JP2018189110A - Rotary damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary damper capable of improving attenuation force of a rotary damper.SOLUTION: A rotary damper comprises: a relatively rotatable case 3; a rotor 5 stored in the case 3; an attenuation force generation part 7 where functional fluid F is interposed, the functional fluid generating attenuation force by making a magnetic flux M pass through an interval D between the case 3 and the rotor 5; a permanent magnet 9 configured to generate the magnetic flux M over the attenuation force generation part 7; and a recess part 21 provided in the rotor 5, partially enlarging the interval D in the attenuation force generation part 7, and holding the functional fluid F.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a rotary damper that generates a damping force using a functional fluid such as a magnetic fluid or a magnetorheological fluid.

  As a conventional rotary damper, for example, as in Patent Document 1, there is one in which a magnetorheological fluid is sealed in a case having a cylindrical hole-shaped storage chamber and a cylindrical rotary body is stored in a relatively rotatable manner.

  In this rotary damper, a permanent magnet is held on a rotary body or a case, and projecting teeth are provided on the rotary body in order to concentrate the magnetic flux.

  Accordingly, in the conventional rotary damper, the magnetic viscous fluid generates a shearing resistance and obtains a damping force by passing between the case and the rotating body while the magnetic flux is concentrated through the teeth of the rotating body. Yes.

  However, in such a configuration, a shear resistance is generated only at the teeth of the rotating body, so that there is a limit in obtaining a damping force. Such a problem is not limited to a permanent magnet, but also occurs when an electromagnet is used.

JP 2005-164013 A

  The problem to be solved is that there is a limit to obtaining the damping force.

  In order to improve the damping force of the rotary damper, the present invention provides a relatively rotatable case, a rotating body accommodated in the case, and the magnetic flux passing through a gap between the case and the rotating body. A damping force generating part interposing a functional fluid that generates a damping force in the gap, a magnet for generating the magnetic flux across the damping force generating part, and one or both of the case and the rotating body are provided. The main feature of the rotary damper is that it includes a recess for partially expanding the gap in the damping force generating portion to hold the functional fluid.

  The rotary damper of the present invention can improve the damping force by increasing the range occupied by the damping force generating portion, and even if the gap between the case and the rotating body is reduced, one of the case and the rotating body or By holding the functional fluid with the concave portions provided on both sides, it is possible to reliably generate a damping force.

(Example 1) which is a top view of a rotation damper. FIG. 2 is a sectional view taken along line II-II in FIG. 1 (Example 1). FIG. 3 is a sectional view taken along line III-III in FIG. 2 (Example 1). FIG. 3 is an enlarged sectional view of a main part of FIG. 2 (Example 1). It is sectional drawing which shows notionally the functional fluid at the time of damping force generation | occurrence | production (Example 1). (Example 2) which is sectional drawing of a rotation damper. It is a graph which shows the load torque of Example 1 and Example 2 (Examples 1, 2). (Example 3) which is sectional drawing of a rotation damper. FIG. 9 is an enlarged cross-sectional view of a main part of FIG. 8 (Example 3). (Example 3) which is sectional drawing of a rotation damper. (Example 4) which is sectional drawing of a rotation damper.

  The purpose of improving the damping force of the rotary damper is to reduce the damping force generating part in which the functional fluid is interposed in the gap between the case and the rotating body. This was realized by partially providing a recess that widens the gap.

  In other words, the rotary damper is a damping that includes a relatively rotatable case, a rotating body housed in the case, and a functional fluid that generates a damping force when magnetic flux passes through a gap between the case and the rotating body. A force generator, a magnet that generates magnetic flux across the damping force generator, and a recess that is provided in one or both of the case and the rotating body and that partially expands the gap in the damping force generator to hold the functional fluid. Is provided.

  The magnet may be a permanent magnet or an electromagnet.

  You may provide a recessed part in either one or both of the surfaces which oppose in the 1st direction along the rotation radius of relative rotation of a case and a rotary body. Moreover, you may provide a recessed part in the any one or both of the surface which opposes in the 2nd direction along the rotation axis of the relative rotation of a case and a rotary body.

  In the case of being provided on the surface facing in the first direction, the concave portion is provided on one or both of the surfaces facing in the first direction along the rotation radius of the relative rotation of the case and the rotating body, and between the case and the rotating body. It is good also as a structure which reaches the clearance gap in the 2nd direction along the rotation axis of relative rotation.

  Furthermore, you may set a recessed part within the range which faced the area | region of the clearance gap where the magnetic flux of a magnet passes in the 2nd direction.

