JP6201176B2 - Rotating braking device - Google Patents

Description

  The present invention relates to a rotary braking device that changes torque transmitted between an input side and an output side via a magnetorheological fluid by changing the strength of a magnetic field applied to the magnetorheological fluid.

  This type of rotary braking device is disclosed in, for example, Patent Document 1. The rotary braking device of the same document is configured such that a large number of disks are fixed to a rotating shaft at predetermined intervals in the axial direction, and these disks are incorporated in a casing so as to be relatively rotatable. A magnetorheological fluid is enclosed in the casing, and an electromagnet is provided for applying a magnetic field to the magnetorheological fluid. In this rotary braking device, if a current is applied to the electromagnet coil, the viscosity (shear stress) of the magnetorheological fluid increases according to the magnitude of the current, and the torque transmitted between the rotating shaft and the casing increases. Become.

  Since the magnetorheological fluid has low magnetic permeability, it is desirable to make the gap between the disk and the surface (casing) facing the disk as small as possible. That is, by reducing the gap, the required magnetomotive force can be reduced, and the viscosity of the magnetorheological fluid can be increased efficiently according to the magnitude of the current.

JP 2008-202744 A

  However, in order to reduce the gap between the disk surface and the surface facing the disk (for example, 0.1 mm or less), it is necessary to increase the dimensional accuracy of the parts related to the gap, which increases the processing cost. Occurs. For example, in the case of the rotational braking device disclosed in Cited Document 1, the thickness accuracy of a disk (referred to as “Plate 3” in Cited Document 1), a spacer, a case side plate, etc. High dimensional accuracy is required in many places, such as the accuracy of the fitting part, and the processing cost increases.

  The present invention was devised in view of such a problem, and it is possible to reduce the machining cost by reducing the places where it is necessary to increase the dimensional accuracy in order to reduce the gap between the disk and the surface facing the disk. An object of the present invention is to provide a rotary braking device that can be realized.

In order to solve the above-mentioned problems, a rotary braking device of the present invention includes a rotary shaft, a disc made of a magnetic material having an end portion of the rotary shaft connected to a central portion of one surface, and the disc. The rotating member is formed so that a facing member made of a magnetic material having opposing surfaces facing each other in parallel through a minute gap with respect to the other surface and a magnetic path penetrating the minute gap when a current is applied. and a coil disposed concentrically about the axis of the shaft, the magnetic fluid filled in the minute gap, assume that wherein the magnetic center of the other surface of the disc A concave portion into which a sphere made of a non-magnetic material for preventing road interference is fitted is formed, the sphere is fitted to the deepest position with respect to the concave portion, and a part of the sphere is the other surface of the disc Projecting a predetermined amount in the axial direction from It is characterized in that said small gap is formed me.

  According to the rotary braking device having such a configuration, the gap between the other surface of the disk and the facing surface of the facing member is determined solely by the protruding amount of the sphere from the other surface of the disk. The gap can be made a minute gap of a predetermined value or less only by improving the accuracy of the diameter of the sphere, the accuracy of the shape of the recess, and the squareness accuracy between the other surface of the disk and the axis.

  For example, the rotary braking device of the present invention has the above-described configuration, and the coil is disposed on one surface side of the disk, and the inner peripheral side, the outer peripheral side, and the anti-disc of the coil. A yoke is provided that surrounds the sides and has opposing surfaces formed on the inner and outer peripheral sides of one surface of the disk at both ends that become magnetic poles when current is applied to the coil. It may be what has been done.

  Further, the rotary braking device of the present invention has the above-described configuration, for example, and the disk has a through-hole penetrating in the plate thickness direction in the same radius range as the radius range where the coil is disposed. It is desirable that a plurality are formed in the circumferential direction.

  According to the present invention, it is possible to reduce locations where it is necessary to increase dimensional accuracy in order to reduce the gap between the other surface of the disk and the facing surface of the facing member, thereby reducing processing costs. it can.

It is sectional drawing which cut | disconnected and represented the rotary braking device which concerns on the 1st Embodiment of this invention by the plane containing an axis line. It is sectional drawing which cut | disconnected and represented the rotary braking device which concerns on the 2nd Embodiment of this invention by the plane containing an axis line. It is sectional drawing which cut | disconnected and represented the rotary braking device which concerns on the 3rd Embodiment of this invention by the plane containing an axis line. It is a figure which shows the case where a through-hole is not provided in the rotary braking device which concerns on the 3rd Embodiment of this invention.

