JP2019007601A - Cylinder device - Google Patents

Abstract

To suppress deterioration of an electroviscous fluid by suppressing generation of sparks from an electric field imparting body toward the inside of a reservoir chamber.SOLUTION: In an intermediate cylinder 17 for forming a reservoir chamber A between itself and an external cylinder 3, a high voltage is applied via a high voltage driver from the outside (battery 21) of a damper 1 via an electric field imparting body 22. Spark suppression members 23, 24 are provided between the external cylinder 3 and the intermediate cylinder 17. The spark suppression members 23, 24 are provided in positions separated in an axis direction of the reservoir chamber A by sandwiching the electric field imparting body 22 respectively. The spark suppression members 23, 24 suppress generation of sparks from an electrode pin 22C of the electric field imparting body 22 toward the inside of the reservoir chamber A in directions A1, A2 indicated by arrows.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cylinder device suitably used for buffering vibrations of, for example, automobiles and railway vehicles.

  Generally, in a vehicle such as an automobile, a cylinder device represented by a hydraulic shock absorber is provided between a vehicle body (on a spring) side and each wheel (under a spring) side. In this type of cylinder device, a configuration in which the generated damping force is variably controlled by applying an electric field by a high voltage in a state where an electrorheological fluid is sealed in the cylinder is known (for example, a patent) Reference 1).

German Patent Application Publication No. 10201303488

  By the way, in the prior art, an electric field applying body is provided in contact with the electrode serving as the intermediate cylinder from the outside in the radial direction in the reservoir chamber of the cylinder device (buffer), and a high voltage is applied from the electric field applying body to the electrode (intermediate cylinder). It is set as the structure which gives. However, in the reservoir chamber of the shock absorber, a spark due to a discharge phenomenon may occur from the electric field applying body toward the electrorheological fluid in the reservoir chamber, which causes deterioration of the electrorheological fluid.

  An object of the present invention is to provide a cylinder device capable of suppressing the occurrence of sparks from the electric field applying body into the reservoir chamber and suppressing the deterioration of the electrorheological fluid.

  In order to solve the above-described problems, a cylinder device according to the present invention is provided with an inner cylinder into which an electrorheological fluid whose fluid viscosity changes due to an electric field is inserted, and a rod inserted therein, and an outer cylinder. An outer cylinder, an intermediate cylinder provided between the inner cylinder and the outer cylinder, and forming a passage through which the electrorheological fluid flows between the inner cylinder and the intermediate cylinder and the outer cylinder A reservoir chamber in which the electrorheological fluid and the working gas are sealed, a rod guide that is provided to close one end of the inner cylinder and the outer cylinder, and supports the rod in a telescopic manner; In order to apply an electric field to the electrorheological fluid in the passage between the cylinder and the intermediate cylinder, the electric cylinder protrudes from the outside of the outer cylinder toward the outer peripheral surface of the intermediate cylinder, and the intermediate cylinder is higher than the inner cylinder. An electric field applying body set to a potential, and the outer cylinder; Between between cylinder, spark suppression member suppressing the electric field imparting body of the spark is generated toward the reservoir chamber is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that a spark generate | occur | produces toward an inside of a reservoir | reserver chamber from an electric field application body, can suppress deterioration of an electrorheological fluid, and can improve durability and lifetime of an apparatus. .

It is a longitudinal cross-sectional view which shows the shock absorber as a cylinder apparatus by 1st Embodiment. It is principal part sectional drawing which expands and shows the electric field provision body in FIG. 1, a spark suppression member, etc. FIG. It is sectional drawing which expands and shows the spark suppression member in FIG. It is a perspective view which expands and shows the spark suppression member in FIG. It is principal part sectional drawing which expands and shows the electric field provision body by 2nd Embodiment, a spark suppression member, etc. FIG.

  Hereinafter, a case where the cylinder device according to the embodiment of the present invention is applied to a shock absorber provided in a vehicle such as a four-wheel automobile will be described as an example with reference to the accompanying drawings.

  1 to 4 show a first embodiment. In FIG. 1, a shock absorber 1 as a cylinder device is a damping force adjusting hydraulic shock absorber (semi-active damper) using a functional fluid (ie, electrorheological fluid) made of liquid as a working fluid 20 enclosed inside. It is configured as. The shock absorber 1 constitutes a suspension device for a vehicle together with a suspension spring (not shown) made of, for example, a coil spring. In the following description, one end side of the shock absorber 1 in the axial direction is referred to as an “upper end” side, and the other end side in the axial direction is referred to as a “lower end” side.

  The shock absorber 1 includes an inner cylinder 2, an outer cylinder 3, a piston 5, a piston rod 8, an intermediate cylinder 17, and the like. The inner cylinder 2 is formed as a cylindrical cylinder extending in the axial direction, and a working fluid 20 (that is, an electrorheological fluid) described later is enclosed therein. A piston rod 8 to be described later is inserted into the inner cylinder 2, and the outer cylinder 3 is provided coaxially on the radially outer side of the inner cylinder 2.

