JP7599987B2 - Coupling - Google Patents

Description

The present invention relates to a coupling using a magnetorheological fluid.

Couplings that connect shafts and transmit rotational power from the driving side to the driven side are known (see, for example, Patent Documents 1 to 4). The couplings disclosed in these documents include a driving side joint portion that is fixed to the driving side shaft, a driven side joint portion that is fixed to the driven side shaft, and an intermediate portion that is 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.

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 from 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 middle section.

JP 2012-167743 A JP 2002-372068 A Japanese Unexamined Patent Publication No. 155335/1983 JP 2014-092168 A

By the way, 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.

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.

The present invention was devised in light of the above situation, and aims to provide a coupling whose torsional rigidity can be easily changed.

The coupling according to the first aspect of the present invention comprises a first joint part that is attached to one shaft so as to be non-rotatable relative to the other shaft, a second joint part that is attached to the other shaft so as to be non-rotatable relative to the other shaft, and an intermediate part that is connected between the first joint part and the second joint part and absorbs torsional vibrations, and further comprises a magnetorheological fluid interposed between the first joint part and the second joint part, and a magnetic field generating part that generates a magnetic field to be applied to the magnetorheological fluid.

A coupling with this configuration allows the torsional rigidity to be easily changed.

The coupling according to the second aspect of the present invention is the coupling according to the first aspect, in which the middle part has a leaf spring that elastically deforms in the torsional direction.

The coupling according to the third aspect of the present invention is the coupling according to the second aspect, in which the leaf spring is made of a magnetic material, and the magnetic field generating unit has a yoke formed in a shape that sandwiches both sides of the leaf spring with a gap therebetween, and a coil wound so as to form a magnetic path within the yoke. At least a portion of the magnetorheological fluid is interposed in the gap between the leaf spring and the yoke, and when a current is applied to the coil, a magnetic path is formed that penetrates the magnetorheological fluid interposed in the gap between the leaf spring and the yoke.

The coupling according to the fourth aspect of the present invention is the coupling according to the second aspect, wherein the intermediate portion has a plurality of the leaf springs, the plurality of leaf springs being made of a magnetic material, and adjacent ones are connected to each other via a connecting member so as to be elastically deformable in a torsional direction. The magnetic field generating portion has a yoke formed in a shape that sandwiches both sides of each leaf spring with a gap therebetween, and a coil wound so as to form a magnetic path within the yoke. At least a portion of the magnetorheological fluid is interposed in the gap between the leaf springs and the yoke, and when a current is applied to the coil, a magnetic path is formed that penetrates the magnetorheological fluid interposed in the gap between the plurality of leaf springs and the yoke.

The coupling according to the fifth aspect of the present invention is the coupling according to the first aspect, in which the middle part has rubber or resin that elastically deforms in the torsional direction.

The coupling according to the sixth aspect of the present invention is the coupling according to the fifth aspect, in which the rubber or resin functions as a vibration absorbing material that absorbs torsional vibrations and also functions as a sealing material that prevents the magnetorheological fluid from leaking out from between the first joint part and the second joint part.

The present invention provides a coupling whose torsional rigidity can be easily changed.

1 is a cross-sectional view showing a coupling according to a first embodiment of the present invention. FIG. 2 is an enlarged view of part A in FIG. FIG. 2 is an enlarged view of a portion B in FIG. 1 , in which the magnetorheological fluid (filled in gray) is omitted. FIG. 2 is a diagram showing a modified example of the first embodiment of the present invention, illustrating a portion corresponding to part B in FIG. 1. FIG. 6 is a cross-sectional view showing a coupling according to a second embodiment of the present invention.

First Embodiment
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A coupling according to a first embodiment of the present invention will now be described with reference to the drawings.

As shown in Figures 1 to 3, the coupling 1 according to this embodiment is connected between a driving shaft 2 and a driven shaft 3, and includes a first joint part 5, a second joint part 6, an intermediate part 7, a magnetorheological fluid 8, and a magnetic field generating part 9.

