JP2007333122A - Hydraulic cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permanently secure a detecting function of an expanding/contracting state detecting means while allowing prescribed expanding/contracting operation. <P>SOLUTION: In this hydraulic cylinder where a magnet 4 of the expanding/contracting state detecting means detecting an expanding/contracting state that a rod body 2 frequently appears with respect to a cylinder body 1 and outputting a signal to the outside is received in a receiving portion A formed on the rod body 2 or the cylinder body 1, a holding member 62 of a holding means 6 introduced into the receiving portion A from the opening side of the receiving portion A connected with the rod body 2 or the cylinder body 1 forming the receiving portion A, and fixing the magnet 4 on a prescribed position is disposed in adjacent to the other end of the magnet 4 through a buffer member 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydraulic cylinder, and more particularly, to an improvement in a hydraulic cylinder that has an expansion / contraction state detection means and enables confirmation from a place away from the expansion / contraction state.

  For example, hydraulic cylinders that are used for seismic isolation in buildings are often housed in walls or placed under the floor in buildings, so that their expansion and contraction cannot be directly visually recognized. There are many cases.

  Therefore, the hydraulic cylinder has expansion / contraction state detection means, and the expansion / contraction of the hydraulic cylinder can be determined from an output signal from the expansion / contraction state detection means, for example, from a numerical value or chart displayed on a remote instrument panel. It is well known to check the state.

  Various proposals have conventionally been made as hydraulic cylinders having expansion / contraction state detection means. Among them, for example, Patent Document 1 discloses a hydraulic cylinder having expansion / contraction state detection means called a stroke sensor. Has been.

  That is, the hydraulic cylinder disclosed in Patent Document 1 is provided from a hydraulic supply / exhaust source disposed outside in a hydraulic chamber defined in the cylinder body by a piston portion of a rod body that is inserted in the cylinder body so as to be able to protrude and retract. The rod body protrudes from the cylinder body when the hydraulic pressure is supplied, and the rod body is immersed in the cylinder body when the hydraulic pressure in the hydraulic chamber is discharged to the hydraulic pressure supply / discharge source. It is supposed to be contracted.

  On the other hand, this hydraulic cylinder has an expansion / contraction state detection means called a stroke sensor that detects the expansion / contraction state where the rod body appears and disappears with respect to the cylinder body and outputs the detection result as a signal to the outside. It is said to have.

  The expansion / contraction state detecting means includes a sensor rod having a proximal end portion held by the cylinder body and a distal end side of which is located in a long hole opened in the shaft core portion of the rod body. It is supposed that the piston part of the rod body has an annular or cylindrical magnet that is movably inserted into the rod body.

  At this time, the sensor rod is formed, for example, in a configuration having a magnetostrictive wire and a protective cylinder covering the outer periphery of the magnetostrictive wire, and the main body portion which is the base end portion generates a magnetic field on the outer periphery of the magnetostrictive wire so that a current pulse is applied to the magnetostrictive wire. It is configured to output an analog or digital electrical signal corresponding to the time from when the vibration pulse generated at the portion facing the magnet of the magnetostrictive line returns due to the Wiedemann effect.

Therefore, according to the hydraulic cylinder disclosed in Patent Document 1, an output signal from the expansion / contraction state detection means is input to, for example, a control device at a remote location, whereby the instrument included in the control device is provided. The expansion / contraction state of the hydraulic cylinder can be easily confirmed from the numerical values and charts displayed on the panel.
JP-A-11-190308 (paragraphs 0004 to 0007, FIG. 3 in the specification)

  However, in the hydraulic cylinder disclosed in Patent Document 1 described above, there is no problem with the realization of the expansion / contraction operation that is the original operation, but there may be a slight problem with the detection function of the expansion / contraction state detection means. May be pointed out.

  That is, in the expansion / contraction state detecting means of the hydraulic cylinder described above, the annular or cylindrical magnet is disposed in the axial center portion of the piston portion of the rod body that defines the hydraulic chamber in the hydraulic cylinder. It is supposed to be done.

