JP6671074B2 - Magneto-rheological fluid device - Google Patents

Description

  According to the present invention, a magnetorheological fluid is interposed between members provided so as to be relatively rotatable with each other, and by changing the strength of a magnetic field applied to the magnetorheological fluid, torque transmitted between the members is made variable. The present invention relates to a magnetorheological fluid device.

  This type of magneto-rheological fluid device is disclosed in, for example, Patent Document 1. The magneto-rheological fluid device disclosed in the document (referred to as “rotation braking device” in the document) has a magnet-rheological fluid interposed between a disk (2) and a casing (5), and By changing the strength of the magnetic field applied to the viscous fluid, the torque transmitted between the disk and the casing can be changed. In this type of magnetorheological fluid device, a magnetorheological fluid is sealed in the device main body, and a sealing material is used in each gap so as to prevent the magnetorheological fluid from leaking from the device main body.

JP 2014-181778 A

  By the way, since the magnetic viscous fluid sealed in the apparatus main body expands in volume due to a rise in temperature, if the sealing force of the sealing material used in the apparatus main body is weak, the magnetic viscous fluid flows from the gap closed by the sealing material. May leak out. Of course, if the gap for fitting the sealing material is designed to be narrow and the force for pinching the sealing material is increased, the sealing force is increased and the leakage of the magnetic viscous fluid can be prevented.

  However, when the sealing material is provided in the gap between the relatively rotating members, it is not desirable to increase the force for sandwiching the sealing material. This is because the rotational resistance increases, and the minimum torque (hereinafter referred to as “base torque”) transmitted between the above members when no magnetic field is applied to the magneto-rheological fluid also increases. In general, an increase in the base torque narrows the range of use of the magneto-rheological fluid device, and therefore it is desired that the base torque be as close to zero as possible.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and when the magneto-rheological fluid thermally expands without increasing the base torque, the magneto-rheological fluid leaks from the gap sealed by the sealing material. It is an object of the present invention to provide a magneto-rheological fluid device capable of preventing or suppressing the problem.

  A magneto-rheological fluid device according to the present invention is enclosed in a device main body having a first part, a second part rotatably provided relative to the first part, and the first part and the second part. A magnetorheological fluid interposed between the first part and the second part, a magnetic field generator for applying a magnetic field to the magnetorheological fluid, and the magnetorheological fluid does not leak out of the apparatus main body. As described above, on the premise that a member that belongs to the first part and a sealing material that seals a gap between the members that belong to the second part are provided, and following the expansion and contraction of the volume of the magnetic viscous fluid, It is characterized by including a volume following operation unit that operates to expand and contract the volume of the space in which the magneto-rheological fluid is sealed.

  According to the magneto-rheological fluid device having such a configuration, a volume follow-up operation section is provided which operates to expand and contract the volume of the space in which the magneto-rheological fluid is sealed, following the expansion and contraction of the volume of the magneto-rheological fluid. Therefore, it is possible to prevent or suppress the leakage of the seal member due to the volume expansion of the magnetic viscous fluid without increasing the sealing force of the seal member.

  For example, the volume following operation unit is provided as a part of a member forming a space in which the magneto-rheological fluid is sealed, and the magneto-rheological fluid is sealed in accordance with expansion and contraction of the volume of the magneto-rheological fluid. It is possible to use a flexible member that is deformed so as to enlarge or reduce the volume of the space.

  Further, for example, the volume following operation section is configured to follow the expansion and contraction of the volume of the magnetorheological fluid by causing the piston and the piston to form a part of a member forming a space in which the magnetorheological fluid is sealed. And a cylinder portion fitted reciprocally so as to expand and contract the volume of the space in which the magnetorheological fluid is sealed.

  Further, the piston portion is provided with a flexible member that follows the expansion and contraction of the volume of the magneto-rheological fluid and deforms so as to expand and contract the volume of the space in which the magneto-rheological fluid is sealed. It is desirable to do.

  According to the magnetorheological fluid device of the present invention, it is possible to prevent or suppress leakage from the sealant due to volume expansion of the magnetorheological fluid without increasing the sealing force of the sealant. As a result, it is possible to prevent or suppress leakage from the sealing material due to volume expansion of the magnetic viscous fluid without increasing the base torque.

