JP2020023990A - damper - Google Patents

Abstract

To provide a damper which can exert an attenuation force characteristic for suppressing dependency on a rotational speed while saving a space.SOLUTION: A damper 1 comprises a case 10, a shaft 20, a piston 30 and a plurality of granular materials 90. The damper 1 further comprises motion conversion parts (a male screw part 24, a female screw part 31, a groove part 30B and a guide part 13). The case 10 is charged with the plurality of granular materials 90. The shaft 20 is at least partially accommodated in the case 10. The shaft 20 is arranged to be rotatable around a prescribed axis. The piston 30 is formed with a penetration hole 30A, and inserted into the shaft 20. The piston 30 is accommodated in the case 10 to be movable in a direction of the prescribed axis being a rotating axis of the shaft 20. The motion conversion part converts a rotational motion of the shaft 20 to a linear motion in the axial direction of the piston 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a damper.

  Non-Patent Document 1 discloses a conventional damper. This damper is a rotary damper using a granular material. The granular damper is advantageous in that no fluid such as oil is used, so that no liquid leakage occurs and no liquid tightness is required. In the damper, a space in a case is filled with a granular material, and a rotor rotates therein. When the rotor rotates the rotor with respect to the case, the granular material flows with the movement of the rotor, and a torque is generated in a direction opposite to the direction in which the rotor rotates. The torque generated in this manner is a damping force acting in a direction to suppress the rotation of the rotor.

Koichi Hayashi and Koji Imon "Effect of Rotor Position of Rotary Granular Material Damper on Damping Force Characteristics", Proc. Of the 65th Annual Meeting of the Japan Society of Mechanical Engineers, Tokai Branch, March 17-18, 2016, No. . 163-1

  By the way, in a damper using a granular material, it has been found that there is a difference in damping force characteristics between a rotary damper and a direct acting damper. For example, a rotary damper has a greater speed dependency of the damping force than a direct-acting damper. For this reason, in a damper using a granular material, it is necessary to select the type of the damper according to the damping force characteristics. However, when the desired damping force characteristic and the motion of the device are different, for example, when using a damper that suppresses the speed dependence of the damping force in a rotating machine, the input motion is converted to the desired motion. A mechanism had to be provided separately. In this case, more components are required, which leads to an increase in the size of the device.

  The present invention has been made in view of the above-described conventional circumstances, and provides a damper that can exhibit damping force characteristics with reduced dependency on rotation speed while realizing space saving. It is an issue to be solved.

  The damper of the present invention includes a case, a shaft, a piston, a motion conversion unit, and a plurality of granular materials. The case is filled with a plurality of granular materials. The shaft is at least partially housed in the case. The shaft is provided rotatably around a predetermined axis. The piston has a through hole and is inserted into the shaft. The piston is housed in the case so as to be movable in a predetermined axial direction which is a rotation axis of the shaft. The motion converter converts the rotational motion of the shaft into a linear motion of the piston in the axial direction.

  In this damper, when the rotational motion is input and the shaft rotates, the rotational motion of the shaft is converted into a linear motion in the axial direction of the piston by a motion converting unit provided in the damper. That is, the damper converts the rotational motion input to the shaft into a linear motion of the piston, and generates a damping force by the piston moving linearly through the plurality of granular bodies. For this reason, the rotational motion can be attenuated by the damping force generated by the linear motion having small speed dependency as compared with the damping force generated by the rotary motion. As described above, the damper of the present invention can convert the rotary motion into the linear motion and generate the damping force without providing a mechanism for converting the rotary motion into the linear motion separately from the damper. Can be achieved.

  Therefore, the damper of the present invention can exhibit the damping force characteristic in which the dependency on the rotation speed is suppressed while realizing space saving.

