JP2008202744A - Rotary damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary damper capable of being compatible with a larger attenuation force of the rotary damper and a miniaturization. <P>SOLUTION: The rotary damper R1 comprises a hollow case 1, a shaft 2 passed through freely rotatably inside the case 1, at least one or more plates 3 connected in one end of the shaft 2 to be accommodated in the case 1, and a coil 4 arranged in the outer peripheral side of the other end of the shaft 2 and a magnetic viscous fluid is filled into the case 2 inside so that a magnetic operation area can be larger and a larger damping force can be generated and the rotary damper R1 can be miniaturized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotary damper using a magnetorheological fluid.

  In a rotary damper using this kind of magnetorheological fluid, for example, as shown in FIG. 5, an annular core 40 having an annular groove 41 formed on the outer peripheral side, and a coil 42 wound in the annular groove 41, A flywheel 46 including a stator S composed of the shaft S, a shaft 45 rotatably inserted into the stator S via ball bearings 43, 44, and a cylindrical portion 47 connected to the shaft 45 and facing the outer periphery of the stator S. And a seal 48 that seals between the open end of the cylindrical portion 47 of the flywheel 46 and the stator S, and a gap between the flywheel 46 and the stator S is filled with a magnetorheological fluid. Is known (for example, see Patent Document 1).

In this rotary damper, when the stator S is on the fixed side, the flywheel 46 rotates together with the shaft 45. The stator S and the cylindrical portion 47 of the flywheel 46 form a magnetic path through two gaps between the upper and lower sides and the cylindrical portion 47 with the annular groove 41 on the outer periphery of the stator S as a boundary. The coil is excited to increase the viscosity of the magnetorheological fluid in the gap, thereby providing resistance to the rotational motion of the flywheel 46 relative to the stator S and generating a damping force.
US Patent Publication US6186290B1 (FIG. 1)

  However, in the rotary damper described above, the magnetic path is composed of the stator S and the cylindrical portion 47 opposed to the outer periphery of the stator S as described above, so that the area for applying magnetism to the magnetorheological fluid is small, and the damping is large. It is hard to get power. Therefore, it is difficult to achieve both the generation of a large damping force and the downsizing of the rotary damper.

  Therefore, the present invention has been developed to improve the above-described problems, and it is an object of the present invention to provide a rotary damper capable of achieving both generation of a large damping force and miniaturization.

  In order to achieve the above-described object, the rotary damper of the present invention includes a hollow case, a shaft that is rotatably inserted into the case, and at least one piece that is housed in the case and connected to one end of the shaft. The above plate and a coil disposed on the outer peripheral side of the other end of the shaft are provided, and the case is filled with a magnetorheological fluid.

  According to the rotary damper of the present invention, the area on which the magnetic field acts can be dramatically increased as compared with the conventional rotary damper, so that a large damping force can be generated. In addition, since a large damping force can be generated, less power is consumed to generate the same level of damping force as that of a conventional rotary damper, thus saving power and further reducing the size of the rotary damper. It becomes possible.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a perspective sectional view of a rotary damper according to an embodiment. FIG. 2 is a diagram illustrating the magnetic path of the rotary damper according to the embodiment. FIG. 3 is a cross-sectional view of a rotary damper according to a modification of the embodiment. FIG. 4 is a perspective sectional view of a rotary damper according to another embodiment.

  As shown in FIG. 1, the rotary damper R <b> 1 in one embodiment includes a hollow case 1, a shaft 2 that is rotatably inserted into the case 1, and a housing 1 that is accommodated in one end of the shaft 2. A plurality of plates 3 to be connected, a coil 4 disposed on the outer peripheral side of the other end of the shaft 2, and a permanent magnet 5 disposed in series with the coil on the outer periphery of the other end of the shaft 2. The case 1 is filled with a magnetorheological fluid.

