JP5483559B2 - Magnetorheological fluid flow type damper - Google Patents

Description

  In the present invention, by moving the piston relatively in the cylinder filled with the magnetorheological fluid, the magnetorheological fluid is circulated between the hydraulic chambers partitioned by the piston, and the flow resistance of the magnetorheological fluid is increased by the magnetic field on the flow path. The present invention relates to a magnetorheological fluid flow type damper that suppresses expansion and contraction of a piston rod and a cylinder.

  Conventionally, the inside of a cylinder is partitioned into first and second pressure chambers in the axial direction by a piston, the piston rod is fixed to the piston, is inserted into the cylinder so that it can freely enter and exit, and the cylinder is filled with a magnetorheological fluid. (See Patent Document 1). A bypass pipe is communicated between the two hydraulic chambers of the cylinder outside the cylinder, and a magnetic field is applied to the magnetorheological fluid flowing therethrough by an electromagnet.

JP 2001-165229 A

In general, hydraulic fluid is sealed with a sealant of packing or O-ring at the sliding part of hydraulic equipment. The sealing performance of the hydraulic oil is maintained by a contact pressure distribution in which a peak pressure higher than the internal pressure is generated in the packing due to a repulsive force in a compressed state in the O-ring. These sealing materials need to improve lubrication characteristics and reduce wear on the sliding surface in order to maintain sealing performance while frictionally contacting the sliding portion. As this means, for example, grease is applied to the sliding portion of the O-ring, and an appropriate amount of lubricating oil film is formed on the sliding surface of the packing.
However, in the damper using the conventional magnetorheological fluid, since the magnetorheological fluid contains magnetic powder, if a packing or an O-ring is used for the sliding part between the piston rod and the member supporting the piston rod , a lubricating oil film is formed. For this reason, the fluid is drawn into the sliding part, and the magnetic powder contained in the fluid adheres to roughen the surface of the sliding part, so the wear of the packing and O-ring becomes severe and the sealing performance is impaired. Lead to hydraulic fluid leakage. Even if the magnetic powder is prevented from entering the sliding portion, depending on the sliding state, the lubricating oil film may not be formed, and the packing and the O-ring may be heavily worn.
Accordingly, the present invention is, instead of the configuration of interposing a packing and O-ring as a sealing material in the sliding portion, a gap is provided between the members so as not to slide contact, the Rukoto there is interposed a rubber membrane, sliding An object of the present invention is to provide a magnetorheological fluid flow type damper capable of preventing wear due to movement and exhibiting desired performance over a long period of time.

In order to solve the above-mentioned problems, a magnetorheological fluid flow type damper of the present invention is connected to one of a support or a supported body and has a cylinder 1 filled with a magnetorheological fluid therein, The piston 3 is divided into the first and second hydraulic chambers 9 and 10, and the piston 3 is movable in the axial direction in the cylinder 1. The piston 3 is fixed to the piston 3 and is inserted into the cylinder 1 so as to freely enter and exit. The flow resistance of the magnetorheological fluid is changed along the flow path 25 of the magnetorheological fluid flowing between the piston rod 2 connected to the other side and the first hydraulic chamber 9 and the second hydraulic chamber 10 of the cylinder 1. And an electromagnet 26 that forms a magnetic field for generating the magnetic field. A seal unit 4 having an insertion hole for supporting the piston rod 2 through the piston rod 2 so as to be movable in the axial direction is airtightly fixed to the outside of the insertion side cover 1b of the piston rod 2 in the cylinder 1. An annular gap is formed between the insertion hole of the seal unit and the piston rod. The elastic thin film body 21 is airtightly fixed to the inner peripheral portion of the insertion hole at the outer peripheral edge portion, and is airtightly fixed to the outer peripheral portion of the piston rod at the inner peripheral edge portion. The intermediate portion of the elastic thin film body 21 is folded and held in a gap so as to be extendable, thereby avoiding contact between the insertion hole and the piston rod via the magnetorheological fluid, and from the hydraulic chamber of the cylinder to the outside. Leakage of magnetorheological fluid to the

In the present invention, the elastic thin film 21 is interposed in the gap between the relative moving portions of the seal unit 4 and the piston rod 2 to prevent the flow of the magnetorheological fluid from the cylinder 1 to the outside. Prevents fluid from leaking outside. Since there is no sliding contact with a magnetorheological fluid interposed between the relative moving parts of the seal unit 4 and the piston rod 2, it is possible to prevent the wear of the members and maintain the sealing performance over a long period of time. Can be maintained for a long period of time to extend the service life.