  In the damper of the present invention, the plurality of granules may have characteristics of a permanent magnet. And the damper of the present invention can be provided with a coil. In this coil, the number of magnetic lines passing through the inside changes due to the change in the direction of the magnetic lines of force formed by the plurality of granular bodies as the shaft rotates around a predetermined axis, thereby generating an induced electromotive force. In this case, when the shaft rotates and the piston moves in the axial direction accordingly, the granular material in the case flows to generate a damping force. Further, when the granular material filled in the case flows, an induced electromotive force is generated in the coil because the granular material has the characteristics of a permanent magnet. That is, this damper can generate power in addition to generating damping force. Further, since the energy for generating the induced electromotive force further acts as a damping force, a larger damping force can be generated.

  In the damper according to the aspect of the invention, the motion conversion unit can cause the piston to reciprocate linearly by rotating the shaft in one direction. In this case, the piston can be continuously moved without switching the rotation direction of the shaft, and the damping force can be continuously generated.

FIG. 2 is a cross-sectional view schematically illustrating the damper according to the first embodiment. FIG. 2 is a sectional view taken along line II-II of FIG. 1. FIG. 2 is a schematic diagram for explaining a granular material according to Embodiments 1 and 2. It is a figure which shows typically the spiral groove part of the shaft of the damper which concerns on Embodiment 2.

  An embodiment of a damper according to the present invention will be described with reference to the drawings.

<First embodiment>
The damper 1 according to the first embodiment includes a case 10, a shaft 20, a piston 30, a coil 40, and a plurality of granular bodies 90, as shown in FIGS.

  As shown in FIG. 1, the case 10 has a cylindrical shape with both ends opened. The case 10 has internal threads formed on the inner peripheral surfaces of the openings at both ends. In the case 10, bearings 11 and 12 are screwed into female threads having openings at both ends. Openings at both ends of the case 10 are closed by the bearings 11 and 12. A guide 13 is provided on the inner wall of the case 10. As shown in FIGS. 1 and 2, the guide portion 13 is formed to extend in the axial direction of the case 10 and to protrude in the center direction. The guide portion 13 is slidably fitted in a groove portion 30B of the piston 30 described later, and guides the axial movement of the piston 30.

  The bearing portions 11 and 12 are formed in a cylindrical shape having through holes 11A and 12A. In the bearings 11 and 12, both ends of a shaft 20 described later are inserted into the through holes 11A and 12A, respectively. Of the bearing portions 11 and 12, the bearing portion 11 on one end side has a flange portion 11B. The outer diameter of the flange 11 </ b> B is formed larger than the inner diameter of the case 10. The bearing 11 is screwed together with the flange 11 </ b> B in contact with the end surface of the case 10, and is fixed to the case 10 so as not to move in the axial direction. The bearing 11 has a recess 11C. The recess 11C is formed at an end of the bearing 11 opposite to the flange 11B. The recess 11C has an inner diameter larger than the inner diameter of the through hole 11A and is formed coaxially with the through hole 11A. An enlarged diameter portion 21 of a shaft 20 described later is slidably fitted into the concave portion 11C. The bearing 12 on the other end is screwed to the case 10 so that the screwing amount can be adjusted. The bearing portion 12 changes the volume of the internal space of the case 10 by adjusting the screwing amount and moving in the axial direction of the case 10. Thereby, the damper 1 can adjust the filling rate of the granular material described later.

  The shaft 20 has a cylindrical shape. At least a part of the shaft 20 is housed in the case 10. Specifically, in the case of the present embodiment, most of the shaft 20 is housed in the case 10. Both ends 20A and 20B of the shaft 20 are rotatably supported by bearings 11 and 12.