  Hereinafter, each part will be described in detail. The case 1 includes an annular case-side plate 11 and an inner periphery which is alternately stacked on the case-side plate 11 so as to face the outer periphery of the plate 3 and sandwich the case-side plate 11 from above and below. An annular spacer 12, an upper lid 13 laminated on the uppermost spacer 12, and a lower lid 14 laminated on the lowermost spacer 12 are configured.

  The case side plate 11 has the same outer diameter as that of the spacer 12, and the inner diameter is set to a diameter that allows the shaft 2 to be inserted, and is smaller than the spacer 12. On the other hand, the inner diameter of the spacer 12 is set to a diameter that does not interfere with the rotation of the plate 3 to be described later in the case 1.

  In this embodiment, the spacers 12 are always laminated on the upper and lower sides of the case side plate 11 in FIG. 1, and in this case, between the two case side plates 11 and the uppermost stage. Spacers 12 are respectively provided above the case side plate 11 and below the lowermost case side plate 11.

  Further, an annular upper lid 13 is laminated above the spacer 12 arranged at the uppermost stage in FIG. 1, and the outer diameter of the upper lid 13 is the outer diameter of the case side plate 11 and the spacer 12 described above. A bearing 15 made of a non-magnetic material is fixed to the inner periphery thereof, and a seal 16 slidably contacting the outer periphery of the shaft 2 is provided in an annular groove provided on the inner periphery of the bearing 15. ing.

  The lower lid 14 includes an annular plate portion 14a stacked below the lowermost spacer 12, and a bottomed cylindrical tube portion 14b suspended from the inner peripheral edge of the annular plate portion 14a. A hole 14c into which the shaft 2 is inserted is provided at the bottom of the portion 14b, and a seal 17 that is in sliding contact with the outer periphery of the shaft 2 is provided in an annular groove provided in the inner wall of the hole 14c. Furthermore, the coil 4 wound around the coil bobbin 6 and the annular permanent magnet 5 disposed above the coil 4 are both fixed and accommodated in the cylindrical portion 14b.

  Further, the cylindrical portion 14b is provided with a lead wire insertion hole 14d, and the coil 4 is connected to an external power source via a lead wire 4a inserted into the lead wire insertion hole 14d. It can be applied.

  Each member of the case side plate 11, the spacer 12, the upper lid 13 and the lower lid 14 constituting the case 1 is fixed by bolts and nuts, for example, although not shown. Since the case 1 is filled with the magnetorheological fluid, O in the contact portions of the case side plate 11, the spacer 12, the upper lid 13, and the lower lid 14 in order to prevent leakage of the magnetorheological fluid. A seal such as a ring may be provided. A seal 18 is provided to prevent leakage of the magnetorheological fluid from between the lead wire 4a and the lead wire insertion hole 14d.

  Subsequently, a shaft 2 is inserted in the center of the case 1 configured as described above, and one end of the shaft 2 on the upper end side in FIG. 1 is slidable on the inner periphery of the upper lid 13 of the case 1. The other end of the shaft 2, which is the lower end side in FIG. 1, is pivotally supported by the hole 14 c of the lower lid 14 of the case 1 so as to be rotatable with respect to the case 1.

  The shaft 2 and the case 1 are sealed with seals 16 and 17, and the inside of the case 1 is sealed.

  Further, the shaft 2 includes a step portion 2a on the way, a small diameter portion 2b on one end side with the step portion 2a as a boundary, a large diameter portion 2c on the other end side, and an annular shape on the small diameter portion 2b. A plurality of plates 3 and spacers 7 are stacked alternately and fixed by a non-magnetic nut 8 that is screwed onto the small diameter portion 2 b of the shaft 2.

  As shown in the figure, the plate 3 has an annular shape and is fixed to the shaft 2, and a spacer 7 is interposed between the plates 3 so that the outer periphery thereof faces the inner periphery of the spacer 12 of the case 1. Are arranged between the upper lid 13 and the case side plate 11, between the case side plates 11, and between the case side plate 11 and the annular plate portion 14 a of the lower lid 14, respectively. Yes. The gap of the thus configured rotary damper R1 is filled with a magnetorheological fluid.