<First Embodiment>
Hereinafter, a rotary braking device according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a rotary braking device 100 according to the first embodiment of the present invention is composed of a rotary shaft 1, a disc 2, a facing member 3, a coil 4, a casing 5, a magnetorheological fluid 6, and the like. .

  The end of the rotating shaft 1 is connected perpendicularly to the center of one surface 2a (hereinafter also referred to as “back surface 2a”) of the disc 2. A first different-diameter portion 13 having a diameter larger than that of the general portion 11 of the rotary shaft 1 is formed at the end of the rotary shaft 1. A second different diameter portion 14 having a smaller diameter than the first different diameter portion 13 and a larger diameter than the general portion 11 is formed. An O-ring groove 15 is formed in the first different diameter portion 13, and an O-ring 71 for preventing the magnetorheological fluid 6 from leaking to the outside is fitted in the O-ring groove 15. The rotating shaft 1 is rotatably supported in the shaft hole 51 of the casing 5 through a bearing 72. The bearing 72 is externally fitted to the general portion 11 of the rotary shaft 1, and the side surface on the disc 2 side is engaged with a step portion formed at the boundary between the general portion 11 and the second different diameter portion 14. Has been. Further, the side surface of the bearing 72 opposite to the disc 2 is engaged with a collar 53 formed in the shaft hole 51.

  The disk 2 is connected to the end of the rotating shaft 1 as described above, and can rotate relative to the facing member 3, the casing 5 and the like around the axis N integrally with the rotating shaft 1. . The disc 2 is made of a magnetic material such as iron.

  The facing member 3 is made of a magnetic material and has flat facing surfaces 31A and 31B that face the other surface 2b of the disc 2 (hereinafter also referred to as “surface 2b”) in parallel with a minute gap 61 therebetween. doing. Here, the minute gap 61 is not particularly limited numerically, but is preferably a gap of 0.1 mm or less, for example. In the facing member 3, an annular groove 32 centered on the axis N is formed in order to dispose the coil 4. The groove 32 separates the facing surface into a facing surface 31A on the inner diameter side and a facing surface 31B on the outer diameter side. A fitting part 33 with the casing 5 is formed on the outer peripheral part of the facing member 3.

  The coil 4 is disposed along the groove 32 formed in the facing member 3. An arbitrary current can be supplied to the coil 4 by a current supply device (not shown). The current supply device may be mounted on any part of the facing member 3 and the casing 5, or may be provided separately from these.

  The casing 5 is fitted to the facing member 3 so as to cover the back surface 2a and the outer peripheral surface 21 of the disc 2, and is fastened with a bolt or the like (not shown) so as not to cause relative rotation with respect to the facing member 3. The casing 5 is made of a non-magnetic material, and as described above, has the shaft hole 51 in the center portion, and has the fitting portion 52 on the outer peripheral portion for fitting with the fitting portion 33 of the facing member 3. .

  The magnetorheological fluid 6 is filled in a minute gap 61 between the surface 2 b of the disk 2 and the facing surfaces 31 </ b> A and 31 </ b> B of the facing member 3. The whole magnetorheological fluid 6 is enclosed in a gap between the disc 2, the casing 5, and the facing member 3. The magnetorheological fluid 6 is a liquid in which magnetic particles are dispersed in a dispersion medium, and 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, and a hydrophobic silicone oil can be given as an example. 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 in order to obtain various desired properties.

  A concave portion 22 that is depressed in the direction of the axis N is formed at the center of the surface 2b of the disk 2. A spherical body 8 made of a nonmagnetic material such as stainless steel is fitted into the concave portion 22. The sphere 8 is fitted to the recess 22 to the deepest position, and a part of the sphere 8 protrudes from the surface 2b of the disk 2 by a predetermined amount in the direction of the axis N and abuts against the facing surface 31A of the facing member 3. . As a result, a minute gap 61 is always formed between the surface 2 b of the disk 2 and the facing surfaces 31 </ b> A and 31 </ b> B of the facing member 3. In the example shown in FIG. 1, the recess 22 is a cylindrical cavity, and a part of the sphere 8 is in the direction of the axis N from the surface 2 b of the disk 2 in a state where the sphere 8 is in contact with the bottom surface 22 a of the recess 22. Protrudes by a predetermined amount.

  In the rotary braking device 100 having the above configuration, when a current is applied to the coil 4 by the current supply device, a magnetic path is formed in the disc 2 and the facing member 3 along the directions indicated by the arrows Pa and Pb. This magnetic path penetrates the magnetorheological fluid 6 filled in the minute gap 61. As a result, the magnetorheological fluid 6 in the minute gap 61 develops a viscosity (shear stress) corresponding to the strength of the magnetic field, and the transmission torque between the disc 2 and the facing member 3 is the strength of the magnetic field. It grows according to.

