JP2009009796A - Rotary joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary joint preventing degradation of efficiency of optical transmission. <P>SOLUTION: A rotating body part 21 is provided with a conductive ring 6, and a light-transmitting light guide tube 19, while, a rotary part 2 is provided with a laser diode 13 or a photo diode 16 at one of the end part sides of the light guide tube 19. A fixed part 3 is provided with a conductive ring housing 12 with a conductive brush 8 fixed inside and housing a conductive ring 6, a photo diode 16 or a laser diode 13 at the other end part side of the light guide tube 19, a light-transmitting housing 18 housing the photo diode 16 or the laser diode 13 as well as the other end part of the light guide tube 19, and a light-shielding wall 20 fitted between the conductive ring housing 12 and the light-transmitting housing 18 so as not to interfere light transmission carried out between the photo diode 16 or the laser diode 13 of the other end part side and the other end part of the light guide tube 19 and to shield infiltration of lubricant applied to a bearing and the conductive ring toward inside of the light transmission housing 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary joint that performs signal transmission over a fixed portion and a rotating portion that is rotatably combined with the fixed portion, and in particular, uses transmission by sliding contact between a brush and a conductive ring and transmission by an optical signal in combination. Regarding rotary joints.

  Many surveillance camera devices that are fixedly installed on an indoor ceiling or the like that perform monitoring while changing the imaging direction by controlling the pan angle and tilt angle of the camera are widely used. Such a surveillance camera device capable of angle control has a configuration in which a fixed part fixedly installed on a ceiling or the like and a movable part rotatable in the pan direction are connected via an electric pan head. There are many things. That is, in the surveillance camera device, a movable part equipped with a camera equipped with a tilt drive mechanism that rotates in the tilt direction is attached to one (movable part) of the electric pan head that can rotate in the pan direction, and the electric cloud. In many cases, the base (the fixed portion) is attached to one of the fixed portions, and the other fixed portion is fixedly installed on the ceiling or the like. In the surveillance camera device having such a configuration, the video signal output from the camera mounted on the movable unit is transmitted to the fixed unit via the electric camera platform, and image processing and output interface conversion are performed in the fixed unit. After that, it is output to an external monitor or video signal recording device.

  Several methods are known for the electric camera platform used in such a monitoring camera device. Particularly, as an electric camera platform capable of continuously turning the movable part in the pan direction, a slip ring, It is known that a signal connection path extending between the swivel portion and the fixed portion is constructed by a sliding contact with the brush. However, with this sliding contact method, the oil film or dust adheres to the contact part between the swiveling slip ring and the fixed brush, resulting in unstable electrical contact or noise associated with mechanical contact. There are problems such as deterioration of electrical contact performance due to long-term continuous sliding. In particular, in the case of a video signal, the occurrence of malfunction due to the occurrence of noise accompanying rotation and the control signals for panning and tilting control are problematic. Furthermore, since the frequency band that can be transmitted is limited by such a mechanical contact method, it has been difficult to transmit high-definition video signals and high-speed data.

  Therefore, in Patent Document 1, the sliding contact by the slip ring and the brush and the light transmission are used together, and the video signal transmission path of the camera is replaced with the sliding contact of the slip ring and the brush, and the transmission path provided on the rotating shaft portion. Has proposed an electric pan head that performs optical signal transmission.

In the electric pan / tilt head described in Patent Document 1, a slip ring transmission portion formed by a plurality of conductive contact pieces that are in sliding contact with a plurality of conductive rings rotated together with the rotating body, and an optical axis that coincides with the rotation axis of the rotating body A light emitting element that is fixed to one end of the rotating body so as to form a rotating body, rotates with the rotating body, a light signal transmitting unit that transmits a signal by a light receiving element that receives light from the light emitting element, a transmission gear that rotates the camera, In the electric head having two bearings for rotatably holding the rotating body, the slip ring transmission portion is surrounded by the first closed space and the optical signal transmission portion is surrounded by the second closed space. Thus, the transmission gear is provided outside these closed spaces. In particular, in the details of the configuration, the bearing partitions the first and second closed spaces.
Japanese Patent No. 3687453 (FIGS. 2 and 4)

  However, the electric head described in Patent Document 1 has the following problems. That is, the structure of the bearing is difficult to completely cut off the partitioning side and the partitioning side, and the grease scattered from the sliding contact transmission unit by the slip ring and the brush existing in the first closed space is difficult to take. And then enters the second closed space and adheres to the light exit / incident surface of the optical transmission transmission unit, which may reduce the optical transmission efficiency of the optical transmission transmission unit.

