JP6986456B2 - Cylinder device - Google Patents

Description

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

Generally, a vehicle such as an automobile is provided with a cylinder device represented by a hydraulic shock absorber between the vehicle body (upper spring) side and each wheel (unsprung) side. Here, in Patent Document 1, in a damper (buffer) using an electrorheological fluid whose properties change due to an electric field, the electrorheological fluid flows in a flow path between an inner cylinder electrode and an intermediate cylinder electrode. The configuration is disclosed.

International Publication No. 2014/135183

By the way, in the cylinder device of Patent Document 1, the electrorheological fluid in the inner cylinder electrode flows out from the lateral hole formed in the inner cylinder electrode and collides with the inner peripheral surface of the intermediate cylinder electrode. As a result, the electrorheological fluid turns in various directions and flows toward the flow path between the inner cylinder electrode and the intermediate cylinder electrode, so that the pressure loss may increase and the damping force may increase.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a cylinder device capable of stabilizing damping force characteristics by smoothly circulating an electrorheological fluid. To do.

The present invention is a cylinder device in which an electrically viscous fluid whose properties change due to an electric field is enclosed and a rod is inserted inside. The inner cylinder electrode and the outer periphery of the inner cylinder electrode, which are electrodes having different potentials from each other, An intermediate cylinder electrode provided, an outer cylinder provided on the outer periphery of the intermediate cylinder electrode, a closing member provided at one end of the inner cylinder electrode, the intermediate cylinder electrode, and the outer cylinder, the inner cylinder electrode, and the said. The intermediate cylinder electrode is formed between the intermediate cylinder electrode and has a flow path through which the electrically viscous fluid flows due to movement of at least the extension side of the rod from one end side to the other end side in the axial direction. An enlarged diameter portion having an expanded outer diameter is formed on one end side where the closing member is provided, the closing member supports the rod, and one end in the axial direction is provided on the outer cylinder. The other end is press-fitted outward so as to cover one end of the inner cylinder electrode, and the annular side portion extending in the axial direction covering one end of the inner cylinder electrode of the closing member is formed by the inner cylinder electrode. One or one that communicates with the inner cylinder electrode on one end side and extends axially toward the flow path, and guides the electroviscous fluid in the inner cylinder electrode to the flow path by moving at least the extension side of the rod. A plurality of passage holes are formed, and an insulating member is provided between the enlarged diameter portion and the annular side portion.

According to the cylinder device of the present invention, the electrorheological fluid can be smoothly circulated, and stable damping force characteristics can be obtained.

It is a vertical sectional view which shows the cylinder apparatus by 1st Embodiment of this invention. FIG. 3 is an enlarged vertical sectional view showing a rod guide, a passage forming member, an insulating member, and the like in FIG. 1. It is a front view which shows the state which the electrorheological fluid flows out from a passage hole of a passage forming member toward a passage. It is sectional drawing which shows the passage forming member enlarged. It is a vertical sectional view which shows the passage forming member by 2nd Embodiment of this invention. It is the same front view as FIG. 3 which shows the state which flows out from the passage hole of the passage forming member in FIG. 5 toward a passage. It is a vertical sectional view which shows the passage forming member by the 1st modification of this invention. It is the same vertical sectional view as FIG. 2 which shows the closing member by the 2nd modification of this invention.

Hereinafter, a case where the cylinder device of the present invention is applied to a vehicle such as a four-wheeled vehicle will be described as an example, and will be described with reference to the accompanying drawings.

1 to 4 show a first embodiment of the present invention. In FIG. 1, the cylinder device 1 is configured as a damping force adjusting type hydraulic shock absorber (semi-active damper) using an electrorheological fluid 2 as a hydraulic oil to be sealed inside. The cylinder device 1 constitutes a suspension device for a vehicle together with a suspension spring (not shown) including, for example, a coil spring. In the following description, the one end side in the axial direction of the cylinder device 1 is referred to as the "upper end" side, and the other end side in the axial direction is described as the "lower end" side. The "lower end" side may be used, and the other end side in the axial direction may be the "upper end" side.

The cylinder device 1 includes an inner cylinder electrode 3, an outer cylinder 4, a piston 6, a piston rod 9, a bottom valve 10, a lower spacer 14, an intermediate cylinder electrode 15, a flow path forming member 16, a rod guide 19, and a passage forming member 22. It is configured to include the upper spacer 27.

The inner cylinder electrode 3 is formed as a cylindrical body extending in the axial direction, and an electrorheological fluid 2 is enclosed therein. Further, a piston rod 9 is inserted inside the inner cylinder electrode 3, and a piston rod 9 is inserted between the outer cylinder 4 and the inner cylinder electrode 3 and the outer cylinder 4 on the outside (diametrically outside) of the inner cylinder electrode 3. The intermediate cylinder electrode 15 is provided so as to be coaxial with the intermediate cylinder electrode 15.

The lower end 3A side of the inner cylinder electrode 3 is fitted and attached to the valve body 11 of the bottom valve 10, and the upper end 3B side is fitted (press-fitted) to the passage forming member 22 and attached. Further, a plurality of (for example, four) flow path forming members 16 described later are spirally wound and attached to the outer peripheral side of the inner cylinder electrode 3. The inner cylinder electrode 3 is made of a material that serves as a conductor, and is electrically connected to the negative electrode of the battery 28 via an outer cylinder 4, a bottom valve 10, a closing member 18, and the like, which will be described later.

