Wireless sensing structure for cylinder device

Abstract

[Problem] To provide a wireless sensing structure that allows radio waves to easily spread from a wireless transceiver. [Means for Solving the Problem] A wireless sensing structure with a cylinder device 40 having an independent power generation device 1 is disclosed. The independent power generation device 1 generates electricity in a metal housing 2 in response to changes in the position of a piston and transmits it as an electrical signal. The recess 66 on the bottom surface of the resin cover 62 and the U-shaped groove 63 on the surface are connected by a through hole 65 provided at the starting end of the U-shaped groove. The wireless substrate 70 is mounted in the recess 66, and the antenna 71 is inserted through the through hole 65 and folded and fixed sequentially along the U-shaped groove 63. A portion of the upper side of the housing 2 is cut into a shape similar to the outer shape of the cover 62, and a recess 2d is provided for the cover 62 to be inserted into. The cover 62 closes the recess 2d.

Description

Technical Field

[0001] The present invention relates to a wireless sensing structure for use in a cylinder device of an independent power generation device, which generates electricity to produce electrical signals by means of mechanical movement within a metal housing. Prior Technology

[0002] Regarding devices that generate current and transmit mechanical changes as electrical signals to the outside without a power source or external electrical wiring, independent power generation devices illustrated in Patent Documents 1 to 3 are known. As shown in any of these patent documents, a very small wireless transceiver is arranged near the independent power generation device. A series of actions are performed, including supplying the power generated by the mechanical changes to the wireless transceiver, and the wireless transceiver wirelessly transmitting the generation of the mechanical changes.

[0003] Furthermore, this applicant has proposed, based on Japanese Patent Application No. 2023-166280 and Japanese Patent Application No. 2024-3414, an independent power generation device that directly generates electricity using linear motion from an external source, and has shown examples of applying the independent power generation device to cylinder devices such as clamping devices or pressure detectors. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-516802 [Patent Document 2] Japanese Patent Publication No. 2022-552337 [Patent Document 3] Japanese Patent Application Publication No. 2018-153094 Summary of the Invention

[0005] (The problem that the invention aims to solve) Radio waves can be blocked by metal, but the outer casing of these cylinder devices is itself made of metal. It is desirable to realize a wireless sensing structure in which an independent power generation device generates an electrical signal when detecting the piston movement within the metal casing of the cylinder device, and emits it wirelessly to the outside, so that the weak radio waves are not blocked by the metal casing as much as possible.

[0006] The purpose of this invention is to provide a wireless sensing structure in which the electrical signal of an independent power generation device that detects mechanical changes in the metal housing of a cylinder device is wirelessly radiated to the outside, making it easy for the radio waves to spread from the wireless transceiver. (Methods used to solve problems)

[0007] According to the present invention, a wireless sensing structure for a cylinder assembly is provided, comprising an independent power generation device that generates electricity within a metal housing in response to changes in the position of the piston portion, and transmits this electricity as an electrical signal. The characteristic of this wireless sensing structure for the cylinder assembly with an independent power generation device is that… have: A wireless substrate, which is formed by erecting an antenna from a substrate on which a wireless transmission LSI is mounted; and The resin cover has a recessed portion on the bottom surface and a U-shaped groove on the surface surface connected by a through hole at the beginning of the U-shaped groove. The aforementioned wireless substrate is mounted in the aforementioned recessed portion, and the aforementioned antenna is inserted through the aforementioned through hole. The cover is then folded and fixed sequentially along the aforementioned U-shaped groove. A portion of the upper side of the aforementioned outer shell is cut out to resemble the shape of the aforementioned cover, so as to provide a recess for the aforementioned cover to be inserted. The aforementioned wireless module covers the recess, thereby sealing the recess. (Effects of the invention)

[0008] According to the wireless sensing structure of the present invention, a shape similar to the shape of a wireless module is cut out on a portion of the upper side of the outer shell to provide a recess for the cover to be inserted. The wireless module covers the recess, thereby making the metal of the outer shell in the horizontal direction, which would be an obstacle to the radio waves emitted from the antenna folded in the U-shaped groove, disappear, and the radio waves become easier to diffuse. Simple Explanation of the Diagram