  The outer cylinder 3 forms an outer shell of the shock absorber 1 and is formed as a cylindrical body. The outer cylinder 3 has a closed end whose lower end is closed by a bottom cap 4 using welding means or the like. The bottom cap 4 constitutes a base member together with a valve body 13 of the bottom valve 12 described later. The upper end side of the outer cylinder 3 serves as an opening end, and a caulking portion 3A is formed at the opening end side by bending inward in the radial direction. The caulking portion 3A holds the outer peripheral side of the annular plate 11A of the seal member 11 in a retaining state. Further, the outer cylinder 3 is formed with a mounting hole 3B to which a sealing cylinder 22A of the electric field applying body 22 described later is attached as a radial lateral hole (through hole).

  On the other hand, the inner cylinder 2 is provided coaxially with the outer cylinder 3 in the outer cylinder 3. The lower end side of the inner cylinder 2 is fitted and attached to the valve body 13 of the bottom valve 12, and the upper end side is fitted and attached to the rod guide 9. The inner cylinder 2 is formed with a plurality (for example, 4 to 8) of oil holes 2 </ b> A that are always in communication with a passage 18 to be described later and spaced apart in the circumferential direction as radial lateral holes. The rod side oil chamber B in the inner cylinder 2 communicates with the passage 18 through the oil hole 2A.

  The inner cylinder 2 constitutes a cylinder together with the outer cylinder 3, and a working fluid 20 is sealed in the cylinder. Here, in the embodiment, an electrorheological fluid (ERF) made of a liquid is used as the working fluid 20 filled (enclosed) in the cylinders (the inner cylinder 2 and the outer cylinder 3). In each figure, the sealed working fluid 20 is colorless and transparent.

  The electrorheological fluid is a kind of functional fluid whose properties change due to an external stimulus, and the electrorheological fluid is a fluid whose viscosity (properties) changes as the electric field (voltage) increases or decreases. That is, the electrorheological fluid changes its flow resistance (damping force) according to the applied voltage (electric field strength). The electrorheological fluid is composed of, for example, a base oil (base oil) made of silicon oil or the like, and particles (fine particles) mixed (dispersed) in the base oil to change the viscosity according to a change in electric field. Yes. The shock absorber 1 is configured to control (adjust) the generated damping force by generating a potential difference in a passage 18 to be described later and variably controlling the viscosity of the electrorheological fluid passing through the passage 18.

  An annular reservoir chamber A is formed between the inner cylinder 2 and the outer cylinder 3. In the reservoir chamber A, a gas serving as a working gas is sealed together with the liquid working fluid 20. This gas may be atmospheric pressure air or a compressed gas such as nitrogen gas. The gas in the reservoir chamber A is compressed to compensate for the entry volume of the piston rod 8 when the piston rod 8 is contracted (contraction stroke).

  The piston 5 is slidably inserted into the inner cylinder 2. The piston 5 defines the inside of the inner cylinder 2 into a rod side oil chamber B and a bottom side oil chamber C. The piston 5 is formed with a plurality of oil passages 5A and 5B that allow the rod-side oil chamber B and the bottom-side oil chamber C to communicate with each other in the circumferential direction. Here, the shock absorber 1 according to the embodiment has a uniflow structure. For this reason, the working fluid 20 in the inner cylinder 2 is directed from the rod side oil chamber B (that is, the oil hole 2A of the inner cylinder 2) toward the passage 18 in both the contraction stroke and the extension stroke of the piston rod 8. It always circulates in one direction (that is, the direction of arrow F indicated by a two-dot chain line in FIG. 1).

  In order to realize such a uniflow structure, the piston 5 is opened on the upper end surface of the piston 5 when, for example, the piston 5 is slid downward in the inner cylinder 2 in the reduction stroke (contraction stroke) of the piston rod 8. In other cases, a non-return check valve 6 is provided that closes. The contraction-side check valve 6 allows the liquid (working fluid 20) in the bottom side oil chamber C to flow in each oil passage 5A toward the rod side oil chamber B, and the liquid flows in the opposite direction. Stop flowing.

  On the lower end surface of the piston 5, for example, an extension-side disc valve 7 is provided. When the piston 5 slides upward in the inner cylinder 2 during the extension stroke (extension stroke) of the piston rod 8, the pressure in the rod-side oil chamber B exceeds the relief set pressure. And the pressure at this time is relieved to the bottom side oil chamber C via each oil passage 5B.

  The piston rod 8 as a rod extends in the inner cylinder 2 in the axial direction (the same direction as the central axis of the inner cylinder 2 and the outer cylinder 3 and in the upper and lower directions in FIG. 1). That is, the lower end side of the piston rod 8 is connected (fixed) to the piston 5 in the inner cylinder 2, and the upper end side extends to the outside of the inner cylinder 2 and the outer cylinder 3 serving as cylinders. In this case, the piston 5 is fixed (fixed) to the lower end side of the piston rod 8 using a nut 8A or the like. On the other hand, the upper end side of the piston rod 8 protrudes outside through the rod guide 9. The lower end of the piston rod 8 may be further extended so as to protrude outward from the bottom portion (for example, the bottom cap 4) side, so-called double rods may be used.

