JP2023062586A - wireless communication system - Google Patents

Abstract

To provide a wireless communication system that can be widely applied independently of an inner structure of a rotary machine while suppressing reduction in electric field intensity.SOLUTION: A motor 50 applied with a wireless communication system performs wireless communication between the interior and the exterior of a metal housing 51 configured by engaging a first housing 51a and a second housing 51b with each other. The motor comprises: a wireless sensor unit 5 attached to the first housing; a first passive relay 60 attached to the second housing and provided between the interior and the exterior of the metal housing; and a second passive relay 80 attached to the first housing to relay an electric wave transmitted from the wireless sensor unit to the first passive relay. A reception antenna 85 of the second passive relay is configured by a conductor provided on an antenna substrate 84a. A transmission antenna 81 of the second passive relay 80 is configured by a conductor provided on an antenna substrate 84b. The antenna substrate 84a and antenna substrate 84b are arranged substantially in parallel with each other and adjacent to each other.SELECTED DRAWING: Figure 12

Description

The present invention relates to wireless communication systems.

Wireless sensor bearings have been proposed that incorporate wireless sensor units that include various sensors such as vibration sensors, acceleration sensors, rotation sensors, temperature sensors, etc., and that output data acquired by the various sensors via wireless communication (see, for example, patent documents 1). As a technology for transmitting the data measured by the wireless sensor unit to the outside of a rotary machine to which such a bearing with a wireless sensor is applied, a non-powered repeater is installed to relay radio waves inside and outside the metal housing of the rotary machine. A communication system has been disclosed (eg, Patent Document 2).

JP 2018-66433 A WO2020/209206

In wireless communication systems using parasitic repeaters, it is necessary to suppress propagation loss of radio waves in order to maintain high field strength. In the prior art described above, the terminals of the parasitic repeater inserted through the metal housing of the rotating machine and the receiving antenna are connected with a coaxial cable, and the receiving antenna of the parasitic repeater faces the transmitting antenna of the wireless sensor unit. By using the near-field electromagnetic coupling between the transmitting antenna of the wireless sensor unit and the receiving antenna of the parasitic repeater, the effect of suppressing the propagation loss of the radio waves emitted from the wireless sensor unit is enhanced. ing. Alternatively, a second parasitic repeater that changes the transmission direction of radio waves and relays them is provided between a first parasitic repeater that relays radio waves inside and outside the metal housing of the rotating machine and the wireless sensor unit. The terminal part of the first parasitic repeater inserted through the metal housing of the machine and the receiving antenna are connected with a coaxial cable, and the receiving antenna of the first parasitic repeater is used for transmission of the second parasitic repeater. The second parasitic repeater is arranged opposite to the antenna and utilizes the near-field electromagnetic coupling effect generated between the transmitting antenna of the second parasitic repeater and the receiving antenna of the first parasitic repeater. It enhances the effect of suppressing the propagation loss of radio waves emitted from the repeater. When applying the wireless communication system of this aspect to a rotary machine such as a motor or a speed reducer, the routing of the coaxial cable inside the metal housing and the placement of the second parasitic repeater are It may be limited by multipath fading phenomena due to structures, reflections, etc.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wireless communication system that can be widely applied regardless of the internal structure of a rotating machine while suppressing a decrease in electric field strength. .

To achieve the above object, a wireless communication system according to one aspect of the present invention provides a wireless communication system for performing wireless communication between the inside and the outside of a metal housing in which a first housing and a second housing are fitted together. In a communication system, a wireless sensor unit attached to the first housing, and a first parasitic relay attached to the second housing and provided between the inside and the outside of the metal housing. and a second parasitic repeater attached to the first housing for relaying radio waves transmitted from the wireless sensor unit to the first parasitic repeater, The receiving antenna of the feeding repeater is composed of a conductor provided on a first substrate, and the transmitting antenna of the second parasitic repeater is composed of a conductor provided on a second substrate different from the first substrate. and the first substrate and the second substrate are arranged substantially parallel and close to each other, and the receiving antenna of the first parasitic repeater is arranged when the first housing and the second housing are fitted together. , on an extension plane of the horizontal plane of the second substrate.

According to the above configuration, it is possible to obtain a wireless communication system that can be widely applied regardless of the internal structure of the rotating machine while suppressing a decrease in electric field strength.

As a preferred aspect of the wireless communication system, it is preferable to include a resin member that holds the first substrate and the second substrate substantially parallel to each other.

As a desirable aspect of the wireless communication system, the transmission antenna of the wireless sensor is composed of a conductor provided on a substrate, and the first substrate is arranged substantially parallel to the substrate provided with the transmission antenna of the wireless sensor unit. preferably.

As a preferred aspect of the wireless communication system, it is preferable that the receiving antenna of the first parasitic repeater and the transmitting antenna of the first parasitic repeater are integrated and attached to the second housing. .

As a preferred aspect of the wireless communication system, the receiving antenna of the first parasitic repeater is connected to the transmitting antenna of the first parasitic repeater with a coaxial cable and attached to the second housing. is preferred.