FIG. 2 is a cross-sectional view of the magneto-rheological fluid device according to the first embodiment of the present invention, cut along a plane including a rotation axis. It is sectional drawing which cut | disconnected and represented the magneto-rheological fluid apparatus which concerns on the modification of 1st Embodiment of this invention in the plane containing a rotation axis. FIG. 6 is a cross-sectional view illustrating a magneto-rheological fluid device according to a second embodiment of the present invention by cutting along a plane including a rotation axis. However, since the magneto-rheological fluid device is vertically symmetrical with respect to the center line, illustration below the center line is omitted. FIG. 4 is an enlarged view of a part X in FIG. 3. (A) is an enlarged view of a portion Y in FIG. 3, which is shown without omitting both sides of the center line. (B)-(d) is an explanatory view of the operation of each unit.

<First embodiment>
Hereinafter, a magneto-rheological fluid device according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a magneto-rheological fluid device 1 according to the present embodiment includes a first part 100 and a second part 200 provided so as to be relatively rotatable with each other, and a bearing 301 and a sealing material 302 interposed therebetween. , A spherical body 303, a magnetic viscous fluid 304, and the like.

  The first part 100 includes a shaft 101, a disk 102, and the like.

  The shaft 101 is rotatably supported via a bearing 301 in a shaft hole formed in a casing 203 described later. A cylindrical portion 103 is protruded from an end surface of the shaft 101 in the casing 203. A sphere 303 is fitted inside the cylindrical portion 103, and the diameter of the sphere 303 is set to be larger than the internal depth of the cylindrical portion 103. For this reason, a part of the sphere 303 protrudes from the cylindrical part 103 and is in contact with a sphere contact surface which is a part of a casing member 203B described later. It is desirable that a non-magnetic material be used for the shaft 101.

  The disc 102 has a through hole at the center, and the through hole is externally fitted to the cylindrical portion 103 of the shaft 101, and is bonded to the end surface of the shaft 101 and the outer peripheral surface of the cylindrical portion 103 using an adhesive. ing. For this reason, the disk 102 rotates integrally with the shaft 101. The disk 102 is made of a magnetic material.

  The second unit 200 includes a magnetic field generation unit 201, a volume following operation unit 202, and the like.

  The magnetic field generating unit 201 applies a magnetic field to a magnetic viscous fluid 304 interposed between the disk 102 and the casing 203. In the present embodiment, the magnetic field generator 201 includes a casing 203, a coil 204, a bobbin 205, and the like.

  The casing 203 is composed of two members 203A and 203B made of a magnetic material and functions as a yoke. The casing 203 illustrated in FIG. 1 is constructed by combining two members 203A and 203B and fastening the outer peripheral portion with a plurality of (only one is shown in FIG. 1) screws 206. In the casing 203, a space for fitting the coil 204 and the bobbin 205, and a space for rotatably housing the shaft 101 and the disk 102 are formed.

  As described above, the bearing 301 is fitted into the shaft hole of one casing member 203A, and a seal member 302 made of an O-ring is fitted at a position closer to the disk 102 than the bearing 301. . The sealant 302 seals a gap between the shaft 101 and a shaft hole formed in the casing member 203A, thereby preventing leakage of the magnetorheological fluid 304.

  On the other casing member 203B, a concave portion 207 recessed from the outside to the inside is formed on an extension of the shaft 101. The concave portion 207 illustrated in FIG. 1 is a cylindrical concave portion, and accommodates a rotor 102 that accommodates the end portion of the disk 102, the shaft 101, and the like through a plurality of communication passages 208 formed in the casing member 203B. It communicates with the space 209. The communication path 208 illustrated in FIG. 1 is formed as two cylindrical holes.

  The coil 204 is wound around a bobbin 205 fitted in the casing 203, and an electric current is supplied from the outside by an electric wire 306 so that the electric current value can be controlled. When a current is applied to the coil 204, a magnetic circuit is formed on the casing 203, the disk 102, and the magneto-rheological fluid 304 interposed therebetween along the direction indicated by the arrow P in FIG. Reference numeral 211 denotes an annular seal member for preventing the magnetorheological fluid 304 from leaking outside through gaps between the both side surfaces of the bobbin 205 and the casings 203A and 203B.