  A stepped cylindrical rod guide 9 is fitted and provided on the upper end side (one end side) of the inner cylinder 2 and the outer cylinder 3 so as to close the upper end sides of the inner cylinder 2 and the outer cylinder 3. . The rod guide 9 supports the piston rod 8 and is formed as a cylindrical body having a predetermined shape, for example, by subjecting a metal material, a hard resin material, or the like to molding or cutting. The rod guide 9 positions the upper part of the inner cylinder 2 and the upper part of the intermediate cylinder 17 described later in the center of the outer cylinder 3. At the same time, the rod guide 9 guides (guides) the piston rod 8 so as to be slidable in the axial direction on the inner peripheral side thereof.

  Here, the rod guide 9 is positioned on the upper side and is inserted into the inner peripheral side of the outer cylinder 3. The rod guide 9 is positioned on the inner peripheral side of the outer cylinder 3. The rod guide 9 is positioned on the inner side of the inner cylinder 2. It is formed in a stepped cylindrical shape by a short cylindrical small-diameter portion 9B that is fitted on the peripheral side. On the inner peripheral side of the small-diameter portion 9B of the rod guide 9, a guide portion 9C that guides the piston rod 8 so as to be slidable in the axial direction is provided. The guide portion 9C is formed, for example, by applying a tetrafluoroethylene coating on the inner peripheral surface of a metal cylinder.

  On the other hand, an annular holding member 10 is fitted and attached between the large diameter portion 9A and the small diameter portion 9B on the outer peripheral side of the rod guide 9. The holding member 10 holds the upper end side of an intermediate cylinder 17 to be described later in a state of being positioned in the axial direction. The holding member 10 is formed of, for example, an electrically insulating material and keeps the inner cylinder 2 and the rod guide 9 and the intermediate cylinder 17 in an electrically insulated state.

  An annular seal member 11 is provided between the large diameter portion 9 </ b> A of the rod guide 9 and the caulking portion 3 </ b> A of the outer cylinder 3. The seal member 11 is made of a metallic annular plate body 11A provided with a hole through which the piston rod 8 is inserted at the center, and an elastic material such as rubber fixed to the annular plate body 11A by means such as baking. The elastic body 11B is included. The seal member 11 seals (seal) between the piston rod 8 in a liquid-tight and air-tight manner when the inner circumference of the elastic body 11B is in sliding contact with the outer circumference of the piston rod 8.

  A bottom valve 12 is provided on the lower end side (the other end side) of the inner cylinder 2 so as to be positioned between the inner cylinder 2 and the bottom cap 4. The bottom valve 12 includes a valve body 13, an extension side check valve 15, and a disc valve 16. The valve body 13 defines a reservoir chamber A and a bottom oil chamber C between the bottom cap 4 and the inner cylinder 2. The valve body 13 is formed with oil passages 13A and 13B that allow the reservoir chamber A and the bottom oil chamber C to communicate with each other at intervals in the circumferential direction.

  A step portion 13C is formed on the outer peripheral side of the valve body 13, and the lower end inner peripheral side of the inner cylinder 2 is fitted and fixed to the step portion 13C. Further, an annular holding member 14 is fitted and attached to the outer peripheral side of the inner cylinder 2 at the step portion 13C. The holding member 14 holds the lower end side of an intermediate cylinder 17 described later in a state of being positioned in the axial direction. The holding member 14 is formed of, for example, an electrically insulating material, and keeps the inner cylinder 2 and the valve body 13 and the intermediate cylinder 17 in an electrically insulated state. The holding member 14 is formed with a plurality of oil passages 14 </ b> A that allow passages 18 to be described later to communicate with the reservoir chamber A.

  The extension side check valve 15 is provided, for example, on the upper surface side of the valve body 13. The extension-side check valve 15 opens when the piston 5 slides upward in the extension stroke of the piston rod 8, and closes at other times. The extension-side check valve 15 allows the liquid (working fluid 20) in the reservoir chamber A to flow in each oil passage 13A toward the bottom-side oil chamber C, and the liquid flows in the opposite direction. To prevent.

  The reduction-side disc valve 16 is provided, for example, on the lower surface side of the valve body 13. The disc valve 16 on the reduction side opens when the pressure in the bottom side oil chamber C exceeds the relief set pressure when the piston 5 slides downward in the reduction stroke of the piston rod 8, and the pressure at this time Is relieved to the reservoir chamber A side through each oil passage 13B.

  Between the outer cylinder 3 and the inner cylinder 2, an intermediate cylinder 17 made of a pressure tube extending in the axial direction is provided. The intermediate cylinder 17 is formed using a conductive material, and constitutes a cylindrical electrode to which a high voltage (electric field) is applied from an electric field applying body 22 described later. The intermediate cylinder 17 forms a passage 18 in which the working fluid 20 flows by the forward and backward movement of the piston rod 8 from the upper end side in the axial direction toward the lower end side between the intermediate cylinder 17 and the inner cylinder 2.

