Cylinder device

Abstract

Provided is a cylinder device capable of detecting the position of a piston without the need to prepare an electricity supply environment. A cylinder device 50 comprises a shaft member 5 that is moved up and down in the direction of a center line C by pressurized oil, compressed air, or the like. A self-sustaining electric generation device 10 is activated by the up and down movement of the shaft member 5. An operation groove 8 is moved corresponding to the movement of the shaft member 5. An upper wall and a lower wall of the operation groove 8 abut an input member 13 of the self-sustaining electric generation device 10, and, when the operation groove 8 further pushes the input member 13, the self-sustaining electric generation device 10 is activated.

Description

Cylinder Device

[0001] The present invention relates to a cylinder device that detects the position of a piston.

[0002] Cylinder devices are used in a variety of applications, such as clamping devices and pressure detection devices. For example, in clamping devices, a piston is operated to fix a clamped object, such as a workpiece, mold, or tool, to a table or robot hand. Release and lock operations are determined based on the position of the piston. A clamping failure occurs when the piston is not positioned between the release and lock positions. Cylinder devices are equipped with a mechanism for detecting the piston position as an operating state. For example, a cylinder device disclosed in Patent Document 1 has a passage that is closed or opened depending on the position of the piston, and compressed air is supplied to the passage to detect the piston position based on the flow state of the air. Patent Document 2, for example, discloses a technology in which a coil and a magnet are installed inside the cylinder device, and the overlap distance between the coil and the magnet is changed depending on the moving position of the piston, thereby detecting the operating state of the cylinder device as a change in coil inductance.

[0003] Cylinder devices that use compressed air to detect their operating state require the installation of a compressed air source, the routing of the compressed air, and an environment for supplying power to the compressed air source. Also, in technology that uses changes in inductance to detect the operating state, it is necessary to prepare an environment for supplying power to the cylinder device so that current can be supplied to the coil.

[0004] As a device that generates current independently and transmits physical fluctuations to the outside without a power source or connection to external electrical wiring, a stand-alone power generating device such as that shown in Patent Documents 3 and 4 is known. As shown in both patent documents, a very small 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 physical fluctuations, and the wireless radio then wirelessly transmits the occurrence of the physical fluctuations.

[0005] The technologies of Patent Documents 3 and 4 disclose a magnetic circuit that passes through a central opening of an excitation coil, and upper and lower moving pieces that are connected to the upper and lower poles of a permanent magnet, with both ends of the magnetic circuit disposed between the upper and lower moving pieces, and by swinging the upper and lower moving pieces, one end of the magnetic circuit comes into contact with the upper moving piece and the other end of the magnetic circuit comes into contact with the lower moving piece to a first extreme position, and the other end of the magnetic circuit comes into contact with the upper moving piece and one end of the magnetic circuit comes into contact with the lower moving piece to a second extreme position, thereby varying the direction of the magnetic flux of the magnetic circuit. The electrical energy generated by the excitation coil operates a wireless module to perform wireless transmission.

[0006] Patent No. 7246686 Publication Patent No. 7366386 Publication Special Publication No. 2009-516802 Publication Special Publication No. 2022-552337 Publication

[0007] In the technology of the stand-alone power generating device disclosed in Patent Documents 3 and 4, the magnetic circuit and the permanent magnet change their relative positions in response to external physical fluctuations by swinging about a predetermined rotation axis.

