Coupling

Abstract

To provide a coupling capable of easily changing torsional rigidity.SOLUTION: A coupling is equipped with a first joint portion 5 attached to a shaft 2, a second joint portion 6 attached to a shaft 3, an intermediate portion 7 that absorbs torsional vibrations, and a magnetic field generating portion 9. The intermediate portion 7 has a plurality of first blade portions 10 coupled to the first joint portion 5 and extending outward in a diametrical direction, and a plurality of second blade portions 20 coupled to the second joint portion 6 and extending inward in the diametrical direction. Between the adjacent second blade portions 20, a storage space cs in which the first blade portion 10 enters is formed. The storage space cs is filled with magnetic viscous fluid 8. The storage space cs has one side space s1 formed on one side in a circumferential direction, and the other side space s2 formed on the other side. The intermediate portion 7 is formed with a communication channel cp communicating one side space s1 and the other side space s2 with each other. The magnetic field generating portion 9 is provided so as to apply a magnetic field to the magnetic viscous fluid 8 in the communication channel cp.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coupling using a magnetorheological fluid. [Background technology]

[0002] Couplings that connect shafts and transmit rotational power from a driving side to a driven side are known (see, for example, Patent Documents 1 to 4). The couplings disclosed in these documents include a driving side joint portion fixed to the driving side shaft, a driven side joint portion fixed to the driven side shaft, and an intermediate portion connected between these joint portions. In the couplings disclosed in Patent Documents 1 to 3, a leaf spring is included in the intermediate portion, and in the coupling disclosed in Patent Document 4, a rubber material is included in the intermediate portion.

[0003] The general roles of a coupling are (1) to transmit power from the driving side to the driven side, (2) to absorb installation errors between the driving and driven shafts, (3) to absorb vibrations on the driving side, and (4) to prevent heat from the driving motor or the like being transmitted to the driven side. In the couplings disclosed in Patent Documents 1 to 4, with regard to the role of (3) above, vibrations on the driving side are absorbed in the intermediate section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-167743 A [Patent Document 2] JP 2002-372068 A [Patent Document 3] Japanese Patent Publication No. 155335 / 1983 [Patent Document 4] JP 2014-092168 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the torsional vibration absorbed by the coupling can be suppressed by changing the torsional rigidity of the coupling, and the resonance point of the torsional vibration can also be changed.

[0006] However, in the couplings disclosed in Patent Documents 1 to 4, in order to change the torsional rigidity, it is necessary to replace the leaf spring or rubber material used in the middle part of the coupling with one having a different rigidity, or to replace the entire coupling with another coupling having a different torsional rigidity.

[0007] The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a coupling whose torsional rigidity can be easily changed. [Means for solving the problem]

[0008] A coupling according to a first aspect of the present invention includes a first joint part attached to one shaft so as to be non-rotatable relative to the shaft, a second joint part attached to the other shaft so as to be non-rotatable relative to the shaft, and an intermediate part connected between the first joint part and the second joint part for absorbing torsional vibrations, and further includes a magnetic field generating part for generating a magnetic field. The intermediate part includes a plurality of first blade parts connected to the first joint part, extending radially outward, arranged in a circumferential direction, and rotating with the one shaft, and a plurality of second blade parts connected to the second joint part, extending radially inward, arranged in a circumferential direction, and rotating with the other shaft. Between the adjacent second blade parts, a storage space having a volume required for the first blade parts to enter is formed, and the first blade parts are arranged so as to enter the storage space, and the first blade parts and the second blade parts are arranged alternately in the circumferential direction. A magnetorheological fluid is filled between the first blade parts and the second blade parts in the storage space. The accommodating space has a one-side space formed on one circumferential side of the first blade portion and an other-side space formed on the other circumferential side of the first blade portion. A communication flow path is formed in the intermediate portion to communicate the one-side space and the other-side space with each other, and the magnetic field generating unit is provided so as to be able to apply a magnetic field to the magnetorheological fluid in the communication flow path.

[0009] A coupling having such a configuration makes it possible to easily change its torsional rigidity.

[0010] A coupling according to a second aspect of the present invention is the coupling according to the first aspect, wherein the angle through which the first blade portion can rotate circumferentially relative to the second blade portion within the accommodation space is a predetermined angle of 5 degrees or less.

[0011] A coupling according to a third aspect of the present invention is the coupling according to the first or second aspect, wherein the communication passage includes an annular passage formed in an annular shape when viewed in the axial direction.