It is a longitudinal section of a magnetorheological fluid flow type damper concerning the present invention. It is an expanded sectional view of a sliding part.

An embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, the damper according to the present embodiment includes a cylindrical cylinder 1, a piston rod 2 inserted into the cylinder 1 so as to freely enter and exit in the axial direction, a piston 3 fixed to one end of the piston rod 2, The seal unit 4 provided at the insertion side end of the piston rod 2 in the cylinder 1, the bypass pipe 5 provided at the side of the cylinder 1, and the bypass pipe 5 provided at the side of the cylinder 1 And an accumulator 6. The cylinder 1, the bypass pipe 5, and the accumulator 6 are integrally fixed to the frame board 33. The frame board 33 is provided with mounting holes into which one end portions of the cylinder 1, the bypass pipe 5 and the accumulator 6 can be fitted. Inside the coupling board 32, there is a communication path 34 for communicating the cylinder 1, the bypass pipe 5 and the accumulator 6.

  The cylinder 1 is connected by a support member 7 via a frame board 33 to one of a support body such as a structure or a machine frame (not shown) or a support body to be supported by a damper. The inside of the cylinder 1 is divided into two hydraulic chambers 9 and 10 in the axial direction front and rear by a piston 3 that is slidably and airtightly fitted. These hydraulic chambers 9 and 10 are filled with a magnetorheological fluid obtained by mixing magnetic powder in a medium such as oil. The magnetorheological fluid has a characteristic that the viscosity increases in response to a magnetic field and the flow resistance increases. One end lid 1 a of the cylinder 1 is provided with a communication hole 11 communicating with the communication path 34 of the coupling board 32, and an oil absorption valve 12 is provided in the inner opening of the communication hole 11. The oil absorbing valve 12 is pressed against the end lid 1a so as to close the communication hole 11 by a compressed spring 13 interposed between the locking ring 14 fixed to the end lid 1a. When the hydraulic chamber 9 is in a negative pressure state due to the movement of the piston 3, the oil suction valve 12 opens the communication hole 11 and causes the magnetorheological fluid to flow into the hydraulic chamber 9 through the communication path 34.

  The piston rod 2 is connected to the other of the support body or the supported body via a support member 8. The piston 3 is provided with a plurality of axial communication holes 15 in the circumferential direction that communicate with the hydraulic chambers 9 and 10 of the cylinder 1, and an oil absorption valve 16 is provided at the opening of the communication hole 15 on the hydraulic chamber 10 side. It has been. The oil absorption valve 16 is pressed against the piston 3 so as to close the communication hole 15 by a compressed spring 17 interposed between the end surface of the large-diameter portion of the piston rod 2. When the hydraulic chamber 10 is in a negative pressure state due to the movement of the piston 3, the oil suction valve 16 opens the communication hole 15 and causes the magnetorheological fluid to flow from the hydraulic chamber 9 into the hydraulic chamber 10.

The seal unit 4 is coupled to the outer side of the insertion side cover 1b of the piston rod 2 in the cylinder 1 so that the axis of the cylinder 1 coincides, and supports the piston rod 2 so as to be relatively movable while preventing leakage of the magnetorheological fluid. . The seal unit 4 includes a block body 18 that is airtightly fixed to the outside of the lid body 1b, an end lid 19 that is fixed to the block body 19, an attachment ring body 20, and a rubber film 21. The block body 18 includes a cylindrical rod insertion portion 18c having an insertion hole 18b that penetrates the piston rod 2 in a relatively movable manner, and a cylindrical portion that extends axially outward from the outer end of the block rod 18 so as to surround the piston rod 2 18a. The insertion hole 18 b is formed with a larger diameter than the outer diameter of the piston rod 2, and forms a gap with the outer periphery of the piston rod 2. The mounting ring 20 is formed with an annular gap between the outer periphery of the piston rod 2 so as to be continuous with the insertion hole 18b of the block body 18, and through the piston rod 2, and a cylindrical portion 20b of the cylindrical portion 20b. And an inner end flange portion 20c. The flange portion 20 c is fixed to the outer surface of the rod insertion portion 18 c of the block body 18. The rubber film 21, which is an elastic thin film body, is airtightly sandwiched between the outer peripheral surface of the rod insertion portion 18 c of the block body 18 and the flange portion 20 c of the mounting ring 20 at the outer peripheral edge, and the piston rod 2 at the inner peripheral edge. The intermediate portion is folded and held in a gap between the cylindrical portion of the mounting ring 20 and the outer periphery of the piston rod 2 so as to be extendable. The end lid body 19 is fixed to the cylindrical portion 18a of the block body 18 and supports the piston rod 2 slidably through a sealing material.
The piston rod 2 is composed of two component rods 2a and 2b that are screwed together in the axial direction, and the inner peripheral edge of the rubber film 21 is airtightly sandwiched between opposed end surfaces of the two component rods 2a and 2b. That is, as shown in FIG. 2, the inner end of the rubber film 21 is sandwiched and fixed between the front end surface of one of the constituent rods 2a and 2b of the piston rod 2 and the fixing cup 22 fitted and fixed thereto. The outer end portion is fitted into the annular groove 20a of the flange portion 20c of the mounting ring 20, and is sandwiched and fixed by abutment between the mounting ring body 20 and the rod insertion portion 18c of the block body 18. Rubber film 21 serves to gap flexibly developed on the piston rod regardless stroke position of the piston rod 2 of the piston rod 2 and the mounting ring member 20 or the rod insertion section 18c, a partition in the longitudinal axial direction, the hydraulic pressure chamber 10 The leakage to the outside due to the drawing of the magnetorheological fluid onto the piston rod 2 is blocked. Further, the rubber film 21 prevents contact between the piston rod 2 and the block 18 and the mounting ring 20 through the magnetic powder of the magnetorheological fluid.