  Further, a stop ring 9 that is in contact with the upper surface of the upper lid 13 is mounted on the outer periphery of one end that is the upper end of the shaft 2, and is in contact with the lower surface of the bottom portion of the cylindrical portion 14 b of the lower lid 14 on the outer periphery of the other end that is the lower end of the shaft 2. A stop ring 10 is mounted, and the stop rings 9 and 10 prevent the shaft 2 from dropping from the case 1.

  When the shaft 2 and the plate 3 are assembled to the case 1, for example, the shaft 2 is inserted into the lower cover 14 of the case 1 to which the coil 4 and the permanent magnet 5 are already attached, and the spacer 12 on the case 1 side is attached to the lower cover. 14 and the plate 3 on the step 2 a of the shaft 2, the case side plate 11 is stacked on the spacer 12 of the case 1, and the spacer 7 is stacked on the plate 3. Then, by repeating the procedure of alternately laminating, injecting the magnetorheological fluid and finally laminating the upper lid 13, the rotary damper R1 can be assembled, and the assembling process is also simple.

  The rotary damper R1 in the embodiment is configured as described above, and in this rotary damper R1, the parts of the case 1, the shaft 2, and the plate 3 are all formed of a magnetic material, and as shown in FIG. , Plate 3, case side plate 11, spacer 12, upper lid 13 and lower lid 14 constitute a magnetic path M, and gap a between upper lid 13 and plate 3 and gap between case side plate 11 and plate 3. b and the magnetic field generated in the gaps a, b, c of the gap c between the annular plate portion 14a of the lower lid 14 and the plate 3 increase the viscosity of the magnetorheological fluid existing in the gaps a, b, c. It is like that.

  Therefore, in this rotary damper R1, the area where the magnetic field acts is remarkably larger than that of the conventional rotary damper in which the magnetic field is applied only to the gap between the cylindrical portion 47 of the flywheel 46 and the outer periphery of the stator S. Therefore, a large damping force can be generated. In addition, since a large damping force can be generated, power consumption can be reduced because less power is consumed to generate the same level of damping force as a conventional rotary damper, and further, the rotary damper R1 can be reduced in size. Is possible.

  In this embodiment, a layout in which the coil 4 is arranged on the outer periphery of the shaft 2 is adopted, and the magnetic path M is configured by the plate 3 and the case side plate 11 not including the coil 4 built-in. Since the area is secured, the plate 3 and the case side plate 11 can be made thin, and the rotary damper R1 is not increased in size in the axial direction. Since a sandwich structure in which a plurality of plates 11 are arranged alternately is adopted, the magnetic field action area can be increased dramatically, and particularly suitable for generating a large damping force.

  Further, since the layout in which the coil 4 is arranged on the outer periphery of the shaft 2 is adopted, for example, as shown in FIG. 3, the coil 4 accommodated in the cylindrical portion 14 a of the lower lid 14 is arranged at the upper side in FIG. 1. The seal 19 can be provided, the situation where the coil 4 is immersed in the magnetorheological fluid can be prevented, and the protection of the coil 4 can be ensured. In this case, it is not necessary to provide a seal that is in sliding contact with the outer periphery of the shaft 2 on the inner wall of the hole 14c.

  Next, the operation of the rotary damper R1 will be described. In this embodiment, when the coil 4 is not excited, a magnetic field acts on the gaps a, b, and c by the permanent magnet 5 so that a damping force can be generated even when no current is applied. It has become.

  When the coil 4 is excited so as to generate a magnetic flux in the same direction as the magnetic flux generated by the permanent magnet 5, the magnetic flux in the magnetic path M is increased to generate a larger damping force in the rotary damper R1. Can be made. Further, in this case, the magnetic flux in the gaps a, b, and c can be changed by changing the amount of current supplied to the coil 4, so that the damping force can be changed.