According to the present invention, it is possible to obtain a wireless communication system that can be widely applied regardless of the internal structure of a rotating machine while suppressing a decrease in electric field intensity.

FIG. 1 is a perspective view of a bearing with wireless sensor. FIG. 2 is an exploded perspective view of the bearing with wireless sensor. FIG. 3 is a cross-sectional view of a portion of the wireless sensor-equipped bearing including a power generating portion and a convex portion. FIG. 4 is a cross-sectional view of a portion of the wireless sensor-equipped bearing including a power generating portion and a recess. FIG. 5 is a cross-sectional view of a portion of the bearing with wireless sensor including the sensor substrate. FIG. 6 is an explanatory diagram for explaining the relationship between the voltage of the electromotive force and the time in the bearing with wireless sensor. FIG. 7 is a plan view of the wireless sensor unit. FIG. 8 is a perspective view of the cover. FIG. 9 is a diagram showing an example of the internal configuration of a motor having a bearing with a wireless sensor. FIG. 10 is a diagram illustrating an application example of a wireless communication system according to a first comparative example. FIG. 11 is a diagram illustrating an application example of a wireless communication system according to a second comparative example. FIG. 12 is a diagram showing a specific example of a motor to which the wireless communication system according to the embodiment is applied. FIG. 13 is a schematic structural diagram of a second parasitic repeater according to the embodiment. 14 is a structural diagram showing a specific example of the first unit and the second unit that constitute the motor shown in FIG. 12. FIG. FIG. 15 is a diagram illustrating an application example of the wireless communication system according to the first modification of the embodiment. FIG. 16 is a diagram illustrating an application example of the wireless communication system according to the second modified example of the embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, it demonstrates in detail, referring drawings for the form (henceforth embodiment) for implementing invention. In addition, the present invention is not limited by the following embodiments. In addition, components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that fall within a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be combined as appropriate.

First, a bearing with a wireless sensor will be described as an example to which the wireless sensor according to the present embodiment is applied.

FIG. 1 is a perspective view of a bearing with wireless sensor. FIG. 2 is an exploded perspective view of the bearing with wireless sensor. FIG. 3 is a cross-sectional view of a portion of the wireless sensor-equipped bearing including a power generating portion and a convex portion. FIG. 4 is a cross-sectional view of a portion of the wireless sensor-equipped bearing including a power generating portion and a recess. FIG. 5 is a cross-sectional view of a portion of the bearing with wireless sensor including the sensor substrate. The wireless sensor-equipped bearing 1 shown in FIG. 1 includes a wireless sensor unit 5, a tone ring 30, and a bearing main body (first bearing) 20, as shown in FIG.

As shown in FIGS. 3 to 5, the bearing body (first bearing) 20 is a rolling bearing having an outer ring 21, an inner ring 22, and rolling elements 23. As shown in FIGS. The outer ring 21 and the inner ring 22 relatively rotate around the rotation axis Ax (see FIG. 1). In the following description, the inner ring 22 is assumed to be a rotating ring.

The cover 10 has an annular top plate 12 and a cylindrical side plate 11 connected around the top plate 12 . The cover 10 is made of a magnetic material such as silicon steel plate, carbon steel (JIS SS400 or S45C), martensitic stainless (JIS SUS420) or ferritic stainless (JIS SUS430).

As shown in FIG. 2 , in the wireless sensor unit 5 , a plurality of power generation sections 3 and a substrate 40 are attached to one surface 12A of the top plate 12 . One surface 12A is a surface facing the bearing main body (first bearing) 20 . The board 40 has a power supply board 41 and a sensor board 42 .

For example, as shown in FIGS. 1 and 2 , the power generation unit 3 is fixed to the top plate 12 by fastening bolts 19</b>A made of a non-magnetic material such as brass to female screw holes drilled in the top plate 12 . Similarly, the power board 41 and the sensor board 42 are fixed to the top plate 12 by fastening bolts 19B made of a non-magnetic material such as brass to female screw holes drilled in the top plate 12 . As shown in FIG. 1 , the bolts 19A and 19B have lengths that do not protrude from the cover 10 when attached to the cover 10 .

The tone ring 30 is provided with convex portions 31 protruding radially outward and concave portions 32 concave radially inward from the convex portions 31 alternately arranged in the circumferential direction. The tone ring 30 has a cylindrical protrusion 33 protruding toward the bearing main body (first bearing) 20 on its inner peripheral side. The tone ring 30 is made of a magnetic material such as silicon steel plate, carbon steel (JIS standard SS400 or S45C), martensitic stainless steel (JIS standard SUS420) or ferritic stainless steel (JIS standard SUS430). .

The power generation section 3 has a permanent magnet 13 , a yoke 14 and a coil 15 . A permanent magnet 13 is fixed so as to be in contact with the top plate 12 . Yoke 14 is fixed so as to be in contact with permanent magnet 13 . The yoke 14 may be magnetically connected to the permanent magnet 13, and may not be directly connected. The yoke 14 is made of a magnetic material such as a silicon steel plate or NiFe alloy. It is desirable that the yoke 14 be made of a material having a magnetic permeability equal to or higher than that of the cover 10 so that the amount of magnetic flux inside the yoke 14 increases. If the yoke 14 is made of a silicon steel plate, the magnetic permeability will be high and the magnetic flux will easily pass through the yoke 14 .