[0009] Figure 1 is a diagram illustrating an independent power generation unit. Figure 2 is a diagram illustrating the components of an independent power generation unit. Figure 3 is a diagram illustrating the components of an independent power generation unit. Figure 4 illustrates the operation of an independent power generation unit. Figure 5 is a perspective view of the cylinder block assembly. Figure 6 illustrates the unlocked state. Figure 7 illustrates the conditions along the way. Figure 8 illustrates the locked state. Figure 9 illustrates the state of the wireless module being removed. Figure 10 illustrates the structure of the wireless module. Implementation

[0010] First, the independent power generation device will be explained. Regarding the independent power generation device, the independent power generation device disclosed in Patent Documents 1-3, or the independent power generation device proposed under Japanese Patent Application No. 2023-166280 and Japanese Patent Application No. 2024-3414, may be applied.

[0011] Here, we will explain the independent power generation device proposed by Japanese Patent Application Nos. 2023-166280 and 2024-3414, which were not well known at the time of application in this case. In Figure 1A, the independent power generation device 1 includes: a magnet unit 13 fixed to the outer casing 2 by bolts 23; and a coil unit 12 movable toward the iron core axis c1 by a detection part 11 made of a sphere. The magnet unit 13 includes: a permanent magnet 14, a magnetic flux passage 15 above a soft magnetic body, and a magnetic flux passage 16 below a soft magnetic body. Magnetic flux passages of soft magnetic body are respectively provided for the upper and lower magnetic poles of the permanent magnet 14. The two magnetic flux passages 15 and 16 are arranged to sandwich the permanent magnet 14, forming a U-shape in side view, with one magnetic flux passage 15 on the inside and the other magnetic flux passage 16 on the outside, overlapping each other with a gap. Then, the two ends of the magnetic flux passage 15 become magnetic pole pieces 15a and 15b, and the two ends of the magnetic flux passage 16 become magnetic pole pieces 16a and 16b.

[0012] The coil unit 12 comprises: an iron core 17, a coil 19 wound around the outer periphery of the iron core 17 by a spacer frame 19a, and contact terminals 21 and 22 arranged in a ring around the coil 19. Magnetic pole pieces 15a and 16a form a pair facing each other on the front side of the coil 19, and magnetic pole pieces 15b and 16b form a pair facing each other on the rear side of the coil 19. The iron core 17 has a front end 17a on its front side (right side in the figure) along its core axis c1, an iron core body 17b in the center, and a rear end 17c on its rear side (left side in the figure), forming a cylindrical shape with the core axis c1 aligning with the radial direction of the center line C. Hereinafter, the right side of the core axis c1 in the figure will be referred to as the front side, and the left side as the rear side. The length of the iron core 17 along its core axis c1 is mostly the iron core body 17b, with the coil 19 wound around the outer periphery of the iron core body 17b. Not explicitly shown in the diagram, the wire frame 19a is then fixed to the magnetic flux path 15. The core body 17b is not fixed to the coil 19, and the core body 17b can move along the core axis c1 via the hollow portion of the wire frame 19a, which serves as the center of the coil 19.

[0013] The core body 17b is a soft magnetic material. The front end 17a and the rear end 17c can be soft magnetic materials or non-magnetic materials. However, in the case of soft magnetic materials, a gap must be provided to avoid magnetic short circuits with the magnetic flux paths 15 and 16 above and below.

[0014] The core body 17b and its front end portion 17a, and the core body 17b and its rear end portion 17c, are provided with protrusions a and recesses b, respectively, to fit together. Furthermore, the outer peripheral surfaces between the core body 17b and its front end portion 17a, and between the core body 17b and its rear end portion 17c, are provided with sliding surfaces 17d and 17e, which have a smaller diameter at a distance d than the other outer peripheral surfaces. Contact terminals 21 and 22 are softly magnetic and are respectively fitted onto the outer periphery of the sliding surfaces 17d and 17e. The contact terminals 21 and 22 can move freely along the core axis c1 at a distance d on the sliding surfaces 17d and 17e. The larger diameter portion of the core body 17b and the front end portion 17a and the rear end portion 17c restrict the movement of the contact terminals 21 and 22 beyond the distance d. The two contact terminals 21 and 22 are always in contact with the corresponding sliding surfaces 17d and 17e, allowing magnetic flux to pass through without magnetic gap between the iron core body 17b and the contact terminals 21 and 22.