  That is, the intermediate cylinder 17 is attached to the outer peripheral side of the inner cylinder 2 via the holding members 10 and 14. The holding members 10 and 14 are spaced apart in the axial direction (vertical direction) on the outer peripheral side of the inner cylinder 2. In this case, the upper end side of the intermediate cylinder 17 cannot be rotated relative to the outer cylinder 3 via the holding member 10 and the rod guide 9. The lower end side of the intermediate cylinder 17 cannot be rotated relative to the outer cylinder 3 via the holding member 14, the valve body 13 and the bottom cap 4. The intermediate cylinder 17 surrounds the outer circumference side of the inner cylinder 2 over the entire circumference, so that an annular flow path is formed inside the intermediate cylinder 17, that is, between the inner circumference side of the intermediate cylinder 17 and the outer circumference side of the inner cylinder 2. That is, a passage 18 through which the working fluid 20 flows is formed. Further, on the outer diameter side of the intermediate cylinder 17, an electrode pin 22 </ b> C of an electric field applying body 22 described later is attached at a position facing the attachment hole 3 </ b> B of the outer cylinder 3 in the radial direction.

  The passage 18 is always in communication with the rod-side oil chamber B through an oil hole 2A formed as a radial lateral hole in the inner cylinder 2. In the shock absorber 1, the working fluid 20 flows into the passage 18 from the rod side oil chamber B through the oil hole 2 </ b> A in both the contraction stroke and the extension stroke of the piston 5. The working fluid 20 that has flowed into the passage 18 is moved upward and backward in the inner cylinder 2 (that is, while the contraction stroke and the extension stroke are repeated). It flows toward the lower end side. That is, in FIG. 1, the flow direction of the working fluid 20 is indicated by an arrow F.

  The working fluid 20 that has flowed into the passage 18 flows out from the lower end side of the intermediate cylinder 17 to the reservoir chamber A through the oil passage 14 </ b> A of the holding member 14. At this time, the pressure of the working fluid 20 is highest on the upstream side of the passage 18 (that is, on the oil hole 2A side), and gradually decreases because the passage (passage) resistance is received while flowing through the passage 18. For this reason, the working fluid 20 in the passage 18 has the lowest pressure when it flows through the downstream side of the passage 18 (that is, the oil passage 14A of the holding member 14).

  A partition wall member 19 is provided between the outer periphery of the inner cylinder 2 and the inner periphery of the intermediate cylinder 17 to partition the passage 18 through which the working fluid 20 flows (guides the flow of the working fluid 20). The partition member 19 is attached to the outer peripheral surface of the inner cylinder 2 and the inner peripheral surface of the intermediate cylinder 17 so as not to rotate relative to each other. The partition wall member 19 is a flow path forming member that guides the working fluid 20 not only in the axial direction but also in the circumferential direction between the inner cylinder 2 and the intermediate cylinder 17. Thereby, the channel | path 18 which the working fluid 20 distribute | circulates can be made into the spiral or meandering 1 or several channel | path (flow path) which has the part extended in the circumferential direction. In this case, the entire length of the passage 18 (the length of the flow path from the oil hole 2A to the oil passage 14A) can be made longer than the passage extending linearly in the axial direction.

  The passage 18 provides resistance to the working fluid 20 (that is, electrorheological fluid) that flows through the sliding of the piston 5 in the outer cylinder 3 and the inner cylinder 2. For this reason, the intermediate cylinder 17 is connected to the positive electrode of the battery 21 serving as a power source via, for example, a high voltage driver (not shown) that generates a high voltage and an electric field applying body 22 described later. The battery 21 constitutes a voltage supply unit (electric field supply unit) together with the high voltage driver, and the intermediate cylinder 17 has electrodes (electrified) for applying an electric field to the working fluid 20 (that is, electrorheological fluid) flowing in the passage 18. Load). Here, both end sides of the intermediate cylinder 17 are electrically insulated from the rod guide 9 and the valve body 13 (bottom cap 4) via electrically insulating holding members 10 and 14. On the other hand, the inner cylinder 2 is connected to a negative electrode (ground) via a rod guide 9, a bottom valve 12 (valve body 13), a bottom cap 4, an outer cylinder 3, a high voltage driver, and the like.

  The high voltage driver boosts the DC voltage output from the battery 21 based on a command signal (high voltage command) output from a controller (not shown) for variably adjusting the damping force of the shock absorber 1. Then, it is supplied (output) to the intermediate cylinder 17. Thereby, a potential difference corresponding to the high voltage applied to the intermediate cylinder 17 is generated between the inner cylinder 2 and the intermediate cylinder 17, in other words, in the passage 18, and the working fluid 20, which is an electrorheological fluid, is generated. Viscosity changes. In this case, the shock absorber 1 generates a hard damping characteristic (hard characteristic) and a soft characteristic (soft characteristic) according to the high voltage applied to the intermediate cylinder 17 (damping force characteristic). (Soft characteristics) can be continuously adjusted. The shock absorber 1 may be capable of adjusting the damping force characteristics in two stages or a plurality of stages without being continuous. In this embodiment, the voltage boosted by the high voltage driver is a DC voltage, but may be an AC voltage.

  As shown in FIG. 2, the electric field applying body 22 includes a sealing cylinder 22A, an insulating member 22B, and electrode pins 22C. The sealing cylinder 22A is formed in a stepped cylinder shape with, for example, a conductive metal material, and is fixed so as to seal the mounting hole 3B of the outer cylinder 3 from the outside. The sealing cylinder 22A is attached in a gas- and liquid-tight manner to the mounting hole 3B of the outer cylinder 3 by welding, for example, over the entire circumference in a state of being in contact with the periphery of the mounting hole 3B of the outer cylinder 3. Yes.

