmission apparatus of an Example is shown.

As shown in FIG. 8, the system for signal transmission is divided into a rotating section R and a fixed section F with the signal transmission block 100a shown in FIG. 4 as a boundary. Rotating portion R is a part which rotates together with the rotating shaft 22 of the rotary type inspection device 200, digital transmitter T ₁ through T _n to generate individual modulated digital signal, from the transmitter T ₁ through T _n A mixer 40 for mixing the signals, and the mixed transmission signal T
x is supplied to the signal transmission block 100a. Transmitter T ₁
˜T _n correspond to each of the CCD cameras 15, for example. The mixer 40 corresponds to the mixer 26 of FIG. 7, A / D-converts the signal from each camera 15, and mixes it as a digital signal.

The fixed section F is provided inside the control section 30 of FIG. 7, and is a distributor 42 for distributing the reception signal Rx output from the signal transmission block 100b into a plurality of parts and a mixing part in which a plurality of digital signals are mixed. Receivers R _{1 to} R _n that demodulate the digital signals of the respective transmitters from the signals.

Notwithstanding the above, it is not necessary that the rotating part R is the transmitting side and the fixed part F is the receiving side, and the fixed part F may be the transmitting side and the rotating part R may be the receiving side. Further, the fixed unit F and the rotating unit R may perform the transmission / reception operation.

Each of the transmitters T _{1 to} T _n has a digital signal generator 44 for generating a digital signal, and a digital signal from the digital signal generator 44 for FSK (Frequency Shift).
FSK modulator 46 for t keying) modulation.

Iv ) Receiver FIG. 9 shows a block diagram of the receiver. Since all the receivers have the same configuration, the receiver R _n will be taken as an example below.

As shown in FIG. 9, the receiver R _n demodulates each of the modulated digital signals of the frequency defined by the bandpass filter. The RF amplifier 50 amplifies the received signal Rx. The first bandpass filter 51 filters only predetermined frequency band data. The second bandpass filter 52 selects a signal in a narrower frequency band from the predetermined frequency band filtered by the first bandpass filter 51. The RF amplifier 53 amplifies the transmission signal whose frequency is selected. The 1/4 frequency divider 54 divides the transmission signal into a signal that is easily demodulated. The demodulator 55 directly detects the transmission signal in the data signal frequency band, demodulates it to the original digital signal, and outputs it. The amplifier 56 amplifies a signal in the data signal frequency band. The waveform shaping circuit 57
Shape a digital signal with'blurring 'into a square pulse. The line driver 58 current-amplifies the shaped digital signal, and a predetermined impedance (for example, 75
Output in [Ω]).

V) Attachment Mechanism FIG. 10 shows an example of an attachment mechanism for actually fixing the signal transmission device of the first embodiment in the antenna section 28 of FIG.

As shown in FIG. 10, the rotary shaft 22 forms the central axis of the rotary type inspection device 200. Bearing 61
And 62 are interposed between the rotation-side shield body 66 and the rotation shaft 22, and rotatably fix the rotation-side shield body 66. The bearings 63 and 64 are interposed between the fixed shield body 68 and the rotary shaft 22, and fix the fixed shield body 68 rotatably. The rotation side shield body 66 fixes the inner ring portion 2 of the signal transmission device 1c. Fixed side shield body 6
Reference numeral 8 fixes the outer ring portion 3 of the signal transmission device 1c. The rotating-side shield body 66 rotates relative to the fixed-side shield body 68. Therefore, the inner ring portion 2 and the outer ring portion 3 of the signal transmission device 1c also rotate relative to each other. For example, the receiving the transmission signal Tx ₁ is rotation-side shield member 66 through a signal transmission device 1c to be transmitted from the fixed side shield 68 signal Rx ₁
Is transmitted as. The transmission signal Tx ₂ transmitted from the rotation side shield body 66 is transmitted as a reception signal Rx ₂ to the fixed side shield body 68 via the signal transmission device 1c.