The coil 15 is a so-called magnet wire in which a conducting wire is wound around the yoke 14 . The coils 15 of adjacent power generation units 3 are connected in series, and wires drawn out from the coils 15 of the plurality of power generation units 3 connected in series are connected to the power supply substrate 41 .

As shown in FIG. 3, one end of the side plate 11 is fitted into a groove 21A provided on the outer circumference of the outer ring 21 and fixed. The tubular projection 33 is fitted and fixed in a groove 22A provided on the inner circumference of the inner ring 22 . As a result, as shown in FIGS. 3 and 4, the inner peripheral end face of the yoke 14 and the inner peripheral end face of the top plate 12 are arranged at positions facing the convex portion 31 or the concave portion 32 of the tone ring 30 . Also, the cover 10 and the tone ring 30 can be easily attached to the bearing main body (first bearing) 20 .

The magnetic field of the permanent magnet 13 causes the magnetic flux Mf to pass through the yoke 14 , the convex portion 31 or concave portion 32 of the tone ring 30 , and the top plate 12 of the cover 10 . Therefore, the permanent magnet 13, the yoke 14, the convex portion 31 or concave portion 32 of the tone ring 30, and the top plate 12 of the cover 10 form a magnetic circuit.

Further, as shown in FIG. 5, a magnetic body 311 exhibiting stronger magnetism than the tone ring 30 is attached to a part of the outer peripheral side end face 31IF of the projection 31 . For example, a concave portion corresponding to the shape and size of the magnetic body is provided on the outer peripheral side end surface 31IF of the convex portion 31 . The magnetic body 311 is fitted in this recess. The magnetic body 311 and the outer peripheral side end face 31IF around the magnetic body 311 are flush or substantially flush. The magnetic body 311 is, for example, a hard magnetic permanent magnet. In the tone ring 30, the magnetic body 311 is attached to only one location. The magnetic body 311 comes closest to the angle sensor 443 each time the inner ring 22 makes one relative rotation (360° rotation) with respect to the outer ring 21 . Angle sensor 443 includes, for example, a Hall element.

FIG. 6 is an explanatory diagram for explaining the relationship between the voltage of the electromotive force and the time in the bearing with wireless sensor. Here, the horizontal axis of FIG. 6 is the time T, and the vertical axis is the voltage Vi of the electromotive force. When the outer ring 21 is fixed and the inner ring 22 rotates, the tone ring 30 rotates together with the inner ring 22, and the tone ring 30 and the power generating section 3 rotate relative to each other. For the yoke 14, an air gap from the inner peripheral end surface to the outer peripheral end surface 31IF of the protrusion 31 shown in FIG. 3, an air gap from the inner peripheral end surface to the outer peripheral end surface 32IF of the recessed portion 32 shown in FIG. are alternately replaced.

In this manner, the distance between the yoke 14 of the power generating section 3 and the outer circumference of the tone ring 30 changes periodically due to the protrusions 31 and the recesses 32 on the outer circumference of the tone ring 30 . As a result, the density of the magnetic flux Mf generated in the power generation section 3 changes. When the yoke 14 with the permanent magnet 13 and the tone ring 30 are close to each other, the magnetic flux Mf passing through the permanent magnet 13, the yoke 14, and the tone ring 30 is large, and the yoke 14 and the tone ring 30 are separated. , the magnetic flux Mf passing through the permanent magnet 13, yoke 14, and tone ring 30 is reduced. A voltage change occurs in the coil 15 in which the magnet wire is wound around the yoke 14 according to the density change of the magnetic flux Mf.

That is, when the yoke 14 and the outer peripheral end surface 31IF of the protrusion 31 are closest to each other, the magnetic flux Mf shown in FIG. 3 increases, and the electromotive force voltage V1 shown in FIG. When the yoke 14 and the outer peripheral end surface 32IF of the recess 32 are farthest apart, the magnetic flux Mf shown in FIG.

FIG. 7 is a plan view of the wireless sensor unit. As shown in FIG. 7 , a power supply section 43 is mounted on the power supply board 41 . The power supply unit 43 converts the single-phase AC power supplied from the power generation unit 3 into a DC voltage and supplies the DC voltage to the sensor substrate 42 . A sensor 44 , a control section 45 having a communication circuit, and a transmission antenna 47 are mounted on the sensor substrate 42 . DC power from the power supply unit 43 is supplied to the sensor 44 and the control unit 45 . The sensor 44, the control unit 45, and the transmission antenna 47 may be composed of separate IC (Integrated Circuit) chips, or part or all of them may be composed of one IC chip. Also, the sensor 44 has, for example, an acceleration sensor 441 , a temperature sensor 442 and an angle sensor 443 . The sensor 44 may be one or two of the acceleration sensor 441, the temperature sensor 442, and the angle sensor 443 described above, or may be a sensor that measures other physical quantities.