  Moreover, when providing in the surface which opposes in a 1st direction, a rotary body is cylindrical shape, a case has a cylindrical hole-shaped storage chamber which fits a rotary body rotatably, and a recessed part is a storage chamber of a case. It is good also as a structure provided with two or more by the circumferential direction predetermined space | interval with respect to the outer peripheral surface of the rotary body which opposes an inner peripheral surface in a 1st direction.

  Moreover, when providing in the surface which opposes in a 1st direction, a rotating body has a flat surface in the outer peripheral part located in the other side in a 1st direction with respect to a columnar base shape, respectively, and a case can rotate a rotating body freely It is good also as a structure which has a cylindrical hole-shaped storage chamber fitted to, and a recessed part is an arcuate part divided between the flat surface and the inner peripheral surface of the storage chamber of a case in a 1st direction.

[Structure of rotating damper]
1 is a plan view of a rotary damper according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4 and 4 are enlarged cross-sectional views of the main part of FIG. In the following, the “radial direction” means a direction along the rotation radius of the relative rotation between the case 3 and the rotating body 5 of the rotary damper 1 as the first direction, and the “axial direction” means It means the direction along the rotational axis of relative rotation between the case 3 and the rotating body 5 as the second direction.

  The rotary damper 1 of the present embodiment generates, for example, a damping force for the movable side such as a sliding door (not shown) by the functional fluid F. As shown in FIGS. 1 to 4, the case 3, the rotating body 5, A damping force generator 7 and a permanent magnet 9 are provided.

  The case 3 is made of a non-magnetic material and is made of, for example, a resin. As the nonmagnetic material, for example, a nonmagnetic metal other than resin, ceramic, or the like can be used. Examples of the nonmagnetic metal include copper, aluminum, and stainless steel.

  The case 3 includes a cylindrical case body 11. The case body 11 has a shape in which one side in the axial direction (bottom side in FIG. 2) is closed by an integrated bottom plate 13 and the other side in the axial direction (upper side in FIG. 2) opens. The opening of the case body 11 is closed by the lid 15 being integrally attached by adhesion, welding or the like. A through hole 15 a is formed in the axial center portion of the lid portion 15.

  A cylindrical hole-shaped storage chamber 17 is defined on the inner periphery of the case body 11. A shaft portion 13 a protrudes from the shaft center portion of the bottom plate 13 in the storage chamber 17. A flange portion 19 is integrally provided on the outer periphery of the case body 11. The rotary damper 1 is fixed to the fixed side or the like via the flange portion 19.

  The rotating body 5 is made of a magnetic material or a nonmagnetic material. The rotating body 5 of the present embodiment has a columnar basic shape. In addition, a basic shape means the shape used as the foundation of the rotary body 5 on having the recessed part 21 mentioned later.

  The rotating body 5 is disposed in the housing chamber 17 of the case body 11 of the case 3 so as to be relatively rotatable, and has an outer shape slightly smaller than the housing chamber 17 of the case 3. Thereby, a gap D is secured between the rotating body 5 and the case 3. The functional fluid F is interposed in the gap D to constitute the damping force generator 7. In the present embodiment, the gap D includes both the radial gap D1 and the axial gap D2 (FIG. 4).

  A fitting hole 5 a is formed in the shaft center portion of the rotating body 5 corresponding to the shaft 13 a of the case 3. Therefore, the rotating body 5 is rotatably fitted to the shaft 13a of the case 3 in the fitting hole 5a. A rotating shaft 5 b that rotates integrally with the rotating body 5 protrudes from the axial center of the rotating body 5.

  The rotating shaft 5 b protrudes from the case 3 through the through hole 15 a of the lid portion 15. The seal member 15b is in close contact with the rotating shaft 5 in the through hole 15a. For example, an O-ring or an X-ring is used for the seal member 15b. Although not shown, torque is input to the outer end of the rotating shaft 5b from the movable side via a gear or the like.

  A concave portion 21 is provided on the outer peripheral portion of the rotating body 5.

  The recess 21 is provided in one or both of the case 3 and the rotating body 5, and in the damping force generation unit 7, the gap D between the case 3 and the rotating body 5 is partially widened to bring the functional fluid F into the interior. It is to hold.

  In the present embodiment, the concave portion 21 is provided only in the rotating body 5. Further, in this embodiment, since the functional fluid F is interposed in the entire gap D between the case 3 and the rotating body 5 to form the damping force generating unit 7, the entire area between the case 3 and the rotating body 5 is formed. Thus, a recess 21 is formed.