  That is, it is necessary to apply grease to the sliding contact portion between the slip ring and the brush in order to maintain stable contact. Also, since the sliding contact part to which grease is applied is structurally provided near the optical transmission transmission part, oil mist due to the oil component of the grease applied to the sliding contact part is scattered, and this scattered oil mist is In some cases, an oil film is formed by adhering to the light incident / incident surface of the transmission unit. Due to the formed oil film, the amount of light emitted from the light emitting surface of the light emitting element or the amount of light incident on the light incident surface of the light receiving element may be reduced, and the light transmission efficiency of the light transmission transmission unit may be reduced.

  In addition, when an oil film is formed on the light incident / incident surface of the light emitting element or the light receiving element, dust easily adheres to the oil film. Furthermore, in addition to dust, deteriorated grease may be scattered and attached from the contact portion. There was a case where the optical transmission efficiency of the optical transmission transmission unit is further reduced due to this deposit.

  Furthermore, it is preferable to enclose grease as a lubricant in the bearing that sandwiches the sliding contact portion, but by doing so, the grease encapsulated in the bearing becomes an oil mist, and similarly the optical transmission of the optical transmission transmission portion. There was a risk of reducing efficiency. Thus, in the conventional closed space structure, the oil mist and dust-proof measures of the optical signal transmission unit were insufficient.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotary joint that prevents a decrease in reliability of optical transmission.

  In order to achieve the above object, the first feature of the rotary joint according to the present invention is that a fixed part, a rotating part rotatable about the axis with respect to the fixed part, and at least one end of the fixed part in the fixed part. It has a hollow rotating body part that is rotatably mounted by a bearing at the center and whose other end is fixed or engaged with the rotating part, and between the fixed part and the rotating part via the rotating body part. The rotary joint is configured to transmit information with the rotating body portion, and the rotating body portion includes a conductive ring provided on the outer peripheral portion of the rotating body portion, and a light provided substantially coaxially with the shaft inside the rotating body portion. A light transmitting means having transparency, and the rotating part includes a first light emitting element or a first light receiving element arranged so as to be close to one end of the light transmitting means, and the fixing part is fixed Provided in sliding contact with the bearing and conductive ring inside the part The conductive brush is fixed and close to the conductive ring housing in which the conductive ring is housed and the other end of the optical transmission means, and is paired with the first light emitting element or the first light receiving element. An optical transmission housing that houses the second light receiving element or the second light emitting element, the second light receiving element or the second light emitting element, and the other end of the optical transmission means, The light receiving element or the second light emitting element and the other end of the light transmitting means do not interfere with the light transmission, and the lubricant applied to the bearing and the conductive ring inside the light transmitting housing. A shielding wall provided between the conductive ring housing and the optical transmission housing is provided so as to shield the intrusion.

  In order to achieve the above object, the second feature of the rotary joint according to the present invention is that the rotating body portion is formed of a light-transmitting member, and the end of the rotating body portion on the rotating portion side is The surface orthogonal to the axis is molded so as to form a mortar-shaped inclined surface in the axial direction from the outer peripheral side of the rotating body portion toward the central portion of the rotating body portion. The optical signal transmission with the end portion further includes a third light receiving element or a third light emitting element fixed at a position where an optical path is provided by light reflection of a mortar-shaped inclined surface, A fourth light-emitting element or a fourth light-receiving element fixed inside the optical transmission housing so as to be paired with the light-receiving element or the third light-emitting element; Between the light emitting surface of the fourth light emitting element or the light receiving surface of the fourth light receiving element. It characterized in that the optical path is further provided with a reflecting member provided so as to establish.

  According to the rotary joint of the present invention, it is possible to prevent a decrease in the reliability of optical transmission.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

<First Embodiment>
In the present embodiment, light transmission is performed by an optical transmission transmission unit that includes a light emitting element, a light receiving element, and an optical transmission member formed of a resin having optical transparency between the light receiving and emitting elements, and a brush and a conductive ring are used. A rotary joint that transmits electric power or an electric signal by sliding contact will be described as an example.

