JP2016205589A - Rotation transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation transmission device capable of reducing drag loss in non-application of magnetic field without lowering transmission torque.SOLUTION: A movable element 14 is disposed in a state that it can approach or separate from a rotor 12. The movable element 14 approaches the rotor 12 in energization of a coil 24 to form a magnetic circuit with a yoke 25 and the rotor 12, and separates from the rotor 12 in non-energization of the coil 24. According to this constitution, torque can be sufficiently transmitted between the movable element 14 and the rotor 12 through a magnetic viscous fluid 16 in energization of the coil 24, and a clearance between the movable element 14 and the rotor 12 is widened in non-energization of the coil 24, so that drag loss is reduced. Thus the drag loss can be reduced in non-application of magnetic field without lowering the transmission torque.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotation transmission device.

  Conventionally, a rotation transmission device using a functional fluid such as a magnetorheological fluid is known. Patent Document 1 discloses a rotary braking device including a hollow housing in which an electromagnet is incorporated, a disk-shaped rotor provided in the housing, and a magnetorheological fluid provided in a gap between the housing and the rotor. It is disclosed. In this rotary braking device, when the electromagnet is energized, the magnetorheological fluid mainly in the gap between the rotor disk and the electromagnet yoke is magnetized, and the rotor and housing are interposed between the magnetized magnetorheological fluid. Rotation is transmitted.

JP 2011-202745 A

  By the way, a functional fluid such as a magnetorheological fluid that magnetizes when placed in a magnetic field has a relatively large viscosity even when it is not magnetized. Therefore, there is a problem that drag loss due to the stickiness of the functional fluid is large when no magnetic field is applied.

On the other hand, it is conceivable to reduce drag loss by widening the gap between the rotor and the housing. However, when the gap between the rotor and the housing is widened, there is a drawback that the torque transmitted between the rotor and the housing is reduced when a magnetic field is applied.
The present invention has been made in view of the above points, and an object of the present invention is to provide a rotation transmission device in which drag loss when no magnetic field is applied is reduced without reducing transmission torque.

  A rotation transmission device according to the present invention includes a hollow housing, a rotor provided in the housing, a coil that generates a magnetic field in the housing by energization, a yoke made of a magnetic material, a mover made of a magnetic material, Functional fluid. The rotor is rotatable relative to the housing. The yoke is provided around the coil and is formed integrally with the housing. The mover engages with the housing in the circumferential direction. The functional fluid is provided in the gap between the rotor and the mover and increases in viscosity when magnetized in a magnetic field generated by a coil.

The present invention includes a first invention and a second invention.
In the first invention, the mover can approach and separate from the rotor, approaches the rotor when the coil is energized, forms a magnetic circuit with the yoke and the rotor, and is separated from the rotor when the coil is not energized.
With this configuration, torque is sufficiently transmitted between the mover and the rotor via the functional fluid when the coil is energized, but the gap between the mover and the rotor is widened when the coil is not energized. As a result, drag loss is reduced. Therefore, according to the first invention, drag loss when no magnetic field is applied can be reduced without reducing the transmission torque.

In the second invention, the mover is provided so as to face the rotor in the axial direction, and is movable in the radial direction. The mover moves radially outward when the coil is energized to form a magnetic circuit together with the yoke and the rotor, and moves radially inward when the coil is not energized.
With this configuration, when the coil is energized, the gap between the mover and the rotor moves radially outward, and torque is sufficiently transmitted between the mover and the rotor via the functional fluid. On the other hand, when the coil is not energized, the gap between the mover and the rotor moves radially inward, and drag loss is reduced. When the gap between the two members is the same, the drag loss is smaller as the radial position is on the inner side. Therefore, according to the second aspect, drag loss when no magnetic field is applied can be reduced without reducing the transmission torque.

It is a longitudinal cross-sectional view of the rotation transmission apparatus by 1st Embodiment of this invention. It is the II-II sectional view taken on the line of the rotation transmission apparatus of FIG. It is sectional drawing which shows the state which the needle | mover approached the rotor from the state of FIG. It is a longitudinal cross-sectional view of the rotation transmission apparatus by 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the rotation transmission apparatus by 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the rotation transmission apparatus by 4th Embodiment of this invention. It is the VII-VII sectional view taken on the line of the rotation transmission device of FIG. It is sectional drawing which shows the state which the needle | mover moved to the radial inside from the state of FIG. It is the IX-IX sectional view taken on the line of the rotation transmission apparatus of FIG. It is a longitudinal cross-sectional view of the rotation transmission apparatus by 5th Embodiment of this invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
[First Embodiment]
A rotation transmission device according to a first embodiment of the present invention will be described with reference to FIGS.
The rotation transmission device 10 can switch between transmission and interruption of rotation between the fixing member 91 and the shaft 92. The fixed member 91 is a non-rotating member. In the present embodiment, the rotation transmission device 10 is used as a brake.