[0012] A coupling according to a fourth aspect of the present invention is the coupling according to the third aspect, wherein the communicating flow path further includes a one-side orifice opening into the one-side space and the annular flow path, respectively, and an other-side orifice opening into the other-side space and the annular flow path, respectively.

[0013] A coupling according to a fifth aspect of the present invention is the coupling according to the third or fourth aspect, wherein the magnetic field generating unit has a yoke formed in a shape that axially sandwiches the annular flow path, and a coil wound so as to form a magnetic path within the yoke, and when a current is applied to the coil, a magnetic path is formed that penetrates the magnetorheological fluid in the annular flow path. Effect of the Invention

[0014] According to the present invention, it is possible to provide a coupling whose torsional rigidity can be easily changed. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a cross-sectional view taken along a radial direction, showing a characteristic portion of a coupling according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AOA in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A coupling according to an embodiment of the present invention will now be described with reference to the drawings.

[0017] As shown in Fig. 2, the coupling 1 according to this embodiment is connected between a driving-side rotating shaft 2 and a driven-side rotating shaft 3, and includes a first joint section 5, a second joint section 6, an intermediate section 7, a magnetorheological fluid 8, and a magnetic field generating section 9. In this specification, the driving-side rotating shaft may be referred to as the "driving shaft" and the driven-side rotating shaft may be referred to as the "driven shaft." In addition, in this specification, directions may be referred to with the driving shaft side as the top and the driven shaft side as the bottom.

[0018] The first joint part 5 is attached to the drive-side rotating shaft 2 so as to be non-rotatable relative to the drive-side rotating shaft 2, and rotates integrally with the drive-side rotating shaft 2. The first joint part 5 is desirably made of a non-magnetic material.

[0019] The second joint part 6 is attached to the driven-side rotating shaft 3 so as to be non-rotatable relative to the driven-side rotating shaft 3, and rotates integrally with the driven-side rotating shaft 3. The second joint part 6 is desirably made of a non-magnetic material.

[0020] The intermediate section 7 is connected between the first joint section 5 and the second joint section 6. In this embodiment, the intermediate section 7 has a plurality of first blade sections 10, a first blade section rotating shaft 11, bearing housing members 12, 14, bearings 13, 15, a plurality of second blade sections 20, a first cylindrical section 21, a second cylindrical section 22, and a third cylindrical section 23.

[0021] The first blade portion rotating shaft 11 is a rotating shaft that is integrally connected to the first joint portion 5 on the axis N and extends in the direction of the axis N from the first joint portion 5 toward the second joint portion 6. The first blade portion rotating shaft 11 rotates in conjunction with the rotation of the drive-side rotating shaft 2. The first blade portion rotating shaft 11 is desirably made of a non-magnetic material.

[0022] As shown in FIG. 2, the first blade portion 10 is a blade-shaped portion extending radially outward from an approximately axially intermediate position of the first blade portion rotating shaft 11. As shown in FIG. 1, the first blade portions 10 are arranged in the circumferential direction at equal angles and extend radially from the first blade portion rotating shaft 11 with the axis N as the center. The first blade portions 10 rotate together with the rotation of the drive-side rotating shaft 2 via the first joint portion 5 and the first blade portion rotating shaft 11. As shown in FIG. 1, the first blade portion 10 is formed in a rectangular shape when viewed in the axial direction. Also, as shown in FIG. 2, the first blade portion 10 is formed in a rectangular shape when viewed in the radial direction. It is preferable that the first blade portion 10 is made of a non-magnetic material.

[0023] As shown in Figs. 1 to 3, the first cylindrical portion 21 is formed in a cylindrical shape extending in the direction of the axis N, and is disposed radially outward of the multiple first blade portions 10. As shown in Figs. 2 and 3, the drive shaft 2 side end face of the first cylindrical portion 21 is in relatively rotatable contact with the driven shaft 3 side end face of the first joint portion 5. The first cylindrical portion 21 is a component of the intermediate portion 7, and also serves as a component of the magnetic field generating portion 9 (first inner yoke 21) as described later. Therefore, the first cylindrical portion 21 is made of a magnetic material.