  As shown in FIG. 1, an enlarged diameter portion 21 and a screw portion 22 are formed at one end 20 </ b> A of the shaft 20. The shaft 20 is inserted into the through hole 11 </ b> A of the bearing 11 with the enlarged diameter portion 21 fitted into the recess 11 </ b> C of the bearing 11 and the screw 22 protruding outside the case 10. The enlarged diameter portion 21 is formed with an outer diameter larger than the inner diameter of the through hole 11 </ b> A of the bearing 11. A cap 23 is screwed into the screw portion 22. The cap 23 is formed in a bottomed cylindrical shape whose outer diameter is larger than the inner diameter of the through hole 11 </ b> A of the bearing 11. The end 20 </ b> A of the shaft 20 penetrates the bearing 11 in a form in which the end face of the enlarged diameter portion 21 abuts the bearing 11 in the axial direction and the cap 23 is attached to the screw 22. Thus, the shaft 20 is not rotatable in the axial direction while being rotatably supported by the bearing 11. The outer peripheral surface of the cap 23 is chamfered (not shown) so that a driving force for rotating the shaft 20 can be input.

  The other end 20 </ b> B of the shaft 20 is inserted into a through hole 12 </ b> A of the bearing 12. The end portion 20B of the shaft 20 is inserted into the bearing portion 12 so as to be relatively movable in the axial direction. As described above, the bearing 12 is screwed to the case 10 so as to be movable in the axial direction of the case 10. That is, the bearing 12 moves relative to the case 10 in the axial direction. On the other hand, the end 20 </ b> B of the shaft 20 is immovable in the axial direction with respect to the bearing 11, and the bearing 11 is fixed immovably in the axial direction with respect to the case 10. Therefore, when the bearing 12 moves in the axial direction of the case 10, the bearing 12 moves in the axial direction relatively to the shaft 20.

  As shown in FIG. 1, a male screw portion 24 is formed at an intermediate portion in the longitudinal direction of the shaft 20. The external thread portion 24 is formed so as to be larger in diameter than other portions, and is provided with a thread formed on the outer peripheral surface. The female thread portion 31 of the piston 30 described later is screwed into the male thread portion 24.

  The piston 30 is formed in an annular shape with a through hole 30A formed in the center. The piston 30 is housed in the case 10 movably in the axial direction of the case 10. The outer diameter of the piston 30 is smaller than the inner diameter of the case 10, and a gap is formed between the piston 30 and the inner peripheral surface of the case 10. A groove 30B is formed on the outer peripheral surface of the piston 30. The groove 30 </ b> B is formed so as to be recessed in the center direction of the piston 30. The linear motion of the piston 30 is guided by the groove 30 </ b> B being slidably fitted in the guide portion 13 of the case 10.

  In the piston 30, a female thread portion 31 is formed on the inner peripheral surface of the through hole 30A. The piston 30 is inserted through the shaft 20 in a form in which the female thread 31 is screwed into the external thread 24 of the shaft 20. In the present embodiment, the internal thread portion 31 of the piston 30 and the external thread portion 24 of the shaft 20 function as a motion conversion unit according to the present invention. That is, in the present embodiment, the rotational movement of the shaft 20 is converted into the linear movement of the piston 30 via the external thread 24 and the internal thread 31.

Each of the plurality of granular bodies 90 has a spherical shape. The plurality of particles 90 are elastic bodies made of silicone rubber, which is an elastomer. Each granular material 90 contains neodymium particles having magnetic force.
The plurality of granular bodies 90 have a spherical shape as shown in FIG. These particles 90 are elastic bodies made of silicone rubber, which is an elastomer having a durometer type A hardness (hereinafter, referred to as hardness) of 60. In addition, these particles 90 contain neodymium (Nd) particles 90A. The amount of neodymium (Nd) particles 90A contained in these granular materials 90 is about 60 wt. % (17.78 vol.%). Neodymium (Nd) particles 90A have magnetism. That is, the granular material 90 has magnetism and elasticity. These granular bodies 90 thus formed are magnetized to have a magnetic force. That is, these particles 90 have characteristics of a permanent magnet. These particles 90 are filled in the case 10 at a predetermined filling rate.

  The filling rate is a ratio between the sum of the volumes of the plurality of granular bodies 90 and the inner volume of the case 10. When the filling rate is further increased, the ratio of the volume of the granular material 90 occupying the space in the case 10 becomes larger, so that the piston 30 becomes difficult to move and a larger damping force is generated.