The outer cylinder 4 forms the outer shell of the cylinder device 1, and is formed as a cylinder by a material serving as a conductor. The outer cylinder 4 is provided on the outer peripheral side (diametrically outside) of the inner cylinder electrode 3 and the intermediate cylinder electrode 15, and forms a reservoir chamber A communicating with the flow path 17 between the inner cylinder electrode 3 and the intermediate cylinder electrode 15. .. In this case, the lower end side of the outer cylinder 4 is a closed end due to the bottom cap 5 being fixed by using a welding means or the like.

On the other hand, the upper end side of the outer cylinder 4 is an open end. For example, a crimped portion 4A is formed on the open end side of the outer cylinder 4 by bending inward in the radial direction. The caulking portion 4A holds the outer peripheral side of the annular plate body 21A of the sealing member 21 in a retaining state.

Here, the inner cylinder electrode 3 and the outer cylinder 4 form a cylinder, and an electrorheological fluid 2 (ERF) is enclosed in the cylinder. In addition, in FIG. 1 and FIG. 2, the enclosed electrorheological fluid 2 is represented by colorless and transparent.

The properties of the electrorheological fluid 2 change depending on the electric field (voltage). That is, the viscosity of the electrorheological fluid 2 changes according to the applied voltage. The electrorheological fluid 2 is composed of a base oil (base oil) made of, for example, silicon oil, and particles (fine particles) whose viscosity is variable according to changes in the electric field mixed (dispersed) in the base oil. There is.

The cylinder device 1 generates a potential difference in the flow path 17 between the inner cylinder electrode 3 and the intermediate cylinder electrode 15, and controls the viscosity of the electrorheological fluid 2 passing through the flow path 17, thereby generating damping force. Can be controlled (adjusted).

An annular reservoir chamber A is formed between the intermediate cylinder electrode 15 and the outer cylinder 4. The reservoir chamber A is filled with a gas that becomes a working gas together with the electrorheological fluid 2. This gas may be air in an atmospheric pressure state, or a gas such as compressed nitrogen gas may be used. The gas in the reservoir chamber A is compressed to compensate for the approaching volume of the piston rod 9 when the piston rod 9 is contracted (contracting stroke).

The piston 6 is slidably provided in the inner cylinder electrode 3. The piston 6 divides 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. A plurality of oil passages 6A and 6B that allow the rod-side oil chamber B and the bottom-side oil chamber C to communicate with each other are formed in the piston 6 so as to be separated from each other in the circumferential direction. Here, the cylinder device 1 has a uniflow structure. Therefore, the electrorheological fluid 2 in the inner cylinder electrode 3 is always directed toward the flow path 17 from the rod-side oil chamber B through the passage hole 26 described later in both the contraction stroke and the expansion stroke of the piston rod 9. It circulates in the direction (direction of arrow F1 in FIG. 1).

In order to realize such a uniflow structure, a valve is opened on the upper end surface of the piston 6 when, for example, the piston 6 is slidably displaced downward in the inner cylinder electrode 3 in the contraction stroke (shrinkage stroke) of the piston rod 9. In other cases, a contraction-side check valve 7 that closes the valve is provided. The contraction-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 the electrorheological fluid 2 in the opposite direction. Prevents the flow. That is, the contraction-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.

For example, a disc valve 8 on the extension side is provided on the lower end surface of the piston 6. In the extension side disc valve 8, when the piston 6 slides upward in the inner cylinder electrode 3 in the extension stroke (extension stroke) of the piston rod 9, the pressure in the rod side oil chamber B sets the relief set pressure. When it exceeds, the valve is opened, and the pressure at this time is relieved to the bottom side oil chamber C side via each oil passage 6B.

The piston rod 9 as a rod has an axial direction inside the inner cylinder electrode 3 (the axial direction of the inner cylinder electrode 3 and the outer cylinder 4, that is, the same direction as the central axis of the cylinder device 1, and the upper and lower directions in FIG. 1). Extends to. The lower end of the piston rod 9 is connected (fixed) to the piston 6 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. In this case, the piston 6 is fastened to the lower end side of the piston rod 9 by using a nut 9A or the like. On the other hand, the upper end side of the piston rod 9 projects to the outside via the closing member 18. It should be noted that the lower end of the piston rod 9 may be further extended to be a double-rod type shock absorber protruding outward from the bottom portion (for example, the bottom cap 5) side.

On the lower end 3A side of the inner cylinder electrode 3, a bottom valve 10 is provided located between the inner cylinder electrode 3 and the bottom cap 5. The bottom valve 10 communicates or shuts off the bottom side oil chamber C and the reservoir chamber A. For this purpose, the bottom valve 10 includes a valve body 11, an extension check valve 12, and a disc valve 13. The valve body 11 partitions the reservoir chamber A and the bottom side oil chamber C between the bottom cap 5 and the inner cylinder electrode 3.

The valve body 11 is formed with oil passages 11A and 11B that allow the reservoir chamber A and the bottom side oil chamber C to communicate with each other at intervals in the circumferential direction. A step portion 11C is formed on the upper surface side of the valve body 11, and the lower end 3A of the inner cylinder electrode 3 is fitted and fixed to the step portion 11C. Further, an annular lower spacer 14 is fitted and attached to the step portion 11C on the outer peripheral side of the inner cylinder electrode 3. Here, when the rod guide 19 described later is a metal material (conductor), the valve body 11 can be formed by using a material made of an insulator, a dielectric, a high resistor, or the like, for example, a hard resin material. can.

The extension side check valve 12 is provided, for example, on the upper surface side of the valve body 11. The extension-side check valve 12 opens when the piston 6 slides upward during the extension stroke of the piston rod 9, and closes at other times. The extension-side check valve 12 allows the electrorheological fluid 2 in the reservoir chamber A to flow in each oil passage 11A toward the bottom-side oil chamber C, and the electrorheological fluid 2 flows in the opposite direction. To prevent. That is, the extension-side check valve 12 allows only the flow of the electrorheological fluid 2 from the reservoir chamber A side to the bottom-side oil chamber C side.