[0024] As shown in Fig. 2 and Fig. 3, the second cylindrical portion 22 is composed of an inner cylindrical portion 22a and an outer cylindrical portion 22b, and the inner diameter of the first cylindrical portion 21 and the inner diameter of the inner cylindrical portion 22a are the same, and the outer diameter of the first cylindrical portion 21 and the outer diameter of the outer cylindrical portion 22b are the same. The end surface of the second cylindrical portion 22 on the drive shaft 2 side is connected to the end surface of the first cylindrical portion 21 on the driven shaft 3 side so as not to rotate relative to each other. As described later, the second cylindrical portion 22 forms an annular flow passage kp between the outer cylindrical portion 22b and the inner cylindrical portion 22a. The second cylindrical portion 22 is composed of a non-magnetic material.

[0025] As shown in Figs. 2 and 3, the third cylindrical portion 23 is formed in a cylindrical shape having the same diameter as the third cylindrical portion 23 and the second cylindrical portion 22. The drive shaft 2 side end surface of the third cylindrical portion 23 is connected to the driven shaft 3 side end surface of the second cylindrical portion 22 so as not to rotate relatively. Furthermore, the driven shaft 3 side end surface of the third cylindrical portion 23 is connected to the drive shaft 2 side end surface of the second joint portion 6 so as not to rotate relatively. As a result, the first cylindrical portion 21, the second cylindrical portion 22, and the third cylindrical portion 23, which are connected to each other so as not to rotate relatively, rotate together with the driven shaft 3 via the second joint portion 6. The third cylindrical portion 23 is a component of the intermediate portion 7, and also serves as a component (second inner yoke 23) of the magnetic field generating portion 9, as described later. Therefore, the third cylindrical portion 23 is made of a magnetic material.

[0026] As shown in FIG. 3, the second blade portion 20 is a blade-shaped portion extending radially inward from the first cylindrical portion 21 at a position approximately on the driven shaft 3 side of the first cylindrical portion 21 and at the same height position in the axial direction as the first blade portion 10. As shown in FIG. 1, the multiple second blade portions 20 are arranged in the circumferential direction at equal angles and extend radially from the first cylindrical portion 21 around the axis N. The multiple second blade portions 20 rotate together with the driven-side rotating shaft 3 via the first cylindrical portion 21, the second cylindrical portion 22, the third cylindrical portion 23, and the second joint portion 6. As shown in FIG. 1, the second blade portion 20 is formed in a fan shape when viewed in the axial direction. It is preferable that the second blade portion 20 is made of a non-magnetic material.

[0027] As shown in FIG. 1, between the second blades 20 adjacent to each other in the circumferential direction, a storage space cs having a volume necessary for the first blade 10 to enter is formed. That is, a plurality of storage spaces cs are formed in the middle section 7 in a line in the circumferential direction. One storage space cs is formed corresponding to one first blade 10, and the first blade 10 is arranged so as to enter the storage space cs, and the first blade 10 and the second blade 20 are alternately arranged in the circumferential direction. In the storage space cs, the first blade 10 can rotate relative to the second blade 20. Therefore, the storage space cs has a small play (angular interval) corresponding to a predetermined angle between the first blade 10 and the adjacent second blade 20 in the circumferential direction. Specifically, the angle at which the first blade 10 can rotate relative to the second blade 20 in the circumferential direction in the storage space cs is a predetermined angle of 5 degrees or less. That is, the storage space cs has a small space (one-side space s1) formed on one circumferential side of the first blade portion 10, and a small space (other-side space s2) formed on the other circumferential side of the first blade portion 10.

[0028] The accommodation space cs is filled with magnetorheological fluid 8 between the first blade portion 10 and the second blade portion 20. That is, in the accommodation space cs, one side space s1 and the other side space s2 are each filled with magnetorheological fluid 8. In this embodiment, the magnetorheological fluid 8 is filled in the areas shaded gray in Figs. 1 to 3.

[0029] The magnetorheological fluid 8 is a liquid in which magnetic particles are dispersed in a dispersion medium. For example, nano-sized metal particles (metal nanoparticles) can be used as the magnetic particles. The magnetic particles are made of a magnetizable metal material, and although there is no particular limitation on the metal material, a soft magnetic material is preferable. Examples of the soft magnetic material include alloys such as iron, cobalt, nickel, and permalloy. Although there is no particular limitation on the dispersion medium, one example is hydrophobic silicone oil. The blending amount of the magnetic particles in the magnetorheological fluid can be, for example, 3 to 40 vol%. It is also possible to add various additives to the magnetorheological fluid in order to obtain various desired characteristics.

