Wireless sensing structure of cylinder apparatus

Abstract

Provided is a wireless sensing structure with which radio waves are easily diffused from a wireless radio machine. Disclosed is a wireless sensing structure of a cylinder apparatus 40 provided with a self-power generation device 1 that generates power in accordance with variation of the position of a piston part in a housing 2 made of metal and that transmits the power as an electric signal. In a lid 62 made of resin, a recessed part 66 at the bottom surface and a U-shaped groove 63 at the surface part are in communication with each other through a through-hole 65 provided at the position of a starting end of the U-shaped groove. A wireless board 70 is attached to the recessed part 66, and an antenna 71 is inserted into the through-hole 65 and folded in order along the U-shaped groove 63 so as to be fixed. A depressed part 2d notched into a shape similar to the outer shape of the lid 62 such that the lid 62 is fitted thereinto is provided in a portion on the upper side of the housing 2, and the lid 62 closes the depressed part 2d.

Description

Wireless sensing structure for cylinder device

[0001] The present invention relates to a wireless sensing structure for a cylinder device used in a stand-alone power generating device that generates electricity and generates an electrical signal by utilizing mechanical fluctuations in a metal housing.

[0002] As a device that generates current and transmits mechanical fluctuations as electrical signals to the outside without a power source or connection to external electrical wiring, stand-alone power generating devices such as those disclosed in Patent Documents 1 to 3 are known. As shown in each of these patent documents, a tiny wireless radio is placed nearby the stand-alone power generating device. The stand-alone power generating device cooperates with the wireless radio to supply power generated by mechanical fluctuations, and the wireless radio then wirelessly transmits the occurrence of the mechanical fluctuations.

[0003] Furthermore, the present applicant has proposed an independent power generating device that generates electricity by directly utilizing external linear motion in patent applications No. 2023-166280 and No. 2024-3414, and has shown examples of applying the independent power generating device to cylinder devices such as clamping devices and pressure detectors.

[0004] JP 2009-516802 A JP 2022-552337 A JP 2018-153094 A

[0005] Metal blocks radio waves, but the housings of these cylinder devices are themselves made of metal. The stand-alone power generating device detects the movement of the piston inside the metal housing of the cylinder device and generates an electrical signal, which is then released wirelessly to the outside. There is a need for a wireless sensing structure that blocks weak radio waves as little as possible due to the metal housing.

[0006] The object of the present invention is to provide a wireless sensing structure that makes it easier for radio waves to spread from a wireless radio when an electrical signal from an autonomous power generating device that detects mechanical fluctuations within the metal housing of a cylinder device is radiated to the outside via wireless radio.

[0007] According to the present invention, in a wireless sensing structure for a cylinder device equipped with an independent power generating device that generates electricity in response to fluctuations in the position of a piston part within a metal housing and sends it out as an electrical signal, the wireless sensing structure comprises: a wireless board having an antenna erected from a board on which a wireless transmission LSI is mounted; and a resin lid body in which a recess on the bottom surface and a U-shaped groove on the surface surface are connected by a through-hole provided at the start of the U-shaped groove, the metal board is attached to the recess, the antenna is inserted into the through-hole, and the resin lid body is folded sequentially along the U-shaped groove and fixed; and a recessed portion into which the lid body fits is provided by cutting out a shape similar to the outer shape of the lid body in a part of the upper side of the housing, and the recessed portion is covered with the wireless module to seal the recessed portion.

[0008] According to the wireless sensing structure of the present invention, a recess is provided in a portion of the upper side of the housing, with a shape similar to the external shape of the wireless module cut out, into which the lid fits. By placing the wireless module over the recess, the metal of the housing in the horizontal direction that would obstruct the radio waves emitted from the antenna folded into the U-shaped groove is eliminated, making it easier for the radio waves to spread.

[0009] FIG. 1 is a diagram illustrating the stand-alone power generating device. FIG. 2 is a diagram illustrating components of the stand-alone power generating device. FIG. 3 is a diagram illustrating components of the stand-alone power generating device. FIG. 4 is a diagram illustrating the operation of the stand-alone power generating device. FIG. 5 is a perspective view of a cylinder device. FIG. 6 is a diagram illustrating a released state. FIG. 7 is a diagram illustrating an intermediate state. FIG. 8 is a diagram illustrating a locked state. FIG. 9 is a diagram illustrating a state in which the wireless module has been removed. FIG. 10 is a diagram illustrating the structure of the wireless module.