  The insulating member 22B is fixedly provided between the sealing cylinder 22A and the electrode pin 22C. The insulating member 22B is a member that covers the electrode pin 22C from the outside and electrically insulates between the sealing cylinder 22A and the electrode pin 22C. The electrode pin 22 </ b> C is an electric field applying unit that applies a high voltage (electric field) from the high voltage driver and the battery 21 to the intermediate cylinder 17. The electrode pin 22C is a pin-shaped member that is formed in a stepped columnar shape using a conductive material and extends in the axial direction. The electrode pin 22 </ b> C has a hemispherical shape at the tip side, and is in direct contact (contact) with the outer peripheral surface of the intermediate cylinder 17, and is electrically connected to the intermediate cylinder 17. The base end side of the electrode pin 22C is a connector portion 22D, and the connector portion 22D is connected to the positive electrode side of the battery 21 via the high voltage driver.

  Thus, in the electric field applying body 22, the sealing cylinder 22 </ b> A is fixed to the mounting hole 3 </ b> B of the outer cylinder 3 from the outside, and the distal end side of the electrode pin 22 </ b> C is in contact with the outer peripheral surface of the intermediate cylinder 17. In other words, the electric field applying body 22 applies an electric field to the electrorheological fluid (working fluid 20) in the passage 18 between the inner cylinder 2 and the intermediate cylinder 3, so that the outer periphery of the intermediate cylinder 17 from the outside of the outer cylinder 3. Projecting toward the surface, the intermediate cylinder 17 is set at a higher potential than the inner cylinder 2.

  Here, between the outer cylinder 3 and the intermediate cylinder 17, spark suppression members 23 and 24 that suppress the occurrence of sparks from the electrode pins 22 </ b> C of the electric field applying body 22 into the reservoir chamber A are provided. . The spark suppressing members 23 and 24 are provided at positions spaced apart in the axial direction of the reservoir chamber A with the electric field applying body 22 interposed therebetween. In the reservoir chamber A, the spark suppressing member 23 is disposed at a position between the rod guide 9 (holding member 10) and the electric field applying body 22, and the spark suppressing member 24 is connected to the bottom cap 4 (holding member 14). It is arranged at a position between the electric field applying body 22.

  In the reservoir chamber A between the outer cylinder 3 and the intermediate cylinder 17, the spark suppressing members 23 and 24 are disposed at positions close to the electric field applying body 22 at positions where the electric field applying body 22 is sandwiched from both axial sides. Yes. The spark suppression member 23 suppresses, for example, the occurrence of a spark from the electrode pin 22C in the direction indicated by the arrow A1 toward the reservoir chamber A. Similarly, the spark suppression member 24 suppresses the occurrence of a spark from the electrode pin 22C in the direction indicated by the arrow A2 toward the reservoir chamber A.

  The spark suppressing members 23 and 24 are constituted by mesh-like net members that allow the working fluid 20 to flow in the reservoir chamber A and block the passage of the spark. As shown in FIG. 3 and FIG. 4, the spark suppressing member 23 is formed as an annular body having a radially inner inner peripheral portion 23 </ b> A and a radially outer peripheral portion 23 </ b> B by a metal mesh. It extends over the entire circumference between the intermediate cylinder 17. The mesh diameter of the spark suppressing member 23 is formed, for example, having a mesh between 50 and 500 μm, preferably between 70 and 200 μm.

  The inner peripheral portion 23 </ b> A of the spark suppressing member 23 has a diameter corresponding to the outer diameter of the intermediate cylinder 17. On the other hand, the outer peripheral portion 23B of the spark suppressing member 23 has an outer diameter larger than the inner diameter of the outer cylinder 3, and is formed to be able to expand and contract in the radial direction. Thereby, when attaching the spark suppression member 23 between the outer cylinder 3 and the intermediate cylinder 17, it is elastically deformed so that the outer peripheral part 23B side of the spark suppression member 23 is reduced in diameter, and is inserted into the inner peripheral side of the outer cylinder 3. In this state, the spark suppression member 23 is positioned between the outer cylinder 3 and the intermediate cylinder 17 as shown in FIG.

  The spark suppression member 24 is also formed as an annular body made of a mesh like the spark suppression member 23 described above, and has a radially inner inner peripheral portion 24A and a radially outer peripheral portion 24B. The outer peripheral portion 24 </ b> B of the spark suppressing member 24 is formed such that its outer diameter corresponds to the inner diameter of the outer cylinder 3. On the other hand, the inner peripheral portion 24A of the spark suppressing member 24 has an inner diameter smaller than the outer diameter of the intermediate cylinder 17, and is formed so as to be able to expand and contract. As a result, when the spark suppression member 24 is attached between the outer cylinder 3 and the intermediate cylinder 17, the spark suppression member 24 is elastically deformed so that the inner peripheral portion 24 </ b> A side of the spark suppression member 24 is expanded and inserted into the outer peripheral side of the intermediate cylinder 17. In this state, the spark suppression member 24 is positioned between the outer cylinder 3 and the intermediate cylinder 17 as shown in FIG.