FIG. 8 is a perspective view of the cover. As shown in FIG. 8, the cover 10 has a through hole 12H. As shown in FIG. 1, the through hole 12H is sealed with a non-magnetic lid 17 made of a non-magnetic material such as resin. As described above, the cover 10 has the transmission antenna 47 on the side of the bearing main body (first bearing) 20 . Here, since the cover 10 has magnetism, it has a function of shielding electromagnetic waves from the transmitting antenna 47 . Therefore, as shown in FIG. 7, the transmitting antenna 47 is arranged so as to overlap the non-magnetic lid 17 in a plan view from the rotation axis Zr direction (the rotation axis Ax direction in FIG. 1) of the bearing body (first bearing) 20. are placed. That is, the non-magnetic lid 17 is provided on the portion of the cover 10 facing the transmitting antenna 47 . Therefore, the electromagnetic wave WV of the transmitting antenna 47 can be radiated in the direction of the rotation axis Zr (Ax) of the bearing main body (first bearing) 20 through the non-magnetic lid 17 and reach the communication section 151 .

Further, as shown in FIG. 8, one surface 12A of the top plate 12 is provided with a plurality of recesses 18 for arranging the power generation unit 3. As shown in FIG. For example, each of the multiple recesses 18 has a first recess 18A for arranging the coil 15 and a second recess 18B for arranging the permanent magnet 13 . When the one surface 12A is used as a reference surface, the first recess 18A is deeper than the second recess 18B.

The control unit 45 has a function of converting various data detected by the sensor 44 from analog data to digital data (for example, A/D conversion) and storing the data. The control unit 45 also has a function of transmitting stored digital data to the outside via the transmission antenna 47 . The control unit 45 operates using DC power supplied from the power supply unit 43 .

Digital data transmitted from the wireless sensor unit 5 is received by the communication section 151 of the host device 150 shown in FIG. Digital data received by the communication unit 151 is processed by the computer 152 . Thus, since the wireless sensor-equipped bearing 1 can wirelessly transmit digital data, it can be miniaturized.

As the wireless sensor according to the present embodiment, in addition to the wireless sensor-equipped bearing 1 described above, there is also a spacer-type wireless sensor module provided near the bearing. A wireless communication system using a wireless sensor such as the above-described bearing 1 with wireless sensor or wireless sensor module will be described below. The following description includes components that are substantially the same as those of the bearing 1 with wireless sensor and host device 150 described with reference to FIGS. 1 to 8 .

In this embodiment, a specific application example of a wireless communication system in a motor equipped with a bearing with a wireless sensor will be described. FIG. 9 is a diagram showing an example of the internal configuration of a motor having a bearing with a wireless sensor. In addition, the same code|symbol is attached|subjected to the same structure part as the structure mentioned above, and the overlapping description is abbreviate|omitted. Moreover, the rotating machine to which the wireless communication system according to the present embodiment is applied is not limited to a motor, and may be, for example, a reduction gear provided with a bearing with a wireless sensor.

The motor 50 has a metal housing 51, a rotor 52, a stator 53, and an output shaft 54 as a basic configuration.

The rotor 52 and output shaft 54 are rotatably held with respect to the metal housing 51 and stator 53 of the motor 50 . The wireless sensor-equipped bearing 1 is provided on the load side of the output shaft 54 to which the rotation control target 100 of the motor 50 is mechanically connected. In the present embodiment, the rotation controlled object 100 (hereinafter also referred to as “load”) of the motor 50 is, for example, a rotating machine such as a pump or a speed reducer.

The wireless sensor unit 5 is provided inside the bearing body (first bearing) 20 on the load side in the direction of the rotation axis Ax. A transmission antenna 47 of the wireless sensor unit 5 is composed of a conductor provided on the sensor substrate 42 . The transmitting antenna 47 is composed of, for example, any one of a pattern antenna, a microstrip patch antenna, and a chip antenna.

The wireless sensor unit 5 of the present disclosure is configured to be covered with the cover 10 provided on the bearing main body (first bearing) 20 as described above. The cover 10 is made of a magnetic material, and the radio waves transmitted from the transmission antenna 47 of the wireless sensor unit 5 pass through the non-magnetic lid 17 that seals the through hole 12H provided in the cover 10 and reaches the bearing body ( The radiation is radiated in the rotation axis Ax direction of the first bearing) 20 . When the bearing 1 with wireless sensor is applied to the motor 50 having the structure shown in FIG. 9, the transmission antenna 47 of the wireless sensor unit 5 is arranged with the maximum radiation direction of radio waves facing inward in the direction of the rotation axis Ax. Therefore, the intensity of radio waves emitted from the transmitting antenna 47 of the wireless sensor unit 5 is maximized in the vertical direction of the sensor substrate 42 . Therefore, when the bearing 1 with wireless sensor is applied to the motor 50 having the configuration shown in FIG. .

A wireless communication system capable of extracting radio waves transmitted from the transmitting antenna 47 of the wireless sensor unit 5 to the outside of the metal housing 51 will be described below.