[0015] The front end 17a of the iron core 17 abuts against the detection part 11. When the radial movement of the center line C is transmitted from the detection part 11 to the iron core 17, the rear end 17c of the iron core 17 moves relative to the magnet unit 13 along the iron core axis c1.

[0016] Figure 2 shows the coil unit 12 and contact terminals 21 and 22 removed, with detailed explanations of their contents. In the figure, the coil 19 (and the wire frame 19a) is indicated by dashed lines. If the front end 17a and rear end 17c of the core 17 are removed from the core body 17b, the contact terminals 21 and 22 can be removed from the sliding surfaces 17d and 17e. The front end 17a has: an input terminal p that abuts against the detection part 11; a first base q with a larger diameter than the sliding surface 17d; and a recess b that engages with the protrusion a of the core body 17b. The rear end 17c has: a base r that abuts against the elastic body 18; a second base s with a larger diameter than the sliding surface 17e; and a recess b that engages with the protrusion a of the core body 17b (Figure 2). The contact terminals 21 and 22 are cylindrical with a height h, which is shorter than the distance d. Each contact terminal 21 and 22 has a contact surface 21a, 21b and a contact surface 22a, 22b that are perpendicular to the iron core axis c1 on the back of the device.

[0017] Figure 3 shows the relationship between the magnet unit 13 and the iron core 17. The magnet unit 13 is fixed to the outer casing 2 by bolts 23, with the permanent magnet 14 sandwiched between the upper and lower magnetic flux passages 15 and 16. The upper and lower magnetic flux passages 15 and 16 are made by bending sheet metal into a U-shape. The ends of the upper and lower magnetic flux passages 15 and 16, i.e., the magnetic pole pieces 15a, 15b, 16a, and 16b, are spaced apart from the iron core body 17b, the front end 17a, and the rear end 17c. This is to prevent contact and the formation of magnetic flux passages when the iron core body 17b, the front end 17a, and the rear end 17c are moved by the detection unit 11 or the elastic body 18, before, during, or after movement.

[0018] The magnetic pole pieces 15a and 16b of the upper and lower magnetic flux paths 15 and 16 expose the magnetic poles of the permanent magnet 14. The magnetic pole pieces 15a and 15b of the upper magnetic flux path 15 and the magnetic pole pieces 16a and 16b of the lower magnetic flux path are arranged in parallel with a gap t between them. The contact surfaces 21b and 21a of the back of the contact terminal 21 can contact the magnetic pole pieces 15a and 16a respectively. The contact surfaces 22a and 22b of the back of the contact terminal 22 can contact the magnetic pole pieces 15b and 16b respectively. Furthermore, the magnetic pole pieces 15a, 15b, 16a, and 16b are provided with arc-shaped cutouts x to increase the contact area with the contact terminals 21 and 22. When the contact terminals 21 and 22 slide on the sliding surfaces 17d and 17e, they are prevented from sliding by abutting against the magnetic pole pieces 15a, 15b, 16a and 16b. Therefore, the movable range of the contact terminals 21 and 22 is the range of the interval t.

[0019] Figure 4 shows the operation of the independent power generation device 1. The rear end 17c of the iron core 17 of the independent power generation device 1 abuts against an elastic body 18, which acts as a compression spring and is housed in a spring chamber 24. The elastic body 18 accumulates elasticity by moving to the rear side of the iron core 17 along the iron core axis c1, and the stored elasticity is used as a force to push the iron core 17 forward. The mechanism for pushing the iron core 17 forward is not limited to the elastic body 18; a mechanism that supplies hydraulic oil or compressed air to the actuation chamber, as described in the first embodiment below, can also be used to push it forward by that pressure. In Figure 4A, the magnetic pole piece 15b on the rear side of the upper magnetic flux passage 15, the contact terminal 22, the iron core body 17b, the contact terminal 21, and the magnetic pole piece 16a on the front side of the lower magnetic flux passage 16 form a magnetic circuit φ1 by creating a magnetic short circuit. The magnetic circuit φ1 is a path that completes one revolution without omission.