  Specifically, a plurality of recesses 21 are formed in the circumferential direction with respect to the outer peripheral surface 5c of the rotating body 5 out of the inner peripheral surface 17a of the housing chamber 17 of the case 3 and the outer peripheral surface 5c of the rotating body 5 that face each other in the radial direction. It is provided at predetermined intervals.

  The interval between the recesses 21 is, for example, every 60 degrees in the circumferential direction. However, the interval between the recesses 21 and the number of the recesses 21 associated therewith are not particularly limited, and can be increased or decreased according to required characteristics. The recesses 21 do not necessarily have to be provided at every predetermined interval, and can be arranged with the intervals between the recesses 21 varied or arranged in a biased manner in the circumferential direction.

  Each recessed part 21 is provided along the radial direction from the outer peripheral surface 5c of the rotating body 5 inward as shown in the cross section of FIG. 3, and opens on the outer peripheral surface 5c of the rotating body 5. As a result, the recess 21 communicates with the radial gap D1.

  The bottom (inside) of the recess 21 in FIG. 3 is curved. The length in the radial direction of the recess 21 may be set within a range through which a magnetic flux M described later passes, for example, a range facing the outer peripheral portion D2a of the gap D2 in the axial direction, as shown in FIG.

  Moreover, the recessed part 21 is extended over the both end surfaces 5d and 5e of the axial direction of the rotary body 5 like the longitudinal cross-section of FIG. However, it is also possible to provide from one end face 5d in the axial direction of the rotating body 5 to an intermediate portion in the axial direction. In any case, the concave portion 21 reaches the gap D2 in the axial direction between the opposing case 3 and the rotating body 5, as shown in FIG.

  As described above, the damping force generation unit 7 is configured by interposing the functional fluid F that generates the damping force when the magnetic flux M passes through the gap D between the relatively rotatable case 3 and the rotating body 5. is there.

  As the functional fluid F, a magnetic fluid in which iron powder or the like is dispersed or a magnetorheological fluid called MR fluid is used. The functional fluid F forms a cluster (also referred to as a spike) C of iron powder or the like when the magnetic flux M passes between the case 3 and the rotating body 5, and is attenuated by shear resistance between the case 3 and the rotating body 5. Generate power. FIG. 5 conceptually shows the functional fluid F when the damping force is generated in the gap D2 in the axial direction.

  The permanent magnet 9 is made of an alnico magnet, a ferrite magnet, a neodymium magnet, or the like. The permanent magnet 9 of the present embodiment is formed in a plate shape as shown in FIG. 2 and is fixed to the bottom plate 13 of the case 3 outside the case 3. The permanent magnet 9 has magnetic poles with different front and back surfaces, and the magnetic flux M from the front surface side passes through the rotator 5 to the back surface side in a loop shape in the radially outer peripheral portion.

[Rotation damper operation]
The rotary damper 1 is used with a rotating shaft 5b coupled to a movable side such as a sliding door and the case 3 fixed to a fixed side.

  When torque is input to the rotating shaft 5b from the movable side, the rotating body 5 is rotated relative to the case 3 via the rotating shaft 5b. This relative rotation is attenuated by the damping force generator 7.

  That is, in the damping force generating unit 7, the magnetic fluid M from the permanent magnet 9 passes, so that the functional fluid F forms a cluster C of fine particles such as iron powder as shown in FIG. Since the rotating body 5 rotates relative to the case 3 in this state, the relative rotation of the rotating body 5 is attenuated by the shear resistance due to the cluster C.

  At this time, in order to effectively generate a damping force, it is necessary to spread the functional fluid F in the gap D. However, if the range of the damping force generation unit 7 is enlarged and provided across the entire space between the case 3 and the rotating body 5, the gap D becomes fine accordingly, so that the functional fluid F spreads. It will be difficult.

  On the other hand, in the present embodiment, since the concave portion 21 is provided on the outer peripheral surface 5 c of the rotating body 5, the functional fluid F held in the concave portion 21 is at least in the concave portion 21 with the rotation of the rotating body 5. Can be spread over the outer peripheral portion D2a of the axial gap D2 and the entire radial gap D1.

  Since the damping force is mainly generated at the outer peripheral portion D2a through which the magnetic flux M in the axial gap D2 passes, the damping force can be effectively generated in the rotary damper 1 of the present embodiment. Further, in the rotary damper 1 of the present embodiment, since the recesses 21 are formed at predetermined intervals, the functional fluid F can be distributed more effectively and evenly in the gap D, and more effectively attenuated. Force can be generated.

