JP6869837B2 - 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 cylinder device (vibration damper) using an electrorheological fluid, the properties of the fluid are described by an electric field in the flow path between the inner cylinder (inner tube) and the electrode cylinder (electrode tube). A configuration in which a changing electrorheological fluid flows is disclosed. Further, an outer cylinder (outer tube) is provided on the outside of the electrode cylinder, and a reservoir chamber (ring space) is provided between the electrode cylinder and the outer cylinder. Further, the inside of the inner cylinder is defined by a piston into a rod side chamber on the piston rod side and a bottom side chamber on the bottom side. On this basis, the electrorheological fluid in the reservoir chamber and the electrorheological fluid flowing out of the flow path flow to the bottom concubine via the bottom valve (check valve), respectively.

International Publication No. 2014/135183

By the way, the electrorheological fluid that has become highly viscous through the flow path between the inner cylinder and the electrode cylinder maintains the high viscosity state immediately after flowing out from the flow path into the reservoir chamber. Therefore, according to Patent Document 1, there is a problem that the electrorheological fluid in a high-viscosity state obstructs the flow of the low-viscosity electrorheological fluid flowing toward the bottom side chamber through the reservoir chamber.

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 improve vibration damping performance and responsiveness by smoothing the flow of electrorheological fluid. The purpose is to provide a cylinder device.

The present invention includes an inner cylinder in which an electroviscous fluid whose properties change due to an electric field is sealed, and an outer cylinder provided on the outside of the inner cylinder, one end side in the axial direction is open and the other end side is closed by a bottom cap. A piston that is slidably inserted into the inner cylinder in the axial direction and defined as a rod side chamber located on one side in the axial direction and a bottom side chamber located on the other side in the inner cylinder, and the inner cylinder. A piston rod inserted from one side in the axial direction and connected to the piston in the inner cylinder, and provided between the inner cylinder and the outer cylinder, and one in the axial direction by the expansion and contraction operation of the piston rod. An intermediate electrode cylinder that forms a flow path through which the electroviscous fluid flows from one side to the other side with the inner cylinder, and the electroviscous fluid formed between the intermediate electrode cylinder and the outer cylinder. It has a reservoir chamber in which a working fluid is sealed, a valve body arranged between the inner cylinder, the intermediate electrode cylinder, and the bottom cap, and the electroviscosity between the bottom side chamber and the reservoir chamber. A bottom valve that allows fluid to flow in and out, a bottom valve chamber formed between the valve body of the bottom valve and the bottom cap, and a reservoir chamber and the bottom valve provided in the valve body of the bottom valve. The valve body of the bottom valve is provided with a communication passage that communicates with the chamber, and the electroviscous fluid in the flow path is circulated toward the bottom valve chamber on the other end side of the intermediate electrode cylinder. A fluid passage is provided, and the communication passage and the fluid passage are arranged at different positions in the circumferential direction of the valve body.
Further, in the present invention, an inner cylinder in which an electroviscous fluid whose properties change due to an electric field is sealed, and an outer cylinder provided on the outside of the inner cylinder, one end side in the axial direction is opened and the other end side is closed by a bottom cap. A cylinder, a piston that is slidably inserted into the inner cylinder in the axial direction and defined as a rod side chamber located on one side in the axial direction and a bottom side chamber located on the other side in the inner cylinder, and the above. A piston rod inserted from one side of the inner cylinder in the axial direction and connected to the piston in the inner cylinder is provided between the inner cylinder and the outer cylinder, and is provided in the axial direction by the expansion and contraction operation of the piston rod. An intermediate electrode cylinder that forms a flow path through which the electroviscous fluid flows from one side to the other side is formed between the inner cylinder and the intermediate electrode cylinder and the outer cylinder, and the electricity is formed. It has a reservoir chamber in which a viscous fluid and a working gas are sealed, and a valve body arranged between the inner cylinder, the intermediate electrode cylinder, and the bottom cap, and the valve body is arranged between the bottom side chamber and the reservoir chamber. The bottom valve that allows the electroviscous fluid to flow in and out, the bottom valve chamber formed between the valve body of the bottom valve and the bottom cap, and the reservoir chamber and the reservoir chamber provided in the valve body of the bottom valve. The valve body of the bottom valve is provided with a communication passage that communicates with the bottom valve chamber, and the electroviscous fluid in the flow path is directed toward the bottom valve chamber on the other end side of the intermediate electrode cylinder. A fluid passage for circulation is provided, a bottom valve side holding member is provided on the other end side of the intermediate electrode cylinder and between the bottom valve and the bottom valve, and the bottom valve side holding member corresponds to the flow path. An oil passage is formed, and the oil passage causes the electroviscous fluid flowing in the flow path to flow out to the reservoir chamber.