  FIG. 1 is a configuration diagram showing a configuration of a rotary joint according to a first embodiment of the present invention.

  As shown in FIG. 1, the rotary joint 1 according to the first embodiment has a fixed portion 3, a rotating portion 2 that rotates about the axis P with respect to the fixed portion 3, and one end with respect to the fixed portion 3. A hollow rotating body portion 21 that is rotatably attached around the axis P and whose other end is fixed to the rotating portion 2 is provided.

  The fixed part 3 has hollow bearings 4a and 4b as bearings that rotatably hold the rotating body part 21. Then, the rotator 21 is rotated by the power of the direct drive motor 17 having a hollow portion provided around the rotator 21, thereby rotating the rotator 2 together with the rotator 21 with respect to the fixed portion 3. To do.

  The rotating unit 2 may be fixed to the rotor unit (not shown) of the direct drive motor 17 and the rotating body unit 21 and the rotor unit of the direct drive 17 may be engaged.

  In order to smoothly rotate the rotating body 21, the hollow bearings 4a and 4b are filled with grease as a lubricant.

  A slip ring transmission portion 5 is formed on the outer peripheral portion of the rotating body portion 21 and inside the hollow bearings 4a and 4b. Specifically, the slip ring transmission portion 5 includes a plurality (11 in this embodiment) of conductive rings 6 on the outer peripheral portion of the rotating body portion 21 and inside the hollow bearings 4a and 4b. It is fixed via an insulating ring 7.

  A plurality (11 in this embodiment) of brushes 8 are fixed to the insulating base 9 so as to maintain the sliding contact corresponding to the eleven conductive rings 6, respectively. The fixing part 3 is fixed to a conductive ring housing 12 formed so as to accommodate the conductive ring. And each front-end | tip part of the brush 8 is pressed by the conductive ring 6 with the elastic force of each brush 8 itself, and the stability of contact is ensured.

  One end of the rotating part 2 side lead wire 10 is connected to each of the eleven conductive rings 6, and the other end of the rotating part 2 side lead wire 10 passes through the inside of the rotating body part 21, and the rotating part 2. It is pulled out to the side and connected to a drive unit 105 (see FIG. 2 described later) or the like. The eleven brushes 8 are each connected to one end of the fixed portion 3 side lead wire 11, and the other end of the fixed portion 3 side lead wire 11 is drawn out to the fixed portion 3 side to control circuit 109 and It is connected to a power supply circuit 110 (both refer to FIG. 2 described later). In this way, the electrical connection between the drive unit 105 on the rotating unit 2 side and the control circuit 109, the power supply circuit 110, etc. on the fixed unit 3 side, which are respectively connected via the brushes 8 that are in sliding contact with the conductive ring 6. Is established. In order to maintain a good electrical connection, grease is applied to the sliding contact portion between the conductive ring 6 and the brush 8 as a lubricant.

  In addition, a photodiode 16 as a light receiving element is attached to the photodiode substrate 15 on the fixed portion 3 so that the optical axis of the photodiode 16 substantially coincides with the axis P. It is fixed to an optical transmission housing 18 formed so as to accommodate the diode 16.

  A laser diode 13 that is a light emitting element is attached to the laser diode substrate 14 so that the optical axis of the laser diode 13 substantially coincides with the axis P.

  As shown in FIG. 1, the inside of the rotator 21 is a cavity, and a cylindrical light guide having a light transmittance of about several hundred μm to several mm between the laser diode 13 and the photodiode 16. A tube 19 is provided with the center axis of the columnar shape and the axis P substantially coincident with each other.

  The light guide tube 19 is fixed so that one of the light guide tubes 19 (on the rotating unit 2 side) can obtain an optical coupling optimum for the light emitted from the laser diode 13. Further, the distance between the other side of the light guide tube 19 (on the fixed portion 3 side) and the light receiving portion of the photodiode 16 is set to be several mm or less so as not to physically contact the light guide tube 19. The signal light emitted from the other side (the fixed portion 3 side) is incident on the photodiode 16 through this short-distance free space.

  As a result, the signal light emitted from the laser diode 13 and propagated through the light guide tube 19 is received by the photodiode 16 to establish optical transmission.