  The bypass pipe 5 is arranged side by side in the same axial direction on the side of the cylinder 1. In this bypass pipe 5, a shaft rod 24 made of a magnetic material passes through the center line of the cylindrical case 23, and a plurality of annular electromagnets 26 are arranged in the axial direction without gaps with a flow passage 25 around the shaft rod 24. It is fixed. On the side surface of the shaft rod 24, annular magnetic poles 24 a protrude from the electromagnet 26 at substantially equal intervals in the axial direction. The electromagnet 26 is configured by being embedded in a state where a coil 26b is wound around the iron core 26a. A magnetic flux passes between the iron core 26a and the magnetic pole 23a, and forms a magnetic field in the radial direction of the iron core 26a in the flow passage 25. . The lead wire 26c of the electromagnet 26 is drawn out from a drawing port 27 at one end of the bypass pipe 5 and connected to a power supply unit (not shown). The flow passage 25 communicates with the communication passage 34 of the frame board 33 and the hydraulic chamber 10 and allows the magnetorheological fluid to flow therethrough.

The accumulator 6 includes a cylindrical case 28 having end lids in the axial direction . Inside the case 28 , an inner lid 29 is fitted in an airtight manner so as to be relatively movable in the axial direction, and a liquid chamber 6a in which a magnetorheological fluid is accommodated is formed. The inner lid 29 is pushed in a direction to narrow the liquid chamber 6a by a compressed double spring 30 interposed between the one end lid 28c of the case 28, and applies an internal pressure to the magnetorheological fluid in the liquid chamber 6a to change the temperature. When the magnetorheological fluid becomes excessive or deficient due to, for example, the liquid chamber 6a expands and contracts due to the displacement of the inner lid 29 due to the internal pressure. A gap is formed between the inner lid 29 and the inner peripheral wall of the case 28, and the rubber film 31 closes this gap . Inner end of the rubber film 31 is fixed by being sandwiched fixed cup 32 which is fitted and fixed thereto and the distal end surface of the inner lid 29, the cylindrical constituent member 28 a is the outer end is connected axially to each other, 28 b is fitted to one end face of the annular groove 28 d of the outer end is fixed by being sandwiched between the butt of the cylindrical constituent member 28 a and 28 b. The rubber film 31 flexibly unfolds the gap between the inner lid 29 and the case 28 on the inner lid 29 regardless of the stroke position of the inner lid 29, and partitions the front and rear in the axial direction. The leakage due to the drawing of magnetorheological fluid into is blocked.

  In this damper, when the support body and the supported body are relatively displaced, the piston rod 2 is pushed into the cylinder 1 or pulled out, and the piston 3 moves. Due to the movement of the piston 3, the volumes of the hydraulic chambers 9, 10 fluctuate, and the magnetorheological fluid therein flows through the bypass pipe 5. At this time, the flow of the magnetorheological fluid is throttled in the flow passage 25 in the bypass pipe 5, the magnetic field formed by the electromagnet 26 acts, the viscosity of the magnetorheological fluid increases, the flow resistance increases, and the piston 3 The movement of the support is restrained. The oil absorption valves 12 and 16 absorb the difference in the amount of magnetic viscous fluid coming and going due to the difference in volume fluctuations of the hydraulic chambers 9 and 10 when the piston 3 moves.