According to the cylinder device of the present invention, the flow of the electrorheological fluid can be smoothed, and the vibration damping performance and responsiveness can be improved.

It is a vertical sectional view which shows the shock absorber as a cylinder device by 1st Embodiment. It is a vertical cross-sectional view which shows the bottom side of a shock absorber enlarged. It is a cross-sectional view of the bottom side of the shock absorber seen from the direction of arrow III-III in FIG. FIG. 5 is a vertical cross-sectional view of a bottom valve or the like provided with a fluid passage according to the second embodiment as viewed from the same position as in FIG.

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

1 to 3 show a first embodiment of the present invention. In FIG. 1, the shock absorber 1 as a cylinder device is configured as a damping force adjusting type hydraulic shock absorber (semi-active damper) using an electrorheological fluid 2 containing an electrorheological fluid or the like sealed inside. The shock absorber 1 constitutes a suspension device for a vehicle together with, for example, a suspension spring (not shown) made of a coil spring. In the following description, one end side in the axial direction of the shock absorber 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 shock absorber 1 includes an inner cylinder electrode 3, an outer cylinder 4, a bottom cap 5, a piston 6, a piston rod 9, an intermediate electrode cylinder 13, a flow path 17, a bottom valve 18, a communication passage 22, and a fluid passage 23. ing.

The inner cylinder electrode 3 constitutes the innermost cylinder (inner cylinder), and is formed in a cylindrical shape extending in the axial direction. An electrorheological fluid 2 which is a functional fluid is sealed inside the inner cylinder electrode 3. Further, a piston rod 9 is inserted into the inner cylinder electrode 3 from one end side in the axial direction. On the outside of the inner cylinder electrode 3, the outer cylinder 4 and the intermediate electrode cylinder 13 are provided so as to be coaxial. A piston rod 9 is inserted inside the inner cylinder electrode 3 so as to be expandable and contractible in the axial direction.

The lower end side of the inner cylinder electrode 3 is fitted and attached to the valve body 19 of the bottom valve 18, 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 so as to penetrate in the radial direction at intervals in the circumferential direction. Further, a partition wall 16 described later is spirally wound and provided on the outer peripheral surface 3B forming the outer peripheral side of the inner cylinder electrode 3.

Here, the inner cylinder electrode 3 is formed of a material serving as a conductor (electric conductor), and is configured as a negative (minus) electrode. The inner cylinder electrode 3 is electrically connected to the negative electrode (minus electrode) of the high voltage driver 24 described later via an outer cylinder 4, a rod guide 10, a bottom valve 18 and the like described later.

The outer cylinder 4 forms the outer shell of the shock absorber 1, and is formed as a cylinder by a material serving as a conductor (electric conductor). The outer cylinder 4 is provided outside the inner cylinder electrode 3 and the intermediate electrode cylinder 13, and forms a reservoir chamber A communicating with each flow path 17 between the outer cylinder 4 and the intermediate electrode cylinder 13. In this case, the lower end side of the outer cylinder 4 is a closed end because the bottom cap 5 is fixed to the lower end of the outer cylinder 4 by using a welding means or the like. The bottom cap 5 is formed so as to project downward toward the center in the radial direction.

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 fixes the inner cylinder electrode 3, the rod guide 10, and the intermediate electrode cylinder 13 together with the seal member 12 in the outer cylinder 4 by pressing the outer peripheral side of the seal member 12 from above.

Here, the inner cylinder electrode 3 and the outer cylinder 4 form a cylinder, and an electrorheological fluid 2 (ERF) is sealed 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, 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) that are mixed (dispersed) in the base oil and whose viscosity changes according to a change in an electric field. ing.

As will be described later, the shock absorber 1 generates a potential difference in the flow path 17 between the inner cylinder electrode 3 and the intermediate electrode cylinder 13 to control the viscosity of the electrorheological fluid 2 passing through the flow path 17. , It is configured to control (adjust) the generated damping force.

An annular reservoir chamber A is formed between the outer cylinder 4 and the intermediate electrode cylinder 13. The reservoir chamber A is filled with a gas that becomes a working gas together with the electrorheological fluid 2. The 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 during the contraction stroke of the piston rod 9.

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 chamber B located on the upper side and a bottom side chamber C located on the lower side. A plurality of oil passages 6A and 6B that allow the rod side chamber B and the bottom side 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 (only one of each is shown).