The signal transmission device of the present invention has a small volume, and the matching device can be stored inside the signal transmission device. For example, the matching device 8 on the rotation side can be provided in the area A (hatched) of FIG.

Description of Operation Next, the operation will be described. In FIG. 8, the CCD camera 15
Each of the transmitters T _{1 to} T _n provided in the above-mentioned device independently generates a digital signal. The transmitted data may be a control digital signal, position information, or the like. The digital signal generator 44 is specifically a microcomputer that controls each camera 15. The FSK modulator 46 FSK-modulates the digital signal. The modulated digital signal is usually 2
It has a bandwidth of about 0 [MHz]. However, the FSK modulator 46 can demodulate a digital signal even if the band is limited to about 10 [MHz].

Each transmitter T₁~ T_nAre different from each other
FSK-modulate the digital signal with the wave number. However, at the same time
The number of adjustable frequency bands, that is, the number of transmitters
Installable within the limit of flatness of frequency characteristics of unit 1c
Noh. Also, each transmitter T ₁~ T_nHave the same center frequency
Even if it is FSK modulated with a number and transmitted in a time division
Good. Each transmitter T₁~ T_nOutput is a predetermined output
It has an impedance (for example, 50 [Ω]). Mixer
40 is a modulated digital signal output from multiple transmitters
The signals are mixed and given impedance (eg 50
[Ω]) as a transmission signal Tx that matches the antenna unit 2
It outputs to the signal transmission block 100a in 8.

In the signal transmission block 100a shown in FIG. 4, the matching device 8 matches the transmission signal Tx with the impedance of the signal transmission device 1c itself. The inner peripheral coil 5 of the signal transmission device 1c generates a corresponding magnetic field according to the supplied transmission signal Tx. The inner ring portion 2 and the outer ring portion 3 of the signal transmission device 1c act on the inner peripheral coil 5 and the outer peripheral coil 6 in the same manner as the iron core of the transformer. That is, the inner ring portion 2 and the outer ring portion 3 formed of a conductive material strengthen mutual inductance between the inner peripheral coil 5 and the outer peripheral coil 6. Therefore, the change in the magnetic flux density due to the current flowing through the inner coil 3 is transmitted to the outer coil 3 with a small amount of attenuation. The outer peripheral coil 6 induces a current according to a change in the supplied magnetic flux density and generates a reception signal Rx. Between the facing surfaces S ₂ of the facing surfaces S ₁ and the outer ring portion 3 of the inner ring 2, a gap 4 shown in FIG. 3 (B)
It is considered that there is also a capacitive reactance component between the inner ring portion 2 and the outer ring portion 3 because of the electrostatic capacitance due to. The matching unit 9 performs impedance matching between the outer peripheral coil 6 and an external impedance (for example, 50 [Ω]), and outputs the impedance-converted reception signal Rx.

In FIG. 8, the distributor 42 is a signal transmission block.
The received signal Rx output from the clock 100a in a plurality of systems.
Distribute to. Receives each distributed digital signal
Machine R ₁~ R_nIs selected and demodulated.

The operation of the receiver will be described in detail with reference to FIG. The first bandpass filter 51 uses a helical coil having a high Q value, and has a predetermined frequency band component (for example, center frequency f _C = 250 [MHz], bandwidth BW ₁ = ± 3).
0 [MHz]) only. The second band-pass filter 52 has a narrower frequency band (for example, a bandwidth BW).
₂ = ± 10 [MHz]). Both band-pass filters enhance the attenuation characteristic, which can be expected to be a small value when only passive elements are used, by the action of a plurality of filters, and as a result, select only the frequency band of a specific FSK modulated signal. If a SAW (Surface Acoustic Wave) filter is used instead of using the first bandpass filter 51 and the second bandpass filter 52, a sharp selection characteristic can be obtained with only one filter. The 1/4 frequency divider 54 divides the selected frequency by 4 in order to obtain an appropriate frequency for stable demodulation operation.
Reduce to 1 /. The demodulator 55 FSK demodulates the received signal whose frequency has been divided by 1/4, and obtains a digital signal before modulation. Since the received signal has a narrow band of, for example, 10 [MHz], the demodulated signal has a greatly distorted waveform. Therefore, the waveform shaping circuit 57 limits the demodulated received signal. To make a square wave.