  Then, the oil mist of grease applied to the sliding contact portion of the conductive ring 6 and the brush 8 scattered by the rotation of the slip ring transmitting portion 5 or the oil mist of grease sealed in the hollow bearing 4 a A shielding wall 20 is provided adjacent to the light transmission housing 18 side of the hollow bearing 4a so as not to adhere to the light incident surface or the light emitting end surface of the light guide tube 19.

  Specifically, an internal space 22 formed by a conductive ring housing 12 that houses a sliding contact portion between the brush 8 and the conductive ring 6, a light emitting end face of the light guide tube 19, and a photodiode 16 that receives an optical signal are provided. The shielding wall 20 is fixed between the conductive ring housing 12 and the optical transmission housing 18 so as to be separated from the internal space 23 formed by the optical transmission housing 18 to be accommodated and close to the hollow bearing 4a.

  This prevents oil mist from entering the internal space 23 and prevents a decrease in the amount of light incident on the light incident surface of the photodiode 16 and a decrease in the amount of light emitted from the light exit surface of the light guide tube 19. it can.

  Although a bearing is also used in the direct drive motor 17, the bearing is sealed in the direct drive motor 17 and has a sufficient distance from the photodiode 16. There is no effect of oil mist splashing from the bearing.

  Next, the configuration of the electric surveillance camera system 100 to which the rotary joint 1 according to the first embodiment is applied will be described.

  FIG. 2 is a configuration diagram illustrating a configuration of the electric surveillance camera system 100 to which the rotary joint 1 according to the first embodiment is applied.

  As shown in FIG. 2, the electric surveillance camera system 100 includes a turning unit 101 and an installation unit 102, and the turning unit 101 and the installation unit 102 are connected by a rotary joint 1. The swivel unit 101 includes a high-definition, for example, SXVGA (1280 × 960 pixels), 30 fps camera 103, a parallel-to-serial conversion unit 104, a drive unit 105, and a tilt motor 106.

  The output of the camera 103 is output as parallel data of 8 bits for each of RGB, and is input to the parallel → serial conversion unit 104. The parallel-to-serial conversion unit 104 converts parallel data into a single piece of serial data. The serial data signal is output to the rotary joint 1 after the 8B-10B conversion. The transmission rate of the 8B-10B converted serial data signal is about 1.1 to 1.5 Gbps. Thereby, the laser diode 13 of the rotary joint 1 outputs the signal light whose intensity is modulated by the serial data. Since the frequency response of the laser diode 13 can easily obtain performance of about several GHz, data transmission of about 1.1 to 1.5 Gbps can be sufficiently performed. Further, since the laser diode 13 is arranged so that the outgoing optical axis substantially coincides with the axis P that is the rotational axis, the signal light emitted from the laser diode 13 is a light guide tube 19 provided at the rotational axis center. Is incident on one end. The signal light incident on the light guide tube 19 propagates toward the other end, and the signal light propagated in the light guide tube 19 is emitted from the other end into the installation portion 102.

  The installation unit 102 includes an O / E conversion unit 107, a serial-to-parallel conversion unit 108, a control circuit 109, a power supply circuit 110, a drive unit 111, a direct drive motor 17, and a network circuit 113.

  The signal light emitted from the light guide tube 19 of the rotary joint 1 is received by the photodiode 16, converted into an electric signal by the O / E conversion unit 107, and then output to the serial → parallel conversion unit 108. The serial-to-parallel converter 108 performs 10B-8B conversion on the received serial electrical signal, demodulates it to the RGB parallel data signal of the camera 103, and outputs it from the network circuit 113 through the video output connector 114. The video output connector 114 is connected to a PC or monitor (not shown) via a cable, and camera image data output via the video output connector 114 is recorded or reproduced.

  Further, a direct drive motor 17 effective for space saving and noise reduction of the drive system is installed as an actuator for rotating the rotating unit 2, and is driven based on a control signal supplied from the driving unit 111. By driving the direct drive motor 17, the rotating unit 2 is rotated about the axis P, and the entire turning unit 101 is rotated accordingly. Since the direct drive motor 17 has a structure that does not require a power transmission component such as a transmission gear, it is not necessary to consider the scattering of grease applied to the power transmission component.

  As described above, when the rotary joint 1 according to the first embodiment is applied to the electric surveillance camera system 100, oil mist or hollow bearings generated from the grease applied to the sliding contact portion between the brush 8 and the conductive ring 6 are obtained. It is possible to prevent a decrease in light transmission efficiency of the light transmission transmission unit due to scattering of oil mist enclosed in 4a, and to realize an electric surveillance camera system that can stably receive a monitoring image.