The first joint part 5 is attached to the drive-side rotating shaft 2 so that it cannot rotate relative to the drive-side rotating shaft 2, and rotates integrally with the drive-side rotating shaft 2. It is preferable that the first joint part 5 is made of a non-magnetic material, except for the first inner yoke 15a described below.

The second joint part 6 is attached to the driven rotating shaft 3 so that it cannot rotate relative to the driven rotating shaft 3, and rotates integrally with the driven rotating shaft 3. It is preferable that the second joint part 6 is made of a non-magnetic material, except for the second inner yoke 15b described below.

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 is configured using a plurality of leaf springs 11 and a connecting member 12.

The multiple leaf springs 11 are each made of a disk-shaped member made of a magnetic material. When a torsional displacement occurs between the driving side rotating shaft 2 and the driven side rotating shaft 3, each leaf spring 11 elastically deforms in the torsional direction. Therefore, when torsional vibration is input from the driving side rotating shaft 2 or the driven side rotating shaft 3, each leaf spring 11 absorbs the torsional vibration while elastically deforming in the torsional direction. The multiple leaf springs 11 are arranged in parallel with a gap between them, and are perpendicular to the rotation axis N.

As shown in FIG. 3, adjacent leaf springs 11 are connected to each other via connecting members 12. Of the multiple leaf springs 11, the leaf spring 11 located closest to the first joint 5 (hereinafter also referred to as the "first leaf spring 11A") is connected to the first joint 5 via multiple connecting members 13. Of the multiple leaf springs 11, the leaf spring 11 located closest to the second joint 6 (hereinafter also referred to as the "second leaf spring 11B") is connected to the second joint 6 via multiple connecting members 14.

In this embodiment, the connecting members 12, 13, and 14 are arranged at equal intervals on a circle centered on the rotation axis N. The connecting members 12, 13 arranged on the surface of the first joint section 5 side of each leaf spring 11 and the connecting members 12, 14 arranged on the surface of the second joint section 6 side are arranged at different circumferential positions. In this embodiment, bolts are used as the connecting members 12, 13, and 14. Note that the connecting members 12 are not limited to bolts, and may be, for example, members of a predetermined shape welded between the leaf springs 11, between the first leaf spring 11A and the first joint section 5, and between the second leaf spring 11B and the second joint section 6 to connect them to each other.

The magnetorheological fluid 8 is interposed between the first joint 5 and the second joint 6, and at least a part of it is interposed in the gap between each leaf spring 11 and the yoke 15 described later. In this embodiment, the magnetorheological fluid 8 is enclosed in the gray-colored area in FIG. 1. This magnetorheological fluid 8 is a liquid in which magnetic particles are dispersed in a dispersion medium. As the magnetic particles, for example, nano-sized metal particles (metal nanoparticles) can be used. The magnetic particles are made of a magnetizable metal material, and although there is no particular restriction on the metal material, a soft magnetic material is preferable. Examples of soft magnetic materials include alloys such as iron, cobalt, nickel, and permalloy. The dispersion medium is not particularly limited, but one example is hydrophobic silicone oil. The amount of magnetic particles in the magnetorheological fluid can be, for example, 3 to 40 vol%. Various additives can also be added to the magnetorheological fluid to obtain various desired characteristics.

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 15 and a coil 16.

As shown in FIG. 2, in this embodiment, the yoke 15 is composed of a first inner yoke 15a, a second inner yoke 15b, an intermediate yoke 15c, and an outer yoke 15d. Naturally, all of the components that make up the yoke 15 are made of magnetic material.

The first inner yoke 15a is fitted into an annular recess 5a formed in the first joint part 5 and is exposed radially outward and toward the middle part 7 in the direction of the rotation axis N. In this embodiment, the first inner yoke 15a is made of an annular member with a rectangular cross section and is part of the first joint part 5.

The second inner yoke 15b is fitted into an annular recess 6a formed in the second joint 6 and is exposed radially outward and toward the middle portion 7 in the direction of the rotation axis N. In this embodiment, the second inner yoke 15b is made of an annular member with a rectangular cross section and is part of the second joint 6.

