JPH0722828A - Rotation transmission structure - Google Patents

Abstract

PURPOSE:To provide the simple rotating transmission structure which is capable of easy impedance matching in a wide band and has a small loss and does not require the precision for assembling. CONSTITUTION:A plug 11 is provided in the center of a rotating part support base 7 fixed to a fixing part 1, and a first conductor plate 10-1 is electrically connected to the center conductor of this plug 11. The other side of a bearing 9 attached to a fixing ring 8 fixed to the rotating part support base 7 is attached to the inside of a pulley 15 to support a rotating part 2 rotatably to the fixing part 1. A plug 12 is attached to the center part of this rotating part 2, and a second conductor plate 10-2 is connected to the center conductor of this plug 12 so as to face the first conductor plate 10-1. The signal impressed to the plug 12 is rotatably transmitted to the plug 11 by a capacitive coupler consisting of these first and second conductor plates 10-1 and 10-2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transmission structure for transmitting a signal from a rotatably supported directional antenna to a receiver, and particularly to an automatic tracking satellite antenna for a mobile body. Is suitable.

[0002]

2. Description of the Related Art In recent years, broadcasting has been carried out using satellites. However, since the received electric field when receiving this satellite broadcasting on the ground is small, it has a directional characteristic as an antenna for receiving satellite broadcasting. Reception is performed using a sharp high-gain antenna. Therefore, in order to watch the satellite broadcast while riding on the moving body, an automatic tracking satellite antenna that can automatically point the antenna in the direction of the satellite is required. In such an automatic tracking satellite antenna, the antenna rotates with the traveling of the moving body, but the receiver is fixed.Therefore, a rotary transmission structure for transmitting the reception signal from the antenna from the rotating part to the fixed part is required. Become.

A conventional example of such a rotary transmission structure is shown in FIG. 3 and will be described with reference to this figure. In this figure, 100 is a moving body, and a fixing portion 1 for fixing the antenna of the automatic tracking antenna to the roof of the moving body 100.
01 is installed. The fixed portion is provided with a rotation support base 107, and the rotation unit 102 is rotatably fixed to the rotation support base 107. A bearing 109 is used as a mechanism for rotatably fixing the rotating unit 102. The bearing 109 is attached to the rotating shaft of the rotating unit 102, and a pulley 108 is provided on the outer circumference of the bearing 109. The belt 11 is provided between the pulley 108 and the pulley 111 provided in the drive unit.
When 0 is applied and the pulley 106 is rotationally driven by the motor 106, the pulley 108 is rotationally driven.

Further, on the rotating portion 102, for example, BS
A plurality of directional antennas 103 for receiving broadcasting are provided, and down converters 104 for converting the frequency of the received signal are provided on the back side of the directional antennas 103, respectively. This plurality of down converters 10
The output signals from 4 are combined in phase by the in-phase combiner 105. Although a mechanism for automatically tracking the antenna is not shown, the motor 106 is driven so that the reception output of the received satellite broadcast becomes maximum, and the pulley 111 is rotationally driven by driving the motor 106. Then,
Since the pulley 108 is driven via the belt 110,
The rotating unit 102 is rotated so that the antenna 103 faces the satellite.

FIG. 4 shows an enlarged structure of the rotary shaft. In this figure, a bearing 109 is rotatably attached to a rotation support base 107 provided on the fixed portion 101, and the bearing 107 is attached to the rotation portion 102.
Is stuck to. Further, a pulley 108 is provided on the outer circumference of the bearing 107. Further, a non-magnetic rotation center body 112 is provided at the rotation center of the rotating portion 102, and a coil 113 is arranged outside the rotation center body 112. The signal from the in-phase combiner 105 is applied to this coil.

On the other hand, a pipe 115 made of a non-magnetic material is provided on the rotation support base 107, and a coil 114 is provided outside the pipe 115 so as to face the coil 113. This coil 114 is connected to a tuner of a receiver (not shown). Since the rotation center body 112 and the pipe 115 have a cylindrical shape, the coil 113 and the coil 114 are always opposed to each other even when the rotating unit 102 rotates. Therefore, the coil 113 and the coil 114
Will be electromagnetically coupled to each other, and the magnetic field generated by the signal applied to the coil 113 will cause the coil 1 to
A current signal is induced in 14 and the induced current signal is input to the receiver. Since the coil 113 and the coil 114 are electromagnetically coupled regardless of the rotation of the rotating unit 102, the rotation transmission structure can be formed by the configuration shown in FIG.

[0007]

However, such electromagnetic coupling is so-called L (inductance) coupling, and since the inductance is used, the impedance becomes high when the signal frequency becomes high, so that it becomes wide band. The impedance matching of
There is a problem that the signal is attenuated in the high frequency part. Furthermore, if impedance matching is performed by using a resistor or the like for widening the band, there is a problem that the transmission loss increases.

If the two coils used for electromagnetic coupling are not arranged coaxially, the coupling coefficient between the coils changes as the rotating part rotates and the amplitude of the output signal fluctuates. Although it is necessary to fabricate two coils, it is necessary to perform precise processing to arrange them on the same axis, which causes a cost increase. Therefore, an object of the present invention is to provide a rotary transmission structure having a simple structure in which impedance matching can be easily achieved over a wide band, there is little loss, and assembly does not require precision.