The disc valve 13 on the reduction side is provided, for example, on the lower surface side of the valve body 11. The disc valve 13 on the reduction side opens when the pressure in the oil chamber C on the bottom side exceeds the relief set pressure when the piston 6 slides and displaces downward in the reduction stroke of the piston rod 9, and the pressure at this time. Is relieved to the reservoir chamber A side via each oil passage 11B.

The lower spacer 14 holds the lower end side of the intermediate cylinder electrode 15 in a state of being positioned in the axial direction and the radial direction. The lower spacer 14 is formed as an insulator or a high resistor by using, for example, an electrically insulating material (isolator), and is between the inner cylinder electrode 3 and the intermediate cylinder electrode 15, the valve body 11 and the intermediate cylinder electrode 15. The spaces are kept electrically insulated from each other. Further, the lower spacer 14 is formed with a plurality of oil passages 14A that allow the flow path 17 to communicate with the reservoir chamber A.

The intermediate cylinder electrode 15 is provided on the outer peripheral side (diametrically outside) of the inner cylinder electrode 3 so as to surround the inner cylinder electrode 3. The intermediate cylinder electrode 15 is formed by a pressure tube located between the inner cylinder electrode 3 and the outer cylinder 4 and extending in the axial direction. The intermediate cylinder electrode 15 is made of a material (for example, a metal material) that serves as a conductor, and is electrically connected to the positive electrode of the battery 28, which will be described later. A flow path 17 is formed between the intermediate cylinder electrode 15 and the inner cylinder electrode 3 so that the lower end side communicates with the reservoir chamber A and the upper end side communicates with the rod side oil chamber B.

The intermediate cylinder electrode 15 is formed by a small diameter portion 15A extending axially from the lower spacer 14 toward the upper end side and a diameter expansion portion 15B whose diameter is expanded from the upper end of the small diameter portion 15A toward the outer cylinder 4. There is. The lower end side of the small diameter portion 15A of the intermediate cylinder electrode 15 is held in the upward, downward and radial directions with respect to the valve body 11 of the bottom valve 10 via the lower spacer 14. On the other hand, the enlarged diameter portion 15B of the intermediate cylinder electrode 15 is formed on the upper end side where the closing member 18 of the intermediate cylinder electrode 15 is provided. The enlarged diameter portion 15B of the intermediate cylinder electrode 15 is held in a state of being positioned in the upward, downward, and radial directions with respect to the closing member 18 via the upper spacer 27 described later.

A plurality of (for example, four) flow path forming members 16 are provided on the outer peripheral surface of the inner cylinder electrode 3 so as to extend spirally in the upward and downward directions. These flow path forming members 16 are fixed to the outer peripheral surface of the inner cylinder electrode 3 in a clockwise direction from the upper end side 16A to the lower end side 16B. Each flow path forming member 16 is formed as a ridge protruding from the outer peripheral surface of the inner cylinder electrode 3, and the tip portion of the ridge is in contact with the inner peripheral surface of the small diameter portion 15A of the intermediate cylinder electrode 15. As a result, each flow path forming member 16 forms a plurality of (for example, four) flow paths 17 between the inner cylinder electrode 3 and the intermediate cylinder electrode 15. Each flow path forming member 16 is made of a polymer material having elasticity such as elastomer and having electrical insulating properties, for example, synthetic rubber. Each flow path forming member 16 is fixed (adhered) to the inner cylinder electrode 3 by using, for example, an adhesive.

Each flow path 17 is formed between the inner cylinder electrode 3 and the intermediate cylinder electrode 15 by being spirally divided by each flow path forming member 16. The electrorheological fluid 2 in the inner cylinder electrode 3 flows in each flow path 17 from the upper side, which is one end side in the axial direction, to the lower side, which is the other end side, due to the movement of the piston rod 9. Each flow path 17 is always in communication with the rod-side oil chamber B in the inner cylinder electrode 3 via the passage hole 26 of the passage forming member 22, which will be described later, on the upper end 3B side of the inner cylinder electrode 3.

That is, as shown by the arrow F1 in the flow direction of the electrorheological fluid 2 in FIG. 2, the electrorheological fluid 2 has the upper end of the inner cylinder electrode 3 from the rod-side oil chamber B in both the contraction stroke and the expansion stroke of the piston 6. It flows beyond 3B into each flow path 17 through each passage hole 26. When the piston rod 9 advances and retreats in the inner cylinder electrode 3 (that is, while repeating the contraction stroke and the expansion stroke), the electrorheological fluid 2 flowing into each flow path 17 advances and retreats in each flow path 17. Flows from the upper end side to the lower end side.

The electrorheological fluid 2 flows into each flow path 17 from the inside of the inner cylinder electrode 3 due to the movement of the piston rod 9 on the extension side and the movement on the contraction side, and flows into each flow path 17 from one end side in the axial direction to the other end. It flows toward the side. Then, the electrorheological fluid 2 flowing through each flow path 17 flows out from the lower end side of the intermediate cylinder electrode 15 to the reservoir chamber A through the oil passage 14A of the lower spacer 14.

In each flow path 17, resistance is applied to the electrorheological fluid 2 flowing by sliding the piston 6 in the inner cylinder electrode 3. That is, a potential difference is generated in each flow path 17 according to the voltage applied to the intermediate cylinder electrode 15, and the viscosity of the electrorheological fluid 2 changes. In this case, the cylinder device 1 changes the characteristic (damping force characteristic) of the generated damping force from a soft characteristic (soft characteristic) to a hard characteristic as the voltage applied to the intermediate cylinder electrode 15 increases. It can be continuously adjusted to (hardness characteristics). The cylinder device 1 may be capable of adjusting the damping force characteristics in two stages or three or more stages even if the damping force characteristics are not continuous.