[0008] FIGS. 1A, 1B, and 1C show schematic diagrams of an independent power generating apparatus 10 disclosed in Patent Documents 3 and 4. FIG. 1D is a perspective view of a commercially available product relating to this technology, and FIG. 1E is a front view seen from the direction of arrow R. The operation of the independent power generating apparatus 10 will be briefly described. In this embodiment, an electric coil 16 is magnetically coupled to a base 14c of a first ferromagnetic element 14. The first ferromagnetic element 14 can swing around a rotation axis φ. A second ferromagnetic element 12a and a third ferromagnetic element 12b are arranged with a permanent magnet 15 sandwiched between them. In the state shown in FIG. 1B, the leg 14a of the first ferromagnetic element 14 contacts the third ferromagnetic element 12b, and the leg 14b contacts the second ferromagnetic element 12a. The swing angle of the ferromagnetic element 14 about the rotation axis φ is an angle s. In the state shown in FIG. 1C, the swing angle is reversed, being an angle s. When viewed from the base 14c of the first ferromagnetic element 14, the direction of the magnetic flux is reversed between the state shown in Figure 1B and the state shown in Figure 1C. By rapidly switching between the state shown in Figure 1B and the state shown in Figure 1C, the electric coil 16 generates electricity. An input member 13 is disposed on the first ferromagnetic element 14. The input member 13 receives an external physical fluctuation and causes the energy converter to transition to the states shown in Figures 1B and 1C. If a spring element is not used as the input member 13, the first ferromagnetic element 14 swings, and when the swing angle with respect to the rotation axis φ exceeds zero, the first ferromagnetic element 14 is attracted to the magnetic force of either the second ferromagnetic element 12a or the third ferromagnetic element 12b. If a spring element is used as the input member 13, the external physical fluctuation exceeds the holding force of the permanent magnet 15, causing a rapid reversal between the state shown in Figure 1B and the state shown in Figure 1C.

[0009] On the other hand, the range in which the first ferromagnetic element 14 oscillates, i.e., the range required for the input member 13 to operate, is smaller than the distance the piston of the cylinder device moves, so the piston and input member 13 cannot be connected and moved.

[0010] An object of the present invention is to provide a cylinder device capable of detecting the position of a piston by utilizing a stand-alone power generating device that converts external physical motion into oscillation of a ferromagnetic element to generate electricity.

[0011] The cylinder device of the present invention is equipped with a shaft member that moves up and down along its centerline using pressurized oil or compressed air, etc. The up and down movement of the shaft member activates the self-sustaining power generating device. The vertical width of the operating groove is set, and the input member of the self-sustaining power generating device is inserted into the groove, and the positions of the upper and lower walls of the operating groove are moved in accordance with the movement of the shaft member. When the upper and lower walls of the operating groove abut against the input member of the self-sustaining power generating device and are further pressed, the self-sustaining power generating device is activated.

[0012] According to the cylinder device of the present invention, the up and down movement of the shaft member of the cylinder device is provided as an input to an independent power generating device that generates electricity by converting external physical movement into the oscillation of a ferromagnetic element, thereby making it possible to detect the position of the piston without the need to install a compressed air source, route the compressed air, or prepare an environment for supplying power to the compressed air source or coil.

[0013] FIG. 1 is a diagram illustrating an independent power generating device. FIG. 2 is a diagram illustrating a cylinder device of a first embodiment. FIG. 3 is a diagram illustrating the first embodiment (released state). FIG. 4 is a diagram illustrating the first embodiment (intermediate state). FIG. 5 is a diagram illustrating the first embodiment (locked state). FIG. 6 is a diagram illustrating the second embodiment (released state). FIG. 7 is a diagram illustrating the second embodiment (locked state). FIG. 8 is a diagram illustrating the third embodiment (released state). FIG. 9 is a diagram illustrating the third embodiment (locked state). FIG. 10 is a diagram illustrating the fourth embodiment (released state, locked state). FIG. 11 is a diagram illustrating the fourth embodiment (slip state). FIG. 12 is a diagram illustrating the fifth embodiment.

[0014] The cylinder device described in each embodiment below includes a shaft member that moves up and down using pressurized oil or compressed air, etc. The cylinder device in each embodiment is limited in size, and the independent power generating device cannot be installed anywhere in the up and down stroke of the shaft member. The location where it can be installed is above the stroke range of the piston part of the shaft member, and the number is limited to one. The states that the cylinder device can be in include a locked state, a released state, a clamp failure, a slip state, etc. The independent power generating device is installed within the cylinder device depending on which state of the cylinder device is to be detected.

[0015] In each embodiment, the input member of the self-sustaining power generating device abuts against the upper and lower walls of an operating groove formed by a groove with a length in the axial direction, and is operated by further movement of these walls, but each embodiment differs depending on how the operating groove is formed and which state of the cylinder device is detected.

[0016] [First embodiment] Fig. 2A shows a perspective view of a cylinder device 50 equipped with an independent power generating device 10. Fig. 2B shows a plan view. The cylinder device 50 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 at the end of the shaft member 5. The housing 2 has a shape in which a cylindrical lower portion BM and a rectangular parallelepiped upper portion TP are integrated.