  As shown in FIGS. 1 and 2, the rotation transmission device 10 includes a housing 11, a rotor 12, an electromagnet 13, a mover 14, a spring 15, and a magnetorheological fluid 16. The mover 14 corresponds to a “movable element” recited in the claims. The spring 15 corresponds to an “elastic member” recited in the claims.

  The housing 11 includes a cup-shaped first housing part 21, a disk-shaped second housing part 22 provided on the opening side of the first housing part 21, a first housing part 21, and a second housing part 22. Cover portion 23 for closing the gap. The first housing portion 21 is provided coaxially with the shaft 92. The first housing part 21 and the second housing part 22 are made of a magnetic material, and the cover part 23 is made of a nonmagnetic material. A seal member 18 is provided between the first housing part 21 and the cover part 23, and a seal member 19 is provided between the second housing part 22 and the cover part 23.

  The rotor 12 is provided in the housing 11 and is rotatable relative to the housing. The rotor 12 is provided coaxially with the shaft 92 and is fixed to the end of the shaft 92. In the present embodiment, the rotor 12 is entirely made of a magnetic material.

  The electromagnet 13 has a coil 24 and a yoke 25. The coil 24 generates a magnetic field extending in the housing 11 by energization. The yoke 25 is made of a magnetic material, is provided around the coil 24, and is formed integrally with the first housing portion 21. In the present embodiment, the yoke 25 is the same member as the first housing portion 21 and is formed on the inner wall of the outer peripheral portion of the first housing portion 21. The yoke 25 has a cup shape having a cylindrical portion 26 and a bottom portion 27. The coil 24 is provided inside the cylindrical portion 26 and is wound around a cylindrical bobbin 28 that is a nonmagnetic material.

  The mover 14 is made of a magnetic material and engages with the housing 11 in the circumferential direction. The movable element 14 is provided on the opposite side of the bottom portion 27 with respect to the cylindrical portion 26 of the yoke 25, can approach and separate from the end portion of the cylindrical portion 26, and can approach and separate from the rotor 12. In the present embodiment, the mover 14 has an annular shape, has a spline hole 31, and is fitted to the spline teeth 32 on the outer peripheral portion of the second housing portion 22.

  A cover portion 23 made of a nonmagnetic material is provided in a portion of the housing 11 that is radially outward of the mover 14. There is nothing other than the mover 14 that magnetically bypasses the cylindrical portion 26 of the yoke 25 and the rotor 12. Therefore, the cylindrical portion 26 of the yoke 25 generates a magnetic attractive force that attracts the mover 14 when the coil 24 is energized. As shown in FIG. 3, the mover 14 approaches the rotor 12 by being attracted to the end of the cylindrical portion 26 opposite to the bottom 27 by the magnetic attractive force generated by the yoke 25. The rotor 12 is provided to face the bottom 27 of the yoke 25 inside the coil 24. When the mover 14 approaches the rotor 12, it forms a magnetic circuit together with the yoke 25 and the rotor 12.

  The spring 15 is a compression coil spring and biases the mover 14 away from the rotor 12. As shown in FIG. 1, the mover 14 is separated from the rotor 12 by receiving the biasing force of the spring 15 when the coil 24 is not energized.

  The magnetorheological fluid 16 fills the space in the housing 11 and is provided in the gap 33 between the rotor 12 and the mover 14 and the gap 34 between the rotor 12 and the bottom 27 of the yoke 25. As shown in FIG. 3, the magnetorheological fluid 16 is a functional fluid whose viscosity increases when magnetized in a magnetic field generated by the coil 24. Specifically, the magnetized particles in the magnetorheological fluid 16 in the gaps 33 and 34 are connected to line up along the magnetic circuit. Therefore, the circumferential external friction acting between the magnetorheological fluid 16 and the rotor 12, the mover 14, and the yoke 25 and the inner friction in the circumferential direction of the magnetorheological fluid 16 are increased. As a result, a large torque can be transmitted between the rotor 12 and the mover 14 and between the rotor 12 and the yoke 25.

  The space in the housing 11 is partitioned by the mover 14 into one side and the other side in the moving direction of the mover 14. The moving direction of the mover 14 is the axial direction. The mover 14 has a passage 35 penetrating from one side in the axial direction to the other side. The magnetorheological fluid 16 on one side in the axial direction with respect to the mover 14 can move through the passage 35 to the other side in the axial direction with respect to the mover 14.