<Second Embodiment>
FIG. 3 is a configuration diagram showing the configuration of the rotary joint according to the second embodiment of the present invention.

  In the rotary joint 1 which is 1st Embodiment, it was set as the structure provided with the light guide tube 19 formed with the cylindrical light transmissive member. In addition to the configuration of the rotary joint 1 according to the first embodiment, the rotary joint 1a according to the second embodiment further includes an LED light emitting element 24, a reflecting member 25, and an LED light receiving element 28. The reflecting member 25 is made of a member formed of tin plated tin, and has a light reflecting surface 26 that reflects signal light.

  The LED light emitting element 24 uses an LED light emitting diode that is cheaper than a laser diode, and can transmit a control signal of about several tens to 100 Mbps. The LED light emitting element 24 is fixed to the light transmission housing 18, and the control signal light emitted from the LED light emitting element 24 is reflected by the reflecting surface 26 of the reflecting member 25 toward the rotating body portion 21, and the rotating body portion. 21 is incident on the end face 27.

  Further, as shown in FIG. 3, the rotating body portion 21 of the rotary joint 1 a according to the second embodiment is formed of a light-transmitting resin having a hollow cylindrical shape, and the end surface on the rotating portion 2 side is hollow. It is molded so as to form a mortar-shaped inclined surface from the outer peripheral side of the cylindrical shape in the axis P direction toward the center of the light guide tube 19.

  Thereby, the rotator 21 transmits the control signal light of the LED light emitting element 24 incident from one end 27 of the rotator 21 inside, and transmits the transmitted control signal light to the end face on the rotator 2 side. Then, the light is reflected to the outer peripheral side of the hollow cylindrical shape and is incident on the LED light receiving element 28 provided on the rotating unit 2 side.

  Here, the rotator 21 rotates together with the rotator 2 around the axis P as a rotation axis. Also in this case, since the rotator 21 has a hollow cylindrical shape, the positional relationship among the LED light emitting element 24, the reflecting member 25, and the light incident surface of the rotator 21 does not change. Therefore, the rotating body 21 can transmit the control signal light stably to the LED light receiving element 28 that rotates with the rotating body 21 by causing the control signal light to enter while propagating and propagating through the inside.

  Moreover, in the rotary joint 1 which is 1st Embodiment, although a control signal is transmitted from the fixing | fixed part 3 to the rotation part 2 using the sliding contact by the brush 8 and the electrically-conductive ring 6, it is 2nd Embodiment. In the rotary joint 1a, electric power from the fixed portion 3 to the rotating portion 2 may be supplied using sliding contact between the brush 8 and the conductive ring 6.

  Thus, in order to transmit light using the light guide tube 19 as a transmission path of a video signal that requires higher speed optical transmission, and to transmit control signal light that is relatively low in speed, the rotating body 21 By performing optical transmission using the, data transmission can be performed more efficiently.

  The LED light emitting element 24, the reflecting member 25, and the light incident end surfaces of the rotating body 21 are all disposed in an internal space 23 formed by the light transmission housing 18, the substrate 15, and the shielding wall 20. . This reduces the light transmission efficiency of the light transmission transmission portion due to the adhesion of oil mist generated from the grease applied to the sliding contact portion of the brush 8 and the conductive ring 6 or oil mist generated from the grease sealed in the hollow bearing 4a. It is preventing.

  Specifically, the shielding wall 20 is formed so as to partition the internal space 22 formed by the conductive ring housing 12 surrounding the sliding contact portion between the brush 8 and the conductive ring 6 and the internal space 23 formed by the optical transmission housing 18. The oil mist generated from the grease applied to the sliding contact portion between the brush 8 and the conductive ring 6 and the oil mist generated from the grease sealed in the hollow bearing 4a are prevented from entering the internal space 23. be able to.

  This not only prevents a decrease in the amount of incident light from the incident surface of the photodiode 16 or the light incident surface of the light guide tube 19, but also decreases the amount of emitted light from the LED light emitting element 24, decreases the reflection efficiency of the reflector 26, And the fall of the incident light quantity to the one edge part 27 of the rotary body part 21 can be prevented.