Next, the closing member 18 that closes the upper end side of the reservoir chamber A and the rod side oil chamber B will be described.

The closing member 18 is provided at the upper end of the inner cylinder electrode 3, the intermediate cylinder electrode 15, and the outer cylinder 4. The closing member 18 supports the piston rod 9, the upper end side in the axial direction is provided on the outer cylinder 4, and the lower end side in the axial direction is press-fitted outward so as to cover the upper end 3B of the inner cylinder electrode 3. The closing member 18 positions the upper portion of the inner cylinder electrode 3 and the upper portion of the intermediate cylinder electrode 15 at the center of the outer cylinder 4. The closing member 18 includes a rod guide 19 and a passage forming member 22.

The upper end side of the rod guide 19 is provided on the outer cylinder 4, and the lower end side is press-fitted into the passage forming member 22 described later. The rod guide 19 is formed as a stepped cylinder and closes the upper end side of the inner cylinder electrode 3 and the outer cylinder 4. The rod guide 19 supports the piston rod 9, and is formed as a tubular body having a predetermined shape by subjecting, for example, a metal material, a hard resin material, or the like to a molding process, a cutting process, or the like. In this case, when the valve body 11 is a metal material (conductor), the rod guide 19 can be formed by using a material made of an insulator, a dielectric, a high resistor, or the like, for example, a resin material. The rod guide 19 guides (guides) the piston rod 9 so as to be slidable in the axial direction on the inner peripheral side thereof.

Here, the rod guide 19 is located on the upper side of the large diameter portion 19A inserted into the inner peripheral side of the outer cylinder 4, and is located on the lower end side of the large diameter portion 19A and is located on the inner peripheral side of the inner cylinder electrode 3. It is formed by a small diameter portion 19B inserted into the. A guide bush 20 that guides the piston rod 9 so as to be slidable in the axial direction is inserted on the inner peripheral side of the small diameter portion 19B of the rod guide 19. The guide bush 20 is formed, for example, by applying a tetrafluoride ethylene coating to the inner peripheral surface of a metal cylinder. Further, on the outer peripheral side of the small diameter portion 19B, a passage forming member 22 and an upper spacer 27, which will be described later, are provided on the lower side of the large diameter portion 19A so as to overlap each other in the radial direction.

An annular sealing member 21 is provided between the large diameter portion 19A of the rod guide 19 and the caulking portion 4A of the outer cylinder 4. The sealing member 21 has an annular plate body 21A made of a metallic annular plate body that is in contact with the upper surface of the large diameter portion 19A, and elasticity fixed to the inner diameter side of the annular plate body 21A by means such as seizure. It is configured to include an elastic body 21B made of a resin material having the above. The inner peripheral side of the elastic body 21B is in sliding contact with the outer peripheral surface of the piston rod 9, so that the sealing member 21 is liquid-tightly and airtightly sealed between the elastic body 21B and the piston rod 9. Further, a gas chamber D communicating with the reservoir chamber A is formed between the rod guide 19 and the seal member 21.

The passage forming member 22 constitutes a part of the closing member 18, and is provided between the inner cylinder electrode 3 and the upper spacer 27 described later. The passage forming member 22 is formed in a cylindrical shape by, for example, a metal material harder than the rod guide 19. That is, the passage forming member 22 and the rod guide 19 are formed of a metal material in which the passage forming member 22 is less deformed with respect to the rod guide 19 when a force is applied in the axial direction. As a result, the passage forming member 22 can receive the axial force and the residual axial force acting on the inner cylinder electrode 3 when the cylinder device 1 is assembled, so that the material of the rod guide 19 is changed, the surface is processed, and the like. The strength of the closing member 18 can be increased without applying the above.

The passage forming member 22 includes a rod guide insertion portion 23 into which the small diameter portion 19B of the rod guide 19 is inserted, an inner cylinder electrode insertion portion 24 into which the upper end 3B side of the inner cylinder electrode 3 is inserted, and an inner cylinder electrode insertion portion. It is configured to include a plurality of (for example, four) passage holes 26 formed apart from each other in the circumferential direction of the 24.

As shown in FIGS. 2 and 4, the rod guide insertion portion 23 constitutes the upper side of the passage forming member 22, and the small diameter portion 19B of the rod guide 19 is press-fitted into the inner peripheral circumference 23A. On the other hand, the inner cylinder electrode insertion portion 24 constitutes the lower side of the passage forming member 22, and the inner cylinder electrode 3 is press-fitted into the inner peripheral 24A. A step portion 25 is formed on the inner circumference 24A of the inner cylinder electrode insertion portion 24, and the upper end 3B of the inner cylinder electrode 3 is in contact with the step portion 25. That is, the inner cylinder electrode insertion portion 24 constitutes an annular side portion extending in the axial direction covering the upper end 3B portion (one end portion) of the inner cylinder electrode 3.

The passage hole 26 is provided in the inner cylinder electrode insertion portion 24 extending in the axial direction so as to cover the upper end 3B portion of the inner cylinder electrode 3 in the passage forming member 22. Specifically, a plurality (for example, four) of the passage holes 26 are formed on the inner peripheral 24A side of the inner cylinder electrode insertion portion 24 so as to be separated in the circumferential direction. Each passage hole 26 communicates with the inner cylinder electrode 3 on the upper end 3B portion side of the inner cylinder electrode 3 and extends axially toward the flow path 17, and the movement of the piston rod 9 on the extension side and the contraction side causes the piston rod 9 to move. The electrorheological fluid 2 in the inner cylinder electrode 3 is guided to the flow path 17.