  The volume following operation unit 202 is made of, for example, a flexible member, and is provided so as to close the opening of the concave portion 207 formed in the casing member 203B. The volume follow-up operation section 202 constitutes a part of a member forming a sealed space 307 of the magnetorheological fluid in the apparatus main body 2, and follows the expansion and contraction of the volume of the magnetorheological fluid 304, and 307 operates to expand or contract the volume. In the example shown in FIG. 1, a rubber diaphragm is employed as the volume follow-up operation section 202. However, the material of the diaphragm may be other than rubber as long as the following operation is possible.

  The volume following operation unit 202 shown in FIG. 1 has an outer peripheral portion attached to a casing 203 with an adhesive or an adhesive so that the magnetic viscous fluid 304 does not leak outside, and further has a plate-like member made of, for example, a metal material. It is pressed against the casing 203 by 308. The plate-shaped member 308 is fixed to the casing 203 with a screw 206, and a circular hole 308a is formed in a central portion thereof so as not to hinder the operation of the volume following operation section 202. The hole 308a shown in FIG. 1 corresponds to the shape and size of the opening of the recess 207.

  The magnetorheological fluid 304 is sealed in a magnetorheological fluid sealing space 307 in the apparatus main body 2 composed of the first part 100 and the second part 200. In FIG. 1, an area shaded in gray represents the enclosed space 307 of the magnetic viscous fluid. The magnetic viscous fluid 304 is interposed in gaps 307a and 307b between the disk 102 belonging to the first part 100 and the casing 203 belonging to the second part 200, and transmits torque according to the viscosity therebetween.

  The magnetic viscous fluid 304 is a liquid in which magnetic particles are dispersed in a dispersion medium. In particular, a liquid in which the magnetic particles are composed of nano-sized metal particles (metal nanoparticles) can be used. The magnetic particles are made of a magnetizable metal material, and the metal material is not particularly limited, but a soft magnetic material is preferable. Examples of the soft magnetic material include alloys such as iron, cobalt, nickel, and permalloy. The dispersion medium is not particularly limited, but an example is a hydrophobic silicone oil. The blending amount of the magnetic particles in the magnetorheological fluid may be, for example, 3 to 40 vol%. Various additives can also be added to the magnetorheological fluid to obtain various desired properties.

  In the magnetorheological fluid device 1 having the above configuration, when a current is applied to the coil 204, a magnetic circuit is formed in the casing 203 along the direction indicated by the arrow P in FIG. , 307b develop a viscosity (shear stress) according to the strength of the magnetic field in the magnetic viscous fluid 6. As a result, torque is transmitted between the first portion 100 (the shaft 101 and the like) and the second portion 200 (the casing 203 and the like) in accordance with the magnitude of the current value applied to the coil 204.

  In the magneto-rheological fluid device 1 having the above configuration, when the volume of the magneto-rheological fluid 304 expands due to a temperature rise, the volume follow-up operation part 202 which forms a part of the member forming the enclosed space 307 of the magneto-rheological fluid, Following the volume expansion, the state changes from the state shown by the solid line to the state shown by the two-dot chain line in FIG. Accordingly, the volume of the enclosed space 307 for the magnetic viscous fluid is enlarged, and the internal pressure in the space 307 is prevented from rising. As a result, the leakage of the magnetic viscous fluid 304 from the gap between the casing 203 and the shaft 101, which is sealed by the sealing material 302, is prevented or suppressed without increasing the sealing force of the sealing material 302. .

  Thereafter, when the temperature of the magnetorheological fluid 304 decreases and returns to the original temperature, the volume following operation unit 202 follows the volume contraction of the magnetorheological fluid 304 and changes from a state shown by a two-dot chain line in FIG. It returns to the original state shown.

  As is apparent from the above description, according to the magneto-rheological fluid device 1 according to the first embodiment of the present invention, the sealing caused by the volume expansion of the magneto-rheological fluid can be performed without increasing the sealing force of the sealing member 302. Leakage from the member 302 can be prevented or suppressed. That is, it is possible to prevent or suppress leakage from the sealant 302 due to volume expansion of the magnetorheological fluid without increasing the base torque.