Here, the shock absorber 1 according to the embodiment has a uniflow structure. Therefore, the electrorheological fluid 2 in the inner cylinder electrode 3 is directed from the rod side chamber B to the flow path 17 through the oil holes 3A of the inner cylinder electrode 3 in both the contraction stroke and the extension stroke of the piston rod 9. It always circulates in one direction (the direction indicated by the arrow F 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 of the piston rod 9, and other than this. A check valve 7 on the reduction side is provided to close the valve at the time of. The reduction side check valve 7 allows the electrorheological fluid 2 in the bottom side chamber C to flow in each oil passage 6A toward the rod side chamber B, and allows the electrorheological fluid 2 to flow in the opposite direction. Stop. That is, the reduction side check valve 7 allows only the flow of the electrorheological fluid 2 from the bottom side chamber C to the rod side chamber B.

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

The piston rod 9 extends in the inner cylinder electrode 3 in the axial direction (vertical direction in FIG. 1). The lower end side of the piston rod 9 is connected (fixed) to the piston 6 in the inner cylinder electrode 3 by using a nut 9A or the like. On the other hand, the upper end side of the piston rod 9 extends to the outside of the inner cylinder electrode 3 and the outer cylinder 4 in a state of being guided by the rod guide 10 through the rod side chamber B.

The rod guide 10 is provided so as to be fitted to the upper end side of the inner cylinder electrode 3 and the outer cylinder 4. The rod guide 10 closes the inner cylinder electrode 3 and the upper end side of the outer cylinder 4. The rod guide 10 supports the piston rod 9 via the guide bush 11, and is formed as a stepped tubular body made of a metal material (conductor). In this case, the rod guide 10 may be formed by using a material made of an insulator, a dielectric, a high resistor or the like, for example, a hard resin material, when the valve body 19 described later is a metal material (conductor). It is possible. Then, the rod guide 10 positions the upper portion of the inner cylinder electrode 3 and the upper portion of the intermediate electrode cylinder 13 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 sealing member 12 is provided between the rod guide 10 and the crimped portion 4A of the outer cylinder 4. The seal member 12 has a liquid-tight and airtight seal between the outer cylinder 4 and the piston rod 9 by the sealing portion on the inner peripheral side sliding contact with the outer peripheral surface of the piston rod 9.

The intermediate electrode cylinder 13 is provided on the outside of the inner cylinder electrode 3 so as to surround the inner cylinder electrode 3. The intermediate electrode cylinder 13 is formed so as to extend in the axial direction at an intermediate position between the inner cylinder electrode 3 and the outer cylinder 4. The intermediate electrode cylinder 13 is made of a material (for example, a metal material) that serves as a conductor, and constitutes a cylindrical positive electrode. The intermediate electrode cylinder 13 forms a flow path 17 described later that communicates with the rod side chamber B and the reservoir chamber A between the inner cylinder electrode 3 and the rod side chamber B. The intermediate electrode cylinder 13 is electrically connected to the positive electrode (positive electrode) of the high voltage driver 24 described later.

The upper end side of the intermediate electrode cylinder 13 is held in a vertically and radial direction with respect to the rod guide 10 via the upper holding member 14. On the other hand, the lower end side of the intermediate electrode cylinder 13 is held in a vertically and radially positioned state with respect to the valve body 19 of the bottom valve 18 via the lower holding member 15 as the bottom valve side holding member. A plurality of oil passages 15A are formed in the lower holding member 15 so as to correspond to the respective flow paths 17 described later. The oil passage 15A allows the electrorheological fluid 2 flowing through the flow path 17 to flow out to the reservoir chamber A, and forms a part of the flow path 17.

A plurality of partition walls 16 are spirally extended in the vertical direction on the outer peripheral surface of the inner cylinder electrode 3. Each partition wall 16 is formed as a ridge protruding outward in the radial direction 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 intermediate electrode cylinder 13. As a result, each partition wall 16 forms a plurality of flow paths 17 between the inner cylinder electrode 3 and the intermediate electrode cylinder 13. Each partition wall 16 is formed of a polymer material having elasticity such as elastomer and having electrical insulating property, for example, synthetic rubber. Each partition wall 16 is fixed (adhered) to the inner cylinder electrode 3 using, for example, an adhesive.

Each flow path 17 is spirally divided by each partition wall 16, so that a plurality of, for example, four are formed between the inner cylinder electrode 3 and the intermediate electrode cylinder 13. In each flow path 17, the electrorheological fluid 2 flows 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 expansion and contraction operation of the piston rod 9. In each flow path 17, the upper side, which is the upstream side in the flow direction of the electrorheological fluid 2, is always in communication with the rod side chamber B by the oil hole 3A of the inner cylinder electrode 3. That is, as shown in the flow direction of the electrorheological fluid 2 indicated by the arrow F in FIG. 1, the shock absorber 1 is provided in each flow path 17 from the rod side chamber B through the oil hole 3A in both the reduction stroke and the extension stroke of the piston 6. The electrorheological fluid 2 is allowed to flow into the water. The electrorheological fluid 2 that has flowed into each flow path 17 flows from the upper end side to the lower end side in both the extension operation and the reduction operation of the piston rod 9.