Description of Characteristics FIGS . 11A and 12 show the transmission characteristics of the signal transmission device of the first embodiment. FIG. 11A shows the relationship between the relative rotation angle between the inner ring portion 2 and the outer ring portion 3 and the signal strength of the received signal. As can be seen from the figure, the change in the intensity of the received signal depending on the angle is suppressed within ± 5 [dB]. If the transmission signal is strong enough to demodulate stable digital data even when the received signal strength is the minimum, the rate of change can be obtained at a highly sensitive angle, especially when the transmission signal is a digital signal. Since the signal amplitude value is saturated, there is no fluctuation in the overall signal amplitude and there is no practical problem.

FIG. 12 shows frequency characteristics. As shown in FIG. 12, the attenuation characteristic of the transmission signal is improved. For example, in the FSK modulation data having a center frequency of 250 [MHz], when the bandwidth BW is set to 20 [MHz], the attenuation rate of the center value within the bandwidth BW is within 1 [dB]. Therefore, in this range, it is possible to sufficiently demodulate digital data. The attenuation amount of the signal level in the range of 100 [MHz] to 500 [MHz] is about 15 [dB], and the attenuation curve is slow. The signal transmission device of this embodiment can be applied as a signal transmission device used for data transmission in this range.

FIG. 13 shows the reception characteristic of the first embodiment. As shown in FIG. 13, the received signal level is −7 when there is no signal.
It is about 0 [dbm] and the signal level at the time of signal reception is -3.
If it is 0 [dbm] or more, the signal can be sufficiently extracted. As a practically usable transmission rate, the signal transmission apparatus of this embodiment is suitable for a data communication rate of about 1 [Mbps] at 250 [MHz].

Further, the impedance between both elements is low due to the presence of the capacitive reactance component. For example, an actually measured impedance of about 5 [Ω] at 1 [kHz] can be realized. The emission of radio waves from the signal transmission device itself (so-called unnecessary radiation) is a very small amount leaking from the gap, so it can be blocked by using a shield body together.

Further, the matching unit 8 can be constituted by only a simple coil, and the volume of the matching unit 8 can be reduced when installed, so that the substrate can be installed in the space existing on the inner peripheral side of the inner ring portion 2. It is possible to provide a small signal transmission device whose impedance is matched.

Effects As described above, according to the signal transmission device of the first embodiment, since the transmission signal level is high, it is possible to efficiently perform signal transmission with a small output.

Further, the signal transmission device of the first embodiment can be made smaller than the conventional signal transmission device, and the volume capacity of the antenna portion 28 and the like itself can be made smaller. Therefore, signal transmission that is strong against noise can be realized.

Since the signal transmission device of the first embodiment uses the signal transmission utilizing the inductance component,
It exhibits low impedance at relatively low transmission frequencies and is considered to improve noise resistance.

On the other hand, according to the receiver disclosed in the present embodiment, since direct detection is possible without using a local oscillator, wide band detection is possible, which is peculiar to heterodyne generated when the heterodyne system is used. No beat failure occurs. Further, compared to the case of adopting the super reproduction reception system, the operation stability is high, the circuit is simple, and the receiver itself can be downsized. (II) Second Embodiment In a second embodiment of the present invention, the first signal transmission device having the rectangular facing surface of claim 6 is added to the signal transmission device of claims 1, 2 and 4. It is applied to a rotary type inspection apparatus similar to the embodiment. Of course, in addition to the rectangular facing surface described in claim 6, the sawtooth facing surface according to claim 5 or the like can be applied.