[0017] The lower portion BM is a portion to which pressure oil or compressed air is supplied to move the shaft member 5 up and down. The upper portion TP is a portion to which the wireless module 41 and the stand-alone power generating apparatus 10 are installed. FIG. 2B shows the wireless module 41 removed from the recessed portion 2d of the housing 2. The wireless module 41 has a wireless transmitting circuit 44 (see FIG. 3) and an antenna 43 mounted on a cover body 42 made of a resin such as polyphenylene sulfide or polyacetal that does not easily block radio waves. The position of the recessed portion 2d corresponds to the position directly above the stand-alone power generating apparatus 10.

[0018] 3 shows a cross section of the cylinder device 50 equipped with the stand-alone power generating device 10. The cylinder device 50 is equipped with a shaft member 5 that moves up and down. The stand-alone power generating device 10 is installed in the housing 2 together with a wireless module 41.

[0019] The shaft member 5 includes a shaft body 5a formed from the top to the bottom and a piston portion 5b with a larger diameter than the shaft body 5a. The cylinder device 50 receives pressure oil or compressed air, etc., through a cylinder bore 3 drilled in the housing 2, which moves the piston portion 5b up and down. The cylinder bore 3 is a space defined by a ceiling portion 2a, a bottom portion 2b, and a vertically extending barrel wall 2c. When pressure oil or compressed air, etc., is supplied to the chamber 3a above the piston portion 5b, the piston portion 5b descends. When pressure oil or compressed air, etc., is supplied to the chamber 3b below the piston portion 5b, the piston portion 5b ascends. A cylindrical bore 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. The stroke range of the shaft member 5 is indicated by ST in the figure. This range indicates the vertical movement range of the position marked with an asterisk (*) on the shaft member 5 in the figure.

[0020] A stepped portion 5d is provided 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 below. 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 the ceiling portion 2a of the housing 2, the sleeve 51 cannot rise any further, and only the shaft body 5a rises. In this way, the distance the sleeve 51 moves is limited relative to the vertical movement of the shaft body 5a.

[0021] An operating groove 53 having a width t in the direction of the center line C is provided on the outer periphery of the sleeve 51 midway along its height. The sleeve 51 is biased upward by an elastic body 55 having a fixed end 54 on the housing 2 as its base end. The width t is set based on the distance the sleeve 51 moves, the distance the first ferromagnetic element 14 ( FIG. 1 ) moves through a swing angle s, and the thickness of the input member 13. When the input member 13 is configured as a spring element, the width t of the operating groove 53 is made larger than when a spring element is not used, taking into account the deflection of the spring element. An opening 9 is drilled in the housing 2 within the range of movement of the operating groove 53. The stand-alone power generating device 10 installed in the housing 2 inserts the input member 13 into the operating groove 53 through the opening 9. To insert the input member 13 into the operating groove 53, the thickness of the input member 13 is thinner than the width t.

[0022] The input member 13 abuts against the upper and lower walls in the direction of the center line C of the operating groove 53, and detects the physical movement of the sleeve 51 by pushing the first ferromagnetic element 14 to move a distance equivalent to the swing angle s.

[0023] 3, the piston portion 5b of the cylinder device 50 is in a lowered position, and the link clamp mechanism 30 has released the workpiece W. The stepped portion 5d of the shaft body 5a pushes down the sleeve 51, and the upper wall of the operation groove 53 abuts against the input member 13, showing the state immediately after the sleeve 51 is further pushed down. In other words, this is the state immediately after the stand-alone power generating device 10 has activated the wireless transmission circuit 44 to notify the outside world by wireless signal.

[0024] 4 shows the cylinder device 50 in the process of switching from the released state to the locked state, or from the locked state to the released state. The sleeve 51 is pushed up by the elastic body 55, and the input member 13 is separated from the upper wall of the operation groove 53 and is pushed up by the lower wall. When the input member 13 is pushed up, the stand-alone power generating device 10 can operate the wireless transmission circuit 44 to notify the outside world by wireless signal.