Here, in each flow path 17, a flow resistance is imparted to the electrorheological fluid 2 that flows. For this purpose, the intermediate electrode cylinder 13 is connected to a battery (not shown) as a power source via, for example, a high voltage driver 24 that generates a high voltage. The high voltage driver 24 serves as a voltage supply unit (electric field supply unit), and serves as an electrode (electrode) that applies an electric field (voltage) to the electrorheological fluid 2 in the intermediate electrode cylinder 13 and each flow path 17. In this case, both ends of the intermediate electrode cylinder 13 are electrically insulated by the electrically insulating holding members 14 and 15. On the other hand, the inner cylinder electrode 3 is connected to the negative electrode (ground) of the high voltage driver 24 via the rod guide 10, the bottom valve 18, the bottom cap 5, the outer cylinder 4, and the like.

In each flow path 17, an electric field (voltage) is applied to the electrorheological fluid 2 by the high voltage driver 24 to increase the viscosity of the electrorheological fluid 2 and increase the flow resistance. Then, the electrorheological fluid 2 flowing through each flow path 17 flows out from the oil passage 15A of the lower holding member 15 to the reservoir chamber A. At this time, even if the electrorheological fluid 2 that has reached a high viscosity state (high viscosity state) passes through each flow path 17 flows out to the reservoir chamber A, the electrorheological fluid 2 maintains the high viscosity state immediately after flowing out. ..

Next, the configuration of the bottom valve 18 provided on the lower end side of the shock absorber 1 will be described. The bottom valve 18 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 18 allows the electrorheological fluid 2 to flow in and out between the bottom side chamber C and the reservoir chamber A. For this purpose, the bottom valve 18 includes a valve body 19, an extension side check valve 20, and a reduction side disc valve 21.

The valve body 19 is arranged between the inner cylinder electrode 3 and the intermediate electrode cylinder 13 and the bottom cap 5, and partitions the reservoir chamber A and the bottom side chamber C. As shown in FIG. 2, the valve body 19 is formed as a short, covered stepped cylinder that is fitted and fixed between the upper surface side of the bottom cap 5 and the lower end side of the inner cylinder electrode 3. .. That is, the valve body 19 is formed by a tubular portion 19A supported between the bottom cap 5, the inner cylinder electrode 3 and the lower holding member 15, and a thick lid portion 19B that closes the upper side of the tubular portion 19A. It is formed. The valve body 19 is formed by using a metal material (conductor). On the other hand, when the rod guide 10 described above is a metal material (conductor), the valve body 19 may be formed by using a material made of an insulator, a dielectric, a high resistor or the like, for example, a hard resin material. It is possible.

Here, a bottom valve chamber D is formed between the valve body 19 and the bottom cap 5. The bottom valve chamber D constitutes a part of the reservoir chamber A by constantly communicating with the reservoir chamber A via the communication passage 22 described later.

The tubular portion 19A of the valve body 19 has an inner peripheral surface 19A1 located on the bottom valve chamber D side and an outer peripheral surface 19A2 located on the reservoir chamber A side. Further, the tubular portion 19A is provided with a communication passage 22 so as to penetrate in the radial direction.

On the other hand, the lid portion 19B is provided with oil passages 19C and 19D penetrating in the vertical direction over the upper surface 19B1 and the lower surface 19B2. The oil passages 19C and 19D allow the reservoir chamber A (bottom valve chamber D) and the bottom side chamber C to communicate with each other, and a plurality of oil passages 19C and 19D, for example, five are formed at intervals in the circumferential direction. The number and diameter of the oil passages 19C and 19D are designed according to the flow rate of the electrorheological fluid 2 flowing between the reservoir chamber A and the bottom side chamber C, and are not limited to five, but the shape thereof. May be formed into, for example, a long hole other than the round hole.

Further, an annular step portion 19E is formed at a boundary position between the upper portion of the tubular portion 19A, specifically, the upper portion of the tubular portion 19A and the outer peripheral portion of the lid portion 19B. The step portion 19E is formed by a peripheral surface portion 19E1 that abuts on the inner cylinder electrode 3 from the inner diameter side and a flat surface portion 19E2 that abuts on the inner cylinder electrode 3 and the lower holding member 15 from the lower side. The lower end of the inner cylinder electrode 3 and the lower end of the lower holding member 15 are fitted and attached to the step portion 19E.