  At this time, the shaft portion of the piston portion is formed with a housing portion whose opening is an inner concave portion facing the hydraulic chamber, and the nonmagnetic material disposed so as to be laid on the bottom portion of the housing portion. A magnet is disposed so as to be stacked on the sheet member, and the magnet is disposed by the retaining means.

  Incidentally, the holding means includes a holding member that is also made of a non-magnetic material and is formed in a hat shape that covers the magnet from the outside, and a screw member that screws the holding member to the piston portion, and the screw member is attached to the bottom of the housing portion. The magnet is fixed by fixing the holding member by screwing.

  Therefore, in the measure to fix the magnet sandwiched between the sheet member to a predetermined position by the screw member in the holding means, it is necessary to precisely manage the tightening torque for the screw member. If the tightening torque for the screw member is excessive or insufficient, the magnet may be damaged or the magnet may not be fixed at a predetermined position.

  When the magnet is damaged and drops off, etc., the predetermined detection function of the expansion / contraction state detection unit is not performed, and when the magnet is not fixed at a predetermined position, the detection by the expansion / contraction state detection unit is performed. As a result, an error occurs, and it becomes difficult to confirm the exact expansion / contraction state of the hydraulic cylinder.

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is to allow a predetermined expansion / contraction operation as well as a detection function of the expansion / contraction state detection means permanently. It is an object of the present invention to provide a hydraulic cylinder that can be guaranteed and is optimally expected to improve its versatility.

  In order to achieve the above-described object, the structure of the hydraulic cylinder according to the present invention basically includes a hydraulic chamber defined in the cylinder body by a rod body inserted so as to be able to appear and retract in the cylinder body, outside the cylinder body. By expanding and contracting by supplying and discharging hydraulic pressure from the installed hydraulic supply and discharge source, the rod body protrudes and retracts with respect to the cylinder body, and the expansion and contraction state in which the rod body protrudes and retracts from this cylinder body is detected. In a hydraulic cylinder having an expansion / contraction state detection means for outputting a signal to the outside, the expansion / contraction state detection means is inserted through a sensor rod held by the cylinder body or rod body, and the sensor rod is movably inserted into the shaft core portion. A cylinder body that is formed in an annular or cylindrical shape, and the magnet in the expansion / contraction state detecting means is opposite to the cylinder body or rod body that holds the sensor rod It is housed in a housing part formed on a rod body or cylinder body made of a material, and is accommodated by a holding means connected to the rod body or cylinder body which is introduced into the housing part from the opening side of the housing part and forms the housing part The sheet member is disposed between the one end of the magnet in the axial direction along the axial direction of the sensor rod in the magnet and the bottom of the housing portion facing the one end, and the end opposite to the one end of the magnet It is assumed that the abutting portion of the holding member in the holding means facing the other end is adjacent to the other end of the magnet while having a buffer member.

  Therefore, in the present invention, the annular or cylindrical magnet that constitutes the expansion / contraction state detecting means together with the sensor rod is accommodated in the accommodating portion, and one end of the magnet and the bottom of the accommodating portion While the sheet member is disposed between the holding member, the holding member in the holding unit that is introduced from the opening side of the storage unit into the storage unit and fixes the magnet in the storage unit faces the other end of the magnet. Since the holding member in the holding means exceeds the proper size, it is connected to the rod body or the cylinder body that forms the accommodating portion by an excessive external force. However, this excessive external force is absorbed by the buffer member and is alleviated, so that it is possible to avoid the occurrence of defects such as cracks in the magnet due to the excessive external force acting.

  As long as the external force possessed by the holding means is not excessively reduced, the magnet is not displaced at a predetermined position by the retaining force that is the external force that the buffer member has, so that the magnet is fixed at the fixing position. An error is not generated in the resulting detection result.

  Incidentally, the shock-absorbing member is formed, for example, in a ring shape with a rubber material or a synthetic resin material. Specifically, it is economical to use an O-ring. It is good also as being integrally connected to the predetermined position in the holding member which comprises these by vapor deposition or utilization of an adhesive material.