When the piston rod 2 moves in the direction (right direction in the drawing) pulled out from the cylinder 1, the rubber film 21 is interposed between the block body 18 or the mounting ring body 20 and the piston rod 2 in the seal unit 4. The drawing of the magnetorheological fluid from the hydraulic chamber 10 into the seal unit 4 is blocked, and leakage of the magnetorheological fluid to the outside is prevented. Further, since the rubber film 21 is flexibly deployed on the piston rod 2 and interposed between the piston rod 2 and the seal unit 4, direct contact between the block body 18 or the mounting ring body 20 and the piston rod 2 is prevented. In addition, since the magnetic powder of the magnetorheological fluid is prevented from entering between them, wear can be prevented and the sealing performance is maintained for a long time. This action is similarly performed by the rubber film 31 between the inner lid 29 and the case 28 in the accumulator 6.

  INDUSTRIAL APPLICABILITY The present invention is effective for a magnetorheological fluid flow type damper capable of preventing the sliding member from being worn and exhibiting the desired performance for a long period of time without using a packing / O-ring of the sealing material of the sliding portion.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 2a Constructing rod 2b Constructing rod 2c Connection part 3 Piston 4 Seal unit 5 Bypass pipe 6 Accumulator 6a Liquid chamber 9 Hydraulic chamber 10 Hydraulic chamber 18 Block 18b Large diameter part 20 Mounting ring 20a Annular groove 21 Rubber film 24a Annular Magnetic pole 25 Flow passage 26 Electromagnet 26a Iron core 28 Case 28d Annular groove 29 Inner lid 31 Rubber film

Claims (3)

A cylinder connected to one of the support or the support and filled with a magnetorheological fluid;
A piston that divides the inside of the cylinder into first and second hydraulic chambers and is movable in the axial direction within the cylinder;
A piston rod fixed to the piston and removably inserted into the cylinder and connected to the other of the support or the support; and
And a first hydraulic chamber and electromagnets forming a magnetic field for changing the flow resistance of the magnetorheological fluid on the way of the flow passage of the magnetorheological fluid flowing between the second hydraulic chamber of the cylinder In the magnetorheological fluid flow type damper
On the outside of the piston rod insertion side cover in the cylinder, a seal unit having an insertion hole for penetrating and supporting the piston rod in an axial direction is airtightly fixed.
An annular gap is formed between the insertion hole of the seal unit and the piston rod,
An intermediate portion of the elastic thin film body, which is airtightly fixed to the inner peripheral portion of the insertion hole at the outer peripheral edge portion and airtightly fixed to the outer peripheral portion of the piston rod at the inner peripheral edge portion, is folded so as to extend freely in the gap. Retained,
Thereby, the magnetorheological fluid flow damper, wherein Rukoto is prevented leakage of the magnetic viscous fluid to the outside from the hydraulic chamber of the cylinder. The seal unit has a rod insertion portion and a cylindrical portion and is hermetically fixed to the outside of the insertion-side lid body, and between the rod insertion portion of the block body and the outer periphery of the piston rod. The elastic thin film body interposed, the mounting ring fixed to the outside of the rod insertion portion of the block body, and the piston rod fixed to the cylindrical portion of the block body are slidably supported via the sealing material. An end lid,
The rod insertion part of the block body includes an insertion hole that forms an annular gap between the outer periphery of the piston rod and allows the piston rod to pass through.
The cylindrical portion of the block body extends outward from the outer end of the rod insertion portion, surrounding the piston rod,
The mounting ring includes a cylindrical portion that forms an annular gap between the outer periphery of the piston rod so as to be continuous with the insertion hole of the block body, and an inner end of the cylindrical portion. A flange portion fixed to the outer surface of the rod insertion portion of the block body on the side,
The elastic thin film body is airtightly sandwiched between the outer surface of the rod insertion portion of the block body and the flange portion of the mounting ring at the outer peripheral edge, and is airtightly fixed to the outer periphery of the piston rod at the inner peripheral edge. 2. The magnetorheological fluid flow type damper according to claim 1, wherein the intermediate portion is folded and held in a gap between the cylindrical portion of the mounting ring and the outer periphery of the piston rod so as to be extendable. The piston rod includes two structural rods screwed and connected to each other in the axial direction, and an inner peripheral edge portion of the elastic thin film body is airtightly sandwiched between opposed end surfaces of both structural rods. 3. A magnetorheological fluid flow damper according to 1 or 2.

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