The extension-side check valve 20 is provided, for example, on the upper surface 19B1 side of the lid portion 19B of the valve body 19. The extension-side check valve 20 opens when the piston 6 slides and displaces upward during the extension stroke of the piston rod 9, and closes at other times. The extension side check valve 20 allows the electrorheological fluid 2 in the bottom valve chamber D to flow in each oil passage 19C toward the bottom side chamber C, and the electrorheological fluid 2 flows in the opposite direction. To prevent. That is, the extension side check valve 20 allows only the flow of the electrorheological fluid 2 from the reservoir chamber A side to the bottom side chamber C side.

The disc valve 21 on the reduction side is provided, for example, on the lower surface 19B2 side of the lid portion 19B. The disc valve 21 on the reduction side opens when the pressure in the bottom side chamber C 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 reduced. Relieve to the reservoir chamber A (bottom valve chamber D) side via each oil passage 19D.

The communication passage 22 is provided in the tubular portion 19A constituting the valve body 19 of the bottom valve 18. The communication passage 22 communicates the reservoir chamber A and the bottom valve chamber D, and is formed as a groove portion that penetrates the tubular portion 19A in the radial direction over the inner peripheral surface 19A1 and the outer peripheral surface 19A2 of the tubular portion 19A. There is. Further, as shown in FIG. 3, a plurality of, for example, five communication passages 22 are provided at intervals in the circumferential direction. The number and size (flow path area) of each communication passage 22 are designed according to the flow rate of the electrorheological fluid 2 flowing between the reservoir chamber A and the bottom valve chamber D, and are not limited to five. However, the shape may be another shape such as a round hole.

Next, the shape and function of the fluid passage 23 according to the first embodiment provided in the valve body 19 of the bottom valve 18 will be described.

The fluid passage 23 is provided on the outer peripheral side of the valve body 19 constituting the bottom valve 18. The fluid passage 23 circulates the electrorheological fluid 2 in each flow path 17 toward the bottom valve chamber D on the lower end side of the intermediate electrode cylinder 13. In the fluid passage 23 according to the first embodiment, one end 23A communicates with the oil passage 15A of the lower holding member 15 forming the outflow side of the flow path 17, and the other end 23B communicates with the bottom valve chamber D.

More specifically, one end 23A of the fluid passage 23 is a corner portion between the outer peripheral surface 19A2 of the tubular portion 19A of the valve body 19 and the flat portion 19E2 of the stepped portion 19E at a position communicating with the oil passage 15A of the lower holding member 15. It is open at the position. One end 23A of the fluid passage 23 opened at this position directly communicates with both the oil passage 15A (flow passage 17) of the lower holding member 15 and the reservoir chamber A. Therefore, at one end 23A of the fluid passage 23, the electrorheological fluid 2 before flowing out from the oil passage 15A of the lower holding member 15 to the reservoir chamber A and the electrorheological fluid 2 after flowing out from the oil passage 15A into the reservoir chamber A 2 and can flow in.

The other end 23B of the fluid passage 23 directly communicates with the bottom valve chamber D.

Here, a plurality of, for example, five fluid passages 23 are provided at intervals in the circumferential direction of the valve body 19. In this case, as shown in FIG. 3, the five communication passages 22 and the five fluid passages 23 are arranged at different positions in the circumferential direction of the valve body 19. As a result, the highly viscous electrorheological fluid 2 flowing out from each oil passage 15A of the lower holding member 15 flows from the reservoir chamber A to the bottom valve chamber D via the communication passage 22 during the extension stroke of the piston rod 9. It is possible to prevent the electrorheological fluid 2 in a viscous state from interfering with the electrorheological fluid 2. Further, each fluid passage 23 is arranged at a position different from that of the oil passage 19C on the extension side. This makes it possible to prevent the highly viscous electrorheological fluid 2 flowing out of the fluid passage 23 from flowing into the oil passage 19C.

The number and size (flow path area) of each fluid passage 23 are designed according to, for example, the flow rate of the electrorheological fluid 2 flowing out from each flow path 17 (each oil passage 15A of the lower holding member 15). The number is not limited to five, and the shape may be a shape other than the round hole.

Each fluid passage 23 configured in this way has a low viscosity state in which the electrorheological fluid 2 maintaining the high viscosity state immediately after passing through each flow path 17 flows from the reservoir chamber A toward the communication passage 22. It can be circulated to the bottom valve chamber D via the communication passage 22 while preventing interference with the electrorheological fluid 2.