[0010] First, the stand-alone power generating device will be described. As for the stand-alone power generating device, the stand-alone power generating devices disclosed in Patent Documents 1 to 3 and the stand-alone power generating devices proposed in Japanese Patent Application Nos. 2023-166280 and 2024-3414 can be applied.

[0011] Here, we will describe the self-sustaining power generating apparatus proposed in Japanese Patent Application Nos. 2023-166280 and 2024-3414, which were not publicly known at the time of filing this application. In FIG. 1A , the self-sustaining power generating apparatus 1 includes a magnet unit 13 fixed to a housing 2 with bolts 23 and a coil unit 12 that can be moved in the core axis direction c1 by a ball-shaped probe 11. The magnet unit 13 includes a permanent magnet 14 and an upper magnetic flux path 15 and a lower magnetic flux path 16 made of soft magnetic material. Magnetic flux paths made of soft magnetic material are provided for the upper and lower magnetic poles of the permanent magnet 14, respectively. The two magnetic flux paths 15, 16 are U-shaped in side view, sandwiching the permanent magnet 14, with one magnetic flux path 15 on the inside and the other magnetic flux path 16 on the outside, and are arranged to overlap with a gap between them. Both ends of the magnetic flux path 15 are pole pieces 15a and 15b, and both ends of the magnetic flux path 16 are pole pieces 16a and 16b.

[0012] The coil unit 12 includes a core 17, a coil 19 wound around the core 17 via a bobbin 19a, and ring-shaped contact terminals 21 and 22 sandwiching the coil 19. Pole pieces 15a and 16a face each other as a pair on the front side of the coil 19, while pole pieces 15b and 16b face each other as a pair on the rear side of the coil 19. The core 17 has a front end 17a on the front side (right in the drawing) of its core axis direction c1, a core body 17b in the center, and a rear end 17c on the rear side (left in the drawing). The core 17 is cylindrical with its core axis direction c1 aligned radially from the centerline C. Hereinafter, in the drawings, the right side of the core axis direction c1 is referred to as the front side, and the left side is referred to as the rear side. The core body 17b accounts for most of the length of the core 17 in the core axis direction c1, and the coil 19 is wound around the core body 17b. Although not clearly visible in the drawing, the bobbin 19a is adhesively fixed to the magnetic flux path 15. The core body 17b and the coil 19 are not fixed, and the core body 17b can move in the core axis direction c1 via the hollow of the bobbin 19a, which is the center of the coil 19.

[0013] The core body 17b is made of a soft magnetic material. The front end portion 17a and the rear end portion 17c may be made of a soft magnetic material or a non-magnetic material. However, if they are made of a soft magnetic material, they must be spaced apart so as not to magnetically short-circuit the upper and lower magnetic flux paths 15, 16.

[0014] The core body 17b and the front end 17a, and the core body 17b and the rear end 17c have protrusions a and recesses b for fitting together. The outer peripheral surfaces between the core body 17b and the front end 17a and between the core body 17b and the rear end 17c are provided with sliding surfaces 17d and 17e, respectively, which are smaller in diameter than the other outer peripheries by a distance d. The contact terminals 21 and 22 are soft magnetic and fitted onto the outer peripheries of the sliding surfaces 17d and 17e, respectively, allowing the contact terminals 21 and 22 to move freely along the sliding surfaces 17d and 17e in the core axis direction c1 within the distance d. The large-diameter portion of the core body 17b, the front end 17a, and the rear end 17c restrict 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, and magnetic flux passes between the core body 17b and the contact terminals 21 and 22 without any magnetic gap.

[0015] The front end 17a of the core 17 abuts against the probe section 11, and when radial movement of the center line C is transmitted from the probe section 11 to the core 17, the rear end 17c of the core 17 moves in the core axis direction c1 relative to the magnet unit 13.