[0030] The shape of the accommodation space cs is preferably a substantially sector shape expanding in the circumferential direction as shown in FIG. 1. In other words, the accommodation space cs is preferably formed in a shape in which the circumferential distance increases from the radially inner side to the radially outer side. This makes it easy to push out the magnetorheological fluid 8 filled in the one-side space s1 or the other-side space s2 toward the first orifice оr1 or the second orifice оr2 described later when the first blade portion 10 rotates relative to the second blade portion 20 in the accommodation space cs. The radially outer wall surface of the accommodation space cs is formed by the inner surface of the first cylindrical portion 21, and the radially inner wall surface of the accommodation space cs is formed by the first blade portion rotation shaft 11.

[0031] As shown in Figures 2 and 3, a bearing housing member 12 is fixed to the drive shaft 2 side of the second blade portion 20, radially inside the first cylindrical portion 21. A bearing 13 is interposed between the bearing housing member 12 and the first blade portion rotating shaft 11. The bearing 13 supports the first blade portion rotating shaft 11 at the intermediate portion 7 so that it can rotate on the axis N. A part of the end face of the bearing housing member 12 on the driven shaft 3 side forms a wall surface of the accommodation space cs on the drive shaft 2 side (the ceiling surface of the accommodation space cs). It is preferable that the bearing housing member 12 is made of a non-magnetic material.

[0032] Similarly, as shown in Figs. 2 and 3, a bearing housing member 14 is fixed to the driven shaft 3 side of the second blade portion 20, radially inward of the first cylindrical portion 21, the second cylindrical portion 22, and the third cylindrical portion 23. A bearing 15 is interposed between the bearing housing member 14 and the first blade portion rotating shaft 11. The bearing 15 supports the first blade portion rotating shaft 11 at the intermediate portion 7 so that the first blade portion rotating shaft 11 is rotatable on the axis N. A part of the end face of the bearing housing member 14 on the drive shaft 2 side forms a wall surface of the accommodation space cs on the driven shaft 3 side (the bottom surface of the accommodation space cs). It is preferable that the bearing housing member 14 is made of a non-magnetic material.

[0033] A communication flow passage cp that communicates the one side space s1 and the other side space s2 with each other is formed in the intermediate portion 7. The communication flow passage cp includes a first orifice or1, a second orifice or2, and an annular flow passage kp.

[0034] 2 and 3, an annular flow passage kp, which is an annular flow passage when viewed in the axial direction, is formed in the second cylindrical portion 22 so that the magnetorheological fluid 8 flows in the circumferential direction inside the second cylindrical portion 22. The annular flow passage kp is open to the drive shaft 2 side end face and the driven shaft 3 side end face of the second cylindrical portion 22, and is a flow passage formed to go around the inside of the second cylindrical portion 22 in the circumferential direction. The driven shaft 3 side end face of the first cylindrical portion 21 forms the top surface of the annular flow passage kp, and the drive shaft 2 side end face of the third cylindrical portion 23 forms the bottom surface of the annular flow passage kp.

[0035] 1 and 2, a first orifice OR1 opening into one side space s1 and a second orifice OR2 opening into the other side space s2 are formed in the first cylindrical portion 21. That is, the first orifice OR1 and the second orifice OR2 each open into the inner surface of the first cylindrical portion 21 that forms the radially outer wall surface of the accommodation space cs.

[0036] Furthermore, the first orifice оr1 and the second orifice оr2 each extend in the axial direction through the first cylindrical portion 21 from the opening on the housing space cs side, and each also opens on the top surface of the annular flow passage kp (the end surface of the first cylindrical portion 21 on the driven shaft 3 side). As a result, the first orifice оr1 communicates the one-side space s1 with the annular flow passage kp, and the second orifice оr2 communicates the other-side space s2 with the annular flow passage kp. In this embodiment, as shown in FIG. 2, the flow passage cross-sectional area of ​​each of the first orifice оr1 and the second orifice оr2 is smaller than the flow passage cross-sectional area of ​​the annular flow passage kp, but is not limited to this.

[0037] That is, the one-side space s1 and the other-side space s2 are communicated with each other through the first orifice оr1, the second orifice оr2, and the annular passage kp. Therefore, the first orifice оr1, the second orifice оr2, and the annular passage kp configure a communication passage cp that communicates the one-side space s1 and the other-side space s2 with each other.