Description of Configuration Since the rotary type inspection device and the signal transmission system are the same as those of the first embodiment shown in FIG. 7, the description thereof will be omitted.
The signal transmission device of this embodiment is stored in the antenna unit 28.

FIG. 5 shows a block diagram of a signal transmission device according to a second embodiment of the present invention. 7A is a front view and a side view of the signal transmission device 1d according to the present embodiment, and FIG. 9B is a cross-sectional structural view taken along the alternate long and short dash line in FIG.

I) Signal Transmission Device Main Body As shown in FIG. 5A, the signal transmission device 1d of the embodiment
Is a signal transmission device main body 1b according to claim 5 of FIG. 1 provided with terminals and an insulating material, and an inner ring portion 2b in which a main body portion acting as an antenna is formed of iron (Fe).
And the inner ring portion 2b is constituted by an outer ring portion 3b formed of aluminum (Al) that can be relatively rotated with a predetermined gap 4b therebetween. The inner ring portion 2b has an inner diameter DI of 12 cm, and the outer ring portion 3 has an outer diameter DO of 14 cm, for example.

As shown in FIG. 5B, feeding points TI _{1 to} TI ₄ are provided on the inner peripheral surface of the inner ring portion 2b to electrically connect the inner ring portion 2a to the outside. Feeding points TO _{1 to} TO ₄ are provided on the outer peripheral surface of the outer ring portion 3b to electrically connect the outer ring portion 3b to the outside. Each of the feeding points may be connected with a conductive wire by a method such as soldering. Alternatively, a terminal may be provided and a conductive wire may be connected to the terminal. After providing the feeding point, the insulating material 7 is provided.

The shape of the insulating material 7 is similar to that of the first embodiment. Further, the conductive material, the concavo-convex shape, and the sealing material used in the inner ring portion 2b and the outer ring portion 3b are the same as those in the first embodiment, and thus the description thereof will be omitted.

The number of feeding points is not limited to four points as described above, and the number of feeding points can be increased within a volumetric limit. As the number of power feeding points increases, the difference in the voltage distribution in each part of the signal transmission device can be more averaged, and the characteristic variation due to the relative angle between the inner ring part and the outer ring part can be reduced.

Ii) Signal Transmission Block FIG. 6 shows a connection diagram of the signal transmission device of the second embodiment. Figure 6
As shown in FIG. 5, the signal transmission block 100b is composed of the signal transmission device 1d and the baluns 10 and 11 shown in FIG.

The balun 10 has coils L _{1 to} L ₃ . The coil L ₂ is connected to the feeding points TI ₁ and TI ₄ . The balun 11 has coils L _{4 to} L ₆ . The coil L ₄ is connected to the feeding points TO ₁ and TO ₄ .

Since the balun 10 is composed of a small coil and has a small volume, the balun itself is integrated with the signal transmission device 1d by providing a substrate in the space of the inner peripheral portion of the signal transmission device 1d. can do.

Description of Operation Since the outline of the signal flow is as described in the first embodiment, only the operation before and after the signal transmission block 100b will be described.

In FIG. 8, the frequency-mixed transmission signal Tx is supplied to the signal transmission block 100b. In FIG. 6, the balun 10 supplies the transmission signal Tx supplied from the mixer 40 on the transmitter side to the coil L ₁ . Coil L
₁ is the coil L ₂ and L due to the action of mutual inductance
_Direct the transmitted signal to ₃ . The coil L ₂ supplies signals to the feeding points TI ₁ and TI ₄ . The coil L ₃ is a feeding point TI ₂
And supplies a signal to the TI _3.