The high voltage driver 24 increases the viscosity of the electrorheological fluid 2 by applying an electric field (voltage) to the electrorheological fluid 2 flowing through each flow path 17. The high voltage driver 24 generates a high voltage and is connected to a battery (not shown) as a power source. The high voltage driver 24 serves as a voltage supply unit (electric field supply unit), and the intermediate electrode cylinder 13 serves as an electrode (electrode) that applies an electric field (voltage) to the electrorheological fluid 2 in each flow path 17. In this case, both ends of the intermediate electrode cylinder 13 are electrically insulated by the electrically insulating holding members 14 and 15. On the other hand, the inner cylinder electrode 3 is connected to the negative electrode (ground) of the high voltage driver 24 via the rod guide 10, the bottom valve 18, the bottom cap 5, the outer cylinder 4, and the like.

The shock absorber 1 according to the first embodiment has the above-described configuration, and its operation 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 traveling, if vibration in the vertical direction is generated due to unevenness of the road surface or the like, the piston rod 9 is displaced so as to extend or contract from the outer cylinder 4. At this time, a potential difference is generated in each flow path 17 by using a high voltage driver 24 according to a command from a controller (not shown), and the viscosity of the electrorheological fluid 2 passing through each flow path 17 is controlled. , The generated damping force of the shock absorber 1 is variably adjusted.

During the extension stroke of the piston rod 9, the check valve 7 on the reduction side of the piston 6 is closed by 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 chamber B is pressurized and flows into each flow path 17 through each oil hole 3A of the inner cylinder electrode 3. At this time, the electrorheological fluid 2 due to the movement of the piston 6 opens the extension side check valve 20 of the bottom valve 18 from the reservoir chamber A (bottom valve chamber D) and flows into the bottom side chamber C.

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 20 of the bottom valve 18 is closed. Before the bottom valve 18 (disc valve 21) is opened, the electrorheological fluid 2 in the bottom side chamber C flows into the rod side 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 into each flow path 17 from the rod side chamber B through the oil holes 3A of the inner cylinder electrode 3.

Therefore, in both the extension stroke and the contraction stroke, the electrorheological fluid 2 flowing into each flow path 17 has a potential difference between each flow path 17 (potential difference between the inner cylinder electrode 3 and the intermediate electrode cylinder 13). ), It passes through each flow path 17 toward the outlet side (lower side), and flows out from each flow path 17 to the reservoir chamber A through the oil passage 15A of the lower holding member 15. At this time, the shock absorber 1 can generate 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.

Here, the electrorheological fluid 2 that has become highly viscous through each flow path 17 between the inner cylinder electrode 3 and the intermediate electrode cylinder 13 is high immediately after flowing out from each flow path 17 to the reservoir chamber A. Maintains a viscous state. Therefore, during the extension stroke of the piston rod 9, the highly viscous electrorheological fluid 2 may obstruct the flow of the low-viscosity electrorheological fluid 2 flowing from the reservoir chamber A toward the bottom valve chamber D.

However, in the first embodiment, the valve body 19 of the bottom valve 18 is provided with the electrorheological fluid 2 in the flow path 17 in the oil passage 15A of the lower holding member 15 on the other end side of the intermediate electrode cylinder 13. A fluid passage 23 is provided to circulate toward the bottom valve chamber D.

Therefore, the fluid passage 23 is a flow of the electrorheological fluid 2 in the low viscosity state in which the electrorheological fluid 2 maintaining the high viscosity state immediately after passing through the flow path 17 flows from the reservoir chamber A toward the communication passage 22. It can be distributed to the bottom valve chamber D in a different flow from the above. As a result, in the extension stroke of the piston rod 9, the flow of the electrorheological fluid 2 from the reservoir chamber A to the bottom side chamber C can be smoothed and a sufficient flow rate can be secured, so that the vibration damping performance and the responsiveness can be improved. it can.

Further, the plurality of communication passages 22 and the plurality of fluid passages 23 are arranged at different positions in the circumferential direction of the valve body 19. As a result, the highly viscous electrorheological fluid 2 flowing out from each oil passage 15A of the lower holding member 15 flows from the reservoir chamber A to the bottom valve chamber D via the communication passage 22, and the electrorheological fluid 2 in a low viscosity state flows. The electrorheological fluid 2 can be smoothly circulated from the reservoir chamber A to the bottom side chamber C.

A lower holding member 15 as a bottom valve side holding member is provided between the lower end side of the intermediate electrode cylinder 13 and the bottom valve 18. An oil passage 15A corresponding to the flow path 17 is formed in the lower holding member 15, and the oil passage 15A can allow the electrorheological fluid 2 flowing through the flow path 17 to flow out to the reservoir chamber A.