  According to the rotary braking device 100 described above, the minute gap 61 filled with the magnetorheological fluid 6 is determined exclusively by the amount of protrusion of the sphere 8 from the surface 2b of the disk 2. In addition, a minute gap 61 of 0.1 mm or less can be formed by only increasing the diameter accuracy of the sphere 8, the shape accuracy of the recess 22 (for example, depth dimension accuracy), and the squareness accuracy between the surface 2 b of the disk 2 and the axis N to some extent. Can be formed. And since the space | interval which should improve a dimensional accuracy in order to make the clearance gap between the disc 2 and opposing surface 31A, 31B into a micro clearance gap of 0.1 mm or less becomes lower than before, processing cost can be reduced.

  Further, according to the rotary braking device 100 according to the first embodiment, since the spherical body 8 made of a non-magnetic material is fitted into the concave portion 22 at the center of the disc 2, the magnetic paths Pa and Pb are the disc 2 It becomes difficult to interfere with each other at the center. For this reason, a strong magnetic field can be efficiently applied to the minute gap 61. Of course, the larger the diameter of the sphere 8 (for example, the diameter of the sphere 8 is 70% to 100% of the thickness of the disk 2), the magnetic paths Pa and Pb are less likely to interfere with each other at the center of the disk 2, and the efficiency A good and strong magnetic field can be applied to the minute gap 61.

<Second Embodiment>
Hereinafter, a rotary braking device according to a second embodiment of the present invention will be described with reference to the drawings. Hereinafter, differences from the first embodiment will be mainly described, and the same configurations as those of the first embodiment will be denoted by the same reference numerals in the drawings, and description thereof will be omitted.

  As shown in FIG. 2, the rotary braking device 100A according to the second embodiment includes a rotating shaft 1, a disc 2A, a facing member 3A, a coil 4, a casing 5A, a magnetorheological fluid 6, and the like.

  The disc 2A is connected to the end of the rotating shaft 1, and is rotatable relative to the facing member 3A, the casing 5A and the like around the axis N integrally with the rotating shaft 1. A plurality of annular recesses 23 are formed on the outer peripheral side (outer diameter side of the coil 4) of the surface 2b of the disc 2A. The number of the concave stripes 23 may be single or many. Also in this embodiment, the disc 2A is made of a magnetic material such as iron.

  The facing member 3A is made of a magnetic material and has facing surfaces 34A and 34B that face the surface 2b of the disk 2A in parallel with a minute gap 61 therebetween. In the facing member 3 </ b> A, an annular groove 32 centered on the axis N is formed in order to dispose the coil 4. By the groove 32, the facing surface is divided into a facing surface 34A on the inner diameter side and a facing surface 34B on the outer diameter side. In addition, on the facing surface 34B of the facing member 3A, a plurality of annular ridges 35 fitted to the ridges 23 are formed, and a predetermined gap is secured between the ridges 23 and the ridges 35. . The number of ridges 35 corresponds to the number of ridges 23. The facing member 3A is fitted inside a casing 5A, which will be described later, and is pressed against the disk 2A by an annular pressing plate 55 fastened to the casing 5A with a bolt.

  The casing 5A covers the back surface 2a and the outer peripheral surface 21 of the disc 2A, is fitted on the outer peripheral portion of the facing member 3A, and is fixed so as not to cause relative rotation with respect to the facing member 3A. Also in this embodiment, the casing 5A is made of a nonmagnetic material and has a shaft hole 51 through which the rotary shaft 1 is passed at the center.

  The magnetorheological fluid 6 is filled in a minute gap 61 between the surface 2b of the disk 2A and the facing surfaces 34A and 34B of the facing member 3A, or a gap between the concave strip 23 and the convex strip 35, and the magnetic viscous fluid 6 as a whole. Is enclosed in a gap between the disc 2A and the casing 5A and the facing member 3A. The composition of the magnetorheological fluid 6 is as described in the first embodiment.