  The present invention will be described below based on the illustrated embodiment. The hydraulic cylinder according to the present invention is basically the hydraulic pressure disclosed in Patent Document 1 described above except for the configuration of the expansion / contraction state detecting means. It is formed to have the same configuration as the cylinder.

  That is, as shown in FIG. 1, a hydraulic cylinder according to the present invention includes a cylinder body 1 that is one side member, and a rod that is an opposite side member to the cylinder body 1 and is inserted into the cylinder body 1 so as to be able to appear and retract. And a body 2.

  And in this hydraulic cylinder, it is defined in the cylinder body 1 by the insertion of the rod body 2 into the cylinder body 1, that is, by the piston portion 2a in the rod body 2 inserted into the cylinder body 1. The hydraulic chamber R is connected to a hydraulic pressure supply / exhaust source (not shown, only indicated by the symbol P) provided outside the cylinder body 1.

  Therefore, in this hydraulic cylinder, when the hydraulic chamber R is expanded by receiving the hydraulic pressure supplied from the hydraulic supply / discharge source P, it is said that the piston portion 2a moves right in the cylinder body 1 in the drawing. The rod body 2 slides in the extending direction, and at this time, the rod body 2 is extended so as to protrude from the cylinder body 1.

  In this hydraulic cylinder, when the hydraulic pressure in the hydraulic chamber R is discharged to the hydraulic supply / discharge source P and the hydraulic chamber R contracts, the piston portion 2a moves left in the cylinder body 1 in the drawing. In other words, the rod body 2 slides in the contraction direction, and at this time, the rod body 2 is contracted so as to be immersed in the cylinder body 1.

  On the other hand, this hydraulic cylinder has expansion / contraction state detection means that is sometimes referred to as a so-called stroke sensor that detects an expansion / contraction state in which the rod body 2 protrudes and retracts relative to the cylinder body 1 and outputs a signal to the outside. It is supposed to be done.

  And this expansion-contraction state detection means is formed in the cylinder shape in which the sensor rod 3 hold | maintained at the cylinder body 1 which is one side member, and this sensor rod 3 is movably inserted in an axial center part in the figure. And a magnet 4 held by a rod body 2 which is a member opposite to the cylinder body 1.

  At this time, although the magnet 4 is formed in a cylindrical shape in the drawing, the magnet 4 is formed in a ring shape instead of being formed in a cylindrical shape as long as a predetermined magnetic field can be formed in the shaft core portion. Of course, it may be formed, and when it is formed in an annular shape, it is a matter of course that a plurality may be laminated to form a cylindrical shape.

  By the way, the sensor rod 3 constituting the expansion / contraction state detecting means is shown in FIG. 1, while the base end side that is the left end side in FIG. 1 is held by the cylinder body 1, and the distal end side that is the right side in FIG. It is supposed that it is made to reside in the long hole 2b of the opening at the axial center part of No.2.

  At this time, the sensor rod 3 is formed, for example, in a configuration having a magnetostrictive wire (not shown) and a protective cylinder 31 covering the outer periphery of the magnetostrictive wire, and the main body 3a as the base end generates a magnetic field on the outer periphery of the magnetostrictive wire. It is configured to output an analog or digital electric signal according to the time from when a current pulse is applied to the magnetostrictive wire to when a vibration pulse generated at the portion facing the magnet of the magnetostrictive wire returns due to the Wiedemann effect. It is said.

  In the sensor rod 3, as shown in the drawing, the sensor rod 3 is made of a non-magnetic material and extends to the shaft core portion of the guide cylinder 32 held by the cylinder body 1, and the guide cylinder 32 is extended from the outside. The magnet 4 is disposed so as to surround it, and an alignment guide member 33 is disposed between the inner periphery of the guide tube 32 and the outer periphery of the protection tube 31.

  Further, as shown in the figure, it is assumed that a guide member 34 for alignment is provided on the outer periphery of the distal end portion 32a which is the right end portion in FIG. 1 of the guide tube 32, and the outer periphery of the guide member 34 for alignment is It is assumed that it slides on the inner periphery of the long hole 2b.