[0025] Figure 5 shows the cylinder device 50 in a locked state. The sleeve 51 cannot rise, and only the shaft body 5a is raised. The input member 13 remains in contact with the lower wall of the operation groove 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 in the process of the shaft member 5 stroking. This range corresponds to the distance ex1 between the upper end 51b of the sleeve 51 and the ceiling portion 2a in Figure 3.

[0026] The reason why the input member 13 can move freely within the width of the operation groove 53 is so that when the input member 13 moves due to movement of the upper or lower wall of the operation groove 53 and is drawn into the holding force of the permanent magnet 15 (when the state in FIG. 1B suddenly switches from the state in FIG. 1C ), the input member 13 can move independently, away from the movement of the sleeve 51. Furthermore, the reason why the difference between the width t and the distance ex1 is the movable range of the input member 13 in the stand-alone power generating device 10 is because the input member 13 will be damaged if it greatly exceeds the movable range.

[0027] According to the cylinder device 50 of the first embodiment, the distance that the sleeve 51 moves can be limited relative to the distance that the shaft body 5a moves in the vertical direction. The input member 13 moves within the limited range while abutting against the upper or lower wall of the operation groove 53 provided in the sleeve 51, and can operate the wireless module 41 to notify the outside by wireless signal.

[0028] Second Embodiment A cylinder device 60 of the second embodiment is a modified example of the cylinder device 50. In Fig. 6, the same components as those of the cylinder device 50 in Fig. 3 are given the same reference numerals, and a description thereof will be omitted. The cylinder device 60 also has a link clamp mechanism 30 consisting of links 30a and 30b, and can clamp a workpiece W at a point of application 30c. In the figure, the process of the stroke of the shaft member 5 is indicated by a range ST. This range indicates the range of movement up and down in the direction of the center line C of the position marked with an "*" on the shaft member 5 in the figure.

[0029] The shaft member 5 comprises a shaft body 5a formed from top to bottom and a piston portion 5b having a larger diameter than the shaft body 5a. A stepped portion 5d is provided along the length of the shaft body 5a, and the diameter of the shaft body 5a is larger above the stepped portion 5d than below. A sleeve 61 is fitted onto the outer periphery of the shaft body 5a. The bore 4 surrounds the sleeve 61. The lower end 61a of the sleeve 61 has a reduced diameter and is adapted to be caught on the stepped portion 5d. The upper end 61b of the sleeve 61 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 with the lower end 61a caught on the stepped portion 5d, once the upper end 61b of the sleeve 61 abuts against the ceiling portion 2a of the housing 2, the sleeve 61 cannot rise any further and only the shaft body 5a rises.

[0030] A braking member 64 is attached to the outer periphery of the sleeve 61. The braking member 64 is a member that applies a brake to the up-down movement of the sleeve 61 (toward the center line C) by elastic force. For example, a retaining ring, an O-ring, a rectangular rubber, or the like can be used. A retaining ring is a roughly ring-shaped (or C-shaped) spring steel member with a slit. The shaft member 5 further has a stepped portion 5f below the stepped portion 5d. The stepped portion 5f also serves as the upper surface of the piston portion 5b. The lower end 61a of the sleeve 61 abuts against the stepped portion 5f as the piston portion 5b rises. When the lower end 61a of the sleeve 61 engages the stepped portion 5d, the sleeve 61 rises as the piston portion 5b rises, regardless of the braking force applied by the braking member 64. In this way, the distance the sleeve 61 moves relative to the distance the shaft body 5a moves in the up-down direction is limited.

[0031] An operation groove 63 is provided on the outer periphery of the sleeve 61 midway up the height thereof. An opening 9 is drilled within the range of movement of the operation groove 63. The input member 13 in the opening 9 comes into contact with the upper or lower wall of the operation groove 63 and is operated.

[0032] 6, the piston portion 5b of the cylinder device 60 is in a lowered position, and the link clamp mechanism 30 has released the workpiece W. This shows the state immediately after the stepped portion 5d of the shaft body 5a has pressed down the sleeve 51, and the upper wall of the operation groove 53 has pressed down the input member 13. In other words, this is the state immediately after the stand-alone power generating device 10 has activated the wireless transmission circuit 44 to notify the outside world by wireless signal that it has reached the release position.