<Modification of First Embodiment>
In the magneto-rheological fluid device 1, the volume following operation section 202 formed of a diaphragm is pressed against the casing member 203B by the plate member 308. However, the plate member 308 is eliminated, and as shown in FIG. An annular groove 207a may be formed on the side wall of the concave portion 207, and the volume following operation portion 202A made of a diaphragm may be fitted into the annular groove 207a. By doing so, the above-described effects can be obtained.

<Second embodiment>
Hereinafter, a magneto-rheological fluid device according to a second embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 3 to 5, the magneto-rheological fluid device 1 </ b> A according to the present embodiment includes a first part 400 and a second part 500 provided so as to be relatively rotatable with each other, and a bearing 601 interposed therebetween. A seal member 602, a magnetic viscous fluid 604, and the like are provided.

  The first part 400 mainly includes a shaft 401, disk members 404 and 405, a first outer member 406, a second outer member 407, a cover member 408, an outer disk 403 (see FIG. 4), and the like.

  The shaft 401 is rotatably supported via a bearing 601 in a shaft hole formed in a bobbin 505 described later. It is desirable that a non-magnetic material be used for the shaft 401.

  The disk members 404 and 405 are integrated with the shaft 401. The first outer casing member 406 and the second outer casing member 407 are both made of a magnetic material, and have a shape that wraps a coil 508 and the like described later. The cover member 408 covers the outer peripheral surfaces of the first outer member 406 and the second outer member 407 to a part of the side surface of the first outer member 406 and is fixed to the first outer member 406 by bolts. The gaps between the cover member 408 and the first and second outer casing members 406 and 407 are sealed by O-rings 409, respectively.

  The outer disk 403 is formed of a magnetic annular plate, and as shown in FIG. 4, is alternately arranged in parallel with the inner disk 509 belonging to the second part 500 and also formed of a magnetic annular plate in the rotation axis direction. . A minute gap is secured between the inner diameter side of the outer disk 403 and the outer diameter side of the inner disk 509, and the magnetorheological fluid 604 is interposed in the minute gap. Note that spacers 411 made of an annular plate are interposed between the outer disks 403 in order to secure a certain minute gap between the outer disk 403 and the inner disk 509. Further, they are fastened by bolts 412 while being interposed between the first outer member 406 and the second outer member 407. On the other hand, spacers 502 made of an annular plate are also interposed between the inner disks 509, and these are fastened by bolts 506 via a member 507 to the vicinity of the outer periphery of a bobbin 505 described later.

  The second unit 500 includes a part of the magnetic field generating unit 501, a volume following operation unit 502, an input / output member 503, and the like.

  The magnetic field generating unit 501 is for applying a magnetic field to the magnetic viscous fluid 604 interposed between the outer disk 403 belonging to the first part 400 and the inner disk 509 belonging to the second part 500. , A coil 508, a bobbin 505, and a first outer packaging material 406 and a second outer packaging material 407 functioning as a yoke.

  A coil 504 is wound around the bobbin 505. The bobbin 505 is made of a magnetic material and also functions as a yoke.

  A current is supplied to the coil 508 from an external source via an electric wire (not shown) so that the current value can be controlled. When a current is applied to the coil 508, a magnetic circuit is formed on the first outer member 406, the second outer member 407, the bobbin 505, the outer disk 403, and the inner disk 509 along the direction indicated by the arrow P in FIG. Then, a magnetic field is applied to the magnetorheological fluid 604 interposed in the minute gap between the outer disk 403 and the inner disk 509.

  The input / output member 503 is bolted to a shaft 511 integrally formed at the center of the bobbin 505. The input / output member 503 and the shaft portion 511 are rotatably supported via a bearing 601 in a shaft hole formed in the second outer member 407. Further, in a gap between the second outer casing member 407 belonging to the first part 400 and the shaft part 511 belonging to the second part 500, a seal member 602 (an O-ring is a seal member illustrated in FIG. 3) for sealing the gap is provided. Is provided.