[0016] FIG. 2 is a diagram illustrating the coil unit 12 and contact terminals 21 and 22 in detail. Note that the coil 19 (and bobbin 19a) are indicated by dashed lines in the figure. When 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 end p that contacts the probe 11, a first base portion q that is larger in diameter than the sliding surface 17d, and a recess b that fits with the protrusion a of the core body 17b. The rear end 17c has a base portion r that contacts the elastic body 18, a second base portion s that is larger in diameter than the sliding surface 17e, and a recess b (FIG. 2) that fits with the protrusion a of the core body 17b. The contact terminals 21 and 22 are cylindrical with a height h, which is shorter than the distance d. Each of the contact terminals 21 and 22 has abutment surfaces 21a and 21b and abutment surfaces 22a and 22b on the front and back sides, respectively, which are perpendicular to the core axis direction c1.

[0017] 3 is a diagram showing the relationship between the magnet unit 13 and the core 17. The magnet unit 13 has a permanent magnet 14 sandwiched between upper and lower magnetic flux paths 15, 16, and is fixed to the housing 2 with bolts 23. The upper and lower magnetic flux paths 15, 16 are made by bending a plate material into a U-shape. The pole pieces 15a, 15b, 16a, 16b, which are the ends of the upper and lower magnetic flux paths 15, 16, respectively, are disposed with a gap between the core body 17b, the front end 17a, and the rear end 17c. Furthermore, this is to prevent the core body 17b, the front end 17a, and the rear end 17c from forming a magnetic flux path, as they do not come into contact with each other before, during, or after being pushed by the probe 11 or the elastic body 18 and moved.

[0018] The magnetic poles of the permanent magnet 14 appear in the pole pieces 15a, 16b of the upper and lower magnetic flux paths 15, 16. The pole pieces 15a, 15b of the upper magnetic flux path 15 and the pole pieces 16a, 16b of the lower magnetic flux path are arranged parallel to each other with a distance t between them. The pole pieces 15a, 16a are capable of contacting the front and back contact surfaces 21b, 21a of the contact terminal 21, respectively. The pole pieces 15b, 16b are capable of contacting the front and back contact surfaces 22a, 22b of the contact terminal 22, respectively. The pole pieces 15a, 15b, 16a, 16b are provided with arc-shaped notches x to increase the contact area with the contact terminals 21, 22. When the contact terminals 21 and 22 slide on the sliding surfaces 17d and 17e, the contact terminals 21 and 22 come into contact with the pole pieces 15a, 15b, 16a and 16b and are prevented from sliding, so the range over which the contact terminals 21 and 22 can move is within this distance t.

[0019] FIG. 4 illustrates the operation of the stand-alone power generating device 1. The rear end 17c of the core 17 of the stand-alone power generating device 1 abuts against the elastic body 18, which is a compression spring, housed in a spring chamber 24. When the core 17 moves rearward in the core axial direction c1, the elastic body 18 accumulates a resilient force, which is used to push the core 17 forward. The mechanism for pushing the core 17 forward is not limited to the elastic body 18; instead, a mechanism for supplying pressure oil or compressed air to an operating chamber and using the pressure to push the core 17 forward, as shown in the first embodiment described below, may also be used. In FIG. 4A , the rear pole piece 15b of the upper magnetic flux path 15, the contact terminal 22, the core body 17b, the contact terminal 21, and the front pole piece 16a of the lower magnetic flux path 16 are magnetically short-circuited to form a magnetic circuit φ1. The magnetic circuit φ1 is a circular path without leakage.

[0020] 4B shows the core 17 moving rearward in the core axis direction c1. The contact terminals 21 and 22 are pushed by the front end 17a and the larger-diameter portion of the core body 17b, respectively, and the rear pole piece 15b of the upper magnetic flux path 15 and the contact terminal 22, and the contact terminal 21 and the front pole piece 16a of the lower magnetic flux path 16 begin to separate, creating a gap g. The moving speed v1 of the core 17 and the contact terminals 21 and 22 up to this point is the moving speed of the probe unit 11. The magnetic force between the rear pole piece 15b of the upper magnetic flux path 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 path 16, weakens.