[0033] Thereafter, in the state in the middle of switching from the released state to the locked state, the downward movement of the sleeve 61 is braked by the brake member 64, and the sleeve 61 is held in the position shown in FIG.

[0034] FIG. 7 shows the cylinder device 60 in a locked state. This is the state immediately after the stand-alone power generating apparatus 10 activates the wireless transmission circuit 44 to notify the outside world that it has reached the locked position via a wireless signal. The lower end 61a of the sleeve 61 abuts against the stepped portion 5f, which is the upper surface of the piston portion 5b, and the sleeve 61 rises, regardless of the braking action of the braking member 64. The input member 13 has left the upper wall of the operation groove 43 and is being pushed up by the lower wall. When the input member 13 is pushed up, the stand-alone power generating apparatus 10 activates the wireless transmission circuit 44 to notify the outside world via a wireless signal. From the state shown in FIG. 6 to the state shown in FIG. 7, the sleeve 61 moves a distance ex2 (see FIG. 6).

[0035] When the lower end 61a of the sleeve 61 engages with the stepped portion 5f and the piston portion 5b rises by a second range ex22 (shorter than the distance ex2), the input member 13 abuts against the lower wall of the operation groove 63. In Figure 7, within the stroke range ST of the shaft member 5, the second range ex22 is shown as the range from when the sleeve 61 engages with the stepped portion 5f and moves until the input member 13 abuts against the lower wall of the operation groove 63. This is the final position of the upward stroke of the shaft member 5. Conversely, even before the state of Figure 7 transitions to the state of Figure 6, the lower end 61a of the sleeve 61 engages with the stepped portion 5d and moves by the distance ex2.

[0036] 7, during the process of range ST, a first range ex21 is shown, from when the sleeve 61 engages with the stepped portion 5d until the input member 13 abuts against the lower wall of the operation groove 63. The first range and the second range are equal to the width t of the operation groove 63.

[0037] According to the cylinder device 60 of the second embodiment, the distance that the sleeve 61 moves can be limited relative to the distance that the shaft body 5a moves in the vertical direction. When the piston portion 5b is in the lowered position or the raised position, the stand-alone power generating device 10 can operate the wireless transmitting circuit 44 to notify the outside by wireless signal.

[0038] [Third embodiment] A cylinder device 70 of the third embodiment is an example in which the up and down movement of the shaft member 5 is converted into rotational movement of a sleeve 71 to operate the input member 13 of the stand-alone power generating apparatus 10. In Figure 8, the same components as those of the cylinder device 50 in Figure 3 are designated by the same reference numerals, and description thereof will be omitted.

[0039] In FIG. 8A , a sleeve 71 is fitted onto the shaft body 5a. The bore 4 surrounds the sleeve 71. The sleeve 71 is restricted in its vertical movement by a stop ring 72, but is able to rotate around the shaft body 5a. A rotation mechanism 73 is provided between the shaft body 5a and the sleeve 71. The rotation mechanism 73 includes a guide groove 74 and a ball 75 (shown in dashed lines). The guide groove 74 is configured by a spiral rotation groove 74a and a linear groove 74b connected upward. The ball 75 is inserted into the guide groove 74. The ball 75 is rotatably supported in a support opening 78 (same position as the ball 75 shown in dashed lines) provided on the inner wall of the sleeve 71. When the piston portion 5b moves between the uppermost position and the lowermost position, the rotation mechanism 73 rotates the sleeve 71 by a predetermined angle (90 degrees in this example). In this way, the sleeve 71 does not move up and down relative to the distance that the shaft body 5a moves up and down.

[0040] 8B , an operation groove 76 that is angled spirally with respect to a center line C and an operation groove 77 that runs along a circumference centered on the center line C are provided on the outer periphery of the sleeve 71, and these two grooves are continuously provided within a predetermined angle range (90 degrees) from the center line C. An opening 9 is perforated in a range facing the operation grooves 76 and 77. As the sleeve 71 rotates 90 degrees, the operation grooves 76 and 77 continuously face the opening 9. The input member 13 that protrudes from the opening 9 comes into contact with the lower walls of the operation grooves 76 and 77 during this process and is operated.