  Here, the spark suppressing members 23, 24 are provided with the inner peripheral portions 23A, 24A of electrically insulating seal members 25, 26 over the entire circumference. Among these, the seal member 25 is elastically deformed when the inner peripheral portion 23 </ b> A of the spark suppressing member 23 is attached to the outer peripheral surface of the intermediate cylinder 17, and is attached to the outer peripheral surface of the intermediate cylinder 17 with a tightening margin. At this time, the seal member 25 electrically insulates, for example, the metal spark suppression member 23 from the outer peripheral surface of the intermediate cylinder 17. The seal member 26 is elastically deformed when the inner peripheral portion 24A of the spark suppressing member 24 is attached to the outer peripheral surface of the intermediate cylinder 17, and is attached to the outer peripheral surface of the intermediate cylinder 17 with a tightening margin. At this time, the seal member 26 electrically insulates, for example, the metal spark suppressing member 24 from the outer peripheral surface of the intermediate cylinder 17.

  The spark suppression members 23 and 24 are provided with electrical insulation with respect to the intermediate cylinder 17 by the seal members 25 and 26. The spark suppression members 23 and 24 are formed of a material having flame retardancy and a function of reducing the spark temperature (flame temperature).

  The shock absorber 1 according to the first embodiment has the above-described configuration, and the operation thereof will be described next.

  When mounting the shock absorber 1 on a vehicle such as an automobile, for example, the upper end side of the piston rod 8 is attached to the vehicle body side, and the lower end side (bottom cap 4 side) of the outer cylinder 3 is on the wheel side (axle side). Install. When the vehicle is traveling, if upward and downward vibrations are generated due to unevenness of the road surface, the piston rod 8 is displaced so as to extend and contract from the outer cylinder 3. At this time, a potential difference based on a damping force command from the controller is generated between the inner cylinder 2 and the intermediate cylinder 17 to apply an electric field in the passage 18 and the working fluid 20 (that is, the electric fluid 20 passing through the passage 18). By controlling the viscosity of the viscous fluid), the generated damping force of the shock absorber 1 is variably adjusted.

  For example, during the extension stroke of the piston rod 8, the contraction-side check valve 6 of the piston 5 is closed by the movement of the piston 5 in the inner cylinder 2. Before the disc valve 7 of the piston 5 is opened, the working fluid 20 in the rod side oil chamber B is pressurized and flows into the passage 18 through the oil hole 2 </ b> A of the inner cylinder 2. At this time, the liquid corresponding to the movement of the piston 5 flows from the reservoir chamber A into the bottom oil chamber C by opening the extension check valve 15 of the bottom valve 12.

  On the other hand, in the contraction stroke of the piston rod 8, the contraction-side check valve 6 of the piston 5 is opened by the movement of the piston 5 in the inner cylinder 2, and the expansion-side check valve 15 of the bottom valve 12 is closed. The liquid in the bottom side oil chamber C flows into the rod side oil chamber B before the bottom valve 12 (disc valve 16) is opened. At the same time, the liquid corresponding to the amount that the piston rod 8 has entered the inner cylinder 2 flows from the rod-side oil chamber B into the passage 18 through the oil hole 2A of the inner cylinder 2.

  In either case (both the expansion stroke and the contraction stroke), the working fluid 20 that has flowed into the passage 18 has a viscosity corresponding to the electric field strength of the passage 18 (potential difference between the inner cylinder 2 and the intermediate cylinder 17). The inside flows toward the outlet side (lower side) and flows from the passage 18 to the reservoir chamber A through the oil passage 14A of the holding member 14. At this time, the shock absorber 1 generates a damping force corresponding to the viscosity of the working fluid 20 passing through the passage 18 and can buffer (attenuate) the vertical vibration of the vehicle.

  Here, a high voltage is supplied to the intermediate cylinder 17 that forms the reservoir chamber A with the outer cylinder 3 from the outside of the shock absorber 1 (battery 21) via the high voltage driver via the electric field applying body 22. (Applied). At this time, the working fluid 20 that circulates in the reservoir chamber A along with the expansion and contraction of the piston rod 8 circulates around the electrode pins 22 </ b> C so as to contact the electrode pins 22 </ b> C of the electric field applying body 22. However, in such a state, in the reservoir chamber A of the shock absorber 1, a spark due to a discharge phenomenon occurs from the electrode pin 22C of the electric field applying body 22 toward the working fluid 20 (electrorheological fluid) in the reservoir chamber A. This may cause deterioration of the electrorheological fluid.

  Therefore, in the first embodiment, the spark suppression member 23 that suppresses the occurrence of sparks from the electrode pins 22C of the electric field applying body 22 into the reservoir chamber A between the outer cylinder 3 and the intermediate cylinder 17. 24 is provided. The spark suppression members 23 and 24 are provided at positions spaced apart in the axial direction of the reservoir chamber A with the electric field applying body 22 interposed therebetween. For example, the spark from the electrode pin 22C faces the reservoir chamber A in FIG. Suppresses occurrence in the direction of arrows A1 and A2.

  The spark suppression members 23 and 24 are made of a material such as a metal mesh, permitting the working fluid 20 to flow in the direction of the arrows A1 and A2 in the reservoir chamber A, and blocking the passage of the spark. It is the composition to do. Thereby, it can suppress that a spark generate | occur | produces in the reservoir chamber A from the electrode pin 22C of the electric field provision body 22, suppresses that electrorheological fluid deteriorates, and durability and lifetime of the buffer 1 are suppressed. Can be improved.