The intermediate yoke 15c is disposed between the first inner yoke 15a and the second inner yoke 15b. This intermediate yoke 15c is not fixed in the rotational direction relative to the first inner yoke 15a and the second inner yoke 15b. In other words, the intermediate yoke 15c is in a state in which it can rotate slightly relative to the first inner yoke 15a and the second inner yoke 15b. In this embodiment, the intermediate yoke 15c is formed in an annular shape and has a protruding strip 15ca on its inner periphery that fits between the leaf springs 11.

One end face of the outer yoke 15d faces the side of the first inner yoke 15a via a small gap, and the other end face faces the side of the second inner yoke 15b via a small gap. In this embodiment, the outer yoke 15d is generally formed in an annular shape, and has a cross section that is approximately C-shaped.

As shown in FIG. 1, bearing housing members 17 are fixed to both sides of the outer yoke 15d. A bearing 18 is interposed between one bearing housing member 17 and the first joint part 5, and a bearing 18 is interposed between the other bearing housing member 17 and the second joint part 6. Therefore, the first joint part 5, the second joint part 6, the intermediate part 7, the first inner yoke 15a, and the second inner yoke 15b are rotatable relative to the outer yoke 15d and the coil 16. It is preferable that the bearing housing members 17 are made of a non-magnetic material.

In this embodiment, as shown in FIG. 2, the inner part of the yoke 15, which is made up of the first inner yoke 15a, the second inner yoke 15b, and the intermediate yoke 15c, is formed in a shape that sandwiches both sides of the outer periphery of the leaf spring 11 via a minute gap 20.

The coil 16 is wound around the inside of the outer yoke 15d. A current of a desired value can be supplied to the coil 16 from the power supply unit 21.

When a current is applied to the coil 16 by the power supply unit 21 in the coupling 1 having the above-mentioned configuration, a magnetic path is formed in the yoke 15, for example along the direction of the arrow P in FIG. 1. In particular, a magnetic path is formed that penetrates the magnetorheological fluid 8 present in the minute gap 20 between both sides of the leaf spring 11 and the yoke 15, and the magnetorheological fluid 8 exerts a shear stress according to the strength of the applied magnetic field. Then, by changing the value of the current applied to the coil 16, the shear stress of the magnetorheological fluid 8 can be changed, and therefore the torsional rigidity of the coupling 1 can also be changed.

In this way, with the coupling 1 according to this embodiment, the torsional rigidity of the coupling 1 can be changed simply by changing the current value applied to the coil 16, so 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.

<Modification of the first embodiment>
In the first embodiment of the present invention described above, the intermediate portion 7 is configured using a plurality of leaf springs 11. However, for example, as shown in Fig. 4, the number of leaf springs 11 used in the intermediate portion 7 may be one. In this case, the single leaf spring 11 is connected to both the first joint portion 5 and the second joint portion 6 by using connecting members 13, 14. The connecting members 13, 14 are arranged at equal intervals on a circumference centered on the rotation axis N, and the connecting member 13 arranged on the surface of the leaf spring 11 on the first joint portion 5 side and the connecting member 14 arranged on the surface of the leaf spring 11 on the second joint portion 6 side are arranged at different circumferential positions.

In addition, in the first embodiment of the present invention described above, a magnetic material is used for the intermediate yoke 15c, but in order to reliably form a magnetic path that penetrates the magnetorheological fluid 8 in the gap 20 between the leaf spring 11 and the ridge 15ca, the intermediate yoke 15c may be constructed using two types of material, a magnetic material and a non-magnetic material. For example, when viewed from the direction of the rotation axis N, the part of the intermediate yoke 15c that overlaps with the leaf spring 11 may be made of a magnetic material, and the other parts of the intermediate yoke 15c may be made of a non-magnetic material. Alternatively, the ridge 15ca of the intermediate yoke 15c may be made of a magnetic material, and the other parts of the intermediate yoke 15c may be made of a non-magnetic material.

Second Embodiment
Hereinafter, a coupling according to a second embodiment of the present invention will be described with reference to the drawings. Note that the same members as those described in the first embodiment will be denoted by the same reference numerals in the drawings, and the description thereof will be omitted.