[Effect of Example 1]
As described above, in the rotary damper 1 of this embodiment, the magnetic flux M passes through the relatively rotatable case 3 and the rotating body 5 accommodated in the case 3 and the gap D between the case 3 and the rotating body 5. And a permanent magnet 9 for generating a magnetic flux M across the damping force generator 7 and a rotating body 5 (case 3 and rotating body). 5) and a recess 21 for holding the functional fluid F by partially expanding the gap D in the damping force generator 7.

  Therefore, in the present embodiment, the damping force can be improved by increasing the range occupied by the damping force generating portion 7 as compared with the conventional case, so that even if the gap between the case 3 and the rotating body 5 is reduced, the concave portion is reduced. Since 21 holds the functional fluid F, the functional fluid F can be spread over the gap D, and a damping force can be reliably generated.

  Further, the recess 21 is provided on the outer peripheral surface 5c of the rotating body 5 facing the inner peripheral surface 17a of the housing chamber 17 of the case 3 in the radial direction, and a gap between the case 3 and the rotating body 5 facing in the axial direction. D2 is reached. For this reason, in the present embodiment, the functional fluid F can be reliably distributed to the outer peripheral portion D2a in the axial gap D2 in which mainly the damping force is generated, and the damping force can be effectively generated. It becomes possible.

  Since the concave portion 21 is set within the range of the rotating body 5 facing the outer peripheral portion D2a of the axial gap D2 through which the looping magnetic flux M passes, functionality is surely ensured in the outer peripheral portion D2a of the axial gap D2. It is possible to spread the fluid F and generate the damping force more reliably.

  In the present embodiment, the rotating body 5 has a columnar shape, the case 3 has a cylindrical hole-shaped storage chamber 17 into which the rotating body 5 is rotatably fitted, and the recess 21 is an inner periphery of the storage chamber 17 of the case 3. A plurality of outer peripheral surfaces 5c of the rotating body 5 that are opposed to the surface 17a in the radial direction are provided at predetermined intervals in the circumferential direction.

  Therefore, in this embodiment, the functional fluid F can be spread more effectively and evenly in the gap D, and a damping force can be generated more reliably.

  Note that, instead of providing the recess 21 on the outer peripheral surface 5c of the rotating body 5, even if a recess is provided on the inner peripheral surface 17a of the housing chamber 17 of the case 3, the functional fluid F is reliably distributed in the radial gap D1. Therefore, it is possible to generate a damping force effectively, although not as much as when it is provided on the rotating body 5 side.

  FIG. 6 is a cross-sectional view of the rotary damper according to the second embodiment. 6 corresponds to a cross section taken along line III-III in FIG. Moreover, in Example 2, the same code | symbol is attached | subjected to the component corresponding to Example 1, and the overlapping description is abbreviate | omitted.

  The rotary damper 1 of the present embodiment is obtained by changing the shape of the rotating body 5.

  That is, the rotating body 5 has a shape having flat surfaces 23 at outer peripheral portions located on opposite sides in the radial direction with respect to the columnar basic shape. Here, the basic shape means a shape that is the basis of the rotating body 5 having the flat surface 23.

  The concave portion 21 is an arcuate portion that is partitioned between the flat surface 23 and the inner peripheral surface 17a of the housing chamber 17 of the case 3 in the radial direction. The radial height H of the recess 21 is set within the range of the rotating body 5 facing the outer peripheral portion D2a of the axial gap D2 through which the looping magnetic flux M passes (see FIG. 4).

  In the second embodiment, the same effects as those in the first embodiment can be achieved.

  FIG. 7 is a graph showing the load torque (damping force) of Example 1 and Example 2.

  When measuring the load torque, the rotational speed of the rotating body 5 is 20 rpm, the permanent magnet 9 has a diameter of 20 mm, which is approximately the same diameter as the rotating body 5 and is slightly thinner, and has a surface magnetic flux density of 400 mT. The ambient temperature was 24 ° C.

  The measured load torque of Example 1 was 11.50 Nm, while that of Example 2 was 8.36 Nm. In the second embodiment, the load torque is smaller than that in the first embodiment, but it can be made sufficiently larger than the conventional one.

  8 and 10 are cross-sectional views of the rotary damper according to the third embodiment, and FIG. 9 is an enlarged cross-sectional view of a main part of FIG. 8 and 10 correspond to cross sections taken along line II-II in FIG. 1 and line III-III in FIG. 2, respectively. Moreover, in Example 3, the same code | symbol is attached | subjected to the component corresponding to Example 1, and the overlapping description is abbreviate | omitted.

  The rotary damper 1 of the present embodiment is provided with a concave portion 25 on the case 3 side as compared with the first embodiment, and the concave portion is provided on both the case 3 and the rotating body 5.