  Therefore, according to the first embodiment, by providing the spark suppressing members 23 and 24 between the outer cylinder 3 and the intermediate cylinder 17, the electrode pin 22 </ b> C of the electric field applying body 22 is directed into the reservoir chamber A. It is possible to suppress the occurrence of sparks and to suppress the deterioration of the working fluid 20 made of an electrorheological fluid. Moreover, the spark temperature (flame temperature) can be reduced by the spark suppression members 23 and 24, and flame retardance can be ensured. Thereby, the durability as the shock absorber 1 can be improved and the life can be improved. Here, reducing the spark temperature means not reducing the flame resistance of the electrorheological fluid and gas as the working fluid 20 in the spark suppression members 23 and 24 and the reservoir chamber A, but lowering the flame temperature. This means that the flame is prevented from propagating in the reservoir chamber A. Therefore, the flame retardance of the spark suppressing members 23 and 24 is ensured by selecting the material. Furthermore, flame retardance can be ensured also by selecting the material of the working fluid in the reservoir chamber A.

  Next, FIG. 5 shows a second embodiment. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. However, the feature of the second embodiment resides in that an electrically insulating film 31 (coating) is partially provided on the outer peripheral surface of the intermediate cylinder 17 constituting the cylindrical electrode.

  Here, the electrically insulating film 31 is provided in place of the sealing members 25 and 26 described in the first embodiment. The coating 31 is formed so as to cover the entire periphery of the outer peripheral surface of the intermediate cylinder 17 where the inner peripheral portions 23A and 24A of the spark suppressing members 23 and 24 are in contact. Thereby, the film 31 electrically insulates, for example, the metal spark suppressing members 23 and 24 from the outer peripheral surface of the intermediate cylinder 17.

  For example, one cutout portion 31 </ b> A is formed in the film 31. The electrode pins 22C of the electric field applying body 22 are arranged such that their tip portions are in contact (contact) with the outer peripheral surface of the intermediate cylinder 17 through the notches 31A and are electrically connected. The formation position of the coating 31 is not necessarily one, and for example, the coating 31 may be provided by being divided into a plurality of portions for contact with the inner peripheral portions 23A, 24A of the spark suppressing members 23, 24.

  Thus, also in the second embodiment configured as described above, by providing the spark suppressing members 23, 24 between the outer cylinder 3 and the intermediate cylinder 17, the reservoir chamber A can be removed from the electrode pin 22C of the electric field applying body 22. It is possible to suppress the occurrence of sparks toward the inside, and the same effect as in the first embodiment can be obtained. In particular, according to the second embodiment, it is only necessary to coat the outer peripheral surface of the intermediate cylinder 17 with the electrically insulating film 31, and the workability can be improved.

  In the first embodiment, the spark suppression member 23 is disposed at a position between the rod guide 9 (holding member 10) and the electric field applying body 22, and the spark suppression member 24 is connected to the bottom cap 4 (holding). The case where it arrange | positions in the position between the member 14) and the electric field provision body 22 was mentioned as an example, and was demonstrated. However, the present invention is not limited to this. For example, the spark suppression member 24 is disposed between the outer cylinder 3 and the intermediate cylinder 17 at a position between the rod guide 9 (holding member 10) and the electric field applying body 22. The spark suppression member 23 may be arranged at a position between the bottom cap 4 (holding member 14) and the electric field applying body 22.

  In the first embodiment, the case where the spark suppressing members 23 and 24 are provided between the outer cylinder 3 and the intermediate cylinder 17 has been described as an example. However, the present invention is not limited to this. For example, the spark suppression member 23 may be provided between the outer cylinder 3 and the intermediate cylinder 17 and the spark suppression member 24 may be omitted. Further, the spark suppression member 24 may be provided between the outer cylinder 3 and the intermediate cylinder 17 and the spark suppression member 23 may be omitted. This is the same for the second embodiment.

  Moreover, in the said 1st Embodiment, the case where the spark suppression members 23 and 24 were formed using metal mesh was mentioned as an example, and was demonstrated. However, the present invention is not limited to this, and the spark suppression member may be constituted by a mesh made of an insulating material such as a synthetic resin. In this case, there is no need to provide a seal member made of an electrically insulating material on the inner peripheral side of the spark suppressing member. The spark suppressing member is preferably formed of a material having flame retardancy, for example, and a material having a function of reducing the spark temperature (flame temperature).

  Furthermore, in the said embodiment, the case where the shock absorber 1 as a cylinder apparatus was used for a four-wheel vehicle was mentioned as an example, and was demonstrated. However, the present invention is not limited to this. For example, a shock absorber used for a two-wheeled vehicle, a shock absorber used for a railway vehicle, a shock absorber used for various mechanical devices including general industrial equipment, a shock absorber used for a building, etc. It can be widely used as various shock absorbers (cylinder devices) for buffering an object to be processed.

  As the cylinder device based on the embodiment described above, for example, the following modes can be considered.