Next, FIG. 4 shows a second embodiment of the present invention. 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. 4, the lower holding member 115 as the bottom valve side holding member according to the second embodiment is provided on the lower end side of the intermediate electrode cylinder 13 and between the bottom valve 18 and the lower holding member 115. An oil passage 115A corresponding to the flow path 17 is formed in the lower holding member 115. The oil passage 115A extends upward and downward along the inner cylinder electrode 3 and penetrates therethrough. As a result, the lower holding member 115 can directly flow the electrorheological fluid 2 flowing through the flow path 17 into the fluid passage 31 described later.

A plurality of fluid passages 31 according to the second embodiment are provided on the outer peripheral side of the valve body 19 of the bottom valve 18 in substantially the same manner as the fluid passages 23 according to the first embodiment, and each of them is provided during the extension stroke of the piston rod 9. The electrorheological fluid 2 in the flow path 17 is circulated toward the bottom valve chamber D via the flow path 115A of the lower holding member 115.

However, the fluid passage 31 according to the second embodiment has a point that one end 31A of the fluid passage 31 is directly communicated with the oil passage 115A of the lower holding member 115 by opening only the flat portion 19E2 of the step portion 19E. It is different from the fluid passage 23 according to the first embodiment. On the other hand, the other end 31B of the fluid passage 31 is open to the inner peripheral surface 19A1 of the tubular portion 19A of the valve body 19. As a result, the electrorheological fluid 2 that maintains the high viscosity state can be directly circulated from each oil passage 115A of the lower holding member 115 to the bottom valve chamber D. Each fluid passage 31 configured in this way has a low viscosity state in which the electrorheological fluid 2 maintaining the high viscosity state immediately after passing through each flow path 17 flows from the reservoir chamber A toward the communication passage 22. It can be circulated to the bottom valve chamber D while preventing interference with the electrorheological fluid 2.

Thus, even in the second embodiment configured as described above, it is possible to obtain an action effect substantially similar to the action effect according to the first embodiment described above.

In each embodiment, a case where the shock absorber 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 attachment target, for example, by inclining the arrangement within a range that does not cause aeration.

Further, 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 shock absorber 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). A configuration in which the flow flows from the other end side in the axial direction toward one end side, such as a configuration in which the flow flows toward the front end side (or the rear end side) to the rear end side (or the front end side), etc. it can.

Further, in each embodiment, a 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 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 shock absorbers (cylinder devices) for buffering an object to be powered. Furthermore, it goes without saying that the embodiments are exemplary and the configurations shown in the different embodiments can be partially replaced or combined. 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.

In the first aspect, an inner cylinder in which an electroviscous fluid whose properties change due to an electric field is sealed, and an inner cylinder provided on the outside of the inner cylinder, one end side in the axial direction is opened and the other end side is closed by a bottom cap. An outer cylinder, a piston that is slidably inserted into the inner cylinder in the axial direction and defined as a rod side chamber located on one side in the axial direction and a bottom side chamber located on the other side in the inner cylinder. A piston rod inserted from one side in the axial direction of the inner cylinder and connected to the piston in the inner cylinder is provided between the inner cylinder and the outer cylinder, and the shaft is expanded and contracted by the expansion and contraction operation of the piston rod. An intermediate electrode cylinder that forms a flow path through which the electroviscous fluid flows from one side in the direction to the other side is formed between the inner cylinder and the intermediate electrode cylinder and the outer cylinder. It has a reservoir chamber in which an electroviscous fluid and a working gas are sealed, and a valve body arranged between the inner cylinder, the intermediate electrode cylinder, and the bottom cap, and is located between the bottom side chamber and the reservoir chamber. A bottom valve that allows the electroviscous fluid to flow in and out, a bottom valve chamber formed between the valve body of the bottom valve and the bottom cap, and a reservoir chamber provided in the valve body of the bottom valve. The valve body of the bottom valve is provided with a communication passage that communicates with the bottom valve chamber, and the electroviscous fluid in the flow path is directed toward the bottom valve chamber on the other end side of the intermediate electrode cylinder. It is characterized by being provided with a fluid passage for circulation.

As a second aspect, in the first aspect, the communication passage and the fluid passage are arranged at different positions in the circumferential direction of the valve body.

As a third aspect, in the first or second aspect, a bottom valve side holding member is provided on one end side of the intermediate electrode cylinder and between the bottom valve and the bottom valve side holding member. Is characterized in that an oil passage corresponding to the flow path is formed, and the electrorheological fluid flowing through the flow path flows out to the reservoir chamber.