  In addition, the sensor rod 3 is shown in the drawing in which a rib portion 3b for connecting the main body portion 3a and a so-called rod portion present in the cylinder body 1 is a part of the bottom end portion 1a of the cylinder body 1. The cylinder body 1 is held by being screwed to the shaft core portion of the bottom cap member 11 that forms the shape.

  Therefore, in the illustrated expansion / contraction state detecting means, the sensor rod 3 is accommodated in the guide tube 32 while having the alignment guide member 33 on the outer periphery. Therefore, the bending and deflection within the 32 are prevented, and it is possible to detect a stretched state without so-called error.

  In the expansion / contraction state detecting means shown in the figure, the guide cylinder 32 is also inserted into the long hole 2b opened in the shaft core portion of the rod body 2 while having the alignment guide member 34 on the outer periphery. Therefore, the deflection in the elongated hole 2b of the distal end portion 32a in the guide tube 32 is prevented, and as a result, the expansion / contraction state can be detected without error by the expansion / contraction state detection means.

  On the other hand, the magnet 4 described above is accommodated in the accommodating portion A formed of an inner concave portion formed in the rod body 2 that is a member opposite to the cylinder body 1 that holds the sensor rod 3. Yes.

  At this time, as shown in an enlarged view in FIG. 2, the magnet 4 has one end in the axial direction along the axial direction which is the left-right direction in the drawing of the sensor rod 3, that is, the right end in the drawing and the right end as the one end. The rod member 2 that is introduced into the housing portion A from the opening side on the left side of the housing portion A in the drawing while the sheet member 5 is disposed between the bottom portion 2c of the housing portion A to be formed and forms the housing portion A. It is assumed that it is fixed in the storage portion A by the holding means 6 to be connected.

  The sheet member 5 is made of a non-magnetic material, but in the illustrated case, the sheet member 5 is formed in an annular shape that matches the shape of the bottom portion 2c of the housing portion A. At this time, the thickness of the sheet member 5 penetrates the outer peripheral side. Thus, the hole 5a is opened, and the screw member 61 in the holding means 6 described later is allowed to pass through the hole 5a.

  In addition, about this sheet | seat member 5, this may be adhere | attached on the magnet 4 by utilization of an adhesive material etc., and it may be united with the magnet 4, and in this case, the magnet 4 and the sheet | seat member in the accommodating part A are sufficient. Therefore, it is possible to make the work for housing 5 as a single unit, so that the so-called assemblability is improved.

  By the way, the holding means 6 fixes the above-described magnet 4 to the accommodating portion A at a predetermined position, and is formed of a nonmagnetic material and having a predetermined mechanical strength like the above-described sheet member 5. ing.

  2, the holding means 6 includes a screw member 61 that is screwed into the bottom 2c of the housing portion A and a holding member 62 that is fixed to the bottom 2c side of the housing portion A with the screw member 61. The holding member 62 is introduced into the accommodating portion A from the opening side on the left side of the accommodating portion A in FIG. 2 and sandwiches the magnet 4 between the holding member 62 and the sheet member 5.

  On the other hand, in the holding means 6 shown in FIG. 3, the thread 62a formed on the outer periphery of the holding member 62 is screwed to the wall 2d of the housing A to be connected to the rod body 2 forming the housing A. It is supposed to be done.

  Therefore, in the case of the embodiment shown in FIG. 3, the screw member 61 (see FIG. 2) is unnecessary, which is advantageous in that the number of parts can be reduced accordingly.

  As described above, in the expansion / contraction state detecting means according to the present invention, since the magnet 4 seated on the sheet member 5 is fixed in the accommodating portion A by the holding means 6, the holding means 6 is so-called excessive. When the magnet 4 is fixed with an external force, an excessive external force acts on the magnet 4, and as a result, there is a risk of causing problems such as cracks in the magnet 4.

  Further, when the external force possessed by the holding means 6 is too small, there is a concern that the magnet 4 is not fixed at a predetermined position and is displaced at a predetermined position.