[0020] Figure 4B shows the position of the core 17 as it moves to the rear side in the axial direction c1. Contact terminals 21 and 22 are pushed to the front end 17a and the large-diameter portion of the core body 17b, respectively. The rear pole piece 15b of the upper magnetic flux passage 15 begins to separate from the contact terminals 22 and 21, and the front pole piece 16a of the lower magnetic flux passage 16, creating a gap g. Then, the moving speed v1 of the core 17 and contact terminals 21 and 22 up to this point is the moving speed of the detection unit 11. The magnetic force between the rear pole piece 15b of the upper magnetic flux passage 15 and the contact terminal 22, and the magnetic force between the contact terminal 21 and the front pole piece 16a of the lower magnetic flux passage 16, weakens.

[0021] In Figure 4C, at the moment when the magnetic force between the magnetic pole piece 16b on the rear side of the lower magnetic flux passage 15 and the contact terminal 22, and the magnetic force between the contact terminal 21 and the magnetic pole piece 15a on the front side of the upper magnetic flux passage 15, become dominant, the contact terminals 21 and 22 disengage from the state of moving speed v1 and are accelerated on the sliding surfaces 17d and 17e, respectively, and collide with the magnetic pole pieces 15a and 16b. Figures 4B and 4C show the state before and after the iron core 17 hardly moves, while the contact terminals 21 and 22 rapidly accelerate and move.

[0022] In Figure 4C, it is clear that the rear ends of sliding surfaces 17d and 17e are designed with a distance d such that they move to the position of the magnetic pole piece 16b on the rear side of the lower magnetic flux path 16 and the position of the magnetic pole piece 15a on the front side of the upper magnetic flux path 15, or beyond these positions. In this state, the magnetic pole piece 15a on the front side of the upper magnetic flux path 15, the contact terminal 21, the iron core body 17b, the contact terminal 22, and the magnetic pole piece 16b on the rear side of the lower magnetic flux path 16 form a magnetic circuit φ2. Magnetic circuit φ2 is also a path that completes one full rotation without omission. Focusing on the iron core body 17b, the direction of the magnetic flux through the iron core body 17b is opposite in magnetic circuits φ1 and φ2. Because the change in magnetic flux is large when switching instantaneously from magnetic circuit φ1 to magnetic circuit φ2.

[0023] Figure 5 shows a perspective view of a cylinder assembly 40, which is a cylinder assembly equipped with an independent power generation device 1. The cylinder assembly 40 includes: a metal housing 2; a shaft member 5 protruding from the housing 2 and moving vertically; and a linkage clamping mechanism 30 formed by connecting rods 30a and 30b at the front end of the shaft member 5. The housing 2 is formed by integrating a lower cylindrical portion B with a cuboid upper portion T. The lower portion B is supplied with hydraulic oil or compressed air to allow the shaft member 5 to move vertically. Furthermore, the upper portion T is where the wireless module 61 and the independent power generation device 1 are located. The cylinder assembly 40 actuates the independent power generation device 1 when the shaft member 5 is lowered.

[0024] Figure 6 shows a cross-section of the cylinder assembly 40 equipped with an independent power generation device 1. The shaft member 5 has: a shaft body 5a formed sequentially from the top, and a piston portion 5b having a larger diameter than the shaft body 5a. A step portion 5d is provided along the length of the shaft body 5a, with the diameter of the shaft body 5a above the step portion 5d being larger than that below.

[0025] The cylinder assembly 40 supplies hydraulic oil or compressed air to the cylinder bore 3, which is perforated in the outer casing 2, causing the piston 5b to move up and down. The cylinder bore 3 is formed in the top portion 2a, the bottom portion 2b, the main body wall 2c extending in the vertical direction, and the space inside the main body wall 2c. When hydraulic oil or compressed air is supplied to the chamber 3a, which is higher than the piston 5b, the piston 5b descends; when hydraulic oil or compressed air is supplied to the lower chamber 3b, the piston 5b rises.

[0026] The cylindrical hole 4 formed in the top portion 2a of the outer casing 2 surrounds the shaft body 5a, and a part of the shaft member 5 extends through the top portion 2a and out of the outer casing 2. In the figure, ST indicates the range of the stroke of the shaft member 5. This range indicates the vertical movement range of the shaft member 5 at the position marked with "*" in the figure.

[0027] A sleeve 51 is fitted around the outer periphery of the shaft body 5a above the stepped portion 5d. The sleeve 51 is surrounded by a cylindrical hole 4. The lower end 51a of the sleeve 51 is tapered and engages with the stepped portion 5d. The range of movement of the upper end 51b of the sleeve 51 is limited by the top portion 2a of the outer casing 2. That is, even if the shaft body 5a rises, if the upper end 51b of the sleeve 51 abuts against the top portion 2a of the outer casing 2, the sleeve 51 cannot rise further, only the shaft body 5a will rise.