  When a current is applied to the coil 508 in the magnetic viscous fluid device 1A having the above configuration, a magnetic circuit is formed along the direction indicated by the arrow P in FIG. 3 and intervenes in the minute gap between the outer disk 403 and the inner disk 509. Viscosity (shear stress) corresponding to the strength of the magnetic field appears in the magneto-rheological fluid 604. Thus, torque transmission according to the magnitude of the current value applied to the coil 504 is performed between the first part 400 and the second part 500.

  The volume following operation portion 502 constitutes a part of a member forming a sealed space 605 of the magnetorheological fluid in the apparatus main body 2A composed of the first portion 400 and the second portion 500, and expands the volume of the magnetorheological fluid 604. Following the contraction, it operates so as to enlarge or reduce the volume of the enclosed space 605 for the magnetic viscous fluid.

  In the example shown in FIG. 3 and FIG. 5 which is an enlarged view of a portion Y in FIG. 3, the volume following operation portion 502 includes a piston portion 513 and a cylinder portion 512, and the piston portion 513 It is fitted in the cylinder part 512 so as to be able to reciprocate so as to expand and contract the volume. The cylinder portion 512 is formed on an extension of the shaft 401.

  The piston portion 513 has a rubber diaphragm 516 (flexible member) that is deformed by a pressure difference between the inside and outside at a part thereof (a center portion in the illustrated example). 5 includes annular members 517 and 518, which are overlapped with each other and fastened by screws 513, an O-ring 521 mounted in a groove formed on the outer periphery of the annular member 517, and It is composed of a diaphragm 516 sandwiched between two annular members 517, 518. The piston portion 513 can reciprocate between a C-shaped snap ring 522 fitted in the cylinder portion 512 and an end wall 512a of the cylinder portion 512.

  In the volume following operation section 502, the entire piston section 513 moves in the cylinder section 512 following the expansion and contraction of the volume of the magnetic viscous fluid 604, thereby expanding or reducing the volume of the magnetic viscous fluid enclosed space 605. . Further, the diaphragm 516 of the biston portion 513 is deformed in the film thickness direction in accordance with the expansion and contraction of the volume of the magnetic viscous fluid 604, so that the volume of the enclosed space 605 of the magnetic viscous fluid can be enlarged or reduced. It has become. Note that the material of the diaphragm 516 may be other than rubber as long as the above-described following operation can be performed. An external communication passage 522 (see FIG. 3) communicating with the outside of the apparatus main body 2A is formed on the side of the cylinder portion 512 opposite to the sealed space 605, and the pressure on the back side of the piston portion 513 is always atmospheric pressure. Becomes

  As the magnetorheological fluid 604, the same one as the magnetorheological fluid 304 described in the first embodiment is used.

  In the magnetorheological fluid device 1A having the above configuration, when the magnetorheological fluid 604 expands in volume due to a rise in temperature, the volume following operation part 502 which forms a part of the member forming the enclosing space 605 of the magnetorheological fluid is moved by the magnetorheological fluid 604. It operates following volume expansion. In the present embodiment, when the magnetorheological fluid 604 is at a predetermined temperature (for example, 10 ° C.), as shown in FIG. 5A, the piston 513 is located on the sealed space 605 side, and the temperature of the magnetorheological fluid 604 is lower. When the volume rises and the volume expands, the diaphragm 516 is deformed as shown in FIG. Accordingly, the volume of the enclosed space 605 for the magnetic viscous fluid is increased, and the pressure inside the space 605 is prevented from rising. Further, when the temperature of the magnetorheological fluid 604 rises and its volume expands, the entire piston portion 513 moves in the cylinder portion 512 as shown in FIG. As a result, the volume of the sealed space 605 is further increased, and a pressure increase is continuously prevented. As described above, the diaphragm 516 of the piston portion 513 and the entire piston portion 513 operate to prevent a pressure increase in the sealed space 605, so that the sealing material 602 can be sealed without increasing the sealing force of the sealing material 602. The leakage of the magnetic viscous fluid from the gap between the second outer casing member 407 and the shaft portion 511 is prevented or suppressed.

