JP2019007600A - Cylinder device - Google Patents

Abstract

To prevent occurrence of abnormal noise by inhibiting stick-slip of an electroviscous fluid.SOLUTION: An outer peripheral side of an inner cylindrical electrode 3 and an inner peripheral side of an outer cylindrical electrode 19, specifically an outer peripheral surface of the inner cylindrical electrode 3, have an inner cylinder side insulator layer 23 to interrupt an electrical current to an electroviscous fluid 2 flowing in each inter-electrode flow channel 20. An inner peripheral surface 19A of the outer cylindrical electrode 19 has an outer cylinder side insulator layer 24 to interrupt the electrical current to the electroviscous fluid 2 flowing in each inter-electrode flow channel 20.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a cylinder device suitably used for buffering vibration of a vehicle such as an automobile or a railway vehicle.

  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. Here, in Patent Document 1, in a damper (buffer) using an electrorheological fluid as a working fluid, a spiral sealing means is provided in a flow path between an inner cylinder and an electrode cylinder (intermediate cylinder). A configuration is disclosed.

International Publication No. 2014/135183

  By the way, in the cylinder device disclosed in Patent Document 1, when the electrorheological fluid flows through the flow path between the inner cylinder and the electrode cylinder, stick slip may occur in the electrorheological fluid. Wear may occur.

  An object of the present invention is to provide a cylinder device capable of preventing the generation of abnormal noise by suppressing stick-slip of an electrorheological fluid.

  According to the present invention, a cylinder device in which an electrorheological fluid whose viscosity is changed by an electric field is sealed and a rod is inserted therein, the inner cylinder electrode serving as electrodes having different potentials, and the inner cylinder electrode An outer cylinder electrode provided on the outer side, the inner cylinder electrode and the outer cylinder electrode are formed between the inner cylinder electrode and the outer cylinder electrode, and the electrorheological fluid flows from one side in the axial direction toward the other side by movement of at least the extension side of the rod. A flow path that flows, and a sealing means provided in the flow path with an inclination angle with respect to the axial direction, out of the outer peripheral side of the inner cylindrical electrode and the inner peripheral side of the outer cylindrical electrode An insulating layer that cuts off current to the electrorheological fluid flowing in the flow path is provided at least on the inner peripheral side of the outer cylinder electrode.

  According to the present invention, abnormal noise can be prevented by suppressing stick-slip of an electrorheological fluid.

It is a longitudinal cross-sectional view which shows the shock absorber as a cylinder apparatus by 1st Embodiment. It is a longitudinal cross-sectional view which shows an inner cylinder electrode, an outer cylinder electrode, a partition (sealing means), an inner cylinder side insulating layer, and an outer cylinder side insulating layer. FIG. 3 is a cross-sectional view of an inner cylinder electrode, an outer cylinder electrode, a partition wall (sealing means), an inner cylinder side insulating layer, and an outer cylinder side insulating layer as viewed from the direction of arrows III-III in FIG. 2. It is the cross-sectional view which looked at the inner cylinder electrode by the 2nd embodiment, the outer cylinder electrode, the partition (sealing means), and the insulating layer from the same position as FIG.

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

  1 to 3 show a first embodiment of the present invention. In FIG. 1, a shock absorber 1 as a cylinder device is configured as a damping force adjustment type hydraulic shock absorber (semi-active damper) using an electrorheological fluid 2 such as hydraulic oil sealed inside. 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 the “upper end” side, and the other end side in the axial direction is referred to as the “lower end” side. The other end side in the axial direction may be the “upper end” side.

  The shock absorber 1 includes an inner cylinder electrode 3, an outer cylinder 4, a piston 6, a piston rod 9, a bottom valve 13, an outer cylinder electrode 19, an inner cylinder side insulating layer 23 and an outer cylinder side insulating layer 24 which will be described later. ing.

  The inner cylinder electrode 3 is formed as a cylindrical cylinder extending in the axial direction, and an electrorheological fluid 2 that is a functional fluid is sealed therein. A piston rod 9 is inserted into the inner cylinder electrode 3. The outer cylinder 4 and the outer cylinder electrode 19 are provided on the outer side of the inner cylinder electrode 3 so as to be coaxial. A piston rod 9 is inserted into the inner cylinder electrode 3 so as to be expandable and contractable in the axial direction.

  The lower end side of the inner cylinder electrode 3 is fitted and attached to the valve body 14 of the bottom valve 13, and the upper end side is fitted and attached to the rod guide 10. A plurality of (for example, four) oil holes 3 </ b> A are provided on the upper side of the inner cylinder electrode 3 in the radial direction with intervals in the circumferential direction. In addition, a plurality of (for example, four) partition walls 21 are spirally wound around the outer peripheral surface 3B that forms the outer peripheral side of the inner cylindrical electrode 3 together with an inner cylinder-side insulating layer 23 described later. .

  Here, the inner cylinder electrode 3 is formed of a material that becomes a conductor (electric conductor), and is configured as a negative (minus) electrode. The inner cylinder electrode 3 is electrically connected to the negative electrode (minus electrode) of the battery 22 via an outer cylinder 4, a rod guide 10, a bottom valve 13, and the like, which will be described later.

  The outer cylinder 4 forms an outer shell of the shock absorber 1 and is formed as a cylindrical body by a material serving as a conductor. The outer cylinder 4 is provided outside the inner cylinder electrode 3 and the outer cylinder electrode 19, and forms a reservoir chamber A communicating with the inter-electrode flow path 20 between the outer cylinder electrode 19. In this case, the lower end side of the outer cylinder 4 is a closed end by fixing the bottom cap 5 to the lower end of the outer cylinder 4 using welding means or the like.

  On the other hand, the upper end side of the outer cylinder 4 is an open end. On the opening end side of the outer cylinder 4, for example, a caulking portion 4 </ b> A is formed to be bent inward in the radial direction. The caulking portion 4 </ b> A fixes the inner cylinder electrode 3, the rod guide 10, and the outer cylinder electrode 19 together with the seal member 12 in the outer cylinder 4 by pressing the outer peripheral side of the seal member 12 from the upper side.

  Here, the inner cylinder electrode 3 and the outer cylinder 4 constitute a cylinder, and an electrorheological fluid 2 (ERF: Electro Rheological Fluid) is sealed in the cylinder. In FIG. 1, the encapsulated electrorheological fluid 2 is shown as colorless and transparent.

  The electrorheological fluid 2 changes its properties depending on the electric field (voltage). That is, the viscosity of the electrorheological fluid 2 changes according to the applied voltage, and the flow resistance (damping force) changes. The electrorheological fluid 2 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 changes in the electric field. ing.

  As will be described later, the shock absorber 1 generates a potential difference in the interelectrode flow path 20 between the inner cylindrical electrode 3 and the outer cylindrical electrode 19, and the viscosity of the electrorheological fluid 2 passing through the interelectrode flow path 20 is reduced. By controlling, the generated damping force is controlled (adjusted).

  An annular reservoir chamber A is formed between the outer cylinder 4 and the outer cylinder electrode 19. In the reservoir chamber A, a gas serving as a working gas is sealed together with the electrorheological fluid 2. This gas may be atmospheric pressure air or a compressed gas such as nitrogen gas. The gas in the reservoir chamber A is compressed during the contraction stroke of the piston rod 9 to compensate for the entry volume of the piston rod 9.

  The piston 6 is slidably provided in the inner cylinder electrode 3. The piston 6 partitions the inside of the inner cylinder electrode 3 into a rod side oil chamber B located on the upper side and a bottom side oil chamber C located on the lower side. The piston 6 is formed with a plurality of oil passages 6A and 6B (only one is shown) that are spaced apart from each other in the circumferential direction so that the rod-side oil chamber B and the bottom-side oil chamber C can communicate with each other.

  Here, the shock absorber 1 according to the embodiment has a uniflow structure. For this reason, the electrorheological fluid 2 in the inner cylinder electrode 3 flows from the rod-side oil chamber B through the oil holes 3A of the inner cylinder electrode 3 through the oil holes 3A in both the reduction stroke and the extension stroke of the piston rod 9. It always circulates in one direction (the direction of arrow F in FIG. 1) toward 20.

  In order to realize such a uniflow structure, for example, the piston 6 is opened on the upper end surface of the piston 6 when the piston 6 is slid downwardly in the inner cylinder electrode 3 during the reduction stroke of the piston rod 9. In this case, a reduction-side check valve 7 that is closed is provided. The reduction-side check valve 7 allows the electrorheological fluid 2 in the bottom side oil chamber C to flow in each oil passage 6A toward the rod side oil chamber B, and in the opposite direction, the electrorheological fluid 2 Is prevented from flowing. That is, the reduction-side check valve 7 allows only the flow of the electrorheological fluid 2 from the bottom side oil chamber C to the rod side oil chamber B.

  On the lower end surface of the piston 6, for example, an extension-side disc valve 8 is provided. The extension-side disc valve 8 opens when the pressure in the rod-side oil chamber B exceeds the relief set pressure when the piston 6 slides upward in the inner cylinder electrode 3 in the extension stroke of the piston rod 9. Then, the pressure at this time is relieved to the bottom side oil chamber C side through each oil passage 6B.

  The piston rod 9 as a rod extends in the inner cylinder electrode 3 in the axial direction (vertical direction in FIG. 1). The lower end of the piston rod 9 is connected (fixed) to the piston 6 using a nut 9 </ b> A or the like in the inner cylinder electrode 3, and the upper end extends outside the inner cylinder electrode 3 and the outer cylinder 4 through the rod side oil chamber B. Has been issued. Further, the upper end side of the piston rod 9 protrudes to the outside through the rod guide 10. The shock absorber may be a double rod type in which the lower end of the piston rod 9 is further extended to protrude outward from the bottom portion (for example, the bottom cap 5) side.

  The rod guide 10 is provided to be fitted to the upper ends of the inner cylinder electrode 3 and the outer cylinder 4. The rod guide 10 closes the upper ends of the inner cylinder electrode 3 and the outer cylinder 4. The rod guide 10 supports the piston rod 9 via a guide bush 11 and is formed as a stepped cylinder by, for example, forming or cutting a metal material, a hard resin material, or the like. . In this case, the rod guide 10 can be formed using a material made of an insulator, a dielectric, a high resistance, or the like, for example, a resin material, when a valve body 14 described later is a metal material (conductor). The rod guide 10 positions the upper part of the inner cylinder electrode 3 and the upper part of the outer cylinder electrode 19 at the center of the outer cylinder 4. At the same time, the rod guide 10 guides (guides) the piston rod 9 so as to be slidable in the axial direction on the inner peripheral side.

  An annular seal member 12 is provided between the rod guide 10 and the caulking portion 4A of the outer cylinder 4. The seal member 12 has a liquid-tight and air-tight seal (seal) between the seal member 12 and the piston rod 9 by the inner peripheral side thereof being in sliding contact with the outer peripheral surface of the piston rod 9.

  On the lower end side of the inner cylinder electrode 3, a bottom valve 13 is provided between the inner cylinder electrode 3 and the bottom cap 5. The bottom valve 13 communicates or blocks the bottom side oil chamber C and the reservoir chamber A. For this purpose, the bottom valve 13 includes a valve body 14, an extension-side check valve 15 and a disc valve 16. The valve body 14 partitions the reservoir chamber A and the bottom oil chamber C between the bottom cap 5 and the inner cylinder electrode 3.

  In the valve body 14, oil passages 14 </ b> A and 14 </ b> B that allow the reservoir chamber A and the bottom side oil chamber C to communicate with each other are formed at intervals in the circumferential direction. The lower end of the inner cylinder electrode 3 is fitted and fixed to the outer peripheral side of the valve body 14. Further, a lower holding member 18 described later is fitted and attached to the outer peripheral side of the valve body 14 so as to be positioned on the outer peripheral side of the inner cylinder electrode 3. Here, when the rod guide 10 described above is a metal material (conductor), the valve body 14 may be formed using a material made of an insulator, a dielectric, a high resistance, or the like, for example, a hard resin material. it can.

  The extension side check valve 15 is provided on the upper surface side of the valve body 14, for example. The extension-side check valve 15 opens when the piston 6 slides upward in the extension stroke of the piston rod 9, and closes at other times. The extension side check valve 15 allows the electrorheological fluid 2 in the reservoir chamber A to flow through each oil passage 14A toward the bottom side oil chamber C, and the electrorheological fluid 2 flows in the opposite direction. To prevent it. That is, the extension side check valve 15 allows only the flow of the electrorheological fluid 2 from the reservoir chamber A side to the bottom side oil chamber C side.

  The reduction-side disc valve 16 is provided on the lower surface side of the valve body 14, for example. 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 6 slides downward in the reduction stroke of the piston rod 9, and the pressure at this time Is relieved to the reservoir chamber A side through each oil passage 14B.

  The upper holding member 17 is fitted to the outer peripheral side of the rod guide 10 so as to surround the upper part of the inner cylindrical electrode 3. The upper holding member 17 holds the upper end side of the outer cylinder electrode 19 in a state of being positioned in the axial direction and the radial direction. The upper holding member 17 is made of, for example, an electrically insulating material (isolator), and keeps the inner cylinder electrode 3 and the rod guide 10 and the outer cylinder electrode 19 electrically insulated.

  On the other hand, the lower holding member 18 holds the lower end side of the outer cylinder electrode 19 in a state of being positioned in the axial direction and the radial direction. Similarly to the upper holding member 17, the lower holding member 18 is formed of, for example, an electrically insulating material (isolator), and between the inner cylinder electrode 3 and the outer cylinder electrode 19, between the valve body 14 and the outer cylinder electrode 19. They are kept in an electrically insulated state. The lower holding member 18 is formed with a plurality of oil passages 18 </ b> A that allow the interelectrode flow path 20 to communicate with the reservoir chamber A.

  The outer cylinder electrode 19 is provided outside the inner cylinder electrode 3 so as to surround the inner cylinder electrode 3. The outer cylinder electrode 19 is formed by a cylindrical body that is positioned between the inner cylinder electrode 3 and the outer cylinder 4 and extends in the axial direction. The outer cylinder electrode 19 is made of a material that becomes a conductor (for example, a metal material), and constitutes a positive electrode. Between the outer cylinder electrode 19 and the inner cylinder electrode 3, an interelectrode flow path 20 that communicates with the rod-side oil chamber B and the reservoir chamber A is formed. The outer cylinder electrode 19 is electrically connected to a positive electrode (plus electrode) of a battery 22 described later.

  The outer cylinder electrode 19 is held in a state in which the lower end side is positioned in the vertical and radial directions with respect to the valve body 14 of the bottom valve 13 via the lower holding member 18. On the other hand, the upper end side of the outer cylinder electrode 19 is held in a state of positioning in the vertical direction and the radial direction with respect to the rod guide 10 via the upper holding member 17. In addition, an outer cylinder side insulating layer 24 described later is provided on the inner peripheral surface 19 </ b> A that forms the inner peripheral side of the outer cylinder electrode 19.

  Here, the outer cylinder electrode 19 surrounds the outer circumference side of the inner cylinder electrode 3 over the entire circumference, so that an annular passage is formed between the inner circumference side of the outer cylinder electrode 19 and the outer circumference side of the inner cylinder electrode 3. That is, the interelectrode flow path 20 is formed as a flow path through which the electrorheological fluid 2 flows.

  The inter-electrode flow path 20 is divided into a plurality of, for example, four by each partition wall 21 described later. Each inter-electrode channel 20 is always in communication with the rod-side oil chamber B through the oil hole 3 </ b> A of the inner cylinder electrode 3. That is, as shown by the arrow F in the direction of the flow of the electrorheological fluid 2 in FIG. 1, the shock absorber 1 is disposed between the electrodes from the rod side oil chamber B through the oil holes 3A in both the contraction stroke and the expansion stroke of the piston 6. The electrorheological fluid 2 flows into the flow path 20. The electrorheological fluid 2 that has flowed into the interelectrode flow path 20 flows between the electrodes when the piston rod 9 moves back and forth in the inner cylinder electrode 3 (that is, while the reduction stroke and the extension stroke are repeated). It flows from the upper end side in the axial direction of the path 20 toward the lower end side. Then, the electrorheological fluid 2 that has flowed into the interelectrode flow path 20 flows out into the reservoir chamber A via the oil path 18A of the lower holding member 18.

  The plurality of partition walls 21 as sealing means are provided to extend in the vertical direction while spirally winding so as to surround the outer peripheral surface 3B of the inner cylindrical electrode 3. For example, four partition walls 21 are formed, and the interelectrode channel 20 is partitioned into a plurality (four) of spiral channels. Each partition wall 21 is made of a polymer material having elasticity such as elastomer and having electrical insulation properties, for example, synthetic rubber. Each partition wall 21 is fixed (adhered) to the outer peripheral surface 3B of the inner cylinder 3, for example, an inner cylinder side insulating layer 23 described later coated on the outer peripheral surface 3B of the inner cylinder 3 using an adhesive or the like. ing.

  As shown in FIG. 2, oil holes 3 </ b> A of the inner cylinder electrode 3 are provided at a position above each partition wall 21 and at a position facing (facing) the upper end portion of each partition wall 21 in the axial direction. . That is, the oil hole 3A of the inner cylinder electrode 3 and the upper end portion of each partition wall 21 are arranged so as to coincide with the axial direction. Note that the position of the oil hole 3 </ b> A is not limited to this, and may be provided at a position above each partition wall 21 and between the partition walls 21. In addition, when the shock absorber 1 has a biflow structure, an oil hole is provided in the inner cylinder electrode 3 at a position below each partition wall 21 in addition to the oil hole 3A.

  Here, in each inter-electrode flow path 20 divided by each partition wall 21, resistance is applied to the electrorheological fluid 2 circulated when the piston 6 slides in the inner cylinder electrode 3. For this purpose, the outer cylinder electrode 19 is connected to the positive electrode of the battery 22 serving as a power source via, for example, a high voltage driver (not shown) that generates a high voltage. The battery 22 (and the high voltage driver) serves as a voltage supply unit (electric field supply unit), and the outer cylinder electrode 19 includes an electrode (electrode) that applies an electric field (voltage) to the electrorheological fluid 2 in the interelectrode flow path 20. Become. In this case, both end sides of the outer cylinder electrode 19 are electrically insulated by the electrically insulating holding members 17 and 18. On the other hand, the inner cylinder electrode 3 is connected to the negative electrode (ground) via the rod guide 10, the bottom valve 13, the bottom cap 5, the outer cylinder 4, a high voltage driver, and the like.

  The high voltage driver boosts the DC voltage output from the battery 22 based on a command (high voltage command) output from a controller (not shown) for variably adjusting the damping force of the shock absorber 1. Supply (output) to the outer cylinder electrode 19. As a result, a potential difference corresponding to the voltage applied to the outer cylinder electrode 19 is generated between the outer cylinder electrode 19 and the inner cylinder electrode 3, that is, in each inter-electrode flow path 20. Viscosity changes. In this case, the shock absorber 1 changes the generated damping force characteristics (damping force characteristics) into a soft characteristic (soft characteristic) and a hard characteristic (hard characteristic) according to the voltage applied to the outer cylinder electrode 19. (Hard characteristics) can be continuously adjusted. The shock absorber 1 may be capable of adjusting the damping force characteristics in two stages or three or more stages without being continuous.

  Next, the configuration of the inner cylinder side insulating layer 23 and the outer cylinder side insulating layer 24 which are characteristic portions of the first embodiment will be described.

  As shown in FIG. 3, the inner cylinder side insulating layer 23 as an insulating layer extends over the entire length of each inter-electrode flow path 20 so as to cover the outer peripheral surface 3 </ b> B of the inner cylindrical electrode 3 on the outer peripheral side of the inner cylindrical electrode 3. Is provided. The inner cylinder-side insulating layer 23 blocks the current to the electrorheological fluid 2 that flows through the interelectrode flow paths 20. The inner cylinder-side insulating layer 23 is thinly provided on the outer peripheral surface 3B of the inner cylinder electrode 3 like a nonconductive film. Specifically, the thickness dimension of the inner cylinder side insulating layer 23 is set in the range of 0.1 μm to 20 μm, preferably in the range of 2 μm to 15 μm.

  The inner cylinder side insulating layer 23 is formed on the basis of an insulating resin material such as polyurethane. And the inner cylinder side insulating layer 23 interrupts | blocks the electric current to the electrorheological fluid 2 which flows through each flow path 20 between electrodes, and suppresses the stick slip of the electrorheological fluid 2. As shown in FIG. Further, the four partition walls 21 described above are fixed to the outer peripheral side of the inner cylinder side insulating layer 23.

  The outer cylinder side insulating layer 24 as an insulating layer faces the inner cylinder side insulating layer 23 in the radial direction, and covers the inner peripheral surface 19A of the outer cylindrical electrode 19 on the inner peripheral side of the outer cylindrical electrode 3. It is provided over the entire length of the interelectrode channel 20. The outer cylinder side insulating layer 24 blocks the current to the electrorheological fluid 2 flowing through each inter-electrode flow path 20, similarly to the inner cylinder side insulating layer 23. The outer cylinder-side insulating layer 24 is thinly provided on the inner peripheral surface 19A of the outer cylinder electrode 19 like a nonconductive film. Specifically, the thickness dimension of the outer cylinder side insulating layer 24 is set in the range of 0.1 μm to 20 μm, preferably in the range of 2 μm to 15 μm.

  The outer cylinder side insulating layer 24 is formed on the basis of an insulating resin material such as polyurethane. And the outer cylinder side insulating layer 24 interrupts the electric current to the electrorheological fluid 2 which flows through the flow path 20 between electrodes, and suppresses the stick slip of the electrorheological fluid 2.

  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 9 is attached to the vehicle body side, and the lower end side (bottom cap 5 side) of the outer cylinder 4 is set to the wheel side (axle side). Install. When the vehicle travels, if vertical vibration is generated due to road surface unevenness or the like, the piston rod 9 is displaced from the outer cylinder 4 so as to expand and contract. At this time, the buffer 1 is generated by generating a potential difference in each inter-electrode flow path 20 using the battery 22 in accordance with a command from the controller and controlling the viscosity of the electrorheological fluid 2 passing through each inter-electrode flow path 20. Adjust the generation damping force of the variable.

  During the extension stroke of the piston rod 9, the reduction-side check valve 7 of the piston 6 is closed by the movement of the piston 6 in the inner cylinder electrode 3. Before the disc valve 8 of the piston 6 is opened, the electrorheological fluid 2 in the rod side oil chamber B is pressurized and flows into the interelectrode flow paths 20 through the oil holes 3A of the inner cylinder electrode 3. At this time, the electrorheological fluid 2 corresponding to the movement of the piston 6 flows from the reservoir chamber A into the bottom oil chamber C by opening the extension check valve 15 of the bottom valve 13.

  On the other hand, during the reduction stroke of the piston rod 9, the reduction-side check valve 7 of the piston 6 is opened by the movement of the piston 6 in the inner cylinder electrode 3, and the extension-side check valve 15 of the bottom valve 13 is closed. The electrorheological fluid 2 in the bottom side oil chamber C flows into the rod side oil chamber B before the bottom valve 13 (disc valve 16) is opened. At the same time, the electrorheological fluid 2 corresponding to the amount that the piston rod 9 entered the inner cylinder electrode 3 flows into the interelectrode flow path 20 from the rod side oil chamber B through the oil holes 3A of the inner cylinder electrode 3. To do.