The inner ring portion 2b and the outer ring portion 3b have a facing surface S _1b having a large area, the gap 4b, and the facing surface S of the outer ring portion 3b.
_2b has a capacitive reactance component. for that reason,
Since the transmission signal Tx dispersed and fed to the feeding points TI _{1 to} TI ₄ of the inner ring portion 2b is a high frequency signal, it is transmitted to the outer ring portion 3b with low impedance. The transmitted signal has a different voltage distribution in each portion of the outer ring portion 3b depending on the transmission frequency, but the plurality of feeding points TO are evenly provided.
The voltage distribution of each part can be extracted by _{1 to} TO ₄ .

The balun 11 is a feeding point TO of the outer ring portion 3b.₁When
TO_FourAnd the coil L_FourTo the power feed point TO₂And TO₃
And the coil L_FiveConnect to. Coil L₆Is an external impediment
Impedance matching impedance (for example, 50 [Ω])
Has a coil L_FourAnd L _FiveMutual inductance with
Feed point TO₁~ TO_FourThe signal obtained from
The received signal Rx is mixed and impedance matched.
Output to the outside.

As described above, the reception signal Rx obtained by averaging the voltage distribution of the transmission signal is supplied to the distributor 42 in FIG. Description of Characteristics FIGS . 11B and 12 show characteristics of the signal transmission device according to the second embodiment.

FIG. 11B shows the relationship between the relative angle and the signal strength, and FIG. 12 shows the frequency characteristic. Also in this embodiment, a transfer characteristic sufficient for signal transmission can be obtained as in the first embodiment. Also in the signal transmission device of the present embodiment, a low impedance of 5 [Ω] or less at 1 [kHz] is actually measured. As a practically usable transmission speed, the signal transmission device of this embodiment is suitable for a data communication speed of about 1 [Mbps] at 250 [MHz].

Further, by storing and integrating the balun in the space on the inner peripheral side of the inner ring portion, it is possible to provide a signal transmission device that can use impedance-matched transmission signals. By providing a large number of feeding points, it is possible to further reduce the fluctuation rate of the received signal strength for each rotation shown in FIG. 11 (B).

Effects As described above, according to the signal transmission device of the second embodiment, it is possible to supply a stable transmission signal with little fluctuation in the signal level due to the relative rotation of the elements. Other Modifications The present invention is not limited to the above-described embodiments, and various modifications can be made.

In the above embodiment, the signal transmission device having a rectangular or sawtooth facing surface shape was used, but other shapes can be applied as long as the surface area can be increased. For example, a sine wave shape, a trapezoidal shape, or the like is possible.
It is further preferable that the rectangular signal transmission device is a combination of simple flat plates with narrow widths of both rectangles, and an electrode plate shape similar to a so-called air capacitor (variable capacitor).

The dimensions of the signal transmission device are merely examples, and can be changed according to the frequencies of other transmission signals. The signal transmission device according to the embodiment is premised on the relative rotation operation between the inner ring portion and the outer ring portion, but the invention is not limited to the rotation operation, and is also applicable to elements that perform parallel movements. For example, one element is fixed and has a long overall length,
The signal transmission device of the present invention can be applied even when the other element having a short overall length slides on it.

The modulation system used for transmission was FSK modulation in the above embodiment, but other modulation systems such as PS
K (Phase Shift Keting), ASK (Amplitude Shift)
Keying), QAM (Quadrature Amplitude Modulayion)
) And other modulation methods can be applied. However, ASK has a problem in noise resistance. Other Embodiments In the signal transmission device according to any one of claims 2 to 4, a plurality of flat plates are erected on each of the opposing surfaces so as to be parallel to a tangential direction of relative rotation, and between the flat plates of one of the opposing surfaces. A plurality of flat surfaces are staggered on the other facing surface so that the flat surface of the other facing surface is interposed in the gap of, and either of the flat surfaces of one facing surface is the flat plate of the other facing surface or the other element body. Signal transmission devices that are close to each other with a predetermined gap so as not to contact each other exhibit preferable characteristics.