Each of the passage holes 26 has a radial passage 26A extending radially outward from the inner circumference 24A of the inner cylinder electrode insertion portion 24 at a position corresponding to the step portion 25, and the radial passage 26A toward the flow path 17. It consists of an axial passage 26B extending in the axial direction. As a result, each passage hole 26 communicates the inside of the inner cylinder electrode 3 (rod side oil chamber B) with the flow path 17 formed between the inner cylinder electrode 3 and the intermediate cylinder electrode 15.

Therefore, due to the movement of the piston rod 9 on the extension side or the contraction side, the electrorheological fluid 2 in the inner cylinder electrode 3 flows out to the radial passage 26A of each passage hole 26 so as to overflow from the upper end 3B of the inner cylinder electrode 3. , Flow out from the axial passage 26B toward the flow path 17. In this case, since the axial passage 26B of each passage hole 26 extends in the same axial direction as the inner cylinder electrode 3 and the intermediate cylinder electrode 15, the electrorheological fluid 2 smoothly flows out toward each flow path 17. And the pressure loss can be reduced. Further, since each passage hole 26 can rectify the electrorheological fluid 2 flowing from the inner cylinder electrode 3 toward the flow path 17, the generation of bubbles can be reduced. Thereby, the damping force characteristic of the cylinder device 1 can be stabilized.

At the end of the axial passage 26B on the flow path side, a passage-side inclined surface 26B1 that inclines from the radial inner peripheral side toward the radial outer peripheral side is formed. That is, the axial passage 26B is a passage whose diameter is expanded outward in the radial direction from the radial passage 26A side toward the flow path 17 side by the passage side inclined surface 26B1. Therefore, the aisle-side inclined surface 26B1 can, for example, guide (make it easy to escape) the air bubbles generated in the aisle-side inclined surface 26B1 upward along the aisle-side inclined surface 26B1. As a result, it is possible to reduce the occurrence of air bubble accumulation on the lower end side of the passage forming member 22, and thus it is possible to improve the responsiveness of the cylinder device 1.

The upper spacer 27 as an insulating member is provided between the enlarged diameter portion 15B of the intermediate cylinder electrode 15 and the inner cylinder electrode insertion portion 24 of the passage forming member 22. The upper spacer 27 is held on the closing member 18 side in a state where the upper end side (diameter expansion portion 15B side) of the intermediate cylinder electrode 15 is positioned in the axial direction and the radial direction. Like the lower spacer 14, the upper spacer 27 is formed as an insulator or a high resistance body by using, for example, an electrically insulating material (isolator), and is formed between the inner cylinder electrode 3 and the intermediate cylinder electrode 15 and a closing member. The space between 18 and the intermediate cylinder electrode 15 is kept electrically insulated from each other.

As shown in FIG. 2, an insulating member-side inclined surface 27A that inclines from the radial inner peripheral side toward the radial outer peripheral side is formed at the flow path side end portion of the upper spacer 27. The insulating member-side inclined surface 27A can, for example, guide (make it easier to pull out) air bubbles generated in the flow path 17 upward (passage hole 26) along the insulating member-side inclined surface 27A. As a result, it is possible to reduce the occurrence of air bubble accumulation on the lower end side of the upper spacer 27, so that the responsiveness of the cylinder device 1 can be improved.

The battery 28 has a positive electrode connected to the intermediate cylinder electrode 15 via a high voltage driver (not shown). The battery 28 is a voltage supply unit (electric field supply unit) to the intermediate cylinder electrode 15. As a result, the battery 28 softens the characteristic of the generated damping force (damping force characteristic) according to the magnitude of the voltage (electric field) applied to the electrorheological fluid 2 (electrorheological fluid) flowing in the flow path 17. (Soft) characteristics (soft characteristics) and hard (hard) characteristics (hard characteristics) are continuously adjusted.

The battery 28 (and the high voltage driver) becomes a voltage supply unit (electric field supply unit), and the intermediate cylinder electrode 15 becomes an electrode (electrode) that applies an electric field (voltage) to the electrorheological fluid 2 in the flow path 17. In this case, both ends of the intermediate cylinder electrode 15 are electrically insulated by the electrically insulating lower spacer 14 and the upper spacer 27. On the other hand, the inner cylinder electrode 3 is connected to the negative electrode (ground) via the closing member 18, the bottom cap 5, the outer cylinder 4, the high voltage driver, and the like. The high voltage driver boosts the DC voltage output from the battery 28 based on a command (high voltage command) output from a controller (not shown) for variably adjusting the damping force of the cylinder device 1. It is supplied (output) to the intermediate cylinder electrode 15.

The cylinder device 1 according to the first embodiment has the above-mentioned configuration, and its operation will be described next.

When mounting the cylinder device 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 attached to the wheel side (axle side). .. When the vehicle travels, when vibrations in the upward and downward directions occur due to unevenness of the road surface and the like, the piston rod 9 is displaced so as to extend and contract from the outer cylinder 4. At this time, a potential difference is generated in each flow path 17 by using the battery 28 according to a command from the controller, and the viscosity of the electrorheological fluid 2 passing through each flow path 17 is controlled to control the generated damping force of the cylinder device 1. Is variably adjusted.