  The concave portion 25 on the case 3 side is provided on the outer peripheral portion of the bottom plate 13 of the case 3 facing the rotating body 5 in the axial direction at every 60 degrees in the circumferential direction, like the concave portion 21 on the rotating body 5 side. However, the interval between the recesses 25 and the number of the recesses 25 associated therewith are not particularly limited, and can be increased or decreased according to required characteristics. The recesses 25 do not necessarily have to be provided at every predetermined interval, and can be arranged with the intervals between the recesses 25 being varied or arranged in a biased manner in the circumferential direction. Further, the recess 25 on the case 3 side may be shifted radially inward from the recess 21 on the rotating body 5 side.

  Each recess 25 has an elliptical shape having a major axis in the radial direction as shown in the cross section of FIG. 10, and projects slightly in the radial direction from the outer peripheral surface 5 c of the rotating body 5. Accordingly, the recess 25 communicates with both the radial gap D1 and the axial gap D2. The radial dimension of the recess 25 may be set within a range through which the looping magnetic flux M passes, for example, a range facing the outer peripheral portion D2a of the gap D2 in the axial direction as shown in FIG.

  In the present embodiment, the concave portion 25 on the case 3 side stagnates the functional fluid F, so that the functional fluid F is reliably distributed to the outer peripheral portion D2a in the axial gap D2 where the damping force is generated or positioned. Therefore, the damping force can be effectively applied. Such an effect can be obtained even if the recess 21 on the rotating body 5 side is omitted.

  In addition, the third embodiment can achieve the same effects as the first embodiment.

  Instead of the concave portion 25 on the case 3 side, a concave portion 21 to which the shape of the concave portion 25 is applied may be provided on the end surface 5 d of the rotating body 5.

  FIG. 11 is a cross-sectional view of the rotary damper according to the fourth embodiment. FIG. 11 corresponds to a cross section taken along line II-II in FIG. Moreover, in Example 4, the same code | symbol is attached | subjected to the component corresponding to Example 1, and the overlapping description is abbreviate | omitted.

  The rotary damper 1 of the present embodiment is provided with an electromagnet 27 instead of the permanent magnet 9 of the first embodiment. Other configurations of the fourth embodiment are common to the first embodiment.

  In the fourth embodiment, the same function and effect as in the first embodiment can be achieved.

  In the second and third embodiments, the electromagnet 27 can be used in place of the permanent magnet 9.

DESCRIPTION OF SYMBOLS 1 Rotation damper 3 Case 5 Rotating body 7 Damping force generation part 9 Permanent magnet 17 Storage chamber 21 Recess 23, 25 Flat surface 27 Electromagnets D, D1, D2 Gap F Functional fluid
M magnetic flux

Claims (6)

A relatively rotatable case and a rotating body housed in the case;
A damping force generating unit interposing a functional fluid that generates a damping force in the gap by passing the magnetic flux through the gap between the case and the rotating body;
A magnet for generating the magnetic flux over the damping force generation unit;
A recess provided in one or both of the case and the rotating body to hold the functional fluid by partially expanding the gap in the damping force generation unit;
A rotary damper characterized by comprising: The rotary damper according to claim 1,
The recess is provided on one or both surfaces of the case and the rotating body facing each other in the first direction along the rotation radius of the relative rotation, and the rotation of the relative rotation between the case and the rotating body. To the gap in the second direction along the axis,
Rotating damper characterized by that. The rotary damper according to claim 2,
The rotating body has a cylindrical shape,
The case has a cylindrical hole-shaped storage chamber in which the rotating body is rotatably fitted,
A plurality of the recesses are provided at predetermined intervals in the circumferential direction with respect to the outer peripheral surface of the rotating body facing the inner peripheral surface of the housing chamber of the case in the first direction.
Rotating damper characterized by that. The rotary damper according to claim 2 or 3,
Each of the rotating bodies has a flat surface on an outer peripheral portion located on the opposite side in the first direction with respect to a columnar basic shape,
The case has a cylindrical hole-shaped storage chamber in which the rotating body is rotatably fitted,
The concave portion is an arcuate portion that partitions the flat surface between an inner peripheral surface of the storage chamber of the case in the first direction.
Rotating damper characterized by that. The rotary damper according to any one of claims 1 to 4,
The recess is set within a range facing the gap region through which the magnetic flux of the magnet passes.
Rotating damper characterized by that. The rotary damper according to any one of claims 1 to 5,
The recess is provided on either one or both of the surfaces facing each other in the second direction along the rotation axis of the relative rotation of the case and the rotating body,
Rotating damper characterized by that.

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