As a fourth aspect, in the first or second aspect, a bottom valve side holding member is provided on one end side of the intermediate electrode cylinder and between the bottom valve and the bottom valve side holding member. Is characterized in that an oil passage corresponding to the flow path is formed, and the electrorheological fluid flowing through the flow path is directly discharged to the fluid passage.

1 Shock absorber (cylinder device)
2 Electrorheological fluid 3 Inner cylinder electrode (inner cylinder)
4 Outer cylinder 5 Bottom cap 6 Piston 9 Piston rod 13 Intermediate electrode cylinder 15,115 Lower holding member (bottom valve side holding member)
15A, 115A oil passage (flow path)
17 Flow path 18 Bottom valve 19 Valve body 22 Continuous passage 23,31 Fluid passage A Reservoir chamber B Rod side chamber C Bottom side chamber D Bottom valve chamber

Claims (3)

An inner cylinder filled with an electrorheological fluid whose properties change with an electric field,
An outer cylinder provided on the outside of the inner cylinder, one end side in the axial direction is open and the other end side is closed by a bottom cap.
A piston that is slidably inserted into the inner cylinder in the axial direction and defined as a rod side chamber located on one side in the axial direction and a bottom side chamber located on the other side in the inner cylinder.
A piston rod inserted from one side of the inner cylinder in the axial direction and connected to the piston in the inner cylinder.
A flow path provided between the inner cylinder and the outer cylinder and through which the electrorheological fluid flows from one side in the axial direction to the other side by the expansion and contraction operation of the piston rod is formed between the inner cylinder and the inner cylinder. Intermediate electrode cylinder and
A reservoir chamber formed between the intermediate electrode cylinder and the outer cylinder and filled with the electrorheological fluid and the working gas.
A bottom valve having a valve body arranged between the inner cylinder, the intermediate electrode cylinder, and the bottom cap, and allowing the electrorheological fluid to flow in and out between the bottom side chamber and the reservoir chamber.
A bottom valve chamber formed between the valve body of the bottom valve and the bottom cap,
A communication passage provided in the valve body of the bottom valve and communicating the reservoir chamber and the bottom valve chamber,
With
The valve body of the bottom valve is provided with a fluid passage on the other end side of the intermediate electrode cylinder to allow the electrorheological fluid in the flow path to flow toward the bottom valve chamber .
A cylinder device characterized in that the communication passage and the fluid passage are arranged at different positions in the circumferential direction of the valve body. An inner cylinder filled with an electrorheological fluid whose properties change with an electric field,
An outer cylinder provided on the outside of the inner cylinder, one end side in the axial direction is open and the other end side is closed by a bottom cap.
A piston that is slidably inserted into the inner cylinder in the axial direction and defined as a rod side chamber located on one side in the axial direction and a bottom side chamber located on the other side in the inner cylinder.
A piston rod inserted from one side of the inner cylinder in the axial direction and connected to the piston in the inner cylinder.
A flow path provided between the inner cylinder and the outer cylinder and through which the electrorheological fluid flows from one side in the axial direction to the other side by the expansion and contraction operation of the piston rod is formed between the inner cylinder and the inner cylinder. Intermediate electrode cylinder and
A reservoir chamber formed between the intermediate electrode cylinder and the outer cylinder and filled with the electrorheological fluid and the working gas.
A bottom valve having a valve body arranged between the inner cylinder, the intermediate electrode cylinder, and the bottom cap, and allowing the electrorheological fluid to flow in and out between the bottom side chamber and the reservoir chamber.
A bottom valve chamber formed between the valve body of the bottom valve and the bottom cap,
A communication passage provided in the valve body of the bottom valve and communicating the reservoir chamber and the bottom valve chamber,
With
The valve body of the bottom valve is provided with a fluid passage on the other end side of the intermediate electrode cylinder to allow the electrorheological fluid in the flow path to flow toward the bottom valve chamber.
A bottom valve side holding member is provided on the other end side of the intermediate electrode cylinder and between the bottom valve and the bottom valve, and an oil passage corresponding to the flow path is formed in the bottom valve side holding member, and the oil is formed. road features and to Resid cylinder device that is flowing out of the electro-rheological fluid has flowed through the flow channel to the reservoir chamber. A bottom valve side holding member is provided on the other end side of the intermediate electrode cylinder and between the bottom valve and the bottom valve, and an oil passage corresponding to the flow path is formed in the bottom valve side holding member, and the oil is formed. road cylinder device according to claim 1, characterized in that to flow out directly the electrorheological fluid has flowed through the flow channel to the fluid passageway.

Images