During the extension stroke of the piston rod 9, the check valve 7 on the contraction side of the piston 6 closes due to the movement of the piston 6 in the inner cylinder electrode 3. Before opening the disc valve 8 of the piston 6, the electrorheological fluid 2 in the rod-side oil chamber B is pressurized, and the electrorheological fluid 2 in the rod-side oil chamber B passes through the passage hole 26 of the passage forming member 22. It flows into each flow path 17. At this time, the electrorheological fluid 2 to which the piston 6 has moved flows from the reservoir chamber A into the bottom side oil chamber C by opening the extension side check valve 12 of the bottom valve 10.

On the other hand, during the contraction stroke of the piston rod 9, the contraction side check valve 7 of the piston 6 opens due to the movement of the piston 6 in the inner cylinder electrode 3, and the extension side check valve 12 of the bottom valve 10 closes. Before the bottom valve 10 (disc valve 13) is opened, the electrorheological fluid 2 in the bottom side oil chamber C flows into the rod side oil chamber B. At the same time, the electrorheological fluid 2 corresponding to the amount of the piston rod 9 entering the inner cylinder electrode 3 flows from the rod side oil chamber B into each passage 17 through each passage hole 26 of the passage forming member 22.

Therefore, in either case (during the expansion stroke and the contraction stroke), the electrorheological fluid 2 flowing into each flow path 17 has a potential difference between each flow path 17 (between the intermediate cylinder electrode 15 and the inner cylinder electrode 3). It passes through each flow path 17 toward the outlet side (lower side) with a viscosity corresponding to the potential difference), and flows out from each flow path 17 to the reservoir chamber A through the oil passage 14A of the lower spacer 14. At this time, the cylinder device 1 generates a damping force according to the viscosity of the electrorheological fluid 2 passing through each flow path 17, and can buffer (damp) the vertical vibration of the vehicle.

By the way, in the cylinder device according to the above-mentioned prior art, the electrorheological fluid in the inner cylinder electrode flows into the flow path through the lateral hole formed on the upper end side of the inner cylinder electrode. In this case, the electrorheological fluid collides with the inner peripheral surface of the intermediate cylinder electrode when it flows out from the lateral hole of the inner cylinder electrode, and turns in various directions. As a result, the electrorheological fluid flows into the flow path between the inner cylinder electrode and the intermediate cylinder electrode in a state where the flow is turbulent, so that the pressure loss may increase and the damping force may increase. Further, when air bubbles generated in the flow path are accumulated between the lower end of the upper spacer (insulating member) and the side hole, the hydraulic pressure starts to rise after the air bubbles are crushed at the initial stage of operation of the cylinder device, so that the air pressure is attenuated. There is a risk that the responsiveness of the force will deteriorate and abnormal noise will occur.

Therefore, in the first embodiment, the lateral hole for passing the electrorheological fluid 2 through the inner cylinder electrode 3 is abolished, and the electrorheological fluid is directed from the inside of the inner cylinder electrode 3 (rod side oil chamber B) toward the flow path 17. A closing member 18 (passage forming member 22) is provided to allow the 2 to flow smoothly. The passage forming member 22 includes a radial passage 26A located above the upper end 3B of the inner cylinder electrode 3 and extending outward in the radial direction, and an axis extending axially from the radial passage 26A toward the flow path 17. Four passage holes 26 composed of the directional passage 26B are formed.

As a result, the electrorheological fluid 2 in the oil chamber B on the rod side flows from the radial passage 26A of each passage hole 26 through the axial passage 26B as shown by the arrow F1 shown by the two-dot chain line in FIGS. 1 to 3. It leaks to 17. In this case, the axial passage 26B extends in parallel with the inner cylinder electrode 3 and the intermediate cylinder electrode 15. Therefore, each passage hole 26 of the passage forming member 22 can rectify the electrorheological fluid 2 toward the flow path 17. As a result, the electrorheological fluid 2 can be smoothly flowed from the axial passage 26B toward the flow path 17, so that the pressure loss is reduced and the damping force characteristic of the cylinder device 1 (particularly, the damping force on the soft side). Characteristics) can be stabilized.

Further, on the lower end side (flow path side end portion) of the axial passage 26B, a passage side inclined surface 26B1 that inclines from the radial inner peripheral side toward the radial outer peripheral side is formed. Further, an insulating member-side inclined surface 27A that inclines from the radial inner peripheral side toward the radial outer peripheral side is also formed on the lower end side (flow path side end portion) of the upper spacer 27.

As a result, the air bubbles generated in the flow path 17 move into the rod-side oil chamber B along the insulating member-side inclined surface 27A of the upper spacer 27 and the passage-side inclined surface 26B1 of the passage hole 26, and move to the piston rod 9 and the rod. It is guided into the gas chamber D from between the guide 19 and the gas chamber D. Therefore, it is possible to reduce the generation of air bubble accumulation at the lower end of the upper spacer 27 and the lower end of the passage forming member 22, so that the responsiveness of the damping force can be improved and the generation of abnormal noise can be suppressed. Can be done.

Next, FIGS. 5 and 6 show a second embodiment of the present invention. The feature of this embodiment is that the axial passage of each passage hole is inclined in the same direction as the spiral direction of the flow path (flow path forming member). In the second embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 5, the passage forming member 31 has a lower upper portion as a rod guide inserting portion 32 in which the small diameter portion 19B of the rod guide 19 is press-fitted into the inner peripheral 32A, similarly to the passage forming member 22 according to the first embodiment. The side portion is an inner cylinder electrode insertion portion 33 in which the upper end 3B side of the inner cylinder electrode 3 is press-fitted into the inner circumference 33A. A step portion 34 is formed on the inner circumference 33A of the inner cylinder electrode insertion portion 33 with which the upper end 3B of the inner cylinder electrode 3 abuts. That is, the inner cylinder electrode insertion portion 33 constitutes an annular side portion extending in the axial direction covering the upper end 3B portion (one end portion) of the inner cylinder electrode 3.