[0021] In Fig. 4C, the moment the magnetic force between the rear pole piece 16b of the lower magnetic flux path 15 and the contact terminal 22 and the magnetic force between the contact terminal 21 and the front pole piece 15a of the upper magnetic flux path 15 become dominant, the contact terminals 21 and 22 leave the state of moving speed v1, are accelerated on the sliding surfaces 17d and 17e, and collide with the pole pieces 15a and 16b, respectively. Note that Fig. 4B and Fig. 4C show the states before and after the contact terminals 21 and 22 are suddenly accelerated and move, even though the core 17 has hardly moved at all.

[0022] As shown in Figure 4C, the distance d between the sliding surfaces 17d and 17e is designed so that the rear ends of the sliding surfaces 17d and 17e are positioned at or beyond the rear pole piece 16b of the lower magnetic flux path 16 and the front pole piece 15a of the upper magnetic flux path 15, respectively. In this state, the front pole piece 15a of the upper magnetic flux path 15, the contact terminal 21, the core body 17b, the contact terminal 22, and the rear pole piece 16b of the lower magnetic flux path 16 are magnetically short-circuited to form a magnetic circuit φ2. The magnetic circuit φ2 also forms a complete circuit without leakage. Focusing on the core body 17b, the direction of the magnetic flux passing through the core body 17b is opposite to that of the magnetic circuit φ1 and the magnetic circuit φ2. The instantaneous switch from the magnetic circuit φ1 to the magnetic circuit φ2 results in a large change in magnetic flux.

[0023] FIG. 5 shows a perspective view of a cylinder device 40 equipped with an autonomous power generating apparatus 1. The cylinder device 40 includes a metal housing 2, a shaft member 5 that protrudes from the housing 2 and moves up and down, and a link clamp mechanism 30 consisting of links 30a and 30b attached to the end of the shaft member 5. The housing 2 has an integrated cylindrical lower portion B and a rectangular parallelepiped upper portion T. The lower portion B is where pressure oil or compressed air is supplied to move the shaft member 5 up and down. The upper portion T is where the wireless module 61 and the autonomous power generating apparatus 1 are installed. The cylinder device 40 operates the autonomous power generating apparatus 1 when the shaft member 5 is in the lowered position.

[0024] 6 shows a cross section of the cylinder device 40 equipped with the stand-alone power generating device 1. The shaft member 5 has a shaft body 5a formed from the top and a piston portion 5b having a larger diameter than the shaft body 5a. A stepped portion 5d is provided midway along the length of the shaft body 5a, and the diameter of the shaft body 5a above the stepped portion 5d is larger than that of the shaft body 5a below the stepped portion 5d.

[0025] In the cylinder device 40, pressure oil or compressed air or the like is supplied to a cylinder bore 3 drilled in the housing 2, and the piston portion 5b is raised and lowered. The cylinder bore 3 is a space formed inside the ceiling portion 2a, the bottom portion 2b, and a body wall 2c extending in the vertical direction, and between the body wall 2c. When pressure oil or compressed air or the like is supplied to the chamber 3a above the piston portion 5b, the piston portion 5b descends, and when pressure oil or compressed air or the like is supplied to the chamber 3b below, the piston portion 5b ascends.

[0026] A cylindrical hole 4 formed in the ceiling portion 2a of the housing 2 surrounds the shaft body 5a, and a portion of the shaft member 5 penetrates the ceiling portion 2a and protrudes outside the housing 2. In the drawing, the stroke range of the shaft member 5 is indicated by ST. This range indicates the vertical movement range of the position marked by an "*" on the shaft member 5 in the drawing.

[0027] A sleeve 51 is fitted onto the outer periphery of the shaft body 5a above the stepped portion 5d. The sleeve 51 is surrounded by the cylindrical bore 4. The lower end 51a of the sleeve 51 has a reduced diameter and is adapted to engage with the stepped portion 5d. The upper end 51b of the sleeve 51 has a limited range of movement by the ceiling portion 2a of the housing 2. In other words, even if the shaft body 5a rises, once the upper end 51b of the sleeve 51 abuts against the ceiling portion 2a of the housing 2, the sleeve 51 cannot rise any further, and only the shaft body 5a rises.

[0028] A displacement portion 53 is provided on the outer periphery of the sleeve 51 midway up its height. An opening 9 is drilled within the range of movement of the displacement portion 53. A ball-shaped probe portion 11 is fitted into the opening 9 and protrudes from it. The probe portion 11 in the opening 9 detects the displacement portion 53 and protrudes from the opening 9. The opening 9 faces the displacement portion 53, and the probe portion 11 overlaps the displacement portion 53, thereby converting the up and down movement of the shaft body 5a into movement in a direction perpendicular to the center line C (direction c1, radial direction of the center line C). The sleeve 51 is biased upward by an elastic body 55 whose base end is a fixed end 54 provided on the housing 2 side.

[0029] The motion of the probe 11 is transmitted to the front end 17a of the core 17 of the stand-alone power generating apparatus 1. The stand-alone power generating apparatus 1 converts the kinetic energy of the probe 11 into electrical energy, and supplies power to the wireless module 61 to drive it. The wireless module 61 wirelessly transmits a signal indicating that it has climbed over the obstacle.

[0030] Furthermore, the rear end portion 17c of the core 17 of the stand-alone power generating device 1 abuts against an elastic body 18, which is a compression spring, at the rear side. The elastic body 18 is housed in a spring chamber 24, and when the core 17 moves in the core axial direction c1, a resilient force is accumulated in the spring chamber 24. The resilient force accumulated in the elastic body is used as a force to push the core forward when the shaft body 5a descends and the probe part 11 descends from the displacement part 8.

[0031] 7, the piston portion 5b of the cylinder device 40 is lowered, and the link clamp mechanism 30 has released the workpiece W. The state is shown in which the stepped portion 5d of the shaft body 5a presses down the sleeve 51, causing the probe portion 11 to come out of the recessed displacement portion 43.

[0032] 8 shows the cylinder device 40 in a state where sensing is started by the stand-alone power generating apparatus 1 during the process of switching from the released state to the locked state. The sleeve 51 is pushed up by the elastic body 32, and the probe 11 is about to fall into the displacement portion 53. When the probe 11 overlaps the displacement portion 53, the stand-alone power generating apparatus 1 can operate the wireless module 61 to notify the outside world by wireless signal.

[0033] Figure 8 shows the cylinder device 40 in a locked state. The sleeve 51 cannot rise, and only the shaft body 5a is raised. The probe 11 has fallen into the displacement portion 53. Therefore, the range in which the sleeve 51 engages with the stepped portion 5d and descends in conjunction with it 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 ceiling portion 2a in Figure 7.

[0034] According to the cylinder device 40, the probe portion 11 in the opening 9 overlaps with the displacement portion 53, thereby converting the up and down movement of the shaft body 5a into movement perpendicular to the center line C (direction c1, radial direction of the center line C). Therefore, when the piston portion 5b is in the lowered position, the self-sustaining power generating device 1 can operate the wireless module 61 and notify the outside by wireless signal.

[0035] 9 shows the wireless module 61 removed from the housing 2. Here, the long side direction of the upper part T in a plan view is defined as the x direction (the same direction as the c1 direction), 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 stand-alone power generating unit 1 is arranged in the c1 direction of the shaft member 5 within the housing 2.

[0036] The housing 2 has a recess 2d into which the wireless module 61 fits. The recess 2d is formed by cutting out the entire upper side of the rectangular upper portion T of the housing 2 in the y direction and a portion of the upper side in the x direction that is continuous with the upper side. The position of the recess 2d corresponds to a position directly above the stand-alone power generating device 1. The recess 2d has a shape similar to the outline of the wireless module 61, and the wireless module 61 is placed over the recess 2d from above the housing 2 to close the recess 2d. The wireless module 61 is fixed in place with bolts 60.

[0037] 10 is a diagram showing the details of the wireless module 61. The wireless module 61 includes a cover 62 made of a resin such as polyphenylene sulfide or polyacetal that does not easily block radio waves, and a wireless board 70 on which a wireless transmission LSI (not shown) is mounted and an antenna 71 is provided. Because the cover 62 defines the external shape of the wireless module 61, the recessed portion 2d is similar in shape to the external shape of the cover 62. The wireless module 61 is placed over the recessed portion 2d of the housing 2 via a packing 67 that prevents dust from entering.

[0038] 10A-10D are diagrams showing the cover 62, with FIG. 10A being a plan view, FIG. 10B being a front view, FIG. 10C being a Y1-Y1 cross-sectional view, and FIG. 10D being a bottom view. FIG. 10E and FIG. 10F are a plan view and a Y3-Y3 cross-sectional view of the packing 67. FIG. 10G is a side view and a plan view of the wireless board 70.

[0039] 10I, the wireless board 70 is mounted in a recess 66 provided in the bottom surface of the lid 62. In Fig. 10J, a U-shaped groove 63 is provided on the surface of the lid 62. The U-shaped groove 63 is formed by connecting an x-direction groove 63a, a y-direction groove 63b, and an x-direction groove 63c in series. A through hole 65 communicates with the start position of the U-shaped groove 63 and the recess 62d via the through hole 65, and the antenna 71 adhered to the recess 66 is inserted into the through hole 65 and emerges in the U-shaped groove 63.

[0040] The antenna 71 is a quarter-wave antenna. The antenna 71 passes through the through-hole 65 and is folded and fixed in place along the x-direction groove 63a, y-direction groove 63b, and x-direction groove 63c in that order. However, folding the antenna 71 too small would cause interference between the folded portions, so the y-direction groove 63b separates the x-direction groove 63a and the x-direction groove 63c. Furthermore, a recess 2d is cut out in a shape similar to the external shape of the wireless module 61 in a portion of the upper side of the housing 2, into which the lid 62 fits. The wireless module 61 is placed over the recess 2d, so that the metal housing 2 does not obstruct the portion of the antenna 71 in the y-direction groove 63b in a horizontal direction in a plan view. Furthermore, because the recess 2d cuts out a portion of the housing 2 at the x-direction grooves 63a and 63c, radio wave interference is less likely to occur.

[0041] Furthermore, since the entire length of the antenna 71 is fixed to the resin lid 62, it is less susceptible to external mechanical shocks in the environment in which the cylinder device 40 is installed.

[0042] REFERENCE SIGNS LIST 1 Standalone power generating device 2 Housing 2a Ceiling portion 2b Bottom portion 2c Body wall 2d Recessed portion 3 Cylinder hole 4 Cylindrical hole 5 Shaft member 5a Shaft body 5b Piston portion 5d Stepped portion 8 Displacement portion 9 Opening 11 Probing portion 12 Coil unit 13 Magnet unit 14 Permanent magnet 15, 16 Magnetic flux path 15a, 15b, 16a, 16b Pole piece 17 Core 17a Front end portion 17b Core body 17c Rear end portion 17d Sliding surface 17d, 17e Sliding surface 17e Sliding surface 18 Elastic body 19 Coil 19a Bobbin 21 Contact terminal 21, 22 Contact terminal 21a, 21b Abutting surface 21b, 21a Abutting surface 22 Contact terminals 22a, 22b: contact surface 23: bolt 24: spring chamber 30: link clamp mechanism 30a, 30b: link 32: elastic body 40: cylinder device 43: displacement portion 51: sleeve 51a: lower end 51b: upper end 53: displacement portion 54: fixed end 55: elastic body 60: bolt 61: wireless module 62: lid 62d: recess 63: U-shaped groove 65: through hole 66: recess 67: packing 70: wireless board 71: antenna

Claims

1. A wireless sensing structure for a cylinder device equipped with a stand-alone power generating device that generates electricity in response to fluctuations in the position of the piston within a metal housing and sends it out as an electrical signal, comprising: a wireless board on which an antenna is erected from a board on which a wireless transmission LSI is mounted; and a resin lid body in which a recess on the bottom surface and a U-shaped groove on the surface surface are connected by a through-hole provided at the start of the U-shaped groove, the metal board is attached to the recess, the antenna is inserted into the through-hole, and the resin lid body is folded in order along the U-shaped groove and fixed in place; and a part of the upper side of the housing has a shape similar to the external shape of the lid body cut out, and a recess into which the lid body fits is provided, and the wireless module is placed over the recess to close the recess.

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