  Further, when the coil 4 is excited so as to generate a magnetic flux in a direction that cancels the magnetic flux generated by the permanent magnet 5, it is possible to reduce the generated damping force of the rotary damper R1 by reducing the magnetic flux in the magnetic path M. it can. Also in this case, since the magnetic flux in the gaps a, b, and c can be changed by changing the amount of current supplied to the coil 4, it is possible to change the damping force.

  Therefore, the rotary damper R1 can be greatly changed from the state in which almost no damping force is generated to the state in which a large damping force is generated by canceling out the magnetic flux of the permanent magnet 5 by the excitation of the coil 4.

  Further, when the coil 4 is not energized, the rotary damper R1 can generate a damping force by the action of the permanent magnet 5, so that even if the excitation of the coil 4 becomes impossible, A state where no damping force can be generated can be avoided, and fail-safe is realized.

  The magnetorheological fluid is a slurry in which ferromagnetic particles are dispersed at a high concentration in a dispersion medium such as silicone oil. In the conventional rotary damper, if the rotary damper is not driven for a long time, the above ferromagnetic substance In the rotary damper R1 in the present embodiment, there is a risk that particles will settle, but even when the coil 4 is not energized, there is a magnetic field generated by the permanent magnet 5 in the gaps a, b, and c. In order to act, clusters of ferromagnetic particles (bridges) between the upper lid 13 and the plate 3, between the case side plate 11 and the plate 3, and between the annular plate portion 14 a of the lower lid 14 and the plate 3. Structure), the ferromagnetic particles can be held in the gaps a, b, and c to prevent precipitation. Therefore, even when the rotary damper R1 is driven after being stationary for a long period of time, a predetermined damping force can be exerted from the initial driving stage.

  The plate 3, the upper lid 13, the case-side plate 11, and the lower lid 14 have an annular plate portion 14 a in the form of a flat plate, but the surface facing the gaps a, b, and c is uneven. Also good.

  Next, a rotary damper R2 in another embodiment will be described. In the rotary damper R2 in the other embodiment, the coil 4 and the permanent magnet 5 are not housed in the case 20 but are attached to the outside of the case 20 as described above. And different. The other configuration is the same as that of the rotary damper R1 of the embodiment, and different points will be described below. The same members are denoted by the same reference numerals and description thereof will be omitted.

  In the rotary damper R2 in the other embodiment, as shown in FIG. 4, the case 20 includes the upper lid 21, the case side plate 22, and the spacer 23 as in the embodiment. The shape is different from the lower lid 14 in the case 1 of the embodiment. A bearing 15 is provided on the inner periphery of the upper lid 21 as in the embodiment.

  The lower lid 24 has a simple annular plate shape and is provided with an annular seal 25 in sliding contact with the outer periphery of the shaft 2 on the inner peripheral side. The other end of the shaft 2 on the lower end side in FIG. The stop ring 10 that protrudes largely outward from the shaft and prevents the shaft 2 from coming off comes into contact with the lower surface of the lower lid 24. Thus, in other embodiments, the case 20 filled with the magnetorheological fluid does not contain the coil 4 and the permanent magnet 5.

  And the coil case 26 which accommodated the coil 4 and the permanent magnet 5 arrange | positioned in series inside is mounted | worn with the lower end side of the case 20 in which the shaft 2 comprised in this way was integrated.

  The coil case 26 is formed of a magnetic material, and includes a bottom portion 26a through which the other end of the shaft 2 is inserted, a cylindrical portion 26b that rises from the outer periphery of the bottom portion 26a, and a flange 26c that is continuous with the outer periphery of the upper end of the cylindrical portion 26b. The flange 26c is laminated on the lower surface of the lower lid 24 and fixed to the case 20 by screw fastening or the like. In addition, the coil 4 and the permanent magnet 5 are housed in series in the cylindrical portion 26b. When the coil case 26 is fixed to the case 20 as described above, the coil 4 and the permanent magnet 5 are permanently attached to the outer periphery of the other end of the shaft 2. The magnet 5 is arranged in series.