[0009]

In order to achieve the above object, the present invention reduces the frequency of a received signal to several tenths and arranges two conductive plates to face each other at a portion of a rotary shaft. Then, the signal is transmitted from the rotating portion to the fixed portion via the capacitive coupler constituted by the two conductive plates.

[0010]

According to the present invention, since the frequency of the signal transmitted by the rotary transmission structure is converted into a low frequency and the capacitive coupling is used, impedance matching can be easily achieved over a wide band, and the transmission loss is relatively low. Can be reduced. Further, it is ideal that the two conductive plates are arranged coaxially, but even if there is some eccentricity, there is little change in the capacitance due to rotation, and the parallelism of the two conductive plates is slightly broken. However, there is no change in capacity with rotation. Therefore, changes in the amplitude of the output signal due to these factors can be considered to be problem-free. Therefore, it is not necessary to carry out processing with high precision and assembling with high precision, and the cost can be greatly reduced due to the simple structure.

[0011]

FIG. 1 shows an embodiment of the rotary transmission structure of the present invention. In this figure, 1 is a fixed part, which is attached to a roof of a moving body. The fixed portion 1 is provided with a rotary portion support base 7, and a fixed ring 8 that supports a bearing 9 is attached to the upper surface of the rotary portion support base 7. Further, a through hole is provided in the central portion of the upper surface of the rotating part support base 7, and the first coaxial connector 11 is fixed so as to penetrate the through hole. The first conductor plate 10-1 is electrically connected to the central conductor of the first coaxial connector 11.

A motor 6 is further attached to the fixed portion 1, and a gear 13 is attached to the rotating shaft of the motor 6, and the gear 13 is attached to a gear 14 having a large diameter attached to a bearing 9. It is in mesh. This large-diameter gear 14 is fixed to the fixed ring 8 via the bearing 9.
Is rotatably supported with respect to, and the rotation unit 2 is rotated by rotationally driving the gear 14,
The gear 14 is attached to the lower surface of the rotating portion 2. A plurality of directional antennas 3 for receiving satellite broadcasts are arranged on the rotating unit 2 at positions that do not shade each other's radio waves, and the directional antennas 3 are received on the back surface of each of the plurality of directional antennas 3. The frequency of the satellite broadcast signal is, for example, 1.3 GHz
A converter 4 is provided for converting into bands.

The plurality of satellite broadcast signals converted by the converter 4 are converted to a frequency of about 400 MHz band, combined in phase by the in-phase combining circuit 5, and further attached to the central portion of the rotating portion 2. Is supplied to the coaxial connector 12. The second conductor plate 10-2 is electrically connected to the center conductor of the second coaxial connector 12. Then, as shown in the figure, the first coaxial connector 11 and the second coaxial connector 12 are attached to the rotary unit support base 7 and the rotary unit 2 respectively so as to be coaxially arranged. The conductor plate 10-1 and the second conductor plate 10-2 are coaxially arranged and are arranged so as to face each other. Therefore, a capacitance is formed between the first conductor plate 10-1 and the second conductor plate 10-2, and the satellite broadcast signal supplied to the plug 12 is transmitted to the plug 11 via this capacitance. Become so.

In this case, the capacitance of the capacitive coupler composed of the first capacitance plate 10-1 and the second capacitance plate 10-2 is, for example, 1
The frequency of the signal to be transmitted is about 400
Since it is converted to MHz, the transmission loss becomes small. Further, the first conductor plate 10-1 and the second conductor plate 1
The space in which 0-2 and 0-2 are arranged is a conductive rotating part support 7
Of the fixed ring 8 and the lower surface of the rotating portion 2 are formed in the shielded space.
Since the conductive plates 10-1 and 10-2 are arranged, it is possible to reduce the influence of noise or the like.

Even if the first conductive plate 10-1 and the second conductive plate 10-2 are assembled with some eccentricity, a predetermined capacity proportional to the area where they face each other can be generated. , It does not hinder the signal transmission.
Further, even if it is eccentric, the change in the opposing area is small when the rotating unit 2 rotates, and the change in the capacitance is small, so that the change in the amplitude of the signal due to the rotation of the rotating unit 2 affects the signal processing. Not so much. Further, it is desirable that the surfaces of the first conductive plate 10-1 and the second conductive plate 10-2 are arranged in parallel, but even if the parallelism is a little broken in the assembled state, a predetermined level is obtained. Since the capacity can be generated, it does not hinder the signal transmission. Further, in this case, the capacitance does not change with the rotation of the rotating unit 2, and the signal amplitude does not change with the rotation.

Next, FIG. 2 shows a half sectional view of the rotary transmission structure shown in FIG. However, this drawing shows an example in which a pulley is used as the means for applying the rotational driving force to the rotating portion 2 instead of the gear. In this figure, a flange portion of a cylindrical rotation support base 7 having a flange is fixed to the upper surface of the fixed portion 1, and a fixing ring 8 supporting one of the bearings 9 is attached to the flange portion. A connector 11 is attached to the central portion of the connector. A rod-shaped mounting portion protruding from substantially the center of the disk-shaped first conductor plate 10-1 is electrically connected to the central conductor of the first plug.