[0041] 8A shows the cylinder device 70 in the released state. The piston portion 5b is in the lowest position, and the input member 13 overlaps the operation groove 76. When the input member 13 abuts against the lower wall of the operation groove 76, the stand-alone power generating apparatus 10 activates the wireless transmission circuit 44 to notify the outside world by wireless signal that it has reached the released position.

[0042] Figure 9 shows the cylinder device 70 in the locked state. The piston portion 5b is in its uppermost position, and the input member 13 abuts against the upper wall of the operation groove 77. When the input member 13 abuts against the upper wall of the operation groove 77 and pushes it up, the stand-alone power generating unit 10 activates the wireless transmission circuit 44 to notify the outside world by wireless signal that the locked position has been reached. According to the third embodiment, the sleeve 71 does not move up and down, but only rotates. The operating range of the input member 13 can be limited by the shapes of the upper and lower walls of the operation grooves 76 and 77.

[0043] [Fourth Embodiment] A cylinder device 80 according to the fourth embodiment is a cylinder device used as a clamping device. In FIG. 10 , components identical to those of the cylinder device 50 in FIG. 3 are designated by the same reference numerals and will not be described again. The cylinder device 80 includes a tapered shaft portion 5e and a gripping member 81 that surrounds the tapered shaft portion 5e and engages with a hole Wh provided in a workpiece W when the tapered shaft portion 5e descends. The tapered shaft portion 5e is the distal end of a shaft member 5, which includes a shaft body 5a and a piston portion 5b, as in the second and third embodiments. The shaft body 5a, piston portion 5b, and tapered shaft portion 5e of the shaft member 5 move vertically as a unit. The lower end of the gripping member 81 abuts against a sleeve 82 that surrounds the shaft member 5 from above. The sleeve 82 is surrounded by a cylindrical bore 4. When the gripping member 81 descends, the sleeve 82 also descends, and when the sleeve 82 rises, the gripping member 81 also rises.

[0044] When pressure oil or compressed air is supplied to the upper chamber 3a of the cylinder bore 3, the piston portion 5b descends and the sleeve 82 ascends. When pressure oil or compressed air is supplied to the lower chamber 3b of the cylinder bore 3, the piston portion 5b ascends. By descending the piston portion 5b and drawing the shaft member 5 toward the seating surface ss, the tapered shaft portion 5e expands the diameter of the grip claws 81a, causing them to engage with the inner surface of the hole Wh, and the grip member 81 is further drawn toward the seating surface ss, thereby fixing the workpiece W. At this time, if the grip member 81 properly engages with the hole Wh, it will not descend in conjunction with the drawing of the grip member 81. Note that even if the grip member 81 descends slightly, it will be pushed up by the piston portion 5b and return to its original position when it is released.

[0045] Fig. 10A shows the state before the gripping member 81 pulls in the workpiece W, and Fig. 10B shows the state after the workpiece W has been pulled in and clamped. Pressurized oil or compressed air is supplied to the upper chamber 3a, causing the piston portion 5b to descend and expand the chamber 3a. A concave operating groove 83 is provided on the outer periphery midway up the height of the sleeve 82. An opening 9 is perforated within the range of movement of the operating groove 83. The input member 13 within the opening 9 abuts against the upper and lower walls of the operating groove 83 and is actuated by further movement. In the state of Fig. 10A, the input member 13 abuts against the lower wall of the operating groove 83 and is pushed up, while in Fig. 10B the input member 13 is in a free state.

[0046] 11 shows that an attempt to clamp the workpiece W failed, resulting in a slippage. A slippage occurs when the hole Wh in the workpiece W is larger than expected or the grip claws 81a are damaged. In such cases, the grip member 81 slips without engaging with the hole Wh, causing the piston portion 5b to drop more than expected.

[0047] Because the grip member 81 is not engaged with the hole Wh, the grip member 81 and the sleeve 82 descend in conjunction with the descent of the piston portion 5b. When the input member 13 descends to a position where it abuts against the upper wall of the operation groove 73 and then descends further, the stand-alone power generating device 10 activates the wireless transmission circuit 44 to notify the outside world by wireless signal that a grip failure has occurred.