  Therefore, in the present invention, as shown in FIGS. 2 and 3, the other end which is the left end in FIGS. 2 and 3 which is the opposite end of one end of the magnet 4 and the holding means 6 which opposes the other end The buffer member 7 is held between the member 62 and the contact portion 62b.

  The buffer member 7 is formed, for example, in a ring shape with a rubber material or a synthetic resin material. Specifically, it is economical to use an O-ring. The holding member 62 constituting the holding means 6 is housed in an annular groove 62c formed in the abutting portion 62b at a predetermined position.

  At this time, the buffer member 7 may be integrally connected to the contact portion 62b, that is, to the holding member 62, so that the buffer member 7 is fixed in the annular groove 62c by vapor deposition or using an adhesive. .

  Therefore, in the case of having the buffer member 7 as described above, when the holding means 6, that is, the holding member 62 presses the magnet 4 against the sheet member 5, the buffer is interposed between the holding member 62 and the magnet 4. Since the member 7 is provided, the so-called contact of the holding member 62, that is, the holding means 6 with respect to the magnet 4 can be reduced, and it is possible to prevent the magnet 4 from being cracked.

  In addition, if the holding member 62 has a small force when pressing the magnet 4 against the sheet member 5, and there is a concern that the magnet 4 may be slightly displaced at the position where it is disposed, The displacement of the magnet 4 can be prevented by the elastic force of the buffer member 7, and no error is generated in the detection result by the expansion / contraction state detecting means due to the fixing position of the magnet 4.

  In the above description, the case where the hydraulic cylinder according to the present invention is formed in a single rod type has been described as an example. However, when the hydraulic cylinder is used for seismic isolation in a building, for example, both rods are used. Of course, it may be formed into a mold, and in that case, the realization of the present invention is not hindered and the function and effect are not different.

It is sectional drawing which shows the hydraulic cylinder by this invention. It is a fragmentary sectional view which expands and shows the principal part of the expansion-contraction state detection means in the hydraulic cylinder of FIG. It is a figure which shows the principal part of the expansion-contraction state detection means by other embodiment similarly to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder body 2 Rod body 2c Bottom part 2d Wall part 3 Sensor rod which comprises an expansion-contraction state detection means 4 Magnet which comprises an expansion-contraction state detection means 5 Sheet member 6 Holding means 6a Screw 7 O ring member 61 Screw member P Hydraulic supply / discharge Source R Hydraulic room

Claims (4)

A hydraulic chamber defined in the cylinder body by a rod body inserted so as to be able to appear and retract in the cylinder body is expanded and contracted by supply and discharge of hydraulic pressure by a hydraulic supply and discharge source disposed outside the cylinder body. In a hydraulic cylinder having an expansion / contraction state detection means for detecting the expansion / contraction state in which the rod body protrudes and retracts with respect to the cylinder body and outputs a signal to the outside by extending and retracting the rod body. The means has a sensor rod held by the cylinder body or the rod body, and an annular or cylindrical magnet that allows the sensor rod to be movably inserted into the shaft core, and the magnet in the expansion / contraction state detecting means is the sensor rod The cylinder body or rod body that holds the rod is housed in the housing part formed on the rod body or cylinder body that is the opposite member, and the housing part One end in the axial direction along the axial direction of the sensor rod in the magnet and the one end thereof are fixed by the holding means connected to the rod body or cylinder body that is introduced into the housing portion from the mouth side and is connected to the cylinder body. A sheet member is disposed between the housing portion and the bottom portion of the housing portion facing each other, and the contact portion of the holding member in the holding means facing the other end opposite to the one end of the magnet has a buffer member. A hydraulic cylinder characterized by being adjacent to the other end of the magnet. The hydraulic cylinder according to claim 1, wherein the buffer member is formed in an annular shape while being made of a rubber material or a synthetic resin material. 2. The hydraulic cylinder according to claim 1, wherein the holding member is connected to a rod body or a cylinder body that forms the housing portion by screwing the screw member into the bottom portion of the housing portion. The hydraulic cylinder according to claim 1, wherein the holding member is connected to a rod body or a cylinder body that forms the accommodating portion by screwing the retaining member to the wall portion of the accommodating portion.

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