A plurality (for example, four) of passage holes 35 are formed so as to be separated in the circumferential direction on the inner peripheral 33A side of the inner cylinder electrode insertion portion 33. Each passage hole 35 communicates with the inside of the inner cylinder electrode 3 (rod side oil chamber B) on the upper end 3B side of the inner cylinder electrode 3 and extends axially toward the flow path 17, and is on the extension side of the piston rod 9. The electrorheological fluid 2 in the inner cylinder electrode 3 is guided to the flow path 17 by the movement and the movement on the contraction side. Each of the passage holes 35 has a radial passage 35A extending radially outward from the inner circumference 33A of the inner cylinder electrode insertion portion 33 at a position corresponding to the step portion 34, and the radial passage 35A toward the flow path 17. It consists of an axial passage 35B extending in the axial direction. Further, at the end of the axial passage 35B on the flow path side, a passage-side inclined surface 35B1 that inclines from the radial inner peripheral side toward the radial outer peripheral side is formed.

Here, the axial passage 35B is inclined in the same direction as the inclination direction of the upper end side 16A (one end side) of the flow path forming member 16 spirally wound around the outer peripheral side of the inner cylinder electrode 3. That is, the axial passage 35B extends in the same direction from the radial passage 35A toward each passage 17. In this case, as shown by the arrow F2 shown by the two-dot chain line in FIG. 6, the electrorheological fluid 2 flows from the axial passage 35B in the same direction as the winding direction of the flow path forming member 16 (clockwise when viewed from above). It flows out toward the road 17.

Therefore, the axial passage 35B of each passage hole 35 can more smoothly guide the electrorheological fluid 2 to each flow path 17 between the flow path forming members 16. As a result, the electrorheological fluid 2 flowing out from the axial passage 35B of each passage hole 35 toward each passage 17 can be further rectified, so that the pressure loss during expansion and contraction of the piston rod 9 can be reduced. At the same time, the generation of bubbles can be reduced. Thus, also in the second embodiment configured as described above, the damping force characteristic of the cylinder device 1 can be stabilized as in the first embodiment described above.

In the first embodiment, the case where each passage hole 26 is formed to have the same width in the circumferential direction has been described as an example. However, the present invention is not limited to this, and as in the first modification shown in FIG. 7, for example, each passage hole 41 is on the downstream side of the width on the upstream side (inlet side) in the flow direction of the electrorheological fluid 2. The width (outlet side) may be widened. On the contrary, the width on the downstream side may be narrower than the width on the upstream side in the flow direction of the electrorheological fluid 2. This also applies to the second embodiment.

In the first embodiment, the case where the closing member 18 is divided and formed by the rod guide 19 and the passage forming member 22 has been described as an example. However, the present invention is not limited to this, and the closing member 51 may be integrally formed by the rod guide portion 51A and the passage forming portion 51B, for example, as in the second modification shown in FIG. This also applies to the second embodiment and the first modification.

In the first embodiment, the case where four passage holes 26 are formed apart from each other in the circumferential direction of the passage forming member 22 will be described as an example. However, the present invention is not limited to this, and for example, 1 to 3 or 5 or more passage holes 26 may be formed. This also applies to the second embodiment and the first and second modifications.

In the first embodiment, the case where four flow path forming members 16 are formed on the outer peripheral side of the inner cylinder electrode 3 apart from each other in the circumferential direction has been described as an example. However, the present invention is not limited to this, and for example, 1 to 3 or 5 or more flow path forming members 16 may be formed. This also applies to the second embodiment and the first and second modifications.

In the first embodiment, the case where the cylinder device 1 has a uniflow structure has been described as an example. However, the present invention is not limited to this, and for example, the cylinder device may have a biflow structure. In the case of the biflow structure, when the advancing / retreating directions of the rods are opposite to each other, each passage hole 26 becomes an outflow portion. This also applies to the second embodiment and the first and second modifications.

In each embodiment, a case where the cylinder device 1 is arranged in the vertical direction has been described as an example. However, the present invention is not limited to this, and the present invention can be arranged in a desired direction according to the mounting target, for example, by tilting the arrangement within a range that does not cause aeration.

In each embodiment, the case where the electrorheological fluid 2 is configured to flow from the upper end side (one end side) to the lower end side (the other end side) in the axial direction has been described as an example. However, the present invention is not limited to this, and depending on the arrangement direction of the cylinder device 1, for example, a configuration in which the flow flows from the lower end side to the upper end side, from the left end side (or the right end side) to the right end side (or the left end side). It is possible to make a configuration that flows from the other end side in the axial direction toward one end side, such as a configuration that flows toward the front end side (or the rear end side) and a configuration that flows from the front end side (or the rear end side) toward the rear end side (or the front end side). can.

In each embodiment, the case where the cylinder device 1 is used for a four-wheeled vehicle has been described as an example. However, the present invention is not limited to this, and for example, a shock absorber used for a two-wheeled vehicle, a shock absorber used for a railroad vehicle, a shock absorber used for various mechanical devices including general industrial equipment, a shock absorber used for a building, and the like. It can be widely used as various cylinder devices (buffers) for buffering objects to be buffered. Furthermore, it is needless to say that the embodiments are exemplary and that partial substitutions or combinations of the configurations shown in 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 embodiment described above, for example, the one described below can be considered.