[0038] The magnetorheological fluid 8 can flow from the one-side space s1 to the other-side space s2, or from the other-side space s2 to the one-side space s1, by flowing through the communicating flow passage cp. That is, when the first blade portion 10 rotates relative to the second blade portion 20 toward one side in the circumferential direction, the volume of the one-side space s1 decreases and the volume of the other-side space s2 increases. Accordingly, the magnetorheological fluid 8 filled in the one-side space s1 can flow through the communicating flow passage cp into the other-side space s2. When the first blade portion 10 rotates relative to the second blade portion 20 toward the other side in the circumferential direction, the volume of the other-side space s2 decreases and the volume of the one-side space s1 increases. Accordingly, the magnetorheological fluid 8 filled in the other-side space s2 can flow through the communicating flow passage cp into the one-side space s1.

[0039] That is, the energy of the relative rotation (including the relative swing) of the first blade portion 10 with respect to the second blade portion 20 in the accommodation space cs is converted into the flow energy of the magnetorheological fluid 8.

[0040] In order to seal the one-side space s1 and the other-side space s2 from each other within the storage space cs, a sealing member se2 that fills the gap is interposed between the first blade portion 10 and a member surrounding the first blade portion 10 in the axial or radial direction.

[0041] Specifically, as shown in Fig. 1, a seal member se2 is interposed between the inner surface of the first cylindrical portion 21 and the radially outer surface of the first blade portion 10. A groove extending in the axial direction and recessed radially outward is formed on the inner surface of the first cylindrical portion 21, and the seal member se2 is fitted into the groove. The seal member se2 is in slidable contact with the radially outer surface of the first blade portion 10. It is preferable that the seal member se2 is made of a non-magnetic material.

[0042] Furthermore, although not shown, the seal member se2 is preferably interposed between the axial side of the first blade portion 10 facing the drive shaft 2 and the bottom surface of the bearing housing member 12. Similarly, the seal member se2 is preferably interposed between the axial side of the first blade portion 10 facing the driven shaft 3 and the top surface of the bearing housing member 14.

[0043] Also, as shown in Figures 1 and 2, in order to seal adjacent storage spaces cs from each other, a sealing member se1 that fills the gap is interposed between the second blade portion 20 and a member surrounding the second blade portion 20 in the axial or radial direction.

[0044] Specifically, as shown in FIG. 1, a groove extending in the axial direction and recessed toward the radially outward is formed on the radially inner side surface of the second blade portion 20, and a seal member se1 is fitted into the groove. The seal member se1 in this portion is in slidable contact with the first blade portion rotating shaft 11. Furthermore, as shown in FIG. 3, a groove extending in the radial direction and recessed toward the drive shaft 2 side is formed on the bottom surface (driven shaft 3 side) of the second blade portion 20, and a seal member se1 is fitted into the groove. The seal member se1 in this portion is in contact with the top surface of the bearing housing member 14. Similarly, a groove extending in the radial direction and recessed toward the driven shaft 3 side is formed on the top surface (drive shaft 2 side) of the second blade portion 20, and a seal member se1 is fitted into the groove. The seal member se1 in this portion is in contact with the bottom surface of the bearing housing member 12. It is preferable that the seal member se1 is made of a non-magnetic material.

[0045] The magnetic field generating unit 9 generates a magnetic field to be applied to the magnetorheological fluid 8. In this embodiment, the magnetic field generating unit 9 includes a yoke and a coil 25.

[0046] 2 and 3, in this embodiment, the yoke is made up of a first inner yoke 21, a second inner yoke 23, and an outer yoke 24. Naturally, all of the members constituting the yoke are made of magnetic material.

[0047] The first inner yoke 21 is a first cylindrical portion 21. The second inner yoke 23 is a third cylindrical portion 23. These form a magnetic path extending in the axial direction at a position radially outside the intermediate portion 7.

[0048] The first inner yoke 21 and the second inner yoke 23 axially sandwich a second cylindrical portion 22 having an annular flow passage kp therein.

[0049] One end face of the outer yoke 24 faces the radial outer surface of the first inner yoke 21 via a small gap, and the other end face faces the radial outer surface of the second inner yoke 23 via a small gap. In this embodiment, the outer yoke 24 is formed in an overall annular shape, and has a substantially C-shaped cross section.