According to the above-mentioned signal transmission device, the inner ring portion and the outer ring portion exhibit high electrostatic capacitance like an air condenser, and a high frequency signal of a predetermined frequency can be efficiently transmitted from one side to the other side.

According to such a signal transmission device, it is possible to provide a small signal transmission device having a high transmission efficiency.

[0083]

As described above, according to the first and second aspects of the present invention, the impedance between the two elements facing each other is reduced due to the concavo-convex shape that enlarges the total area. Thus, it is possible to provide a signal transmission device exhibiting suitable transmission characteristics that is not affected by external noise even if the overall size is small.

According to the invention described in claim 3, the transmission efficiency is most preferable for each of both elements (n + 1).
/ 4) Since the coil having the length of the wavelength (n = 0, 1, 2, ...) Is provided, the mutual inductance between both coils is increased, and the transmission characteristics are efficient. Further, since there is a capacitive component due to the gap between the elements, the overall impedance can be lowered and a signal transmission device having excellent noise resistance can be provided in a size smaller than the conventional size.

According to the invention described in claim 4, since a plurality of feeding points are provided in both elements, the difference in the voltage distribution caused by the change in the relative position between the elements is averaged, Transmission of almost constant signal strength can be performed regardless of the rotation angle of the element. Further, according to the present invention, since both elements are coupled by the capacitive reactance, the efficiency is not lowered even for a high frequency signal, and a signal transmission device having high noise resistance performance can be provided.

According to the fifth aspect of the present invention, since the facing surfaces S _1a and S _2a have sawtooth shapes, the surface area is large and the gap 4 between both elements is small even if the overall size is small.
a can be made small. Therefore, it is possible to provide a signal transmission device having a low impedance and less susceptible to the influence of external noise.

According to the sixth aspect of the invention, since the facing surfaces S _1b and S _2b have a rectangular shape, the surface area is large and the gap 4b between both elements can be made small even if the overall size is small. Therefore, it is possible to provide a signal transmission device having a low impedance and less susceptible to the influence of external noise.

[Brief description of drawings]

FIG. 1 is a signal transmission device having a sawtooth-shaped facing surface, in which (A) is a perspective view and (B) is a sectional structural view.

FIG. 2 is a signal transmission device having a rectangular opposing surface,
(A) is a perspective view and (B) is a cross-sectional structural view.

FIG. 3 is an explanatory diagram of a signal transmission device according to a first embodiment,
(A) is a front view / side view, and (B) is a cross-sectional structural view.

FIG. 4 is a connection diagram of the signal transmission device according to the first embodiment.

FIG. 5 is an explanatory diagram of a signal transmission device according to a second embodiment,
(A) is a front view / side view, and (B) is a cross-sectional structural view.

FIG. 6 is a connection diagram of a signal transmission device according to a second embodiment.

FIG. 7 is an overall view of a rotary inspection device to which the signal transmission device of the present invention is applied.

FIG. 8 is an overall connection diagram of the signal transmission devices of the first and second embodiments.

FIG. 9 is a block diagram of a receiver.

FIG. 10 is an example of a mounting mechanism of the signal transmission device of the first and second embodiments.

FIG. 11 is a relationship between the relative angle and the signal strength of the signal transmission device of the embodiment, (A) is the signal transmission device of the first embodiment,
(B) is a characteristic relating to the signal transmission device of the second embodiment.

FIG. 12 is a frequency characteristic diagram of the example.

FIG. 13 is a reception characteristic diagram of the embodiment.

FIG. 14 is an explanatory diagram of a conventional signal transmission device.

FIG. 15 is a transmission characteristic diagram of a conventional signal transmission device,
(A) is a relationship between relative angle and signal strength, (B) is a frequency characteristic diagram.