  In the rotary braking device 100A having the above configuration, when a current is applied to the coil 4 by the current supply device, a magnetic path is formed in the disc 2A and the facing member 3A as indicated by arrows Pa and Pb. This magnetic path is a gap between the magnetic viscous fluid 6 filled in the minute gap 61 between the surface 2b of the disk 2A and the facing surfaces 34A and 34B of the facing member 3A, and the gap between the side surface of the concave strip 23 and the side surface of the convex strip 35. It penetrates through the magnetorheological fluid 6 filled in the. As a result, the viscosity (shear stress) corresponding to the strength of the magnetic field is expressed in the magnetorheological fluid 6 present in these locations, and the transmission torque between the disc 2A and the facing member 3A is increased. It grows depending on the size. In particular, since the magnetic path penetrates the magnetorheological fluid 6 filled in the gap between the side surface of the concave strip 23 and the side surface of the convex strip 35, the transmission torque can be efficiently transmitted as compared with the rotary braking device 100 according to the first embodiment. Can be improved.

<Third Embodiment>
Hereinafter, a rotary braking device according to a third embodiment of the present invention will be described with reference to the drawings. Hereinafter, differences from the first embodiment will be mainly described, and the same configurations as those of the first embodiment will be denoted by the same reference numerals in the drawings, and description thereof will be omitted.

  As shown in FIG. 3, the rotary braking device 100B according to the third embodiment includes a rotating shaft 1B, a disc 2B, a first facing member 3B, a second facing member 3C, a coil 4, a casing 5B, and a magnetorheological fluid 6 Etc.

  The end of the rotary shaft 1B is connected perpendicularly to the center of the back surface 2a of the disc 2B. A first different diameter portion 13 having a diameter larger than that of the general portion 11 of the rotation shaft 1B is formed at an end portion of the rotation shaft 1B. A second different diameter portion 14 having a diameter smaller than that of the first different diameter portion 13 and larger than that of the general portion 11 is formed. An O-ring groove 15 is formed in the first different diameter portion 13, and an O-ring 71 is fitted in the O-ring groove 15. The rotary shaft 1B is rotatably supported in the shaft hole 51 of the casing 5B via a bearing 72. The bearing 72 is externally fitted to the general portion 11 of the rotary shaft 1B, and the side surface on the disk 2 side is engaged with a step portion formed at the boundary between the general portion 11 and the second different diameter portion 14. Has been.

  As described above, the disc 2B is connected to the end of the rotating shaft 1B, and around the axis N integrally with the rotating shaft 1B, the first facing member 3B, the second facing member 3C, the casing 5B, etc. The relative rotation is possible. A plurality of through holes 25 penetrating in the plate thickness direction are formed in the circular plate 2B in the circumferential direction within the same radius range as the radius range Z in which the coil 4 is disposed. In this embodiment, the disc 2B is made of a magnetic material.

  The first facing member 3B is made of a magnetic material, and has a facing surface 36 that faces the surface 2b of the disk 2B in parallel with a minute gap 61 therebetween. The first facing member 3B is fitted inside the cylindrical casing 5B, and is pressed against the disc 2B side by an annular pressing plate 55 fastened to the casing 5B with a bolt.

  The second facing member 3C is made of a magnetic material and has facing surfaces 37A and 37B that face the back surface 2a of the disc 2B in parallel with a predetermined gap therebetween. The second facing member 3 </ b> C has a shaft hole 51 for passing the rotating shaft 1 </ b> B at the center, and also has an annular groove 32 centered on the axis N for disposing the coil 4. By the groove 32, the facing surface is divided into a facing surface 37A on the inner diameter side and a facing surface 37B on the outer diameter side. That is, the second facing member 3C has a cross-sectional shape surrounding the inner peripheral side, the outer peripheral side, and the anti-disc 2B side of the coil 4, and the inner peripheral side of the back surface 2a of the disc 2B at both ends and Opposite surfaces 37A and 37B are provided on the outer peripheral side. The second facing member 3 </ b> C functions as a yoke whose opposite ends (opposing surfaces 37 </ b> A and 37 </ b> B) serve as magnetic poles when a current is applied to the coil 4. The second facing member 3C is fitted inside a cylindrical casing 5B, and is fixed to an annular holding plate 56 fastened to the casing 5B with a bolt.

  The coil 4 is disposed along the groove 32 formed in the second facing member 3C. An arbitrary current can be supplied to the coil 4 by a current supply device (not shown). The current supply device may be mounted on any part of the first facing member 3B, the second facing member 3C, and the casing 5B, or may be provided separately from these.

  The casing 5B is made of a cylindrical member as described above, and is made of a nonmagnetic material.

  The magnetorheological fluid 6 is filled in a minute gap 61 between the surface 2b of the disk 2B and the facing surface 36 of the facing member 3B. The entire magnetorheological fluid 6 is enclosed in a gap between the disc 2B and the first facing member 3B, the second facing member 3C, and the casing 5B. The composition of the magnetorheological fluid 6 is as described in the first embodiment.