  In other embodiments as well, a lead wire insertion hole 26d through which the lead wire 4a can be inserted is provided in the cylindrical portion 26b so that current can be supplied to the coil 4 from an external power supply.

  In the rotary damper R2 configured as described above, the magnetic path is configured by the members of the shaft 2, the plate 3, the case side plate 22, the spacer 23, the upper lid 21 and the lower lid 24, and the coil case 26. Therefore, the configuration of the magnetic path is substantially the same as that in the embodiment, and the magnetic field action area is dramatically increased as in the embodiment, so that a large damping force can be generated. In addition, since a large damping force can be generated, power consumption is reduced because less power is consumed to generate a damping force comparable to that of the conventional rotary damper, and further, the rotary damper R2 can be reduced in size. In addition, it is possible to achieve the same operational effects as the rotary damper R1 of the above-described embodiment.

  In addition, in this embodiment, since the coil 4 is accommodated in the coil case 26 attached to the case 20 and is disposed outside the case 20 filled with the magnetorheological fluid, the coil 4 is disposed on the magnetorheological fluid. As a result, the case 20, the shaft 2 and the plate 3 can be assembled and the coil 4 and the coil case 26 can be assembled. In addition, the function of the rotary damper R2 can be restored by replacing only the defective assembly when either the coil 4 side assembly or the case 20 side assembly fails. In addition, the replacement is easy and the practicality is improved.

  In the case of each of the embodiments described above, the case-side plates 11 and 22, the plate 3, the spacers 12 and 23, the upper lids 13 and 21, and the lower lids 14 and 24 have a circular outer shape. Although the working area can be increased as compared with other shapes, the effect of the present invention is not lost even if the shape is other than circular. Further, although the coil 4 is arranged on the lower side in the figure and the permanent magnet 5 is arranged on the upper side in the figure, they may be arranged in reverse.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a perspective sectional view of the rotary damper in one embodiment. It is a figure explaining the magnetic path of the rotary damper in one embodiment. It is a perspective sectional view of a rotary damper in one modification of an embodiment. It is a perspective sectional view of a rotary damper in other embodiments. It is sectional drawing of the conventional rotary damper.

Explanation of symbols

1, 20 Case 2 Shaft 2a Stepped portion 2b Small diameter portion 2c Large diameter portion 3 Plate 4 Coil 4a Lead wire 5 Permanent magnet 6 Coil bobbin 7 Spacer 8 Nut 9, 10 Stop ring 11, 22 Case side plate 12, 23 in case Spacers 13, 21 Upper lid 14 in case 24 Lower lid 15 in case Bearing 16, 17, 18, 19, 25 Seal 14a Annular plate 14b in lower lid Tube portion 14c in lower lid 14d hole in lower lid 14d Lead wire in lower lid Insertion hole 26 Coil case 26a Bottom portion 26b in coil case Tube portion 26c in coil case Flange 26d in coil case Lead wire insertion holes a, b, c in coil case M Magnetic path R1, R2 Rotary damper

Claims (5)

A hollow case, a shaft rotatably inserted into the case, at least one plate housed in the case and connected to one end of the shaft, and disposed on the outer peripheral side of the other end of the shaft A rotary damper comprising a coil and filled with a magnetorheological fluid in a case. The rotary damper according to claim 1, wherein the other end of the shaft is protruded outside the case, and a coil is disposed on the outer periphery of the other end of the protruding shaft. The rotary damper according to claim 1 or 2, wherein a plurality of plates are connected to a shaft, and a case side plate that is connected to the case side and allows insertion of the shaft is disposed between the plates. The case includes an annular case side plate, an annular spacer that is alternately stacked on the case side plate with the inner periphery facing the outer periphery of the plate, and an upper lid that is stacked on the uppermost spacer. A rotary damper according to any one of claims 1 to 3, further comprising a lower lid laminated on the lowermost spacer. The rotary damper according to any one of claims 1 to 4, wherein a permanent magnet is provided in series with the coil on the outer periphery of the other end of the shaft.

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