[Explanation of symbols]

H ... Conveyor B ... Work bottle 1a, 1b, 1c, 1d ... Signal transmission device 2a, 2b ... Inner ring part 3a, 3b ... Outer ring part 4a, 4b ... Gap 5 ... Inner circumference coil 6 ... Outer circumference coil 7 ... Insulating material 8 , 9 ... Matching device 10, 11 ... Balun (mixing / distributor) 12 ... Entrance star wheel 13 ... Endoscope 14 ... Base 15 ... CCD camera 16 ... Rotation inspection stand 17 ... Shaft 18 ... Cam follower 19 ... Cam 20 ... Rotating disk 22 ... Rotating shaft 24 ... Camera selector 26 ... Mixer 28 ... Antenna section 30 ... Control section 32 ... Inspection section 34 ... Rotating resolver 36 ... Fixed resolver 40 ... Mixer 42 ... Distributor 44 ... Digital signal generator 46 ... FSK Modulators 50, 53 ... RF (Radio Frequency) amplifier 51 ... First bandpass filter 52 ... Second bandpass filter 54 ... Quarter frequency divider 55 ... Recovery Controller 56 ... Amplifier 57 ... Waveform shaping circuit 58 ... Line driver 60 ... Rotating shafts 61 to 64 ... Bearing 66 ... Fixed side shield body 68 ... Rotating side shield body 100a, 100b ... Signal transmission block 101 ... Transmitting element 102 ... Receiving element 200 ... rotary type inspection device T ₁ through T _n ... transmitter R ₁ to R _n ... receiver

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toyokazu Sano, 376-1, Shinkochuo, Ishikari-cho, Ishikari-gun, Hokkaido 6-7 6 Force Co., Ltd. (72) Takeo Oe 3-766-1, Shinkochuo, Ishikari-cho, Ishikari-gun, Hokkaido Company Force

Claims (6)

[Claims] 1. A signal transmission device having two transmission / reception elements, which are relatively movable while facing each other with a predetermined space therebetween, wherein the two transmission / reception elements are made of a conductive material. A signal transmission device, wherein each of the facing surfaces facing each other is formed in an uneven shape that increases the total area of the facing surface. 2. A signal transmission device having two transmission / reception elements, which are movable while facing each other with a predetermined space therebetween, wherein the two transmission / reception elements are made of a conductive material. Is a ring-shaped object that relatively rotates around the same center of rotation, and has an outer ring portion located on the outer peripheral side of the predetermined gap and an inner ring portion located on the inner peripheral side of the predetermined gap. , And each of the facing surfaces of the outer ring portion and the inner ring portion, which face each other, are formed in a concavo-convex shape that increases the total area of the facing surface. Signal transmission equipment. 3. The signal transmission device according to claim 2, wherein each of the outer peripheral end surface of the outer ring portion and the inner peripheral end surface of the inner ring portion has a signal wavelength λ at a center frequency of a transmission frequency band to be transmitted and received, (N + 1/4) λ (n = 0,
1, 2, ...) A signal transmission device comprising a coil containing a conductive material, the winding length of which is adjusted so as to have a corresponding length. 4. The signal transmission device according to claim 2, wherein the outer ring portion and the inner ring portion are provided with a plurality of feeding points for electrically connecting to an element body, and between the respective feeding points. A signal distributor or a signal from each of the feeding points is mixed, and a matching device interposed between the feeding points to match the impedance to the outside is provided, respectively. Characteristic signal transmission device. 5. The signal transmission device according to claim 1, wherein the concavo-convex shape of each of the facing surfaces is formed in a sawtooth shape, and the convex portion of one of the facing surfaces and the other of the facing surface of the other facing surface are formed. A signal transmission device, wherein the recesses are close to each other with the predetermined gap in a positional relationship such that the recesses are engaged with each other. 6. The signal transmission device according to claim 1, wherein the concavo-convex shapes of the respective facing surfaces are formed in a rectangular shape,
A signal transmission device, wherein one of the convex portions of the facing surface and the concave portion of the other facing surface are close to each other with the predetermined gap in a positional relationship such that they are intermeshed with each other.