The coil 40 is formed by winding a metal wire, the surface of which is covered with an insulating film, a plurality of times coaxially, and bundling it into a cylindrical shape having a predetermined width in the radial direction and an inner diameter slightly larger than the outer diameter of the case 10. is there. Further, both ends of the metal wire of the coil 40 are drawn out, so that a current generated based on the induced electromotive force generated in the coil 40 is supplied to an electric device or the like provided outside the damper 1. I have. The coil 40 is disposed on the outer peripheral surface of the case 10 such that the cylindrical inner side of the coil 40 inserts the case 10 and follows the outer peripheral surface of the case 10.
In the case of the present embodiment, the case 10, the shaft 20, the piston 30, and the bearings 11 and 12 are each formed of a non-magnetic material, and are formed by a magnetic force acting between the coil 40 and the plurality of granular materials 90. Has no effect.

Next, the operation of the damper 1 of the first embodiment will be described.
When the shaft 20 is relatively rotated with respect to the case 10, the piston 30 moves in the axial direction because the female thread 31 of the piston 30 is screwed into the external thread 24 of the shaft 20. At this time, since the groove 30 </ b> B of the piston 30 is fitted into the guide 13 of the case 10, the piston 30 linearly moves in the axial direction along the guide 13 without rotating relative to the case 10. I do. As described above, in the damper 1, the rotational movement of the shaft 20 is converted into the axial linear movement of the piston 30 by the male screw part 24, the female screw part 31, the guide part 13, and the groove part 30 </ b> B. That is, in the present embodiment, the external thread portion 24 of the shaft 20, the internal thread portion 31 of the piston 30, the guide portion 13 of the case 10, and the groove 30B of the piston 30 function as a motion converting portion according to the present invention. The rotational movement of the piston 20 is converted into the linear movement of the piston 30 in the axial direction.

  When the piston 30 moves in the case 10 in the axial direction, the granular material 90 moves through a gap between the outer peripheral surface of the piston 30 and the inner peripheral surface of the case 10. At this time, between the inner peripheral surface of the case 10 and the granular material 90 abutting on the inner peripheral surface of the case 10, between the adjacent granular materials 90, and the outer peripheral surface of the shaft 20 and the piston 30 and the shaft 20 and the piston 30 A frictional force is generated between the granular material 90 and the outer peripheral surface of the particle. In the damper 1, the shaft 20 rotates in this way, and the piston 30 moves in the axial direction, so that the granular material 90 flows, and a damping force is generated based on a frictional force generated thereby.

  At this time, the direction of the magnetic lines of force formed by the plurality of granular bodies 90 changes with the axial movement of the piston 30, so that the number of magnetic lines of force formed by the plurality of granular bodies 90 passes through the coil 40. As a result, an induced electromotive force is generated in the coil 40. That is, the damper 1 generates power using the coil 40.

  When the direction of relative rotation of the shaft 20 with respect to the case 10 changes, the piston 30 moves in the opposite axial direction because the external thread portion 24 and the internal thread portion 31 are screwed together. The piston 30 moving in the opposite direction causes the granular material 90 to flow in the same manner, whereby the damper 1 generates a damping force and generates power. That is, the damper 1 of the first embodiment generates power while generating a damping force in the bidirectional rotation of the shaft 20.

  When adjusting the magnitude of the damping force of the damper 1, the filling rate of the plurality of granular materials 90 filled in the case 10 is changed. Specifically, in the case of the present embodiment, the volume in the case 10 is changed by adjusting the position of the bearing portion 12 in the axial direction, and the ratio of the volume of the granular material 90 to the internal volume of the case 10 is the filling. It is possible to change the rate.

  Note that the magnitude of the damping force may be adjusted by supplying power to the coil 40 to adjust the magnitude of the damping force. In this case, when power is supplied to the coil 40, a magnetic force is generated in the coil 40. The flow of the granular material 90 in the case 10 is restricted by this magnetic force. For this reason, a larger force is required to flow the granular material 90, and the force for flowing the granular material 90 against this magnetic force can be used as a damping force. Further, the magnitude of the damping force can be adjusted by simply increasing or decreasing the number of the granular bodies 90 to be filled in the case 10.