[0048] The shaft body 5a and the sleeve 82 move independently in the vertical direction, but not by the same distance, by an amount corresponding to the amount of widening of the grip member 81. According to the cylinder device 80 of the fourth embodiment, the operating position of the input member 13 can be set according to the sleeve 82. Note that, in the grip member 81 described above, the diameter of the grip claws 81a is widened by the tapered shaft portion 5e due to bending, but the grip claws 81a may also be moved left and right.

[0049] Fifth Embodiment A cylinder device 90 according to a fifth embodiment is a cylinder device used for pressure detection. The same components as those in the cylinder device 50 of FIG. 3 are designated by the same reference numerals, and a description thereof will be omitted. The cylinder device 90 includes a safety valve 91, an elastic body 93, adjustment screws 94a and 94b, and a spring seat 92. A hole-shaped positioning hole 99 is provided midway along the height of the shaft body 5a. One end of the elastic body 93 acts by a movable end 95 to press a ball 96 into the positioning hole 99. The spring seat 92 determines the position of the other end of the elastic body 93. The cylinder bore 3 is in communication with a path P through which a fluid whose pressure is to be detected flows.

[0050] A hole-shaped operation groove 98 is provided midway along the height of the shaft body 5a. Meanwhile, an opening 9 perpendicular to the center line C is drilled in the peripheral wall surface of the cylindrical bore 4. The vertical width of the operation groove 98 corresponds to the range of movement of the piston portion 5b. The input member 13 protruding from the opening 9 abuts against and is pushed against the upper and lower walls of the operation groove 98, thereby operating the stand-alone power generating device 10.

[0051] The biasing force of the elastic body 93 can be adjusted using the adjustment screws 94a, 94b and the spring seat 92. The piston 5b is subjected to the pressure of the fluid in the path P. Even if the piston 5b attempts to move upward, it cannot push the ball 96 to the right in the direction c1 unless it overcomes the biasing force of the elastic body 93 ( FIG. 10A ). On the other hand, if the pressure of the fluid in the path P exceeds the biasing force of the elastic body 93, the shaft body 5a moves upward, and the lower wall of the operation groove 98 operates the input member 13 ( FIG. 10B ). At this time, the stand-alone power generating device 10 can operate the wireless transmission circuit 44 to notify the outside world by wireless signal that the specified pressure has been exceeded. When the vertical movement distance of the piston 5b is small, as in the cylinder device 90 of the fifth embodiment, the width t of the operation groove 98 can be determined based on the movement distance of the piston 5b itself, the swing angle s, and the thickness of the input member 13, rather than the movement distance of the sleeves 51, 61, 71, and 82 as in the previous embodiments, thereby allowing the input member 13 to be operated.

[0052] 2 Housing 2a Ceiling portion 2b Bottom portion 2c Body wall 2d Recessed portion 3 Cylinder hole 3a Upper chamber 3b Lower chamber 4 Cylindrical hole 5 Shaft member 5a Shaft main body 5b Piston portion 5d Stepped portion 5e Tapered shaft portion 5f Stepped portion 8 Operation groove 9 Opening 10 Self-sustaining power generating device 12a Second ferromagnetic element 12b Third ferromagnetic element 13 Input member 14 First ferromagnetic element 14a Leg portion 14b Leg portion 14c Base portion 15 Permanent magnet 16 Electric coil 30 Link clamp mechanism 30a, 30b Link 30c Point of application 41 Wireless module 42 Cover body 43 Antenna 44 Wireless transmitting circuit 50 Cylinder device 51 Sleeve 51a Lower end 51b Upper end 53 Operation groove 54 Fixed end 55 Elastic body 60 Cylinder device 61 Sleeve 61a Lower end 61b Upper end 63 Operation groove 64 Braking member 70 Cylinder device 71 Sleeve 72 Stop ring 73 Swivel mechanism 74 Guide groove 74a Swivel groove 74b Linear groove 75 Ball 76, 77 Operation groove 78 Support opening 80 Cylinder device 81 Grip member 81a Grip claw 82 Sleeve 83 Operation groove 90 Cylinder device 91 Safety valve 92 Spring seat 93 Elastic body 94 Guide groove 94a, 94b Adjusting screw 95 Movable end 96 Ball 98 Operation groove 99 Positioning hole