(effect)
As described above, in the first embodiment, the mover 14 that can approach and separate from the rotor 12 is provided. The mover 14 approaches the rotor 12 when the coil 24 is energized, forms a magnetic circuit with the yoke 25 and the rotor 12, and is separated from the rotor 12 when the coil 24 is not energized.
With this configuration, torque is sufficiently transmitted between the mover 14 and the rotor 12 via the magnetorheological fluid 16 when the coil 24 is energized, but the mover 14 and the rotor are not energized when the coil 24 is de-energized. 12 becomes wider and drag loss is reduced. Therefore, drag loss when no magnetic field is applied can be reduced without reducing the transmission torque.

  In the first embodiment, the mover 14 approaches the rotor 12 by being attracted to the yoke 25 by a magnetic attractive force generated by the yoke 25 when the coil 24 is energized. Therefore, it is not necessary to separately provide an actuator for driving the mover 14.

  In the first embodiment, the yoke 25 has a cup shape having a cylindrical portion 26 and a bottom portion 27. The mover 14 can approach and be separated from the end of the cylindrical portion 26 opposite to the bottom 27. A portion of the housing 11 that is radially outward from the mover 14 is made of a nonmagnetic material. Therefore, the cylindrical portion 26 of the yoke 25 can generate a magnetic attractive force that attracts the mover 14 when the coil 24 is energized.

  In the first embodiment, a spring 15 that separates the mover 14 from the rotor 12 when the coil 24 is not energized is provided. Therefore, it is not necessary to separately provide an actuator for driving the mover 14. Further, the movable element 14 can be separated from the rotor 12 without consuming electric power.

  Moreover, in 1st Embodiment, the needle | mover 14 has the channel | path 35 which penetrates from the one side of the moving direction of the said needle | mover 14 to the other side. Thus, the magnetorheological fluid 16 on one side in the axial direction with respect to the mover 14 can move to the other side in the axial direction with respect to the mover 14 through the passage 35. Therefore, even if the mover 14 moves, the volume of the space where the magnetorheological fluid 16 exists in the housing 11 does not change. Accordingly, leakage of the magnetorheological fluid 16 to the outside can be suppressed.

[Second Embodiment]
In the second embodiment of the present invention, as shown in FIG. 4, the yoke 25 is formed integrally with the housing 41, but is a separate member from the housing 41. The housing 41 has a resin-made cup-shaped first housing part 42 and a resin-made cup-shaped second housing part 43 combined with the opening of the first housing part 42.
Thus, even if the yoke 25 is a separate member from the housing 41, the same effect as in the first embodiment can be obtained.

[Third Embodiment]
In 3rd Embodiment of this invention, as shown in FIG. 5, the channel | path 35 in 1st Embodiment is not provided. Instead, the tooth bottom part of the spline hole 52 of the needle | mover 51 is extended to the radial direction outer side. Thus, a passage 53 is formed between the spline teeth 32 and the spline hole 52 so as to penetrate from the one side to the other side in the moving direction of the mover 51.
Thus, the passage 53 may be formed between the spline teeth 32 and the spline holes 52.

[Fourth Embodiment]
In the fourth embodiment of the present invention, as shown in FIGS. 6 and 7, a plurality of movers 61 are provided in the circumferential direction. The mover 61 is provided so as to face the rotor 12 in the axial direction, and is movable in the radial direction. The housing 64 has an opening 65 for guiding the mover 61 in the radial direction. As shown in FIGS. 8 and 9, the mover 61 is attracted to an end portion of the cylindrical portion 26 opposite to the bottom portion 27 by a magnetic attractive force generated by the yoke 25 when the coil 24 is energized. It moves radially outward to form a magnetic circuit together with the yoke 25 and the rotor 12. On the other hand, as shown in FIGS. 6 and 7, the mover 61 moves radially inward under the biasing force of the spring 62 when the coil 24 is not energized.

  With this configuration, when the coil 24 is energized, the gap 63 between the mover 61 and the rotor 12 moves radially outward, and torque is generated between the mover 61 and the rotor 12 via the magnetorheological fluid 16. Fully communicated. On the other hand, when the coil 24 is not energized, the gap 63 between the mover 61 and the rotor 12 moves radially inward, and drag loss is reduced. When the distance between the gaps 63 of the two members is the same, the drag loss is smaller as the radial position is on the inner side. Therefore, drag loss when no magnetic field is applied can be reduced without reducing the transmission torque.