The first aspect is a cylinder device in which an electroviscosed fluid whose properties change due to an electric field is enclosed and a rod is inserted inside, and an inner cylinder electrode and the inner cylinder electrode which are electrodes having different potentials from each other. An intermediate cylinder electrode provided on the outer periphery of the center, an outer cylinder provided on the outer periphery of the intermediate cylinder electrode, a closing member provided at one end of the inner cylinder electrode, the intermediate cylinder electrode, and the outer cylinder, and the inner cylinder. It has a flow path formed between the electrode and the intermediate cylinder electrode, and the electroviscosed fluid flows by the movement of at least the extension side of the rod from one end side to the other end side in the axial direction. An enlarged diameter portion having an enlarged outer diameter is formed on one end side of the intermediate cylinder electrode on which the closing member is provided. The closing member supports the rod, and one end in the axial direction is the outer diameter. The other end of the cylinder is press-fitted outward so as to cover one end of the inner cylinder electrode, and the annular side portion extending in the axial direction covering one end of the inner cylinder electrode of the closing member is inside the inner cylinder. At one end side of the cylinder electrode, it communicates with the inner cylinder electrode and extends axially toward the flow path, and the electroviscous fluid in the inner cylinder electrode is transferred to the flow path by moving at least the extension side of the rod. One or a plurality of guiding passage holes are formed, and an insulating member is provided between the enlarged diameter portion and the annular side portion.

As a second aspect, in the first aspect, the closing member is provided between the rod guide that supports the rod and is provided on the outer cylinder, and the insulating member and the inner cylinder electrode. Alternatively, the rod guide and the passage forming member are composed of a passage forming member having a plurality of passage holes formed therein, and when a force is applied in the axial direction, the passage forming member with respect to the rod guide. It is made of a metal material with a small amount of deformation.

As a third aspect, in the first or second aspect, a passage side inclined surface inclined from the radial inner peripheral side to the radial outer peripheral side is formed at the flow path side end portion of the passage hole. ing.

As a fourth aspect, in the first, second or third aspect, the insulation member side inclination is inclined from the radial inner peripheral side to the radial outer peripheral side at the flow path side end portion of the insulating member. A surface is formed.

As a fifth aspect, in the first, second, third or fourth aspect, the one or more passage holes communicate with the inner cylinder electrode on one end side of the inner cylinder electrode in the radial direction. It consists of a radial passage extending outward and an axial passage extending axially from the radial passage toward the flow path.

As a sixth aspect, in the fifth aspect, one or more of the flow paths spirally extend from one end side to the other end side in the axial direction between the inner cylinder electrode and the intermediate cylinder electrode. The flow path forming member is provided, and the axial passage is inclined in the same direction as the inclination direction of one end side of the one or more flow path forming members.

1 Cylinder device 2 Electrorheological fluid 3 Inner cylinder electrode 4 Outer cylinder 9 Piston rod (rod)
15 Intermediate cylinder electrode 15B Diameter expansion part 17 Flow path 18, 51 Closure member 19 Rod guide 22, 31 Passage forming member 24 Inner cylinder electrode insertion part 26, 35, 41 Passage hole 26A, 35A Radial passage 26B, 35B Axial passage 26B1,35B1 Passage side inclined surface 27 Upper spacer (insulating member)
27A Insulation member side inclined surface

Claims (6)

A cylinder device in which an electrorheological fluid whose properties change due to an electric field is enclosed and a rod is inserted inside.
An inner cylinder electrode that is an electrode having different potentials, an intermediate cylinder electrode provided on the outer periphery of the inner cylinder electrode, and an intermediate cylinder electrode.
An outer cylinder provided on the outer circumference of the intermediate cylinder electrode and
A closing member provided at one end of the inner cylinder electrode, the intermediate cylinder electrode, and the outer cylinder, and
A flow path formed between the inner cylinder electrode and the intermediate cylinder electrode and through which the electrorheological fluid flows by movement of the rod at least on the extension side from one end side to the other end side in the axial direction.
Have,
An enlarged diameter portion having an enlarged outer diameter is formed on one end side of the intermediate cylinder electrode on which the closing member is provided.
The closing member supports the rod, has one end in the axial direction provided on the outer cylinder, and the other end is press-fitted outward so as to cover one end of the inner cylinder electrode.
The annular side portion of the closing member that covers one end of the inner cylinder electrode communicates with the inner cylinder electrode on the one end side of the inner cylinder electrode and extends axially toward the flow path. , At least the extension side movement of the rod forms one or more passage holes that guide the electrorheological fluid in the inner cylinder electrode to the flow path.
A cylinder device characterized in that an insulating member is provided between the enlarged diameter portion and the annular side portion. The closing member includes a rod guide that supports the rod and is provided on the outer cylinder, and a passage forming member that is provided between the insulating member and the inner cylinder electrode and has one or more passage holes formed therein. Consists of
The rod guide and the passage forming member are characterized in that the passage forming member is made of a metal material having a smaller amount of deformation with respect to the rod guide when a force is applied in the axial direction. The cylinder device according to claim 1. The cylinder according to claim 1 or 2, wherein a passage-side inclined surface that inclines from the radial inner peripheral side to the radial outer peripheral side is formed at the flow path-side end portion of the passage hole. Device. 2. The cylinder device described. The one or more passage holes are a radial passage that communicates with the inner cylinder electrode on one end side of the inner cylinder electrode and extends outward in the radial direction, and a shaft from the radial passage toward the flow path. The cylinder device according to claim 1, 2, 3 or 4, wherein the cylinder device comprises an axial passage extending in a direction. The flow path is provided with one or more flow path forming members spirally extending from one end side to the other end side in the axial direction between the inner cylinder electrode and the intermediate cylinder electrode.
The cylinder device according to claim 5, wherein the axial passage is inclined in the same direction as the inclination direction on one end side of the one or more flow path forming members.

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