  As described above, according to the damper 1 of the first embodiment, when the rotational motion is input and the shaft 20 rotates, the external thread portion 24 of the shaft 20 as the motion converting portion provided in the damper 1 and the internal thread portion 31 of the piston 30 The rotational movement of the shaft 20 is converted into an axial linear movement of the piston 30 by the guide portion 13 of the case 10 and the groove 30B of the piston 30. That is, the damper 1 converts the rotational motion input to the shaft 20 into a linear motion of the piston 30, and generates a damping force by the piston 30 moving linearly in the plurality of granular materials 90. For this reason, the rotational motion can be attenuated by the damping force generated by the linear motion having small speed dependency as compared with the damping force generated by the rotary motion. As described above, the damper 1 can convert the rotary motion into the linear motion and generate the damping force without providing a mechanism for converting the rotary motion into the linear motion separately from the damper, thereby simplifying the structure. be able to.

  Therefore, the damper 1 of the first embodiment can exhibit the damping force characteristic in which the dependency on the rotation speed is suppressed while realizing space saving.

  Further, the plurality of granular bodies 90 have characteristics of a permanent magnet. The damper 1 has a coil 40. The number of magnetic lines passing through the inside of the coil 40 changes due to a change in the direction of magnetic lines of force formed by the plurality of granular bodies 90 as the coil 20 rotates around the axis of the shaft 20, thereby generating an induced electromotive force. Thereby, when the shaft 20 rotates and the piston 30 moves in the axial direction with the rotation, the granular material 90 in the case 10 flows to generate a damping force. When the granular material 90 filled in the case 10 flows, an induced electromotive force is generated in the coil 40 because the granular material 90 has the property of a permanent magnet. That is, the damper 1 can generate power in addition to generating damping force. Further, since the energy for generating the induced electromotive force further acts as a damping force, a larger damping force can be generated.

<Embodiment 2>
Next, a second embodiment will be described with reference to FIG.
The damper of the second embodiment has a spiral groove 224 instead of the external thread 24 of the shaft 20 in the damper 1 of the first embodiment (see FIG. 4). In other portions, portions having substantially the same configuration and function as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted.

  As shown in FIG. 4, the spiral groove 224 is provided by forming a spiral groove 224 </ b> A on the outer peripheral surface of the shaft 220. The groove 224A advances obliquely toward one end of the shaft 220, is inverted in a U-shape at one end, and moves toward the other end of the shaft 220 while intersecting the original groove. It progresses obliquely and is formed in a spiral shape so as to be connected to the original groove at the other end. The piston has an engaging portion (not shown) that engages with the spiral groove portion 224 so as to be slidable in the groove 224A. Thus, in the second embodiment, the piston reciprocates in the axial direction by rotation of the shaft 220 in one direction. That is, in the present embodiment, the rotational movement of the shaft 220 is converted into the linear movement of the piston via the spiral groove 224 and the engaging portion of the piston engaged with the spiral groove 224. In the case of the spiral groove portion 224 shown in FIG. 4, the piston makes one reciprocation by rotating the shaft 220 three times.

  Similarly to the first embodiment, the damper of the second embodiment having such a configuration can also exhibit a damping force characteristic with reduced dependency on the rotation speed while realizing space saving.

  The damper according to the second embodiment includes a spiral groove 224 of the shaft 220, an engaging portion (not shown) of a piston slidably engaging the spiral groove 224, the guide 13 of the case 10, and the piston 30. The groove 30 </ b> B functions as the motion conversion unit according to the present invention, and can convert rotation of the shaft 220 in one direction around a predetermined axis into reciprocating motion of the piston. Thereby, the piston can be continuously moved without switching the rotation direction of the shaft 220, and the damping force can be continuously generated. In addition, when a coil is provided, power can be continuously generated.