[0050] As shown in Fig. 3, bearing housing members 16, 18 are fixed to both axial sides of the outer yoke 24. A bearing 17 is interposed between the bearing housing member 16 and the first joint part 5, and a bearing 19 is interposed between the bearing housing member 18 and the second joint part 6. Therefore, the first joint part 5, the second joint part 6, and the intermediate part 7 are rotatable relative to the outer yoke 24 and the coil 25. The bearing housing members 16, 18 are preferably made of a non-magnetic material.

[0051] 2 and 3, the coil 25 is wound around the inner side of the outer yoke 24. A current of a desired value can be supplied to the coil 25 from a power supply unit 31. When a current is supplied to the coil 25, the coil 25 can form a magnetic path within the yoke. When a magnetic path is formed within the yoke, a magnetic field is applied to the magnetorheological fluid 8 within the annular flow path kp sandwiched between the first inner yoke 21 and the second inner yoke 23.

[0052] In the coupling 1 having the above-mentioned configuration, when a current is applied to the coil 25 by the power supply unit 31, a magnetic path is formed in the yoke along the direction of the arrow P in Fig. 2 and Fig. 3, for example. In particular, a magnetic path is formed that penetrates the magnetorheological fluid 8 flowing in the annular flow path kp, and the magnetorheological fluid 8 exhibits a viscosity according to the strength of the applied magnetic field. Then, by changing the value of the current applied to the coil 25, the viscosity of the magnetorheological fluid 8 can be changed, and therefore the torsional rigidity of the coupling 1 can also be changed.

[0053] In detail, when a magnetic field is applied to the magnetorheological fluid 8 filling the annular flow passage kp, viscosity is generated in the magnetorheological fluid 8 in the annular flow passage kp. At this time, when a torsional vibration is input from the drive-side rotating shaft 2 to the coupling 1, the first blade portion 10 rotates (oscillates) in the circumferential direction in the accommodation space cs via the first joint portion 5 and the first blade portion rotating shaft 11. In response to the rotation of the first blade portion 10, the volumes of the one-side space s1 and the other-side space s2 change, and the magnetorheological fluid 8 tries to move between the one-side space s1 and the other-side space s2 via the communicating flow passage cp. The magnetorheological fluid 8 flows through the annular flow passage kp of the communicating flow passage cp, but since a magnetic field is applied in the annular flow passage kp, resistance according to viscosity is generated in the flow between the one-side space s1 and the other-side space s2. Therefore, the energy accompanying the rotational vibration (oscillation) of the first blade portion 10 is dissipated by the resistance when the magnetorheological fluid 8 flows through the communicating flow passage cp. In other words, the torsional rigidity of the entire coupling 1 can be changed by the magnetic field generated by the magnetic field generating section 9, so that the torsional vibration input from the drive-side rotating shaft 2 can be suppressed.

[0054] As described above, according to the coupling 1 of this embodiment, the torsional rigidity of the coupling 1 can be changed simply by changing the value of the current applied to the coil 25. Therefore, the torsional vibration input to the coupling 1 can be easily suppressed, and the resonance point of the torsional vibration can also be easily changed.

[0055] Furthermore, in the coupling 1 having the above-mentioned configuration, the angle by which the first blade portion 10 can rotate circumferentially relative to the second blade portion 20 within the accommodation space cs is a predetermined angle of 5 degrees or less, so that large rotations (rotations exceeding the predetermined angle) input from the drive-side rotating shaft 2 are transmitted to the driven-side rotating shaft 3, while minute rotational vibrations (oscillations) input from the drive-side rotating shaft 2 that are equal to or smaller than the predetermined angle can be absorbed as fluid resistance of the magnetorheological fluid 8 and are suppressed.

[0056] Furthermore, in the coupling 1 having the above-mentioned configuration, the communication flow path cp includes the annular flow path kp formed in an annular shape when viewed in the axial direction, so that the magnetorheological fluid 8 can be easily caused to flow between the one-side space s1 and the other-side space s2 formed side by side in the circumferential direction. Of course, even in this case, it is possible to generate fluid resistance of the magnetorheological fluid 8 in response to the magnetic field applied to the magnetorheological fluid 8 by the magnetic field generating unit 9.

[0057] Furthermore, in the coupling 1 having the above-mentioned configuration, the communicating flow passage cp further includes a one-side orifice or1 that opens into the one-side space s1 and the annular flow passage kp, respectively, and an other-side orifice or2 that opens into the other-side space s2 and the annular flow passage kp, respectively, so that it becomes easy to flow the magnetorheological fluid 8 between the one-side space s1 and the annular flow passage kp, and also becomes easy to flow the magnetorheological fluid 8 between the other-side space s2 and the annular flow passage kp.