FIG. 10 is a diagram illustrating an application example of a wireless communication system according to a first comparative example. The same components as those in FIG. 9 are denoted by the same reference numerals, and overlapping descriptions are omitted. In a first comparative example shown in FIG. 10 , the wireless communication system includes a wireless sensor unit 5 and a parasitic repeater 60 .

Each element constituting the parasitic repeater 60 is provided in the first space A on the load side of the output shaft 54 in which the bearing 1 with wireless sensor is provided. Placement is restricted by the structure.

In the example shown in FIG. 10 , the parasitic repeater 60 has a terminal portion 62 inserted through a hole provided in the upper surface of the metal housing 51 . That is, the radiation direction of radio waves from the wireless sensor unit 5 is different from the drilling direction of the hole in the metal casing 51 through which the terminal portion 62 of the parasitic repeater 60 is inserted.

A transmission antenna 61 of the parasitic repeater 60 is provided outside the metal housing 51 . The transmitting antenna 61 can be composed of, for example, a dipole antenna, a monopole antenna, or the like.

The receiving antenna 65 of the parasitic repeater 60 is composed of a conductor provided on an antenna substrate 64 made of resin, for example, and provided inside the metal housing 51 . The receiving antenna 65 can be composed of, for example, a pattern antenna or a microstrip patch antenna, and the receiving sensitivity is maximized in the vertical direction of the antenna substrate 64 . In the first comparative example shown in FIG. 10 , the receiving antenna 65 of the parasitic repeater 60 is arranged at a position where the maximum sensitivity direction substantially coincides with the maximum radiation direction of the transmitting antenna 47 of the wireless sensor unit 5 .

The terminal portion 62 and the antenna substrate 64 are connected by a coaxial cable 63, for example. That is, the transmitting antenna 61 and the receiving antenna 65 are connected via the terminal portion 62 and the coaxial cable 63 . The connection between the antenna substrate 64 and the coaxial cable 63 is, for example, an SMA connector or U.S.A. They are connected by FL connectors. Coaxial cable 63 may be, for example, these SMA connectors or U.S.A. It is a coaxial cable with a diameter of about 1.37 mm, which is suitable for the FL connector.

As shown in FIG. 10 , the receiving antenna 65 of the parasitic repeater 60 is arranged facing the transmitting antenna 47 of the wireless sensor unit 5 . As a result, the maximum radiation direction of the transmitting antenna 47 of the wireless sensor unit 5 and the maximum sensitivity direction of the receiving antenna 65 of the parasitic repeater 60 substantially match.

Further, the reception antenna 65 of the parasitic repeater 60 is arranged at a position where the distance d from the transmission antenna 47 of the wireless sensor unit 5 is λ/2π or less, where λ is the wavelength of the fundamental wave of the radio wave. , the near-field electromagnetic coupling effect generated between the transmitting antenna 47 of the wireless sensor unit 5 and the receiving antenna 65 of the parasitic repeater 60 can be utilized. However, the opposing arrangement of the receiving antenna 65 and the transmitting antenna 47 increases the size in the direction of the rotation axis Ax.

FIG. 11 is a diagram illustrating an application example of a wireless communication system according to a second comparative example. In the second example of the comparative example shown in FIG. 11, the wireless communication system includes a wireless sensor unit 5, a first parasitic repeater 60, and a second parasitic repeater 80. As shown in FIG.

The first parasitic repeater 60 corresponds to the parasitic repeater 60 shown in FIG. In the example shown in FIG. 11, a second parasitic repeater 80 is provided inside the metal housing 51 . The second parasitic repeater 80 changes the radiation direction of the radio waves emitted from the transmission antenna 47 of the wireless sensor unit 5 and transmits the radio waves to the first parasitic repeater 60 .

The receiving antenna 85 of the second parasitic repeater 80 and the transmitting antenna 81 of the second parasitic repeater 80 are composed of conductors provided on an antenna substrate 84 made of resin, for example. In the second example of the comparative example shown in FIG. 11, the receiving antenna 85 and the transmitting antenna 81 are configured by pattern antennas or microstrip patch antennas, for example, and the receiving sensitivity is maximized in the vertical direction of the antenna substrate 84 . In the second parasitic repeater 80, the maximum sensitivity direction of the receiving antenna 85 substantially coincides with the maximum radiation direction of the transmission antenna 47 of the wireless sensor unit 5, and the maximum radiation direction of the transmission antenna 81 is the first parasitic repeater. It is arranged at a position that substantially coincides with the maximum sensitivity direction of the receiving antenna 65 of the repeater 60 . The receiving antenna 85 and the transmitting antenna 81 may be provided on different substrates, and the substrates may be connected to each other by coaxial cables.

As shown in FIG. 11 , the receiving antenna 85 of the second parasitic repeater 80 is arranged facing the transmitting antenna 47 of the wireless sensor unit 5 . As a result, the maximum radiation direction of the transmitting antenna 47 of the wireless sensor unit 5 and the maximum sensitivity direction of the receiving antenna 85 of the second parasitic repeater 80 substantially match.

Also, the transmitting antenna 81 of the second parasitic repeater 80 is arranged to face the receiving antenna 65 of the first parasitic repeater 60 . As a result, the maximum radiation direction of the transmitting antenna 81 of the second parasitic repeater 80 and the maximum sensitivity direction of the receiving antenna 65 of the first parasitic repeater 60 substantially match.

Further, the receiving antenna 85 of the second parasitic repeater 80 is placed at a position where the distance d1 from the transmitting antenna 47 of the wireless sensor unit 5 is λ/2π or less, so that the transmitting antenna 47 of the wireless sensor unit 5 and the receiving antenna 85 of the second parasitic repeater 80, the near-field electromagnetic coupling effect can be utilized.

Further, the distance d2 between the transmitting antenna 81 of the second parasitic repeater 80 and the receiving antenna 65 of the first parasitic repeater 60 is λ/2π, where λ is the wavelength of the fundamental wave of radio waves. By arranging in the following positions, the near-field electromagnetic coupling effect generated between the transmitting antenna 81 of the second parasitic repeater 80 and the receiving antenna 65 of the first parasitic repeater 60 can be utilized. can be done.

As described above, in the first example of the comparative example shown in FIG. 10 and the second example of the comparative example shown in FIG. In the first space A, a transmitting antenna 61 and a receiving antenna 65 of a parasitic repeater (first parasitic repeater) 60 are connected via a terminal portion 62 and a coaxial cable 63 . In such a mode, the routing of the coaxial cable 63 and the arrangement of the second parasitic repeater 80 in the second example of the comparative example shown in FIG. For example, it is limited by ribs provided on the metal housing 51, windings of the stator 53, magnets of the rotor 52, etc.). In particular, in the second example of the comparative example shown in FIG. 11, since the second parasitic repeater 80 has a substantially L-shaped structure, rotary machines to which the wireless communication system can be applied are limited. Further, since the receiving antenna 65 of the parasitic repeater (first parasitic repeater) 60 and the second parasitic repeater 80 are assembled inside the narrow metal housing 51 (first space A), The assembly workability of the motor 50 may deteriorate.

Hereinafter, a wireless communication system according to an embodiment that can expand the application range and improve assembly workability by reducing the size in the direction of the rotation axis Ax will be described.

FIG. 12 is a diagram showing a specific example of a motor to which the wireless communication system according to the embodiment is applied. 11 are assigned the same reference numerals, and overlapping descriptions are omitted.

In the specific example shown in FIG. 12, the metal housing 51 of the motor 50 (rotating machine) is composed of a first housing 51a and a second housing 51b. The wireless communication system according to the embodiment differs from the second comparative example shown in FIG. 11 in the aspect of the second parasitic repeater 80 .

In the configuration shown in FIG. 12, the receiving antenna 85 of the second parasitic repeater 80 is composed of a conductor provided on, for example, a resin antenna substrate 84a (first substrate). Examples of the receiving antenna 85 of the second parasitic repeater 80 include a spiral antenna, a patch antenna, and a microstrip line antenna. The receiving antenna 85 of the second parasitic repeater 80 is not limited to a spiral antenna, a patch antenna, or a microstrip line antenna, and is an antenna having the maximum receiving sensitivity in the vertical direction of the antenna substrate 84a (first substrate). is preferred.

In the configuration shown in FIG. 12, the transmitting antenna 81 of the second parasitic repeater 80 is a conductor provided on an antenna substrate 84b (second substrate) composed of, for example, a Teflon (registered trademark)-based rigid substrate. consists of The transmitting antenna 81 of the second parasitic repeater 80 is exemplified by, for example, a patch antenna, a microstrip line antenna, and the like. The transmitting antenna 81 of the second parasitic repeater 80 is not limited to a patch antenna or a microstripline antenna, and is preferably an omnidirectional antenna in the horizontal plane of the antenna substrate 84b (second substrate).

The antenna substrate 84a (first substrate) provided with the receiving antenna 85 of the second parasitic repeater 80 and the antenna substrate 84b (second substrate) provided with the transmitting antenna 81 of the second parasitic repeater 80 are: , are arranged substantially parallel to each other and close to each other. As a result, the size of the second parasitic repeater 80 in the direction of the rotation axis Ax can be reduced compared to the configuration of the second example of the comparative example shown in FIG. can be expanded.

FIG. 13 is a schematic structural diagram of a second parasitic repeater according to the embodiment. In the example shown in FIG. 13, an antenna substrate 84a (first substrate) provided with the transmitting antenna 81 of the second parasitic repeater 80 and an antenna substrate 84b (having the receiving antenna 85 of the second parasitic repeater 80 provided) The second substrate) is fitted in a resin bracket 87 (resin member) so as to be substantially parallel to each other. It should be noted that the bracket 87 (resin member) may be of a mode that maintains the insulation of the conductors (copper foil patterns) of both the antenna substrate 84a (first substrate) and the antenna substrate 84b (second substrate). As a result, the antenna substrate 84a (first substrate) and the antenna substrate 84b (second substrate) are held in a state of being substantially parallel and close to each other.

The transmitting antenna 81 and the receiving antenna 85 are connected by a transmission line 88 provided on the bracket 87 . In the example shown in FIG. 13, the transmission line 88 may be, for example, a coaxial cable or a waveguide. Further, the transmission line 88 may be configured such that a rod-shaped or plate-shaped conductor is embedded in the bracket 87 and the transmitting antenna 81 and the receiving antenna 85 are connected by the conductor. In this case, it is preferable that the conductor is formed in a gentle curve without providing a bent portion with an acute angle.

14 is a structural diagram showing a specific example of the first unit and the second unit that constitute the motor shown in FIG. 12. FIG. The motor 50 of the aspect shown in FIG. 12 is composed of a first unit 50a and a second unit 50b, as shown in FIG.

The first unit 50a incorporates the wireless sensor equipped bearing 1 in which the output shaft 54 is inserted through the first housing 51a. The second parasitic repeater 80 is attached to the first housing 51a via a resin-made bearing pressing member 55, for example.

A resin-made non-magnetic antenna is attached so that the maximum radiation direction of the transmitting antenna 47 of the wireless sensor unit 5 and the maximum sensitivity direction of the receiving antenna 85 of the second parasitic repeater 80 are aligned (in the direction of arrow b in FIG. 12). The antenna substrate 84a (first substrate) provided with the receiving antenna 85 of the second parasitic repeater 80 is arranged substantially parallel to the substrate provided with the transmitting antenna 47 of the wireless sensor unit 5 across the lid 17. By arranging the receiving antenna 85 of the second parasitic repeater 80 at a position where the distance from the transmitting antenna 47 of the wireless sensor unit 5 is λ/2π or less, the transmitting antenna 47 of the wireless sensor unit 5 and the second The near-field electromagnetic coupling effect generated between the non-feeding repeater 80 and the receiving antenna 85 of the parasitic repeater 80 can be utilized, and the propagation loss of the radio waves radiated from the transmitting antenna 47 of the wireless sensor unit 5 can be suppressed. .

The second unit 50b has a bearing main body (second bearing) 20a attached along a shaft hole 54a provided in the second housing 51b. The first parasitic repeater 60 is inserted through a hole provided in the second housing 51b.

The end of the output shaft 54 incorporated in the first housing 51a is inserted into the shaft hole 54a, and the first housing 51a and the second housing 51b are fitted together in the direction of the rotation axis Ax, thereby rotating the motor 50. Configured.

In the configuration described above, the receiving antenna 65 of the first parasitic repeater 60, as shown in FIG. It is mounted on an extended plane (a plane including the direction of arrow a in FIG. 12) of the horizontal plane of the antenna substrate 84b (second substrate) on which the transmitting antenna 81 of the repeater 80 is provided. As described above, the transmitting antenna 81 of the second parasitic repeater 80 is an omnidirectional antenna in the horizontal plane of the antenna substrate 84b (second substrate), and the horizontal plane of the antenna substrate 84b (second substrate) is extended. By arranging the receiving antenna 65 of the first parasitic repeater 60 on a plane (a plane including the direction of arrow a in FIG. 12), the radio waves radiated from the transmitting antenna 81 of the second parasitic repeater 80 The multipath fading phenomenon caused by reflection in the metal housing 51 is suppressed. As a result, the propagation loss of radio waves radiated from the transmitting antenna 81 of the second parasitic repeater 80 can be suppressed.

In the above-described configuration, the antenna substrate 84a (first substrate) provided with the receiving antenna 85 of the second parasitic repeater 80 (first substrate) and the antenna substrate 84b (second substrate) provided with the transmitting antenna 81 are arranged substantially parallel. By disposing, the second parasitic repeater 80 can be made more compact than the second example of the comparative example shown in FIG.

Furthermore, in the configuration described above, the first parasitic repeater 60 has the receiving antenna 65 and the transmitting antenna 61 integrated via the terminal portion 62, and is inserted through the hole provided in the second housing 51b. In this state, the motor 50 is configured by fitting the first housing 51a and the second housing 51b together. With such a configuration, the assembly workability can be improved more than the first example of the comparative example shown in FIG. 10 and the second example of the comparative example shown in FIG. Moreover, wiring work for the coaxial cable 63 is also unnecessary.

(Modification)
FIG. 15 is a diagram illustrating an application example of the wireless communication system according to the first modification of the embodiment. In FIG. 12, a receiving antenna 65 and a transmitting antenna are arranged on an extended plane (a plane including the direction of arrow a) of the horizontal plane of the antenna substrate 84b (second substrate) on which the transmitting antenna 81 of the second parasitic repeater 80 is provided. 61 are integrated via a terminal portion 62, but as shown in FIG. A hole through which the first parasitic repeater 60 is inserted is provided at a position deviated from the extended plane (plane including the direction of arrow a) of the horizontal plane of the provided antenna substrate 84b (second substrate), and the first parasitic repeater The transmitting antenna 61 and the receiving antenna 65 of the device 60 are connected via the terminal portion 62 and the coaxial cable 63, and the antenna substrate 64 provided with the receiving antenna 65 of the first parasitic repeater 60 is made of resin, for example. may be attached to the second housing 51b via the antenna attachment member 56 of the second housing 51b.