As shown in FIG. 5, the coupling 1A according to this embodiment is connected between the driving side rotating shaft 2 and the driven side rotating shaft 3, and includes a first joint part 5A, a second joint part 6A, an intermediate part 7A, a magnetorheological fluid 8, and a magnetic field generating part 9A.

The first joint part 5A is attached to the drive side rotating shaft 2 so that it cannot rotate relative to the drive side rotating shaft 2, and rotates integrally with the drive side rotating shaft 2. The first joint part 5A is made of a magnetic material.

The second joint part 6A is attached to the driven rotating shaft 3 so that it cannot rotate relative to the driven rotating shaft 3, and rotates integrally with the driven rotating shaft 3. The second joint part 6A is made of a magnetic material.

The intermediate portion 7A is made of rubber and is connected between the first joint portion 5A and the second joint portion 6A. In this embodiment, the intermediate portion 7A is made of a central rubber member 7Aa provided on the rotation axis N and an annular rubber member 7Ab provided near the side of the first joint portion 5A and the second joint portion 6. One of the central rubber member 7Aa and the annular rubber member 7Ab is fixed to the first joint portion 5A, and the other is fixed to the second joint portion 6A. When a displacement occurs in the torsional direction between the driving side rotating shaft 2 and the driven side rotating shaft 3, the central rubber member 7Aa and the annular rubber member 7Ab elastically deform in the torsional direction. Therefore, when torsional vibration is input from the driving side rotating shaft 2 or the driven side rotating shaft 3, the central rubber member 7Aa and the annular rubber member 7Ab elastically deform in the torsional direction to absorb the torsional vibration.

A space for containing the magnetorheological fluid 8 is formed inside the annular rubber member 7Ab and in the gap between the first joint part 5A and the second joint part 6A. Therefore, the annular rubber member 7Ab also functions as a sealant that prevents the magnetorheological fluid 8 from leaking out of the gap between the first joint part 5A and the second joint part 6A.

The magnetorheological fluid 8 is disposed in the gap between the first joint part 5A and the second joint part 6A. In this embodiment, the magnetorheological fluid 8 is enclosed in the part shaded gray in FIG. 5.

The magnetic field generating unit 9A generates a magnetic field to be applied to the magnetorheological fluid 8. In this embodiment, the magnetic field generating unit 9A includes a yoke 15A and a coil 16.

In this embodiment, the yoke 15A is composed of a first inner yoke 15Aa, a second inner yoke 15Ab, and an outer yoke 15Ac. Naturally, all of the components that make up the yoke 15A are made of magnetic material.

In this embodiment, the first joint part 5A also serves as the first inner yoke 15Aa, and the second joint part 5B also serves as the second inner yoke 15Ab.

One end face of the outer yoke 15Ac faces the side face of the first inner yoke 15Aa via a small gap, and the other end face faces the side face of the second inner yoke 15Ab via a small gap. In this embodiment, the outer yoke 15Ac is formed in an overall ring shape and has a cross section that is approximately C-shaped.

As shown in FIG. 5, bearing housing members 17 are fixed to both sides of the outer yoke 15Ac. A bearing 18 is interposed between one bearing housing member 17 and the first joint part 5A, and a bearing 18 is interposed between the other bearing housing member 17 and the second joint part 6A. Therefore, the first joint part 5A, the second joint part 6A, and the intermediate part 7A are rotatable with respect to the outer yoke 15Ac and the coil 16.

The coil 16 is wound around the inside of the outer yoke 15Ac. A current of a desired value can be supplied to the coil 16 from the power supply unit 21.

When a current is applied to the coil 16 by the power supply unit 21 in the coupling 1A having the above-mentioned configuration, a magnetic path is formed in the yoke 15A, for example along the direction of the arrow P in FIG. 5. In particular, a magnetic path is formed that penetrates the magnetorheological fluid 8 present in the minute gap 20A between the first inner yoke 15Aa and the second inner yoke 15Ab, and the magnetorheological fluid 8 exerts a shear stress according to the strength of the applied magnetic field. Then, by changing the value of the current applied to the coil 16, the shear stress of the magnetorheological fluid 8 can be changed, and therefore the torsional rigidity of the coupling 1A can also be changed.