[0058] Furthermore, in the coupling 1 having the above-mentioned configuration, the magnetic field generating unit 9 has a yoke formed in a shape that axially sandwiches the annular flow path kp, and a coil 25 wound so as to form a magnetic path within the yoke. When a current is applied to the coil 25, a magnetic path is formed that penetrates the magneto-rheological fluid 8 within the annular flow path kp, so that a concentrated magnetic field can be applied to the magneto-rheological fluid 8 flowing within the annular flow path kp, and the viscosity of the magneto-rheological fluid 8 can be easily changed.

[0059] <Modification> In the above-described embodiment of the present invention, the communication flow path cp is constituted by the first orifice оr1, the second orifice оr2, and the annular flow path kp, but the openings of the first orifice оr1 and the second orifice оr2 on the sides away from the accommodation space may be directly connected to each other to constitute an orifice (not shown) that opens into the one-side space s1 and the other-side space s2, respectively. Even in this case, the magnetic field generating unit 9 can form a magnetic path that penetrates the magnetorheological fluid 8 flowing through the orifice, so that the torsional rigidity of the coupling 1 can be changed simply by changing the current value applied to the coil 25. Therefore, the torsional vibration input to the coupling 1 can be easily suppressed, and the resonance point of the torsional vibration can also be easily changed. [Industrial Applicability]

[0060] The present invention can be applied, for example, to a coupling for connecting shafts. [Explanation of symbols]

[0061] 1 Coupling 2 Drive side rotating shaft (drive shaft) 3 Driven rotating shaft (driven shaft) 5 First joint 6 Second joint 7. Middle Section 8. Magnetorheological Fluids 9. Magnetic field generating unit 10 First wing 11 First blade rotating shaft 20 Second wing 21 First cylindrical portion (first inner yoke) 22 Second cylindrical section 23 Third cylindrical portion (second inner yoke) 24 Outer Yoke 25 Coil 31 Power supply unit cs Storage space s1 One-sided space s2 Other side space cp Connecting flow channel kp Annular flow path оr1 First orifice оr2 Second orifice N axis

Claims

1. A first joint portion that is attached to one of the shafts so as not to rotate relative to the one of the shafts; A second joint portion that is attached to the other shaft so as not to rotate relative to the other shaft; an intermediate portion connected between the first joint portion and the second joint portion and configured to absorb torsional vibration; A coupling comprising: Further comprising a magnetic field generating unit that generates a magnetic field, The intermediate portion is a plurality of first blade portions connected to the first joint portion, extending radially outward, arranged in a circumferential direction, and rotating together with the one shaft; A plurality of second blade portions that are connected to the second joint portion, extend radially inward, are arranged in a circumferential direction, and rotate together with the other shaft; having Between the adjacent second blade portions, an accommodation space having a volume necessary for the first blade portion to enter is formed, The first blade portion is disposed so as to enter the accommodation space, and the first blade portion and the second blade portion are alternately arranged in a circumferential direction, A magnetorheological fluid is filled between the first blade portion and the second blade portion in the accommodation space, The accommodation space has a one-side space formed on one circumferential side of the first blade portion and a second-side space formed on the other circumferential side of the first blade portion, A communication flow path is formed in the intermediate portion, the communication flow path connecting the one-side space and the other-side space to each other, the magnetic field generating unit is provided so as to be able to apply a magnetic field to the magnetorheological fluid in the communicating flow path, The communication passage includes an annular passage formed in an annular shape when viewed in the axial direction, The magnetic field generating unit is a yoke formed in a shape that sandwiches the annular flow passage in the axial direction; A coil wound so as to form a magnetic path within the yoke; having When a current is applied to the coil, a magnetic path is formed through the magnetorheological fluid in the annular flow channel. A coupling characterized by:

2. 2. The coupling according to claim 1, The angle at which the first blade portion can rotate relative to the second blade portion in the circumferential direction within the accommodation space is a predetermined angle of 5 degrees or less. A coupling characterized by:

3. 3. The coupling according to claim 1 or 2, the communication flow passage further includes a first-side orifice that opens into the first-side space and the annular flow passage, respectively, and a second-side orifice that opens into the second-side space and the annular flow passage, respectively. A coupling characterized by:

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