[0028] A displacement portion 53 is provided on the outer periphery of the sleeve 51 at its height. An opening 9 is provided within the range of movement of the displacement portion 53. A probe portion 11, forming a sphere, is embedded in the opening 9 and protrudes out. The probe portion 11 within the opening 9 detects the displacement portion 53 and protrudes from the opening 9. The opening 9 and the displacement portion 53 face each other, and the probe portion 11 overlaps the displacement portion 53, thereby converting the vertical movement of the shaft body 5a into a movement perpendicular to the center line C (the direction of c1, the radial direction of the center line C). The sleeve 51 is biased upward by an elastic body 55 with a fixed end 54 provided on the side of the outer casing 2 as its base.

[0029] The movement of the detection unit 11 is transmitted to the front end 17a of the iron core 17 of the independent power generation device 1. The independent power generation device 1 converts the kinetic energy of the detection unit 11 into electrical energy and supplies power to the wireless module 61 to drive it. The wireless module 61 transmits a signal indicating that it has crossed over wirelessly.

[0030] Furthermore, the rear end 17c of the iron core 17 of the independent power generation device 1 abuts against the elastic body 18, which acts as a compression spring, on the rear side. The elastic body 18 is housed in the spring chamber 24, and elasticity is accumulated in the spring chamber 24 by the iron core 17 moving axially c1 towards the iron core. The elasticity accumulated in the elastic body is used as a force to push the iron core forward when the shaft body 5a descends and the detection part 11 descends from the displacement part 8.

[0031] In Figure 7, the piston part 5b of the cylinder assembly 40 is lowered, and the connecting rod clamping mechanism 30 unlocks the workpiece W. The step part 5d of the shaft body 5a is shown pressing down the sleeve 51, and the detection part 11 is disengaged from the concave displacement part 43.

[0032] Figure 8 shows the cylinder device 40 in the state of sensing initiated by the independent power generation device 1 during the transition from the unlocked state to the locked state. The sleeve 51 is pushed upward by the elastic body 32, and the detection part 11 is about to fall onto the displacement part 53. When the detection part 11 and the displacement part 53 overlap, the independent power generation device 1 can activate the wireless module 61 to notify the outside via a wireless signal.

[0033] Figure 8 shows the cylinder block device 40 in the locked state. This is the state where the sleeve 51 cannot rise, only the shaft body 5a rises. The detection unit 11 is positioned at the displacement unit 53. Therefore, the range in which the sleeve 51 engages with the step portion 5d and descends in conjunction is the lower first range ex11 of the range ST during the stroke of the shaft member 5. This range corresponds to the distance ex1 between the upper end 51b of the sleeve 51 and the canopy portion 2a in Figure 7.

[0034] According to the cylinder assembly 40, the detection part 11 inside the opening 9 overlaps with the displacement part 53, thereby converting the up-and-down movement of the shaft body 5a into a movement perpendicular to the center line C (c1 direction, the radial direction of the center line C). Therefore, when the piston part 5b is in the downward position, the independent power generation device 1 can activate the wireless module 61 to notify the outside via wireless signal.

[0035] Figure 9 shows the state with the wireless module 61 removed from the housing 2. Here, in top view, the long side direction of the upper part T is defined as the x-direction (the same direction as c1), and the short side direction is defined as the y-direction. The x-direction is the long side direction of the upper part T because the independent power generation device 1 is arranged in the c1 direction of the shaft member 5 inside the housing 2.

[0036] The outer casing 2 has a recess 2d for embedding the wireless module 61. The recess 2d is formed by cutting out the entire upper y-direction side of the rectangular upper part T of the outer casing 2 and a portion of the connected x-direction side. The position of the recess 2d corresponds to the position directly above the independent power generation device 1. Furthermore, the recess 2d is similar in shape to the wireless module 61, and the wireless module 61 covers the recess 2d from the outer casing 2, thereby closing the recess 2d. The wireless module 61 is fixed by bolts 60.