FIG. 16 is a diagram illustrating an application example of the wireless communication system according to the second modified example of the embodiment. FIG. 16 illustrates a perspective view of the first space A on the load side from the direction of the rotation axis Ax.

The receiving antenna 65 of the first parasitic repeater 60 is, as shown in FIGS. 80 on which the transmitting antenna 81 of the first parasitic repeater 60 is mounted. It is not limited by the position of the insertion hole through which the antenna 61 is inserted or the circumferential position of the reception antenna 65 of the first parasitic repeater 60 .

15 and 16, the antenna substrate 64 provided with the receiving antenna 65 of the first parasitic repeater 60 is attached to the second housing 51b via the antenna attachment member 56. , the first housing 51a and the second housing 51b are fitted together to form the motor 50. As shown in FIG. With such a configuration, similar to the wireless communication system according to the embodiment shown in FIGS. can be improved. 10 and 11, since the antenna substrate 64 and the receiving antenna 65 are present on the insertion path of the rotor 52, the assembly method shown in FIG. 14 cannot be adopted. Therefore, although the rotor 52 can only be inserted from the right side, the manner of connection with the rotation control target 100 needs to be devised.

With the configurations of the above-described embodiments and modifications, it is possible to obtain a wireless communication system that can be widely applied regardless of the internal structure of a rotating machine while suppressing a decrease in electric field intensity.

In the present disclosure, a mode in which the wireless communication system is provided in the first space A on the load side of the output shaft 54 in which the wireless sensor equipped bearing 1 inside the metal housing 51 is provided has been described. The bearing main body (bearing 20a) may be a bearing with a wireless sensor, and a wireless communication system may be provided in the second space B, or a wireless communication system may be provided in each of the first space A and the second space B. It may be a mode.

Also, the diagrams used above are conceptual diagrams for qualitatively explaining the present disclosure, and are not limited to these. In addition, although the above-described embodiment is an example of the preferred implementation of the present disclosure, it is not limited to this, and various modifications can be implemented without departing from the gist of the present disclosure.

Reference Signs List 1 bearing with wireless sensor 5 wireless sensor unit 10 cover 17 nonmagnetic lid 20 bearing body (first bearing)
20a bearing body (second bearing)
21 outer ring 22 inner ring 40 substrate 41 power supply substrate 42 sensor substrate 43 power supply section 44 sensor 45 control section 47 transmission antenna (wireless sensor unit)
50 motor (rotating machine)
50a First unit 50b Second unit 51 Metal housing 51a First housing 51b Second housing 52 Rotor 53 Stator 54 Output shaft 54a Shaft hole 55 Bearing pressing member 56 Antenna mounting member 60 Parasitic repeater (first non-feeding power supply repeater)
61 transmitting antenna (parasitic repeater, first parasitic repeater)
62 terminal portion 63 coaxial cable 64 antenna substrate 65 receiving antenna (parasitic repeater, first parasitic repeater)
80 second parasitic repeater 81 transmitting antenna (second parasitic repeater)
84a, 84b antenna substrate 85 receiving antenna (second parasitic repeater)
87 bracket (resin member)
88 transmission path 100 rotation control object 150 host device 151 communication unit 152 computer 441 acceleration sensor 442 temperature sensor 443 angle sensor A first space B second space Ax rotation axis

Claims (5)

A wireless communication system for performing wireless communication between the inside and the outside of a metal housing in which a first housing and a second housing are fitted together,
a wireless sensor unit attached to the first housing;
a first parasitic repeater attached to the second housing and provided between the inside and the outside of the metal housing;
a second parasitic repeater attached to the first housing for relaying radio waves transmitted from the wireless sensor unit to the first parasitic repeater;
with
the receiving antenna of the second parasitic repeater is composed of a conductor provided on the first substrate,
the transmitting antenna of the second parasitic repeater is composed of a conductor provided on a second substrate different from the first substrate,
the first substrate and the second substrate are arranged close to each other in a substantially parallel manner;
A receiving antenna of the first parasitic repeater is arranged on an extension plane of a horizontal plane of the second substrate when the first housing and the second housing are fitted together. The wireless communication system according to claim 1, further comprising a resin member that holds the first substrate and the second substrate substantially parallel. The transmitting antenna of the wireless sensor unit is composed of a conductor provided on a substrate,
3. The wireless communication system according to claim 1, wherein the first substrate is arranged substantially parallel to the substrate provided with the transmitting antenna of the wireless sensor unit. 4. The receiving antenna of the first parasitic repeater and the transmitting antenna of the first parasitic repeater are integrated and attached to the second housing. A wireless communication system as described. 4. The receiving antenna of the first parasitic repeater is connected to the transmitting antenna of the first parasitic repeater with a coaxial cable and attached to the second housing. A wireless communication system according to any one of the preceding paragraphs.

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