  As described above, according to the rotary joint 1a of the second embodiment, high-definition camera video transmission is performed by the light guide tube 19 with respect to the axis P that is one rotation axis, and control signal transmission is performed by the rotating body unit 21. Can be used together to form an asymmetric bidirectional optical transmission line optimal for high-definition camera video transmission.

  In addition, although the cheap tin plate was used for the material of the reflection member 25 of the rotary joint 1a which is 2nd Embodiment, a material is not restricted to tin plate. The reflective surface may be formed of a mirror or resin glossy surface so that the control signal light from the LED light emitting element 24 is reflected.

  FIG. 4 is a configuration diagram showing a configuration of an electric surveillance camera system 100a to which the rotary joint 1a according to the second embodiment is applied.

  As shown in FIG. 4, in addition to the configuration of the electric monitoring camera system 100 to which the rotary joint 1 according to the first embodiment is applied, the electric monitoring camera system 100a further includes a parallel-to-serial conversion unit 115 in the installation unit 102. The turning unit 101 includes a serial-to-parallel conversion unit 116 and a control circuit 117.

  The parallel-to-serial conversion unit 115 converts the control signal output as parallel data from the control circuit 109 into serial data. The control signal converted into serial data is supplied to the rotary joint 1a, and the control signal supplied to the rotary joint 1a is converted into control signal light by the LED light emitting element 24 and emitted.

  The control signal light emitted from the LED light emitting element 24 is incident from one end 27 of the rotator unit 21 formed of a light-transmitting resin, and the incident control signal light is transmitted through the rotator unit 21. The light is emitted from the other end of the rotator 21 and enters the LED light receiving element 28 provided on the rotator 2 side.

  The incident control signal light is converted into an electrical signal in the LED light receiving element 28 and supplied to the serial-to-parallel converter 116. The serial-to-parallel conversion unit 116 performs 10B-8B conversion on the serial electric signal sent thereto and supplies the converted control signal to the control circuit 117. Then, the control circuit 117 controls the camera 103 based on the supplied control signal.

  As described above, by applying the rotary joint 1a according to the second embodiment to the electric surveillance camera system 100a, the oil mist or hollow bearing generated from the grease applied to the sliding contact portion between the brush 8 and the conductive ring 6 An electric surveillance camera system capable of preventing a decrease in light transmission efficiency of the light transmission transmission unit due to scattering of oil mist generated from grease enclosed in 4a, and capable of stably transmitting and receiving monitoring images and control signals is realized. it can.

<Third Embodiment>
FIG. 5 is a configuration diagram showing a configuration of a rotary joint according to the third embodiment of the present invention.

 In the rotary joint 1 according to the first embodiment, the rotating unit 2 includes the laser diode 13 and the fixed unit 3 includes the photodiode 16. However, the fixed unit 3 includes the laser diode 13 and the rotating unit 2 includes It is good also as a structure provided with the photodiode 16. FIG.

 The rotary joint 1b according to the third embodiment has a configuration in which the fixed portion 3 includes a laser diode 13 and the rotating portion 2 includes a photodiode 16.

 As shown in FIG. 5, a laser diode 13 that is a light emitting element is attached to the fixed portion 3 on a laser diode substrate 14 such that the optical axis of the laser diode 13 substantially coincides with the axis P. The substrate 14 is fixed by an optical transmission housing 18.

  A photodiode 16 as a light receiving element is attached to the photodiode substrate 15 in the rotating unit 2 so that the optical axis of the photodiode 16 is substantially coincident with the axis P.

  Further, the connecting portion between the conductive ring housing 12 and the light transmission housing 18 is shielded so as to block the internal space 22 formed by the conductive ring housing 12 and the internal space 23 formed by the light transmission housing 18. 20 is fixed to the optical transmission housing 18 adjacent to the optical transmission housing 18 side of the bearing 4a.

  Specifically, there is an internal space 22 formed by a conductive ring housing 12 surrounding a sliding contact portion between the brush 8 and the conductive ring 6, a light emitting end face of the light guide tube 19, and a photodiode 16 for receiving an optical signal. A shielding wall 20 is formed adjacent to the hollow bearing 4a so as to partition the internal space 23 formed by the optical transmission housing 18.