In this way, with the coupling 1A according to this embodiment, the torsional rigidity of the coupling 1A can be changed simply by changing the current value applied to the coil 16, so the torsional vibration input to the coupling 1A can be easily suppressed, and the resonance point of the torsional vibration can also be easily changed.

<Modification of the second embodiment>
In the second embodiment of the present invention described above, the intermediate portion 7A is made of rubber, but the intermediate portion 7A may be made of resin. For example, the central rubber member 7Aa provided on the rotation axis N may be replaced with a central resin member made of resin, and the annular rubber members 7Ab provided near the side surfaces of the first joint portion 5A and the second joint portion 6 may be replaced with an annular resin member made of resin. Of course, when a displacement occurs in the torsional direction between the driving side rotating shaft 2 and the driven side rotating shaft 3, the central resin member and the annular resin member elastically deform in the torsional direction in response to this.

Even with this type of coupling according to the modified example of the second embodiment, the same effects as those of the coupling 1A according to the second embodiment can be obtained.

The present invention can be applied, for example, to a coupling for connecting shafts.

REFERENCE SIGNS LIST 1, 1A Coupling 5, 5A First joint part 6, 6A Second joint part 7, 7A Intermediate part 8 Magnetorheological fluid 9, 9A Magnetic field generating part 11 Leaf spring 11A First leaf spring 11B Second leaf spring 12 Connecting member 13 Connecting member 14 Connecting member 15 Yoke 15a First inner yoke 15b Second inner yoke 15c Intermediate yoke 15d Outer yoke 16 Coil 20, 20A Micro gap

Claims (4)

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:
a magnetorheological fluid interposed between the first joint portion and the second joint portion;
A magnetic field generating unit that generates a magnetic field to be applied to the magnetorheological fluid;
Further comprising:
The intermediate portion has a leaf spring that is elastically deformed in a torsional direction,
The leaf spring is made of a magnetic material,
The magnetic field generating unit is
a yoke formed in a shape that sandwiches both surfaces of the leaf spring with a gap therebetween;
A coil wound in the yoke to form a magnetic path;
having
At least a portion of the magnetorheological fluid is present in the gap between the leaf spring and the yoke,
When a current is applied to the coil, a magnetic path is formed that passes through the magnetorheological fluid present in the gap between the leaf spring and the yoke.
A coupling characterized by: 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:
a magnetorheological fluid interposed between the first joint portion and the second joint portion;
A magnetic field generating unit that generates a magnetic field to be applied to the magnetorheological fluid;
Further comprising:
The intermediate portion has a leaf spring that is elastically deformed in a torsional direction,
The intermediate portion includes a plurality of the leaf springs,
The plurality of leaf springs are made of a magnetic material, and adjacent ones are connected to each other via a connecting member so as to be elastically deformable in a torsional direction,
The magnetic field generating unit is
a yoke formed in a shape that sandwiches both surfaces of each of the leaf springs with a gap therebetween;
A coil wound so as to form a magnetic path within the yoke;
having
At least a portion of the magnetorheological fluid is present in the gap between the leaf spring and the yoke,
When a current is applied to the coil, a magnetic path is formed that passes through the magnetorheological fluid present in the gap between the leaf springs and the yoke.
A coupling characterized by: 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:
a magnetorheological fluid interposed between the first joint portion and the second joint portion;
A magnetic field generating unit that generates a magnetic field to be applied to the magnetorheological fluid;
Further comprising:
the intermediate portion has rubber or resin that is elastically deformable in a torsional direction,
The rubber or the resin undergoes torsional deformation around the rotation axis of the coupling.
A coupling characterized by: The coupling according to claim 3,
The rubber or the resin functions as a vibration absorbing material that absorbs torsional vibrations, and also functions as a sealing material that prevents the magnetorheological fluid from leaking from between the first joint part and the second joint part.
A coupling characterized by: