JP2019007585A - Cylinder device - Google Patents

Abstract

To form a satisfactory flow of an electroviscous fluid in a flow passage by preventing positional deviation of flow passage forming means.SOLUTION: A cylinder device has: an inner cylinder electrode 3 in which an electroviscous fluid 2 that changes in fluid property according to an electric field is filled and a piston rod 9 is inserted inside; an intermediate cylinder electrode 19 (electrode cylinder 21) provided outside the inner cylinder electrode 3; and a partition wall 22 that is located between the inner cylinder electrode 3 and the electrode cylinder 21 of the intermediate cylinder electrode 19 and forms a flow passage 23 in which the electroviscous fluid 2 flows from one end side in the axial direction toward the other end side by reciprocation of the piston rod 9. Then, the electrode cylinder 21 and the partition wall 22 are formed as one piece.SELECTED DRAWING: Figure 1

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 device (buffer) using an electrorheological fluid as a functional fluid, a spiral for forming a flow path for the electrorheological fluid to flow between the inner cylinder and the electrode cylinder. The structure which provided the flow-path formation part of the shape was disclosed.

International Publication No. 2014/135183

  By the way, in the cylinder device disclosed in Patent Document 1, a spiral flow path forming portion is attached to the outer peripheral surface of the inner cylinder, and the inner cylinder to which the flow path forming portion is attached is press-fitted into the electrode cylinder. In this case, when the inner cylinder is press-fitted, there is a problem that the flow path forming portion attached to the inner cylinder may be displaced, and the flow of the electrorheological fluid becomes unstable due to the deformation of the flow path.

  An object of the present invention is to provide a cylinder device capable of improving the flow of an electrorheological fluid in a flow path by preventing a position shift of the flow path forming portion.

  According to the present invention, a cylindrical body in which an electrorheological fluid whose fluid properties are changed by an electric field is enclosed and a rod is inserted therein, an electrode cylinder provided outside the cylindrical body, the cylindrical body and the electrode And a flow path forming portion that forms a flow path in which the electrorheological fluid flows as the rod advances and retreats from one end side to the other end side in the axial direction. The cylinder and the flow path forming part are formed as an integrated body.

  ADVANTAGE OF THE INVENTION According to this invention, the position shift of a flow-path formation part can be prevented, and the flow of the electrorheological fluid in a flow path can be made favorable.

It is a longitudinal cross-sectional view which shows the shock absorber as a cylinder apparatus by embodiment. It is a longitudinal cross-sectional view which shows the intermediate | middle cylinder electrode by embodiment alone. It is a longitudinal cross-sectional view which shows the partition integrated intermediate cylinder which comprises an intermediate cylinder electrode. It is an external view which shows the core member for forming a conductive film in the inner peripheral surface of a partition integrated intermediate tube alone. It is a longitudinal cross-sectional view which shows the state which attached the core member to the partition integrated intermediate tube.

  Hereinafter, a cylinder device according to the present invention will be described with reference to FIGS. 1 to 5 by 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.

  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 and an intermediate cylinder electrode 19 which will be described later.

  The inner cylinder electrode 3 constitutes the innermost cylinder and is formed in a cylindrical shape extending in the axial direction. An electrorheological fluid 2 that is a functional fluid is sealed inside the inner cylinder electrode 3. A piston rod 9 is inserted into the inner cylinder electrode 3. The outer cylinder 4 and the intermediate 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. On the upper side of the inner cylinder electrode 3, a plurality of oil holes 3A are provided penetrating in the radial direction at intervals in the circumferential direction. The inner cylinder electrode 3 is press-fitted into an intermediate cylinder electrode 19 described later. As a result, the ridges 22A of a plurality of (for example, two) partition walls 22 provided on the intermediate cylinder electrode 19 are brought into close contact with the outer peripheral surface 3B of the inner cylinder electrode 3 in a pressed state.

  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 a negative electrode (minus electrode) of a high voltage driver 25 described later via an outer cylinder 4, a rod guide 10 and a bottom valve 13 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 that becomes a conductor (electric conductor). The outer cylinder 4 is provided outside the inner cylinder electrode 3 and the intermediate cylinder electrode 19, and a reservoir chamber A communicating with each flow path 23 is formed between the outer cylinder 4 and the intermediate 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 4A 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 intermediate cylinder electrode 19 in the outer cylinder 4 together with the seal member 12 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 flow path 23 between the inner cylinder electrode 3 and the intermediate cylinder electrode 19 and controls the viscosity of the electrorheological fluid 2 passing through the flow path 23. The generated damping force is controlled (adjusted).

  An annular reservoir chamber A is formed between the outer cylinder 4 and the intermediate 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 is transferred from the rod side oil chamber B to the flow path 23 through each oil hole 3A of the inner cylinder electrode 3 in both the reduction stroke and the extension stroke of the piston rod 9. Directly, it always circulates in one direction (direction indicated by arrow F in FIG. 1).

  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 to the outside of 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 the guide bush 11 and is formed as a stepped cylindrical body with a metal material (conductor). In this case, the rod guide 10 may be formed using a material made of an insulator, a dielectric, a high resistance, etc., for example, a hard resin material, when the valve body 14 described later is a metal material (conductor). it can. The rod guide 10 positions the upper part of the inner cylinder electrode 3 and the upper part of the intermediate cylinder electrode 19 coaxially with 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 by the guide bush 11 on the inner peripheral side thereof.

  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 is sealed (sealed) between the outer cylinder 4 and the piston rod 9 in a liquid-tight and air-tight manner by the inner peripheral side thereof being in sliding contact with the outer peripheral surface of the piston rod 9.

  The bottom valve 13 is located on the lower end side of the inner cylinder electrode 3 and 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 reduction-side 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, the valve body 14 is formed in a stepped cylindrical shape using a metal material (conductor). On the other hand, when the rod guide 10 described above is a metal material (conductor), the valve body 14 can be formed using a material made of an insulator, a dielectric, a high resistance body, etc., for example, a hard resin material. .

  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 intermediate cylinder electrode 19 in a state of being positioned in the axial direction and the radial direction. The upper holding member 17 is formed of, for example, an electrically insulating material (isolator), and electrically insulates between the inner cylinder electrode 3 and the intermediate cylinder electrode 19 and between the rod guide 10 and the intermediate cylinder electrode 19. It keeps in.

  On the other hand, the lower holding member 18 holds the lower end side of the intermediate 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 is formed between the inner cylinder electrode 3 and the intermediate cylinder electrode 19 and between the valve body 14 and the intermediate 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 flow passage 23 to communicate with the reservoir chamber A.

  Next, the configuration of the intermediate cylindrical electrode 19 that is a characteristic part of the present embodiment will be described in detail.

  The intermediate cylinder electrode 19 is provided outside the inner cylinder electrode 3, that is, between the inner cylinder electrode 3 and the outer cylinder 4. As shown in FIG. 2, the intermediate cylinder electrode 19 is configured by a partition-integrated intermediate cylinder 20 and a conductive coating 24 described later.

  The partition-integrated intermediate cylinder 20 forms a base cylinder of the intermediate cylinder electrode 19 and is formed using a material made of an insulator, a dielectric, a high resistance body, etc., for example, a hard resin material. The partition-integrated intermediate cylinder 20 is formed as a long cylindrical body using a molding means such as injection molding. The partition-integrated intermediate cylinder 20 is formed as an integral body composed of an electrode cylinder 21 and a partition wall 22 which will be described later.

  The electrode cylinder 21 is formed as a cylindrical body that is larger than the inner cylinder electrode 3 and smaller than the outer cylinder 4. That is, the inner peripheral surface 21A of the electrode cylinder 21 faces the outer peripheral surface 3B of the inner cylinder electrode 3 in the radial direction with a slight gap. A partition wall 22 to be described later is integrally provided on the inner peripheral surface 21 </ b> A of the partition wall-integrated intermediate cylinder 20. Further, a lateral hole 21 </ b> B is formed at an intermediate position in the axial direction of the electrode cylinder 21 so as to penetrate in the radial direction. The lateral hole 21B is used as an injection port when the conductive coating 24 is formed. In addition, a connection end 24A of the conductive coating 24 can be formed at the position of the lateral hole 21B. This connection end 24A is electrically connected to a positive electrode (plus electrode) of a high voltage driver 25 described later. It is connected to the.

  The upper end side of the electrode cylinder 21 is held in the vertical and radial directions with respect to the rod guide 10 via the upper holding member 17. On the other hand, the lower end side of the electrode cylinder 21 is held in a vertically and radially positioned state with respect to the valve body 14 of the bottom valve 13 via the lower holding member 18.

  The partition wall 22 constitutes a flow path forming portion and is integrally formed on the inner peripheral side of the electrode cylinder 21. The partition wall 22 is provided between the inner cylinder electrode 3 and the electrode cylinder 21 of the intermediate cylinder electrode 19. The partition wall 22 forms a later-described channel 23 having a spiral shape between the inner cylinder electrode 3 and the electrode cylinder 21 of the intermediate cylinder electrode 19. As shown in FIG. 3, the partition wall 22 is provided on the inner peripheral surface 21 </ b> A of the electrode cylinder 21 so as to extend in the axial direction of the electrode cylinder 21 while being spirally wound. One or a plurality of partition walls 22, for example, two are formed. Thereby, each partition wall 22 can form two flow paths 23 in a gap between the inner cylinder electrode 3 and the electrode cylinder 21 (conductive film 24) of the intermediate cylinder electrode 19.

  Here, each partition 22 is formed as a protrusion having a semicircular cross section, and protrudes radially inward from the inner peripheral surface 21 </ b> A of the electrode cylinder 21. Of each partition wall 22, the ridge portion 22 </ b> A, which is a tip portion that is increased inward in the radial direction, comes into contact with the outer peripheral surface 3 </ b> B of the inner cylindrical electrode 3 in a state where insulation is maintained. The film 24 is out of the formation range.

  Thus, since each partition wall 22 is integrally formed on the inner peripheral side of the electrode cylinder 21, no positional deviation occurs even when the inner cylinder electrode 3 is press-fitted into the intermediate cylinder electrode 19. Thereby, the channel area of the channel 23 to be described later can be made constant over the entire length, and the electrorheological fluid 2 can be circulated stably in each channel 23.

  The flow path 23 is provided between the outer peripheral surface 3B of the inner cylindrical electrode 3 and the inner peripheral surface 21A of the electrode cylinder 21 of the intermediate cylindrical electrode 19. The flow path 23 is formed as a plurality of, for example, two passages extending spirally by the partition walls 22. In each flow path 23, the electrorheological fluid 2 flows from the upper end side toward the lower end side. Each flow path 23 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 in the direction of the flow of the electrorheological fluid 2 indicated by the arrow F in FIG. 1, the shock absorber 1 moves from the rod side oil chamber B through the oil hole 3 </ b> A in both the reduction stroke and the extension stroke of the piston 6. The electrorheological fluid 2 flows into the flow path 23. The electrorheological fluid 2 that has flowed into each flow path 23 is moved forward and backward by the forward / backward movement of the piston rod 9 in the inner cylinder electrode 3 (that is, while the reduction stroke and the expansion stroke are repeated). It flows from the upper end side in the axial direction toward the lower end side. Then, the electrorheological fluid 2 that has flowed into each flow path 23 flows out into the reservoir chamber A via the oil path 18 </ b> A of the lower holding member 18.

  The conductive coating 24 is provided on the inner peripheral surface 21 </ b> A of the electrode cylinder 21. The conductive coating 24 is formed in a thin film by attaching, for example, a conductive paint to the inner peripheral surface 21A of the electrode cylinder 21. The conductive coating 24 is formed with a film thickness dimension of about 0.5 to 0.8 mm, for example. The conductive coating 24 is provided on the inner peripheral side of the electrode cylinder 21 excluding the ridge 22A so that the conductive paint does not adhere to the ridge 22A of each partition wall 22 by using a manufacturing method described later. it can. In the conductive coating 24, a connection end 24 </ b> A is formed in the horizontal hole 21 </ b> B of the electrode cylinder 21. The connection end 24A is electrically connected to a positive electrode (plus electrode) of a high voltage driver 25 described later.

  Here, in each flow path 23 divided | segmented by each partition 22, resistance is provided to the electrorheological fluid 2 which distribute | circulates, when piston 6 slides in the inner cylinder electrode 3. FIG. For this purpose, the intermediate cylinder electrode 19 is connected to, for example, a high voltage driver 25 that generates a high voltage via a battery (not shown) serving as a power source. The high voltage driver 25 serves as a voltage supply unit (electric field supply unit), and the intermediate cylinder electrode 19 serves as an electrode (electrode) that applies an electric field (voltage) to the electrorheological fluid 2 in each flow path 23. In this case, both end sides of the intermediate 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) of the high voltage driver 25 through the rod guide 10, the bottom valve 13, the bottom cap 5, the outer cylinder 4, and the like.

  Next, an example of a manufacturing method when the conductive coating 24 is provided on the inner peripheral surface 21A of the electrode cylinder 21 will be described with reference to FIGS.

  In the manufacturing method of the conductive coating 24, in order to keep the inner cylindrical electrode 3 and the intermediate cylindrical electrode 19 in an insulated state, the ridge portion 22A at the tip where each partition wall 22 contacts the inner cylindrical electrode 3 is excluded. Therefore, it is necessary to form the conductive coating 24.

  First, the core member 26 used in the method for manufacturing the conductive coating 24 will be described (see FIG. 4). The core member 26 is formed as a columnar body (or cylindrical body) having a smaller diameter than the inner peripheral surface 21A of the electrode cylinder 21 by the thickness of the conductive coating 24. Further, on the outer peripheral surface 26 </ b> A of the core member 26, a spiral groove portion 26 </ b> B into which the ridge portion 22 </ b> A of each partition wall 22 is screwed is formed. This groove part 26B covers (masks) the ridge part 22A of the partition wall 22 so that the conductive paint does not adhere.

  An example of a method for manufacturing the conductive coating 24, that is, an operation method for manufacturing the intermediate cylinder electrode 19, will be described.

  When the partition-integrated intermediate cylinder 20 is manufactured by injection molding or the like, a core member 26 is inserted into the partition-integrated intermediate cylinder 20 as shown in FIG. At this time, the groove member 26B of the core member 26 is aligned with each partition wall 22 of the partition wall-integrated intermediate cylinder 20, and the core member 26 is rotated while rotating, for example, counterclockwise along the spiral direction of each partition wall 22. Push into the partition-integrated intermediate tube 20. Thereby, a gap corresponding to the film thickness dimension of the conductive coating 24 can be formed between the outer peripheral surface 26 </ b> A of the core member 26 and the inner peripheral surface 21 </ b> A of the electrode cylinder 21. On this, the groove part 26 </ b> B of the core member 26 can cover the ridge part 22 </ b> A of the partition wall 22.

  When the core member 26 is inserted into the partition wall-integrated intermediate tube 20, the partition wall-integrated intermediate tube 20 and the core from the partition wall-integrated intermediate tube 20, the end of the core member 26, and the lateral hole 21 </ b> B of the electrode tube 21. Conductive paint is injected into the gap with the member 26. When the injected conductive paint is solidified, the core member 26 is pulled out of the partition wall-integrated intermediate cylinder 20 while rotating the core member 26 clockwise. Thereby, as shown in FIG. 2, the conductive coating 24 can be provided on the inner peripheral surface 21 </ b> A of the electrode cylinder 21 avoiding the ridge portion 22 </ b> A of each partition wall 22, and the intermediate cylinder electrode 19 can be manufactured. In the method of manufacturing the intermediate cylinder electrode 19 (conductive film 24), a connection end 24A for connecting the high voltage driver 25 can be provided at the same time.

  Next, when the conductive coating 24 is provided on the intermediate cylinder electrode 19, the inner cylinder electrode 3 is inserted into the intermediate cylinder electrode 19. At this time, each partition wall 22 is integrally formed with the electrode cylinder 21 of the partition wall-integrated intermediate cylinder 20, so that each partition wall 22 is not displaced.

  The shock absorber 1 according to the present 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 on the wheel side (axle side). Install. When the vehicle is running, if the vibration in the vertical direction is generated due to unevenness of the road surface, the piston rod 9 is displaced so as to extend and contract from the outer cylinder 4. At this time, by generating a potential difference in each flow path 23 using a high voltage driver 25 according to a command from the controller, and controlling the viscosity of the electrorheological fluid 2 passing through each flow path 23, the shock absorber 1 is generated. Adjust the damping force variably.

  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 flow paths 23 through the oil holes 3 </ b> A 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 has entered the inner cylinder electrode 3 flows from the rod-side oil chamber B into each flow path 23 through each oil hole 3A of the inner cylinder electrode 3.

  Accordingly, in any case (both during the expansion stroke and the reduction stroke), the electrorheological fluid 2 that has flowed into each flow path 23 is caused by a potential difference (between the inner cylinder electrode 3 and the intermediate cylinder electrode 19) between the flow paths 23. Pass through the respective flow paths 23 toward the outlet side (lower side) with a viscosity corresponding to the potential difference between the two flow paths 23 and flow out from each flow path 23 to the reservoir chamber A through the oil path 18A of the lower holding member 18. At this time, the shock absorber 1 can generate a damping force corresponding to the viscosity of the electrorheological fluid 2 that passes through each flow path 23 to buffer (attenuate) the vertical vibration of the vehicle.

  Thus, in the present embodiment, the electrode cylinder 21 and each partition wall 22 of the partition wall-integrated intermediate cylinder 20 are formed as an integrated object. Therefore, when the inner cylinder electrode 3 is press-fitted into the partition-integrated intermediate cylinder 20, it is possible to prevent the partition walls 22 from being displaced and to improve the flow of the electrorheological fluid 2 in each flow path 23. Can do.

  The partition-integrated intermediate cylinder 20 of the intermediate cylinder electrode 19 is formed using a hard resin material made of an insulator, a dielectric, a high resistance body, or the like. Therefore, since it is not necessary to provide an insulating film on the outer peripheral surface of the partition wall-integrated intermediate cylinder 20, it is possible to prevent a situation in which a part of the insulating film is peeled off and mixed into the electrorheological fluid 2.

  In the embodiment, the case where the conductive coating 24 is formed into a thin film by attaching a conductive paint to the inner peripheral surface 21 </ b> A of the electrode cylinder 21 has been described as an example. However, the present invention is not limited to this, and the conductive coating 24 is formed by, for example, attaching a conductive film formed by forming a conductor in a thin film shape to the inner peripheral surface 21 </ b> A of the electrode cylinder 21 so as to avoid each partition wall 22. May be formed.

  Further, in the embodiment, the partition-integrated intermediate cylinder 20 is described by taking as an example a case in which the resin cylinder is used and the electrode cylinder 21 and the partition 22 are integrally formed by a molding means such as injection molding. However, the present invention is not limited to this. For example, the partition wall-integrated intermediate cylinder 20 may be formed by using a machining means such as a cutting process or a 3D printer.

  In the embodiment, the core member 26 used in the method of manufacturing the conductive coating 24 is formed with a spiral groove portion 26B on the outer peripheral surface 26A so as to correspond to the partition wall 22 formed as a spirally extending protrusion. In addition, the core member 26 is described as being inserted into and removed from the partition-integrated intermediate cylinder 20 while rotating in accordance with the spiral shape. However, the present invention is not limited to this, and for example, the partition may be formed in other shapes such as a meandering shape and a zigzag shape. In this case, by forming the core member with an elastic body, the core member can be brought into close contact with the partition wall, and the core member can be linearly inserted and removed with respect to the partition-integrated intermediate cylinder.

  In the 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 the embodiment, the case where the shock absorber 1 is configured to be arranged in the vertical direction has been described as an example. 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 the 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 the 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 cylindrical body in which an electrorheological fluid whose fluid properties are changed by an electric field is enclosed, a rod is inserted therein, an electrode cylinder provided outside the cylindrical body, the cylindrical body, A flow path forming portion that is located between the electrode cylinder and forms a flow path through which the electrorheological fluid flows by the forward and backward movement of the rod from one end side to the other end side in the axial direction, and The electrode cylinder and the flow path forming part are formed as a single body.

  As a second aspect, in the first aspect, the electrode cylinder and the flow path forming portion are integrally formed using an insulating material, and the flow path forming section is formed on an inner peripheral surface of the electrode cylinder. It is characterized in that a conductive film is provided so as to avoid the above.

  As a third aspect, in the first aspect, the flow path forming portion is a protrusion that is integrally formed on an inner peripheral surface of the electrode cylinder and extends spirally along the inner peripheral surface, and the cylindrical body Is characterized in that the outer peripheral surface is press-fitted into the inner peripheral side of the electrode cylinder in a state where the outer peripheral surface is in contact with the protrusion.

1 Shock absorber (cylinder device)
2 Electrorheological fluid 3 Inner cylinder electrode (cylinder)
3B Outer peripheral surface 4 Outer cylinder 9 Piston rod (rod)
19 Intermediate tube electrode 20 Bulkhead integrated intermediate tube 21 Electrode tube 21A Inner peripheral surface 22 Bulkhead (flow path forming portion)
22A Ridge part 23 Channel 24 Conductive coating

Claims (3)

A cylindrical body in which an electrorheological fluid whose fluid properties change by an electric field is enclosed, and a rod is inserted therein;
An electrode cylinder provided outside the cylinder;
A flow path forming portion that is located between the cylindrical body and the electrode cylinder and forms a flow path in which the electrorheological fluid flows by the forward and backward movement of the rod from one end side to the other end side in the axial direction;
Have
The cylinder device, wherein the electrode cylinder and the flow path forming portion are formed as a single body. The electrode cylinder and the flow path forming part are integrally formed using an insulating material,
The cylinder device according to claim 1, wherein a conductive coating is provided on an inner peripheral surface of the electrode cylinder so as to avoid the flow path forming portion. The flow path forming portion is a protrusion that is integrally formed on the inner peripheral surface of the electrode cylinder and extends spirally along the inner peripheral surface,
2. The cylinder device according to claim 1, wherein the cylindrical body is press-fitted into an inner peripheral side of the electrode cylinder in a state where an outer peripheral surface thereof is in contact with the protrusion.

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