Claims

1. A cylinder device comprising: a piston section that moves up and down; a shaft body connected to the piston section; a sleeve that surrounds the shaft body and is urged in an upward direction; a cylindrical bore that surrounds the sleeve and has an opening midway up the length; and an independent power generating device; the sleeve has an operating groove that faces the opening at a predetermined position while the piston section moves up and down, and the sleeve engages with a stepped portion of the shaft body and moves only within a first predetermined range as the shaft body descends; the independent power generating device has a ferromagnetic element that is magnetically coupled to an electric coil and can swing, and an input member that inputs physical motion to swing the ferromagnetic element; the vertical width of the operating groove is determined based on the movement distance and swing angle of the sleeve and the thickness of the input member; and the input member that protrudes from the opening abuts against the upper or lower wall of the operating groove and is further pushed, thereby being operated.

2. A cylinder device comprising a piston section that moves up and down, a shaft body connected to the piston section, a sleeve that surrounds the shaft body, a cylindrical bore that surrounds the sleeve and has an opening midway up the length, and an independent power generating device, wherein the sleeve has an operating groove that faces the opening at a predetermined position while the piston section moves up and down, and the sleeve engages and moves with a first stepped section of the shaft body only in a first range at the end of the shaft body's descending process, and engages and moves with a second stepped section of the shaft body only in a second range at the end of the shaft body's ascending process, while the independent power generating device has a ferromagnetic element that is magnetically coupled to an electric coil and can swing, and an input member that inputs physical motion to swing the ferromagnetic element, the vertical width of the operating groove being determined based on the movement distance and swing angle of the sleeve and the thickness of the input member, and the input member protruding from the opening abuts against the upper or lower wall of the operating groove and is further pushed, thereby being operated.

3. A cylinder device comprising a piston section that moves up and down, a shaft body connected to the piston section, a sleeve that surrounds the shaft body, a cylindrical hole that surrounds the sleeve and has an opening midway up the length, and an independent power generating device, wherein the sleeve has a spirally inclined groove and a circumferential groove that are successively formed to face the opening, and the sleeve rotates as the shaft body moves up and down, while the independent power generating device has a ferromagnetic element that is magnetically coupled to an electric coil and can oscillate, and an input member that inputs physical motion to oscillate the ferromagnetic element, the vertical width of the operating groove being determined based on the movement distance and oscillation angle of the sleeve and the thickness of the input member, and the input member protruding from the opening abuts against the upper or lower wall of the operating groove and is further pushed, thereby being operated.

4. A self-sustaining power generating device comprising: a piston section that moves in the vertical direction; a shaft body having a tapered shaft section at the tip thereof connected to the piston section; a sleeve that surrounds the shaft body; a cylindrical hole that surrounds the sleeve and has an opening at its height; a grip member that abuts the sleeve from above and into which the tapered shaft section is inserted and that widens as the tapered shaft section descends; a cylindrical hole that surrounds the sleeve and has an opening at its height; and a self-sustaining power generating device, wherein the sleeve has an operation groove that faces the opening at a predetermined position while the piston section moves up and down, and the sleeve is pushed down and moved by the grip member as the grip member descends with the shaft body; meanwhile, the self-sustaining power generating device has a ferromagnetic element that is magnetically coupled to an electric coil and can swing; and an input member that inputs physical motion to swing the ferromagnetic element, and the vertical width of the operation groove is determined based on the movement distance and swing angle of the sleeve and the thickness of the input member, The cylinder device is characterized in that the input member protruding from the opening abuts against an upper wall or a lower wall of the operation groove and is further pushed to be operated.

5. A cylinder device comprising a piston section that moves up and down, a shaft body connected to the piston section, a cylindrical hole that surrounds the shaft body and has an opening midway up the length, and an independent power generating device, wherein an operation groove is provided in the shaft body so as to face the opening at a predetermined position while the piston section moves up and down, while the independent power generating device has a ferromagnetic element that is magnetically coupled to an electric coil and can swing, and an input member that inputs physical motion to swing the ferromagnetic element, the vertical width of the operation groove being determined based on the movement distance and swing angle of the piston section and the thickness of the input member, and the input member protruding from the opening abuts against the upper or lower wall of the operation groove and is further pushed, thereby being operated.

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