The other of the bearings 9 is fixed to the pulley 15, and the pulley 15 is rotatably supported by the fixed portion 1. The pulley 15 is attached to the lower part of the rotating unit 2, and the rotating unit 2 is rotated as the pulley 15 rotates. Further, the second coaxial connector 12 is fixed to the central portion of the rotating portion 2,
A rod-shaped mounting portion protruding from substantially the center of a disk-shaped second conductor plate 10-2 is electrically connected to the central conductor of the second coaxial connector 12. The disk-shaped second conductor plate 10-2 and the first conductor plate 10-1 are arranged to face each other as shown in the drawing. Then, as described above, a capacitance is generated between the first conductor 10-1 and the second conductor 10-2, and therefore the rotatable second conductor plate 10 is used.
-2, the signal supplied to the first fixed conductor plate 10-
1 will be transmitted.

The first and second conductive plates 10-1,
The shape of 10-2 is not limited to a disc shape, and may be a polygonal shape. Further, the central conductors of the plugs 11 and 12 and the first and second conductors
The conductive plates 10-1 and 10-2 may be integrally formed, and the rod-shaped mounting portion may be inserted into the contact plugs 11 and 12 as a central conductor. The ground of the second connector is grounded by being electrically connected to the grounded fixing portion 1 via the conductive bearing 9. In addition, as described above, the space portion where the first conductive plate 10-1 and the second conductive plate 10-2 are arranged has the shield structure. In the example shown in FIG. 2, the rotating portion 2 is driven by a pulley, but the drive may be either a gear drive or a pulley as desired. Further, although the motor 6 is attached to the fixed portion 1 as shown in FIG. 1, the motor 6 may be attached to the rotating portion 2.

The fixed part 1 of the directional antenna 3 using the rotary transmission structure constructed as described above is attached to the roof of a moving body, and the rotary part 2 is arranged so that the received signal transmitted from the fixed part becomes maximum. By rotatably driving the directional antenna 3, the directional antenna 3 can be automatically oriented toward the satellite. Also, if the moving body is equipped with a device that can accurately measure the current position and direction, the direction of the satellite is known in advance,
Based on this data, the antenna can be directed towards the satellite.

[0020]

As described above, according to the present invention, since the frequency of the signal transmitted by the rotary transmission structure is converted into a low frequency, and the capacitive coupling is used, impedance matching can be easily achieved over a wide band. Moreover, the transmission loss can be relatively reduced. Further, even if the two conductive plates have some eccentricity, there is little change in capacitance with rotation, and even if the parallelism of the two conductive plates is slightly broken, there is no change in capacitance with rotation. The change in the amplitude of the output signal caused by can be minute. Therefore, it is not necessary to carry out processing with high precision and assembling with high precision, and the cost can be greatly reduced due to the simple structure.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a rotary transmission structure of the present invention.

FIG. 2 is a perspective view of a rotary transmission structure according to an embodiment of the present invention in a half sectional view.

FIG. 3 is a diagram showing a conventional rotary transmission structure.

FIG. 4 is a view showing a rotary shaft portion of a conventional rotary transmission structure.

[Explanation of symbols]

 1, 101 Fixed part 2, 102 Rotating part 3, 103 Antenna 4, 104 Converter 5, 105 In-phase combining part 6, 106 Motor 7 Rotating part support base 8 Fixing ring 9, 109 Bearing 10-1, 10-2 Conductive plate 11 , 12 Plug 13,14 Gear 15,108,111 Pulley 107 Rotation support base 110 Belt 112 Rotation center body 113,114 Coil 115 Pipe

Claims (4)

[Claims] 1. A plurality of directional antennas, a plurality of converters that respectively convert the frequencies of signals received by the plurality of directional antennas, and an in-phase combiner that combines the outputs of the plurality of converters in phase. A rotating unit provided, a non-drive unit fixed to the lower portion of the rotating unit, and rotatably attached to the rotation supporting unit via a bearing, and a drive for driving the non-drive unit to rotate. Means, a fixed portion to which the rotation support means is attached, and a capacitively coupled first conductive plate and second conductive plate that are provided so as to face the rotation shaft portion of the rotation support means. Attaching the first conductive plate to the fixed part and the second conductive plate to the rotating part, and transmitting the output signal of the in-phase combiner supplied to the second conductive plate to the fixed part. Rotation transmission structure, wherein Rukoto. 2. The rotating body transmission structure according to claim 1, wherein the first conductor plate and the second conductor plate are formed in a circular shape or a polygonal shape. 3. The space in which the first conductor plate and the second conductor plate are mounted is shielded by the rotation support means, the bearing, and the rotating portion. The described rotational transmission structure. 4. The fixed part for supporting the directional antenna is mounted on a moving body, and the antenna is always directed in a predetermined direction by driving the drive means with an automatic tracking signal. Claims 1 to 3
The rotation transmission structure according to any one of 1.