The present invention is not limited to the first and second embodiments described above with reference to the drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the first and second embodiments, the form in which the coil is provided on the outer peripheral surface of the case is illustrated, but the provision of the coil is not essential. Further, when the coil is provided, it is not limited to the outer peripheral surface of the case, but may be a form in which the coil is provided in a shaft or a piston.
(2) In the first and second embodiments, the elastic body made of silicone rubber, which is an elastomer having a hardness of 60, is exemplified as the plurality of granular bodies, but the material, hardness, and the like of the granular bodies are not particularly limited.
(3) In the first and second embodiments, the sizes of the plurality of granular materials to be filled in the case are uniform, but granular materials having a plurality of types of particle diameters may be filled in the case.
(4) In the first and second embodiments, the granules containing neodymium (Nd) particles are exemplified as the granules having the properties of the permanent magnet, but other materials having the properties of the permanent magnet are used. May be contained. Further, these materials may be compounded. In addition, when the damper does not have a power generation function, the plurality of particles need not have the properties of a permanent magnet.
(5) In the first and second embodiments, the form in which the shaft protrudes from the opening of the case to the outside of the case has been exemplified. However, a form in which substantially the entire shaft is housed in the case may be employed. In this case, for example, an engagement hole may be formed at the axial end of the shaft, and a driving force may be input to the shaft by an engagement protrusion or the like engaged with the engagement hole.
(6) In the first embodiment, an example in which the motion conversion unit is configured to include the external thread of the shaft and the internal thread of the piston has been described, but the motion conversion unit according to the present invention is configured to rotate the shaft. The configuration and the like are not particularly limited as long as the motion is converted into a linear motion in the axial direction of the piston.
(7) In the second embodiment, as the motion conversion unit, the spiral groove is formed on the outer peripheral surface of the shaft, and the spiral groove is formed to reciprocate the piston. It is not limited to. For example, a spiral groove may be formed on the inner peripheral surface of the through hole of the piston.
(8) In the second embodiment, since the spiral groove is formed on the outer peripheral surface of the shaft as shown in FIG. 4, the piston reciprocates one time by rotating the shaft three times. A spiral groove having a form of rotation or four or more rotations may be used. In addition, a form in which the shaft reciprocates once per rotation may be used. That is, the groove may be formed in such a manner that the groove travels obliquely in the axial direction and simply makes one round around the outer circumference of the shaft or the inner circumference of the piston to connect to the original groove.

  DESCRIPTION OF SYMBOLS 1 ... Damper, 10 ... Case, 11, 12 ... Bearing part, 11A, 12A ... Through hole, 11B ... Flange part, 13 ... Guide part, 20, 220 ... Shaft, 20A, 20B ... Shaft end part, 21 ... Expansion Diameter portion, 22: screw portion, 224: spiral groove portion, 224A: spiral groove portion, 23: cap, 24: male thread portion, 30: piston, 30A: through hole, 30B: groove portion, 31: female thread portion, 40 ... coils, 90 ... a plurality of granular materials, 90A ... neodymium particles (magnetic particles)

Claims (3)

Case and
A shaft at least partially housed in the case, and rotatably provided around a predetermined axis;
A piston formed with a through-hole formed therein and inserted through the shaft, and housed in the case so as to be movable in the predetermined axial direction;
A motion conversion unit that converts the rotational motion of the shaft into a linear motion in the axial direction of the piston,
A plurality of granular bodies filled in the case,
A damper comprising: The plurality of granules have properties of a permanent magnet,
A coil is provided that generates an induced electromotive force by changing the direction of magnetic field lines formed by the plurality of granular bodies with the rotation of the shaft around the predetermined axis, thereby changing the number of the magnetic field lines penetrating the inside. The damper according to claim 1, wherein   3. The damper according to claim 1, wherein the motion conversion unit causes the piston to reciprocate linearly by rotating the shaft in one direction. 4.

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