  As a first aspect of the cylinder device, an electrorheological fluid whose fluid viscosity is changed by an electric field is enclosed, an inner cylinder into which a rod is inserted, an outer cylinder provided outside the inner cylinder, An intermediate cylinder that is provided between the cylinder and the outer cylinder and that forms a passage through which the electrorheological fluid flows between the inner cylinder and the intermediate cylinder and the outer cylinder; A reservoir chamber in which a viscous fluid and a working gas are sealed; a rod guide that is provided to close one end of the inner cylinder and the outer cylinder, and supports the rod so as to be extendable; and the inner cylinder and the intermediate cylinder; In order to apply an electric field to the electrorheological fluid in the passage between, an electric field is applied that protrudes from the outside of the outer cylinder toward the outer peripheral surface of the intermediate cylinder and sets the intermediate cylinder to a higher potential than the inner cylinder. Between the outer cylinder and the intermediate cylinder, Spark suppression member suppressing the electric field imparting body of the spark is generated toward the reservoir chamber is provided.

  The cylinder device according to a second aspect is the cylinder device according to the first aspect, wherein the spark suppression member is a mesh-like net member that allows the electrorheological fluid to flow in the reservoir chamber and blocks passage of the spark. It is configured. As a third aspect, in the first or second aspect, the spark suppressing member is formed of a metal mesh. As a fourth aspect, in any one of the first to third aspects, the spark suppressing member has a mesh having a mesh diameter of 50 to 500 μm, preferably 70 to 200 μm.

  In the cylinder device according to a fifth aspect, in any one of the first to fourth aspects, the spark suppressing member is electrically insulated from the outer peripheral surface of the intermediate cylinder. The cylinder device according to a sixth aspect is the cylinder device according to any one of the first to fifth aspects, wherein an inner diameter of the spark suppressing member corresponds to an outer diameter of the intermediate cylinder, and an outer diameter of the spark suppressing member is the outer cylinder. The inner diameter is larger than the inner diameter, and the diameter can be increased or decreased.

  The cylinder device according to a seventh aspect is the cylinder device according to any one of the first to fifth aspects, wherein the spark suppressing member has an outer diameter corresponding to an inner diameter of the outer cylinder, and the inner diameter of the spark suppressing member is that of the intermediate cylinder. It is smaller than the outer diameter and is formed to be able to expand and contract. The cylinder device according to an eighth aspect is the cylinder device according to any one of the first to seventh aspects, wherein the spark suppression member is provided at a position spaced apart in the axial direction of the reservoir chamber with the electric field applying body interposed therebetween. Yes.

1 Shock absorber (cylinder device)
2 Inner cylinder 3 Outer cylinder 5 Piston 8 Piston rod (rod)
9 Rod guide 17 Intermediate cylinder 18 Passage 20 Working fluid (electroviscous fluid)
DESCRIPTION OF SYMBOLS 21 Battery 22 Electric field imparting body 23, 24 Spark suppression member 25, 26 Seal member 31 Coating A Reservoir chamber B Rod side oil chamber C Bottom side oil chamber

Claims (8)

An inner cylinder in which an electrorheological fluid in which the viscosity of the fluid is changed by an electric field is enclosed, and a rod is inserted therein;
An outer cylinder provided outside the inner cylinder;
An intermediate cylinder which is provided between the inner cylinder and the outer cylinder and forms a passage through which the electrorheological fluid flows;
A reservoir chamber formed between the intermediate cylinder and the outer cylinder and enclosing the electrorheological fluid and working gas;
A rod guide that is provided so as to close one end of the inner cylinder and the outer cylinder, and supports the rod in an extendable manner;
In order to apply an electric field to the electrorheological fluid in the passage between the inner cylinder and the intermediate cylinder, the outer cylinder protrudes from the outside of the outer cylinder toward the outer peripheral surface of the intermediate cylinder, and the intermediate cylinder is protruded from the inner cylinder. And an electric field applying body that is set to a high potential,
A cylinder device characterized in that a spark suppressing member is provided between the outer cylinder and the intermediate cylinder to suppress the occurrence of spark from the electric field applying body toward the reservoir chamber.   2. The cylinder according to claim 1, wherein the spark suppressing member is configured by a mesh-like net member that allows the electrorheological fluid to flow in the reservoir chamber and blocks passage of the spark. apparatus.   The cylinder device according to claim 1, wherein the spark suppressing member is formed of a metal mesh.   The cylinder device according to any one of claims 1 to 3, wherein the spark suppressing member has a mesh having a mesh diameter of 50 to 500 µm, preferably 70 to 200 µm.   The cylinder device according to any one of claims 1 to 4, wherein the spark suppressing member is electrically insulated from an outer peripheral surface of the intermediate cylinder.   The spark suppressing member has an inner diameter corresponding to an outer diameter of the intermediate cylinder, and the spark suppressing member has an outer diameter larger than an inner diameter of the outer cylinder, and is formed to be able to expand and contract. The cylinder apparatus in any one of thru | or 5.   The outer diameter of the spark suppressing member corresponds to the inner diameter of the outer cylinder, and the inner diameter of the spark suppressing member is smaller than the outer diameter of the intermediate cylinder and is formed to be able to expand and contract. The cylinder apparatus in any one of thru | or 5.   The cylinder device according to any one of claims 1 to 7, wherein the spark suppressing member is provided at a position spaced apart in the axial direction of the reservoir chamber with the electric field applying body interposed therebetween.

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