[0037] Figure 10 shows a detailed diagram of the wireless module 61. The wireless module 61 includes: a cover 62 made of a resin such as polyphenylene sulfide or polyoxymethylene that does not easily block radio waves; and a wireless substrate 70 consisting of a wireless transmission LSI (not shown) and an antenna 71. Since the cover 62 defines the shape of the wireless module 61, the recess 2d is similar in shape to the cover 62. The wireless module 61 is covered by a gasket 67 that prevents dust and dirt from entering the recess 2d of the outer casing 2.

[0038] Figures 10A-D show the cover 62, with Figure 10A being a top view, Figure 10B a front view, Figure 10C a cross-sectional view along Y1-Y1, and Figure 10D a bottom view. Figures 10E and 10F show the top view and cross-sectional view along Y3-Y3 of the pad 67. Figure 10G shows the side view and top view of the wireless substrate 70.

[0039] In Figure 10I, the wireless substrate 70 is mounted in the recess 66 on the bottom surface of the cover 62. In Figure 10J, the surface of the cover 62 is provided with X-direction grooves 63a, Y-direction grooves 63b, and X-direction grooves 63c, which are continuously arranged in a U-shape. The through hole 65 is connected to the recess 62d at the starting end of the U-shaped groove 63, and the antenna 71 in the recess 66 is inserted through the through hole 65 and extends out of the U-shaped groove 63.

[0040] Antenna 71 is a quarter-wavelength antenna. Antenna 71 is fixed by folding sequentially along the x-direction groove 63a, y-direction groove 63b, and x-direction groove 63c through the through-hole 65. However, if the folding is too small, interference may occur between the folded parts. Therefore, the y-direction groove 63b separates the x-direction grooves 63a and 63c. Furthermore, a cutout similar in shape to the wireless module 61 is formed on a portion of the upper side of the housing 2, providing a recess 2d for the cover 62 to be inserted. The wireless module 61 covers the recess 2d, thereby preventing the metal housing 2 from obstructing the horizontal direction of the antenna 71 portion in the y-direction groove 63b when viewed from above. Additionally, the recess 2d also cuts off a portion of the housing 2 in the x-direction grooves 63a and 63c, thus reducing its obstruction of radio waves.

[0041] Furthermore, the antenna 71 is fixed to the resin cover 62 along its entire length, so it is not easily subjected to mechanical impacts from the outside in the environment where the cylinder device 40 is installed.

[0042] 1: Independent power generation unit 2: Outer shell 2a: Ceiling section 2b: Bottom 2c: Main wall 2d: Depression 3: Cylinder block bore 4: Cylinder hole 5: Shaft components 5a: Shaft body 5b: Piston section 5d: Step difference part 8: Displacement section 9: Opening 11: Detection Department 12: Coil Unit 13: Magnet Unit 14:Permanent magnet 15, 16: Magnetic flux pathways 15a, 15b, 16a, 16b: Magnetic pole pieces 17: Iron core 17a: Front end 17b: Core body 17c: Rear end 17d, 17e: Sliding surfaces 18: Elastomers 19: Coil 19a: Wireframe 21, 22: Contact terminals 21a, 21b: Abutment surfaces 22a, 22b: Abutment surfaces 23: Bolt 24: Spring Chamber 30: Linkage clamping mechanism 30a, 30b: Connecting rod 32: Elastomer 40: Cylinder block assembly 43: Displacement section 51: Sleeve 51a: Lower end 51b: Upper end 53: Displacement section 54: Fixed end 55: Elastomer 60: Bolt 61: Wireless Module 62: Cover 62d: concave part 63:ㄈ-shaped groove 65: Through hole 66: concave part 67: Padding 70: Wireless board 71: Antenna

Claims

1. A wireless sensing structure for a cylinder device, comprising an independent power generation device that generates electricity in response to changes in the position of a piston within a metal housing and transmits it as an electrical signal. The wireless sensing structure for the cylinder device is characterized by comprising: a wireless substrate from which an antenna is mounted on a substrate on which a wireless transmission LSI is mounted; and a resin cover, wherein a recess on the bottom surface and a U-shaped groove on the surface surface are connected by a through hole at the beginning of the U-shaped groove, the wireless substrate is mounted in the recess, the antenna is inserted through the through hole, and the cover is folded and fixed sequentially along the U-shaped groove; a shape similar to the outer shape of the cover is cut out on a portion of the upper side of the housing to provide a recess for the cover to be inserted, and the wireless module covers the recess to close the recess.

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