[Fifth Embodiment]
In the fifth embodiment of the present invention, as shown in FIG. 10, the housing 71 includes a cylindrical first housing part 73 including a cylindrical yoke 72, and one axial side with respect to the first housing part 73. The disc-shaped second housing portion 74 provided, the disc-shaped third housing portion 75 provided on the other side in the axial direction with respect to the first housing portion 73, the first housing portion 73 and the first housing portion 73 The cover portion 23 that closes the gap between the second housing portion 74 and the cover portion 23 that closes the gap between the first housing portion 73 and the third housing portion 75 is provided.

In the fifth embodiment, one mover 14 is provided on each side of the rotor 12 in the axial direction. Both the movers 14 are separated from the rotor 12 when the coil 24 is not energized.
With this configuration, not only the gap 33 on one side in the axial direction with respect to the rotor 12 but also the gap 34 on the other side in the axial direction with respect to the rotor 12 is widened when the coil 24 is not energized. Therefore, drag loss is further reduced as compared with the first embodiment.

[Other Embodiments]
In another embodiment of the present invention, other functional fluids such as a magnetic fluid or an electrorheological fluid may be used instead of the magnetorheological fluid.
In another embodiment of the present invention, instead of a spring that is a compression coil spring, other elastic members such as a wave washer, a disc spring, and a tension coil spring may be used.

In another embodiment of the present invention, the mover may be provided to be separated from the rotor in the radial direction.
In another embodiment of the present invention, an actuator for driving the mover may be provided.
In another embodiment of the present invention, as long as at least the portion facing the mover is a magnetic body, the other portion may be a non-magnetic body.
In other embodiments of the present invention, a portion of the coil and yoke may be located outside the housing. In short, the coil only needs to apply a magnetic field in the housing, and the yoke only needs to attract the mover when the coil is energized.

In another embodiment of the present invention, the nonmagnetic material is not limited to resin, and may be, for example, a nonmagnetic metal.
In another embodiment of the present invention, the rotation transmission device may be used as a clutch provided between the rotating member and the rotating member.
The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 11, 41 ... Housing 12 ... Rotor 14, 51, 61 ... Mover 16 ... Magnetorheological fluid (functional fluid)
24 ... Coil 25 ... Yoke 33, 63 ... Gap

Claims (7)

Hollow housings (11, 41);
A rotor (12) provided in the housing and rotatable relative to the housing;
A coil (24) for generating a magnetic field in the housing by energization;
A yoke (25) made of a magnetic material, provided around the coil and formed integrally with the housing;
It is made of a magnetic material, engages with the housing in the circumferential direction, can approach and separate from the rotor, and approaches the rotor when the coil is energized to form a magnetic circuit with the yoke and the rotor. A mover (14, 51) that is separated from the rotor when the current is not energized;
A functional fluid (16) that is provided in a gap (33) between the rotor and the mover and increases in viscosity when magnetized in a magnetic field generated by the coil;
A rotation transmission device comprising: A hollow housing;
A rotor provided in the housing and rotatable relative to the housing;
A coil that generates a magnetic field extending in the housing by energization;
A yoke made of a magnetic material, provided around the coil, and formed integrally with the housing;
It is made of a magnetic material, is provided to face the rotor in the axial direction, engages with the housing in the circumferential direction, is movable in the radial direction, and moves radially outward when the coil is energized to move the yoke and A mover (61) that forms a magnetic circuit with the rotor and moves radially inward when the coil is de-energized;
A functional fluid that is provided in a gap (63) between the rotor and the mover and increases in viscosity when magnetized in a magnetic field generated by the coil;
A rotation transmission device comprising:   3. The rotation transmission device according to claim 1, wherein the mover approaches the rotor by being attracted to the yoke by a magnetic attractive force generated by the yoke when the coil is energized. The yoke has a cylindrical portion (26), and the mover is provided to be close to and away from an end of the cylindrical portion,
The rotation transmission device according to claim 3, wherein a portion of the housing that is radially outward with respect to the mover is made of a nonmagnetic material.   The rotation transmission device according to any one of claims 1 to 4, further comprising an elastic member (15, 62) for separating the mover from the rotor when the coil is not energized. The space in the housing is partitioned by the mover into one side and the other side in the moving direction of the mover,
The rotation transmission device according to any one of claims 1 to 5, wherein the mover has a passage (35, 53) penetrating from one side to the other side in the moving direction of the mover.   The rotation transmission device according to any one of claims 1 to 6, wherein one mover is provided on each side of the rotor in the axial direction.

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