  This prevents the oil mist generated from the grease applied to the sliding contact portion between the brush 8 and the conductive ring 6 or the oil mist generated from the grease sealed in the hollow bearing 4a from entering the internal space 23, and the laser diode. Accordingly, it is possible to prevent a decrease in the amount of light emitted from the light exit surface 13 and a decrease in the amount of incident light from the light incident surface of the light guide tube 19, thereby preventing a decrease in light transmission efficiency of the light transmission transmission unit.

  Next, the structure of the rotation display system 200 to which the rotary joint 1b which is 3rd Embodiment is applied is demonstrated.

  FIG. 6 is a configuration diagram showing a configuration of a rotation display system 200 to which the rotary joint 1b according to the third embodiment is applied.

  As shown in FIG. 6, the rotation display system 200 includes a display unit 118 in place of the camera 103 as compared with the configuration of the electric monitoring camera system 100 to which the rotary joint 1 according to the first embodiment is applied. . Accordingly, the installation unit 102 includes a parallel-to-serial conversion unit 104, and the turning unit 101 includes a serial-to-parallel conversion unit 108.

  As shown in FIG. 6, in the rotary display system 200 to which the rotary joint 1b according to the third embodiment is applied, for example, SXVGA (1280 × 960 pixels), 30 fps video data is transmitted to the network circuit 113 and the control unit 102. It is supplied to the parallel-to-serial converter 104 via a circuit. The supplied video data is converted into parallel serial data by the parallel-to-serial conversion unit 104. The serial data signal is converted into an optical signal by the O / E conversion unit 107 after 8B-10B conversion, and is output to the rotary joint 1b. The transmission rate of the 8B-10B converted serial data signal is about 1.1 to 1.5 Gbps. Thereby, the laser diode 13 of the rotary joint 1b outputs the signal light whose intensity is modulated by the serial data. Since the frequency response of the laser diode 13 can easily obtain performance of about several GHz, data transmission of about 1.1 to 1.5 Gbps can be sufficiently performed. Since the laser diode 13 is arranged so that the output optical axis substantially coincides with the rotation axis, the signal light is incident on one end of the light guide 19 provided at the center of the rotation axis. The incident signal light propagates in the light guide 19 toward the other end, and is emitted into the turning unit 101 from the other end.

  The swivel unit 101 includes a drive unit 105, a tilt motor 106, a serial → parallel conversion unit 108, and a display unit 118.

  The signal light emitted from the light guide tube 19 of the rotary joint 1b is received by the photodiode 16 and converted into an electric signal. The video signal converted into the electrical signal is output to the serial-to-parallel converter 108. The serial-to-parallel conversion unit 108 performs 10B-8B conversion on the received serial electrical signal, demodulates it into a parallel data signal, and outputs it to the display unit 118. The display unit 118 displays a video based on the video data supplied as a parallel data signal.

  As described above, by applying the rotary joint 1a according to the third embodiment to the rotation display system 200, oil mist or hollow 4a bearing generated from the grease applied to the sliding contact portion between the brush 8 and the conductive ring 6 is achieved. It is possible to prevent a decrease in light transmission efficiency due to scattering with oil mistakes enclosed in the container, and it is possible to realize a rotation display system capable of displaying images stably.

  In the rotary joint according to the first to third embodiments, a lens may be provided on the front surface of the laser diode 13 so that more light can be efficiently incident on the light guide tube 19. Further, a condensing means such as a lens may be provided on the front surface of the photodiode 16 so that the signal light is efficiently collected on the photodiode element.

  In the rotary joints according to the first to third embodiments, the laser diode 13 that emits the signal light on the rotating unit side 2 and the light incident end face of the light guide tube 19 or the photoreceiver that receives the signal light. The space in which the light emitting end faces of the diode 16 and the light guide tube 19 are arranged is not a structure connected to the internal space 22 formed by the conductive ring housing 12 of the fixed portion 3. In addition, since the pan and tilt drive system is directly rotated by the direct drive motor 17 without using a transmission mechanism, there is no part coated with grease like a transmission gear. Therefore, it is not necessary to store this space in a closed space, but a closed structure may be used to prevent dust.

 Moreover, in the rotary joint 1a which is 2nd Embodiment, although the rotation part 2 was equipped with the LED light receiving element 28, and it was set as the structure provided with the LED light emitting element 24 in the fixing | fixed part 3, the fixing | fixed part 3 is equipped with the LED light receiving element 28. The rotating unit 2 may include the LED light emitting element 24.