  In the rotary braking device 100B having the above configuration, when a current is applied to the coil 4 by the current supply device, the disc 2B, the first facing member 3B, and the second facing member 3C along the directions indicated by the arrows Pa and Pb. A magnetic path is formed inside. This magnetic path has a minute gap 61 between the surface 2b of the disk 2B and the facing surface 36 of the first facing member 3B, or a predetermined gap between the back surface 2a of the disk 2B and the facing surfaces 37A and 37B of the second facing member 3C. It penetrates through the magnetorheological fluid 6 filled in. As a result, the viscosity (shear stress) corresponding to the strength of the magnetic field appears in the magnetorheological fluid 6, and the transmission torque between the disc 2B and the two facing members 3B and 3C becomes the strength of the magnetic field. Increases accordingly.

  According to the rotary braking device 100B according to the third embodiment described above, as in the rotary braking devices 100 and 100A according to the first and second embodiments, the minute gap 61 filled with the magnetorheological fluid 6 is used. Is determined by the amount of protrusion of the sphere 8 from the surface 2b of the disk 2B. Therefore, the diameter accuracy of the sphere 8, the shape accuracy of the recess 22 (for example, depth dimensional accuracy), and the disk 2B Only by increasing the squareness accuracy between the surface 2b and the axis N to some extent, the minute gap 61 of 0.1 mm or less can be formed. And since the location which should raise a dimensional accuracy in order to make the clearance gap between the disk 2B and the opposing surface 36 into a micro clearance gap of 0.1 mm or less reduces a processing cost. The predetermined gap between the back surface 2a of the disc 2B and the facing surfaces 37A and 37B of the second facing member 3C cannot be easily reduced (similar to the conventional art), but in this embodiment, the disc 2B Since it is possible to apply a magnetic field to the magnetorheological fluid 6 on both sides, it is easy to improve the transmission torque as compared with the rotary braking device 100 according to the first embodiment.

  Further, according to the rotary braking device 100B according to the third embodiment, since the through hole 25 is formed in the disc 2B, the magnetic path described above can be reliably formed. That is, when this through-hole 25 is not formed, a magnetic path as shown by an arrow P in FIG. 4 is formed, and the magnetic field 61 filled in the minute gap 61 between the disk 2B and the facing member 3B. Although the viscous fluid 6 cannot penetrate the magnetic path, in the present embodiment, such a disadvantage does not occur because the through hole 25 is formed in the disk 2B.

  The present invention is applicable to a rotary braking device that changes the torque transmitted between the input side and the output side via the magnetorheological fluid by changing the strength of the magnetic field applied to the magnetorheological fluid.

1, 1B Rotating shaft 2, 2A, 2B Disc 2a One surface 2b The other surface 3, 3A Face-to-face member 3B First face-to-face member 3C Second face-to-face member (yoke)
4 Coil 6 Magnetorheological fluid 8 Sphere 22 Recessed portion 25 Through-hole 31A, 31B, 36, 37A, 37B Opposing surface 61 Minute gap

Claims (3)

A rotation axis;
A disc made of a magnetic material connected to an end of the rotating shaft at the center of one surface;
A facing member made of a magnetic material having opposing surfaces facing in parallel with respect to the other surface of the disk via a minute gap,
A coil disposed concentrically around the axis of the rotating shaft so that a magnetic path passing through the minute gap is formed when a current is applied;
A magnetorheological fluid filled in the minute gap;
A rotary braking device comprising:
A recess is formed in which a spherical body made of a non-magnetic material for preventing interference of the magnetic path is formed at the center of the other surface of the disk,
The sphere is fitted to the concave portion to the deepest position, and a part of the sphere protrudes from the other surface of the disk by a predetermined amount in the axial direction and comes into contact with the opposing surface, thereby forming the minute gap. A rotary braking device characterized by being formed. The rotary braking device according to claim 1,
The coil is disposed on one surface side of the disc,
Surrounding the inner peripheral side, outer peripheral side, and anti-disc side of the coil, and applying current to the coil to both ends that become magnetic poles, on the inner peripheral side and outer peripheral side of one surface of the disc A rotary braking device in which yokes each having opposing surfaces are provided. The rotary braking device according to claim 2,
The rotary braking device according to claim 1, wherein a plurality of through-holes penetrating in the plate thickness direction are formed in the disc in the same radial range as the radius range in which the coil is disposed.

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