  Thereafter, when the temperature of the magnetorheological fluid 504 decreases and returns to the original temperature, the volume following operation section 502 follows the volume contraction of the magnetorheological fluid 504 and follows FIG. 5 (d), FIG. The operation is performed in the order shown in FIG. 5A to return to the original state.

  As is clear from the above description, according to the magneto-rheological fluid device 1A according to the present embodiment, the leakage from the seal member 602 due to the volume expansion of the magneto-rheological fluid can be achieved without increasing the sealing force of the seal member 602. Can be prevented or suppressed. That is, it is possible to prevent or suppress leakage from the sealant 602 due to volume expansion of the magnetorheological fluid without increasing the base torque.

<Modification 1 of Second Embodiment>
In the second embodiment described above, the volume following operation unit 502 first deforms the diaphragm 516 when the magnetic viscous fluid 604 expands in volume, and then moves the entire piston unit 513. By designing to reduce the frictional resistance of the O-ring 521 to the cylinder portion 512, when the volume of the magnetorheological fluid 604 expands, first, the entire piston portion 513 can be moved, and then the diaphragm can be deformed. . In this case, when the volume of the magnetorheological fluid 604 expands, the state changes in the order of FIGS. 5A, 5C, and 5D, and when the volume of the magnetorheological fluid 604 contracts, FIG. The state changes in the order of 5 (d), FIG. 5 (c), and FIG. 5 (a) and returns to the original state.

  Further, the frictional resistance of the O-ring 521 to the cylinder 512 may be set so that the movement of the piston 513 and the deformation of the diaphragm 516 proceed simultaneously.

<Modification 2 of Second Embodiment>
In the second embodiment described above, the piston 513 has the diaphragm 516. However, the diaphragm 516 is eliminated, and the piston 513 is made of a member that is not deformed by pressure. It is also possible to enlarge or reduce the volume of the sealed space 605 for the viscous fluid.

  For example, the present invention varies a torque transmitted between the members by interposing a magnetorheological fluid between members provided so as to be relatively rotatable with each other and changing the strength of a magnetic field applied to the magnetorheological fluid. The present invention can be applied to a magnetic viscous fluid device.

1,1A Magneto-rheological fluid device 2,2A Device main body 100,400 First part 101 Shaft (member belonging to first part)
200,500 Second part 203A Casing member (member belonging to the second part)
304, 604 Magneto-rheological fluid 201, 501 Magnetic field generation section 302, 602 Sealing material 202, 502 Volume following operation section 307, 605 Magneto-rheological fluid enclosing space 407 Second outer member (member belonging to the first part)
511 Shaft (member belonging to the second part)
512 Cylinder part 513 Piston part

Claims (2)

Part 1;
A second part provided rotatably relative to the first part;
A magneto-rheological fluid sealed in a device body having the first part and the second part, and interposed between the first part and the second part;
A magnetic field generator for applying a magnetic field to the magnetorheological fluid,
A sealing material for sealing a gap between the member belonging to the first part and the member belonging to the second part so that the magnetic viscous fluid does not leak out of the apparatus main body;
In the magneto-rheological fluid device provided with
The magneto-rheological fluid to follow the expansion and contraction of the volume of, Bei give a volume following operation portion to which the magnetorheological fluid is operable to reduce a larger volume of the encapsulated space,
The volume following operation unit,
A piston part forming a part of a member forming a space in which the magneto-rheological fluid is enclosed,
A cylinder portion fitted with the piston portion so as to reciprocate so as to expand and contract the volume of the space in which the magnetorheological fluid is sealed, following the expansion and contraction of the volume of the magnetorheological fluid;
Has,
A flexible member is provided at a center portion of the piston portion, the flexible member deforming so as to expand and contract the volume of the space in which the magnetorheological fluid is sealed, following the expansion and contraction of the volume of the magnetorheological fluid. A magneto-rheological fluid device characterized by the following. The magneto-rheological fluid device according to claim 1,
An external communication path communicating with the outside is formed on the side of the cylinder portion opposite to the space in which the magneto-rheological fluid is sealed, so that the pressure on the back side of the piston portion is always atmospheric pressure.
A magnetic viscous fluid device characterized by the above.

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