  Therefore, in any case (during the expansion stroke and the reduction stroke), the electrorheological fluid 2 that has flowed into each inter-electrode flow path 20 causes the potential difference between the inter-electrode flow paths 20 (the inner cylinder electrode 3 and the outer cylinder electrode). Pass through each inter-electrode channel 20 toward the outlet side (lower side) with a viscosity corresponding to the potential difference between the electrode 19 and the reservoir through the oil channel 18A of the lower holding member 18 from each inter-electrode channel 20. Flows into chamber A. At this time, the shock absorber 1 generates a damping force corresponding to the viscosity of the electrorheological fluid 2 that passes through each inter-electrode flow path 20 and can buffer (attenuate) the vertical vibration of the vehicle.

  By the way, during operation of the shock absorber 1 described above, stick-slip may occur when the electrorheological fluid 2 flows through each inter-electrode flow path 20, and in this case, abnormal noise is generated by vibration. there is a possibility.

  Therefore, in the present embodiment, the electrorheological fluid 2 that flows through the inter-electrode flow paths 20 on the outer peripheral side of the inner cylindrical electrode 3 and the inner peripheral side of the outer cylindrical electrode 19, specifically, on the outer peripheral surface of the inner cylindrical electrode 3. An inner cylinder side insulating layer 23 is provided to cut off the current to the outer cylinder electrode 19, and an outer cylinder side insulation is provided on the inner peripheral surface 19 A of the outer cylinder electrode 19 to cut off the current to the electrorheological fluid 2 flowing in the interelectrode flow path 20. The layer 24 is provided.

  Thereby, the inner cylinder side insulating layer 23 and the outer cylinder side insulating layer 24 can suppress stick-slip when the electrorheological fluid 2 flows through each inter-electrode channel 20. As a result, it is possible to prevent the generation of abnormal noise during the operation of the shock absorber 1.

  Next, FIG. 4 shows a second embodiment of the present invention. The feature of this embodiment is that an insulating layer is provided only on the inner peripheral side of the outer cylinder electrode. In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 4, the outer cylinder side insulating layer 31 by 2nd Embodiment comprises the insulating layer. Similar to the outer cylinder side insulating layer 24 according to the first embodiment, the outer cylinder side insulating layer 31 is as thin as a non-conductive film on the inner peripheral surface 19A of the outer cylinder electrode 3 constituting the positive (plus) electrode. Is provided. The thickness dimension of the outer cylinder side insulating layer 31 is set in the range of 0.1 μm to 20 μm, preferably in the range of 2 μm to 15 μm. Further, the outer cylinder side insulating layer 31 is formed on the basis of an insulating resin material such as polyurethane. Here, in the second embodiment, the configuration in which the insulating layer is provided only on the positive (plus) electrode is shown. Since it is considered that the polyurethane particles contained in the electrorheological fluid 2 move to the plus side by electrophoresis, it is assumed that the polyurethane particles adhere to the plus electrode, and the plus electrode surface is insulated only on the side where the surface changes. Considering the provision of a layer.

  Thus, also in the second embodiment configured in this way, it is possible to obtain substantially the same operational effects as the operational effects of the first embodiment described above. In particular, according to the second embodiment, since the inner cylinder side insulating layer 23 according to the first embodiment can be omitted, the configuration can be simplified.

  In the second embodiment, the case where the outer cylinder side insulating layer 31 is provided only on the inner peripheral surface 19A of the outer cylinder electrode 3 constituting the positive electrode is described as an example. However, the present invention is not limited to this, and when the inner cylinder electrode 3 is a positive electrode, the inner cylinder side insulating layer may be provided only on the outer peripheral surface 3B of the inner cylinder electrode 3.

  In each embodiment, the case where the shock absorber 1 has a uniflow structure has been described as an example. However, the present invention is not limited to this, and the shock absorber may have a biflow structure. In the case of the biflow structure, the oil hole becomes the outflow part when the forward and backward direction of the rod is reversed.

  In each embodiment, the case where it was set as the structure which arrange | positions the buffer 1 in the up-down direction was mentioned as an example, and was demonstrated. However, the present invention is not limited to this, and can be arranged in a desired direction according to the attachment object, for example, by being inclined and arranged within a range where aeration does not occur.

  In each embodiment, the case where the electrorheological fluid 2 is configured to flow from the upper end side (one end side) in the axial direction toward the lower end side (the other end side) has been described as an example. However, the present invention is not limited to this, and, for example, a structure that flows from the lower end side toward the upper end side according to the arrangement direction of the shock absorber 1, from the left end side (or right end side) to the right end side (or left end side). A structure that flows toward the one end side from the other end side in the axial direction, such as a structure that flows toward the rear end side (or the front end side) from the front end side (or the rear end side). it can.

  In each embodiment, the case where the shock absorber 1 as a cylinder device is used in a four-wheeled vehicle has been described as an example. However, the present invention is not limited to this. For example, a shock absorber used for a motorcycle, 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. The present invention can be widely used as various shock absorbers (cylinder devices) for buffering a target object. Furthermore, the embodiments are exemplifications, and it is needless to say that partial replacements or combinations of the configurations shown in the different embodiments are possible. That is, the design of the cylinder device (buffer) can be changed without departing from the gist of the present invention.

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

  As a first aspect, a cylinder device in which an electrorheological fluid whose viscosity is changed by an electric field is sealed and a rod is inserted therein, an inner cylinder electrode serving as electrodes having different potentials, and the inner cylinder electrode The electrorheological fluid is formed between the outer cylinder electrode provided on the outer side of the cylinder, the inner cylinder electrode and the outer cylinder electrode, and moving from one side of the axial direction to the other side by movement of at least the extension side of the rod. And a sealing means provided in the flow path with an inclination angle with respect to the axial direction, and an outer peripheral side of the inner cylindrical electrode and an inner peripheral side of the outer cylindrical electrode Among them, an insulating layer that cuts off current to the electrorheological fluid flowing in the flow path is provided at least on the inner peripheral side of the outer cylinder electrode.

  As a second aspect, the insulating layer is provided on both the outer peripheral side of the inner cylindrical electrode and the inner peripheral side of the outer cylindrical electrode.

1 Shock absorber (cylinder device)
2 Electrorheological fluid 3 Inner cylinder electrode 3B Outer peripheral surface 4 Outer cylinder 9 Piston rod (rod)
19 outer cylinder electrode 19A inner peripheral surface 20 flow path between electrodes (flow path)
21 Bulkhead (sealing means)
23 Inner cylinder side insulating layer (insulating layer)
24, 31 Outer cylinder side insulating layer (insulating layer)

Claims (2)

A cylinder device in which an electrorheological fluid in which the viscosity of the fluid changes due to an electric field is enclosed, and a rod is inserted therein,
An inner cylinder electrode serving as electrodes having different potentials, and an outer cylinder electrode provided outside the inner cylinder electrode;
A flow path formed between the inner cylinder electrode and the outer cylinder electrode, in which the electrorheological fluid flows from one side to the other side in the axial direction by movement of at least the extension side of the rod;
Sealing means provided in the flow path with an inclination angle with respect to the axial direction;
Have
An insulating layer that cuts off current to the electrorheological fluid flowing in the flow path is provided at least on the inner peripheral side of the outer cylindrical electrode among the outer peripheral side of the inner cylindrical electrode and the inner peripheral side of the outer cylindrical electrode. A cylinder device characterized by being provided.   The cylinder device according to claim 1, wherein the insulating layer is provided on both an outer peripheral side of the inner cylinder electrode and an inner peripheral side of the outer cylinder electrode.

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