It is the block diagram which showed the structure of the rotary joint which is 1st Embodiment which concerns on this invention. It is the block diagram which showed the structure of the electric surveillance camera system to which the rotary joint which is 1st Embodiment is applied. It is the block diagram which showed the structure of the rotary joint which is 2nd Embodiment which concerns on this invention. It is the block diagram which showed the structure of the electric surveillance camera system to which the rotary joint which is 2nd Embodiment is applied. It is the block diagram which showed the structure of the rotary joint which is 3rd Embodiment which concerns on this invention. It is the block diagram which showed the structure of the rotation display system to which the rotary joint which is 3rd Embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a, 1b ... Rotary joint 2 ... Rotating part 3 ... Fixed part 4a ... Bearing 4a ... Hollow bearing 4a, 4b ... Hollow bearing 5 ... Slip ring transmission part 6 ... Conductive ring 7 ... Insulating ring 8 ... Brush 9 ... Insulating base DESCRIPTION OF SYMBOLS 12 ... Conductive ring housing 13 ... Laser diode 13 ... LED light emitting element 14 ... Laser diode board | substrate 15 ... Photodiode board | substrate 16 ... Photodiode 17 ... Direct drive motor 18 ... Optical transmission housing 19 ... Light guide tube 20 ... Optical transmission housing 20 ... Shielding wall 21 ... Rotating body 24 ... LED light emitting element (second light emitting element)
25 ... Reflecting member 28 ... LED light receiving element (second light receiving element)
DESCRIPTION OF SYMBOLS 100,100a ... Electric surveillance camera system 101 ... Turning part 102 ... Installation part 103 ... Camera 104, 115 ... Parallel-to-serial conversion part 105 ... Drive part 106 ... Tilt motor 107 ... O / E conversion part 108, 116 ... Serial-to-parallel Conversion unit 109 ... Control circuit 110 ... Power supply circuit 111 ... Drive unit 113 ... Network circuit 114 ... Video output connector 117 ... Control circuit 118 ... Display unit 200 ... Rotation display system

Claims (2)

A fixed part, a rotating part rotatable about an axis with respect to the fixed part, and at least one end thereof is rotatably mounted in the fixed part by a bearing around the axis, and the other end is the rotating part A rotary joint fixed or engaged with the rotary joint, and a rotary joint configured to transmit information between the fixed part and the rotary part via the rotary part. ,
The rotating body part is
A conductive ring provided on the outer periphery of the rotating body;
An optical transmission means having light transparency provided substantially coaxially with the shaft inside the rotating body portion;
The rotating part is
A first light emitting element or a first light receiving element arranged so as to be close to one end of the light transmission means;
The fixing part is
A conductive ring housing in which the bearing and a conductive brush provided so as to be in sliding contact with the conductive ring are fixed inside the fixed portion, and the conductive ring is housed therein;
A second light-receiving element or a second light-emitting element provided close to the other end of the light transmission means and paired with the first light-emitting element or the first light-receiving element;
An optical transmission housing that houses the second light receiving element or the second light emitting element and the other end of the optical transmission means;
The second light receiving element or the second light emitting element and the other end of the light transmission means do not interfere with light transmission, and the bearing and the conductive ring inside the light transmission housing A shielding wall provided between the conductive ring housing and the light transmission housing so as to shield the penetration of the applied lubricant;
A rotary joint with a structure. The rotating body part is
The rotating body portion is formed of a light-transmitting member, and the end of the rotating body portion on the rotating portion side is perpendicular to the axis from the outer peripheral side of the rotating body portion in the axial direction. Molded to form a mortar-shaped inclined surface toward the center of
The rotating part is
A third light receiving element or a third light emitting element that is fixed at a position where an optical path is provided by light reflection of the mortar-shaped inclined surface for optical signal transmission between the end of the rotating body part on the fixed part side Further comprising an element,
The fixing part is
A fourth light emitting element or a fourth light receiving element fixed inside the optical transmission housing so as to be paired with the third light receiving element or the third light emitting element;
A reflecting member provided so that an optical path is established by light reflection between the end of the rotating body portion on the fixed portion side and the light emitting surface of the fourth light emitting element or the light receiving surface of the fourth light receiving element. When,
The rotary joint according to claim 1, further comprising:

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